[net-next,v2,0/3] add the dwmac driver for T-HEAD TH1520 SoC

Add the dwmac driver support for T-HEAD TH1520 SoC.

Since the clk part isn't mainlined, so SoC dts(i) changes are not
included in this series. However, it can be tested by using fixed-clock.

Since v1:
  - rebase on the lastest net-next
  - collect Reviewed-by tag
  - address Krzysztof's comment of the dt binding
  - fix "div is not initialised" issue pointed out by Simon

Jisheng Zhang (3):
  dt-bindings: net: snps,dwmac: allow dwmac-3.70a to set pbl properties
  dt-bindings: net: add T-HEAD dwmac support
  net: stmmac: add glue layer for T-HEAD TH1520 SoC

 .../devicetree/bindings/net/snps,dwmac.yaml   |   2 +
 .../devicetree/bindings/net/thead,dwmac.yaml  |  77 +++++
 drivers/net/ethernet/stmicro/stmmac/Kconfig   |  11 +
 drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
 .../net/ethernet/stmicro/stmmac/dwmac-thead.c | 302 ++++++++++++++++++
 5 files changed, 393 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/net/thead,dwmac.yaml
 create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c

On Sun, Aug 27, 2023 at 05:17:10PM +0800, Jisheng Zhang wrote:
> Add dwmac glue driver to support the dwmac on the T-HEAD TH1520 SoC.
> 
> Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> ---
>  drivers/net/ethernet/stmicro/stmmac/Kconfig   |  11 +
>  drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
>  .../net/ethernet/stmicro/stmmac/dwmac-thead.c | 302 ++++++++++++++++++
>  3 files changed, 314 insertions(+)
>  create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> index 06c6871f8788..1bf71804c270 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
> +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> @@ -216,6 +216,17 @@ config DWMAC_SUN8I
>  	  stmmac device driver. This driver is used for H3/A83T/A64
>  	  EMAC ethernet controller.
>  
> +config DWMAC_THEAD
> +	tristate "T-HEAD dwmac support"
> +	depends on OF && (ARCH_THEAD || COMPILE_TEST)
> +	select MFD_SYSCON
> +	help
> +	  Support for ethernet controllers on T-HEAD RISC-V SoCs
> +
> +	  This selects the T-HEAD platform specific glue layer support for
> +	  the stmmac device driver. This driver is used for T-HEAD TH1520
> +	  ethernet controller.
> +
>  config DWMAC_IMX8
>  	tristate "NXP IMX8 DWMAC support"
>  	default ARCH_MXC
> diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
> index 5b57aee19267..d73171ed6ad7 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/Makefile
> +++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
> @@ -27,6 +27,7 @@ obj-$(CONFIG_DWMAC_STI)		+= dwmac-sti.o
>  obj-$(CONFIG_DWMAC_STM32)	+= dwmac-stm32.o
>  obj-$(CONFIG_DWMAC_SUNXI)	+= dwmac-sunxi.o
>  obj-$(CONFIG_DWMAC_SUN8I)	+= dwmac-sun8i.o
> +obj-$(CONFIG_DWMAC_THEAD)	+= dwmac-thead.o
>  obj-$(CONFIG_DWMAC_DWC_QOS_ETH)	+= dwmac-dwc-qos-eth.o
>  obj-$(CONFIG_DWMAC_INTEL_PLAT)	+= dwmac-intel-plat.o
>  obj-$(CONFIG_DWMAC_GENERIC)	+= dwmac-generic.o
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> new file mode 100644
> index 000000000000..85135ef05906
> --- /dev/null
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> @@ -0,0 +1,302 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * T-HEAD DWMAC platform driver
> + *
> + * Copyright (C) 2021 Alibaba Group Holding Limited.
> + * Copyright (C) 2023 Jisheng Zhang <jszhang@kernel.org>
> + *
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_net.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#include "stmmac_platform.h"
> +
> +#define GMAC_CLK_EN			0x00
> +#define  GMAC_TX_CLK_EN			BIT(1)
> +#define  GMAC_TX_CLK_N_EN		BIT(2)
> +#define  GMAC_TX_CLK_OUT_EN		BIT(3)
> +#define  GMAC_RX_CLK_EN			BIT(4)
> +#define  GMAC_RX_CLK_N_EN		BIT(5)
> +#define  GMAC_EPHY_REF_CLK_EN		BIT(6)
> +#define GMAC_RXCLK_DELAY_CTRL		0x04
> +#define  GMAC_RXCLK_BYPASS		BIT(15)
> +#define  GMAC_RXCLK_INVERT		BIT(14)
> +#define  GMAC_RXCLK_DELAY_MASK		GENMASK(4, 0)
> +#define  GMAC_RXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> +#define GMAC_TXCLK_DELAY_CTRL		0x08
> +#define  GMAC_TXCLK_BYPASS		BIT(15)
> +#define  GMAC_TXCLK_INVERT		BIT(14)
> +#define  GMAC_TXCLK_DELAY_MASK		GENMASK(4, 0)
> +#define  GMAC_TXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> +#define GMAC_PLLCLK_DIV			0x0c
> +#define  GMAC_PLLCLK_DIV_EN		BIT(31)
> +#define  GMAC_PLLCLK_DIV_MASK		GENMASK(7, 0)
> +#define  GMAC_PLLCLK_DIV_NUM(x)		FIELD_PREP(GMAC_PLLCLK_DIV_MASK, (x))
> +#define GMAC_GTXCLK_SEL			0x18
> +#define  GMAC_GTXCLK_SEL_PLL		BIT(0)
> +#define GMAC_INTF_CTRL			0x1c
> +#define  PHY_INTF_MASK			BIT(0)
> +#define  PHY_INTF_RGMII			FIELD_PREP(PHY_INTF_MASK, 1)
> +#define  PHY_INTF_MII_GMII		FIELD_PREP(PHY_INTF_MASK, 0)
> +#define GMAC_TXCLK_OEN			0x20
> +#define  TXCLK_DIR_MASK			BIT(0)
> +#define  TXCLK_DIR_OUTPUT		FIELD_PREP(TXCLK_DIR_MASK, 0)
> +#define  TXCLK_DIR_INPUT		FIELD_PREP(TXCLK_DIR_MASK, 1)
> +
> +#define GMAC_GMII_RGMII_RATE	125000000
> +#define GMAC_MII_RATE		25000000
> +
> +struct thead_dwmac {
> +	struct plat_stmmacenet_data *plat;
> +	struct regmap *apb_regmap;
> +	struct device *dev;
> +	u32 rx_delay;
> +	u32 tx_delay;
> +};
> +
> +static int thead_dwmac_set_phy_if(struct plat_stmmacenet_data *plat)
> +{
> +	struct thead_dwmac *dwmac = plat->bsp_priv;
> +	u32 phyif;
> +
> +	switch (plat->interface) {
> +	case PHY_INTERFACE_MODE_MII:
> +		phyif = PHY_INTF_MII_GMII;
> +		break;
> +	case PHY_INTERFACE_MODE_RGMII:
> +	case PHY_INTERFACE_MODE_RGMII_ID:
> +	case PHY_INTERFACE_MODE_RGMII_TXID:
> +	case PHY_INTERFACE_MODE_RGMII_RXID:
> +		phyif = PHY_INTF_RGMII;
> +		break;
> +	default:
> +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> +			plat->interface);
> +		return -EINVAL;
> +	};
> +
> +	regmap_write(dwmac->apb_regmap, GMAC_INTF_CTRL, phyif);
> +
> +	return 0;
> +}
> +
> +static int thead_dwmac_set_txclk_dir(struct plat_stmmacenet_data *plat)
> +{
> +	struct thead_dwmac *dwmac = plat->bsp_priv;
> +	u32 txclk_dir;
> +
> +	switch (plat->interface) {
> +	case PHY_INTERFACE_MODE_MII:
> +		txclk_dir = TXCLK_DIR_INPUT;
> +		break;
> +	case PHY_INTERFACE_MODE_RGMII:
> +	case PHY_INTERFACE_MODE_RGMII_ID:
> +	case PHY_INTERFACE_MODE_RGMII_TXID:
> +	case PHY_INTERFACE_MODE_RGMII_RXID:
> +		txclk_dir = TXCLK_DIR_OUTPUT;
> +		break;
> +	default:
> +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> +			plat->interface);
> +		return -EINVAL;
> +	};
> +
> +	regmap_write(dwmac->apb_regmap, GMAC_TXCLK_OEN, txclk_dir);
> +
> +	return 0;
> +}
> +
> +static void thead_dwmac_fix_speed(void *priv, unsigned int speed, unsigned int mode)
> +{
> +	struct thead_dwmac *dwmac = priv;
> +	struct plat_stmmacenet_data *plat = dwmac->plat;
> +	unsigned long rate;
> +	u32 div;
> +
> +	switch (plat->interface) {
> +	/* For MII, rxc/txc is provided by phy */
> +	case PHY_INTERFACE_MODE_MII:
> +		return;
> +
> +	case PHY_INTERFACE_MODE_RGMII:
> +	case PHY_INTERFACE_MODE_RGMII_ID:
> +	case PHY_INTERFACE_MODE_RGMII_RXID:
> +	case PHY_INTERFACE_MODE_RGMII_TXID:

> +		rate = clk_get_rate(plat->stmmac_clk);
> +		if (!rate || rate % GMAC_GMII_RGMII_RATE != 0 ||
> +		    rate % GMAC_MII_RATE != 0) {
> +			dev_err(dwmac->dev, "invalid gmac rate %ld\n", rate);
> +			return;
> +		}
> +
> +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV, GMAC_PLLCLK_DIV_EN, 0);
> +
> +		switch (speed) {
> +		case SPEED_1000:
> +			div = rate / GMAC_GMII_RGMII_RATE;
> +			break;
> +		case SPEED_100:
> +			div = rate / GMAC_MII_RATE;
> +			break;
> +		case SPEED_10:
> +			div = rate * 10 / GMAC_MII_RATE;
> +			break;
> +		default:
> +			dev_err(dwmac->dev, "invalid speed %u\n", speed);
> +			return;
> +		}
> +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> +				   GMAC_PLLCLK_DIV_MASK, GMAC_PLLCLK_DIV_NUM(div));
> +
> +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> +				   GMAC_PLLCLK_DIV_EN, GMAC_PLLCLK_DIV_EN);

This chunk looks like a hard-coded implementation of the
CLK_SET_RATE_GATE Tx-clocks rate setup which parental clock is the
"stmmaceth" clock. I suggest to move it to the respective driver, add
a "tx" clock to the bindings and use the common clock kernel API
methods here only.

> +		break;
> +	default:
> +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> +			plat->interface);
> +		return;
> +	}
> +}
> +
> +static int thead_dwmac_enable_clk(struct plat_stmmacenet_data *plat)
> +{
> +	struct thead_dwmac *dwmac = plat->bsp_priv;
> +	u32 reg;
> +
> +	switch (plat->interface) {
> +	case PHY_INTERFACE_MODE_MII:
> +		reg = GMAC_RX_CLK_EN | GMAC_TX_CLK_EN;
> +		break;
> +
> +	case PHY_INTERFACE_MODE_RGMII:
> +	case PHY_INTERFACE_MODE_RGMII_ID:
> +	case PHY_INTERFACE_MODE_RGMII_RXID:
> +	case PHY_INTERFACE_MODE_RGMII_TXID:
> +		/* use pll */
> +		regmap_write(dwmac->apb_regmap, GMAC_GTXCLK_SEL, GMAC_GTXCLK_SEL_PLL);
> +

> +		reg = GMAC_TX_CLK_EN | GMAC_TX_CLK_N_EN | GMAC_TX_CLK_OUT_EN |
> +		      GMAC_RX_CLK_EN | GMAC_RX_CLK_N_EN;

Similarly settings these flags looks like just clock gates which can
also be moved to the clock driver.

> +		break;
> +
> +	default:
> +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> +			plat->interface);
> +		return -EINVAL;
> +	}
> +
> +	regmap_write(dwmac->apb_regmap, GMAC_CLK_EN, reg);
> +
> +	return 0;
> +}
> +
> +static int thead_dwmac_init(struct platform_device *pdev,
> +			    struct plat_stmmacenet_data *plat)
> +{
> +	struct thead_dwmac *dwmac = plat->bsp_priv;
> +	int ret;
> +
> +	ret = thead_dwmac_set_phy_if(plat);
> +	if (ret)
> +		return ret;
> +
> +	ret = thead_dwmac_set_txclk_dir(plat);
> +	if (ret)
> +		return ret;
> +
> +	regmap_write(dwmac->apb_regmap, GMAC_RXCLK_DELAY_CTRL,
> +		     GMAC_RXCLK_DELAY_VAL(dwmac->rx_delay));
> +	regmap_write(dwmac->apb_regmap, GMAC_TXCLK_DELAY_CTRL,
> +		     GMAC_TXCLK_DELAY_VAL(dwmac->tx_delay));
> +
> +	thead_dwmac_fix_speed(dwmac, SPEED_1000, 0);
> +
> +	return thead_dwmac_enable_clk(plat);
> +}
> +
> +static int thead_dwmac_probe(struct platform_device *pdev)
> +{
> +	struct plat_stmmacenet_data *plat;
> +	struct stmmac_resources stmmac_res;
> +	struct thead_dwmac *dwmac;
> +	struct device_node *np = pdev->dev.of_node;
> +	u32 delay_ps;
> +	int ret;
> +
> +	ret = stmmac_get_platform_resources(pdev, &stmmac_res);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret,
> +				     "failed to get resources\n");
> +

> +	plat = stmmac_probe_config_dt(pdev, stmmac_res.mac);

This can be replaced with devm_stmmac_probe_config_dt() so the
stmmac_remove_config_dt() invocation would be dropped.

> +	if (IS_ERR(plat))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(plat),
> +				     "dt configuration failed\n");
> +
> +	dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
> +	if (!dwmac) {
> +		ret = -ENOMEM;
> +		goto err_remove_config_dt;
> +	}
> +
> +	if (!of_property_read_u32(np, "rx-internal-delay-ps", &delay_ps))
> +		dwmac->rx_delay = delay_ps;
> +	if (!of_property_read_u32(np, "tx-internal-delay-ps", &delay_ps))
> +		dwmac->tx_delay = delay_ps;
> +
> +	dwmac->apb_regmap = syscon_regmap_lookup_by_phandle(np, "thead,gmacapb");
> +	if (IS_ERR(dwmac->apb_regmap)) {
> +		ret = dev_err_probe(&pdev->dev, PTR_ERR(dwmac->apb_regmap),
> +				    "Failed to get gmac apb syscon\n");
> +		goto err_remove_config_dt;
> +	}
> +
> +	dwmac->dev = &pdev->dev;
> +	dwmac->plat = plat;
> +	plat->bsp_priv = dwmac;
> +	plat->fix_mac_speed = thead_dwmac_fix_speed;
> +

> +	ret = thead_dwmac_init(pdev, plat);
> +	if (ret)
> +		goto err_remove_config_dt;
> +
> +	ret = stmmac_dvr_probe(&pdev->dev, plat, &stmmac_res);

This can be replaced with:
plat->init = thead_dwmac_init;
ret = devm_stmmac_pltfr_probe();

> +	if (ret)
> +		goto err_remove_config_dt;
> +
> +	return 0;
> +

> +err_remove_config_dt:
> +	stmmac_remove_config_dt(pdev, plat);
> +
> +	return ret;

This can be dropped if devm_stmmac_probe_config_dt() is utilized.

> +}
> +
> +static const struct of_device_id thead_dwmac_match[] = {

> +	{ .compatible = "thead,th1520-dwmac" },

See my comment to the bindings about the compatible string suffix.

> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, thead_dwmac_match);
> +
> +static struct platform_driver thead_dwmac_driver = {
> +	.probe = thead_dwmac_probe,

> +	.remove_new = stmmac_pltfr_remove,

This can be dropped if devm_stmmac_probe_config_dt() and
devm_stmmac_pltfr_probe() are utilized.

> +	.driver = {
> +		.name = "thead-dwmac",
> +		.pm = &stmmac_pltfr_pm_ops,
> +		.of_match_table = thead_dwmac_match,
> +	},
> +};
> +module_platform_driver(thead_dwmac_driver);
> +
> +MODULE_AUTHOR("T-HEAD");
> +MODULE_AUTHOR("Jisheng Zhang <jszhang@kernel.org>");

> +MODULE_DESCRIPTION("T-HEAD dwmac platform driver");
                              ^
                              |
Capitalize? ------------------+

-Serge(y)

> +MODULE_LICENSE("GPL");
> -- 
> 2.40.1
> 
>

On Mon, Aug 28, 2023 at 04:40:19PM +0300, Serge Semin wrote:
> On Sun, Aug 27, 2023 at 05:17:10PM +0800, Jisheng Zhang wrote:
> > Add dwmac glue driver to support the dwmac on the T-HEAD TH1520 SoC.
> > 
> > Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> > ---
> >  drivers/net/ethernet/stmicro/stmmac/Kconfig   |  11 +
> >  drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
> >  .../net/ethernet/stmicro/stmmac/dwmac-thead.c | 302 ++++++++++++++++++
> >  3 files changed, 314 insertions(+)
> >  create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > 
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > index 06c6871f8788..1bf71804c270 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > @@ -216,6 +216,17 @@ config DWMAC_SUN8I
> >  	  stmmac device driver. This driver is used for H3/A83T/A64
> >  	  EMAC ethernet controller.
> >  
> > +config DWMAC_THEAD
> > +	tristate "T-HEAD dwmac support"
> > +	depends on OF && (ARCH_THEAD || COMPILE_TEST)
> > +	select MFD_SYSCON
> > +	help
> > +	  Support for ethernet controllers on T-HEAD RISC-V SoCs
> > +
> > +	  This selects the T-HEAD platform specific glue layer support for
> > +	  the stmmac device driver. This driver is used for T-HEAD TH1520
> > +	  ethernet controller.
> > +
> >  config DWMAC_IMX8
> >  	tristate "NXP IMX8 DWMAC support"
> >  	default ARCH_MXC
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > index 5b57aee19267..d73171ed6ad7 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/Makefile
> > +++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > @@ -27,6 +27,7 @@ obj-$(CONFIG_DWMAC_STI)		+= dwmac-sti.o
> >  obj-$(CONFIG_DWMAC_STM32)	+= dwmac-stm32.o
> >  obj-$(CONFIG_DWMAC_SUNXI)	+= dwmac-sunxi.o
> >  obj-$(CONFIG_DWMAC_SUN8I)	+= dwmac-sun8i.o
> > +obj-$(CONFIG_DWMAC_THEAD)	+= dwmac-thead.o
> >  obj-$(CONFIG_DWMAC_DWC_QOS_ETH)	+= dwmac-dwc-qos-eth.o
> >  obj-$(CONFIG_DWMAC_INTEL_PLAT)	+= dwmac-intel-plat.o
> >  obj-$(CONFIG_DWMAC_GENERIC)	+= dwmac-generic.o
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > new file mode 100644
> > index 000000000000..85135ef05906
> > --- /dev/null
> > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > @@ -0,0 +1,302 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * T-HEAD DWMAC platform driver
> > + *
> > + * Copyright (C) 2021 Alibaba Group Holding Limited.
> > + * Copyright (C) 2023 Jisheng Zhang <jszhang@kernel.org>
> > + *
> > + */
> > +
> > +#include <linux/bitfield.h>
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/of_net.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/regmap.h>
> > +
> > +#include "stmmac_platform.h"
> > +
> > +#define GMAC_CLK_EN			0x00
> > +#define  GMAC_TX_CLK_EN			BIT(1)
> > +#define  GMAC_TX_CLK_N_EN		BIT(2)
> > +#define  GMAC_TX_CLK_OUT_EN		BIT(3)
> > +#define  GMAC_RX_CLK_EN			BIT(4)
> > +#define  GMAC_RX_CLK_N_EN		BIT(5)
> > +#define  GMAC_EPHY_REF_CLK_EN		BIT(6)
> > +#define GMAC_RXCLK_DELAY_CTRL		0x04
> > +#define  GMAC_RXCLK_BYPASS		BIT(15)
> > +#define  GMAC_RXCLK_INVERT		BIT(14)
> > +#define  GMAC_RXCLK_DELAY_MASK		GENMASK(4, 0)
> > +#define  GMAC_RXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > +#define GMAC_TXCLK_DELAY_CTRL		0x08
> > +#define  GMAC_TXCLK_BYPASS		BIT(15)
> > +#define  GMAC_TXCLK_INVERT		BIT(14)
> > +#define  GMAC_TXCLK_DELAY_MASK		GENMASK(4, 0)
> > +#define  GMAC_TXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > +#define GMAC_PLLCLK_DIV			0x0c
> > +#define  GMAC_PLLCLK_DIV_EN		BIT(31)
> > +#define  GMAC_PLLCLK_DIV_MASK		GENMASK(7, 0)
> > +#define  GMAC_PLLCLK_DIV_NUM(x)		FIELD_PREP(GMAC_PLLCLK_DIV_MASK, (x))
> > +#define GMAC_GTXCLK_SEL			0x18
> > +#define  GMAC_GTXCLK_SEL_PLL		BIT(0)
> > +#define GMAC_INTF_CTRL			0x1c
> > +#define  PHY_INTF_MASK			BIT(0)
> > +#define  PHY_INTF_RGMII			FIELD_PREP(PHY_INTF_MASK, 1)
> > +#define  PHY_INTF_MII_GMII		FIELD_PREP(PHY_INTF_MASK, 0)
> > +#define GMAC_TXCLK_OEN			0x20
> > +#define  TXCLK_DIR_MASK			BIT(0)
> > +#define  TXCLK_DIR_OUTPUT		FIELD_PREP(TXCLK_DIR_MASK, 0)
> > +#define  TXCLK_DIR_INPUT		FIELD_PREP(TXCLK_DIR_MASK, 1)
> > +
> > +#define GMAC_GMII_RGMII_RATE	125000000
> > +#define GMAC_MII_RATE		25000000
> > +
> > +struct thead_dwmac {
> > +	struct plat_stmmacenet_data *plat;
> > +	struct regmap *apb_regmap;
> > +	struct device *dev;
> > +	u32 rx_delay;
> > +	u32 tx_delay;
> > +};
> > +
> > +static int thead_dwmac_set_phy_if(struct plat_stmmacenet_data *plat)
> > +{
> > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > +	u32 phyif;
> > +
> > +	switch (plat->interface) {
> > +	case PHY_INTERFACE_MODE_MII:
> > +		phyif = PHY_INTF_MII_GMII;
> > +		break;
> > +	case PHY_INTERFACE_MODE_RGMII:
> > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > +		phyif = PHY_INTF_RGMII;
> > +		break;
> > +	default:
> > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > +			plat->interface);
> > +		return -EINVAL;
> > +	};
> > +
> > +	regmap_write(dwmac->apb_regmap, GMAC_INTF_CTRL, phyif);
> > +
> > +	return 0;
> > +}
> > +
> > +static int thead_dwmac_set_txclk_dir(struct plat_stmmacenet_data *plat)
> > +{
> > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > +	u32 txclk_dir;
> > +
> > +	switch (plat->interface) {
> > +	case PHY_INTERFACE_MODE_MII:
> > +		txclk_dir = TXCLK_DIR_INPUT;
> > +		break;
> > +	case PHY_INTERFACE_MODE_RGMII:
> > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > +		txclk_dir = TXCLK_DIR_OUTPUT;
> > +		break;
> > +	default:
> > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > +			plat->interface);
> > +		return -EINVAL;
> > +	};
> > +
> > +	regmap_write(dwmac->apb_regmap, GMAC_TXCLK_OEN, txclk_dir);
> > +
> > +	return 0;
> > +}
> > +
> > +static void thead_dwmac_fix_speed(void *priv, unsigned int speed, unsigned int mode)
> > +{
> > +	struct thead_dwmac *dwmac = priv;
> > +	struct plat_stmmacenet_data *plat = dwmac->plat;
> > +	unsigned long rate;
> > +	u32 div;
> > +
> > +	switch (plat->interface) {
> > +	/* For MII, rxc/txc is provided by phy */
> > +	case PHY_INTERFACE_MODE_MII:
> > +		return;
> > +
> > +	case PHY_INTERFACE_MODE_RGMII:
> > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> 
> > +		rate = clk_get_rate(plat->stmmac_clk);
> > +		if (!rate || rate % GMAC_GMII_RGMII_RATE != 0 ||
> > +		    rate % GMAC_MII_RATE != 0) {
> > +			dev_err(dwmac->dev, "invalid gmac rate %ld\n", rate);
> > +			return;
> > +		}
> > +
> > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV, GMAC_PLLCLK_DIV_EN, 0);
> > +
> > +		switch (speed) {
> > +		case SPEED_1000:
> > +			div = rate / GMAC_GMII_RGMII_RATE;
> > +			break;
> > +		case SPEED_100:
> > +			div = rate / GMAC_MII_RATE;
> > +			break;
> > +		case SPEED_10:
> > +			div = rate * 10 / GMAC_MII_RATE;
> > +			break;
> > +		default:
> > +			dev_err(dwmac->dev, "invalid speed %u\n", speed);
> > +			return;
> > +		}
> > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > +				   GMAC_PLLCLK_DIV_MASK, GMAC_PLLCLK_DIV_NUM(div));
> > +
> > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > +				   GMAC_PLLCLK_DIV_EN, GMAC_PLLCLK_DIV_EN);
> 
> This chunk looks like a hard-coded implementation of the
> CLK_SET_RATE_GATE Tx-clocks rate setup which parental clock is the
> "stmmaceth" clock. I suggest to move it to the respective driver, add
> a "tx" clock to the bindings and use the common clock kernel API
> methods here only.

I did consider your solution before writing the code, here are the
reasons why I dropped it:

There's no any clk IP here, the HW just puts several
gmac related control bits here, such as rx/tx delay, bypass, invert
interface choice, clk direction. From this point of view, it looks more
like a syscon rather than clk.

Secondly, I see other SoCs did similar for this case, such as
dwmac-visconti, dwmac-meson8b, dwmac-ipq806x, dwmac-socfpga and so on.
They met similar issue as the above.

PS: here is the initial th1520 clk driver, as is seen, the clk IP is
different from the control logic here.

https://lore.kernel.org/linux-riscv/20230515054402.27633-1-frank.li@vivo.com/

Thanks

> 
> > +		break;
> > +	default:
> > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > +			plat->interface);
> > +		return;
> > +	}
> > +}
> > +
> > +static int thead_dwmac_enable_clk(struct plat_stmmacenet_data *plat)
> > +{
> > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > +	u32 reg;
> > +
> > +	switch (plat->interface) {
> > +	case PHY_INTERFACE_MODE_MII:
> > +		reg = GMAC_RX_CLK_EN | GMAC_TX_CLK_EN;
> > +		break;
> > +
> > +	case PHY_INTERFACE_MODE_RGMII:
> > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > +		/* use pll */
> > +		regmap_write(dwmac->apb_regmap, GMAC_GTXCLK_SEL, GMAC_GTXCLK_SEL_PLL);
> > +
> 
> > +		reg = GMAC_TX_CLK_EN | GMAC_TX_CLK_N_EN | GMAC_TX_CLK_OUT_EN |
> > +		      GMAC_RX_CLK_EN | GMAC_RX_CLK_N_EN;
> 
> Similarly settings these flags looks like just clock gates which can
> also be moved to the clock driver.
> 
> > +		break;
> > +
> > +	default:
> > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > +			plat->interface);
> > +		return -EINVAL;
> > +	}
> > +
> > +	regmap_write(dwmac->apb_regmap, GMAC_CLK_EN, reg);
> > +
> > +	return 0;
> > +}
> > +
> > +static int thead_dwmac_init(struct platform_device *pdev,
> > +			    struct plat_stmmacenet_data *plat)
> > +{
> > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > +	int ret;
> > +
> > +	ret = thead_dwmac_set_phy_if(plat);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = thead_dwmac_set_txclk_dir(plat);
> > +	if (ret)
> > +		return ret;
> > +
> > +	regmap_write(dwmac->apb_regmap, GMAC_RXCLK_DELAY_CTRL,
> > +		     GMAC_RXCLK_DELAY_VAL(dwmac->rx_delay));
> > +	regmap_write(dwmac->apb_regmap, GMAC_TXCLK_DELAY_CTRL,
> > +		     GMAC_TXCLK_DELAY_VAL(dwmac->tx_delay));
> > +
> > +	thead_dwmac_fix_speed(dwmac, SPEED_1000, 0);
> > +
> > +	return thead_dwmac_enable_clk(plat);
> > +}
> > +
> > +static int thead_dwmac_probe(struct platform_device *pdev)
> > +{
> > +	struct plat_stmmacenet_data *plat;
> > +	struct stmmac_resources stmmac_res;
> > +	struct thead_dwmac *dwmac;
> > +	struct device_node *np = pdev->dev.of_node;
> > +	u32 delay_ps;
> > +	int ret;
> > +
> > +	ret = stmmac_get_platform_resources(pdev, &stmmac_res);
> > +	if (ret)
> > +		return dev_err_probe(&pdev->dev, ret,
> > +				     "failed to get resources\n");
> > +
> 
> > +	plat = stmmac_probe_config_dt(pdev, stmmac_res.mac);
> 
> This can be replaced with devm_stmmac_probe_config_dt() so the
> stmmac_remove_config_dt() invocation would be dropped.
> 
> > +	if (IS_ERR(plat))
> > +		return dev_err_probe(&pdev->dev, PTR_ERR(plat),
> > +				     "dt configuration failed\n");
> > +
> > +	dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
> > +	if (!dwmac) {
> > +		ret = -ENOMEM;
> > +		goto err_remove_config_dt;
> > +	}
> > +
> > +	if (!of_property_read_u32(np, "rx-internal-delay-ps", &delay_ps))
> > +		dwmac->rx_delay = delay_ps;
> > +	if (!of_property_read_u32(np, "tx-internal-delay-ps", &delay_ps))
> > +		dwmac->tx_delay = delay_ps;
> > +
> > +	dwmac->apb_regmap = syscon_regmap_lookup_by_phandle(np, "thead,gmacapb");
> > +	if (IS_ERR(dwmac->apb_regmap)) {
> > +		ret = dev_err_probe(&pdev->dev, PTR_ERR(dwmac->apb_regmap),
> > +				    "Failed to get gmac apb syscon\n");
> > +		goto err_remove_config_dt;
> > +	}
> > +
> > +	dwmac->dev = &pdev->dev;
> > +	dwmac->plat = plat;
> > +	plat->bsp_priv = dwmac;
> > +	plat->fix_mac_speed = thead_dwmac_fix_speed;
> > +
> 
> > +	ret = thead_dwmac_init(pdev, plat);
> > +	if (ret)
> > +		goto err_remove_config_dt;
> > +
> > +	ret = stmmac_dvr_probe(&pdev->dev, plat, &stmmac_res);
> 
> This can be replaced with:
> plat->init = thead_dwmac_init;
> ret = devm_stmmac_pltfr_probe();
> 
> > +	if (ret)
> > +		goto err_remove_config_dt;
> > +
> > +	return 0;
> > +
> 
> > +err_remove_config_dt:
> > +	stmmac_remove_config_dt(pdev, plat);
> > +
> > +	return ret;
> 
> This can be dropped if devm_stmmac_probe_config_dt() is utilized.
> 
> > +}
> > +
> > +static const struct of_device_id thead_dwmac_match[] = {
> 
> > +	{ .compatible = "thead,th1520-dwmac" },
> 
> See my comment to the bindings about the compatible string suffix.
> 
> > +	{ }
> > +};
> > +MODULE_DEVICE_TABLE(of, thead_dwmac_match);
> > +
> > +static struct platform_driver thead_dwmac_driver = {
> > +	.probe = thead_dwmac_probe,
> 
> > +	.remove_new = stmmac_pltfr_remove,
> 
> This can be dropped if devm_stmmac_probe_config_dt() and
> devm_stmmac_pltfr_probe() are utilized.
> 
> > +	.driver = {
> > +		.name = "thead-dwmac",
> > +		.pm = &stmmac_pltfr_pm_ops,
> > +		.of_match_table = thead_dwmac_match,
> > +	},
> > +};
> > +module_platform_driver(thead_dwmac_driver);
> > +
> > +MODULE_AUTHOR("T-HEAD");
> > +MODULE_AUTHOR("Jisheng Zhang <jszhang@kernel.org>");
> 
> > +MODULE_DESCRIPTION("T-HEAD dwmac platform driver");
>                               ^
>                               |
> Capitalize? ------------------+
> 
> -Serge(y)
> 
> > +MODULE_LICENSE("GPL");
> > -- 
> > 2.40.1
> > 
> >

On Sun, Aug 27, 2023 at 05:17:10PM +0800, Jisheng Zhang wrote:
> Add dwmac glue driver to support the dwmac on the T-HEAD TH1520 SoC.
> 
> Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> ---
>  drivers/net/ethernet/stmicro/stmmac/Kconfig   |  11 +
>  drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
>  .../net/ethernet/stmicro/stmmac/dwmac-thead.c | 302 ++++++++++++++++++
>  3 files changed, 314 insertions(+)
>  create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> index 06c6871f8788..1bf71804c270 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
> +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> @@ -216,6 +216,17 @@ config DWMAC_SUN8I
>  	  stmmac device driver. This driver is used for H3/A83T/A64
>  	  EMAC ethernet controller.
>  
> +config DWMAC_THEAD
> +	tristate "T-HEAD dwmac support"
> +	depends on OF && (ARCH_THEAD || COMPILE_TEST)
> +	select MFD_SYSCON
> +	help
> +	  Support for ethernet controllers on T-HEAD RISC-V SoCs
> +
> +	  This selects the T-HEAD platform specific glue layer support for
> +	  the stmmac device driver. This driver is used for T-HEAD TH1520
> +	  ethernet controller.
> +
>  config DWMAC_IMX8
>  	tristate "NXP IMX8 DWMAC support"
>  	default ARCH_MXC
> diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
> index 5b57aee19267..d73171ed6ad7 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/Makefile
> +++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
> @@ -27,6 +27,7 @@ obj-$(CONFIG_DWMAC_STI)		+= dwmac-sti.o
>  obj-$(CONFIG_DWMAC_STM32)	+= dwmac-stm32.o
>  obj-$(CONFIG_DWMAC_SUNXI)	+= dwmac-sunxi.o
>  obj-$(CONFIG_DWMAC_SUN8I)	+= dwmac-sun8i.o
> +obj-$(CONFIG_DWMAC_THEAD)	+= dwmac-thead.o
>  obj-$(CONFIG_DWMAC_DWC_QOS_ETH)	+= dwmac-dwc-qos-eth.o
>  obj-$(CONFIG_DWMAC_INTEL_PLAT)	+= dwmac-intel-plat.o
>  obj-$(CONFIG_DWMAC_GENERIC)	+= dwmac-generic.o
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> new file mode 100644
> index 000000000000..85135ef05906
> --- /dev/null
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> @@ -0,0 +1,302 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * T-HEAD DWMAC platform driver
> + *
> + * Copyright (C) 2021 Alibaba Group Holding Limited.
> + * Copyright (C) 2023 Jisheng Zhang <jszhang@kernel.org>
> + *
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_net.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#include "stmmac_platform.h"
> +
> +#define GMAC_CLK_EN			0x00
> +#define  GMAC_TX_CLK_EN			BIT(1)
> +#define  GMAC_TX_CLK_N_EN		BIT(2)
> +#define  GMAC_TX_CLK_OUT_EN		BIT(3)
> +#define  GMAC_RX_CLK_EN			BIT(4)
> +#define  GMAC_RX_CLK_N_EN		BIT(5)
> +#define  GMAC_EPHY_REF_CLK_EN		BIT(6)
> +#define GMAC_RXCLK_DELAY_CTRL		0x04
> +#define  GMAC_RXCLK_BYPASS		BIT(15)
> +#define  GMAC_RXCLK_INVERT		BIT(14)
> +#define  GMAC_RXCLK_DELAY_MASK		GENMASK(4, 0)
> +#define  GMAC_RXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> +#define GMAC_TXCLK_DELAY_CTRL		0x08
> +#define  GMAC_TXCLK_BYPASS		BIT(15)
> +#define  GMAC_TXCLK_INVERT		BIT(14)
> +#define  GMAC_TXCLK_DELAY_MASK		GENMASK(4, 0)
> +#define  GMAC_TXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> +#define GMAC_PLLCLK_DIV			0x0c
> +#define  GMAC_PLLCLK_DIV_EN		BIT(31)
> +#define  GMAC_PLLCLK_DIV_MASK		GENMASK(7, 0)
> +#define  GMAC_PLLCLK_DIV_NUM(x)		FIELD_PREP(GMAC_PLLCLK_DIV_MASK, (x))
> +#define GMAC_GTXCLK_SEL			0x18
> +#define  GMAC_GTXCLK_SEL_PLL		BIT(0)
> +#define GMAC_INTF_CTRL			0x1c
> +#define  PHY_INTF_MASK			BIT(0)
> +#define  PHY_INTF_RGMII			FIELD_PREP(PHY_INTF_MASK, 1)
> +#define  PHY_INTF_MII_GMII		FIELD_PREP(PHY_INTF_MASK, 0)
> +#define GMAC_TXCLK_OEN			0x20
> +#define  TXCLK_DIR_MASK			BIT(0)
> +#define  TXCLK_DIR_OUTPUT		FIELD_PREP(TXCLK_DIR_MASK, 0)
> +#define  TXCLK_DIR_INPUT		FIELD_PREP(TXCLK_DIR_MASK, 1)
> +
> +#define GMAC_GMII_RGMII_RATE	125000000
> +#define GMAC_MII_RATE		25000000
> +
> +struct thead_dwmac {
> +	struct plat_stmmacenet_data *plat;
> +	struct regmap *apb_regmap;
> +	struct device *dev;
> +	u32 rx_delay;
> +	u32 tx_delay;
> +};
> +
> +static int thead_dwmac_set_phy_if(struct plat_stmmacenet_data *plat)
> +{
> +	struct thead_dwmac *dwmac = plat->bsp_priv;
> +	u32 phyif;
> +
> +	switch (plat->interface) {
> +	case PHY_INTERFACE_MODE_MII:
> +		phyif = PHY_INTF_MII_GMII;
> +		break;
> +	case PHY_INTERFACE_MODE_RGMII:
> +	case PHY_INTERFACE_MODE_RGMII_ID:
> +	case PHY_INTERFACE_MODE_RGMII_TXID:
> +	case PHY_INTERFACE_MODE_RGMII_RXID:
> +		phyif = PHY_INTF_RGMII;
> +		break;
> +	default:
> +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> +			plat->interface);
> +		return -EINVAL;
> +	};
> +
> +	regmap_write(dwmac->apb_regmap, GMAC_INTF_CTRL, phyif);
> +
> +	return 0;
> +}
> +
> +static int thead_dwmac_set_txclk_dir(struct plat_stmmacenet_data *plat)
> +{
> +	struct thead_dwmac *dwmac = plat->bsp_priv;
> +	u32 txclk_dir;
> +
> +	switch (plat->interface) {
> +	case PHY_INTERFACE_MODE_MII:
> +		txclk_dir = TXCLK_DIR_INPUT;
> +		break;
> +	case PHY_INTERFACE_MODE_RGMII:
> +	case PHY_INTERFACE_MODE_RGMII_ID:
> +	case PHY_INTERFACE_MODE_RGMII_TXID:
> +	case PHY_INTERFACE_MODE_RGMII_RXID:
> +		txclk_dir = TXCLK_DIR_OUTPUT;
> +		break;
> +	default:
> +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> +			plat->interface);
> +		return -EINVAL;
> +	};
> +
> +	regmap_write(dwmac->apb_regmap, GMAC_TXCLK_OEN, txclk_dir);
> +
> +	return 0;
> +}
> +
> +static void thead_dwmac_fix_speed(void *priv, unsigned int speed, unsigned int mode)
> +{
> +	struct thead_dwmac *dwmac = priv;
> +	struct plat_stmmacenet_data *plat = dwmac->plat;
> +	unsigned long rate;
> +	u32 div;
> +
> +	switch (plat->interface) {
> +	/* For MII, rxc/txc is provided by phy */
> +	case PHY_INTERFACE_MODE_MII:
> +		return;
> +
> +	case PHY_INTERFACE_MODE_RGMII:
> +	case PHY_INTERFACE_MODE_RGMII_ID:
> +	case PHY_INTERFACE_MODE_RGMII_RXID:
> +	case PHY_INTERFACE_MODE_RGMII_TXID:
> +		rate = clk_get_rate(plat->stmmac_clk);
> +		if (!rate || rate % GMAC_GMII_RGMII_RATE != 0 ||
> +		    rate % GMAC_MII_RATE != 0) {
> +			dev_err(dwmac->dev, "invalid gmac rate %ld\n", rate);
> +			return;
> +		}
> +
> +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV, GMAC_PLLCLK_DIV_EN, 0);
> +
> +		switch (speed) {
> +		case SPEED_1000:
> +			div = rate / GMAC_GMII_RGMII_RATE;
> +			break;
> +		case SPEED_100:
> +			div = rate / GMAC_MII_RATE;
> +			break;
> +		case SPEED_10:
> +			div = rate * 10 / GMAC_MII_RATE;
> +			break;
> +		default:
> +			dev_err(dwmac->dev, "invalid speed %u\n", speed);
> +			return;
> +		}
> +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> +				   GMAC_PLLCLK_DIV_MASK, GMAC_PLLCLK_DIV_NUM(div));
> +
> +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> +				   GMAC_PLLCLK_DIV_EN, GMAC_PLLCLK_DIV_EN);
> +		break;
> +	default:
> +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> +			plat->interface);
> +		return;
> +	}
> +}
> +
> +static int thead_dwmac_enable_clk(struct plat_stmmacenet_data *plat)
> +{
> +	struct thead_dwmac *dwmac = plat->bsp_priv;
> +	u32 reg;
> +
> +	switch (plat->interface) {
> +	case PHY_INTERFACE_MODE_MII:
> +		reg = GMAC_RX_CLK_EN | GMAC_TX_CLK_EN;
> +		break;
> +
> +	case PHY_INTERFACE_MODE_RGMII:
> +	case PHY_INTERFACE_MODE_RGMII_ID:
> +	case PHY_INTERFACE_MODE_RGMII_RXID:
> +	case PHY_INTERFACE_MODE_RGMII_TXID:
> +		/* use pll */
> +		regmap_write(dwmac->apb_regmap, GMAC_GTXCLK_SEL, GMAC_GTXCLK_SEL_PLL);
> +
> +		reg = GMAC_TX_CLK_EN | GMAC_TX_CLK_N_EN | GMAC_TX_CLK_OUT_EN |
> +		      GMAC_RX_CLK_EN | GMAC_RX_CLK_N_EN;
> +		break;
> +
> +	default:
> +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> +			plat->interface);
> +		return -EINVAL;
> +	}
> +
> +	regmap_write(dwmac->apb_regmap, GMAC_CLK_EN, reg);
> +
> +	return 0;
> +}
> +
> +static int thead_dwmac_init(struct platform_device *pdev,
> +			    struct plat_stmmacenet_data *plat)
> +{
> +	struct thead_dwmac *dwmac = plat->bsp_priv;
> +	int ret;
> +
> +	ret = thead_dwmac_set_phy_if(plat);
> +	if (ret)
> +		return ret;
> +
> +	ret = thead_dwmac_set_txclk_dir(plat);
> +	if (ret)
> +		return ret;
> +

> +	regmap_write(dwmac->apb_regmap, GMAC_RXCLK_DELAY_CTRL,
> +		     GMAC_RXCLK_DELAY_VAL(dwmac->rx_delay));
> +	regmap_write(dwmac->apb_regmap, GMAC_TXCLK_DELAY_CTRL,
> +		     GMAC_TXCLK_DELAY_VAL(dwmac->tx_delay));

Just noticed. This doesn't look right because:
1. Are you sure your hardware expects the delays being specified in
picoseconds. It's most likely a number of reference clock cycles and
thus the DT-properties values should be properly converted.
2. Both delays should be added only for "rgmii" phy-mode, Tx clock
delay - for "rgmii-rxid" phy-mode, Rx clock delay - for "rgmii-txid"
phy-mode.

-Serge(y)

> +
> +	thead_dwmac_fix_speed(dwmac, SPEED_1000, 0);
> +
> +	return thead_dwmac_enable_clk(plat);
> +}
> +
> +static int thead_dwmac_probe(struct platform_device *pdev)
> +{
> +	struct plat_stmmacenet_data *plat;
> +	struct stmmac_resources stmmac_res;
> +	struct thead_dwmac *dwmac;
> +	struct device_node *np = pdev->dev.of_node;
> +	u32 delay_ps;
> +	int ret;
> +
> +	ret = stmmac_get_platform_resources(pdev, &stmmac_res);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret,
> +				     "failed to get resources\n");
> +
> +	plat = stmmac_probe_config_dt(pdev, stmmac_res.mac);
> +	if (IS_ERR(plat))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(plat),
> +				     "dt configuration failed\n");
> +
> +	dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
> +	if (!dwmac) {
> +		ret = -ENOMEM;
> +		goto err_remove_config_dt;
> +	}
> +
> +	if (!of_property_read_u32(np, "rx-internal-delay-ps", &delay_ps))
> +		dwmac->rx_delay = delay_ps;
> +	if (!of_property_read_u32(np, "tx-internal-delay-ps", &delay_ps))
> +		dwmac->tx_delay = delay_ps;
> +
> +	dwmac->apb_regmap = syscon_regmap_lookup_by_phandle(np, "thead,gmacapb");
> +	if (IS_ERR(dwmac->apb_regmap)) {
> +		ret = dev_err_probe(&pdev->dev, PTR_ERR(dwmac->apb_regmap),
> +				    "Failed to get gmac apb syscon\n");
> +		goto err_remove_config_dt;
> +	}
> +
> +	dwmac->dev = &pdev->dev;
> +	dwmac->plat = plat;
> +	plat->bsp_priv = dwmac;
> +	plat->fix_mac_speed = thead_dwmac_fix_speed;
> +
> +	ret = thead_dwmac_init(pdev, plat);
> +	if (ret)
> +		goto err_remove_config_dt;
> +
> +	ret = stmmac_dvr_probe(&pdev->dev, plat, &stmmac_res);
> +	if (ret)
> +		goto err_remove_config_dt;
> +
> +	return 0;
> +
> +err_remove_config_dt:
> +	stmmac_remove_config_dt(pdev, plat);
> +
> +	return ret;
> +}
> +
> +static const struct of_device_id thead_dwmac_match[] = {
> +	{ .compatible = "thead,th1520-dwmac" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, thead_dwmac_match);
> +
> +static struct platform_driver thead_dwmac_driver = {
> +	.probe = thead_dwmac_probe,
> +	.remove_new = stmmac_pltfr_remove,
> +	.driver = {
> +		.name = "thead-dwmac",
> +		.pm = &stmmac_pltfr_pm_ops,
> +		.of_match_table = thead_dwmac_match,
> +	},
> +};
> +module_platform_driver(thead_dwmac_driver);
> +
> +MODULE_AUTHOR("T-HEAD");
> +MODULE_AUTHOR("Jisheng Zhang <jszhang@kernel.org>");
> +MODULE_DESCRIPTION("T-HEAD dwmac platform driver");
> +MODULE_LICENSE("GPL");
> -- 
> 2.40.1
> 
>

On Mon, Aug 28, 2023 at 06:58:11PM +0300, Serge Semin wrote:
> On Sun, Aug 27, 2023 at 05:17:10PM +0800, Jisheng Zhang wrote:
> > Add dwmac glue driver to support the dwmac on the T-HEAD TH1520 SoC.
> > 
> > Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> > ---
> >  drivers/net/ethernet/stmicro/stmmac/Kconfig   |  11 +
> >  drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
> >  .../net/ethernet/stmicro/stmmac/dwmac-thead.c | 302 ++++++++++++++++++
> >  3 files changed, 314 insertions(+)
> >  create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > 
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > index 06c6871f8788..1bf71804c270 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > @@ -216,6 +216,17 @@ config DWMAC_SUN8I
> >  	  stmmac device driver. This driver is used for H3/A83T/A64
> >  	  EMAC ethernet controller.
> >  
> > +config DWMAC_THEAD
> > +	tristate "T-HEAD dwmac support"
> > +	depends on OF && (ARCH_THEAD || COMPILE_TEST)
> > +	select MFD_SYSCON
> > +	help
> > +	  Support for ethernet controllers on T-HEAD RISC-V SoCs
> > +
> > +	  This selects the T-HEAD platform specific glue layer support for
> > +	  the stmmac device driver. This driver is used for T-HEAD TH1520
> > +	  ethernet controller.
> > +
> >  config DWMAC_IMX8
> >  	tristate "NXP IMX8 DWMAC support"
> >  	default ARCH_MXC
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > index 5b57aee19267..d73171ed6ad7 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/Makefile
> > +++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > @@ -27,6 +27,7 @@ obj-$(CONFIG_DWMAC_STI)		+= dwmac-sti.o
> >  obj-$(CONFIG_DWMAC_STM32)	+= dwmac-stm32.o
> >  obj-$(CONFIG_DWMAC_SUNXI)	+= dwmac-sunxi.o
> >  obj-$(CONFIG_DWMAC_SUN8I)	+= dwmac-sun8i.o
> > +obj-$(CONFIG_DWMAC_THEAD)	+= dwmac-thead.o
> >  obj-$(CONFIG_DWMAC_DWC_QOS_ETH)	+= dwmac-dwc-qos-eth.o
> >  obj-$(CONFIG_DWMAC_INTEL_PLAT)	+= dwmac-intel-plat.o
> >  obj-$(CONFIG_DWMAC_GENERIC)	+= dwmac-generic.o
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > new file mode 100644
> > index 000000000000..85135ef05906
> > --- /dev/null
> > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > @@ -0,0 +1,302 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * T-HEAD DWMAC platform driver
> > + *
> > + * Copyright (C) 2021 Alibaba Group Holding Limited.
> > + * Copyright (C) 2023 Jisheng Zhang <jszhang@kernel.org>
> > + *
> > + */
> > +
> > +#include <linux/bitfield.h>
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/of_net.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/regmap.h>
> > +
> > +#include "stmmac_platform.h"
> > +
> > +#define GMAC_CLK_EN			0x00
> > +#define  GMAC_TX_CLK_EN			BIT(1)
> > +#define  GMAC_TX_CLK_N_EN		BIT(2)
> > +#define  GMAC_TX_CLK_OUT_EN		BIT(3)
> > +#define  GMAC_RX_CLK_EN			BIT(4)
> > +#define  GMAC_RX_CLK_N_EN		BIT(5)
> > +#define  GMAC_EPHY_REF_CLK_EN		BIT(6)
> > +#define GMAC_RXCLK_DELAY_CTRL		0x04
> > +#define  GMAC_RXCLK_BYPASS		BIT(15)
> > +#define  GMAC_RXCLK_INVERT		BIT(14)
> > +#define  GMAC_RXCLK_DELAY_MASK		GENMASK(4, 0)
> > +#define  GMAC_RXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > +#define GMAC_TXCLK_DELAY_CTRL		0x08
> > +#define  GMAC_TXCLK_BYPASS		BIT(15)
> > +#define  GMAC_TXCLK_INVERT		BIT(14)
> > +#define  GMAC_TXCLK_DELAY_MASK		GENMASK(4, 0)
> > +#define  GMAC_TXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > +#define GMAC_PLLCLK_DIV			0x0c
> > +#define  GMAC_PLLCLK_DIV_EN		BIT(31)
> > +#define  GMAC_PLLCLK_DIV_MASK		GENMASK(7, 0)
> > +#define  GMAC_PLLCLK_DIV_NUM(x)		FIELD_PREP(GMAC_PLLCLK_DIV_MASK, (x))
> > +#define GMAC_GTXCLK_SEL			0x18
> > +#define  GMAC_GTXCLK_SEL_PLL		BIT(0)
> > +#define GMAC_INTF_CTRL			0x1c
> > +#define  PHY_INTF_MASK			BIT(0)
> > +#define  PHY_INTF_RGMII			FIELD_PREP(PHY_INTF_MASK, 1)
> > +#define  PHY_INTF_MII_GMII		FIELD_PREP(PHY_INTF_MASK, 0)
> > +#define GMAC_TXCLK_OEN			0x20
> > +#define  TXCLK_DIR_MASK			BIT(0)
> > +#define  TXCLK_DIR_OUTPUT		FIELD_PREP(TXCLK_DIR_MASK, 0)
> > +#define  TXCLK_DIR_INPUT		FIELD_PREP(TXCLK_DIR_MASK, 1)
> > +
> > +#define GMAC_GMII_RGMII_RATE	125000000
> > +#define GMAC_MII_RATE		25000000
> > +
> > +struct thead_dwmac {
> > +	struct plat_stmmacenet_data *plat;
> > +	struct regmap *apb_regmap;
> > +	struct device *dev;
> > +	u32 rx_delay;
> > +	u32 tx_delay;
> > +};
> > +
> > +static int thead_dwmac_set_phy_if(struct plat_stmmacenet_data *plat)
> > +{
> > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > +	u32 phyif;
> > +
> > +	switch (plat->interface) {
> > +	case PHY_INTERFACE_MODE_MII:
> > +		phyif = PHY_INTF_MII_GMII;
> > +		break;
> > +	case PHY_INTERFACE_MODE_RGMII:
> > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > +		phyif = PHY_INTF_RGMII;
> > +		break;
> > +	default:
> > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > +			plat->interface);
> > +		return -EINVAL;
> > +	};
> > +
> > +	regmap_write(dwmac->apb_regmap, GMAC_INTF_CTRL, phyif);
> > +
> > +	return 0;
> > +}
> > +
> > +static int thead_dwmac_set_txclk_dir(struct plat_stmmacenet_data *plat)
> > +{
> > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > +	u32 txclk_dir;
> > +
> > +	switch (plat->interface) {
> > +	case PHY_INTERFACE_MODE_MII:
> > +		txclk_dir = TXCLK_DIR_INPUT;
> > +		break;
> > +	case PHY_INTERFACE_MODE_RGMII:
> > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > +		txclk_dir = TXCLK_DIR_OUTPUT;
> > +		break;
> > +	default:
> > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > +			plat->interface);
> > +		return -EINVAL;
> > +	};
> > +
> > +	regmap_write(dwmac->apb_regmap, GMAC_TXCLK_OEN, txclk_dir);
> > +
> > +	return 0;
> > +}
> > +
> > +static void thead_dwmac_fix_speed(void *priv, unsigned int speed, unsigned int mode)
> > +{
> > +	struct thead_dwmac *dwmac = priv;
> > +	struct plat_stmmacenet_data *plat = dwmac->plat;
> > +	unsigned long rate;
> > +	u32 div;
> > +
> > +	switch (plat->interface) {
> > +	/* For MII, rxc/txc is provided by phy */
> > +	case PHY_INTERFACE_MODE_MII:
> > +		return;
> > +
> > +	case PHY_INTERFACE_MODE_RGMII:
> > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > +		rate = clk_get_rate(plat->stmmac_clk);
> > +		if (!rate || rate % GMAC_GMII_RGMII_RATE != 0 ||
> > +		    rate % GMAC_MII_RATE != 0) {
> > +			dev_err(dwmac->dev, "invalid gmac rate %ld\n", rate);
> > +			return;
> > +		}
> > +
> > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV, GMAC_PLLCLK_DIV_EN, 0);
> > +
> > +		switch (speed) {
> > +		case SPEED_1000:
> > +			div = rate / GMAC_GMII_RGMII_RATE;
> > +			break;
> > +		case SPEED_100:
> > +			div = rate / GMAC_MII_RATE;
> > +			break;
> > +		case SPEED_10:
> > +			div = rate * 10 / GMAC_MII_RATE;
> > +			break;
> > +		default:
> > +			dev_err(dwmac->dev, "invalid speed %u\n", speed);
> > +			return;
> > +		}
> > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > +				   GMAC_PLLCLK_DIV_MASK, GMAC_PLLCLK_DIV_NUM(div));
> > +
> > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > +				   GMAC_PLLCLK_DIV_EN, GMAC_PLLCLK_DIV_EN);
> > +		break;
> > +	default:
> > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > +			plat->interface);
> > +		return;
> > +	}
> > +}
> > +
> > +static int thead_dwmac_enable_clk(struct plat_stmmacenet_data *plat)
> > +{
> > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > +	u32 reg;
> > +
> > +	switch (plat->interface) {
> > +	case PHY_INTERFACE_MODE_MII:
> > +		reg = GMAC_RX_CLK_EN | GMAC_TX_CLK_EN;
> > +		break;
> > +
> > +	case PHY_INTERFACE_MODE_RGMII:
> > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > +		/* use pll */
> > +		regmap_write(dwmac->apb_regmap, GMAC_GTXCLK_SEL, GMAC_GTXCLK_SEL_PLL);
> > +
> > +		reg = GMAC_TX_CLK_EN | GMAC_TX_CLK_N_EN | GMAC_TX_CLK_OUT_EN |
> > +		      GMAC_RX_CLK_EN | GMAC_RX_CLK_N_EN;
> > +		break;
> > +
> > +	default:
> > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > +			plat->interface);
> > +		return -EINVAL;
> > +	}
> > +
> > +	regmap_write(dwmac->apb_regmap, GMAC_CLK_EN, reg);
> > +
> > +	return 0;
> > +}
> > +
> > +static int thead_dwmac_init(struct platform_device *pdev,
> > +			    struct plat_stmmacenet_data *plat)
> > +{
> > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > +	int ret;
> > +
> > +	ret = thead_dwmac_set_phy_if(plat);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = thead_dwmac_set_txclk_dir(plat);
> > +	if (ret)
> > +		return ret;
> > +
> 
> > +	regmap_write(dwmac->apb_regmap, GMAC_RXCLK_DELAY_CTRL,
> > +		     GMAC_RXCLK_DELAY_VAL(dwmac->rx_delay));
> > +	regmap_write(dwmac->apb_regmap, GMAC_TXCLK_DELAY_CTRL,
> > +		     GMAC_TXCLK_DELAY_VAL(dwmac->tx_delay));
> 
> Just noticed. This doesn't look right because:
> 1. Are you sure your hardware expects the delays being specified in
> picoseconds. It's most likely a number of reference clock cycles and
> thus the DT-properties values should be properly converted.

Good catch! I need to check further.
> 2. Both delays should be added only for "rgmii" phy-mode, Tx clock
> delay - for "rgmii-rxid" phy-mode, Rx clock delay - for "rgmii-txid"
> phy-mode.

For MII, the rxc/txc is provided by phy, so setting those delays
won't impact MII.
> 
> -Serge(y)
> 
> > +
> > +	thead_dwmac_fix_speed(dwmac, SPEED_1000, 0);
> > +
> > +	return thead_dwmac_enable_clk(plat);
> > +}
> > +
> > +static int thead_dwmac_probe(struct platform_device *pdev)
> > +{
> > +	struct plat_stmmacenet_data *plat;
> > +	struct stmmac_resources stmmac_res;
> > +	struct thead_dwmac *dwmac;
> > +	struct device_node *np = pdev->dev.of_node;
> > +	u32 delay_ps;
> > +	int ret;
> > +
> > +	ret = stmmac_get_platform_resources(pdev, &stmmac_res);
> > +	if (ret)
> > +		return dev_err_probe(&pdev->dev, ret,
> > +				     "failed to get resources\n");
> > +
> > +	plat = stmmac_probe_config_dt(pdev, stmmac_res.mac);
> > +	if (IS_ERR(plat))
> > +		return dev_err_probe(&pdev->dev, PTR_ERR(plat),
> > +				     "dt configuration failed\n");
> > +
> > +	dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
> > +	if (!dwmac) {
> > +		ret = -ENOMEM;
> > +		goto err_remove_config_dt;
> > +	}
> > +
> > +	if (!of_property_read_u32(np, "rx-internal-delay-ps", &delay_ps))
> > +		dwmac->rx_delay = delay_ps;
> > +	if (!of_property_read_u32(np, "tx-internal-delay-ps", &delay_ps))
> > +		dwmac->tx_delay = delay_ps;
> > +
> > +	dwmac->apb_regmap = syscon_regmap_lookup_by_phandle(np, "thead,gmacapb");
> > +	if (IS_ERR(dwmac->apb_regmap)) {
> > +		ret = dev_err_probe(&pdev->dev, PTR_ERR(dwmac->apb_regmap),
> > +				    "Failed to get gmac apb syscon\n");
> > +		goto err_remove_config_dt;
> > +	}
> > +
> > +	dwmac->dev = &pdev->dev;
> > +	dwmac->plat = plat;
> > +	plat->bsp_priv = dwmac;
> > +	plat->fix_mac_speed = thead_dwmac_fix_speed;
> > +
> > +	ret = thead_dwmac_init(pdev, plat);
> > +	if (ret)
> > +		goto err_remove_config_dt;
> > +
> > +	ret = stmmac_dvr_probe(&pdev->dev, plat, &stmmac_res);
> > +	if (ret)
> > +		goto err_remove_config_dt;
> > +
> > +	return 0;
> > +
> > +err_remove_config_dt:
> > +	stmmac_remove_config_dt(pdev, plat);
> > +
> > +	return ret;
> > +}
> > +
> > +static const struct of_device_id thead_dwmac_match[] = {
> > +	{ .compatible = "thead,th1520-dwmac" },
> > +	{ }
> > +};
> > +MODULE_DEVICE_TABLE(of, thead_dwmac_match);
> > +
> > +static struct platform_driver thead_dwmac_driver = {
> > +	.probe = thead_dwmac_probe,
> > +	.remove_new = stmmac_pltfr_remove,
> > +	.driver = {
> > +		.name = "thead-dwmac",
> > +		.pm = &stmmac_pltfr_pm_ops,
> > +		.of_match_table = thead_dwmac_match,
> > +	},
> > +};
> > +module_platform_driver(thead_dwmac_driver);
> > +
> > +MODULE_AUTHOR("T-HEAD");
> > +MODULE_AUTHOR("Jisheng Zhang <jszhang@kernel.org>");
> > +MODULE_DESCRIPTION("T-HEAD dwmac platform driver");
> > +MODULE_LICENSE("GPL");
> > -- 
> > 2.40.1
> > 
> >

On Mon, 28 Aug 2023 at 17:55, Jisheng Zhang <jszhang@kernel.org> wrote:
> On Mon, Aug 28, 2023 at 04:40:19PM +0300, Serge Semin wrote:
> > On Sun, Aug 27, 2023 at 05:17:10PM +0800, Jisheng Zhang wrote:
> > > Add dwmac glue driver to support the dwmac on the T-HEAD TH1520 SoC.
> > >
> > > Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> > > ---
> > >  drivers/net/ethernet/stmicro/stmmac/Kconfig   |  11 +
> > >  drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
> > >  .../net/ethernet/stmicro/stmmac/dwmac-thead.c | 302 ++++++++++++++++++
> > >  3 files changed, 314 insertions(+)
> > >  create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > >
> > > diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > index 06c6871f8788..1bf71804c270 100644
> > > --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > @@ -216,6 +216,17 @@ config DWMAC_SUN8I
> > >       stmmac device driver. This driver is used for H3/A83T/A64
> > >       EMAC ethernet controller.
> > >
> > > +config DWMAC_THEAD
> > > +   tristate "T-HEAD dwmac support"
> > > +   depends on OF && (ARCH_THEAD || COMPILE_TEST)
> > > +   select MFD_SYSCON
> > > +   help
> > > +     Support for ethernet controllers on T-HEAD RISC-V SoCs
> > > +
> > > +     This selects the T-HEAD platform specific glue layer support for
> > > +     the stmmac device driver. This driver is used for T-HEAD TH1520
> > > +     ethernet controller.
> > > +
> > >  config DWMAC_IMX8
> > >     tristate "NXP IMX8 DWMAC support"
> > >     default ARCH_MXC
> > > diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > index 5b57aee19267..d73171ed6ad7 100644
> > > --- a/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > +++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > @@ -27,6 +27,7 @@ obj-$(CONFIG_DWMAC_STI)           += dwmac-sti.o
> > >  obj-$(CONFIG_DWMAC_STM32)  += dwmac-stm32.o
> > >  obj-$(CONFIG_DWMAC_SUNXI)  += dwmac-sunxi.o
> > >  obj-$(CONFIG_DWMAC_SUN8I)  += dwmac-sun8i.o
> > > +obj-$(CONFIG_DWMAC_THEAD)  += dwmac-thead.o
> > >  obj-$(CONFIG_DWMAC_DWC_QOS_ETH)    += dwmac-dwc-qos-eth.o
> > >  obj-$(CONFIG_DWMAC_INTEL_PLAT)     += dwmac-intel-plat.o
> > >  obj-$(CONFIG_DWMAC_GENERIC)        += dwmac-generic.o
> > > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > > new file mode 100644
> > > index 000000000000..85135ef05906
> > > --- /dev/null
> > > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > > @@ -0,0 +1,302 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * T-HEAD DWMAC platform driver
> > > + *
> > > + * Copyright (C) 2021 Alibaba Group Holding Limited.
> > > + * Copyright (C) 2023 Jisheng Zhang <jszhang@kernel.org>
> > > + *
> > > + */
> > > +
> > > +#include <linux/bitfield.h>
> > > +#include <linux/mfd/syscon.h>
> > > +#include <linux/module.h>
> > > +#include <linux/of.h>
> > > +#include <linux/of_device.h>
> > > +#include <linux/of_net.h>
> > > +#include <linux/platform_device.h>
> > > +#include <linux/regmap.h>
> > > +
> > > +#include "stmmac_platform.h"
> > > +
> > > +#define GMAC_CLK_EN                        0x00
> > > +#define  GMAC_TX_CLK_EN                    BIT(1)
> > > +#define  GMAC_TX_CLK_N_EN          BIT(2)
> > > +#define  GMAC_TX_CLK_OUT_EN                BIT(3)
> > > +#define  GMAC_RX_CLK_EN                    BIT(4)
> > > +#define  GMAC_RX_CLK_N_EN          BIT(5)
> > > +#define  GMAC_EPHY_REF_CLK_EN              BIT(6)
> > > +#define GMAC_RXCLK_DELAY_CTRL              0x04
> > > +#define  GMAC_RXCLK_BYPASS         BIT(15)
> > > +#define  GMAC_RXCLK_INVERT         BIT(14)
> > > +#define  GMAC_RXCLK_DELAY_MASK             GENMASK(4, 0)
> > > +#define  GMAC_RXCLK_DELAY_VAL(x)   FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > > +#define GMAC_TXCLK_DELAY_CTRL              0x08
> > > +#define  GMAC_TXCLK_BYPASS         BIT(15)
> > > +#define  GMAC_TXCLK_INVERT         BIT(14)
> > > +#define  GMAC_TXCLK_DELAY_MASK             GENMASK(4, 0)
> > > +#define  GMAC_TXCLK_DELAY_VAL(x)   FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > > +#define GMAC_PLLCLK_DIV                    0x0c
> > > +#define  GMAC_PLLCLK_DIV_EN                BIT(31)
> > > +#define  GMAC_PLLCLK_DIV_MASK              GENMASK(7, 0)
> > > +#define  GMAC_PLLCLK_DIV_NUM(x)            FIELD_PREP(GMAC_PLLCLK_DIV_MASK, (x))
> > > +#define GMAC_GTXCLK_SEL                    0x18
> > > +#define  GMAC_GTXCLK_SEL_PLL               BIT(0)
> > > +#define GMAC_INTF_CTRL                     0x1c
> > > +#define  PHY_INTF_MASK                     BIT(0)
> > > +#define  PHY_INTF_RGMII                    FIELD_PREP(PHY_INTF_MASK, 1)
> > > +#define  PHY_INTF_MII_GMII         FIELD_PREP(PHY_INTF_MASK, 0)
> > > +#define GMAC_TXCLK_OEN                     0x20
> > > +#define  TXCLK_DIR_MASK                    BIT(0)
> > > +#define  TXCLK_DIR_OUTPUT          FIELD_PREP(TXCLK_DIR_MASK, 0)
> > > +#define  TXCLK_DIR_INPUT           FIELD_PREP(TXCLK_DIR_MASK, 1)
> > > +
> > > +#define GMAC_GMII_RGMII_RATE       125000000
> > > +#define GMAC_MII_RATE              25000000
> > > +
> > > +struct thead_dwmac {
> > > +   struct plat_stmmacenet_data *plat;
> > > +   struct regmap *apb_regmap;
> > > +   struct device *dev;
> > > +   u32 rx_delay;
> > > +   u32 tx_delay;
> > > +};
> > > +
> > > +static int thead_dwmac_set_phy_if(struct plat_stmmacenet_data *plat)
> > > +{
> > > +   struct thead_dwmac *dwmac = plat->bsp_priv;
> > > +   u32 phyif;
> > > +
> > > +   switch (plat->interface) {
> > > +   case PHY_INTERFACE_MODE_MII:
> > > +           phyif = PHY_INTF_MII_GMII;
> > > +           break;
> > > +   case PHY_INTERFACE_MODE_RGMII:
> > > +   case PHY_INTERFACE_MODE_RGMII_ID:
> > > +   case PHY_INTERFACE_MODE_RGMII_TXID:
> > > +   case PHY_INTERFACE_MODE_RGMII_RXID:
> > > +           phyif = PHY_INTF_RGMII;
> > > +           break;
> > > +   default:
> > > +           dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > +                   plat->interface);
> > > +           return -EINVAL;
> > > +   };
> > > +
> > > +   regmap_write(dwmac->apb_regmap, GMAC_INTF_CTRL, phyif);
> > > +
> > > +   return 0;
> > > +}
> > > +
> > > +static int thead_dwmac_set_txclk_dir(struct plat_stmmacenet_data *plat)
> > > +{
> > > +   struct thead_dwmac *dwmac = plat->bsp_priv;
> > > +   u32 txclk_dir;
> > > +
> > > +   switch (plat->interface) {
> > > +   case PHY_INTERFACE_MODE_MII:
> > > +           txclk_dir = TXCLK_DIR_INPUT;
> > > +           break;
> > > +   case PHY_INTERFACE_MODE_RGMII:
> > > +   case PHY_INTERFACE_MODE_RGMII_ID:
> > > +   case PHY_INTERFACE_MODE_RGMII_TXID:
> > > +   case PHY_INTERFACE_MODE_RGMII_RXID:
> > > +           txclk_dir = TXCLK_DIR_OUTPUT;
> > > +           break;
> > > +   default:
> > > +           dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > +                   plat->interface);
> > > +           return -EINVAL;
> > > +   };
> > > +
> > > +   regmap_write(dwmac->apb_regmap, GMAC_TXCLK_OEN, txclk_dir);
> > > +
> > > +   return 0;
> > > +}
> > > +
> > > +static void thead_dwmac_fix_speed(void *priv, unsigned int speed, unsigned int mode)
> > > +{
> > > +   struct thead_dwmac *dwmac = priv;
> > > +   struct plat_stmmacenet_data *plat = dwmac->plat;
> > > +   unsigned long rate;
> > > +   u32 div;
> > > +
> > > +   switch (plat->interface) {
> > > +   /* For MII, rxc/txc is provided by phy */
> > > +   case PHY_INTERFACE_MODE_MII:
> > > +           return;
> > > +
> > > +   case PHY_INTERFACE_MODE_RGMII:
> > > +   case PHY_INTERFACE_MODE_RGMII_ID:
> > > +   case PHY_INTERFACE_MODE_RGMII_RXID:
> > > +   case PHY_INTERFACE_MODE_RGMII_TXID:
> >
> > > +           rate = clk_get_rate(plat->stmmac_clk);
> > > +           if (!rate || rate % GMAC_GMII_RGMII_RATE != 0 ||
> > > +               rate % GMAC_MII_RATE != 0) {
> > > +                   dev_err(dwmac->dev, "invalid gmac rate %ld\n", rate);
> > > +                   return;
> > > +           }
> > > +
> > > +           regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV, GMAC_PLLCLK_DIV_EN, 0);
> > > +
> > > +           switch (speed) {
> > > +           case SPEED_1000:
> > > +                   div = rate / GMAC_GMII_RGMII_RATE;
> > > +                   break;
> > > +           case SPEED_100:
> > > +                   div = rate / GMAC_MII_RATE;
> > > +                   break;
> > > +           case SPEED_10:
> > > +                   div = rate * 10 / GMAC_MII_RATE;
> > > +                   break;
> > > +           default:
> > > +                   dev_err(dwmac->dev, "invalid speed %u\n", speed);
> > > +                   return;
> > > +           }
> > > +           regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > > +                              GMAC_PLLCLK_DIV_MASK, GMAC_PLLCLK_DIV_NUM(div));
> > > +
> > > +           regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > > +                              GMAC_PLLCLK_DIV_EN, GMAC_PLLCLK_DIV_EN);
> >
> > This chunk looks like a hard-coded implementation of the
> > CLK_SET_RATE_GATE Tx-clocks rate setup which parental clock is the
> > "stmmaceth" clock. I suggest to move it to the respective driver, add
> > a "tx" clock to the bindings and use the common clock kernel API
> > methods here only.
>
> I did consider your solution before writing the code, here are the
> reasons why I dropped it:
>
> There's no any clk IP here, the HW just puts several
> gmac related control bits here, such as rx/tx delay, bypass, invert
> interface choice, clk direction. From this point of view, it looks more
> like a syscon rather than clk.

Hi Jisheng.

That's not really a compelling argument to do the clock manipulation
here. Look at the StarFive JH7110 PLL clock driver. It's exactly a
clock driver for just the registers controlling the PLLs among the
other syscon registers.

> Secondly, I see other SoCs did similar for this case, such as
> dwmac-visconti, dwmac-meson8b, dwmac-ipq806x, dwmac-socfpga and so on.
> They met similar issue as the above.
>
> PS: here is the initial th1520 clk driver, as is seen, the clk IP is
> different from the control logic here.
>
> https://lore.kernel.org/linux-riscv/20230515054402.27633-1-frank.li@vivo.com/
>
> Thanks
>
> >
> > > +           break;
> > > +   default:
> > > +           dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > +                   plat->interface);
> > > +           return;
> > > +   }
> > > +}
> > > +
> > > +static int thead_dwmac_enable_clk(struct plat_stmmacenet_data *plat)
> > > +{
> > > +   struct thead_dwmac *dwmac = plat->bsp_priv;
> > > +   u32 reg;
> > > +
> > > +   switch (plat->interface) {
> > > +   case PHY_INTERFACE_MODE_MII:
> > > +           reg = GMAC_RX_CLK_EN | GMAC_TX_CLK_EN;
> > > +           break;
> > > +
> > > +   case PHY_INTERFACE_MODE_RGMII:
> > > +   case PHY_INTERFACE_MODE_RGMII_ID:
> > > +   case PHY_INTERFACE_MODE_RGMII_RXID:
> > > +   case PHY_INTERFACE_MODE_RGMII_TXID:
> > > +           /* use pll */
> > > +           regmap_write(dwmac->apb_regmap, GMAC_GTXCLK_SEL, GMAC_GTXCLK_SEL_PLL);
> > > +
> >
> > > +           reg = GMAC_TX_CLK_EN | GMAC_TX_CLK_N_EN | GMAC_TX_CLK_OUT_EN |
> > > +                 GMAC_RX_CLK_EN | GMAC_RX_CLK_N_EN;
> >
> > Similarly settings these flags looks like just clock gates which can
> > also be moved to the clock driver.
> >
> > > +           break;
> > > +
> > > +   default:
> > > +           dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > +                   plat->interface);
> > > +           return -EINVAL;
> > > +   }
> > > +
> > > +   regmap_write(dwmac->apb_regmap, GMAC_CLK_EN, reg);
> > > +
> > > +   return 0;
> > > +}
> > > +
> > > +static int thead_dwmac_init(struct platform_device *pdev,
> > > +                       struct plat_stmmacenet_data *plat)
> > > +{
> > > +   struct thead_dwmac *dwmac = plat->bsp_priv;
> > > +   int ret;
> > > +
> > > +   ret = thead_dwmac_set_phy_if(plat);
> > > +   if (ret)
> > > +           return ret;
> > > +
> > > +   ret = thead_dwmac_set_txclk_dir(plat);
> > > +   if (ret)
> > > +           return ret;
> > > +
> > > +   regmap_write(dwmac->apb_regmap, GMAC_RXCLK_DELAY_CTRL,
> > > +                GMAC_RXCLK_DELAY_VAL(dwmac->rx_delay));
> > > +   regmap_write(dwmac->apb_regmap, GMAC_TXCLK_DELAY_CTRL,
> > > +                GMAC_TXCLK_DELAY_VAL(dwmac->tx_delay));
> > > +
> > > +   thead_dwmac_fix_speed(dwmac, SPEED_1000, 0);
> > > +
> > > +   return thead_dwmac_enable_clk(plat);
> > > +}
> > > +
> > > +static int thead_dwmac_probe(struct platform_device *pdev)
> > > +{
> > > +   struct plat_stmmacenet_data *plat;
> > > +   struct stmmac_resources stmmac_res;
> > > +   struct thead_dwmac *dwmac;
> > > +   struct device_node *np = pdev->dev.of_node;
> > > +   u32 delay_ps;
> > > +   int ret;
> > > +
> > > +   ret = stmmac_get_platform_resources(pdev, &stmmac_res);
> > > +   if (ret)
> > > +           return dev_err_probe(&pdev->dev, ret,
> > > +                                "failed to get resources\n");
> > > +
> >
> > > +   plat = stmmac_probe_config_dt(pdev, stmmac_res.mac);
> >
> > This can be replaced with devm_stmmac_probe_config_dt() so the
> > stmmac_remove_config_dt() invocation would be dropped.
> >
> > > +   if (IS_ERR(plat))
> > > +           return dev_err_probe(&pdev->dev, PTR_ERR(plat),
> > > +                                "dt configuration failed\n");
> > > +
> > > +   dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
> > > +   if (!dwmac) {
> > > +           ret = -ENOMEM;
> > > +           goto err_remove_config_dt;
> > > +   }
> > > +
> > > +   if (!of_property_read_u32(np, "rx-internal-delay-ps", &delay_ps))
> > > +           dwmac->rx_delay = delay_ps;
> > > +   if (!of_property_read_u32(np, "tx-internal-delay-ps", &delay_ps))
> > > +           dwmac->tx_delay = delay_ps;
> > > +
> > > +   dwmac->apb_regmap = syscon_regmap_lookup_by_phandle(np, "thead,gmacapb");
> > > +   if (IS_ERR(dwmac->apb_regmap)) {
> > > +           ret = dev_err_probe(&pdev->dev, PTR_ERR(dwmac->apb_regmap),
> > > +                               "Failed to get gmac apb syscon\n");
> > > +           goto err_remove_config_dt;
> > > +   }
> > > +
> > > +   dwmac->dev = &pdev->dev;
> > > +   dwmac->plat = plat;
> > > +   plat->bsp_priv = dwmac;
> > > +   plat->fix_mac_speed = thead_dwmac_fix_speed;
> > > +
> >
> > > +   ret = thead_dwmac_init(pdev, plat);
> > > +   if (ret)
> > > +           goto err_remove_config_dt;
> > > +
> > > +   ret = stmmac_dvr_probe(&pdev->dev, plat, &stmmac_res);
> >
> > This can be replaced with:
> > plat->init = thead_dwmac_init;
> > ret = devm_stmmac_pltfr_probe();
> >
> > > +   if (ret)
> > > +           goto err_remove_config_dt;
> > > +
> > > +   return 0;
> > > +
> >
> > > +err_remove_config_dt:
> > > +   stmmac_remove_config_dt(pdev, plat);
> > > +
> > > +   return ret;
> >
> > This can be dropped if devm_stmmac_probe_config_dt() is utilized.
> >
> > > +}
> > > +
> > > +static const struct of_device_id thead_dwmac_match[] = {
> >
> > > +   { .compatible = "thead,th1520-dwmac" },
> >
> > See my comment to the bindings about the compatible string suffix.
> >
> > > +   { }
> > > +};
> > > +MODULE_DEVICE_TABLE(of, thead_dwmac_match);
> > > +
> > > +static struct platform_driver thead_dwmac_driver = {
> > > +   .probe = thead_dwmac_probe,
> >
> > > +   .remove_new = stmmac_pltfr_remove,
> >
> > This can be dropped if devm_stmmac_probe_config_dt() and
> > devm_stmmac_pltfr_probe() are utilized.
> >
> > > +   .driver = {
> > > +           .name = "thead-dwmac",
> > > +           .pm = &stmmac_pltfr_pm_ops,
> > > +           .of_match_table = thead_dwmac_match,
> > > +   },
> > > +};
> > > +module_platform_driver(thead_dwmac_driver);
> > > +
> > > +MODULE_AUTHOR("T-HEAD");
> > > +MODULE_AUTHOR("Jisheng Zhang <jszhang@kernel.org>");
> >
> > > +MODULE_DESCRIPTION("T-HEAD dwmac platform driver");
> >                               ^
> >                               |
> > Capitalize? ------------------+
> >
> > -Serge(y)
> >
> > > +MODULE_LICENSE("GPL");
> > > --
> > > 2.40.1
> > >
> > >
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

On Mon, Aug 28, 2023 at 11:41:47PM +0800, Jisheng Zhang wrote:
> On Mon, Aug 28, 2023 at 04:40:19PM +0300, Serge Semin wrote:
> > On Sun, Aug 27, 2023 at 05:17:10PM +0800, Jisheng Zhang wrote:
> > > Add dwmac glue driver to support the dwmac on the T-HEAD TH1520 SoC.
> > > 
> > > Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> > > ---
> > >  drivers/net/ethernet/stmicro/stmmac/Kconfig   |  11 +
> > >  drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
> > >  .../net/ethernet/stmicro/stmmac/dwmac-thead.c | 302 ++++++++++++++++++
> > >  3 files changed, 314 insertions(+)
> > >  create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > > 
> > > diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > index 06c6871f8788..1bf71804c270 100644
> > > --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > @@ -216,6 +216,17 @@ config DWMAC_SUN8I
> > >  	  stmmac device driver. This driver is used for H3/A83T/A64
> > >  	  EMAC ethernet controller.
> > >  
> > > +config DWMAC_THEAD
> > > +	tristate "T-HEAD dwmac support"
> > > +	depends on OF && (ARCH_THEAD || COMPILE_TEST)
> > > +	select MFD_SYSCON
> > > +	help
> > > +	  Support for ethernet controllers on T-HEAD RISC-V SoCs
> > > +
> > > +	  This selects the T-HEAD platform specific glue layer support for
> > > +	  the stmmac device driver. This driver is used for T-HEAD TH1520
> > > +	  ethernet controller.
> > > +
> > >  config DWMAC_IMX8
> > >  	tristate "NXP IMX8 DWMAC support"
> > >  	default ARCH_MXC
> > > diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > index 5b57aee19267..d73171ed6ad7 100644
> > > --- a/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > +++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > @@ -27,6 +27,7 @@ obj-$(CONFIG_DWMAC_STI)		+= dwmac-sti.o
> > >  obj-$(CONFIG_DWMAC_STM32)	+= dwmac-stm32.o
> > >  obj-$(CONFIG_DWMAC_SUNXI)	+= dwmac-sunxi.o
> > >  obj-$(CONFIG_DWMAC_SUN8I)	+= dwmac-sun8i.o
> > > +obj-$(CONFIG_DWMAC_THEAD)	+= dwmac-thead.o
> > >  obj-$(CONFIG_DWMAC_DWC_QOS_ETH)	+= dwmac-dwc-qos-eth.o
> > >  obj-$(CONFIG_DWMAC_INTEL_PLAT)	+= dwmac-intel-plat.o
> > >  obj-$(CONFIG_DWMAC_GENERIC)	+= dwmac-generic.o
> > > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > > new file mode 100644
> > > index 000000000000..85135ef05906
> > > --- /dev/null
> > > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > > @@ -0,0 +1,302 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * T-HEAD DWMAC platform driver
> > > + *
> > > + * Copyright (C) 2021 Alibaba Group Holding Limited.
> > > + * Copyright (C) 2023 Jisheng Zhang <jszhang@kernel.org>
> > > + *
> > > + */
> > > +
> > > +#include <linux/bitfield.h>
> > > +#include <linux/mfd/syscon.h>
> > > +#include <linux/module.h>
> > > +#include <linux/of.h>
> > > +#include <linux/of_device.h>
> > > +#include <linux/of_net.h>
> > > +#include <linux/platform_device.h>
> > > +#include <linux/regmap.h>
> > > +
> > > +#include "stmmac_platform.h"
> > > +
> > > +#define GMAC_CLK_EN			0x00
> > > +#define  GMAC_TX_CLK_EN			BIT(1)
> > > +#define  GMAC_TX_CLK_N_EN		BIT(2)
> > > +#define  GMAC_TX_CLK_OUT_EN		BIT(3)
> > > +#define  GMAC_RX_CLK_EN			BIT(4)
> > > +#define  GMAC_RX_CLK_N_EN		BIT(5)
> > > +#define  GMAC_EPHY_REF_CLK_EN		BIT(6)
> > > +#define GMAC_RXCLK_DELAY_CTRL		0x04
> > > +#define  GMAC_RXCLK_BYPASS		BIT(15)
> > > +#define  GMAC_RXCLK_INVERT		BIT(14)
> > > +#define  GMAC_RXCLK_DELAY_MASK		GENMASK(4, 0)
> > > +#define  GMAC_RXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > > +#define GMAC_TXCLK_DELAY_CTRL		0x08
> > > +#define  GMAC_TXCLK_BYPASS		BIT(15)
> > > +#define  GMAC_TXCLK_INVERT		BIT(14)
> > > +#define  GMAC_TXCLK_DELAY_MASK		GENMASK(4, 0)
> > > +#define  GMAC_TXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > > +#define GMAC_PLLCLK_DIV			0x0c
> > > +#define  GMAC_PLLCLK_DIV_EN		BIT(31)
> > > +#define  GMAC_PLLCLK_DIV_MASK		GENMASK(7, 0)
> > > +#define  GMAC_PLLCLK_DIV_NUM(x)		FIELD_PREP(GMAC_PLLCLK_DIV_MASK, (x))
> > > +#define GMAC_GTXCLK_SEL			0x18
> > > +#define  GMAC_GTXCLK_SEL_PLL		BIT(0)
> > > +#define GMAC_INTF_CTRL			0x1c
> > > +#define  PHY_INTF_MASK			BIT(0)
> > > +#define  PHY_INTF_RGMII			FIELD_PREP(PHY_INTF_MASK, 1)
> > > +#define  PHY_INTF_MII_GMII		FIELD_PREP(PHY_INTF_MASK, 0)
> > > +#define GMAC_TXCLK_OEN			0x20
> > > +#define  TXCLK_DIR_MASK			BIT(0)
> > > +#define  TXCLK_DIR_OUTPUT		FIELD_PREP(TXCLK_DIR_MASK, 0)
> > > +#define  TXCLK_DIR_INPUT		FIELD_PREP(TXCLK_DIR_MASK, 1)
> > > +
> > > +#define GMAC_GMII_RGMII_RATE	125000000
> > > +#define GMAC_MII_RATE		25000000
> > > +
> > > +struct thead_dwmac {
> > > +	struct plat_stmmacenet_data *plat;
> > > +	struct regmap *apb_regmap;
> > > +	struct device *dev;
> > > +	u32 rx_delay;
> > > +	u32 tx_delay;
> > > +};
> > > +
> > > +static int thead_dwmac_set_phy_if(struct plat_stmmacenet_data *plat)
> > > +{
> > > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > > +	u32 phyif;
> > > +
> > > +	switch (plat->interface) {
> > > +	case PHY_INTERFACE_MODE_MII:
> > > +		phyif = PHY_INTF_MII_GMII;
> > > +		break;
> > > +	case PHY_INTERFACE_MODE_RGMII:
> > > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > > +		phyif = PHY_INTF_RGMII;
> > > +		break;
> > > +	default:
> > > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > +			plat->interface);
> > > +		return -EINVAL;
> > > +	};
> > > +
> > > +	regmap_write(dwmac->apb_regmap, GMAC_INTF_CTRL, phyif);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int thead_dwmac_set_txclk_dir(struct plat_stmmacenet_data *plat)
> > > +{
> > > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > > +	u32 txclk_dir;
> > > +
> > > +	switch (plat->interface) {
> > > +	case PHY_INTERFACE_MODE_MII:
> > > +		txclk_dir = TXCLK_DIR_INPUT;
> > > +		break;
> > > +	case PHY_INTERFACE_MODE_RGMII:
> > > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > > +		txclk_dir = TXCLK_DIR_OUTPUT;
> > > +		break;
> > > +	default:
> > > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > +			plat->interface);
> > > +		return -EINVAL;
> > > +	};
> > > +
> > > +	regmap_write(dwmac->apb_regmap, GMAC_TXCLK_OEN, txclk_dir);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static void thead_dwmac_fix_speed(void *priv, unsigned int speed, unsigned int mode)
> > > +{
> > > +	struct thead_dwmac *dwmac = priv;
> > > +	struct plat_stmmacenet_data *plat = dwmac->plat;
> > > +	unsigned long rate;
> > > +	u32 div;
> > > +
> > > +	switch (plat->interface) {
> > > +	/* For MII, rxc/txc is provided by phy */
> > > +	case PHY_INTERFACE_MODE_MII:
> > > +		return;
> > > +
> > > +	case PHY_INTERFACE_MODE_RGMII:
> > > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > 
> > > +		rate = clk_get_rate(plat->stmmac_clk);
> > > +		if (!rate || rate % GMAC_GMII_RGMII_RATE != 0 ||
> > > +		    rate % GMAC_MII_RATE != 0) {
> > > +			dev_err(dwmac->dev, "invalid gmac rate %ld\n", rate);
> > > +			return;
> > > +		}
> > > +
> > > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV, GMAC_PLLCLK_DIV_EN, 0);
> > > +
> > > +		switch (speed) {
> > > +		case SPEED_1000:
> > > +			div = rate / GMAC_GMII_RGMII_RATE;
> > > +			break;
> > > +		case SPEED_100:
> > > +			div = rate / GMAC_MII_RATE;
> > > +			break;
> > > +		case SPEED_10:
> > > +			div = rate * 10 / GMAC_MII_RATE;
> > > +			break;
> > > +		default:
> > > +			dev_err(dwmac->dev, "invalid speed %u\n", speed);
> > > +			return;
> > > +		}
> > > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > > +				   GMAC_PLLCLK_DIV_MASK, GMAC_PLLCLK_DIV_NUM(div));
> > > +
> > > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > > +				   GMAC_PLLCLK_DIV_EN, GMAC_PLLCLK_DIV_EN);
> > 
> > This chunk looks like a hard-coded implementation of the
> > CLK_SET_RATE_GATE Tx-clocks rate setup which parental clock is the
> > "stmmaceth" clock. I suggest to move it to the respective driver, add
> > a "tx" clock to the bindings and use the common clock kernel API
> > methods here only.
> 
> I did consider your solution before writing the code, here are the
> reasons why I dropped it:
> 

> There's no any clk IP here, the HW just puts several
> gmac related control bits here, such as rx/tx delay, bypass, invert
> interface choice, clk direction. 

You omitted the essential part of your code which I pointed out.

> From this point of view, it looks more
> like a syscon rather than clk.

Toggling control bits is surely the syscon work. But gating a parental
clock, settings up the parental clock _divider_ and ungating the clock
back is the clock controller function. So it means your syscon is just
a normal multi-function device, which one of the function is the clock
controller.

It's not like your situation is unique. For instance in case of a SoC
I was working with recently Clock Control Unit (CCU) was actually a
multi-function device which had:
1. PLLs and Dividers supplying the clocks to the SoC components.
2. SoC components reset controller.
3. I2C-interface controller.
4. AXI-bus errors report registers.
5. PCIe-controller tunings (LTSSM, link up/down, etc)
6. SATA-controller tunings.
7. Full SoC reset controller (syscon reboot),
8. L2-cache tunings controller.
with the sub-functions CSRs joint in a single space. In that case the
PCIe-controller tunings and a lot of its reference clocks settings
were intermixed in a single chunk of the registers. So I had to create
a driver for the clocks anyway including all the PCIe reference
clock and refer to the syscon in the PCIe-controller device node for
the respective PCIe platform-specific tunings.

> 
> Secondly, I see other SoCs did similar for this case, such as
> dwmac-visconti, dwmac-meson8b, dwmac-ipq806x, dwmac-socfpga and so on.
> They met similar issue as the above.

First I failed to find any clock-related things in the dwmac-socfpga
driver looking in anyway as yours. Second the dwmac-meson8b driver
creates a generic clock handler right in the driver. I don't think
it's a great solution but at the very least it registers the clock
handler in the kernel. But seeing the PROG_ETHERNET CSR is of 8 bytes
long there (0xc8834540 0x8) and defined at looking random base address
it's definitely a part of a Meson system controller which just
directly passed to the device driver. It's not correct. That part
should have been at least specified as a syscon too. Third the
dwmac-visconti driver is not a good example seeing it defines some
specific registers way away from the NIC CSR space. It's most likely a
separate device like syscon. Fourth dwmac-ipq806x driver
implementation looks indeed like yours.

In anyway I don't say your solution is fully wrong. At the very least
you have a syscon node defined. But it just makes you adding
incomplete device/platform bindings. Your network device do have the
Tx reference clock as a part of the separate system controller, but
you have to omit it because of the syscon property. You do have a
syscon node, but don't have its clock function exported. So AFAICS in
your case things can be implemented in a more canonical way than they
are now.

-Serge(y)

> 
> PS: here is the initial th1520 clk driver, as is seen, the clk IP is
> different from the control logic here.
> 
> https://lore.kernel.org/linux-riscv/20230515054402.27633-1-frank.li@vivo.com/
> 
> Thanks
> 
> > 
> > > +		break;
> > > +	default:
> > > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > +			plat->interface);
> > > +		return;
> > > +	}
> > > +}
> > > +
> > > +static int thead_dwmac_enable_clk(struct plat_stmmacenet_data *plat)
> > > +{
> > > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > > +	u32 reg;
> > > +
> > > +	switch (plat->interface) {
> > > +	case PHY_INTERFACE_MODE_MII:
> > > +		reg = GMAC_RX_CLK_EN | GMAC_TX_CLK_EN;
> > > +		break;
> > > +
> > > +	case PHY_INTERFACE_MODE_RGMII:
> > > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > > +		/* use pll */
> > > +		regmap_write(dwmac->apb_regmap, GMAC_GTXCLK_SEL, GMAC_GTXCLK_SEL_PLL);
> > > +
> > 
> > > +		reg = GMAC_TX_CLK_EN | GMAC_TX_CLK_N_EN | GMAC_TX_CLK_OUT_EN |
> > > +		      GMAC_RX_CLK_EN | GMAC_RX_CLK_N_EN;
> > 
> > Similarly settings these flags looks like just clock gates which can
> > also be moved to the clock driver.
> > 
> > > +		break;
> > > +
> > > +	default:
> > > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > +			plat->interface);
> > > +		return -EINVAL;
> > > +	}
> > > +
> > > +	regmap_write(dwmac->apb_regmap, GMAC_CLK_EN, reg);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int thead_dwmac_init(struct platform_device *pdev,
> > > +			    struct plat_stmmacenet_data *plat)
> > > +{
> > > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > > +	int ret;
> > > +
> > > +	ret = thead_dwmac_set_phy_if(plat);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	ret = thead_dwmac_set_txclk_dir(plat);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	regmap_write(dwmac->apb_regmap, GMAC_RXCLK_DELAY_CTRL,
> > > +		     GMAC_RXCLK_DELAY_VAL(dwmac->rx_delay));
> > > +	regmap_write(dwmac->apb_regmap, GMAC_TXCLK_DELAY_CTRL,
> > > +		     GMAC_TXCLK_DELAY_VAL(dwmac->tx_delay));
> > > +
> > > +	thead_dwmac_fix_speed(dwmac, SPEED_1000, 0);
> > > +
> > > +	return thead_dwmac_enable_clk(plat);
> > > +}
> > > +
> > > +static int thead_dwmac_probe(struct platform_device *pdev)
> > > +{
> > > +	struct plat_stmmacenet_data *plat;
> > > +	struct stmmac_resources stmmac_res;
> > > +	struct thead_dwmac *dwmac;
> > > +	struct device_node *np = pdev->dev.of_node;
> > > +	u32 delay_ps;
> > > +	int ret;
> > > +
> > > +	ret = stmmac_get_platform_resources(pdev, &stmmac_res);
> > > +	if (ret)
> > > +		return dev_err_probe(&pdev->dev, ret,
> > > +				     "failed to get resources\n");
> > > +
> > 
> > > +	plat = stmmac_probe_config_dt(pdev, stmmac_res.mac);
> > 
> > This can be replaced with devm_stmmac_probe_config_dt() so the
> > stmmac_remove_config_dt() invocation would be dropped.
> > 
> > > +	if (IS_ERR(plat))
> > > +		return dev_err_probe(&pdev->dev, PTR_ERR(plat),
> > > +				     "dt configuration failed\n");
> > > +
> > > +	dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
> > > +	if (!dwmac) {
> > > +		ret = -ENOMEM;
> > > +		goto err_remove_config_dt;
> > > +	}
> > > +
> > > +	if (!of_property_read_u32(np, "rx-internal-delay-ps", &delay_ps))
> > > +		dwmac->rx_delay = delay_ps;
> > > +	if (!of_property_read_u32(np, "tx-internal-delay-ps", &delay_ps))
> > > +		dwmac->tx_delay = delay_ps;
> > > +
> > > +	dwmac->apb_regmap = syscon_regmap_lookup_by_phandle(np, "thead,gmacapb");
> > > +	if (IS_ERR(dwmac->apb_regmap)) {
> > > +		ret = dev_err_probe(&pdev->dev, PTR_ERR(dwmac->apb_regmap),
> > > +				    "Failed to get gmac apb syscon\n");
> > > +		goto err_remove_config_dt;
> > > +	}
> > > +
> > > +	dwmac->dev = &pdev->dev;
> > > +	dwmac->plat = plat;
> > > +	plat->bsp_priv = dwmac;
> > > +	plat->fix_mac_speed = thead_dwmac_fix_speed;
> > > +
> > 
> > > +	ret = thead_dwmac_init(pdev, plat);
> > > +	if (ret)
> > > +		goto err_remove_config_dt;
> > > +
> > > +	ret = stmmac_dvr_probe(&pdev->dev, plat, &stmmac_res);
> > 
> > This can be replaced with:
> > plat->init = thead_dwmac_init;
> > ret = devm_stmmac_pltfr_probe();
> > 
> > > +	if (ret)
> > > +		goto err_remove_config_dt;
> > > +
> > > +	return 0;
> > > +
> > 
> > > +err_remove_config_dt:
> > > +	stmmac_remove_config_dt(pdev, plat);
> > > +
> > > +	return ret;
> > 
> > This can be dropped if devm_stmmac_probe_config_dt() is utilized.
> > 
> > > +}
> > > +
> > > +static const struct of_device_id thead_dwmac_match[] = {
> > 
> > > +	{ .compatible = "thead,th1520-dwmac" },
> > 
> > See my comment to the bindings about the compatible string suffix.
> > 
> > > +	{ }
> > > +};
> > > +MODULE_DEVICE_TABLE(of, thead_dwmac_match);
> > > +
> > > +static struct platform_driver thead_dwmac_driver = {
> > > +	.probe = thead_dwmac_probe,
> > 
> > > +	.remove_new = stmmac_pltfr_remove,
> > 
> > This can be dropped if devm_stmmac_probe_config_dt() and
> > devm_stmmac_pltfr_probe() are utilized.
> > 
> > > +	.driver = {
> > > +		.name = "thead-dwmac",
> > > +		.pm = &stmmac_pltfr_pm_ops,
> > > +		.of_match_table = thead_dwmac_match,
> > > +	},
> > > +};
> > > +module_platform_driver(thead_dwmac_driver);
> > > +
> > > +MODULE_AUTHOR("T-HEAD");
> > > +MODULE_AUTHOR("Jisheng Zhang <jszhang@kernel.org>");
> > 
> > > +MODULE_DESCRIPTION("T-HEAD dwmac platform driver");
> >                               ^
> >                               |
> > Capitalize? ------------------+
> > 
> > -Serge(y)
> > 
> > > +MODULE_LICENSE("GPL");
> > > -- 
> > > 2.40.1
> > > 
> > >

On Tue, Aug 29, 2023 at 12:13:58AM +0800, Jisheng Zhang wrote:
> On Mon, Aug 28, 2023 at 06:58:11PM +0300, Serge Semin wrote:
> > On Sun, Aug 27, 2023 at 05:17:10PM +0800, Jisheng Zhang wrote:
> > > Add dwmac glue driver to support the dwmac on the T-HEAD TH1520 SoC.
> > > 
> > > Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> > > ---
> > >  drivers/net/ethernet/stmicro/stmmac/Kconfig   |  11 +
> > >  drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
> > >  .../net/ethernet/stmicro/stmmac/dwmac-thead.c | 302 ++++++++++++++++++
> > >  3 files changed, 314 insertions(+)
> > >  create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > > 
> > > diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > index 06c6871f8788..1bf71804c270 100644
> > > --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > @@ -216,6 +216,17 @@ config DWMAC_SUN8I
> > >  	  stmmac device driver. This driver is used for H3/A83T/A64
> > >  	  EMAC ethernet controller.
> > >  
> > > +config DWMAC_THEAD
> > > +	tristate "T-HEAD dwmac support"
> > > +	depends on OF && (ARCH_THEAD || COMPILE_TEST)
> > > +	select MFD_SYSCON
> > > +	help
> > > +	  Support for ethernet controllers on T-HEAD RISC-V SoCs
> > > +
> > > +	  This selects the T-HEAD platform specific glue layer support for
> > > +	  the stmmac device driver. This driver is used for T-HEAD TH1520
> > > +	  ethernet controller.
> > > +
> > >  config DWMAC_IMX8
> > >  	tristate "NXP IMX8 DWMAC support"
> > >  	default ARCH_MXC
> > > diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > index 5b57aee19267..d73171ed6ad7 100644
> > > --- a/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > +++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > @@ -27,6 +27,7 @@ obj-$(CONFIG_DWMAC_STI)		+= dwmac-sti.o
> > >  obj-$(CONFIG_DWMAC_STM32)	+= dwmac-stm32.o
> > >  obj-$(CONFIG_DWMAC_SUNXI)	+= dwmac-sunxi.o
> > >  obj-$(CONFIG_DWMAC_SUN8I)	+= dwmac-sun8i.o
> > > +obj-$(CONFIG_DWMAC_THEAD)	+= dwmac-thead.o
> > >  obj-$(CONFIG_DWMAC_DWC_QOS_ETH)	+= dwmac-dwc-qos-eth.o
> > >  obj-$(CONFIG_DWMAC_INTEL_PLAT)	+= dwmac-intel-plat.o
> > >  obj-$(CONFIG_DWMAC_GENERIC)	+= dwmac-generic.o
> > > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > > new file mode 100644
> > > index 000000000000..85135ef05906
> > > --- /dev/null
> > > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > > @@ -0,0 +1,302 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * T-HEAD DWMAC platform driver
> > > + *
> > > + * Copyright (C) 2021 Alibaba Group Holding Limited.
> > > + * Copyright (C) 2023 Jisheng Zhang <jszhang@kernel.org>
> > > + *
> > > + */
> > > +
> > > +#include <linux/bitfield.h>
> > > +#include <linux/mfd/syscon.h>
> > > +#include <linux/module.h>
> > > +#include <linux/of.h>
> > > +#include <linux/of_device.h>
> > > +#include <linux/of_net.h>
> > > +#include <linux/platform_device.h>
> > > +#include <linux/regmap.h>
> > > +
> > > +#include "stmmac_platform.h"
> > > +
> > > +#define GMAC_CLK_EN			0x00
> > > +#define  GMAC_TX_CLK_EN			BIT(1)
> > > +#define  GMAC_TX_CLK_N_EN		BIT(2)
> > > +#define  GMAC_TX_CLK_OUT_EN		BIT(3)
> > > +#define  GMAC_RX_CLK_EN			BIT(4)
> > > +#define  GMAC_RX_CLK_N_EN		BIT(5)
> > > +#define  GMAC_EPHY_REF_CLK_EN		BIT(6)
> > > +#define GMAC_RXCLK_DELAY_CTRL		0x04
> > > +#define  GMAC_RXCLK_BYPASS		BIT(15)
> > > +#define  GMAC_RXCLK_INVERT		BIT(14)
> > > +#define  GMAC_RXCLK_DELAY_MASK		GENMASK(4, 0)
> > > +#define  GMAC_RXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > > +#define GMAC_TXCLK_DELAY_CTRL		0x08
> > > +#define  GMAC_TXCLK_BYPASS		BIT(15)
> > > +#define  GMAC_TXCLK_INVERT		BIT(14)
> > > +#define  GMAC_TXCLK_DELAY_MASK		GENMASK(4, 0)
> > > +#define  GMAC_TXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > > +#define GMAC_PLLCLK_DIV			0x0c
> > > +#define  GMAC_PLLCLK_DIV_EN		BIT(31)
> > > +#define  GMAC_PLLCLK_DIV_MASK		GENMASK(7, 0)
> > > +#define  GMAC_PLLCLK_DIV_NUM(x)		FIELD_PREP(GMAC_PLLCLK_DIV_MASK, (x))
> > > +#define GMAC_GTXCLK_SEL			0x18
> > > +#define  GMAC_GTXCLK_SEL_PLL		BIT(0)
> > > +#define GMAC_INTF_CTRL			0x1c
> > > +#define  PHY_INTF_MASK			BIT(0)
> > > +#define  PHY_INTF_RGMII			FIELD_PREP(PHY_INTF_MASK, 1)
> > > +#define  PHY_INTF_MII_GMII		FIELD_PREP(PHY_INTF_MASK, 0)
> > > +#define GMAC_TXCLK_OEN			0x20
> > > +#define  TXCLK_DIR_MASK			BIT(0)
> > > +#define  TXCLK_DIR_OUTPUT		FIELD_PREP(TXCLK_DIR_MASK, 0)
> > > +#define  TXCLK_DIR_INPUT		FIELD_PREP(TXCLK_DIR_MASK, 1)
> > > +
> > > +#define GMAC_GMII_RGMII_RATE	125000000
> > > +#define GMAC_MII_RATE		25000000
> > > +
> > > +struct thead_dwmac {
> > > +	struct plat_stmmacenet_data *plat;
> > > +	struct regmap *apb_regmap;
> > > +	struct device *dev;
> > > +	u32 rx_delay;
> > > +	u32 tx_delay;
> > > +};
> > > +
> > > +static int thead_dwmac_set_phy_if(struct plat_stmmacenet_data *plat)
> > > +{
> > > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > > +	u32 phyif;
> > > +
> > > +	switch (plat->interface) {
> > > +	case PHY_INTERFACE_MODE_MII:
> > > +		phyif = PHY_INTF_MII_GMII;
> > > +		break;
> > > +	case PHY_INTERFACE_MODE_RGMII:
> > > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > > +		phyif = PHY_INTF_RGMII;
> > > +		break;
> > > +	default:
> > > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > +			plat->interface);
> > > +		return -EINVAL;
> > > +	};
> > > +
> > > +	regmap_write(dwmac->apb_regmap, GMAC_INTF_CTRL, phyif);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int thead_dwmac_set_txclk_dir(struct plat_stmmacenet_data *plat)
> > > +{
> > > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > > +	u32 txclk_dir;
> > > +
> > > +	switch (plat->interface) {
> > > +	case PHY_INTERFACE_MODE_MII:
> > > +		txclk_dir = TXCLK_DIR_INPUT;
> > > +		break;
> > > +	case PHY_INTERFACE_MODE_RGMII:
> > > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > > +		txclk_dir = TXCLK_DIR_OUTPUT;
> > > +		break;
> > > +	default:
> > > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > +			plat->interface);
> > > +		return -EINVAL;
> > > +	};
> > > +
> > > +	regmap_write(dwmac->apb_regmap, GMAC_TXCLK_OEN, txclk_dir);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static void thead_dwmac_fix_speed(void *priv, unsigned int speed, unsigned int mode)
> > > +{
> > > +	struct thead_dwmac *dwmac = priv;
> > > +	struct plat_stmmacenet_data *plat = dwmac->plat;
> > > +	unsigned long rate;
> > > +	u32 div;
> > > +
> > > +	switch (plat->interface) {
> > > +	/* For MII, rxc/txc is provided by phy */
> > > +	case PHY_INTERFACE_MODE_MII:
> > > +		return;
> > > +
> > > +	case PHY_INTERFACE_MODE_RGMII:
> > > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > > +		rate = clk_get_rate(plat->stmmac_clk);
> > > +		if (!rate || rate % GMAC_GMII_RGMII_RATE != 0 ||
> > > +		    rate % GMAC_MII_RATE != 0) {
> > > +			dev_err(dwmac->dev, "invalid gmac rate %ld\n", rate);
> > > +			return;
> > > +		}
> > > +
> > > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV, GMAC_PLLCLK_DIV_EN, 0);
> > > +
> > > +		switch (speed) {
> > > +		case SPEED_1000:
> > > +			div = rate / GMAC_GMII_RGMII_RATE;
> > > +			break;
> > > +		case SPEED_100:
> > > +			div = rate / GMAC_MII_RATE;
> > > +			break;
> > > +		case SPEED_10:
> > > +			div = rate * 10 / GMAC_MII_RATE;
> > > +			break;
> > > +		default:
> > > +			dev_err(dwmac->dev, "invalid speed %u\n", speed);
> > > +			return;
> > > +		}
> > > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > > +				   GMAC_PLLCLK_DIV_MASK, GMAC_PLLCLK_DIV_NUM(div));
> > > +
> > > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > > +				   GMAC_PLLCLK_DIV_EN, GMAC_PLLCLK_DIV_EN);
> > > +		break;
> > > +	default:
> > > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > +			plat->interface);
> > > +		return;
> > > +	}
> > > +}
> > > +
> > > +static int thead_dwmac_enable_clk(struct plat_stmmacenet_data *plat)
> > > +{
> > > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > > +	u32 reg;
> > > +
> > > +	switch (plat->interface) {
> > > +	case PHY_INTERFACE_MODE_MII:
> > > +		reg = GMAC_RX_CLK_EN | GMAC_TX_CLK_EN;
> > > +		break;
> > > +
> > > +	case PHY_INTERFACE_MODE_RGMII:
> > > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > > +		/* use pll */
> > > +		regmap_write(dwmac->apb_regmap, GMAC_GTXCLK_SEL, GMAC_GTXCLK_SEL_PLL);
> > > +
> > > +		reg = GMAC_TX_CLK_EN | GMAC_TX_CLK_N_EN | GMAC_TX_CLK_OUT_EN |
> > > +		      GMAC_RX_CLK_EN | GMAC_RX_CLK_N_EN;
> > > +		break;
> > > +
> > > +	default:
> > > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > +			plat->interface);
> > > +		return -EINVAL;
> > > +	}
> > > +
> > > +	regmap_write(dwmac->apb_regmap, GMAC_CLK_EN, reg);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int thead_dwmac_init(struct platform_device *pdev,
> > > +			    struct plat_stmmacenet_data *plat)
> > > +{
> > > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > > +	int ret;
> > > +
> > > +	ret = thead_dwmac_set_phy_if(plat);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	ret = thead_dwmac_set_txclk_dir(plat);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > 
> > > +	regmap_write(dwmac->apb_regmap, GMAC_RXCLK_DELAY_CTRL,
> > > +		     GMAC_RXCLK_DELAY_VAL(dwmac->rx_delay));
> > > +	regmap_write(dwmac->apb_regmap, GMAC_TXCLK_DELAY_CTRL,
> > > +		     GMAC_TXCLK_DELAY_VAL(dwmac->tx_delay));
> > 
> > Just noticed. This doesn't look right because:
> > 1. Are you sure your hardware expects the delays being specified in
> > picoseconds. It's most likely a number of reference clock cycles and
> > thus the DT-properties values should be properly converted.
> 
> Good catch! I need to check further.
> > 2. Both delays should be added only for "rgmii" phy-mode, Tx clock
> > delay - for "rgmii-rxid" phy-mode, Rx clock delay - for "rgmii-txid"
> > phy-mode.
> 

> For MII, the rxc/txc is provided by phy, so setting those delays
> won't impact MII.

I am talking about _RGMII_ in this case which based on the
thead_dwmac_set_phy_if() method is supported by this controller.
rgmii{-(tx|rx)id} modes are provided so to prevent both MAC and PHY
adding the delays in the RGMII interface. Imagine you have a PHY with
the fixed delays meanwhile you have them also added in the MAC. You
may and likely will end up with the traffic loss then.

As a reference take a closer look at for instance rk_gmac_powerup()
method implemented in the dwmac-rk.c driver.

-Serge(y)

> > 
> > -Serge(y)
> > 
> > > +
> > > +	thead_dwmac_fix_speed(dwmac, SPEED_1000, 0);
> > > +
> > > +	return thead_dwmac_enable_clk(plat);
> > > +}
> > > +
> > > +static int thead_dwmac_probe(struct platform_device *pdev)
> > > +{
> > > +	struct plat_stmmacenet_data *plat;
> > > +	struct stmmac_resources stmmac_res;
> > > +	struct thead_dwmac *dwmac;
> > > +	struct device_node *np = pdev->dev.of_node;
> > > +	u32 delay_ps;
> > > +	int ret;
> > > +
> > > +	ret = stmmac_get_platform_resources(pdev, &stmmac_res);
> > > +	if (ret)
> > > +		return dev_err_probe(&pdev->dev, ret,
> > > +				     "failed to get resources\n");
> > > +
> > > +	plat = stmmac_probe_config_dt(pdev, stmmac_res.mac);
> > > +	if (IS_ERR(plat))
> > > +		return dev_err_probe(&pdev->dev, PTR_ERR(plat),
> > > +				     "dt configuration failed\n");
> > > +
> > > +	dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
> > > +	if (!dwmac) {
> > > +		ret = -ENOMEM;
> > > +		goto err_remove_config_dt;
> > > +	}
> > > +
> > > +	if (!of_property_read_u32(np, "rx-internal-delay-ps", &delay_ps))
> > > +		dwmac->rx_delay = delay_ps;
> > > +	if (!of_property_read_u32(np, "tx-internal-delay-ps", &delay_ps))
> > > +		dwmac->tx_delay = delay_ps;
> > > +
> > > +	dwmac->apb_regmap = syscon_regmap_lookup_by_phandle(np, "thead,gmacapb");
> > > +	if (IS_ERR(dwmac->apb_regmap)) {
> > > +		ret = dev_err_probe(&pdev->dev, PTR_ERR(dwmac->apb_regmap),
> > > +				    "Failed to get gmac apb syscon\n");
> > > +		goto err_remove_config_dt;
> > > +	}
> > > +
> > > +	dwmac->dev = &pdev->dev;
> > > +	dwmac->plat = plat;
> > > +	plat->bsp_priv = dwmac;
> > > +	plat->fix_mac_speed = thead_dwmac_fix_speed;
> > > +
> > > +	ret = thead_dwmac_init(pdev, plat);
> > > +	if (ret)
> > > +		goto err_remove_config_dt;
> > > +
> > > +	ret = stmmac_dvr_probe(&pdev->dev, plat, &stmmac_res);
> > > +	if (ret)
> > > +		goto err_remove_config_dt;
> > > +
> > > +	return 0;
> > > +
> > > +err_remove_config_dt:
> > > +	stmmac_remove_config_dt(pdev, plat);
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static const struct of_device_id thead_dwmac_match[] = {
> > > +	{ .compatible = "thead,th1520-dwmac" },
> > > +	{ }
> > > +};
> > > +MODULE_DEVICE_TABLE(of, thead_dwmac_match);
> > > +
> > > +static struct platform_driver thead_dwmac_driver = {
> > > +	.probe = thead_dwmac_probe,
> > > +	.remove_new = stmmac_pltfr_remove,
> > > +	.driver = {
> > > +		.name = "thead-dwmac",
> > > +		.pm = &stmmac_pltfr_pm_ops,
> > > +		.of_match_table = thead_dwmac_match,
> > > +	},
> > > +};
> > > +module_platform_driver(thead_dwmac_driver);
> > > +
> > > +MODULE_AUTHOR("T-HEAD");
> > > +MODULE_AUTHOR("Jisheng Zhang <jszhang@kernel.org>");
> > > +MODULE_DESCRIPTION("T-HEAD dwmac platform driver");
> > > +MODULE_LICENSE("GPL");
> > > -- 
> > > 2.40.1
> > > 
> > >

On Mon, Aug 28, 2023 at 08:30:50PM +0300, Serge Semin wrote:
> On Mon, Aug 28, 2023 at 11:41:47PM +0800, Jisheng Zhang wrote:
> > On Mon, Aug 28, 2023 at 04:40:19PM +0300, Serge Semin wrote:
> > > On Sun, Aug 27, 2023 at 05:17:10PM +0800, Jisheng Zhang wrote:
> > > > Add dwmac glue driver to support the dwmac on the T-HEAD TH1520 SoC.
> > > > 
> > > > Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> > > > ---
> > > >  drivers/net/ethernet/stmicro/stmmac/Kconfig   |  11 +
> > > >  drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
> > > >  .../net/ethernet/stmicro/stmmac/dwmac-thead.c | 302 ++++++++++++++++++
> > > >  3 files changed, 314 insertions(+)
> > > >  create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > > > 
> > > > diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > > index 06c6871f8788..1bf71804c270 100644
> > > > --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > > +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > > @@ -216,6 +216,17 @@ config DWMAC_SUN8I
> > > >  	  stmmac device driver. This driver is used for H3/A83T/A64
> > > >  	  EMAC ethernet controller.
> > > >  
> > > > +config DWMAC_THEAD
> > > > +	tristate "T-HEAD dwmac support"
> > > > +	depends on OF && (ARCH_THEAD || COMPILE_TEST)
> > > > +	select MFD_SYSCON
> > > > +	help
> > > > +	  Support for ethernet controllers on T-HEAD RISC-V SoCs
> > > > +
> > > > +	  This selects the T-HEAD platform specific glue layer support for
> > > > +	  the stmmac device driver. This driver is used for T-HEAD TH1520
> > > > +	  ethernet controller.
> > > > +
> > > >  config DWMAC_IMX8
> > > >  	tristate "NXP IMX8 DWMAC support"
> > > >  	default ARCH_MXC
> > > > diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > > index 5b57aee19267..d73171ed6ad7 100644
> > > > --- a/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > > +++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > > @@ -27,6 +27,7 @@ obj-$(CONFIG_DWMAC_STI)		+= dwmac-sti.o
> > > >  obj-$(CONFIG_DWMAC_STM32)	+= dwmac-stm32.o
> > > >  obj-$(CONFIG_DWMAC_SUNXI)	+= dwmac-sunxi.o
> > > >  obj-$(CONFIG_DWMAC_SUN8I)	+= dwmac-sun8i.o
> > > > +obj-$(CONFIG_DWMAC_THEAD)	+= dwmac-thead.o
> > > >  obj-$(CONFIG_DWMAC_DWC_QOS_ETH)	+= dwmac-dwc-qos-eth.o
> > > >  obj-$(CONFIG_DWMAC_INTEL_PLAT)	+= dwmac-intel-plat.o
> > > >  obj-$(CONFIG_DWMAC_GENERIC)	+= dwmac-generic.o
> > > > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > > > new file mode 100644
> > > > index 000000000000..85135ef05906
> > > > --- /dev/null
> > > > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > > > @@ -0,0 +1,302 @@
> > > > +// SPDX-License-Identifier: GPL-2.0
> > > > +/*
> > > > + * T-HEAD DWMAC platform driver
> > > > + *
> > > > + * Copyright (C) 2021 Alibaba Group Holding Limited.
> > > > + * Copyright (C) 2023 Jisheng Zhang <jszhang@kernel.org>
> > > > + *
> > > > + */
> > > > +
> > > > +#include <linux/bitfield.h>
> > > > +#include <linux/mfd/syscon.h>
> > > > +#include <linux/module.h>
> > > > +#include <linux/of.h>
> > > > +#include <linux/of_device.h>
> > > > +#include <linux/of_net.h>
> > > > +#include <linux/platform_device.h>
> > > > +#include <linux/regmap.h>
> > > > +
> > > > +#include "stmmac_platform.h"
> > > > +
> > > > +#define GMAC_CLK_EN			0x00
> > > > +#define  GMAC_TX_CLK_EN			BIT(1)
> > > > +#define  GMAC_TX_CLK_N_EN		BIT(2)
> > > > +#define  GMAC_TX_CLK_OUT_EN		BIT(3)
> > > > +#define  GMAC_RX_CLK_EN			BIT(4)
> > > > +#define  GMAC_RX_CLK_N_EN		BIT(5)
> > > > +#define  GMAC_EPHY_REF_CLK_EN		BIT(6)
> > > > +#define GMAC_RXCLK_DELAY_CTRL		0x04
> > > > +#define  GMAC_RXCLK_BYPASS		BIT(15)
> > > > +#define  GMAC_RXCLK_INVERT		BIT(14)
> > > > +#define  GMAC_RXCLK_DELAY_MASK		GENMASK(4, 0)
> > > > +#define  GMAC_RXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > > > +#define GMAC_TXCLK_DELAY_CTRL		0x08
> > > > +#define  GMAC_TXCLK_BYPASS		BIT(15)
> > > > +#define  GMAC_TXCLK_INVERT		BIT(14)
> > > > +#define  GMAC_TXCLK_DELAY_MASK		GENMASK(4, 0)
> > > > +#define  GMAC_TXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > > > +#define GMAC_PLLCLK_DIV			0x0c
> > > > +#define  GMAC_PLLCLK_DIV_EN		BIT(31)
> > > > +#define  GMAC_PLLCLK_DIV_MASK		GENMASK(7, 0)
> > > > +#define  GMAC_PLLCLK_DIV_NUM(x)		FIELD_PREP(GMAC_PLLCLK_DIV_MASK, (x))
> > > > +#define GMAC_GTXCLK_SEL			0x18
> > > > +#define  GMAC_GTXCLK_SEL_PLL		BIT(0)
> > > > +#define GMAC_INTF_CTRL			0x1c
> > > > +#define  PHY_INTF_MASK			BIT(0)
> > > > +#define  PHY_INTF_RGMII			FIELD_PREP(PHY_INTF_MASK, 1)
> > > > +#define  PHY_INTF_MII_GMII		FIELD_PREP(PHY_INTF_MASK, 0)
> > > > +#define GMAC_TXCLK_OEN			0x20
> > > > +#define  TXCLK_DIR_MASK			BIT(0)
> > > > +#define  TXCLK_DIR_OUTPUT		FIELD_PREP(TXCLK_DIR_MASK, 0)
> > > > +#define  TXCLK_DIR_INPUT		FIELD_PREP(TXCLK_DIR_MASK, 1)
> > > > +
> > > > +#define GMAC_GMII_RGMII_RATE	125000000
> > > > +#define GMAC_MII_RATE		25000000
> > > > +
> > > > +struct thead_dwmac {
> > > > +	struct plat_stmmacenet_data *plat;
> > > > +	struct regmap *apb_regmap;
> > > > +	struct device *dev;
> > > > +	u32 rx_delay;
> > > > +	u32 tx_delay;
> > > > +};
> > > > +
> > > > +static int thead_dwmac_set_phy_if(struct plat_stmmacenet_data *plat)
> > > > +{
> > > > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > > > +	u32 phyif;
> > > > +
> > > > +	switch (plat->interface) {
> > > > +	case PHY_INTERFACE_MODE_MII:
> > > > +		phyif = PHY_INTF_MII_GMII;
> > > > +		break;
> > > > +	case PHY_INTERFACE_MODE_RGMII:
> > > > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > > > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > > > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > > > +		phyif = PHY_INTF_RGMII;
> > > > +		break;
> > > > +	default:
> > > > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > > +			plat->interface);
> > > > +		return -EINVAL;
> > > > +	};
> > > > +
> > > > +	regmap_write(dwmac->apb_regmap, GMAC_INTF_CTRL, phyif);
> > > > +
> > > > +	return 0;
> > > > +}
> > > > +
> > > > +static int thead_dwmac_set_txclk_dir(struct plat_stmmacenet_data *plat)
> > > > +{
> > > > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > > > +	u32 txclk_dir;
> > > > +
> > > > +	switch (plat->interface) {
> > > > +	case PHY_INTERFACE_MODE_MII:
> > > > +		txclk_dir = TXCLK_DIR_INPUT;
> > > > +		break;
> > > > +	case PHY_INTERFACE_MODE_RGMII:
> > > > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > > > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > > > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > > > +		txclk_dir = TXCLK_DIR_OUTPUT;
> > > > +		break;
> > > > +	default:
> > > > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > > +			plat->interface);
> > > > +		return -EINVAL;
> > > > +	};
> > > > +
> > > > +	regmap_write(dwmac->apb_regmap, GMAC_TXCLK_OEN, txclk_dir);
> > > > +
> > > > +	return 0;
> > > > +}
> > > > +
> > > > +static void thead_dwmac_fix_speed(void *priv, unsigned int speed, unsigned int mode)
> > > > +{
> > > > +	struct thead_dwmac *dwmac = priv;
> > > > +	struct plat_stmmacenet_data *plat = dwmac->plat;
> > > > +	unsigned long rate;
> > > > +	u32 div;
> > > > +
> > > > +	switch (plat->interface) {
> > > > +	/* For MII, rxc/txc is provided by phy */
> > > > +	case PHY_INTERFACE_MODE_MII:
> > > > +		return;
> > > > +
> > > > +	case PHY_INTERFACE_MODE_RGMII:
> > > > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > > > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > > > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > > 
> > > > +		rate = clk_get_rate(plat->stmmac_clk);
> > > > +		if (!rate || rate % GMAC_GMII_RGMII_RATE != 0 ||
> > > > +		    rate % GMAC_MII_RATE != 0) {
> > > > +			dev_err(dwmac->dev, "invalid gmac rate %ld\n", rate);
> > > > +			return;
> > > > +		}
> > > > +
> > > > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV, GMAC_PLLCLK_DIV_EN, 0);
> > > > +
> > > > +		switch (speed) {
> > > > +		case SPEED_1000:
> > > > +			div = rate / GMAC_GMII_RGMII_RATE;
> > > > +			break;
> > > > +		case SPEED_100:
> > > > +			div = rate / GMAC_MII_RATE;
> > > > +			break;
> > > > +		case SPEED_10:
> > > > +			div = rate * 10 / GMAC_MII_RATE;
> > > > +			break;
> > > > +		default:
> > > > +			dev_err(dwmac->dev, "invalid speed %u\n", speed);
> > > > +			return;
> > > > +		}
> > > > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > > > +				   GMAC_PLLCLK_DIV_MASK, GMAC_PLLCLK_DIV_NUM(div));
> > > > +
> > > > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > > > +				   GMAC_PLLCLK_DIV_EN, GMAC_PLLCLK_DIV_EN);
> > > 
> > > This chunk looks like a hard-coded implementation of the
> > > CLK_SET_RATE_GATE Tx-clocks rate setup which parental clock is the
> > > "stmmaceth" clock. I suggest to move it to the respective driver, add
> > > a "tx" clock to the bindings and use the common clock kernel API
> > > methods here only.
> > 
> > I did consider your solution before writing the code, here are the
> > reasons why I dropped it:
> > 
> 
> > There's no any clk IP here, the HW just puts several
> > gmac related control bits here, such as rx/tx delay, bypass, invert
> > interface choice, clk direction. 
> 
> You omitted the essential part of your code which I pointed out.
> 
> > From this point of view, it looks more
> > like a syscon rather than clk.
> 
> Toggling control bits is surely the syscon work. But gating a parental
> clock, settings up the parental clock _divider_ and ungating the clock
> back is the clock controller function. So it means your syscon is just
> a normal multi-function device, which one of the function is the clock
> controller.
> 
> It's not like your situation is unique. For instance in case of a SoC
> I was working with recently Clock Control Unit (CCU) was actually a
> multi-function device which had:
> 1. PLLs and Dividers supplying the clocks to the SoC components.

Hi Serge,

This is the big difference between your case and TH1520 gmac.
(PS: @Emil, I read your comments in another reply. IIUC, jh7110 puts a
real clk IP for gmac tx clock purpose)

However, There's no real clk IP in the TH1520 gmac related syscon, yep, div
and enable are some what clock related bits, but that's all, no more, no less.
So even in this case, another abstraction layer via. clk subsystem is still
preferred? IOW, a seperate clk driver for the gmac?

Thanks
> 
> 2. SoC components reset controller.
> 3. I2C-interface controller.
> 4. AXI-bus errors report registers.
> 5. PCIe-controller tunings (LTSSM, link up/down, etc)
> 6. SATA-controller tunings.
> 7. Full SoC reset controller (syscon reboot),
> 8. L2-cache tunings controller.
> with the sub-functions CSRs joint in a single space. In that case the
> PCIe-controller tunings and a lot of its reference clocks settings
> were intermixed in a single chunk of the registers. So I had to create
> a driver for the clocks anyway including all the PCIe reference
> clock and refer to the syscon in the PCIe-controller device node for
> the respective PCIe platform-specific tunings.
> 
> > 
> > Secondly, I see other SoCs did similar for this case, such as
> > dwmac-visconti, dwmac-meson8b, dwmac-ipq806x, dwmac-socfpga and so on.
> > They met similar issue as the above.
> 
> First I failed to find any clock-related things in the dwmac-socfpga

I believe the ptp ref clk related is just to enable the clk by toggling
corresponding bit. Anyway that's not important part here.

> driver looking in anyway as yours. Second the dwmac-meson8b driver
> creates a generic clock handler right in the driver. I don't think
> it's a great solution but at the very least it registers the clock
> handler in the kernel. But seeing the PROG_ETHERNET CSR is of 8 bytes
> long there (0xc8834540 0x8) and defined at looking random base address
> it's definitely a part of a Meson system controller which just
> directly passed to the device driver. It's not correct. That part
> should have been at least specified as a syscon too. Third the
> dwmac-visconti driver is not a good example seeing it defines some
> specific registers way away from the NIC CSR space. It's most likely a
> separate device like syscon. Fourth dwmac-ipq806x driver
> implementation looks indeed like yours.

> In anyway I don't say your solution is fully wrong. At the very least
> you have a syscon node defined. But it just makes you adding
> incomplete device/platform bindings. Your network device do have the
> Tx reference clock as a part of the separate system controller, but
> you have to omit it because of the syscon property. You do have a
> syscon node, but don't have its clock function exported. So AFAICS in
> your case things can be implemented in a more canonical way than they
> are now.
>

On Tue, Aug 29, 2023 at 11:17:45AM +0800, Jisheng Zhang wrote:
> On Mon, Aug 28, 2023 at 08:30:50PM +0300, Serge Semin wrote:
> > On Mon, Aug 28, 2023 at 11:41:47PM +0800, Jisheng Zhang wrote:
> > > On Mon, Aug 28, 2023 at 04:40:19PM +0300, Serge Semin wrote:
> > > > On Sun, Aug 27, 2023 at 05:17:10PM +0800, Jisheng Zhang wrote:
> > > > > Add dwmac glue driver to support the dwmac on the T-HEAD TH1520 SoC.
> > > > > 
> > > > > Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> > > > > ---
> > > > >  drivers/net/ethernet/stmicro/stmmac/Kconfig   |  11 +
> > > > >  drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
> > > > >  .../net/ethernet/stmicro/stmmac/dwmac-thead.c | 302 ++++++++++++++++++
> > > > >  3 files changed, 314 insertions(+)
> > > > >  create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > > > > 
> > > > > diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > > > index 06c6871f8788..1bf71804c270 100644
> > > > > --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > > > +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > > > @@ -216,6 +216,17 @@ config DWMAC_SUN8I
> > > > >  	  stmmac device driver. This driver is used for H3/A83T/A64
> > > > >  	  EMAC ethernet controller.
> > > > >  
> > > > > +config DWMAC_THEAD
> > > > > +	tristate "T-HEAD dwmac support"
> > > > > +	depends on OF && (ARCH_THEAD || COMPILE_TEST)
> > > > > +	select MFD_SYSCON
> > > > > +	help
> > > > > +	  Support for ethernet controllers on T-HEAD RISC-V SoCs
> > > > > +
> > > > > +	  This selects the T-HEAD platform specific glue layer support for
> > > > > +	  the stmmac device driver. This driver is used for T-HEAD TH1520
> > > > > +	  ethernet controller.
> > > > > +
> > > > >  config DWMAC_IMX8
> > > > >  	tristate "NXP IMX8 DWMAC support"
> > > > >  	default ARCH_MXC
> > > > > diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > > > index 5b57aee19267..d73171ed6ad7 100644
> > > > > --- a/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > > > +++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > > > @@ -27,6 +27,7 @@ obj-$(CONFIG_DWMAC_STI)		+= dwmac-sti.o
> > > > >  obj-$(CONFIG_DWMAC_STM32)	+= dwmac-stm32.o
> > > > >  obj-$(CONFIG_DWMAC_SUNXI)	+= dwmac-sunxi.o
> > > > >  obj-$(CONFIG_DWMAC_SUN8I)	+= dwmac-sun8i.o
> > > > > +obj-$(CONFIG_DWMAC_THEAD)	+= dwmac-thead.o
> > > > >  obj-$(CONFIG_DWMAC_DWC_QOS_ETH)	+= dwmac-dwc-qos-eth.o
> > > > >  obj-$(CONFIG_DWMAC_INTEL_PLAT)	+= dwmac-intel-plat.o
> > > > >  obj-$(CONFIG_DWMAC_GENERIC)	+= dwmac-generic.o
> > > > > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > > > > new file mode 100644
> > > > > index 000000000000..85135ef05906
> > > > > --- /dev/null
> > > > > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > > > > @@ -0,0 +1,302 @@
> > > > > +// SPDX-License-Identifier: GPL-2.0
> > > > > +/*
> > > > > + * T-HEAD DWMAC platform driver
> > > > > + *
> > > > > + * Copyright (C) 2021 Alibaba Group Holding Limited.
> > > > > + * Copyright (C) 2023 Jisheng Zhang <jszhang@kernel.org>
> > > > > + *
> > > > > + */
> > > > > +
> > > > > +#include <linux/bitfield.h>
> > > > > +#include <linux/mfd/syscon.h>
> > > > > +#include <linux/module.h>
> > > > > +#include <linux/of.h>
> > > > > +#include <linux/of_device.h>
> > > > > +#include <linux/of_net.h>
> > > > > +#include <linux/platform_device.h>
> > > > > +#include <linux/regmap.h>
> > > > > +
> > > > > +#include "stmmac_platform.h"
> > > > > +
> > > > > +#define GMAC_CLK_EN			0x00
> > > > > +#define  GMAC_TX_CLK_EN			BIT(1)
> > > > > +#define  GMAC_TX_CLK_N_EN		BIT(2)
> > > > > +#define  GMAC_TX_CLK_OUT_EN		BIT(3)
> > > > > +#define  GMAC_RX_CLK_EN			BIT(4)
> > > > > +#define  GMAC_RX_CLK_N_EN		BIT(5)
> > > > > +#define  GMAC_EPHY_REF_CLK_EN		BIT(6)
> > > > > +#define GMAC_RXCLK_DELAY_CTRL		0x04
> > > > > +#define  GMAC_RXCLK_BYPASS		BIT(15)
> > > > > +#define  GMAC_RXCLK_INVERT		BIT(14)
> > > > > +#define  GMAC_RXCLK_DELAY_MASK		GENMASK(4, 0)
> > > > > +#define  GMAC_RXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > > > > +#define GMAC_TXCLK_DELAY_CTRL		0x08
> > > > > +#define  GMAC_TXCLK_BYPASS		BIT(15)
> > > > > +#define  GMAC_TXCLK_INVERT		BIT(14)
> > > > > +#define  GMAC_TXCLK_DELAY_MASK		GENMASK(4, 0)
> > > > > +#define  GMAC_TXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > > > > +#define GMAC_PLLCLK_DIV			0x0c
> > > > > +#define  GMAC_PLLCLK_DIV_EN		BIT(31)
> > > > > +#define  GMAC_PLLCLK_DIV_MASK		GENMASK(7, 0)
> > > > > +#define  GMAC_PLLCLK_DIV_NUM(x)		FIELD_PREP(GMAC_PLLCLK_DIV_MASK, (x))
> > > > > +#define GMAC_GTXCLK_SEL			0x18
> > > > > +#define  GMAC_GTXCLK_SEL_PLL		BIT(0)
> > > > > +#define GMAC_INTF_CTRL			0x1c
> > > > > +#define  PHY_INTF_MASK			BIT(0)
> > > > > +#define  PHY_INTF_RGMII			FIELD_PREP(PHY_INTF_MASK, 1)
> > > > > +#define  PHY_INTF_MII_GMII		FIELD_PREP(PHY_INTF_MASK, 0)
> > > > > +#define GMAC_TXCLK_OEN			0x20
> > > > > +#define  TXCLK_DIR_MASK			BIT(0)
> > > > > +#define  TXCLK_DIR_OUTPUT		FIELD_PREP(TXCLK_DIR_MASK, 0)
> > > > > +#define  TXCLK_DIR_INPUT		FIELD_PREP(TXCLK_DIR_MASK, 1)
> > > > > +
> > > > > +#define GMAC_GMII_RGMII_RATE	125000000
> > > > > +#define GMAC_MII_RATE		25000000
> > > > > +
> > > > > +struct thead_dwmac {
> > > > > +	struct plat_stmmacenet_data *plat;
> > > > > +	struct regmap *apb_regmap;
> > > > > +	struct device *dev;
> > > > > +	u32 rx_delay;
> > > > > +	u32 tx_delay;
> > > > > +};
> > > > > +
> > > > > +static int thead_dwmac_set_phy_if(struct plat_stmmacenet_data *plat)
> > > > > +{
> > > > > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > > > > +	u32 phyif;
> > > > > +
> > > > > +	switch (plat->interface) {
> > > > > +	case PHY_INTERFACE_MODE_MII:
> > > > > +		phyif = PHY_INTF_MII_GMII;
> > > > > +		break;
> > > > > +	case PHY_INTERFACE_MODE_RGMII:
> > > > > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > > > > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > > > > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > > > > +		phyif = PHY_INTF_RGMII;
> > > > > +		break;
> > > > > +	default:
> > > > > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > > > +			plat->interface);
> > > > > +		return -EINVAL;
> > > > > +	};
> > > > > +
> > > > > +	regmap_write(dwmac->apb_regmap, GMAC_INTF_CTRL, phyif);
> > > > > +
> > > > > +	return 0;
> > > > > +}
> > > > > +
> > > > > +static int thead_dwmac_set_txclk_dir(struct plat_stmmacenet_data *plat)
> > > > > +{
> > > > > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > > > > +	u32 txclk_dir;
> > > > > +
> > > > > +	switch (plat->interface) {
> > > > > +	case PHY_INTERFACE_MODE_MII:
> > > > > +		txclk_dir = TXCLK_DIR_INPUT;
> > > > > +		break;
> > > > > +	case PHY_INTERFACE_MODE_RGMII:
> > > > > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > > > > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > > > > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > > > > +		txclk_dir = TXCLK_DIR_OUTPUT;
> > > > > +		break;
> > > > > +	default:
> > > > > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > > > +			plat->interface);
> > > > > +		return -EINVAL;
> > > > > +	};
> > > > > +
> > > > > +	regmap_write(dwmac->apb_regmap, GMAC_TXCLK_OEN, txclk_dir);
> > > > > +
> > > > > +	return 0;
> > > > > +}
> > > > > +
> > > > > +static void thead_dwmac_fix_speed(void *priv, unsigned int speed, unsigned int mode)
> > > > > +{
> > > > > +	struct thead_dwmac *dwmac = priv;
> > > > > +	struct plat_stmmacenet_data *plat = dwmac->plat;
> > > > > +	unsigned long rate;
> > > > > +	u32 div;
> > > > > +
> > > > > +	switch (plat->interface) {
> > > > > +	/* For MII, rxc/txc is provided by phy */
> > > > > +	case PHY_INTERFACE_MODE_MII:
> > > > > +		return;
> > > > > +
> > > > > +	case PHY_INTERFACE_MODE_RGMII:
> > > > > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > > > > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > > > > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > > > 
> > > > > +		rate = clk_get_rate(plat->stmmac_clk);
> > > > > +		if (!rate || rate % GMAC_GMII_RGMII_RATE != 0 ||
> > > > > +		    rate % GMAC_MII_RATE != 0) {
> > > > > +			dev_err(dwmac->dev, "invalid gmac rate %ld\n", rate);
> > > > > +			return;
> > > > > +		}
> > > > > +
> > > > > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV, GMAC_PLLCLK_DIV_EN, 0);
> > > > > +
> > > > > +		switch (speed) {
> > > > > +		case SPEED_1000:
> > > > > +			div = rate / GMAC_GMII_RGMII_RATE;
> > > > > +			break;
> > > > > +		case SPEED_100:
> > > > > +			div = rate / GMAC_MII_RATE;
> > > > > +			break;
> > > > > +		case SPEED_10:
> > > > > +			div = rate * 10 / GMAC_MII_RATE;
> > > > > +			break;
> > > > > +		default:
> > > > > +			dev_err(dwmac->dev, "invalid speed %u\n", speed);
> > > > > +			return;
> > > > > +		}
> > > > > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > > > > +				   GMAC_PLLCLK_DIV_MASK, GMAC_PLLCLK_DIV_NUM(div));
> > > > > +
> > > > > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > > > > +				   GMAC_PLLCLK_DIV_EN, GMAC_PLLCLK_DIV_EN);
> > > > 
> > > > This chunk looks like a hard-coded implementation of the
> > > > CLK_SET_RATE_GATE Tx-clocks rate setup which parental clock is the
> > > > "stmmaceth" clock. I suggest to move it to the respective driver, add
> > > > a "tx" clock to the bindings and use the common clock kernel API
> > > > methods here only.
> > > 
> > > I did consider your solution before writing the code, here are the
> > > reasons why I dropped it:
> > > 
> > 
> > > There's no any clk IP here, the HW just puts several
> > > gmac related control bits here, such as rx/tx delay, bypass, invert
> > > interface choice, clk direction. 
> > 
> > You omitted the essential part of your code which I pointed out.
> > 
> > > From this point of view, it looks more
> > > like a syscon rather than clk.
> > 

> > Toggling control bits is surely the syscon work. But gating a parental
> > clock, settings up the parental clock _divider_ and ungating the clock
> > back is the clock controller function. So it means your syscon is just
> > a normal multi-function device, which one of the function is the clock
> > controller.
> > 
> > It's not like your situation is unique. For instance in case of a SoC
> > I was working with recently Clock Control Unit (CCU) was actually a
> > multi-function device which had:
> > 1. PLLs and Dividers supplying the clocks to the SoC components.
> 
> Hi Serge,
> 
> This is the big difference between your case and TH1520 gmac.

AFAICS my PCIe-part of the syscon is a similar story as your GMAC
CSRs: enabled/disable several clock gates, setup a ref-clock divider,
multiple flags with reset function and multiple flags/fields for the
PCIe-controller tunings. All of that intermixed in a few registers. A
similar thing was for the SATA-controller.

> (PS: @Emil, I read your comments in another reply. IIUC, jh7110 puts a
> real clk IP for gmac tx clock purpose)
> 

> However, There's no real clk IP in the TH1520 gmac related syscon, yep, div
> and enable are some what clock related bits, but that's all, no more, no less.

These bits/fields are the clock-controller function of the syscon.
Based on that your syscon is a multi-functional device which support
the GMAC tunings and controls a reference clock gating/dividing.  The
outputs from the clock gate and divider gets to be supplied to the
TH1520 GMAC.

BTW Seeing you have only 0x20 bytes utilized in the glue driver I
guess those registers chunk is a part of a bigger CSR space. Is it?

> So even in this case, another abstraction layer via. clk subsystem is still
> preferred? IOW, a seperate clk driver for the gmac?

That's what I was told in a situation when I was trying to use a
syscon to switch between the two parental clocks:
https://lore.kernel.org/linux-ide/20220517201332.GB1462130-robh@kernel.org/

In your case IMO it is more preferred at the very least because it
gives a more correct device description. Your bindings currently do
not define the Tx/Rx reference clocks meanwhile the TH1520 GMAC do
have them.

-Serge(y)

> 
> Thanks
> > 
> > 2. SoC components reset controller.
> > 3. I2C-interface controller.
> > 4. AXI-bus errors report registers.
> > 5. PCIe-controller tunings (LTSSM, link up/down, etc)
> > 6. SATA-controller tunings.
> > 7. Full SoC reset controller (syscon reboot),
> > 8. L2-cache tunings controller.
> > with the sub-functions CSRs joint in a single space. In that case the
> > PCIe-controller tunings and a lot of its reference clocks settings
> > were intermixed in a single chunk of the registers. So I had to create
> > a driver for the clocks anyway including all the PCIe reference
> > clock and refer to the syscon in the PCIe-controller device node for
> > the respective PCIe platform-specific tunings.
> > 
> > > 
> > > Secondly, I see other SoCs did similar for this case, such as
> > > dwmac-visconti, dwmac-meson8b, dwmac-ipq806x, dwmac-socfpga and so on.
> > > They met similar issue as the above.
> > 
> > First I failed to find any clock-related things in the dwmac-socfpga
> 
> I believe the ptp ref clk related is just to enable the clk by toggling
> corresponding bit. Anyway that's not important part here.
> 
> > driver looking in anyway as yours. Second the dwmac-meson8b driver
> > creates a generic clock handler right in the driver. I don't think
> > it's a great solution but at the very least it registers the clock
> > handler in the kernel. But seeing the PROG_ETHERNET CSR is of 8 bytes
> > long there (0xc8834540 0x8) and defined at looking random base address
> > it's definitely a part of a Meson system controller which just
> > directly passed to the device driver. It's not correct. That part
> > should have been at least specified as a syscon too. Third the
> > dwmac-visconti driver is not a good example seeing it defines some
> > specific registers way away from the NIC CSR space. It's most likely a
> > separate device like syscon. Fourth dwmac-ipq806x driver
> > implementation looks indeed like yours.
> 
> > In anyway I don't say your solution is fully wrong. At the very least
> > you have a syscon node defined. But it just makes you adding
> > incomplete device/platform bindings. Your network device do have the
> > Tx reference clock as a part of the separate system controller, but
> > you have to omit it because of the syscon property. You do have a
> > syscon node, but don't have its clock function exported. So AFAICS in
> > your case things can be implemented in a more canonical way than they
> > are now.
> >

On Tue, Aug 29, 2023 at 01:07:39PM +0300, Serge Semin wrote:
> On Tue, Aug 29, 2023 at 11:17:45AM +0800, Jisheng Zhang wrote:
> > On Mon, Aug 28, 2023 at 08:30:50PM +0300, Serge Semin wrote:
> > > On Mon, Aug 28, 2023 at 11:41:47PM +0800, Jisheng Zhang wrote:
> > > > On Mon, Aug 28, 2023 at 04:40:19PM +0300, Serge Semin wrote:
> > > > > On Sun, Aug 27, 2023 at 05:17:10PM +0800, Jisheng Zhang wrote:
> > > > > > Add dwmac glue driver to support the dwmac on the T-HEAD TH1520 SoC.
> > > > > > 
> > > > > > Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> > > > > > ---
> > > > > >  drivers/net/ethernet/stmicro/stmmac/Kconfig   |  11 +
> > > > > >  drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
> > > > > >  .../net/ethernet/stmicro/stmmac/dwmac-thead.c | 302 ++++++++++++++++++
> > > > > >  3 files changed, 314 insertions(+)
> > > > > >  create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > > > > > 
> > > > > > diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > > > > index 06c6871f8788..1bf71804c270 100644
> > > > > > --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > > > > +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > > > > > @@ -216,6 +216,17 @@ config DWMAC_SUN8I
> > > > > >  	  stmmac device driver. This driver is used for H3/A83T/A64
> > > > > >  	  EMAC ethernet controller.
> > > > > >  
> > > > > > +config DWMAC_THEAD
> > > > > > +	tristate "T-HEAD dwmac support"
> > > > > > +	depends on OF && (ARCH_THEAD || COMPILE_TEST)
> > > > > > +	select MFD_SYSCON
> > > > > > +	help
> > > > > > +	  Support for ethernet controllers on T-HEAD RISC-V SoCs
> > > > > > +
> > > > > > +	  This selects the T-HEAD platform specific glue layer support for
> > > > > > +	  the stmmac device driver. This driver is used for T-HEAD TH1520
> > > > > > +	  ethernet controller.
> > > > > > +
> > > > > >  config DWMAC_IMX8
> > > > > >  	tristate "NXP IMX8 DWMAC support"
> > > > > >  	default ARCH_MXC
> > > > > > diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > > > > index 5b57aee19267..d73171ed6ad7 100644
> > > > > > --- a/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > > > > +++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > > > > > @@ -27,6 +27,7 @@ obj-$(CONFIG_DWMAC_STI)		+= dwmac-sti.o
> > > > > >  obj-$(CONFIG_DWMAC_STM32)	+= dwmac-stm32.o
> > > > > >  obj-$(CONFIG_DWMAC_SUNXI)	+= dwmac-sunxi.o
> > > > > >  obj-$(CONFIG_DWMAC_SUN8I)	+= dwmac-sun8i.o
> > > > > > +obj-$(CONFIG_DWMAC_THEAD)	+= dwmac-thead.o
> > > > > >  obj-$(CONFIG_DWMAC_DWC_QOS_ETH)	+= dwmac-dwc-qos-eth.o
> > > > > >  obj-$(CONFIG_DWMAC_INTEL_PLAT)	+= dwmac-intel-plat.o
> > > > > >  obj-$(CONFIG_DWMAC_GENERIC)	+= dwmac-generic.o
> > > > > > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > > > > > new file mode 100644
> > > > > > index 000000000000..85135ef05906
> > > > > > --- /dev/null
> > > > > > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > > > > > @@ -0,0 +1,302 @@
> > > > > > +// SPDX-License-Identifier: GPL-2.0
> > > > > > +/*
> > > > > > + * T-HEAD DWMAC platform driver
> > > > > > + *
> > > > > > + * Copyright (C) 2021 Alibaba Group Holding Limited.
> > > > > > + * Copyright (C) 2023 Jisheng Zhang <jszhang@kernel.org>
> > > > > > + *
> > > > > > + */
> > > > > > +
> > > > > > +#include <linux/bitfield.h>
> > > > > > +#include <linux/mfd/syscon.h>
> > > > > > +#include <linux/module.h>
> > > > > > +#include <linux/of.h>
> > > > > > +#include <linux/of_device.h>
> > > > > > +#include <linux/of_net.h>
> > > > > > +#include <linux/platform_device.h>
> > > > > > +#include <linux/regmap.h>
> > > > > > +
> > > > > > +#include "stmmac_platform.h"
> > > > > > +
> > > > > > +#define GMAC_CLK_EN			0x00
> > > > > > +#define  GMAC_TX_CLK_EN			BIT(1)
> > > > > > +#define  GMAC_TX_CLK_N_EN		BIT(2)
> > > > > > +#define  GMAC_TX_CLK_OUT_EN		BIT(3)
> > > > > > +#define  GMAC_RX_CLK_EN			BIT(4)
> > > > > > +#define  GMAC_RX_CLK_N_EN		BIT(5)
> > > > > > +#define  GMAC_EPHY_REF_CLK_EN		BIT(6)
> > > > > > +#define GMAC_RXCLK_DELAY_CTRL		0x04
> > > > > > +#define  GMAC_RXCLK_BYPASS		BIT(15)
> > > > > > +#define  GMAC_RXCLK_INVERT		BIT(14)
> > > > > > +#define  GMAC_RXCLK_DELAY_MASK		GENMASK(4, 0)
> > > > > > +#define  GMAC_RXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > > > > > +#define GMAC_TXCLK_DELAY_CTRL		0x08
> > > > > > +#define  GMAC_TXCLK_BYPASS		BIT(15)
> > > > > > +#define  GMAC_TXCLK_INVERT		BIT(14)
> > > > > > +#define  GMAC_TXCLK_DELAY_MASK		GENMASK(4, 0)
> > > > > > +#define  GMAC_TXCLK_DELAY_VAL(x)	FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > > > > > +#define GMAC_PLLCLK_DIV			0x0c
> > > > > > +#define  GMAC_PLLCLK_DIV_EN		BIT(31)
> > > > > > +#define  GMAC_PLLCLK_DIV_MASK		GENMASK(7, 0)
> > > > > > +#define  GMAC_PLLCLK_DIV_NUM(x)		FIELD_PREP(GMAC_PLLCLK_DIV_MASK, (x))
> > > > > > +#define GMAC_GTXCLK_SEL			0x18
> > > > > > +#define  GMAC_GTXCLK_SEL_PLL		BIT(0)
> > > > > > +#define GMAC_INTF_CTRL			0x1c
> > > > > > +#define  PHY_INTF_MASK			BIT(0)
> > > > > > +#define  PHY_INTF_RGMII			FIELD_PREP(PHY_INTF_MASK, 1)
> > > > > > +#define  PHY_INTF_MII_GMII		FIELD_PREP(PHY_INTF_MASK, 0)
> > > > > > +#define GMAC_TXCLK_OEN			0x20
> > > > > > +#define  TXCLK_DIR_MASK			BIT(0)
> > > > > > +#define  TXCLK_DIR_OUTPUT		FIELD_PREP(TXCLK_DIR_MASK, 0)
> > > > > > +#define  TXCLK_DIR_INPUT		FIELD_PREP(TXCLK_DIR_MASK, 1)
> > > > > > +
> > > > > > +#define GMAC_GMII_RGMII_RATE	125000000
> > > > > > +#define GMAC_MII_RATE		25000000
> > > > > > +
> > > > > > +struct thead_dwmac {
> > > > > > +	struct plat_stmmacenet_data *plat;
> > > > > > +	struct regmap *apb_regmap;
> > > > > > +	struct device *dev;
> > > > > > +	u32 rx_delay;
> > > > > > +	u32 tx_delay;
> > > > > > +};
> > > > > > +
> > > > > > +static int thead_dwmac_set_phy_if(struct plat_stmmacenet_data *plat)
> > > > > > +{
> > > > > > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > > > > > +	u32 phyif;
> > > > > > +
> > > > > > +	switch (plat->interface) {
> > > > > > +	case PHY_INTERFACE_MODE_MII:
> > > > > > +		phyif = PHY_INTF_MII_GMII;
> > > > > > +		break;
> > > > > > +	case PHY_INTERFACE_MODE_RGMII:
> > > > > > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > > > > > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > > > > > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > > > > > +		phyif = PHY_INTF_RGMII;
> > > > > > +		break;
> > > > > > +	default:
> > > > > > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > > > > +			plat->interface);
> > > > > > +		return -EINVAL;
> > > > > > +	};
> > > > > > +
> > > > > > +	regmap_write(dwmac->apb_regmap, GMAC_INTF_CTRL, phyif);
> > > > > > +
> > > > > > +	return 0;
> > > > > > +}
> > > > > > +
> > > > > > +static int thead_dwmac_set_txclk_dir(struct plat_stmmacenet_data *plat)
> > > > > > +{
> > > > > > +	struct thead_dwmac *dwmac = plat->bsp_priv;
> > > > > > +	u32 txclk_dir;
> > > > > > +
> > > > > > +	switch (plat->interface) {
> > > > > > +	case PHY_INTERFACE_MODE_MII:
> > > > > > +		txclk_dir = TXCLK_DIR_INPUT;
> > > > > > +		break;
> > > > > > +	case PHY_INTERFACE_MODE_RGMII:
> > > > > > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > > > > > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > > > > > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > > > > > +		txclk_dir = TXCLK_DIR_OUTPUT;
> > > > > > +		break;
> > > > > > +	default:
> > > > > > +		dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > > > > > +			plat->interface);
> > > > > > +		return -EINVAL;
> > > > > > +	};
> > > > > > +
> > > > > > +	regmap_write(dwmac->apb_regmap, GMAC_TXCLK_OEN, txclk_dir);
> > > > > > +
> > > > > > +	return 0;
> > > > > > +}
> > > > > > +
> > > > > > +static void thead_dwmac_fix_speed(void *priv, unsigned int speed, unsigned int mode)
> > > > > > +{
> > > > > > +	struct thead_dwmac *dwmac = priv;
> > > > > > +	struct plat_stmmacenet_data *plat = dwmac->plat;
> > > > > > +	unsigned long rate;
> > > > > > +	u32 div;
> > > > > > +
> > > > > > +	switch (plat->interface) {
> > > > > > +	/* For MII, rxc/txc is provided by phy */
> > > > > > +	case PHY_INTERFACE_MODE_MII:
> > > > > > +		return;
> > > > > > +
> > > > > > +	case PHY_INTERFACE_MODE_RGMII:
> > > > > > +	case PHY_INTERFACE_MODE_RGMII_ID:
> > > > > > +	case PHY_INTERFACE_MODE_RGMII_RXID:
> > > > > > +	case PHY_INTERFACE_MODE_RGMII_TXID:
> > > > > 
> > > > > > +		rate = clk_get_rate(plat->stmmac_clk);
> > > > > > +		if (!rate || rate % GMAC_GMII_RGMII_RATE != 0 ||
> > > > > > +		    rate % GMAC_MII_RATE != 0) {
> > > > > > +			dev_err(dwmac->dev, "invalid gmac rate %ld\n", rate);
> > > > > > +			return;
> > > > > > +		}
> > > > > > +
> > > > > > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV, GMAC_PLLCLK_DIV_EN, 0);
> > > > > > +
> > > > > > +		switch (speed) {
> > > > > > +		case SPEED_1000:
> > > > > > +			div = rate / GMAC_GMII_RGMII_RATE;
> > > > > > +			break;
> > > > > > +		case SPEED_100:
> > > > > > +			div = rate / GMAC_MII_RATE;
> > > > > > +			break;
> > > > > > +		case SPEED_10:
> > > > > > +			div = rate * 10 / GMAC_MII_RATE;
> > > > > > +			break;
> > > > > > +		default:
> > > > > > +			dev_err(dwmac->dev, "invalid speed %u\n", speed);
> > > > > > +			return;
> > > > > > +		}
> > > > > > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > > > > > +				   GMAC_PLLCLK_DIV_MASK, GMAC_PLLCLK_DIV_NUM(div));
> > > > > > +
> > > > > > +		regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > > > > > +				   GMAC_PLLCLK_DIV_EN, GMAC_PLLCLK_DIV_EN);
> > > > > 
> > > > > This chunk looks like a hard-coded implementation of the
> > > > > CLK_SET_RATE_GATE Tx-clocks rate setup which parental clock is the
> > > > > "stmmaceth" clock. I suggest to move it to the respective driver, add
> > > > > a "tx" clock to the bindings and use the common clock kernel API
> > > > > methods here only.
> > > > 
> > > > I did consider your solution before writing the code, here are the
> > > > reasons why I dropped it:
> > > > 
> > > 
> > > > There's no any clk IP here, the HW just puts several
> > > > gmac related control bits here, such as rx/tx delay, bypass, invert
> > > > interface choice, clk direction. 
> > > 
> > > You omitted the essential part of your code which I pointed out.
> > > 
> > > > From this point of view, it looks more
> > > > like a syscon rather than clk.
> > > 
> 
> > > Toggling control bits is surely the syscon work. But gating a parental
> > > clock, settings up the parental clock _divider_ and ungating the clock
> > > back is the clock controller function. So it means your syscon is just
> > > a normal multi-function device, which one of the function is the clock
> > > controller.
> > > 
> > > It's not like your situation is unique. For instance in case of a SoC
> > > I was working with recently Clock Control Unit (CCU) was actually a
> > > multi-function device which had:
> > > 1. PLLs and Dividers supplying the clocks to the SoC components.
> > 
> > Hi Serge,
> > 
> > This is the big difference between your case and TH1520 gmac.
> 
> AFAICS my PCIe-part of the syscon is a similar story as your GMAC
> CSRs: enabled/disable several clock gates, setup a ref-clock divider,
> multiple flags with reset function and multiple flags/fields for the
> PCIe-controller tunings. All of that intermixed in a few registers. A
> similar thing was for the SATA-controller.
> 
> > (PS: @Emil, I read your comments in another reply. IIUC, jh7110 puts a
> > real clk IP for gmac tx clock purpose)
> > 
> 
> > However, There's no real clk IP in the TH1520 gmac related syscon, yep, div
> > and enable are some what clock related bits, but that's all, no more, no less.
> 
> These bits/fields are the clock-controller function of the syscon.
> Based on that your syscon is a multi-functional device which support
> the GMAC tunings and controls a reference clock gating/dividing.  The
> outputs from the clock gate and divider gets to be supplied to the
> TH1520 GMAC.
> 
> BTW Seeing you have only 0x20 bytes utilized in the glue driver I
> guess those registers chunk is a part of a bigger CSR space. Is it?

Nope, the 4KB reg space is dedicated to gmac control, and isn't
a part of a big reg space, and only 0~0x20 of the address space is used.

> 
> > So even in this case, another abstraction layer via. clk subsystem is still
> > preferred? IOW, a seperate clk driver for the gmac?
> 
> That's what I was told in a situation when I was trying to use a
> syscon to switch between the two parental clocks:
> https://lore.kernel.org/linux-ide/20220517201332.GB1462130-robh@kernel.org/
> 
> In your case IMO it is more preferred at the very least because it
> gives a more correct device description. Your bindings currently do
> not define the Tx/Rx reference clocks meanwhile the TH1520 GMAC do
> have them.
> 

Thank you, I will modify the code towards clk direction.

On Sun, Aug 27, 2023 at 05:17:09PM +0800, Jisheng Zhang wrote:
>Add the dwmac driver support for T-HEAD TH1520 SoC.
>
>Since the clk part isn't mainlined, so SoC dts(i) changes are not
>included in this series. However, it can be tested by using fixed-clock.
>
>Since v1:
>  - rebase on the lastest net-next
>  - collect Reviewed-by tag
>  - address Krzysztof's comment of the dt binding
>  - fix "div is not initialised" issue pointed out by Simon
>
>Jisheng Zhang (3):
>  dt-bindings: net: snps,dwmac: allow dwmac-3.70a to set pbl properties
>  dt-bindings: net: add T-HEAD dwmac support
>  net: stmmac: add glue layer for T-HEAD TH1520 SoC
>
> .../devicetree/bindings/net/snps,dwmac.yaml   |   2 +
> .../devicetree/bindings/net/thead,dwmac.yaml  |  77 +++++
> drivers/net/ethernet/stmicro/stmmac/Kconfig   |  11 +
> drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
> .../net/ethernet/stmicro/stmmac/dwmac-thead.c | 302 ++++++++++++++++++
> 5 files changed, 393 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/net/thead,dwmac.yaml

I would like to try this patch on my LicheePi 4A board, 
but I don't know how to modify the dts file.
Could you please share your modifications to the dts file?
Thank you very much.

Best regards,
Jiexun Wang