[v2,3/6] PCI: amlogic: meson: Add support for G12A

Add support for the Amlogic G12A SoC using a separate shared PHY.

This adds support for fetching a PHY phandle and call the PHY init,
reset and power on/off calls instead of writing in the PHY register or
toggling the PHY reset line.

The MIPI clock and the PHY memory resource are only required for the
Amlogic AXG SoC PCIe PHY setup, thus these elements are ignored for
the Amlogic G12A having a separate shared PHY.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
 drivers/pci/controller/dwc/pci-meson.c | 128 ++++++++++++++++++++-----
 1 file changed, 105 insertions(+), 23 deletions(-)

On Mon, Sep 16, 2019 at 02:50:19PM +0200, Neil Armstrong wrote:
> Add support for the Amlogic G12A SoC using a separate shared PHY.
> 
> This adds support for fetching a PHY phandle and call the PHY init,
> reset and power on/off calls instead of writing in the PHY register or
> toggling the PHY reset line.
> 
> The MIPI clock and the PHY memory resource are only required for the
> Amlogic AXG SoC PCIe PHY setup, thus these elements are ignored for
> the Amlogic G12A having a separate shared PHY.
> 
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
> ---
>  drivers/pci/controller/dwc/pci-meson.c | 128 ++++++++++++++++++++-----
>  1 file changed, 105 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-meson.c b/drivers/pci/controller/dwc/pci-meson.c
> index ab79990798f8..3772b02a5c55 100644
> --- a/drivers/pci/controller/dwc/pci-meson.c
> +++ b/drivers/pci/controller/dwc/pci-meson.c
> @@ -16,6 +16,7 @@
>  #include <linux/reset.h>
>  #include <linux/resource.h>
>  #include <linux/types.h>
> +#include <linux/phy/phy.h>
>  
>  #include "pcie-designware.h"
>  
> @@ -96,12 +97,18 @@ struct meson_pcie_rc_reset {
>  	struct reset_control *apb;
>  };
>  
> +struct meson_pcie_param {
> +	bool has_shared_phy;
> +};
> +
>  struct meson_pcie {
>  	struct dw_pcie pci;
>  	struct meson_pcie_mem_res mem_res;
>  	struct meson_pcie_clk_res clk_res;
>  	struct meson_pcie_rc_reset mrst;
>  	struct gpio_desc *reset_gpio;
> +	struct phy *phy;
> +	const struct meson_pcie_param *param;
>  };
>  
>  static struct reset_control *meson_pcie_get_reset(struct meson_pcie *mp,
> @@ -123,10 +130,12 @@ static int meson_pcie_get_resets(struct meson_pcie *mp)
>  {
>  	struct meson_pcie_rc_reset *mrst = &mp->mrst;
>  
> -	mrst->phy = meson_pcie_get_reset(mp, "phy", PCIE_SHARED_RESET);
> -	if (IS_ERR(mrst->phy))
> -		return PTR_ERR(mrst->phy);
> -	reset_control_deassert(mrst->phy);
> +	if (!mp->param->has_shared_phy) {
> +		mrst->phy = meson_pcie_get_reset(mp, "phy", PCIE_SHARED_RESET);
> +		if (IS_ERR(mrst->phy))
> +			return PTR_ERR(mrst->phy);
> +		reset_control_deassert(mrst->phy);
> +	}
>  
>  	mrst->port = meson_pcie_get_reset(mp, "port", PCIE_NORMAL_RESET);
>  	if (IS_ERR(mrst->port))
> @@ -180,27 +189,52 @@ static int meson_pcie_get_mems(struct platform_device *pdev,
>  	if (IS_ERR(mp->mem_res.cfg_base))
>  		return PTR_ERR(mp->mem_res.cfg_base);
>  
> -	/* Meson SoC has two PCI controllers use same phy register*/
> -	mp->mem_res.phy_base = meson_pcie_get_mem_shared(pdev, mp, "phy");
> -	if (IS_ERR(mp->mem_res.phy_base))
> -		return PTR_ERR(mp->mem_res.phy_base);
> +	/* Meson AXG SoC has two PCI controllers use same phy register */
> +	if (!mp->param->has_shared_phy) {
> +		mp->mem_res.phy_base =
> +			meson_pcie_get_mem_shared(pdev, mp, "phy");
> +		if (IS_ERR(mp->mem_res.phy_base))
> +			return PTR_ERR(mp->mem_res.phy_base);
> +	}
>  
>  	return 0;
>  }
>  
> -static void meson_pcie_power_on(struct meson_pcie *mp)
> +static int meson_pcie_power_on(struct meson_pcie *mp)
>  {
> -	writel(MESON_PCIE_PHY_POWERUP, mp->mem_res.phy_base);
> +	int ret = 0;
> +
> +	if (mp->param->has_shared_phy) {
> +		ret = phy_init(mp->phy);
> +		if (ret)
> +			return ret;
> +
> +		ret = phy_power_on(mp->phy);
> +		if (ret) {
> +			phy_exit(mp->phy);
> +			return ret;
> +		}
> +	} else
> +		writel(MESON_PCIE_PHY_POWERUP, mp->mem_res.phy_base);
> +
> +	return 0;
>  }
>  
> -static void meson_pcie_reset(struct meson_pcie *mp)
> +static int meson_pcie_reset(struct meson_pcie *mp)
>  {
>  	struct meson_pcie_rc_reset *mrst = &mp->mrst;
> -
> -	reset_control_assert(mrst->phy);
> -	udelay(PCIE_RESET_DELAY);
> -	reset_control_deassert(mrst->phy);
> -	udelay(PCIE_RESET_DELAY);
> +	int ret = 0;
> +
> +	if (mp->param->has_shared_phy) {
> +		ret = phy_reset(mp->phy);
> +		if (ret)
> +			return ret;
> +	} else {
> +		reset_control_assert(mrst->phy);
> +		udelay(PCIE_RESET_DELAY);
> +		reset_control_deassert(mrst->phy);
> +		udelay(PCIE_RESET_DELAY);
> +	}
>  
>  	reset_control_assert(mrst->port);
>  	reset_control_assert(mrst->apb);
> @@ -208,6 +242,8 @@ static void meson_pcie_reset(struct meson_pcie *mp)
>  	reset_control_deassert(mrst->port);
>  	reset_control_deassert(mrst->apb);
>  	udelay(PCIE_RESET_DELAY);
> +
> +	return 0;
>  }
>  
>  static inline struct clk *meson_pcie_probe_clock(struct device *dev,
> @@ -250,9 +286,11 @@ static int meson_pcie_probe_clocks(struct meson_pcie *mp)
>  	if (IS_ERR(res->port_clk))
>  		return PTR_ERR(res->port_clk);
>  
> -	res->mipi_gate = meson_pcie_probe_clock(dev, "mipi", 0);
> -	if (IS_ERR(res->mipi_gate))
> -		return PTR_ERR(res->mipi_gate);
> +	if (!mp->param->has_shared_phy) {
> +		res->mipi_gate = meson_pcie_probe_clock(dev, "mipi", 0);
> +		if (IS_ERR(res->mipi_gate))
> +			return PTR_ERR(res->mipi_gate);
> +	}
>  
>  	res->general_clk = meson_pcie_probe_clock(dev, "general", 0);
>  	if (IS_ERR(res->general_clk))
> @@ -524,6 +562,7 @@ static const struct dw_pcie_ops dw_pcie_ops = {
>  
>  static int meson_pcie_probe(struct platform_device *pdev)
>  {
> +	const struct meson_pcie_param *match_data;
>  	struct device *dev = &pdev->dev;
>  	struct dw_pcie *pci;
>  	struct meson_pcie *mp;
> @@ -537,6 +576,19 @@ static int meson_pcie_probe(struct platform_device *pdev)
>  	pci->dev = dev;
>  	pci->ops = &dw_pcie_ops;
>  
> +	match_data = of_device_get_match_data(dev);
> +	if (!match_data) {
> +		dev_err(dev, "failed to get match data\n");
> +		return -ENODEV;
> +	}
> +	mp->param = match_data;
> +
> +	if (mp->param->has_shared_phy) {
> +		mp->phy = devm_phy_get(dev, "pcie");
> +		if (IS_ERR(mp->phy))
> +			return PTR_ERR(mp->phy);
> +	}
> +
>  	mp->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
>  	if (IS_ERR(mp->reset_gpio)) {
>  		dev_err(dev, "get reset gpio failed\n");
> @@ -555,13 +607,22 @@ static int meson_pcie_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> -	meson_pcie_power_on(mp);
> -	meson_pcie_reset(mp);
> +	ret = meson_pcie_power_on(mp);
> +	if (ret) {
> +		dev_err(dev, "phy power on failed, %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = meson_pcie_reset(mp);
> +	if (ret) {
> +		dev_err(dev, "reset failed, %d\n", ret);
> +		goto err_phy;
> +	}
>  
>  	ret = meson_pcie_probe_clocks(mp);
>  	if (ret) {
>  		dev_err(dev, "init clock resources failed, %d\n", ret);
> -		return ret;
> +		goto err_phy;
>  	}
>  
>  	platform_set_drvdata(pdev, mp);
> @@ -569,15 +630,36 @@ static int meson_pcie_probe(struct platform_device *pdev)
>  	ret = meson_add_pcie_port(mp, pdev);
>  	if (ret < 0) {
>  		dev_err(dev, "Add PCIe port failed, %d\n", ret);
> -		return ret;
> +		goto err_phy;
>  	}
>  
>  	return 0;
> +
> +err_phy:
> +	if (mp->param->has_shared_phy) {
> +		phy_power_off(mp->phy);
> +		phy_exit(mp->phy);
> +	}

Interestingly for AXG, if the probe fails we don't seem to do the opposite
of MESON_PCIE_PHY_POWERUP. Though I can see this is a pre-existing issue that
has little impact and probably rarely gets hit, so:

Reviewed-by: Andrew Murray <andrew.murray@arm.com>

However it would be *super really nice* to write a meson_pcie_power_off that
mirrors meson_pcie_power_on that you could call here instead.

Thanks,

Andrew Murray 

> +
> +	return ret;
>  }
>  
> +static struct meson_pcie_param meson_pcie_axg_param = {
> +	.has_shared_phy = false,
> +};
> +
> +static struct meson_pcie_param meson_pcie_g12a_param = {
> +	.has_shared_phy = true,
> +};
> +
>  static const struct of_device_id meson_pcie_of_match[] = {
>  	{
>  		.compatible = "amlogic,axg-pcie",
> +		.data = &meson_pcie_axg_param,
> +	},
> +	{
> +		.compatible = "amlogic,g12a-pcie",
> +		.data = &meson_pcie_g12a_param,
>  	},
>  	{},
>  };
> -- 
> 2.22.0
>