diff mbox series

[v2,16/22] sunxi: add R528/T113-s3/D1(s) DRAM initialisation code

Message ID 20230928215455.28094-17-andre.przywara@arm.com
State Accepted
Delegated to: Andre Przywara
Headers show
Series sunxi: Allwinner T113s support | expand

Commit Message

Andre Przywara Sept. 28, 2023, 9:54 p.m. UTC
The Allwinner R528/T113-s/D1/D1s SoCs all share the same die, so use the
same DRAM initialisation code.
Make use of prior art here and lift some code from awboot[1], which
carried init code based on earlier decompilation efforts, but with a
GPL2 license tag.
This code has been heavily reworked and cleaned up, to match previous
DRAM routines for other SoCs, and also to be closer to U-Boot's coding
style and support routines.
The actual DRAM chip timing parameters are included in the main file,
since they cover all DRAM types, and are protected by a new Kconfig
CONFIG_SUNXI_DRAM_TYPE symbol, which allows the compiler to pick only
the relevant settings, at build time.

The relevant DRAM chips/board specific configuration parameters are
delivered via Kconfig, so this code here should work for all supported
SoCs and DRAM chips combinations.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Sam Edwards <CFSworks@gmail.com>
---
 drivers/Makefile                   |    1 +
 drivers/ram/Makefile               |    3 +
 drivers/ram/sunxi/Kconfig          |   59 ++
 drivers/ram/sunxi/Makefile         |    4 +
 drivers/ram/sunxi/dram_sun20i_d1.c | 1432 ++++++++++++++++++++++++++++
 drivers/ram/sunxi/dram_sun20i_d1.h |   73 ++
 6 files changed, 1572 insertions(+)
 create mode 100644 drivers/ram/sunxi/Makefile
 create mode 100644 drivers/ram/sunxi/dram_sun20i_d1.c
 create mode 100644 drivers/ram/sunxi/dram_sun20i_d1.h

Comments

Samuel Holland Oct. 22, 2023, 3:52 a.m. UTC | #1
Hi Andre,

On 9/28/23 16:54, Andre Przywara wrote:
> The Allwinner R528/T113-s/D1/D1s SoCs all share the same die, so use the
> same DRAM initialisation code.
> Make use of prior art here and lift some code from awboot[1], which
> carried init code based on earlier decompilation efforts, but with a
> GPL2 license tag.
> This code has been heavily reworked and cleaned up, to match previous
> DRAM routines for other SoCs, and also to be closer to U-Boot's coding
> style and support routines.
> The actual DRAM chip timing parameters are included in the main file,
> since they cover all DRAM types, and are protected by a new Kconfig
> CONFIG_SUNXI_DRAM_TYPE symbol, which allows the compiler to pick only
> the relevant settings, at build time.
> 
> The relevant DRAM chips/board specific configuration parameters are
> delivered via Kconfig, so this code here should work for all supported
> SoCs and DRAM chips combinations.
> 
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> Tested-by: Sam Edwards <CFSworks@gmail.com>
> ---
>  drivers/Makefile                   |    1 +
>  drivers/ram/Makefile               |    3 +
>  drivers/ram/sunxi/Kconfig          |   59 ++
>  drivers/ram/sunxi/Makefile         |    4 +
>  drivers/ram/sunxi/dram_sun20i_d1.c | 1432 ++++++++++++++++++++++++++++
>  drivers/ram/sunxi/dram_sun20i_d1.h |   73 ++
>  6 files changed, 1572 insertions(+)
>  create mode 100644 drivers/ram/sunxi/Makefile
>  create mode 100644 drivers/ram/sunxi/dram_sun20i_d1.c
>  create mode 100644 drivers/ram/sunxi/dram_sun20i_d1.h
> 
> diff --git a/drivers/Makefile b/drivers/Makefile
> index efc2a4afb24..5a4bedf7305 100644
> --- a/drivers/Makefile
> +++ b/drivers/Makefile
> @@ -56,6 +56,7 @@ obj-$(CONFIG_$(SPL_)ALTERA_SDRAM) += ddr/altera/
>  obj-$(CONFIG_ARCH_IMX8M) += ddr/imx/imx8m/
>  obj-$(CONFIG_IMX8ULP_DRAM) += ddr/imx/imx8ulp/
>  obj-$(CONFIG_ARCH_IMX9) += ddr/imx/imx9/
> +obj-$(CONFIG_DRAM_SUN8I_R528) += ram/

This would need to be duplicated for DRAM_SUN20I_D1.

>  obj-$(CONFIG_SPL_DM_RESET) += reset/
>  obj-$(CONFIG_SPL_MUSB_NEW) += usb/musb-new/
>  obj-$(CONFIG_SPL_USB_GADGET) += usb/gadget/
> diff --git a/drivers/ram/Makefile b/drivers/ram/Makefile
> index 6eb1a241359..b4750ea11c4 100644
> --- a/drivers/ram/Makefile
> +++ b/drivers/ram/Makefile
> @@ -23,6 +23,9 @@ obj-$(CONFIG_RAM_SIFIVE) += sifive/
>  ifdef CONFIG_SPL_BUILD
>  obj-$(CONFIG_SPL_STARFIVE_DDR) += starfive/
>  endif
> +
> +obj-$(CONFIG_DRAM_SUN8I_R528) += sunxi/

This would need to be duplicated for DRAM_SUN20I_D1.

> +
>  obj-$(CONFIG_ARCH_OCTEON) += octeon/
>  
>  obj-$(CONFIG_ARCH_RMOBILE) += renesas/
> diff --git a/drivers/ram/sunxi/Kconfig b/drivers/ram/sunxi/Kconfig
> index 261d7f57409..35eeda58efa 100644
> --- a/drivers/ram/sunxi/Kconfig
> +++ b/drivers/ram/sunxi/Kconfig
> @@ -12,3 +12,62 @@ config DRAM_SUN8I_R528
>  	default y if MACH_SUN8I_R528
>  	help
>  	  Select this DRAM controller driver for the R528/T113s SoCs.
> +
> +if DRAM_SUN20I_D1 || DRAM_SUN8I_R528
> +
> +config DRAM_SUNXI_ODT_EN

You have a mixture of "DRAM_SUNXI" and "SUNXI_DRAM" for the tunables
here. I would recommend being consistent.

> +	hex "DRAM ODT EN parameter"
> +	default 0x1
> +	help
> +	  ODT EN value from vendor DRAM settings.
> +
> +config DRAM_SUNXI_TPR0
> +	hex "DRAM TPR0 parameter"
> +	default 0x0
> +	help
> +	  TPR0 value from vendor DRAM settings.
> +
> +config DRAM_SUNXI_TPR11
> +	hex "DRAM TPR11 parameter"
> +	default 0x0
> +	help
> +	  TPR11 value from vendor DRAM settings.
> +
> +config DRAM_SUNXI_TPR12
> +	hex "DRAM TPR12 parameter"
> +	default 0x0
> +	help
> +	  TPR12 value from vendor DRAM settings.
> +
> +config DRAM_SUNXI_TPR13
> +	hex "DRAM TPR13 parameter"
> +	default 0x0

I would suggest dropping the defaults for these tunables. It was
non-obvious that I was missing some configuration when I switched to
your driver. I think it's reasonable to require the defconfig/user to
provide these.

> +	help
> +	  TPR13 value from vendor DRAM settings. It tells which features
> +	  should be configured.
> +
> +choice
> +	prompt "DRAM chip type"
> +	default SUNXI_DRAM_TYPE_DDR3 if DRAM_SUN8I_R528 || DRAM_SUN20I_D1
> +
> +config SUNXI_DRAM_TYPE_DDR2
> +        bool "DDR2 chips"
> +
> +config SUNXI_DRAM_TYPE_DDR3
> +        bool "DDR3 chips"
> +
> +config SUNXI_DRAM_TYPE_LPDDR2
> +        bool "LPDDR2 chips"
> +
> +config SUNXI_DRAM_TYPE_LPDDR3
> +        bool "LPDDR3 chips"
> +endchoice
> +
> +config SUNXI_DRAM_TYPE
> +	int
> +	default 2 if SUNXI_DRAM_TYPE_DDR2
> +	default 3 if SUNXI_DRAM_TYPE_DDR3
> +	default 6 if SUNXI_DRAM_TYPE_LPDDR2
> +	default 7 if SUNXI_DRAM_TYPE_LPDDR3
> +
> +endif
> diff --git a/drivers/ram/sunxi/Makefile b/drivers/ram/sunxi/Makefile
> new file mode 100644
> index 00000000000..d6fb2cf0b65
> --- /dev/null
> +++ b/drivers/ram/sunxi/Makefile
> @@ -0,0 +1,4 @@
> +# SPDX-License-Identifier: GPL-2.0+
> +
> +obj-$(CONFIG_DRAM_SUN20I_D1) += dram_sun20i_d1.o
> +obj-$(CONFIG_DRAM_SUN8I_R528) += dram_sun20i_d1.o
> diff --git a/drivers/ram/sunxi/dram_sun20i_d1.c b/drivers/ram/sunxi/dram_sun20i_d1.c
> new file mode 100644
> index 00000000000..c766fc24065
> --- /dev/null
> +++ b/drivers/ram/sunxi/dram_sun20i_d1.c
> @@ -0,0 +1,1432 @@
> [...]
> +/*
> + * This routine sizes a DRAM device by cycling through address lines and
> + * figuring out if they are connected to a real address line, or if the
> + * address is a mirror.
> + * First the column and bank bit allocations are set to low values (2 and 9
> + * address lines). Then a maximum allocation (16 lines) is set for rows and
> + * this is tested.
> + * Next the BA2 line is checked. This seems to be placed above the column,
> + * BA0-1 and row addresses. Finally, the column address is allocated 13 lines
> + * and these are tested. The results are placed in dram_para1 and dram_para2.
> + */
> +static int auto_scan_dram_size(const dram_para_t *para, dram_config_t *config)
> +{
> +	unsigned int rval, i, j, rank, maxrank, offs;
> +	unsigned int shft;
> +	unsigned long ptr, mc_work_mode, chk;

This breaks on 64-bit architectures, because readl(chk) can never equal
~ptr. Please change ptr and chk to unsigned int.

> +
> +	if (mctl_core_init(para, config) == 0) {
> +		printf("DRAM initialisation error : 0\n");
> +		return 0;
> +	}
> +
> +	maxrank	= (config->dram_para2 & 0xf000) ? 2 : 1;
> +	mc_work_mode = 0x3102000;
> +	offs = 0;
> +
> +	/* write test pattern */
> +	for (i = 0, ptr = CFG_SYS_SDRAM_BASE; i < 64; i++, ptr += 4)
> +		writel((i & 0x1) ? ptr : ~ptr, ptr);
> +
> +	for (rank = 0; rank < maxrank;) {
> +		/* set row mode */
> +		clrsetbits_le32(mc_work_mode, 0xf0c, 0x6f0);
> +		udelay(1);
> +
> +		// Scan per address line, until address wraps (i.e. see shadow)
> +		for (i = 11; i < 17; i++) {
> +			chk = CFG_SYS_SDRAM_BASE + (1U << (i + 11));
> +			ptr = CFG_SYS_SDRAM_BASE;
> +			for (j = 0; j < 64; j++) {
> +				if (readl(chk) != ((j & 1) ? ptr : ~ptr))
> +					break;
> +				ptr += 4;
> +				chk += 4;
> +			}
> +			if (j == 64)
> +				break;
> +		}
> +		if (i > 16)
> +			i = 16;
> +		debug("rank %d row = %d\n", rank, i);
> +
> +		/* Store rows in para 1 */
> +		shft = offs + 4;
> +		rval = config->dram_para1;
> +		rval &= ~(0xff << shft);
> +		rval |= i << shft;
> +		config->dram_para1 = rval;
> +
> +		if (rank == 1)		/* Set bank mode for rank0 */
> +			clrsetbits_le32(0x3102000, 0xffc, 0x6a4);
> +
> +		/* Set bank mode for current rank */
> +		clrsetbits_le32(mc_work_mode, 0xffc, 0x6a4);
> +		udelay(1);
> +
> +		// Test if bit A23 is BA2 or mirror XXX A22?
> +		chk = CFG_SYS_SDRAM_BASE + (1U << 22);
> +		ptr = CFG_SYS_SDRAM_BASE;
> +		for (i = 0, j = 0; i < 64; i++) {
> +			if (readl(chk) != ((i & 1) ? ptr : ~ptr)) {
> +				j = 1;
> +				break;
> +			}
> +			ptr += 4;
> +			chk += 4;
> +		}
> +
> +		debug("rank %d bank = %d\n", rank, (j + 1) << 2); /* 4 or 8 */
> +
> +		/* Store banks in para 1 */
> +		shft = 12 + offs;
> +		rval = config->dram_para1;
> +		rval &= ~(0xf << shft);
> +		rval |= j << shft;
> +		config->dram_para1 = rval;
> +
> +		if (rank == 1)		/* Set page mode for rank0 */
> +			clrsetbits_le32(0x3102000, 0xffc, 0xaa0);
> +
> +		/* Set page mode for current rank */
> +		clrsetbits_le32(mc_work_mode, 0xffc, 0xaa0);
> +		udelay(1);
> +
> +		// Scan per address line, until address wraps (i.e. see shadow)
> +		for (i = 9; i < 14; i++) {
> +			chk = CFG_SYS_SDRAM_BASE + (1U << i);
> +			ptr = CFG_SYS_SDRAM_BASE;
> +			for (j = 0; j < 64; j++) {
> +				if (readl(chk) != ((j & 1) ? ptr : ~ptr))
> +					break;
> +				ptr += 4;
> +				chk += 4;
> +			}
> +			if (j == 64)
> +				break;
> +		}
> +		if (i > 13)
> +			i = 13;
> +
> +		unsigned int pgsize = (i == 9) ? 0 : (1 << (i - 10));
> +		debug("rank %d page size = %d KB\n", rank, pgsize);
> +
> +		/* Store page size */
> +		shft = offs;
> +		rval = config->dram_para1;
> +		rval &= ~(0xf << shft);
> +		rval |= pgsize << shft;
> +		config->dram_para1 = rval;
> +
> +		// Move to next rank
> +		rank++;
> +		if (rank != maxrank) {
> +			if (rank == 1) {
> +				/* MC_WORK_MODE */
> +				clrsetbits_le32(0x3202000, 0xffc, 0x6f0);
> +
> +				/* MC_WORK_MODE2 */
> +				clrsetbits_le32(0x3202004, 0xffc, 0x6f0);
> +			}
> +			/* store rank1 config in upper half of para1 */
> +			offs += 16;
> +			mc_work_mode += 4;	/* move to MC_WORK_MODE2 */
> +		}
> +	}
> +	if (maxrank == 2) {
> +		config->dram_para2 &= 0xfffff0ff;
> +		/* note: rval is equal to para->dram_para1 here */
> +		if ((rval & 0xffff) == (rval >> 16)) {
> +			debug("rank1 config same as rank0\n");
> +		} else {
> +			config->dram_para2 |= BIT(8);
> +			debug("rank1 config different from rank0\n");
> +		}
> +	}
> +
> +	return 1;
> +}
> [...]
> +static int sunxi_ram_probe(struct udevice *dev)
> +{
> +	struct sunxi_ram_priv *priv = dev_get_priv(dev);
> +	unsigned long dram_size;
> +
> +	debug("%s: %s: probing\n", __func__, dev->name);
> +
> +	dram_size = sunxi_dram_init();
> +	if (!dram_size) {
> +		printf("DRAM init failed: %d\n", ret);

There is no ret variable anymore, so this fails to compile. With this
line and the variable size issue fixed, this driver works on my Nezha
board, so with those fixes:

Tested-by: Samuel Holland <samuel@sholland.org>

> +		return -ENODEV;
> +	}
> +
> +	priv->size = dram_size;
> +
> +	return 0;
> +}
Andre Przywara Oct. 22, 2023, 10:40 p.m. UTC | #2
On Sat, 21 Oct 2023 22:52:06 -0500
Samuel Holland <samuel@sholland.org> wrote:

Hi Samuel,

> On 9/28/23 16:54, Andre Przywara wrote:
> > The Allwinner R528/T113-s/D1/D1s SoCs all share the same die, so use the
> > same DRAM initialisation code.
> > Make use of prior art here and lift some code from awboot[1], which
> > carried init code based on earlier decompilation efforts, but with a
> > GPL2 license tag.
> > This code has been heavily reworked and cleaned up, to match previous
> > DRAM routines for other SoCs, and also to be closer to U-Boot's coding
> > style and support routines.
> > The actual DRAM chip timing parameters are included in the main file,
> > since they cover all DRAM types, and are protected by a new Kconfig
> > CONFIG_SUNXI_DRAM_TYPE symbol, which allows the compiler to pick only
> > the relevant settings, at build time.
> > 
> > The relevant DRAM chips/board specific configuration parameters are
> > delivered via Kconfig, so this code here should work for all supported
> > SoCs and DRAM chips combinations.
> > 
> > Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> > Tested-by: Sam Edwards <CFSworks@gmail.com>
> > ---
> >  drivers/Makefile                   |    1 +
> >  drivers/ram/Makefile               |    3 +
> >  drivers/ram/sunxi/Kconfig          |   59 ++
> >  drivers/ram/sunxi/Makefile         |    4 +
> >  drivers/ram/sunxi/dram_sun20i_d1.c | 1432 ++++++++++++++++++++++++++++
> >  drivers/ram/sunxi/dram_sun20i_d1.h |   73 ++
> >  6 files changed, 1572 insertions(+)
> >  create mode 100644 drivers/ram/sunxi/Makefile
> >  create mode 100644 drivers/ram/sunxi/dram_sun20i_d1.c
> >  create mode 100644 drivers/ram/sunxi/dram_sun20i_d1.h
> > 
> > diff --git a/drivers/Makefile b/drivers/Makefile
> > index efc2a4afb24..5a4bedf7305 100644
> > --- a/drivers/Makefile
> > +++ b/drivers/Makefile
> > @@ -56,6 +56,7 @@ obj-$(CONFIG_$(SPL_)ALTERA_SDRAM) += ddr/altera/
> >  obj-$(CONFIG_ARCH_IMX8M) += ddr/imx/imx8m/
> >  obj-$(CONFIG_IMX8ULP_DRAM) += ddr/imx/imx8ulp/
> >  obj-$(CONFIG_ARCH_IMX9) += ddr/imx/imx9/
> > +obj-$(CONFIG_DRAM_SUN8I_R528) += ram/  
> 
> This would need to be duplicated for DRAM_SUN20I_D1.
> 
> >  obj-$(CONFIG_SPL_DM_RESET) += reset/
> >  obj-$(CONFIG_SPL_MUSB_NEW) += usb/musb-new/
> >  obj-$(CONFIG_SPL_USB_GADGET) += usb/gadget/
> > diff --git a/drivers/ram/Makefile b/drivers/ram/Makefile
> > index 6eb1a241359..b4750ea11c4 100644
> > --- a/drivers/ram/Makefile
> > +++ b/drivers/ram/Makefile
> > @@ -23,6 +23,9 @@ obj-$(CONFIG_RAM_SIFIVE) += sifive/
> >  ifdef CONFIG_SPL_BUILD
> >  obj-$(CONFIG_SPL_STARFIVE_DDR) += starfive/
> >  endif
> > +
> > +obj-$(CONFIG_DRAM_SUN8I_R528) += sunxi/  
> 
> This would need to be duplicated for DRAM_SUN20I_D1.

Right, so I joined both symbols into one now. I think I wanted to keep
the DM_RAM and non-DM parts logically apart, but it works nevertheless.

My gut feeling is this needs more adjustments anyway once we need the
DM_RAM or want to extend it to more SoCs, so we can fix things when
they need fixing, later.

> 
> > +
> >  obj-$(CONFIG_ARCH_OCTEON) += octeon/
> >  
> >  obj-$(CONFIG_ARCH_RMOBILE) += renesas/
> > diff --git a/drivers/ram/sunxi/Kconfig b/drivers/ram/sunxi/Kconfig
> > index 261d7f57409..35eeda58efa 100644
> > --- a/drivers/ram/sunxi/Kconfig
> > +++ b/drivers/ram/sunxi/Kconfig
> > @@ -12,3 +12,62 @@ config DRAM_SUN8I_R528
> >  	default y if MACH_SUN8I_R528
> >  	help
> >  	  Select this DRAM controller driver for the R528/T113s SoCs.
> > +
> > +if DRAM_SUN20I_D1 || DRAM_SUN8I_R528
> > +
> > +config DRAM_SUNXI_ODT_EN  
> 
> You have a mixture of "DRAM_SUNXI" and "SUNXI_DRAM" for the tunables
> here. I would recommend being consistent.

This was chosen to stay consistent with the existing DRAM drivers,
which use DRAM_SUNxx_ for parameters, but SUNXI_DRAM_TYPE_ for the type
selection. I was looking into moving the other Allwinner DRAM drivers
into here as well (at least for every future SoC), and tested this with
the H616: keeping the symbols compatible was a requirement.

> 
> > +	hex "DRAM ODT EN parameter"
> > +	default 0x1
> > +	help
> > +	  ODT EN value from vendor DRAM settings.
> > +
> > +config DRAM_SUNXI_TPR0
> > +	hex "DRAM TPR0 parameter"
> > +	default 0x0
> > +	help
> > +	  TPR0 value from vendor DRAM settings.
> > +
> > +config DRAM_SUNXI_TPR11
> > +	hex "DRAM TPR11 parameter"
> > +	default 0x0
> > +	help
> > +	  TPR11 value from vendor DRAM settings.
> > +
> > +config DRAM_SUNXI_TPR12
> > +	hex "DRAM TPR12 parameter"
> > +	default 0x0
> > +	help
> > +	  TPR12 value from vendor DRAM settings.
> > +
> > +config DRAM_SUNXI_TPR13
> > +	hex "DRAM TPR13 parameter"
> > +	default 0x0  
> 
> I would suggest dropping the defaults for these tunables. It was
> non-obvious that I was missing some configuration when I switched to
> your driver. I think it's reasonable to require the defconfig/user to
> provide these.

Yeah, that's a good point. No actual value is 0, so this doesn't even
simplify defconfigs.

> > +	help
> > +	  TPR13 value from vendor DRAM settings. It tells which features
> > +	  should be configured.
> > +
> > +choice
> > +	prompt "DRAM chip type"
> > +	default SUNXI_DRAM_TYPE_DDR3 if DRAM_SUN8I_R528 || DRAM_SUN20I_D1
> > +
> > +config SUNXI_DRAM_TYPE_DDR2
> > +        bool "DDR2 chips"
> > +
> > +config SUNXI_DRAM_TYPE_DDR3
> > +        bool "DDR3 chips"
> > +
> > +config SUNXI_DRAM_TYPE_LPDDR2
> > +        bool "LPDDR2 chips"
> > +
> > +config SUNXI_DRAM_TYPE_LPDDR3
> > +        bool "LPDDR3 chips"
> > +endchoice
> > +
> > +config SUNXI_DRAM_TYPE
> > +	int
> > +	default 2 if SUNXI_DRAM_TYPE_DDR2
> > +	default 3 if SUNXI_DRAM_TYPE_DDR3
> > +	default 6 if SUNXI_DRAM_TYPE_LPDDR2
> > +	default 7 if SUNXI_DRAM_TYPE_LPDDR3
> > +
> > +endif
> > diff --git a/drivers/ram/sunxi/Makefile b/drivers/ram/sunxi/Makefile
> > new file mode 100644
> > index 00000000000..d6fb2cf0b65
> > --- /dev/null
> > +++ b/drivers/ram/sunxi/Makefile
> > @@ -0,0 +1,4 @@
> > +# SPDX-License-Identifier: GPL-2.0+
> > +
> > +obj-$(CONFIG_DRAM_SUN20I_D1) += dram_sun20i_d1.o
> > +obj-$(CONFIG_DRAM_SUN8I_R528) += dram_sun20i_d1.o
> > diff --git a/drivers/ram/sunxi/dram_sun20i_d1.c b/drivers/ram/sunxi/dram_sun20i_d1.c
> > new file mode 100644
> > index 00000000000..c766fc24065
> > --- /dev/null
> > +++ b/drivers/ram/sunxi/dram_sun20i_d1.c
> > @@ -0,0 +1,1432 @@
> > [...]
> > +/*
> > + * This routine sizes a DRAM device by cycling through address lines and
> > + * figuring out if they are connected to a real address line, or if the
> > + * address is a mirror.
> > + * First the column and bank bit allocations are set to low values (2 and 9
> > + * address lines). Then a maximum allocation (16 lines) is set for rows and
> > + * this is tested.
> > + * Next the BA2 line is checked. This seems to be placed above the column,
> > + * BA0-1 and row addresses. Finally, the column address is allocated 13 lines
> > + * and these are tested. The results are placed in dram_para1 and dram_para2.
> > + */
> > +static int auto_scan_dram_size(const dram_para_t *para, dram_config_t *config)
> > +{
> > +	unsigned int rval, i, j, rank, maxrank, offs;
> > +	unsigned int shft;
> > +	unsigned long ptr, mc_work_mode, chk;  
> 
> This breaks on 64-bit architectures, because readl(chk) can never equal
> ~ptr. Please change ptr and chk to unsigned int.

I think they were originally ints (at least I see it like this is an
earlier version), but I changed it to make "ptr" a pointer compatible
type.
Definitely "chk" is only used as a pointer, so should be long (or
uintptr_t).
The actual problem is that "ptr" is used both as a pointer *and* a
payload, which is odd. I will keep ptr long, but make sure to
write only a true 32 bit payload into the address it points to.

> 
> > +
> > +	if (mctl_core_init(para, config) == 0) {
> > +		printf("DRAM initialisation error : 0\n");
> > +		return 0;
> > +	}
> > +
> > +	maxrank	= (config->dram_para2 & 0xf000) ? 2 : 1;
> > +	mc_work_mode = 0x3102000;
> > +	offs = 0;
> > +
> > +	/* write test pattern */
> > +	for (i = 0, ptr = CFG_SYS_SDRAM_BASE; i < 64; i++, ptr += 4)
> > +		writel((i & 0x1) ? ptr : ~ptr, ptr);
> > +
> > +	for (rank = 0; rank < maxrank;) {
> > +		/* set row mode */
> > +		clrsetbits_le32(mc_work_mode, 0xf0c, 0x6f0);
> > +		udelay(1);
> > +
> > +		// Scan per address line, until address wraps (i.e. see shadow)
> > +		for (i = 11; i < 17; i++) {
> > +			chk = CFG_SYS_SDRAM_BASE + (1U << (i + 11));
> > +			ptr = CFG_SYS_SDRAM_BASE;
> > +			for (j = 0; j < 64; j++) {
> > +				if (readl(chk) != ((j & 1) ? ptr : ~ptr))
> > +					break;
> > +				ptr += 4;
> > +				chk += 4;
> > +			}
> > +			if (j == 64)
> > +				break;
> > +		}
> > +		if (i > 16)
> > +			i = 16;
> > +		debug("rank %d row = %d\n", rank, i);
> > +
> > +		/* Store rows in para 1 */
> > +		shft = offs + 4;
> > +		rval = config->dram_para1;
> > +		rval &= ~(0xff << shft);
> > +		rval |= i << shft;
> > +		config->dram_para1 = rval;
> > +
> > +		if (rank == 1)		/* Set bank mode for rank0 */
> > +			clrsetbits_le32(0x3102000, 0xffc, 0x6a4);
> > +
> > +		/* Set bank mode for current rank */
> > +		clrsetbits_le32(mc_work_mode, 0xffc, 0x6a4);
> > +		udelay(1);
> > +
> > +		// Test if bit A23 is BA2 or mirror XXX A22?
> > +		chk = CFG_SYS_SDRAM_BASE + (1U << 22);
> > +		ptr = CFG_SYS_SDRAM_BASE;
> > +		for (i = 0, j = 0; i < 64; i++) {
> > +			if (readl(chk) != ((i & 1) ? ptr : ~ptr)) {
> > +				j = 1;
> > +				break;
> > +			}
> > +			ptr += 4;
> > +			chk += 4;
> > +		}
> > +
> > +		debug("rank %d bank = %d\n", rank, (j + 1) << 2); /* 4 or 8 */
> > +
> > +		/* Store banks in para 1 */
> > +		shft = 12 + offs;
> > +		rval = config->dram_para1;
> > +		rval &= ~(0xf << shft);
> > +		rval |= j << shft;
> > +		config->dram_para1 = rval;
> > +
> > +		if (rank == 1)		/* Set page mode for rank0 */
> > +			clrsetbits_le32(0x3102000, 0xffc, 0xaa0);
> > +
> > +		/* Set page mode for current rank */
> > +		clrsetbits_le32(mc_work_mode, 0xffc, 0xaa0);
> > +		udelay(1);
> > +
> > +		// Scan per address line, until address wraps (i.e. see shadow)
> > +		for (i = 9; i < 14; i++) {
> > +			chk = CFG_SYS_SDRAM_BASE + (1U << i);
> > +			ptr = CFG_SYS_SDRAM_BASE;
> > +			for (j = 0; j < 64; j++) {
> > +				if (readl(chk) != ((j & 1) ? ptr : ~ptr))
> > +					break;
> > +				ptr += 4;
> > +				chk += 4;
> > +			}
> > +			if (j == 64)
> > +				break;
> > +		}
> > +		if (i > 13)
> > +			i = 13;
> > +
> > +		unsigned int pgsize = (i == 9) ? 0 : (1 << (i - 10));
> > +		debug("rank %d page size = %d KB\n", rank, pgsize);
> > +
> > +		/* Store page size */
> > +		shft = offs;
> > +		rval = config->dram_para1;
> > +		rval &= ~(0xf << shft);
> > +		rval |= pgsize << shft;
> > +		config->dram_para1 = rval;
> > +
> > +		// Move to next rank
> > +		rank++;
> > +		if (rank != maxrank) {
> > +			if (rank == 1) {
> > +				/* MC_WORK_MODE */
> > +				clrsetbits_le32(0x3202000, 0xffc, 0x6f0);
> > +
> > +				/* MC_WORK_MODE2 */
> > +				clrsetbits_le32(0x3202004, 0xffc, 0x6f0);
> > +			}
> > +			/* store rank1 config in upper half of para1 */
> > +			offs += 16;
> > +			mc_work_mode += 4;	/* move to MC_WORK_MODE2 */
> > +		}
> > +	}
> > +	if (maxrank == 2) {
> > +		config->dram_para2 &= 0xfffff0ff;
> > +		/* note: rval is equal to para->dram_para1 here */
> > +		if ((rval & 0xffff) == (rval >> 16)) {
> > +			debug("rank1 config same as rank0\n");
> > +		} else {
> > +			config->dram_para2 |= BIT(8);
> > +			debug("rank1 config different from rank0\n");
> > +		}
> > +	}
> > +
> > +	return 1;
> > +}
> > [...]
> > +static int sunxi_ram_probe(struct udevice *dev)
> > +{
> > +	struct sunxi_ram_priv *priv = dev_get_priv(dev);
> > +	unsigned long dram_size;
> > +
> > +	debug("%s: %s: probing\n", __func__, dev->name);
> > +
> > +	dram_size = sunxi_dram_init();
> > +	if (!dram_size) {
> > +		printf("DRAM init failed: %d\n", ret);  
> 
> There is no ret variable anymore, so this fails to compile. With this
> line and the variable size issue fixed, this driver works on my Nezha
> board, so with those fixes:

Ah, right, thanks for the heads up. I think I had some trick to compile
test this code once, but didn't use it since last year.

> Tested-by: Samuel Holland <samuel@sholland.org>

Thanks!
Andre

P.S. This driver has a lot of rough edges anyway (the whole
clock/"system" setup side, for a start), but we should get things
moving now, before the RFC version celebrates its first birthday. So I
will merge it, but am happy to take fixes: either cleanups, or fixes
for the D1.

> > +		return -ENODEV;
> > +	}
> > +
> > +	priv->size = dram_size;
> > +
> > +	return 0;
> > +}  
>
Samuel Holland Oct. 23, 2023, 2:58 a.m. UTC | #3
Hi Andre,

On 10/22/23 17:40, Andre Przywara wrote:
> On Sat, 21 Oct 2023 22:52:06 -0500
> Samuel Holland <samuel@sholland.org> wrote:
>> On 9/28/23 16:54, Andre Przywara wrote:
>>> The Allwinner R528/T113-s/D1/D1s SoCs all share the same die, so use the
>>> same DRAM initialisation code.
>>> Make use of prior art here and lift some code from awboot[1], which
>>> carried init code based on earlier decompilation efforts, but with a
>>> GPL2 license tag.
>>> This code has been heavily reworked and cleaned up, to match previous
>>> DRAM routines for other SoCs, and also to be closer to U-Boot's coding
>>> style and support routines.
>>> The actual DRAM chip timing parameters are included in the main file,
>>> since they cover all DRAM types, and are protected by a new Kconfig
>>> CONFIG_SUNXI_DRAM_TYPE symbol, which allows the compiler to pick only
>>> the relevant settings, at build time.
>>>
>>> The relevant DRAM chips/board specific configuration parameters are
>>> delivered via Kconfig, so this code here should work for all supported
>>> SoCs and DRAM chips combinations.
>>>
>>> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
>>> Tested-by: Sam Edwards <CFSworks@gmail.com>
>>> ---
>>>  drivers/Makefile                   |    1 +
>>>  drivers/ram/Makefile               |    3 +
>>>  drivers/ram/sunxi/Kconfig          |   59 ++
>>>  drivers/ram/sunxi/Makefile         |    4 +
>>>  drivers/ram/sunxi/dram_sun20i_d1.c | 1432 ++++++++++++++++++++++++++++
>>>  drivers/ram/sunxi/dram_sun20i_d1.h |   73 ++
>>>  6 files changed, 1572 insertions(+)
>>>  create mode 100644 drivers/ram/sunxi/Makefile
>>>  create mode 100644 drivers/ram/sunxi/dram_sun20i_d1.c
>>>  create mode 100644 drivers/ram/sunxi/dram_sun20i_d1.h
>>>
>>> diff --git a/drivers/Makefile b/drivers/Makefile
>>> index efc2a4afb24..5a4bedf7305 100644
>>> --- a/drivers/Makefile
>>> +++ b/drivers/Makefile
>>> @@ -56,6 +56,7 @@ obj-$(CONFIG_$(SPL_)ALTERA_SDRAM) += ddr/altera/
>>>  obj-$(CONFIG_ARCH_IMX8M) += ddr/imx/imx8m/
>>>  obj-$(CONFIG_IMX8ULP_DRAM) += ddr/imx/imx8ulp/
>>>  obj-$(CONFIG_ARCH_IMX9) += ddr/imx/imx9/
>>> +obj-$(CONFIG_DRAM_SUN8I_R528) += ram/  
>>
>> This would need to be duplicated for DRAM_SUN20I_D1.
>>
>>>  obj-$(CONFIG_SPL_DM_RESET) += reset/
>>>  obj-$(CONFIG_SPL_MUSB_NEW) += usb/musb-new/
>>>  obj-$(CONFIG_SPL_USB_GADGET) += usb/gadget/
>>> diff --git a/drivers/ram/Makefile b/drivers/ram/Makefile
>>> index 6eb1a241359..b4750ea11c4 100644
>>> --- a/drivers/ram/Makefile
>>> +++ b/drivers/ram/Makefile
>>> @@ -23,6 +23,9 @@ obj-$(CONFIG_RAM_SIFIVE) += sifive/
>>>  ifdef CONFIG_SPL_BUILD
>>>  obj-$(CONFIG_SPL_STARFIVE_DDR) += starfive/
>>>  endif
>>> +
>>> +obj-$(CONFIG_DRAM_SUN8I_R528) += sunxi/  
>>
>> This would need to be duplicated for DRAM_SUN20I_D1.
> 
> Right, so I joined both symbols into one now. I think I wanted to keep
> the DM_RAM and non-DM parts logically apart, but it works nevertheless.
> 
> My gut feeling is this needs more adjustments anyway once we need the
> DM_RAM or want to extend it to more SoCs, so we can fix things when
> they need fixing, later.
> 
>>
>>> +
>>>  obj-$(CONFIG_ARCH_OCTEON) += octeon/
>>>  
>>>  obj-$(CONFIG_ARCH_RMOBILE) += renesas/
>>> diff --git a/drivers/ram/sunxi/Kconfig b/drivers/ram/sunxi/Kconfig
>>> index 261d7f57409..35eeda58efa 100644
>>> --- a/drivers/ram/sunxi/Kconfig
>>> +++ b/drivers/ram/sunxi/Kconfig
>>> @@ -12,3 +12,62 @@ config DRAM_SUN8I_R528
>>>  	default y if MACH_SUN8I_R528
>>>  	help
>>>  	  Select this DRAM controller driver for the R528/T113s SoCs.
>>> +
>>> +if DRAM_SUN20I_D1 || DRAM_SUN8I_R528
>>> +
>>> +config DRAM_SUNXI_ODT_EN  
>>
>> You have a mixture of "DRAM_SUNXI" and "SUNXI_DRAM" for the tunables
>> here. I would recommend being consistent.
> 
> This was chosen to stay consistent with the existing DRAM drivers,
> which use DRAM_SUNxx_ for parameters, but SUNXI_DRAM_TYPE_ for the type
> selection. I was looking into moving the other Allwinner DRAM drivers
> into here as well (at least for every future SoC), and tested this with
> the H616: keeping the symbols compatible was a requirement.

Okay, that's fair. We can always revisit this later.

>>> +	hex "DRAM ODT EN parameter"
>>> +	default 0x1
>>> +	help
>>> +	  ODT EN value from vendor DRAM settings.
>>> +
>>> +config DRAM_SUNXI_TPR0
>>> +	hex "DRAM TPR0 parameter"
>>> +	default 0x0
>>> +	help
>>> +	  TPR0 value from vendor DRAM settings.
>>> +
>>> +config DRAM_SUNXI_TPR11
>>> +	hex "DRAM TPR11 parameter"
>>> +	default 0x0
>>> +	help
>>> +	  TPR11 value from vendor DRAM settings.
>>> +
>>> +config DRAM_SUNXI_TPR12
>>> +	hex "DRAM TPR12 parameter"
>>> +	default 0x0
>>> +	help
>>> +	  TPR12 value from vendor DRAM settings.
>>> +
>>> +config DRAM_SUNXI_TPR13
>>> +	hex "DRAM TPR13 parameter"
>>> +	default 0x0  
>>
>> I would suggest dropping the defaults for these tunables. It was
>> non-obvious that I was missing some configuration when I switched to
>> your driver. I think it's reasonable to require the defconfig/user to
>> provide these.
> 
> Yeah, that's a good point. No actual value is 0, so this doesn't even
> simplify defconfigs.
> 
>>> +	help
>>> +	  TPR13 value from vendor DRAM settings. It tells which features
>>> +	  should be configured.
>>> +
>>> +choice
>>> +	prompt "DRAM chip type"
>>> +	default SUNXI_DRAM_TYPE_DDR3 if DRAM_SUN8I_R528 || DRAM_SUN20I_D1
>>> +
>>> +config SUNXI_DRAM_TYPE_DDR2
>>> +        bool "DDR2 chips"
>>> +
>>> +config SUNXI_DRAM_TYPE_DDR3
>>> +        bool "DDR3 chips"
>>> +
>>> +config SUNXI_DRAM_TYPE_LPDDR2
>>> +        bool "LPDDR2 chips"
>>> +
>>> +config SUNXI_DRAM_TYPE_LPDDR3
>>> +        bool "LPDDR3 chips"
>>> +endchoice
>>> +
>>> +config SUNXI_DRAM_TYPE
>>> +	int
>>> +	default 2 if SUNXI_DRAM_TYPE_DDR2
>>> +	default 3 if SUNXI_DRAM_TYPE_DDR3
>>> +	default 6 if SUNXI_DRAM_TYPE_LPDDR2
>>> +	default 7 if SUNXI_DRAM_TYPE_LPDDR3
>>> +
>>> +endif
>>> diff --git a/drivers/ram/sunxi/Makefile b/drivers/ram/sunxi/Makefile
>>> new file mode 100644
>>> index 00000000000..d6fb2cf0b65
>>> --- /dev/null
>>> +++ b/drivers/ram/sunxi/Makefile
>>> @@ -0,0 +1,4 @@
>>> +# SPDX-License-Identifier: GPL-2.0+
>>> +
>>> +obj-$(CONFIG_DRAM_SUN20I_D1) += dram_sun20i_d1.o
>>> +obj-$(CONFIG_DRAM_SUN8I_R528) += dram_sun20i_d1.o
>>> diff --git a/drivers/ram/sunxi/dram_sun20i_d1.c b/drivers/ram/sunxi/dram_sun20i_d1.c
>>> new file mode 100644
>>> index 00000000000..c766fc24065
>>> --- /dev/null
>>> +++ b/drivers/ram/sunxi/dram_sun20i_d1.c
>>> @@ -0,0 +1,1432 @@
>>> [...]
>>> +/*
>>> + * This routine sizes a DRAM device by cycling through address lines and
>>> + * figuring out if they are connected to a real address line, or if the
>>> + * address is a mirror.
>>> + * First the column and bank bit allocations are set to low values (2 and 9
>>> + * address lines). Then a maximum allocation (16 lines) is set for rows and
>>> + * this is tested.
>>> + * Next the BA2 line is checked. This seems to be placed above the column,
>>> + * BA0-1 and row addresses. Finally, the column address is allocated 13 lines
>>> + * and these are tested. The results are placed in dram_para1 and dram_para2.
>>> + */
>>> +static int auto_scan_dram_size(const dram_para_t *para, dram_config_t *config)
>>> +{
>>> +	unsigned int rval, i, j, rank, maxrank, offs;
>>> +	unsigned int shft;
>>> +	unsigned long ptr, mc_work_mode, chk;  
>>
>> This breaks on 64-bit architectures, because readl(chk) can never equal
>> ~ptr. Please change ptr and chk to unsigned int.
> 
> I think they were originally ints (at least I see it like this is an
> earlier version), but I changed it to make "ptr" a pointer compatible
> type.
> Definitely "chk" is only used as a pointer, so should be long (or
> uintptr_t).
> The actual problem is that "ptr" is used both as a pointer *and* a
> payload, which is odd. I will keep ptr long, but make sure to
> write only a true 32 bit payload into the address it points to.

The problem isn't in the writing, it's in the "~ptr" expression in the
if statement -- readl(chk) will always have zero in its high 32 bits,
while ~ptr will set the high 32 bits. So a cast after the inversion
would also fix the problem.

>>> +
>>> +	if (mctl_core_init(para, config) == 0) {
>>> +		printf("DRAM initialisation error : 0\n");
>>> +		return 0;
>>> +	}
>>> +
>>> +	maxrank	= (config->dram_para2 & 0xf000) ? 2 : 1;
>>> +	mc_work_mode = 0x3102000;
>>> +	offs = 0;
>>> +
>>> +	/* write test pattern */
>>> +	for (i = 0, ptr = CFG_SYS_SDRAM_BASE; i < 64; i++, ptr += 4)
>>> +		writel((i & 0x1) ? ptr : ~ptr, ptr);
>>> +
>>> +	for (rank = 0; rank < maxrank;) {
>>> +		/* set row mode */
>>> +		clrsetbits_le32(mc_work_mode, 0xf0c, 0x6f0);
>>> +		udelay(1);
>>> +
>>> +		// Scan per address line, until address wraps (i.e. see shadow)
>>> +		for (i = 11; i < 17; i++) {
>>> +			chk = CFG_SYS_SDRAM_BASE + (1U << (i + 11));
>>> +			ptr = CFG_SYS_SDRAM_BASE;
>>> +			for (j = 0; j < 64; j++) {
>>> +				if (readl(chk) != ((j & 1) ? ptr : ~ptr))
>>> +					break;
>>> +				ptr += 4;
>>> +				chk += 4;
>>> +			}
>>> +			if (j == 64)
>>> +				break;
>>> +		}
>>> +		if (i > 16)
>>> +			i = 16;
>>> +		debug("rank %d row = %d\n", rank, i);
>>> +
>>> +		/* Store rows in para 1 */
>>> +		shft = offs + 4;
>>> +		rval = config->dram_para1;
>>> +		rval &= ~(0xff << shft);
>>> +		rval |= i << shft;
>>> +		config->dram_para1 = rval;
>>> +
>>> +		if (rank == 1)		/* Set bank mode for rank0 */
>>> +			clrsetbits_le32(0x3102000, 0xffc, 0x6a4);
>>> +
>>> +		/* Set bank mode for current rank */
>>> +		clrsetbits_le32(mc_work_mode, 0xffc, 0x6a4);
>>> +		udelay(1);
>>> +
>>> +		// Test if bit A23 is BA2 or mirror XXX A22?
>>> +		chk = CFG_SYS_SDRAM_BASE + (1U << 22);
>>> +		ptr = CFG_SYS_SDRAM_BASE;
>>> +		for (i = 0, j = 0; i < 64; i++) {
>>> +			if (readl(chk) != ((i & 1) ? ptr : ~ptr)) {
>>> +				j = 1;
>>> +				break;
>>> +			}
>>> +			ptr += 4;
>>> +			chk += 4;
>>> +		}
>>> +
>>> +		debug("rank %d bank = %d\n", rank, (j + 1) << 2); /* 4 or 8 */
>>> +
>>> +		/* Store banks in para 1 */
>>> +		shft = 12 + offs;
>>> +		rval = config->dram_para1;
>>> +		rval &= ~(0xf << shft);
>>> +		rval |= j << shft;
>>> +		config->dram_para1 = rval;
>>> +
>>> +		if (rank == 1)		/* Set page mode for rank0 */
>>> +			clrsetbits_le32(0x3102000, 0xffc, 0xaa0);
>>> +
>>> +		/* Set page mode for current rank */
>>> +		clrsetbits_le32(mc_work_mode, 0xffc, 0xaa0);
>>> +		udelay(1);
>>> +
>>> +		// Scan per address line, until address wraps (i.e. see shadow)
>>> +		for (i = 9; i < 14; i++) {
>>> +			chk = CFG_SYS_SDRAM_BASE + (1U << i);
>>> +			ptr = CFG_SYS_SDRAM_BASE;
>>> +			for (j = 0; j < 64; j++) {
>>> +				if (readl(chk) != ((j & 1) ? ptr : ~ptr))
>>> +					break;
>>> +				ptr += 4;
>>> +				chk += 4;
>>> +			}
>>> +			if (j == 64)
>>> +				break;
>>> +		}
>>> +		if (i > 13)
>>> +			i = 13;
>>> +
>>> +		unsigned int pgsize = (i == 9) ? 0 : (1 << (i - 10));
>>> +		debug("rank %d page size = %d KB\n", rank, pgsize);
>>> +
>>> +		/* Store page size */
>>> +		shft = offs;
>>> +		rval = config->dram_para1;
>>> +		rval &= ~(0xf << shft);
>>> +		rval |= pgsize << shft;
>>> +		config->dram_para1 = rval;
>>> +
>>> +		// Move to next rank
>>> +		rank++;
>>> +		if (rank != maxrank) {
>>> +			if (rank == 1) {
>>> +				/* MC_WORK_MODE */
>>> +				clrsetbits_le32(0x3202000, 0xffc, 0x6f0);
>>> +
>>> +				/* MC_WORK_MODE2 */
>>> +				clrsetbits_le32(0x3202004, 0xffc, 0x6f0);
>>> +			}
>>> +			/* store rank1 config in upper half of para1 */
>>> +			offs += 16;
>>> +			mc_work_mode += 4;	/* move to MC_WORK_MODE2 */
>>> +		}
>>> +	}
>>> +	if (maxrank == 2) {
>>> +		config->dram_para2 &= 0xfffff0ff;
>>> +		/* note: rval is equal to para->dram_para1 here */
>>> +		if ((rval & 0xffff) == (rval >> 16)) {
>>> +			debug("rank1 config same as rank0\n");
>>> +		} else {
>>> +			config->dram_para2 |= BIT(8);
>>> +			debug("rank1 config different from rank0\n");
>>> +		}
>>> +	}
>>> +
>>> +	return 1;
>>> +}
>>> [...]
>>> +static int sunxi_ram_probe(struct udevice *dev)
>>> +{
>>> +	struct sunxi_ram_priv *priv = dev_get_priv(dev);
>>> +	unsigned long dram_size;
>>> +
>>> +	debug("%s: %s: probing\n", __func__, dev->name);
>>> +
>>> +	dram_size = sunxi_dram_init();
>>> +	if (!dram_size) {
>>> +		printf("DRAM init failed: %d\n", ret);  
>>
>> There is no ret variable anymore, so this fails to compile. With this
>> line and the variable size issue fixed, this driver works on my Nezha
>> board, so with those fixes:
> 
> Ah, right, thanks for the heads up. I think I had some trick to compile
> test this code once, but didn't use it since last year.
> 
>> Tested-by: Samuel Holland <samuel@sholland.org>
> 
> Thanks!
> Andre
> 
> P.S. This driver has a lot of rough edges anyway (the whole
> clock/"system" setup side, for a start), but we should get things
> moving now, before the RFC version celebrates its first birthday. So I
> will merge it, but am happy to take fixes: either cleanups, or fixes
> for the D1.

Right, I'm fine with sending any fixes needed for D1 as follow-up. I'm
quite glad that we now have one version of the code that works on all
chip variants.

Regards,
Samuel
diff mbox series

Patch

diff --git a/drivers/Makefile b/drivers/Makefile
index efc2a4afb24..5a4bedf7305 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -56,6 +56,7 @@  obj-$(CONFIG_$(SPL_)ALTERA_SDRAM) += ddr/altera/
 obj-$(CONFIG_ARCH_IMX8M) += ddr/imx/imx8m/
 obj-$(CONFIG_IMX8ULP_DRAM) += ddr/imx/imx8ulp/
 obj-$(CONFIG_ARCH_IMX9) += ddr/imx/imx9/
+obj-$(CONFIG_DRAM_SUN8I_R528) += ram/
 obj-$(CONFIG_SPL_DM_RESET) += reset/
 obj-$(CONFIG_SPL_MUSB_NEW) += usb/musb-new/
 obj-$(CONFIG_SPL_USB_GADGET) += usb/gadget/
diff --git a/drivers/ram/Makefile b/drivers/ram/Makefile
index 6eb1a241359..b4750ea11c4 100644
--- a/drivers/ram/Makefile
+++ b/drivers/ram/Makefile
@@ -23,6 +23,9 @@  obj-$(CONFIG_RAM_SIFIVE) += sifive/
 ifdef CONFIG_SPL_BUILD
 obj-$(CONFIG_SPL_STARFIVE_DDR) += starfive/
 endif
+
+obj-$(CONFIG_DRAM_SUN8I_R528) += sunxi/
+
 obj-$(CONFIG_ARCH_OCTEON) += octeon/
 
 obj-$(CONFIG_ARCH_RMOBILE) += renesas/
diff --git a/drivers/ram/sunxi/Kconfig b/drivers/ram/sunxi/Kconfig
index 261d7f57409..35eeda58efa 100644
--- a/drivers/ram/sunxi/Kconfig
+++ b/drivers/ram/sunxi/Kconfig
@@ -12,3 +12,62 @@  config DRAM_SUN8I_R528
 	default y if MACH_SUN8I_R528
 	help
 	  Select this DRAM controller driver for the R528/T113s SoCs.
+
+if DRAM_SUN20I_D1 || DRAM_SUN8I_R528
+
+config DRAM_SUNXI_ODT_EN
+	hex "DRAM ODT EN parameter"
+	default 0x1
+	help
+	  ODT EN value from vendor DRAM settings.
+
+config DRAM_SUNXI_TPR0
+	hex "DRAM TPR0 parameter"
+	default 0x0
+	help
+	  TPR0 value from vendor DRAM settings.
+
+config DRAM_SUNXI_TPR11
+	hex "DRAM TPR11 parameter"
+	default 0x0
+	help
+	  TPR11 value from vendor DRAM settings.
+
+config DRAM_SUNXI_TPR12
+	hex "DRAM TPR12 parameter"
+	default 0x0
+	help
+	  TPR12 value from vendor DRAM settings.
+
+config DRAM_SUNXI_TPR13
+	hex "DRAM TPR13 parameter"
+	default 0x0
+	help
+	  TPR13 value from vendor DRAM settings. It tells which features
+	  should be configured.
+
+choice
+	prompt "DRAM chip type"
+	default SUNXI_DRAM_TYPE_DDR3 if DRAM_SUN8I_R528 || DRAM_SUN20I_D1
+
+config SUNXI_DRAM_TYPE_DDR2
+        bool "DDR2 chips"
+
+config SUNXI_DRAM_TYPE_DDR3
+        bool "DDR3 chips"
+
+config SUNXI_DRAM_TYPE_LPDDR2
+        bool "LPDDR2 chips"
+
+config SUNXI_DRAM_TYPE_LPDDR3
+        bool "LPDDR3 chips"
+endchoice
+
+config SUNXI_DRAM_TYPE
+	int
+	default 2 if SUNXI_DRAM_TYPE_DDR2
+	default 3 if SUNXI_DRAM_TYPE_DDR3
+	default 6 if SUNXI_DRAM_TYPE_LPDDR2
+	default 7 if SUNXI_DRAM_TYPE_LPDDR3
+
+endif
diff --git a/drivers/ram/sunxi/Makefile b/drivers/ram/sunxi/Makefile
new file mode 100644
index 00000000000..d6fb2cf0b65
--- /dev/null
+++ b/drivers/ram/sunxi/Makefile
@@ -0,0 +1,4 @@ 
+# SPDX-License-Identifier: GPL-2.0+
+
+obj-$(CONFIG_DRAM_SUN20I_D1) += dram_sun20i_d1.o
+obj-$(CONFIG_DRAM_SUN8I_R528) += dram_sun20i_d1.o
diff --git a/drivers/ram/sunxi/dram_sun20i_d1.c b/drivers/ram/sunxi/dram_sun20i_d1.c
new file mode 100644
index 00000000000..c766fc24065
--- /dev/null
+++ b/drivers/ram/sunxi/dram_sun20i_d1.c
@@ -0,0 +1,1432 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Allwinner D1/D1s/R528/T113-sx DRAM initialisation
+ *
+ * As usual there is no documentation for the memory controller or PHY IP
+ * used here. The baseline of this code was lifted from awboot[1], which
+ * seems to be based on some form of de-compilation of some original Allwinner
+ * code bits (with a GPL2 license tag from the very beginning).
+ * This version here is a reworked version, to match the U-Boot coding style
+ * and style of the other Allwinner DRAM drivers.
+ *
+ * [1] https://github.com/szemzoa/awboot.git
+ */
+
+#include <asm/io.h>
+#include <common.h>
+#ifdef CONFIG_RAM
+  #include <dm.h>
+  #include <ram.h>
+#endif
+#include <linux/delay.h>
+
+#include "dram_sun20i_d1.h"
+
+#ifndef SUNXI_SID_BASE
+#define SUNXI_SID_BASE	0x3006200
+#endif
+
+#ifndef SUNXI_CCM_BASE
+#define SUNXI_CCM_BASE	0x2001000
+#endif
+
+static void sid_read_ldoB_cal(const dram_para_t *para)
+{
+	uint32_t reg;
+
+	reg = (readl(SUNXI_SID_BASE + 0x1c) & 0xff00) >> 8;
+
+	if (reg == 0)
+		return;
+
+	switch (para->dram_type) {
+	case SUNXI_DRAM_TYPE_DDR2:
+		break;
+	case SUNXI_DRAM_TYPE_DDR3:
+		if (reg > 0x20)
+			reg -= 0x16;
+		break;
+	default:
+		reg = 0;
+		break;
+	}
+
+	clrsetbits_le32(0x3000150, 0xff00, reg << 8);
+}
+
+static void dram_voltage_set(const dram_para_t *para)
+{
+	int vol;
+
+	switch (para->dram_type) {
+	case SUNXI_DRAM_TYPE_DDR2:
+		vol = 47;
+		break;
+	case SUNXI_DRAM_TYPE_DDR3:
+		vol = 25;
+		break;
+	default:
+		vol = 0;
+		break;
+	}
+
+	clrsetbits_le32(0x3000150, 0x20ff00, vol << 8);
+
+	udelay(1);
+
+	sid_read_ldoB_cal(para);
+}
+
+static void dram_enable_all_master(void)
+{
+	writel(~0, 0x3102020);
+	writel(0xff, 0x3102024);
+	writel(0xffff, 0x3102028);
+	udelay(10);
+}
+
+static void dram_disable_all_master(void)
+{
+	writel(1, 0x3102020);
+	writel(0, 0x3102024);
+	writel(0, 0x3102028);
+	udelay(10);
+}
+
+static void eye_delay_compensation(const dram_para_t *para)
+{
+	uint32_t delay;
+	unsigned long ptr;
+
+	// DATn0IOCR, n =  0...7
+	delay = (para->dram_tpr11 & 0xf) << 9;
+	delay |= (para->dram_tpr12 & 0xf) << 1;
+	for (ptr = 0x3103310; ptr < 0x3103334; ptr += 4)
+		setbits_le32(ptr, delay);
+
+	// DATn1IOCR, n =  0...7
+	delay = (para->dram_tpr11 & 0xf0) << 5;
+	delay |= (para->dram_tpr12 & 0xf0) >> 3;
+	for (ptr = 0x3103390; ptr != 0x31033b4; ptr += 4)
+		setbits_le32(ptr, delay);
+
+	// PGCR0: assert AC loopback FIFO reset
+	clrbits_le32(0x3103100, 0x04000000);
+
+	// ??
+
+	delay = (para->dram_tpr11 & 0xf0000) >> 7;
+	delay |= (para->dram_tpr12 & 0xf0000) >> 15;
+	setbits_le32(0x3103334, delay);
+	setbits_le32(0x3103338, delay);
+
+	delay = (para->dram_tpr11 & 0xf00000) >> 11;
+	delay |= (para->dram_tpr12 & 0xf00000) >> 19;
+	setbits_le32(0x31033b4, delay);
+	setbits_le32(0x31033b8, delay);
+
+	setbits_le32(0x310333c, (para->dram_tpr11 & 0xf0000) << 9);
+	setbits_le32(0x31033bc, (para->dram_tpr11 & 0xf00000) << 5);
+
+	// PGCR0: release AC loopback FIFO reset
+	setbits_le32(0x3103100, BIT(26));
+
+	udelay(1);
+
+	delay = (para->dram_tpr10 & 0xf0) << 4;
+	for (ptr = 0x3103240; ptr != 0x310327c; ptr += 4)
+		setbits_le32(ptr, delay);
+	for (ptr = 0x3103228; ptr != 0x3103240; ptr += 4)
+		setbits_le32(ptr, delay);
+
+	setbits_le32(0x3103218, (para->dram_tpr10 & 0x0f) << 8);
+	setbits_le32(0x310321c, (para->dram_tpr10 & 0x0f) << 8);
+
+	setbits_le32(0x3103280, (para->dram_tpr10 & 0xf00) >> 4);
+}
+
+/*
+ * Main purpose of the auto_set_timing routine seems to be to calculate all
+ * timing settings for the specific type of sdram used. Read together with
+ * an sdram datasheet for context on the various variables.
+ */
+static void mctl_set_timing_params(const dram_para_t *para,
+				   const dram_config_t *config)
+{
+	/* DRAM_TPR0 */
+	u8 tccd		= 2;
+	u8 tfaw;
+	u8 trrd;
+	u8 trcd;
+	u8 trc;
+
+	/* DRAM_TPR1 */
+	u8 txp;
+	u8 twtr;
+	u8 trtp		= 4;
+	u8 twr;
+	u8 trp;
+	u8 tras;
+
+	/* DRAM_TPR2 */
+	u16 trefi;
+	u16 trfc;
+
+	u8 tcksrx;
+	u8 tckesr;
+	u8 trd2wr;
+	u8 twr2rd;
+	u8 trasmax;
+	u8 twtp;
+	u8 tcke;
+	u8 tmod;
+	u8 tmrd;
+	u8 tmrw;
+
+	u8 tcl;
+	u8 tcwl;
+	u8 t_rdata_en;
+	u8 wr_latency;
+
+	u32 mr0;
+	u32 mr1;
+	u32 mr2;
+	u32 mr3;
+
+	u32 tdinit0;
+	u32 tdinit1;
+	u32 tdinit2;
+	u32 tdinit3;
+
+	switch (para->dram_type) {
+	case SUNXI_DRAM_TYPE_DDR2:
+		/* DRAM_TPR0 */
+		tfaw		= ns_to_t(50);
+		trrd		= ns_to_t(10);
+		trcd		= ns_to_t(20);
+		trc		= ns_to_t(65);
+
+		/* DRAM_TPR1 */
+		txp		= 2;
+		twtr		= ns_to_t(8);
+		twr		= ns_to_t(15);
+		trp		= ns_to_t(15);
+		tras		= ns_to_t(45);
+
+		/* DRAM_TRP2 */
+		trfc		= ns_to_t(328);
+		trefi		= ns_to_t(7800) / 32;
+
+		trasmax		= CONFIG_DRAM_CLK / 30;
+		if (CONFIG_DRAM_CLK < 409) {
+			t_rdata_en	= 1;
+			tcl		= 3;
+			mr0		= 0x06a3;
+		} else {
+			t_rdata_en	= 2;
+			tcl		= 4;
+			mr0		= 0x0e73;
+		}
+		tmrd		= 2;
+		twtp		= twr + 5;
+		tcksrx		= 5;
+		tckesr		= 4;
+		trd2wr		= 4;
+		tcke		= 3;
+		tmod		= 12;
+		wr_latency	= 1;
+		tmrw		= 0;
+		twr2rd		= twtr + 5;
+		tcwl		= 0;
+
+		mr1		= para->dram_mr1;
+		mr2		= 0;
+		mr3		= 0;
+
+		tdinit0		= 200 * CONFIG_DRAM_CLK + 1;
+		tdinit1		= 100 * CONFIG_DRAM_CLK / 1000 + 1;
+		tdinit2		= 200 * CONFIG_DRAM_CLK + 1;
+		tdinit3		= 1 * CONFIG_DRAM_CLK + 1;
+
+		break;
+	case SUNXI_DRAM_TYPE_DDR3:
+		trfc		= ns_to_t(350);
+		trefi		= ns_to_t(7800) / 32 + 1;	// XXX
+
+		twtr		= ns_to_t(8) + 2;		// + 2 ? XXX
+		/* Only used by trd2wr calculation, which gets discard below */
+//		twr		= max(ns_to_t(15), 2);
+		trrd		= max(ns_to_t(10), 2);
+		txp		= max(ns_to_t(10), 2);
+
+		if (CONFIG_DRAM_CLK <= 800) {
+			tfaw		= ns_to_t(50);
+			trcd		= ns_to_t(15);
+			trp		= ns_to_t(15);
+			trc		= ns_to_t(53);
+			tras		= ns_to_t(38);
+
+			mr0		= 0x1c70;
+			mr2		= 0x18;
+			tcl		= 6;
+			wr_latency	= 2;
+			tcwl		= 4;
+			t_rdata_en	= 4;
+		} else {
+			tfaw		= ns_to_t(35);
+			trcd		= ns_to_t(14);
+			trp		= ns_to_t(14);
+			trc		= ns_to_t(48);
+			tras		= ns_to_t(34);
+
+			mr0		= 0x1e14;
+			mr2		= 0x20;
+			tcl		= 7;
+			wr_latency	= 3;
+			tcwl		= 5;
+			t_rdata_en	= 5;
+		}
+
+		trasmax		= CONFIG_DRAM_CLK / 30;
+		twtp		= tcwl + 2 + twtr;		// WL+BL/2+tWTR
+		/* Gets overwritten below */
+//		trd2wr		= tcwl + 2 + twr;		// WL+BL/2+tWR
+		twr2rd		= tcwl + twtr;			// WL+tWTR
+
+		tdinit0		= 500 * CONFIG_DRAM_CLK + 1;	// 500 us
+		tdinit1		= 360 * CONFIG_DRAM_CLK / 1000 + 1;   // 360 ns
+		tdinit2		= 200 * CONFIG_DRAM_CLK + 1;	// 200 us
+		tdinit3		= 1 * CONFIG_DRAM_CLK + 1;	//   1 us
+
+		mr1		= para->dram_mr1;
+		mr3		= 0;
+		tcke		= 3;
+		tcksrx		= 5;
+		tckesr		= 4;
+		if (((config->dram_tpr13 & 0xc) == 0x04) || CONFIG_DRAM_CLK < 912)
+			trd2wr	   = 5;
+		else
+			trd2wr	   = 6;
+
+		tmod		= 12;
+		tmrd		= 4;
+		tmrw		= 0;
+
+		break;
+	case SUNXI_DRAM_TYPE_LPDDR2:
+		tfaw		= max(ns_to_t(50), 4);
+		trrd		= max(ns_to_t(10), 1);
+		trcd		= max(ns_to_t(24), 2);
+		trc		= ns_to_t(70);
+		txp		= ns_to_t(8);
+		if (txp < 2) {
+			txp++;
+			twtr	= 2;
+		} else {
+			twtr	= txp;
+		}
+		twr		= max(ns_to_t(15), 2);
+		trp		= ns_to_t(17);
+		tras		= ns_to_t(42);
+		trefi		= ns_to_t(3900) / 32;
+		trfc		= ns_to_t(210);
+
+		trasmax		= CONFIG_DRAM_CLK / 60;
+		mr3		= para->dram_mr3;
+		twtp		= twr + 5;
+		mr2		= 6;
+		mr1		= 5;
+		tcksrx		= 5;
+		tckesr		= 5;
+		trd2wr		= 10;
+		tcke		= 2;
+		tmod		= 5;
+		tmrd		= 5;
+		tmrw		= 3;
+		tcl		= 4;
+		wr_latency	= 1;
+		t_rdata_en	= 1;
+
+		tdinit0		= 200 * CONFIG_DRAM_CLK + 1;
+		tdinit1		= 100 * CONFIG_DRAM_CLK / 1000 + 1;
+		tdinit2		= 11 * CONFIG_DRAM_CLK + 1;
+		tdinit3		= 1 * CONFIG_DRAM_CLK + 1;
+		twr2rd		= twtr + 5;
+		tcwl		= 2;
+		mr1		= 195;
+		mr0		= 0;
+
+		break;
+	case SUNXI_DRAM_TYPE_LPDDR3:
+		tfaw		= max(ns_to_t(50), 4);
+		trrd		= max(ns_to_t(10), 1);
+		trcd		= max(ns_to_t(24), 2);
+		trc		= ns_to_t(70);
+		twtr		= max(ns_to_t(8), 2);
+		twr		= max(ns_to_t(15), 2);
+		trp		= ns_to_t(17);
+		tras		= ns_to_t(42);
+		trefi		= ns_to_t(3900) / 32;
+		trfc		= ns_to_t(210);
+		txp		= twtr;
+
+		trasmax		= CONFIG_DRAM_CLK / 60;
+		if (CONFIG_DRAM_CLK < 800) {
+			tcwl	   = 4;
+			wr_latency = 3;
+			t_rdata_en = 6;
+			mr2		   = 12;
+		} else {
+			tcwl	   = 3;
+			tcke	   = 6;
+			wr_latency = 2;
+			t_rdata_en = 5;
+			mr2		   = 10;
+		}
+		twtp		= tcwl + 5;
+		tcl		= 7;
+		mr3		= para->dram_mr3;
+		tcksrx		= 5;
+		tckesr		= 5;
+		trd2wr		= 13;
+		tcke		= 3;
+		tmod		= 12;
+		tdinit0		= 400 * CONFIG_DRAM_CLK + 1;
+		tdinit1		= 500 * CONFIG_DRAM_CLK / 1000 + 1;
+		tdinit2		= 11 * CONFIG_DRAM_CLK + 1;
+		tdinit3		= 1 * CONFIG_DRAM_CLK + 1;
+		tmrd		= 5;
+		tmrw		= 5;
+		twr2rd		= tcwl + twtr + 5;
+		mr1		= 195;
+		mr0		= 0;
+
+		break;
+	default:
+		trfc		= 128;
+		trp		= 6;
+		trefi		= 98;
+		txp		= 10;
+		twr		= 8;
+		twtr		= 3;
+		tras		= 14;
+		tfaw		= 16;
+		trc		= 20;
+		trcd		= 6;
+		trrd		= 3;
+
+		twr2rd		= 8;
+		tcksrx		= 4;
+		tckesr		= 3;
+		trd2wr		= 4;
+		trasmax		= 27;
+		twtp		= 12;
+		tcke		= 2;
+		tmod		= 6;
+		tmrd		= 2;
+		tmrw		= 0;
+		tcwl		= 3;
+		tcl		= 3;
+		wr_latency	= 1;
+		t_rdata_en	= 1;
+		mr3		= 0;
+		mr2		= 0;
+		mr1		= 0;
+		mr0		= 0;
+		tdinit3		= 0;
+		tdinit2		= 0;
+		tdinit1		= 0;
+		tdinit0		= 0;
+
+		break;
+	}
+
+	/* Set mode registers */
+	writel(mr0, 0x3103030);
+	writel(mr1, 0x3103034);
+	writel(mr2, 0x3103038);
+	writel(mr3, 0x310303c);
+	/* TODO: dram_odt_en is either 0x0 or 0x1, so right shift looks weird */
+	writel((para->dram_odt_en >> 4) & 0x3, 0x310302c);
+
+	/* Set dram timing DRAMTMG0 - DRAMTMG5 */
+	writel((twtp << 24) | (tfaw << 16) | (trasmax << 8) | (tras << 0),
+		0x3103058);
+	writel((txp << 16) | (trtp << 8) | (trc << 0),
+		0x310305c);
+	writel((tcwl << 24) | (tcl << 16) | (trd2wr << 8) | (twr2rd << 0),
+		0x3103060);
+	writel((tmrw << 16) | (tmrd << 12) | (tmod << 0),
+		0x3103064);
+	writel((trcd << 24) | (tccd << 16) | (trrd << 8) | (trp << 0),
+		0x3103068);
+	writel((tcksrx << 24) | (tcksrx << 16) | (tckesr << 8) | (tcke << 0),
+		0x310306c);
+
+	/* Set dual rank timing */
+	clrsetbits_le32(0x3103078, 0xf000ffff,
+			(CONFIG_DRAM_CLK < 800) ? 0xf0006610 : 0xf0007610);
+
+	/* Set phy interface time PITMG0, PTR3, PTR4 */
+	writel((0x2 << 24) | (t_rdata_en << 16) | BIT(8) | (wr_latency << 0),
+		0x3103080);
+	writel(((tdinit0 << 0) | (tdinit1 << 20)), 0x3103050);
+	writel(((tdinit2 << 0) | (tdinit3 << 20)), 0x3103054);
+
+	/* Set refresh timing and mode */
+	writel((trefi << 16) | (trfc << 0), 0x3103090);
+	writel((trefi << 15) & 0x0fff0000, 0x3103094);
+}
+
+// Purpose of this routine seems to be to initialize the PLL driving
+// the MBUS and sdram.
+//
+static int ccu_set_pll_ddr_clk(int index, const dram_para_t *para,
+			       const dram_config_t *config)
+{
+	unsigned int val, clk, n;
+
+	if (config->dram_tpr13 & BIT(6))
+		clk = para->dram_tpr9;
+	else
+		clk = para->dram_clk;
+
+	// set VCO clock divider
+	n = (clk * 2) / 24;
+
+	val = readl(SUNXI_CCM_BASE + 0x10);
+	val &= ~0x0007ff03;			// clear dividers
+	val |= (n - 1) << 8;			// set PLL division
+	val |= BIT(31) | BIT(30);		// enable PLL and LDO
+	writel(val | BIT(29), SUNXI_CCM_BASE + 0x10);
+
+	// wait for PLL to lock
+	while ((readl(SUNXI_CCM_BASE + 0x10) & BIT(28)) == 0)
+		;
+
+	udelay(20);
+
+	// enable PLL output
+	setbits_le32(SUNXI_CCM_BASE + 0x0, BIT(27));
+
+	// turn clock gate on
+	val = readl(SUNXI_CCM_BASE + 0x800);
+	val &= ~0x03000303;		// select DDR clk source, n=1, m=1
+	val |= BIT(31);			// turn clock on
+	writel(val, SUNXI_CCM_BASE + 0x800);
+
+	return n * 24;
+}
+
+/* Set up the PLL and clock gates for the DRAM controller and MBUS clocks. */
+static void mctl_sys_init(const dram_para_t *para, const dram_config_t *config)
+{
+	// assert MBUS reset
+	clrbits_le32(SUNXI_CCM_BASE + 0x540, BIT(30));
+
+	// turn off sdram clock gate, assert sdram reset
+	clrbits_le32(SUNXI_CCM_BASE + 0x80c, 0x10001);
+	clrsetbits_le32(SUNXI_CCM_BASE + 0x800, BIT(31) | BIT(30), BIT(27));
+	udelay(10);
+
+	// set ddr pll clock
+	ccu_set_pll_ddr_clk(0, para, config);
+	udelay(100);
+	dram_disable_all_master();
+
+	// release sdram reset
+	setbits_le32(SUNXI_CCM_BASE + 0x80c, BIT(16));
+
+	// release MBUS reset
+	setbits_le32(SUNXI_CCM_BASE + 0x540, BIT(30));
+	setbits_le32(SUNXI_CCM_BASE + 0x800, BIT(30));
+
+	udelay(5);
+
+	// turn on sdram clock gate
+	setbits_le32(SUNXI_CCM_BASE + 0x80c, BIT(0));
+
+	// turn dram clock gate on, trigger sdr clock update
+	setbits_le32(SUNXI_CCM_BASE + 0x800, BIT(31) | BIT(27));
+	udelay(5);
+
+	// mCTL clock enable
+	writel(0x8000, 0x310300c);
+	udelay(10);
+}
+
+// The main purpose of this routine seems to be to copy an address configuration
+// from the dram_para1 and dram_para2 fields to the PHY configuration registers
+// (0x3102000, 0x3102004).
+//
+static void mctl_com_init(const dram_para_t *para, const dram_config_t *config)
+{
+	uint32_t val, width;
+	unsigned long ptr;
+	int i;
+
+	// purpose ??
+	clrsetbits_le32(0x3102008, 0x3f00, 0x2000);
+
+	// set SDRAM type and word width
+	val  = readl(0x3102000) & ~0x00fff000;
+	val |= (para->dram_type & 0x7) << 16;		// DRAM type
+	val |= (~config->dram_para2 & 0x1) << 12;		// DQ width
+	val |= BIT(22);					// ??
+	if (para->dram_type == SUNXI_DRAM_TYPE_LPDDR2 ||
+	    para->dram_type == SUNXI_DRAM_TYPE_LPDDR3) {
+		val |= BIT(19);		// type 6 and 7 must use 1T
+	} else {
+		if (config->dram_tpr13 & BIT(5))
+			val |= BIT(19);
+	}
+	writel(val, 0x3102000);
+
+	// init rank / bank / row for single/dual or two different ranks
+	if ((config->dram_para2 & BIT(8)) &&
+	    ((config->dram_para2 & 0xf000) != 0x1000))
+		width = 32;
+	else
+		width = 16;
+
+	ptr = 0x3102000;
+	for (i = 0; i < width; i += 16) {
+		val = readl(ptr) & 0xfffff000;
+
+		val |= (config->dram_para2 >> 12) & 0x3; // rank
+		val |= ((config->dram_para1 >> (i + 12)) << 2) & 0x4; // bank - 2
+		val |= (((config->dram_para1 >> (i + 4)) - 1) << 4) & 0xff; // row - 1
+
+		// convert from page size to column addr width - 3
+		switch ((config->dram_para1 >> i) & 0xf) {
+		case 8: val |= 0xa00; break;
+		case 4: val |= 0x900; break;
+		case 2: val |= 0x800; break;
+		case 1: val |= 0x700; break;
+		default: val |= 0x600; break;
+		}
+		writel(val, ptr);
+		ptr += 4;
+	}
+
+	// set ODTMAP based on number of ranks in use
+	val = (readl(0x3102000) & 0x1) ? 0x303 : 0x201;
+	writel(val, 0x3103120);
+
+	// set mctl reg 3c4 to zero when using half DQ
+	if (config->dram_para2 & BIT(0))
+		writel(0, 0x31033c4);
+
+	// purpose ??
+	if (para->dram_tpr4) {
+                setbits_le32(0x3102000, (para->dram_tpr4 & 0x3) << 25);
+                setbits_le32(0x3102004, (para->dram_tpr4 & 0x7fc) << 10);
+	}
+}
+
+static const uint8_t ac_remapping_tables[][22] = {
+	[0] = { 0 },
+	[1] = {  1,  9,  3,  7,  8, 18,  4, 13,  5,  6, 10,
+		 2, 14, 12,  0,  0, 21, 17, 20, 19, 11, 22 },
+	[2] = {  4,  9,  3,  7,  8, 18,  1, 13,  2,  6, 10,
+		 5, 14, 12,  0,  0, 21, 17, 20, 19, 11, 22 },
+	[3] = {  1,  7,  8, 12, 10, 18,  4, 13,  5,  6,  3,
+		 2,  9,  0,  0,  0, 21, 17, 20, 19, 11, 22 },
+	[4] = {  4, 12, 10,  7,  8, 18,  1, 13,  2,  6,  3,
+		 5,  9,  0,  0,  0, 21, 17, 20, 19, 11, 22 },
+	[5] = { 13,  2,  7,  9, 12, 19,  5,  1,  6,  3,  4,
+		 8, 10,  0,  0,  0, 21, 22, 18, 17, 11, 20 },
+	[6] = {  3, 10,  7, 13,  9, 11,  1,  2,  4,  6,  8,
+		 5, 12,  0,  0,  0, 20,  1,  0, 21, 22, 17 },
+	[7] = {  3,  2,  4,  7,  9,  1, 17, 12, 18, 14, 13,
+		 8, 15,  6, 10,  5, 19, 22, 16, 21, 20, 11 },
+};
+
+/*
+ * This routine chooses one of several remapping tables for 22 lines.
+ * It is unclear which lines are being remapped. It seems to pick
+ * table cfg7 for the Nezha board.
+ */
+static void mctl_phy_ac_remapping(const dram_para_t *para,
+				  const dram_config_t *config)
+{
+	const uint8_t *cfg;
+	uint32_t fuse, val;
+
+	/*
+	 * It is unclear whether the LPDDRx types don't need any remapping,
+	 * or whether the original code just didn't provide tables.
+	 */
+	if (para->dram_type != SUNXI_DRAM_TYPE_DDR2 &&
+	    para->dram_type != SUNXI_DRAM_TYPE_DDR3)
+		return;
+
+	fuse = (readl(SUNXI_SID_BASE + 0x28) & 0xf00) >> 8;
+	debug("DDR efuse: 0x%x\n", fuse);
+
+	if (para->dram_type == SUNXI_DRAM_TYPE_DDR2) {
+		if (fuse == 15)
+			return;
+		cfg = ac_remapping_tables[6];
+	} else {
+		if (config->dram_tpr13 & 0xc0000) {
+			cfg = ac_remapping_tables[7];
+		} else {
+			switch (fuse) {
+			case 8: cfg = ac_remapping_tables[2]; break;
+			case 9: cfg = ac_remapping_tables[3]; break;
+			case 10: cfg = ac_remapping_tables[5]; break;
+			case 11: cfg = ac_remapping_tables[4]; break;
+			default:
+			case 12: cfg = ac_remapping_tables[1]; break;
+			case 13:
+			case 14: cfg = ac_remapping_tables[0]; break;
+			}
+		}
+	}
+
+	val = (cfg[4] << 25) | (cfg[3] << 20) | (cfg[2] << 15) |
+	      (cfg[1] << 10) | (cfg[0] << 5);
+	writel(val, 0x3102500);
+
+	val = (cfg[10] << 25) | (cfg[9] << 20) | (cfg[8] << 15) |
+	      (cfg[ 7] << 10) | (cfg[6] <<  5) | cfg[5];
+	writel(val, 0x3102504);
+
+	val = (cfg[15] << 20) | (cfg[14] << 15) | (cfg[13] << 10) |
+	      (cfg[12] <<  5) | cfg[11];
+	writel(val, 0x3102508);
+
+	val = (cfg[21] << 25) | (cfg[20] << 20) | (cfg[19] << 15) |
+	      (cfg[18] << 10) | (cfg[17] <<  5) | cfg[16];
+	writel(val, 0x310250c);
+
+	val = (cfg[4] << 25) | (cfg[3] << 20) | (cfg[2] << 15) |
+	      (cfg[1] << 10) | (cfg[0] <<  5) | 1;
+	writel(val, 0x3102500);
+}
+
+// Init the controller channel. The key part is placing commands in the main
+// command register (PIR, 0x3103000) and checking command status (PGSR0, 0x3103010).
+//
+static unsigned int mctl_channel_init(unsigned int ch_index,
+				      const dram_para_t *para,
+				      const dram_config_t *config)
+{
+	unsigned int val, dqs_gating_mode;
+
+	dqs_gating_mode = (config->dram_tpr13 & 0xc) >> 2;
+
+	// set DDR clock to half of CPU clock
+	clrsetbits_le32(0x310200c, 0xfff, (para->dram_clk / 2) - 1);
+
+	// MRCTRL0 nibble 3 undocumented
+	clrsetbits_le32(0x3103108, 0xf00, 0x300);
+
+	if (para->dram_odt_en)
+		val = 0;
+	else
+		val = BIT(5);
+
+	// DX0GCR0
+	if (para->dram_clk > 672)
+		clrsetbits_le32(0x3103344, 0xf63e, val);
+	else
+		clrsetbits_le32(0x3103344, 0xf03e, val);
+
+	// DX1GCR0
+	if (para->dram_clk > 672) {
+                setbits_le32(0x3103344, 0x400);
+		clrsetbits_le32(0x31033c4, 0xf63e, val);
+	} else {
+		clrsetbits_le32(0x31033c4, 0xf03e, val);
+	}
+
+	// 0x3103208 undocumented
+	setbits_le32(0x3103208, BIT(1));
+
+	eye_delay_compensation(para);
+
+	// set PLL SSCG ?
+	val = readl(0x3103108);
+	if (dqs_gating_mode == 1) {
+		clrsetbits_le32(0x3103108, 0xc0, 0);
+		clrbits_le32(0x31030bc, 0x107);
+	} else if (dqs_gating_mode == 2) {
+		clrsetbits_le32(0x3103108, 0xc0, 0x80);
+
+		clrsetbits_le32(0x31030bc, 0x107,
+				(((config->dram_tpr13 >> 16) & 0x1f) - 2) | 0x100);
+		clrsetbits_le32(0x310311c, BIT(31), BIT(27));
+	} else {
+		clrbits_le32(0x3103108, 0x40);
+		udelay(10);
+		setbits_le32(0x3103108, 0xc0);
+	}
+
+	if (para->dram_type == SUNXI_DRAM_TYPE_LPDDR2 ||
+	    para->dram_type == SUNXI_DRAM_TYPE_LPDDR3) {
+		if (dqs_gating_mode == 1)
+			clrsetbits_le32(0x310311c, 0x080000c0, 0x80000000);
+		else
+			clrsetbits_le32(0x310311c, 0x77000000, 0x22000000);
+	}
+
+	clrsetbits_le32(0x31030c0, 0x0fffffff,
+			(config->dram_para2 & BIT(12)) ? 0x03000001 : 0x01000007);
+
+	if (readl(0x70005d4) & BIT(16)) {
+		clrbits_le32(0x7010250, 0x2);
+		udelay(10);
+	}
+
+	// Set ZQ config
+	clrsetbits_le32(0x3103140, 0x3ffffff,
+			(para->dram_zq & 0x00ffffff) | BIT(25));
+
+	// Initialise DRAM controller
+	if (dqs_gating_mode == 1) {
+		//writel(0x52, 0x3103000); // prep PHY reset + PLL init + z-cal
+		writel(0x53, 0x3103000); // Go
+
+		while ((readl(0x3103010) & 0x1) == 0) {
+		} // wait for IDONE
+		udelay(10);
+
+		// 0x520 = prep DQS gating + DRAM init + d-cal
+		if (para->dram_type == SUNXI_DRAM_TYPE_DDR3)
+			writel(0x5a0, 0x3103000);		// + DRAM reset
+		else
+			writel(0x520, 0x3103000);
+	} else {
+		if ((readl(0x70005d4) & (1 << 16)) == 0) {
+			// prep DRAM init + PHY reset + d-cal + PLL init + z-cal
+			if (para->dram_type == SUNXI_DRAM_TYPE_DDR3)
+				writel(0x1f2, 0x3103000);	// + DRAM reset
+			else
+				writel(0x172, 0x3103000);
+		} else {
+			// prep PHY reset + d-cal + z-cal
+			writel(0x62, 0x3103000);
+		}
+	}
+
+	setbits_le32(0x3103000, 0x1);		 // GO
+
+	udelay(10);
+	while ((readl(0x3103010) & 0x1) == 0) {
+	} // wait for IDONE
+
+	if (readl(0x70005d4) & BIT(16)) {
+		clrsetbits_le32(0x310310c, 0x06000000, 0x04000000);
+		udelay(10);
+
+		setbits_le32(0x3103004, 0x1);
+
+		while ((readl(0x3103018) & 0x7) != 0x3) {
+		}
+
+		clrbits_le32(0x7010250, 0x1);
+		udelay(10);
+
+		clrbits_le32(0x3103004, 0x1);
+
+		while ((readl(0x3103018) & 0x7) != 0x1) {
+		}
+
+		udelay(15);
+
+		if (dqs_gating_mode == 1) {
+			clrbits_le32(0x3103108, 0xc0);
+			clrsetbits_le32(0x310310c, 0x06000000, 0x02000000);
+			udelay(1);
+			writel(0x401, 0x3103000);
+
+			while ((readl(0x3103010) & 0x1) == 0) {
+			}
+		}
+	}
+
+	// Check for training error
+	if (readl(0x3103010) & BIT(20)) {
+		printf("ZQ calibration error, check external 240 ohm resistor\n");
+		return 0;
+	}
+
+	// STATR = Zynq STAT? Wait for status 'normal'?
+	while ((readl(0x3103018) & 0x1) == 0) {
+	}
+
+	setbits_le32(0x310308c, BIT(31));
+	udelay(10);
+	clrbits_le32(0x310308c, BIT(31));
+	udelay(10);
+	setbits_le32(0x3102014, BIT(31));
+	udelay(10);
+
+	clrbits_le32(0x310310c, 0x06000000);
+
+	if (dqs_gating_mode == 1)
+		clrsetbits_le32(0x310311c, 0xc0, 0x40);
+
+	return 1;
+}
+
+static unsigned int calculate_rank_size(uint32_t regval)
+{
+	unsigned int bits;
+
+	bits = (regval >> 8) & 0xf;	/* page size - 3 */
+	bits += (regval >> 4) & 0xf;	/* row width - 1 */
+	bits += (regval >> 2) & 0x3;	/* bank count - 2 */
+	bits -= 14;			/* 1MB = 20 bits, minus above 6 = 14 */
+
+	return 1U << bits;
+}
+
+/*
+ * The below routine reads the dram config registers and extracts
+ * the number of address bits in each rank available. It then calculates
+ * total memory size in MB.
+ */
+static unsigned int DRAMC_get_dram_size(void)
+{
+	uint32_t val;
+	unsigned int size;
+
+	val = readl(0x3102000);		/* MC_WORK_MODE0 */
+	size = calculate_rank_size(val);
+	if ((val & 0x3) == 0)		/* single rank? */
+		return size;
+
+	val = readl(0x3102004);		/* MC_WORK_MODE1 */
+	if ((val & 0x3) == 0)		/* two identical ranks? */
+		return size * 2;
+
+	/* add sizes of both ranks */
+	return size + calculate_rank_size(val);
+}
+
+/*
+ * The below routine reads the command status register to extract
+ * DQ width and rank count. This follows the DQS training command in
+ * channel_init. If error bit 22 is reset, we have two ranks and full DQ.
+ * If there was an error, figure out whether it was half DQ, single rank,
+ * or both. Set bit 12 and 0 in dram_para2 with the results.
+ */
+static int dqs_gate_detect(dram_config_t *config)
+{
+	uint32_t dx0, dx1;
+
+	if ((readl(0x3103010) & BIT(22)) == 0) {
+		config->dram_para2 = (config->dram_para2 & ~0xf) | BIT(12);
+		debug("dual rank and full DQ\n");
+
+		return 1;
+	}
+
+	dx0 = (readl(0x3103348) & 0x3000000) >> 24;
+	if (dx0 == 0) {
+		config->dram_para2 = (config->dram_para2 & ~0xf) | 0x1001;
+		debug("dual rank and half DQ\n");
+
+		return 1;
+	}
+
+	if (dx0 == 2) {
+		dx1 = (readl(0x31033c8) & 0x3000000) >> 24;
+		if (dx1 == 2) {
+			config->dram_para2 = config->dram_para2 & ~0xf00f;
+			debug("single rank and full DQ\n");
+		} else {
+			config->dram_para2 = (config->dram_para2 & ~0xf00f) | BIT(0);
+			debug("single rank and half DQ\n");
+		}
+
+		return 1;
+	}
+
+	if ((config->dram_tpr13 & BIT(29)) == 0)
+		return 0;
+
+	debug("DX0 state: %d\n", dx0);
+	debug("DX1 state: %d\n", dx1);
+
+	return 0;
+}
+
+static int dramc_simple_wr_test(unsigned int mem_mb, int len)
+{
+	unsigned int  offs	= (mem_mb / 2) << 18; // half of memory size
+	unsigned int  patt1 = 0x01234567;
+	unsigned int  patt2 = 0xfedcba98;
+	unsigned int *addr, v1, v2, i;
+
+	addr = (unsigned int *)CFG_SYS_SDRAM_BASE;
+	for (i = 0; i != len; i++, addr++) {
+		writel(patt1 + i, (unsigned long)addr);
+		writel(patt2 + i, (unsigned long)(addr + offs));
+	}
+
+	addr = (unsigned int *)CFG_SYS_SDRAM_BASE;
+	for (i = 0; i != len; i++) {
+		v1 = readl((unsigned long)(addr + i));
+		v2 = patt1 + i;
+		if (v1 != v2) {
+			printf("DRAM: simple test FAIL\n");
+			printf("%x != %x at address %p\n", v1, v2, addr + i);
+			return 1;
+		}
+		v1 = readl((unsigned long)(addr + offs + i));
+		v2 = patt2 + i;
+		if (v1 != v2) {
+			printf("DRAM: simple test FAIL\n");
+			printf("%x != %x at address %p\n", v1, v2, addr + offs + i);
+			return 1;
+		}
+	}
+
+	debug("DRAM: simple test OK\n");
+	return 0;
+}
+
+// Set the Vref mode for the controller
+//
+static void mctl_vrefzq_init(const dram_para_t *para, const dram_config_t *config)
+{
+	if (config->dram_tpr13 & BIT(17))
+		return;
+
+	clrsetbits_le32(0x3103110, 0x7f7f7f7f, para->dram_tpr5);
+
+	// IOCVR1
+	if ((config->dram_tpr13 & BIT(16)) == 0)
+		clrsetbits_le32(0x3103114, 0x7f, para->dram_tpr6 & 0x7f);
+}
+
+// Perform an init of the controller. This is actually done 3 times. The first
+// time to establish the number of ranks and DQ width. The second time to
+// establish the actual ram size. The third time is final one, with the final
+// settings.
+//
+static int mctl_core_init(const dram_para_t *para, const dram_config_t *config)
+{
+	mctl_sys_init(para, config);
+
+	mctl_vrefzq_init(para, config);
+
+	mctl_com_init(para, config);
+
+	mctl_phy_ac_remapping(para, config);
+
+	mctl_set_timing_params(para, config);
+
+	return mctl_channel_init(0, para, config);
+}
+
+/*
+ * This routine sizes a DRAM device by cycling through address lines and
+ * figuring out if they are connected to a real address line, or if the
+ * address is a mirror.
+ * First the column and bank bit allocations are set to low values (2 and 9
+ * address lines). Then a maximum allocation (16 lines) is set for rows and
+ * this is tested.
+ * Next the BA2 line is checked. This seems to be placed above the column,
+ * BA0-1 and row addresses. Finally, the column address is allocated 13 lines
+ * and these are tested. The results are placed in dram_para1 and dram_para2.
+ */
+static int auto_scan_dram_size(const dram_para_t *para, dram_config_t *config)
+{
+	unsigned int rval, i, j, rank, maxrank, offs;
+	unsigned int shft;
+	unsigned long ptr, mc_work_mode, chk;
+
+	if (mctl_core_init(para, config) == 0) {
+		printf("DRAM initialisation error : 0\n");
+		return 0;
+	}
+
+	maxrank	= (config->dram_para2 & 0xf000) ? 2 : 1;
+	mc_work_mode = 0x3102000;
+	offs = 0;
+
+	/* write test pattern */
+	for (i = 0, ptr = CFG_SYS_SDRAM_BASE; i < 64; i++, ptr += 4)
+		writel((i & 0x1) ? ptr : ~ptr, ptr);
+
+	for (rank = 0; rank < maxrank;) {
+		/* set row mode */
+		clrsetbits_le32(mc_work_mode, 0xf0c, 0x6f0);
+		udelay(1);
+
+		// Scan per address line, until address wraps (i.e. see shadow)
+		for (i = 11; i < 17; i++) {
+			chk = CFG_SYS_SDRAM_BASE + (1U << (i + 11));
+			ptr = CFG_SYS_SDRAM_BASE;
+			for (j = 0; j < 64; j++) {
+				if (readl(chk) != ((j & 1) ? ptr : ~ptr))
+					break;
+				ptr += 4;
+				chk += 4;
+			}
+			if (j == 64)
+				break;
+		}
+		if (i > 16)
+			i = 16;
+		debug("rank %d row = %d\n", rank, i);
+
+		/* Store rows in para 1 */
+		shft = offs + 4;
+		rval = config->dram_para1;
+		rval &= ~(0xff << shft);
+		rval |= i << shft;
+		config->dram_para1 = rval;
+
+		if (rank == 1)		/* Set bank mode for rank0 */
+			clrsetbits_le32(0x3102000, 0xffc, 0x6a4);
+
+		/* Set bank mode for current rank */
+		clrsetbits_le32(mc_work_mode, 0xffc, 0x6a4);
+		udelay(1);
+
+		// Test if bit A23 is BA2 or mirror XXX A22?
+		chk = CFG_SYS_SDRAM_BASE + (1U << 22);
+		ptr = CFG_SYS_SDRAM_BASE;
+		for (i = 0, j = 0; i < 64; i++) {
+			if (readl(chk) != ((i & 1) ? ptr : ~ptr)) {
+				j = 1;
+				break;
+			}
+			ptr += 4;
+			chk += 4;
+		}
+
+		debug("rank %d bank = %d\n", rank, (j + 1) << 2); /* 4 or 8 */
+
+		/* Store banks in para 1 */
+		shft = 12 + offs;
+		rval = config->dram_para1;
+		rval &= ~(0xf << shft);
+		rval |= j << shft;
+		config->dram_para1 = rval;
+
+		if (rank == 1)		/* Set page mode for rank0 */
+			clrsetbits_le32(0x3102000, 0xffc, 0xaa0);
+
+		/* Set page mode for current rank */
+		clrsetbits_le32(mc_work_mode, 0xffc, 0xaa0);
+		udelay(1);
+
+		// Scan per address line, until address wraps (i.e. see shadow)
+		for (i = 9; i < 14; i++) {
+			chk = CFG_SYS_SDRAM_BASE + (1U << i);
+			ptr = CFG_SYS_SDRAM_BASE;
+			for (j = 0; j < 64; j++) {
+				if (readl(chk) != ((j & 1) ? ptr : ~ptr))
+					break;
+				ptr += 4;
+				chk += 4;
+			}
+			if (j == 64)
+				break;
+		}
+		if (i > 13)
+			i = 13;
+
+		unsigned int pgsize = (i == 9) ? 0 : (1 << (i - 10));
+		debug("rank %d page size = %d KB\n", rank, pgsize);
+
+		/* Store page size */
+		shft = offs;
+		rval = config->dram_para1;
+		rval &= ~(0xf << shft);
+		rval |= pgsize << shft;
+		config->dram_para1 = rval;
+
+		// Move to next rank
+		rank++;
+		if (rank != maxrank) {
+			if (rank == 1) {
+				/* MC_WORK_MODE */
+				clrsetbits_le32(0x3202000, 0xffc, 0x6f0);
+
+				/* MC_WORK_MODE2 */
+				clrsetbits_le32(0x3202004, 0xffc, 0x6f0);
+			}
+			/* store rank1 config in upper half of para1 */
+			offs += 16;
+			mc_work_mode += 4;	/* move to MC_WORK_MODE2 */
+		}
+	}
+	if (maxrank == 2) {
+		config->dram_para2 &= 0xfffff0ff;
+		/* note: rval is equal to para->dram_para1 here */
+		if ((rval & 0xffff) == (rval >> 16)) {
+			debug("rank1 config same as rank0\n");
+		} else {
+			config->dram_para2 |= BIT(8);
+			debug("rank1 config different from rank0\n");
+		}
+	}
+
+	return 1;
+}
+
+/*
+ * This routine sets up parameters with dqs_gating_mode equal to 1 and two
+ * ranks enabled. It then configures the core and tests for 1 or 2 ranks and
+ * full or half DQ width. It then resets the parameters to the original values.
+ * dram_para2 is updated with the rank and width findings.
+ */
+static int auto_scan_dram_rank_width(const dram_para_t *para,
+				     dram_config_t *config)
+{
+	unsigned int s1 = config->dram_tpr13;
+	unsigned int s2 = config->dram_para1;
+
+	config->dram_para1 = 0x00b000b0;
+	config->dram_para2 = (config->dram_para2 & ~0xf) | BIT(12);
+
+	/* set DQS probe mode */
+	config->dram_tpr13 = (config->dram_tpr13 & ~0x8) | BIT(2) | BIT(0);
+
+	mctl_core_init(para, config);
+
+	if (readl(0x3103010) & BIT(20))
+		return 0;
+
+	if (dqs_gate_detect(config) == 0)
+		return 0;
+
+	config->dram_tpr13 = s1;
+	config->dram_para1 = s2;
+
+	return 1;
+}
+
+/*
+ * This routine determines the SDRAM topology. It first establishes the number
+ * of ranks and the DQ width. Then it scans the SDRAM address lines to establish
+ * the size of each rank. It then updates dram_tpr13 to reflect that the sizes
+ * are now known: a re-init will not repeat the autoscan.
+ */
+static int auto_scan_dram_config(const dram_para_t *para,
+				 dram_config_t *config)
+{
+	if (((config->dram_tpr13 & BIT(14)) == 0) &&
+	    (auto_scan_dram_rank_width(para, config) == 0)) {
+		printf("ERROR: auto scan dram rank & width failed\n");
+		return 0;
+	}
+
+	if (((config->dram_tpr13 & BIT(0)) == 0) &&
+	    (auto_scan_dram_size(para, config) == 0)) {
+		printf("ERROR: auto scan dram size failed\n");
+		return 0;
+	}
+
+	if ((config->dram_tpr13 & BIT(15)) == 0)
+		config->dram_tpr13 |= BIT(14) | BIT(13) | BIT(1) | BIT(0);
+
+	return 1;
+}
+
+static int init_DRAM(int type, const dram_para_t *para)
+{
+	dram_config_t config = {
+		.dram_para1	= 0x000010d2,
+		.dram_para2	= 0,
+		.dram_tpr13	= CONFIG_DRAM_SUNXI_TPR13,
+	};
+	u32 rc, mem_size_mb;
+
+	debug("DRAM BOOT DRIVE INFO: %s\n", "V0.24");
+	debug("DRAM CLK = %d MHz\n", para->dram_clk);
+	debug("DRAM Type = %d (2:DDR2,3:DDR3)\n", para->dram_type);
+	if ((para->dram_odt_en & 0x1) == 0)
+		debug("DRAMC read ODT off\n");
+	else
+		debug("DRAMC ZQ value: 0x%x\n", para->dram_zq);
+
+	/* Test ZQ status */
+	if (config.dram_tpr13 & BIT(16)) {
+		debug("DRAM only have internal ZQ\n");
+		setbits_le32(0x3000160, BIT(8));
+		writel(0, 0x3000168);
+		udelay(10);
+	} else {
+		clrbits_le32(0x3000160, 0x3);
+		writel(config.dram_tpr13 & BIT(16), 0x7010254);
+		udelay(10);
+		clrsetbits_le32(0x3000160, 0x108, BIT(1));
+		udelay(10);
+		setbits_le32(0x3000160, BIT(0));
+		udelay(20);
+		debug("ZQ value = 0x%x\n", readl(0x300016c));
+	}
+
+	dram_voltage_set(para);
+
+	/* Set SDRAM controller auto config */
+	if ((config.dram_tpr13 & BIT(0)) == 0) {
+		if (auto_scan_dram_config(para, &config) == 0) {
+			printf("auto_scan_dram_config() FAILED\n");
+			return 0;
+		}
+	}
+
+	/* report ODT */
+	rc = para->dram_mr1;
+	if ((rc & 0x44) == 0)
+		debug("DRAM ODT off\n");
+	else
+		debug("DRAM ODT value: 0x%x\n", rc);
+
+	/* Init core, final run */
+	if (mctl_core_init(para, &config) == 0) {
+		printf("DRAM initialisation error: 1\n");
+		return 0;
+	}
+
+	/* Get SDRAM size */
+	/* TODO: who ever puts a negative number in the top half? */
+	rc = config.dram_para2;
+	if (rc & BIT(31)) {
+		rc = (rc >> 16) & ~BIT(15);
+	} else {
+		rc = DRAMC_get_dram_size();
+		debug("DRAM: size = %dMB\n", rc);
+		config.dram_para2 = (config.dram_para2 & 0xffffU) | rc << 16;
+	}
+	mem_size_mb = rc;
+
+	/* Purpose ?? */
+	if (config.dram_tpr13 & BIT(30)) {
+		rc = para->dram_tpr8;
+		if (rc == 0)
+			rc = 0x10000200;
+		writel(rc, 0x31030a0);
+		writel(0x40a, 0x310309c);
+		setbits_le32(0x3103004, BIT(0));
+		debug("Enable Auto SR\n");
+	} else {
+		clrbits_le32(0x31030a0, 0xffff);
+		clrbits_le32(0x3103004, 0x1);
+	}
+
+	/* Purpose ?? */
+	if (config.dram_tpr13 & BIT(9)) {
+		clrsetbits_le32(0x3103100, 0xf000, 0x5000);
+	} else {
+		if (para->dram_type != SUNXI_DRAM_TYPE_LPDDR2)
+			clrbits_le32(0x3103100, 0xf000);
+	}
+
+	setbits_le32(0x3103140, BIT(31));
+
+	/* CHECK: is that really writing to a different register? */
+	if (config.dram_tpr13 & BIT(8))
+		writel(readl(0x3103140) | 0x300, 0x31030b8);
+
+	if (config.dram_tpr13 & BIT(16))
+		clrbits_le32(0x3103108, BIT(13));
+	else
+		setbits_le32(0x3103108, BIT(13));
+
+	/* Purpose ?? */
+	if (para->dram_type == SUNXI_DRAM_TYPE_LPDDR3)
+		clrsetbits_le32(0x310307c, 0xf0000, 0x1000);
+
+	dram_enable_all_master();
+	if (config.dram_tpr13 & BIT(28)) {
+		if ((readl(0x70005d4) & BIT(16)) ||
+		    dramc_simple_wr_test(mem_size_mb, 4096))
+			return 0;
+	}
+
+	return mem_size_mb;
+}
+
+	static const dram_para_t para = {
+		.dram_clk	= CONFIG_DRAM_CLK,
+		.dram_type	= CONFIG_SUNXI_DRAM_TYPE,
+		.dram_zq	= CONFIG_DRAM_ZQ,
+		.dram_odt_en	= CONFIG_DRAM_SUNXI_ODT_EN,
+		.dram_mr0	= 0x1c70,
+		.dram_mr1	= 0x42,
+		.dram_mr2	= 0x18,
+		.dram_mr3	= 0,
+		.dram_tpr0	= 0x004a2195,
+		.dram_tpr1	= 0x02423190,
+		.dram_tpr2	= 0x0008b061,
+		.dram_tpr3	= 0xb4787896, // unused
+		.dram_tpr4	= 0,
+		.dram_tpr5	= 0x48484848,
+		.dram_tpr6	= 0x00000048,
+		.dram_tpr7	= 0x1620121e, // unused
+		.dram_tpr8	= 0,
+		.dram_tpr9	= 0, // clock?
+		.dram_tpr10	= 0,
+		.dram_tpr11	= CONFIG_DRAM_SUNXI_TPR11,
+		.dram_tpr12	= CONFIG_DRAM_SUNXI_TPR12,
+	};
+
+unsigned long sunxi_dram_init(void)
+{
+	return init_DRAM(0, &para) * 1024UL * 1024;
+};
+
+#ifdef CONFIG_RAM		/* using the driver model */
+struct sunxi_ram_priv {
+	size_t size;
+};
+
+static int sunxi_ram_probe(struct udevice *dev)
+{
+	struct sunxi_ram_priv *priv = dev_get_priv(dev);
+	unsigned long dram_size;
+
+	debug("%s: %s: probing\n", __func__, dev->name);
+
+	dram_size = sunxi_dram_init();
+	if (!dram_size) {
+		printf("DRAM init failed: %d\n", ret);
+		return -ENODEV;
+	}
+
+	priv->size = dram_size;
+
+	return 0;
+}
+
+static int sunxi_ram_get_info(struct udevice *dev, struct ram_info *info)
+{
+	struct sunxi_ram_priv *priv = dev_get_priv(dev);
+
+	debug("%s: %s: getting info\n", __func__, dev->name);
+
+	info->base = CFG_SYS_SDRAM_BASE;
+	info->size = priv->size;
+
+	return 0;
+}
+
+static struct ram_ops sunxi_ram_ops = {
+	.get_info = sunxi_ram_get_info,
+};
+
+static const struct udevice_id sunxi_ram_ids[] = {
+	{ .compatible = "allwinner,sun20i-d1-mbus" },
+	{ }
+};
+
+U_BOOT_DRIVER(sunxi_ram) = {
+	.name = "sunxi_ram",
+	.id = UCLASS_RAM,
+	.of_match = sunxi_ram_ids,
+	.ops = &sunxi_ram_ops,
+	.probe = sunxi_ram_probe,
+	.priv_auto = sizeof(struct sunxi_ram_priv),
+};
+#endif				/* CONFIG_RAM (using driver model) */
diff --git a/drivers/ram/sunxi/dram_sun20i_d1.h b/drivers/ram/sunxi/dram_sun20i_d1.h
new file mode 100644
index 00000000000..91383f6cf10
--- /dev/null
+++ b/drivers/ram/sunxi/dram_sun20i_d1.h
@@ -0,0 +1,73 @@ 
+// SPDX-License-Identifier:	GPL-2.0+
+/*
+ * D1/R528/T113 DRAM controller register and constant defines
+ *
+ * (C) Copyright 2022 Arm Ltd.
+ * Based on H6 and H616 header, which are:
+ * (C) Copyright 2017  Icenowy Zheng <icenowy@aosc.io>
+ * (C) Copyright 2020  Jernej Skrabec <jernej.skrabec@siol.net>
+ *
+ */
+
+#ifndef _SUNXI_DRAM_SUN20I_D1_H
+#define _SUNXI_DRAM_SUN20I_D1_H
+
+enum sunxi_dram_type {
+	SUNXI_DRAM_TYPE_DDR2 = 2,
+	SUNXI_DRAM_TYPE_DDR3 = 3,
+	SUNXI_DRAM_TYPE_LPDDR2 = 6,
+	SUNXI_DRAM_TYPE_LPDDR3 = 7,
+};
+
+/*
+ * This structure contains a mixture of fixed configuration settings,
+ * variables that are used at runtime to communicate settings between
+ * different stages and functions, and unused values.
+ * This is copied from Allwinner's boot0 data structure, which can be
+ * found at offset 0x38 in any boot0 binary. To allow matching up some
+ * board specific settings, this struct is kept compatible, even though
+ * we don't need all members in our code.
+ */
+typedef struct dram_para {
+	/* normal configuration */
+	const u32	dram_clk;
+	const u32	dram_type;
+	const u32	dram_zq;
+	const u32	dram_odt_en;
+
+	/* timing configuration */
+	const u32	dram_mr0;
+	const u32	dram_mr1;
+	const u32	dram_mr2;
+	const u32	dram_mr3;
+	const u32	dram_tpr0;	//DRAMTMG0
+	const u32	dram_tpr1;	//DRAMTMG1
+	const u32	dram_tpr2;	//DRAMTMG2
+	const u32	dram_tpr3;	//DRAMTMG3
+	const u32	dram_tpr4;	//DRAMTMG4
+	const u32	dram_tpr5;	//DRAMTMG5
+	const u32	dram_tpr6;	//DRAMTMG8
+	const u32	dram_tpr7;
+	const u32	dram_tpr8;
+	const u32	dram_tpr9;
+	const u32	dram_tpr10;
+	const u32	dram_tpr11;
+	const u32	dram_tpr12;
+} dram_para_t;
+
+typedef struct dram_config {
+	/* control configuration */
+	u32	dram_para1;
+	u32	dram_para2;
+	/* contains a bitfield of DRAM setup settings */
+	u32	dram_tpr13;
+} dram_config_t;
+
+static inline int ns_to_t(int nanoseconds)
+{
+	const unsigned int ctrl_freq = CONFIG_DRAM_CLK / 2;
+
+	return DIV_ROUND_UP(ctrl_freq * nanoseconds, 1000);
+}
+
+#endif /* _SUNXI_DRAM_SUN20I_D1_H */