Hello Joacim,
On 28.10.21 10:46, Joacim Zetterling wrote:
> The imx8mn has a 16-bit SDRAM bus width access but the calculation
> of the memory size treat it as a 32-bit width bus which makes the
> memory calculation to be wrong (meminfo wrong and memtest fails).
I missed this because of the /memory node in the device tree filling
up the remainder. I removed /memory and tried your patch on an
i.MX8MN DDR EVK, but it doesn't change iomem output:
0x0000000040000000 - 0x000000007fffffff (size 0x0000000040000000) ram0
The 8MN DDR4 EVK reports FIELD_GET(DDRC_MSTR_DEVICE_CONFIG, mstr) == 0b10
and FIELD_GET(DDRC_MSTR_DATA_BUS_WIDTH, mstr) == 0b00.
> There is a difference between the imx7 and the imx8 familys.
> The imx8 family has a device config field in the master register of
> the DDRC controller which the imx7 family doesn't have (the bus width
> is 32-bit as default).
>
> The device config field together with the DQ configuration tells us
> the actual bus width of the device for a correct mem size calculaton.
>
> From the imx8mn reference manual:
> +----------------------------------------------------+
> | Field | Function |
> |----------------------------------------------------|
> | 31-30 | Indicates the configuration of the |
> | | device used in the system. |
> | device_config | 00b - x4 device |
> | | 01b - x8 device |
> | | 10b - x16 device |
> | | 11b - x32 device |
> +----------------------------------------------------+
> ...
> ...
>
> Tested on the IMX8MN Evk with 2GB DDR4 and on a IMX8MN custom board
> with 2GB LPDDR4, checked size and made memory test.
What's the device_config for each?
> Signed-off-by: Joacim Zetterling <joacim.zetterling@xxxxxxxxxxxx>
> ---
> arch/arm/mach-imx/esdctl.c | 16 +++++++++++-----
> 1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm/mach-imx/esdctl.c b/arch/arm/mach-imx/esdctl.c
> index e56da3cb76d4..f80d94f2fca0 100644
> --- a/arch/arm/mach-imx/esdctl.c
> +++ b/arch/arm/mach-imx/esdctl.c
> @@ -320,6 +320,7 @@ static int vf610_ddrmc_add_mem(void *mmdcbase, struct imx_esdctl_data *data)
> #define DDRC_MSTR_LPDDR4 BIT(5)
> #define DDRC_MSTR_DATA_BUS_WIDTH GENMASK(13, 12)
> #define DDRC_MSTR_ACTIVE_RANKS GENMASK(27, 24)
> +#define DDRC_MSTR_DEVICE_CONFIG GENMASK(31, 30)
>
> #define DDRC_ADDRMAP0_CS_BIT1 GENMASK(12, 8)
>
> @@ -361,7 +362,7 @@ static resource_size_t
> imx_ddrc_sdram_size(void __iomem *ddrc, const u32 addrmap[],
> u8 col_max, const u8 col_b[], unsigned int col_b_num,
> u8 row_max, const u8 row_b[], unsigned int row_b_num,
> - bool reduced_adress_space)
> + bool reduced_adress_space, bool is_imx8)
> {
> const u32 mstr = readl(ddrc + DDRC_MSTR);
> unsigned int banks, ranks, columns, rows, active_ranks, width;
> @@ -384,15 +385,20 @@ imx_ddrc_sdram_size(void __iomem *ddrc, const u32 addrmap[],
> BUG();
> }
>
> + if (is_imx8)
> + width = (1 << FIELD_GET(DDRC_MSTR_DEVICE_CONFIG, mstr)) >> 1;
for device_config == 0, size should be halved, but instead you would get a
width of zero here.
> + else
> + width = 4;
> +
> switch (FIELD_GET(DDRC_MSTR_DATA_BUS_WIDTH, mstr)) {
> case 0b00: /* Full DQ bus */
> width = 4;
I can't really follow. Shouldn't this be dropped to take the
value of width above?
> break;
> case 0b01: /* Half DQ bus */
> - width = 2;
> + width >>= 1;
> break;
> case 0b10: /* Quarter DQ bus */
> - width = 1;
> + width >>= 2;
> break;
> default:
> BUG();
> @@ -466,7 +472,7 @@ static resource_size_t imx8m_ddrc_sdram_size(void __iomem *ddrc)
> return imx_ddrc_sdram_size(ddrc, addrmap,
> 12, ARRAY_AND_SIZE(col_b),
> 16, ARRAY_AND_SIZE(row_b),
> - reduced_adress_space);
> + reduced_adress_space, true);
> }
>
> static int imx8m_ddrc_add_mem(void *mmdcbase, struct imx_esdctl_data *data)
> @@ -508,7 +514,7 @@ static resource_size_t imx7d_ddrc_sdram_size(void __iomem *ddrc)
> return imx_ddrc_sdram_size(ddrc, addrmap,
> 11, ARRAY_AND_SIZE(col_b),
> 15, ARRAY_AND_SIZE(row_b),
> - reduced_adress_space);
> + reduced_adress_space, false);
> }
>
> static int imx7d_ddrc_add_mem(void *mmdcbase, struct imx_esdctl_data *data)
>
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
_______________________________________________
barebox mailing list
barebox@xxxxxxxxxxxxxxxxxxx
http://lists.infradead.org/mailman/listinfo/barebox
