Re: [PATCH 4/9] mvebu: ddr: Rename CONFIG_DDR_FIXED_SIZE to CONFIG_SYS_SDRAM_SIZE

Stefan Roese
2021-09-01T14:33:10Z

On 01.09.21 13:29, Tom Rini wrote:
> On Wed, Sep 01, 2021 at 07:27:54AM +0200, Stefan Roese wrote:
>> Hi Tom,
>>
>> On 31.08.21 14:43, Tom Rini wrote:
>>> On Tue, Aug 31, 2021 at 07:51:29AM +0200, Stefan Roese wrote:
>>>> Hi Tom,
>>>>
>>>> On 21.08.21 19:50, Tom Rini wrote:
>>>>> We have a number of CONFIG symbols to express the fixed size of system
>>>>> memory. For now, rename CONFIG_DDR_FIXED_SIZE to CONFIG_SYS_SDRAM_SIZE
>>>>> and adjust usage to match that CONFIG_SYS_SDRAM_SIZE expects the entire
>>>>> size rather than MiB.
>>>>>
>>>>> Cc: Marek Behún <marek.behun@nic.cz>
>>>>> Cc: Stefan Roese <sr@denx.de>
>>>>> Signed-off-by: Tom Rini <trini@konsulko.com>
>>>>> ---
>>>>> drivers/ddr/marvell/axp/ddr3_axp.h | 4 ++--
>>>>> include/configs/maxbcm.h | 4 +++-
>>>>> include/configs/theadorable.h | 4 +++-
>>>>> 3 files changed, 8 insertions(+), 4 deletions(-)
>>>>>
>>>>> diff --git a/drivers/ddr/marvell/axp/ddr3_axp.h b/drivers/ddr/marvell/axp/ddr3_axp.h
>>>>> index 270691e9bcd3..970651f87029 100644
>>>>> --- a/drivers/ddr/marvell/axp/ddr3_axp.h
>>>>> +++ b/drivers/ddr/marvell/axp/ddr3_axp.h
>>>>> @@ -19,10 +19,10 @@
>>>>> #define FAR_END_DIMM_ADDR 0x50
>>>>> #define MAX_DIMM_ADDR 0x60
>>>>> -#ifndef CONFIG_DDR_FIXED_SIZE
>>>>> +#ifndef CONFIG_SYS_SDRAM_SIZE
>>>>> #define SDRAM_CS_SIZE 0xFFFFFFF
>>>>> #else
>>>>> -#define SDRAM_CS_SIZE (CONFIG_DDR_FIXED_SIZE - 1)
>>>>> +#define SDRAM_CS_SIZE ((CONFIG_SYS_SDRAM_SIZE >> 10) - 1)
>>>>
>>>> Why are you using ">> 10" (dividing by 1024) here?
>>>>
>>>> Thanks,
>>>> Stefan
>>>>
>>>>> #endif
>>>>> #define SDRAM_CS_BASE 0x0
>>>>> #define SDRAM_DIMM_SIZE 0x80000000
>>>>> diff --git a/include/configs/maxbcm.h b/include/configs/maxbcm.h
>>>>> index fc2393204bec..5098f12f5425 100644
>>>>> --- a/include/configs/maxbcm.h
>>>>> +++ b/include/configs/maxbcm.h
>>>>> @@ -6,6 +6,8 @@
>>>>> #ifndef _CONFIG_DB_MV7846MP_GP_H
>>>>> #define _CONFIG_DB_MV7846MP_GP_H
>>>>> +#include <linux/sizes.h>
>>>>> +
>>>>> /*
>>>>> * High Level Configuration Options (easy to change)
>>>>> */
>>>>> @@ -65,7 +67,7 @@
>>>>> /* SPL related SPI defines */
>>>>> /* Enable DDR support in SPL (DDR3 training from Marvell bin_hdr) */
>>>>> -#define CONFIG_DDR_FIXED_SIZE (1 << 20) /* 1GiB */
>>>>> +#define CONFIG_SYS_SDRAM_SIZE SZ_1G
>>>
>>> OK, so before my change, SDRAM_CS_SIZE = 0xfffff. After my change,
>>> SDRAM_CS_SIZE = 0xfffff, still.
>>>
>>>>> #define CONFIG_BOARD_ECC_SUPPORT /* this board supports ECC */
>>>>> #endif /* _CONFIG_DB_MV7846MP_GP_H */
>>>>> diff --git a/include/configs/theadorable.h b/include/configs/theadorable.h
>>>>> index 760713d3ef87..abc48ff44ca5 100644
>>>>> --- a/include/configs/theadorable.h
>>>>> +++ b/include/configs/theadorable.h
>>>>> @@ -6,6 +6,8 @@
>>>>> #ifndef _CONFIG_THEADORABLE_H
>>>>> #define _CONFIG_THEADORABLE_H
>>>>> +#include <linux/sizes.h>
>>>>> +
>>>>> /*
>>>>> * High Level Configuration Options (easy to change)
>>>>> */
>>>>> @@ -93,6 +95,6 @@
>>>>> #define CONFIG_SPL_BOOTROM_SAVE (CONFIG_SPL_STACK + 4)
>>>>> /* Enable DDR support in SPL (DDR3 training from Marvell bin_hdr) */
>>>>> -#define CONFIG_DDR_FIXED_SIZE (2 << 20) /* 2GiB */
>>>>> +#define CONFIG_SYS_SDRAM_SIZE SZ_2G
>>>
>>> Here, before SDRAM_CS_SIZE = 0x1fffff and then after SDRAM_CS_SIZE =
>>> 0x1fffff.
>>>
>>> This is because CONFIG_DDR_FIXED_SIZE is kilobytes and
>>> CONFIG_SYS_SDRAM_SIZE is bytes, yes? Thanks.
>>
>> Only if CONFIG_DDR_FIXED_SIZE / CONFIG_SYS_SDRAM_SIZE is undefined.
>>
>> Please see e.g. theadorable.h above. Here we have:
>>
>> #define CONFIG_DDR_FIXED_SIZE (2 << 20) /* 2GiB */
>>
>> With this, the following will happen in ddr3_axp.h:
>>
>> #ifndef CONFIG_DDR_FIXED_SIZE
>> #define SDRAM_CS_SIZE 0xFFFFFFF
>> #else
>> #define SDRAM_CS_SIZE (CONFIG_DDR_FIXED_SIZE - 1)
>> #endif
>>
>> So SDRAM_CS_SIZE will be set to "(2 << 20) - 1".
>>
>> AFAICT, on Armada XP CONFIG_DDR_FIXED_SIZE is bytes and not
>> kilobytes.
>
> I'm not follow, sorry. There's exactly two defines of
> CONFIG_DDR_FIXED_SIZE before this patch, neither platform also set
> CONFIG_SYS_SDRAM_SIZE, and they're converted to CONFIG_SYS_SDRAM_SIZE
> now. I did the evaluations to confirm the code is unchanged.

Ah, now I see my misunderstanding. "2 << 20" is of course 2MiB and
not 2GiB. I was mislead by the comment in the header.

But now I'm thinking that SDRAM_CS_SIZE might need to be set to the
CS size in bytes and *not* in kilobytes for Armada XP. But this is a
different issue which I need to investigate and perhaps follow up on.

Thanks,
Stefan