[U-Boot] [linux-sunxi] [PATCH v2 6/6] sunxi: store DRAM size in SPL header

[Icenowy Zheng]

于 2018年10月26日 GMT+08:00 下午1:54:44, Jagan Teki <jagan at amarulasolutions.com> 写到:
>On Thu, Oct 25, 2018 at 2:53 PM Icenowy Zheng <icenowy at aosc.io> wrote:
>>
>> From: Andre Przywara <andre.przywara at arm.com>
>>
>> At the moment we rely on the infamous get_ram_size() function to
>learn
>> the actual DRAM size in U-Boot proper. This function has two issues:
>> 1) It only works if the DRAM size is a power of two. We start to see
>> boards which have 3GB of (usable) DRAM, so this does not fit anymore.
>> 2) As U-Boot has no notion of reserved memory so far, it will happily
>> ride through the DRAM, possibly stepping on secure-only memory. This
>> could be a region of DRAM reserved for OP-TEE or some other secure
>> payload, for instance. It will most likely crash in that case.
>>
>> As the SPL DRAM init routine has very accurate knowledge of the
>actual
>> DRAM size, lets propagate this wisdom to U-Boot proper.
>> We re-purpose a currently reserved word in our SPL header for that.
>> The SPL itself stores the detected DRAM size there, and bumps the SPL
>> header version number in that case. U-Boot proper checks for a valid
>> SPL header and a high enough version number, then uses the DRAM size
>> from there. If the SPL header field is not sufficient, we fall back
>to
>> the old DRAM scanning routine.
>>
>> Part of the DRAM might be present and probed by SPL, but not
>accessible
>> by the CPU. They're restricted in the main U-Boot binary, when
>accessing
>> the DRAM size from SPL header.
>>
>> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
>> Signed-off-by: Icenowy Zheng <icenowy at aosc.io>
>> ---
>> Changes in v2:
>> - Restrict the DRAM size to the accessible range.
>>
>>  arch/arm/include/asm/arch-sunxi/spl.h |  3 ++-
>>  board/sunxi/board.c                   | 28
>++++++++++++++++++++++++++-
>>  2 files changed, 29 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm/include/asm/arch-sunxi/spl.h
>b/arch/arm/include/asm/arch-sunxi/spl.h
>> index 014184b638..4baba38b00 100644
>> --- a/arch/arm/include/asm/arch-sunxi/spl.h
>> +++ b/arch/arm/include/asm/arch-sunxi/spl.h
>> @@ -19,6 +19,7 @@
>>
>>  #define SPL_ENV_HEADER_VERSION SPL_VERSION(0, 1)
>>  #define SPL_DT_HEADER_VERSION  SPL_VERSION(0, 2)
>> +#define SPL_DRAM_HEADER_VERSION        SPL_VERSION(0, 3)
>>
>>  #define SPL_ADDR               CONFIG_SUNXI_SRAM_ADDRESS
>>
>> @@ -70,7 +71,7 @@ struct boot_file_head {
>>          * to the users.
>>          */
>>         uint32_t dt_name_offset;        /* since v0.2, set by
>mksunxiboot */
>> -       uint32_t reserved1;
>> +       uint32_t dram_size;             /* in MiB, since v0.3, set by
>SPL */
>>         uint32_t boot_media;            /* written here by the boot
>ROM */
>>         /* A padding area (may be used for storing text strings) */
>>         uint32_t string_pool[13];       /* since v0.2, filled by
>mksunxiboot */
>> diff --git a/board/sunxi/board.c b/board/sunxi/board.c
>> index bdec82b065..65ae0c4219 100644
>> --- a/board/sunxi/board.c
>> +++ b/board/sunxi/board.c
>> @@ -281,7 +281,16 @@ static struct boot_file_head *
>get_spl_header(uint8_t req_version)
>>
>>  int dram_init(void)
>>  {
>> -       gd->ram_size = get_ram_size((long *)PHYS_SDRAM_0,
>PHYS_SDRAM_0_SIZE);
>> +       struct boot_file_head *spl =
>get_spl_header(SPL_DRAM_HEADER_VERSION);
>> +
>> +       if (spl == INVALID_SPL_HEADER)
>> +               gd->ram_size = get_ram_size((long *)PHYS_SDRAM_0,
>> +                                           PHYS_SDRAM_0_SIZE);
>> +       else
>> +               gd->ram_size = (phys_addr_t)spl->dram_size << 20;
>
>How about checking SPL_DRAM_HEADER_VERSION in valid header case?

get_spl_header() does the version check.