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

[Jagan Teki]

On Fri, Oct 26, 2018 at 11:27 AM Icenowy Zheng <icenowy at aosc.io> wrote:
>
>
>
> 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.

Applied to u-boot-sunxi/master