[U-Boot] [PATCH 14/25] x86: Support Intel FSP initialization path in start.S

[Simon Glass]

Hi Bin,

On 4 December 2014 at 08:02, Bin Meng <bmeng.cn at gmail.com> wrote:
> Per Intel FSP architecture specification, FSP provides 3 routines
> for bootloader to call. The first one is the TempRamInit (aka
> Cache-As-Ram initialization) and the second one is the FspInit
> which does the memory bring up (like MRC for other x86 targets)
> and chipset initialization. Those two routines have to be called
> before U-Boot jumping to board_init_f in start.S.
>
> The FspInit() will return several memory blocks called Hand Off
> Blocks (HOBs) whose format is described in Platform Initialization
> (PI) specification (part of the UEFI specication) to the bootloader.
> Save this HOB address to the U-Boot global data for later use.
>
> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
> ---
>  arch/x86/cpu/start.S               | 37 +++++++++++++++++++++++++++++++++++++
>  arch/x86/include/asm/global_data.h |  3 +++
>  arch/x86/lib/asm-offsets.c         |  3 +++
>  3 files changed, 43 insertions(+)
>
> diff --git a/arch/x86/cpu/start.S b/arch/x86/cpu/start.S
> index f9662fb..b4a69d2 100644
> --- a/arch/x86/cpu/start.S
> +++ b/arch/x86/cpu/start.S
> @@ -75,6 +75,35 @@ early_board_init_ret:
>         jmp     car_init
>  .globl car_init_ret
>  car_init_ret:
> +#ifdef CONFIG_HAVE_FSP

Can we put this code into car_init?

> +       /*
> +        * The FSP TempRamInit initializes the ecx and edx registers to
> +        * point to a temporary but writable memory range (Cache-As-RAM).
> +        * ecx: the start of this temporary memory range,
> +        * edx: the end of this range.
> +        */
> +
> +       /* stack grows down from top of CAR */
> +       movl    %edx, %esp
> +
> +       movl    $CONFIG_FSP_TEMP_RAM_ADDR, %eax
> +       xorl    %edx, %edx
> +       xorl    %ecx, %ecx
> +       call    FspInitWrapper

What does this return? Can you add a a comment?

> +
> +.global fsp_init_done
> +fsp_init_done:
> +       /*
> +        * We come here from FspInit with eax pointing to the HOB list.
> +        * Save eax to esi temporarily.
> +        */
> +       movl    %eax, %esi
> +       /*
> +        * Re-initialize the ebp (BIST) to zero, as we already reach here
> +        * which means we passed BIST testing before.

How do you know we already reached here?

> +        */
> +       xorl    %ebp, %ebp
> +#else
>         /*
>          * We now have CONFIG_SYS_CAR_SIZE bytes of Cache-As-RAM (or SRAM,
>          * or fully initialised SDRAM - we really don't care which)
> @@ -95,6 +124,7 @@ car_init_ret:
>  #ifdef CONFIG_DCACHE_RAM_MRC_VAR_SIZE
>         subl    $CONFIG_DCACHE_RAM_MRC_VAR_SIZE, %esp
>  #endif
> +#endif
>
>         /* Reserve space on stack for global data */
>         subl    $GENERATED_GBL_DATA_SIZE, %esp
> @@ -109,6 +139,13 @@ car_init_ret:
>         movl    %esp, %edi
>         rep     stosb
>
> +#ifdef CONFIG_HAVE_FSP
> +       /* Store HOB list */
> +       movl    %esp, %edx
> +       addl    $GD_HOB_LIST, %edx
> +       movl    %esi, (%edx)
> +#endif
> +
>         /* Setup first parameter to setup_gdt, pointer to global_data */
>         movl    %esp, %eax
>
> diff --git a/arch/x86/include/asm/global_data.h b/arch/x86/include/asm/global_data.h
> index 48bbd1a..03d491a 100644
> --- a/arch/x86/include/asm/global_data.h
> +++ b/arch/x86/include/asm/global_data.h
> @@ -47,6 +47,9 @@ struct arch_global_data {
>         enum pei_boot_mode_t pei_boot_mode;
>         const struct pch_gpio_map *gpio_map;    /* board GPIO map */
>         struct memory_info meminfo;     /* Memory information */
> +#ifdef CONFIG_HAVE_FSP
> +       void    *hob_list;              /* FSP HOB list */
> +#endif
>  };
>
>  #endif
> diff --git a/arch/x86/lib/asm-offsets.c b/arch/x86/lib/asm-offsets.c
> index 50a488f..70ccf1b 100644
> --- a/arch/x86/lib/asm-offsets.c
> +++ b/arch/x86/lib/asm-offsets.c
> @@ -18,5 +18,8 @@
>  int main(void)
>  {
>         DEFINE(GD_BIST, offsetof(gd_t, arch.bist));
> +#ifdef CONFIG_HAVE_FSP
> +       DEFINE(GD_HOB_LIST, offsetof(gd_t, arch.hob_list));
> +#endif
>         return 0;
>  }
> --
> 1.8.2.1
>

Regards,
Simon