[U-Boot] [PATCH 13/22] x86: fsp: Save stack address to CMOS for next S3 boot

[Simon Glass]

Hi Bin,

On 16 March 2017 at 08:26, Bin Meng <bmeng.cn at gmail.com> wrote:
> At the end of pre-relocation phase, save the new stack address
> to CMOS and use it as the stack on next S3 boot for fsp_init()
> continuation function.
>
> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
> ---
>
>  arch/x86/cpu/cpu.c                 |  8 ++++++++
>  arch/x86/include/asm/cmos_layout.h | 31 +++++++++++++++++++++++++++++++
>  arch/x86/include/asm/u-boot-x86.h  |  1 +
>  arch/x86/lib/fsp/fsp_common.c      | 30 +++++++++++++++++++++++++++++-
>  4 files changed, 69 insertions(+), 1 deletion(-)
>  create mode 100644 arch/x86/include/asm/cmos_layout.h

Reviewed-by: Simon Glass <sjg at chromium.org>

nits below

>
> diff --git a/arch/x86/cpu/cpu.c b/arch/x86/cpu/cpu.c
> index afc8645..9e2aee2 100644
> --- a/arch/x86/cpu/cpu.c
> +++ b/arch/x86/cpu/cpu.c
> @@ -278,6 +278,14 @@ int reserve_arch(void)
>         high_table_reserve();
>  #endif
>
> +#if defined(CONFIG_HAVE_ACPI_RESUME) && defined(CONFIG_HAVE_FSP)
> +       /*
> +        * Save stack address to CMOS so that at next S3 boot,
> +        * we can use it as the stack address for fsp_contiue()
> +        */
> +       fsp_save_s3_stack();
> +#endif
> +
>         return 0;
>  }
>  #endif
> diff --git a/arch/x86/include/asm/cmos_layout.h b/arch/x86/include/asm/cmos_layout.h
> new file mode 100644
> index 0000000..0a0a51e
> --- /dev/null
> +++ b/arch/x86/include/asm/cmos_layout.h
> @@ -0,0 +1,31 @@
> +/*
> + * Copyright (C) 2017, Bin Meng <bmeng.cn at gmail.com>
> + *
> + * SPDX-License-Identifier:    GPL-2.0+
> + */
> +
> +#ifndef __CMOS_LAYOUT_H
> +#define __CMOS_LAYOUT_H
> +
> +/*
> + * The RTC internal registers and RAM is organized as two banks of 128 bytes
> + * each, called the standard and extended banks. The first 14 bytes of the
> + * standard bank contain the RTC time and date information along with four
> + * registers, A - D, that are used for configuration of the RTC. The extended
> + * bank contains a full 128 bytes of battery backed SRAM.
> + *
> + * For simplicity in U-Boot we only support CMOS in the standard bank, and
> + * its base address starts from offset 0x10, which leaves us 112 bytes space.
> + */
> +#define CMOS_BASE              0x10
> +
> +/*
> + * The file records all offsets off CMOS_BASE that is currently used by
> + * U-Boot for various reasons. It is put in such a unified place in order
> + * to be consistent across platforms.
> + */
> +
> +/* stack address for S3 boot in a FSP configuration, 4 bytes */
> +#define CMOS_FSP_STACK_ADDR    CMOS_BASE
> +
> +#endif /* __CMOS_LAYOUT_H */
> diff --git a/arch/x86/include/asm/u-boot-x86.h b/arch/x86/include/asm/u-boot-x86.h
> index 4f901f9..024aaf4 100644
> --- a/arch/x86/include/asm/u-boot-x86.h
> +++ b/arch/x86/include/asm/u-boot-x86.h
> @@ -56,6 +56,7 @@ u32 isa_map_rom(u32 bus_addr, int size);
>  int video_bios_init(void);
>
>  /* arch/x86/lib/fsp/... */
> +int fsp_save_s3_stack(void);
>  int x86_fsp_init(void);

Function comment?

>
>  void   board_init_f_r_trampoline(ulong) __attribute__ ((noreturn));
> diff --git a/arch/x86/lib/fsp/fsp_common.c b/arch/x86/lib/fsp/fsp_common.c
> index 2b33fba..df73a2a 100644
> --- a/arch/x86/lib/fsp/fsp_common.c
> +++ b/arch/x86/lib/fsp/fsp_common.c
> @@ -5,8 +5,12 @@
>   */
>
>  #include <common.h>
> +#include <dm.h>
>  #include <errno.h>
> +#include <rtc.h>
>  #include <asm/acpi_s3.h>
> +#include <asm/cmos_layout.h>
> +#include <asm/early_cmos.h>
>  #include <asm/io.h>
>  #include <asm/mrccache.h>
>  #include <asm/post.h>
> @@ -71,9 +75,32 @@ static __maybe_unused void *fsp_prepare_mrc_cache(void)
>         return cache->data;
>  }
>
> +#ifdef CONFIG_HAVE_ACPI_RESUME
> +int fsp_save_s3_stack(void)
> +{
> +       struct udevice *dev;
> +       int ret;
> +
> +       if (gd->arch.prev_sleep_state == ACPI_S3)
> +               return 0;
> +
> +       ret = uclass_get_device(UCLASS_RTC, 0, &dev);

You need to use uclass_get_device_err() to get an error I think.

> +       if (ret) {
> +               debug("Cannot find RTC: err=%d\n", ret);
> +               return -ENODEV;
> +       }
> +
> +       /* Save the stack address to CMOS */
> +       rtc_write32(dev, CMOS_FSP_STACK_ADDR, gd->start_addr_sp);

Check error?

> +
> +       return 0;
> +}
> +#endif
> +
>  int x86_fsp_init(void)
>  {
>         void *nvs;
> +       int stack = CONFIG_FSP_TEMP_RAM_ADDR;
>         int boot_mode = BOOT_FULL_CONFIG;
>  #ifdef CONFIG_HAVE_ACPI_RESUME
>         int prev_sleep_state = chipset_prev_sleep_state();
> @@ -102,6 +129,7 @@ int x86_fsp_init(void)
>                                 panic("Reboot System");
>                         }
>
> +                       stack = cmos_read32(CMOS_FSP_STACK_ADDR);

Perhaps you should comment why you are using this instead of rtc_...() ?

>                         boot_mode = BOOT_ON_S3_RESUME;
>                 }
>  #endif
> @@ -110,7 +138,7 @@ int x86_fsp_init(void)
>                  * Note the execution does not return to this function,
>                  * instead it jumps to fsp_continue().
>                  */
> -               fsp_init(CONFIG_FSP_TEMP_RAM_ADDR, boot_mode, nvs);
> +               fsp_init(stack, boot_mode, nvs);
>         } else {
>                 /*
>                  * The second time we enter here, adjust the size of malloc()
> --
> 2.9.2
>

Regards,
Simon