[U-Boot] [PATCH v9 6/9] x86: slimbootloader: Set TSC information for tsc_timer

[Andy Shevchenko]

On Sat, Aug 3, 2019 at 11:30 AM Park, Aiden <aiden.park at intel.com> wrote:
>
> Slim Bootloader already calibrated TSC and provides it to U-Boot.
> Therefore, U-Boot does not have to re-calibrate TSC.
> Configuring tsc_base and clock_rate makes x86 tsc_timer driver bypass
> TSC calibration and use the provided TSC frequency.
> - Get TSC frequency from performance info hob
> - Set tsc_base and clock_rate for tsc_timer driver
>

I'm not convinced with this approach (no tag from me), but I'm not
going to block it.
So, if Bin takes it. I'm fine.

> Signed-off-by: Aiden Park <aiden.park at intel.com>
> Reviewed-by: Bin Meng <bmeng.cn at gmail.com>
> ---
> Changes in v6:
>   * Use EFI_GUID
>   * Add more comments while setting tsc_base and clock_rate
>   * Apply code-review comments
>
> Changes in v3:
>   * Use HOB function from the common HOB library
>
>  arch/x86/cpu/slimbootloader/slimbootloader.c  | 37 +++++++++++++++++++
>  .../asm/arch-slimbootloader/slimbootloader.h  | 28 ++++++++++++++
>  2 files changed, 65 insertions(+)
>
> diff --git a/arch/x86/cpu/slimbootloader/slimbootloader.c b/arch/x86/cpu/slimbootloader/slimbootloader.c
> index 9f3a61ec61..e6b174ca88 100644
> --- a/arch/x86/cpu/slimbootloader/slimbootloader.c
> +++ b/arch/x86/cpu/slimbootloader/slimbootloader.c
> @@ -4,9 +4,46 @@
>   */
>
>  #include <common.h>
> +#include <asm/arch/slimbootloader.h>
> +
> +DECLARE_GLOBAL_DATA_PTR;
> +
> +/**
> + * This sets tsc_base and clock_rate for early_timer and tsc_timer.
> + * The performance info guid hob has all performance timestamp data, but
> + * the only tsc frequency info is used for the timer driver for now.
> + *
> + * Slim Bootloader already calibrated TSC and provides it to U-Boot.
> + * Therefore, U-Boot does not have to re-calibrate TSC.
> + * Configuring tsc_base and clock_rate here makes x86 tsc_timer driver
> + * bypass TSC calibration and use the provided TSC frequency.
> + */
> +static void tsc_init(void)
> +{
> +       struct sbl_performance_info *data;
> +       const efi_guid_t guid = SBL_PERFORMANCE_INFO_GUID;
> +
> +       if (!gd->arch.hob_list)
> +               panic("hob list not found!");
> +
> +       gd->arch.tsc_base = rdtsc();
> +       debug("tsc_base=0x%llx\n", gd->arch.tsc_base);
> +
> +       data = hob_get_guid_hob_data(gd->arch.hob_list, NULL, &guid);
> +       if (!data) {
> +               debug("performance info hob not found\n");
> +               return;
> +       }
> +
> +       /* frequency is in KHz, so to Hz */
> +       gd->arch.clock_rate = data->frequency * 1000;
> +       debug("freq=0x%lx\n", gd->arch.clock_rate);
> +}
>
>  int arch_cpu_init(void)
>  {
> +       tsc_init();
> +
>         return x86_cpu_init_f();
>  }
>
> diff --git a/arch/x86/include/asm/arch-slimbootloader/slimbootloader.h b/arch/x86/include/asm/arch-slimbootloader/slimbootloader.h
> index 174a341d32..05dd1b2b44 100644
> --- a/arch/x86/include/asm/arch-slimbootloader/slimbootloader.h
> +++ b/arch/x86/include/asm/arch-slimbootloader/slimbootloader.h
> @@ -23,6 +23,13 @@
>         EFI_GUID(0x6c6872fe, 0x56a9, 0x4403, \
>                 0xbb, 0x98, 0x95, 0x8d, 0x62, 0xde, 0x87, 0xf1)
>
> +/**
> + * A GUID to get boot performance info hob which is provided by Slim Bootloader
> + */
> +#define SBL_PERFORMANCE_INFO_GUID \
> +       EFI_GUID(0x868204be, 0x23d0, 0x4ff9, \
> +               0xac, 0x34, 0xb9, 0x95, 0xac, 0x04, 0xb1, 0xb9)
> +
>  /**
>   * A single entry of memory map information
>   *
> @@ -84,4 +91,25 @@ struct sbl_serial_port_info {
>         u32     rsvd1;
>  };
>
> +/**
> + * This includes timestamp data which has been collected in Slim Bootloader
> + * stages from the reset vector. In addition, this has TSC frequency in KHz to
> + * calculate each timestamp.
> + *
> + * @rev   : revision of performance_info structure. currently 1.
> + * @rsvd  : padding for alignment
> + * @count : the number of collected timestamp data
> + * @flags : only used in Slim Bootloader
> + * @frequency: tsc frequency in KHz
> + * @timestamp: the array of timestamp data which has 64-bit tsc value
> + */
> +struct sbl_performance_info {
> +       u8      rev;
> +       u8      rsvd[3];
> +       u16     count;
> +       u16     flags;
> +       u32     frequency;
> +       u64     timestamp[0];
> +};
> +
>  #endif /* __SLIMBOOTLOADER_ARCH_H__ */
> --
> 2.20.1
>


-- 
With Best Regards,
Andy Shevchenko