On Sat, Aug 3, 2019 at 11:30 AM Park, Aiden aiden.park@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@intel.com Reviewed-by: Bin Meng bmeng.cn@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