platform/x86/amd: pmc: Clear metrics table at start of cycle

From: Mario Limonciello <[email protected]>

The area of memory that contains the metrics table may contain garbage when the cycle starts. This normally doesn't matter because the cycle itself will populate it with valid data, however commit 9f5595d5f03fd ("platform/x86/amd: pmc: Require at least 2.5 seconds between HW sleep cycles") started to use it during the check() phase. Depending upon what garbage is in the table it's possible that the system will wait 2.5 seconds for even the first cycle, which will be visible to a user.

To prevent this from happening explicitly clear the table when logging is started.

---
 drivers/platform/x86/amd/pmc/pmc.c | 2 ++
 1 file changed, 2 insertions(+)

index 37c7a57afee5c..0b9b23eb7c2c3 100644
@@ -157,6 +157,8 @@ static int amd_pmc_setup_smu_logging(struct amd_pmc_dev *dev)
 			return -ENOMEM;
 	}
 
+	memset_io(dev->smu_virt_addr, 0, sizeof(struct smu_metrics));
+
 	/* Start the logging */
 	amd_pmc_send_cmd(dev, 0, NULL, SMU_MSG_LOG_RESET, false);
 	amd_pmc_send_cmd(dev, 0, NULL, SMU_MSG_LOG_START, false);

2.43.0

Thank you for your contribution, it has been applied to my local review-ilpo-fixes branch. Note it will show up in the public platform-drivers-x86/review-ilpo-fixes branch only once I've pushed my local branch there, which might take a while.

The list of commits applied:
[1/1] platform/x86/amd: pmc: Clear metrics table at start of cycle

      commit: 4dbd11796f3a8eb95647507befc41995458a4023

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i.