platform/x86: amd-pmc: Validate entry into the deepest state on resume

Currently the only way to discover if a system went into the deepest sleep
state is to read from sysfs after you finished suspend.

To better illustrate to users that problems have occurred, check as part
of resume and display a warning.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20220310150920.560583-1-mario.limonciello@amd.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Author: superm1

drivers/platform/x86/amd-pmc.c

@@ -322,18 +322,38 @@ static int amd_pmc_idlemask_read(struct amd_pmc_dev *pdev, struct device *dev,
 	return 0;
 }
 
+static int get_metrics_table(struct amd_pmc_dev *pdev, struct smu_metrics *table)
+{
+	if (pdev->cpu_id == AMD_CPU_ID_PCO)
+		return -ENODEV;
+	memcpy_fromio(table, pdev->smu_virt_addr, sizeof(struct smu_metrics));
+	return 0;
+}
+
+static void amd_pmc_validate_deepest(struct amd_pmc_dev *pdev)
+{
+	struct smu_metrics table;
+
+	if (get_metrics_table(pdev, &table))
+		return;
+
+	if (!table.s0i3_last_entry_status)
+		dev_warn(pdev->dev, "Last suspend didn't reach deepest state\n");
+	else
+		dev_dbg(pdev->dev, "Last suspend in deepest state for %lluus\n",
+			 table.timein_s0i3_lastcapture);
+}
+
 #ifdef CONFIG_DEBUG_FS
 static int smu_fw_info_show(struct seq_file *s, void *unused)
 {
 	struct amd_pmc_dev *dev = s->private;
 	struct smu_metrics table;
 	int idx;
 
-	if (dev->cpu_id == AMD_CPU_ID_PCO)
+	if (get_metrics_table(dev, &table))
 		return -EINVAL;
 
-	memcpy_fromio(&table, dev->smu_virt_addr, sizeof(struct smu_metrics));
-
 	seq_puts(s, "\n=== SMU Statistics ===\n");
 	seq_printf(s, "Table Version: %d\n", table.table_version);
 	seq_printf(s, "Hint Count: %d\n", table.hint_count);
@@ -689,6 +709,9 @@ static int __maybe_unused amd_pmc_resume(struct device *dev)
 		cpu_latency_qos_update_request(&pdev->amd_pmc_pm_qos_req,
 						PM_QOS_DEFAULT_VALUE);
 
+	/* Notify on failed entry */
+	amd_pmc_validate_deepest(pdev);
+
 	return rc;
 }