platform/x86: amd-pmc: Move SMU logging setup out of init

SMU logging is setup when the device is probed currently.

In analyzing boot performance it was observed that amd_pmc_probe is
taking ~116800us on startup on an OEM platform.  This is longer than
expected, and is caused by enabling SMU logging at startup.

As the SMU logging is only needed for debugging, initialize it only upon
use.  This decreases the time for amd_pmc_probe to ~28800us.
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20220411143820.13971-1-mario.limonciello@amd.comSigned-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/x86/amd-pmc.c

@@ -164,6 +164,7 @@ static int amd_pmc_read_stb(struct amd_pmc_dev *dev, u32 *buf);
 #ifdef CONFIG_SUSPEND
 static int amd_pmc_write_stb(struct amd_pmc_dev *dev, u32 data);
 #endif
+static int amd_pmc_setup_smu_logging(struct amd_pmc_dev *dev);
 
 static inline u32 amd_pmc_reg_read(struct amd_pmc_dev *dev, int reg_offset)
 {
@@ -321,6 +322,13 @@ static int amd_pmc_idlemask_read(struct amd_pmc_dev *pdev, struct device *dev,
 
 static int get_metrics_table(struct amd_pmc_dev *pdev, struct smu_metrics *table)
 {
+	if (!pdev->smu_virt_addr) {
+		int ret = amd_pmc_setup_smu_logging(pdev);
+
+		if (ret)
+			return ret;
+	}
+
 	if (pdev->cpu_id == AMD_CPU_ID_PCO)
 		return -ENODEV;
 	memcpy_fromio(table, pdev->smu_virt_addr, sizeof(struct smu_metrics));
@@ -451,25 +459,32 @@ static inline void amd_pmc_dbgfs_unregister(struct amd_pmc_dev *dev)
 
 static int amd_pmc_setup_smu_logging(struct amd_pmc_dev *dev)
 {
-	u32 phys_addr_low, phys_addr_hi;
-	u64 smu_phys_addr;
-
-	if (dev->cpu_id == AMD_CPU_ID_PCO)
+	if (dev->cpu_id == AMD_CPU_ID_PCO) {
+		dev_warn_once(dev->dev, "SMU debugging info not supported on this platform\n");
 		return -EINVAL;
+	}
 
 	/* Get Active devices list from SMU */
-	amd_pmc_send_cmd(dev, 0, &dev->active_ips, SMU_MSG_GET_SUP_CONSTRAINTS, 1);
+	if (!dev->active_ips)
+		amd_pmc_send_cmd(dev, 0, &dev->active_ips, SMU_MSG_GET_SUP_CONSTRAINTS, 1);
 
 	/* Get dram address */
-	amd_pmc_send_cmd(dev, 0, &phys_addr_low, SMU_MSG_LOG_GETDRAM_ADDR_LO, 1);
-	amd_pmc_send_cmd(dev, 0, &phys_addr_hi, SMU_MSG_LOG_GETDRAM_ADDR_HI, 1);
-	smu_phys_addr = ((u64)phys_addr_hi << 32 | phys_addr_low);
-
-	dev->smu_virt_addr = devm_ioremap(dev->dev, smu_phys_addr, sizeof(struct smu_metrics));
-	if (!dev->smu_virt_addr)
-		return -ENOMEM;
+	if (!dev->smu_virt_addr) {
+		u32 phys_addr_low, phys_addr_hi;
+		u64 smu_phys_addr;
+
+		amd_pmc_send_cmd(dev, 0, &phys_addr_low, SMU_MSG_LOG_GETDRAM_ADDR_LO, 1);
+		amd_pmc_send_cmd(dev, 0, &phys_addr_hi, SMU_MSG_LOG_GETDRAM_ADDR_HI, 1);
+		smu_phys_addr = ((u64)phys_addr_hi << 32 | phys_addr_low);
+
+		dev->smu_virt_addr = devm_ioremap(dev->dev, smu_phys_addr,
+						  sizeof(struct smu_metrics));
+		if (!dev->smu_virt_addr)
+			return -ENOMEM;
+	}
 
 	/* Start the logging */
+	amd_pmc_send_cmd(dev, 0, NULL, SMU_MSG_LOG_RESET, 0);
 	amd_pmc_send_cmd(dev, 0, NULL, SMU_MSG_LOG_START, 0);
 
 	return 0;
@@ -639,8 +654,7 @@ static void amd_pmc_s2idle_prepare(void)
 	u32 arg = 1;
 
 	/* Reset and Start SMU logging - to monitor the s0i3 stats */
-	amd_pmc_send_cmd(pdev, 0, NULL, SMU_MSG_LOG_RESET, 0);
-	amd_pmc_send_cmd(pdev, 0, NULL, SMU_MSG_LOG_START, 0);
+	amd_pmc_setup_smu_logging(pdev);
 
 	/* Activate CZN specific RTC functionality */
 	if (pdev->cpu_id == AMD_CPU_ID_CZN) {
@@ -854,11 +868,6 @@ static int amd_pmc_probe(struct platform_device *pdev)
 		goto err_pci_dev_put;
 	}
 
-	/* Use SMU to get the s0i3 debug stats */
-	err = amd_pmc_setup_smu_logging(dev);
-	if (err)
-		dev_err(dev->dev, "SMU debugging info not supported on this platform\n");
-
 	if (enable_stb && dev->cpu_id == AMD_CPU_ID_YC) {
 		err = amd_pmc_s2d_init(dev);
 		if (err)