platform/x86/amd: pmc: Get STB DRAM size from PMFW

Recent PMFW's have support for querying the STB DRAM size. Add this
support to the driver.
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Co-developed-by: Sanket Goswami <Sanket.Goswami@amd.com>
Signed-off-by: Sanket Goswami <Sanket.Goswami@amd.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Link: https://lore.kernel.org/r/20230525141929.866385-3-Shyam-sundar.S-k@amd.comSigned-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/x86/amd/pmc.c

@@ -115,6 +115,7 @@ enum s2d_arg {
 	S2D_PHYS_ADDR_LOW,
 	S2D_PHYS_ADDR_HIGH,
 	S2D_NUM_SAMPLES,
+	S2D_DRAM_SIZE,
 };
 
 struct amd_pmc_bit_map {
@@ -147,6 +148,7 @@ struct amd_pmc_dev {
 	u32 base_addr;
 	u32 cpu_id;
 	u32 active_ips;
+	u32 dram_size;
 /* SMU version information */
 	u8 smu_program;
 	u8 major;
@@ -890,11 +892,39 @@ static const struct pci_device_id pmc_pci_ids[] = {
 	{ }
 };
 
+static int amd_pmc_get_dram_size(struct amd_pmc_dev *dev)
+{
+	int ret;
+
+	switch (dev->cpu_id) {
+	case AMD_CPU_ID_YC:
+		if (!(dev->major > 90 || (dev->major == 90 && dev->minor > 39))) {
+			ret = -EINVAL;
+			goto err_dram_size;
+		}
+		break;
+	default:
+		ret = -EINVAL;
+		goto err_dram_size;
+	}
+
+	ret = amd_pmc_send_cmd(dev, S2D_DRAM_SIZE, &dev->dram_size, STB_SPILL_TO_DRAM, true);
+	if (ret || !dev->dram_size)
+		goto err_dram_size;
+
+	return 0;
+
+err_dram_size:
+	dev_err(dev->dev, "DRAM size command not supported for this platform\n");
+	return ret;
+}
+
 static int amd_pmc_s2d_init(struct amd_pmc_dev *dev)
 {
 	u32 phys_addr_low, phys_addr_hi;
 	u64 stb_phys_addr;
 	u32 size = 0;
+	int ret;
 
 	/* Spill to DRAM feature uses separate SMU message port */
 	dev->msg_port = 1;
@@ -903,6 +933,11 @@ static int amd_pmc_s2d_init(struct amd_pmc_dev *dev)
 	if (size != S2D_TELEMETRY_BYTES_MAX)
 		return -EIO;
 
+	/* Get DRAM size */
+	ret = amd_pmc_get_dram_size(dev);
+	if (ret)
+		dev->dram_size = S2D_TELEMETRY_DRAMBYTES_MAX;
+
 	/* Get STB DRAM address */
 	amd_pmc_send_cmd(dev, S2D_PHYS_ADDR_LOW, &phys_addr_low, STB_SPILL_TO_DRAM, true);
 	amd_pmc_send_cmd(dev, S2D_PHYS_ADDR_HIGH, &phys_addr_hi, STB_SPILL_TO_DRAM, true);
@@ -912,7 +947,7 @@ static int amd_pmc_s2d_init(struct amd_pmc_dev *dev)
 	/* Clear msg_port for other SMU operation */
 	dev->msg_port = 0;
 
-	dev->stb_virt_addr = devm_ioremap(dev->dev, stb_phys_addr, S2D_TELEMETRY_DRAMBYTES_MAX);
+	dev->stb_virt_addr = devm_ioremap(dev->dev, stb_phys_addr, dev->dram_size);
 	if (!dev->stb_virt_addr)
 		return -ENOMEM;