platform/x86/amd/pmc: Add PMFW command id to support S2D force flush

Recent PMFW have the capability that can force flush the FIFO
contents to DRAM on sending a command id via the mailbox. Add this support
to the driver.
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/20230910142034.2967110-1-Shyam-sundar.S-k@amd.com
[ij: Corrected whitespace in dev_dbg_once()]
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

drivers/platform/x86/amd/pmc/pmc.c

@@ -55,6 +55,9 @@
 #define S2D_TELEMETRY_BYTES_MAX		0x100000
 #define S2D_TELEMETRY_DRAMBYTES_MAX	0x1000000
 
+/* STB Spill to DRAM Message Definition */
+#define STB_FORCE_FLUSH_DATA		0xCF
+
 /* Base address of SMU for mapping physical address to virtual address */
 #define AMD_PMC_MAPPING_SIZE		0x01000
 #define AMD_PMC_BASE_ADDR_OFFSET	0x10000
@@ -236,7 +239,7 @@ static const struct file_operations amd_pmc_stb_debugfs_fops = {
 static int amd_pmc_stb_debugfs_open_v2(struct inode *inode, struct file *filp)
 {
 	struct amd_pmc_dev *dev = filp->f_inode->i_private;
-	u32 *buf, fsize, num_samples, stb_rdptr_offset = 0;
+	u32 *buf, fsize, num_samples, val, stb_rdptr_offset = 0;
 	int ret;
 
 	/* Write dummy postcode while reading the STB buffer */
@@ -251,6 +254,10 @@ static int amd_pmc_stb_debugfs_open_v2(struct inode *inode, struct file *filp)
 	/* Spill to DRAM num_samples uses separate SMU message port */
 	dev->msg_port = 1;
 
+	ret = amd_pmc_send_cmd(dev, 0, &val, STB_FORCE_FLUSH_DATA, 1);
+	if (ret)
+		dev_dbg_once(dev->dev, "S2D force flush not supported: %d\n", ret);
+
 	/* Get the num_samples to calculate the last push location */
 	ret = amd_pmc_send_cmd(dev, S2D_NUM_SAMPLES, &num_samples, dev->s2d_msg_id, true);
 	/* Clear msg_port for other SMU operation */