From 1ecfd30960d4377c2d85181608936dedd35bb171 Mon Sep 17 00:00:00 2001
From: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Date: Mon, 6 Feb 2023 20:38:52 +0530
Subject: [PATCH] platform/x86/amd: pmc: Add num_samples message id support to STB
Git-commit: 1ecfd30960d4377c2d85181608936dedd35bb171
Patch-mainline: v6.3-rc1
References: bsc#1210644

Recent PMFWs have the support for S2D_NUM_SAMPLES message ID that
can tell the current number of samples present within the STB DRAM.

num_samples returned would let the driver know the start of the read
from the last push location. This way, the driver would emit the
top most region of the STB DRAM.

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/20230206150855.1938810-2-Shyam-sundar.S-k@amd.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/platform/x86/amd/pmc.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/amd/pmc.c b/drivers/platform/x86/amd/pmc.c
index 3cbb01ec10e3..23440f70d3df 100644
--- a/drivers/platform/x86/amd/pmc.c
+++ b/drivers/platform/x86/amd/pmc.c
@@ -114,6 +114,7 @@ enum s2d_arg {
 	S2D_TELEMETRY_SIZE = 0x01,
 	S2D_PHYS_ADDR_LOW,
 	S2D_PHYS_ADDR_HIGH,
+	S2D_NUM_SAMPLES,
 };
 
 struct amd_pmc_bit_map {
@@ -246,13 +247,35 @@ 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;
+	u32 *buf, fsize, num_samples, stb_rdptr_offset = 0;
+	int ret;
 
 	buf = kzalloc(S2D_TELEMETRY_BYTES_MAX, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
 
-	memcpy_fromio(buf, dev->stb_virt_addr, S2D_TELEMETRY_BYTES_MAX);
+	/* Spill to DRAM num_samples uses separate SMU message port */
+	dev->msg_port = 1;
+
+	/* Get the num_samples to calculate the last push location */
+	ret = amd_pmc_send_cmd(dev, S2D_NUM_SAMPLES, &num_samples, STB_SPILL_TO_DRAM, 1);
+	/* Clear msg_port for other SMU operation */
+	dev->msg_port = 0;
+	if (ret) {
+		dev_err(dev->dev, "error: S2D_NUM_SAMPLES not supported : %d\n", ret);
+		return ret;
+	}
+
+	/* Start capturing data from the last push location */
+	if (num_samples > S2D_TELEMETRY_BYTES_MAX) {
+		fsize  = S2D_TELEMETRY_BYTES_MAX;
+		stb_rdptr_offset = num_samples - fsize;
+	} else {
+		fsize = num_samples;
+		stb_rdptr_offset = 0;
+	}
+
+	memcpy_fromio(buf, dev->stb_virt_addr + stb_rdptr_offset, fsize);
 	filp->private_data = buf;
 
 	return 0;
-- 
2.35.3