[PATCH v2 1/6] platform/x86/amd/pmc: Restore msg_port on amd_stb_s2d_init() error paths

dev->msg_port is switched to MSG_PORT_S2D before issuing the S2D SMU
commands but is only restored to MSG_PORT_PMC on the success path.  The
early "return -EIO" and "return -ENOMEM" leave the port stuck on
MSG_PORT_S2D, so all subsequent SMU communication - including the s2idle
prepare/restore handlers - is directed at the wrong mailbox.

Consolidate the exit path through a single label so the message port is
always restored.

Reported-by: Ilpo Järvinen <[email protected]>
Closes: https://lore.kernel.org/platform-driver-x86/[email protected]/
Fixes: 3d7d407dfb05 ("platform/x86: amd-pmc: Add support for AMD Spill to DRAM STB feature")
Cc: [email protected]
Signed-off-by: Mario Limonciello <[email protected]>
---
 drivers/platform/x86/amd/pmc/mp1_stb.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/platform/x86/amd/pmc/mp1_stb.c b/drivers/platform/x86/amd/pmc/mp1_stb.c
index 753d630f3283d..83645c0a8d785 100644
--- a/drivers/platform/x86/amd/pmc/mp1_stb.c
+++ b/drivers/platform/x86/amd/pmc/mp1_stb.c
@@ -289,7 +289,7 @@ int amd_stb_s2d_init(struct amd_pmc_dev *dev)
 	u32 phys_addr_low, phys_addr_hi;
 	u64 stb_phys_addr;
 	u32 size = 0;
-	int ret;
+	int ret = 0;
 
 	if (!enable_stb)
 		return 0;
@@ -307,8 +307,10 @@ int amd_stb_s2d_init(struct amd_pmc_dev *dev)
 	dev->msg_port = MSG_PORT_S2D;
 
 	amd_pmc_send_cmd(dev, S2D_TELEMETRY_SIZE, &size, dev->stb_arg.s2d_msg_id, true);
-	if (size != S2D_TELEMETRY_BYTES_MAX)
-		return -EIO;
+	if (size != S2D_TELEMETRY_BYTES_MAX) {
+		ret = -EIO;
+		goto out;
+	}
 
 	/* Get DRAM size */
 	ret = amd_pmc_send_cmd(dev, S2D_DRAM_SIZE, &dev->dram_size, dev->stb_arg.s2d_msg_id, true);
@@ -321,12 +323,16 @@ int amd_stb_s2d_init(struct amd_pmc_dev *dev)
 
 	stb_phys_addr = ((u64)phys_addr_hi << 32 | phys_addr_low);
 
-	/* Clear msg_port for other SMU operation */
-	dev->msg_port = MSG_PORT_PMC;
-
 	dev->stb_virt_addr = devm_ioremap(dev->dev, stb_phys_addr, dev->dram_size);
-	if (!dev->stb_virt_addr)
-		return -ENOMEM;
+	if (!dev->stb_virt_addr) {
+		ret = -ENOMEM;
+		goto out;
+	}
 
-	return 0;
+	ret = 0;
+
+out:
+	/* Restore the default message port for subsequent SMU operations */
+	dev->msg_port = MSG_PORT_PMC;
+	return ret;
 }
-- 
2.43.0