firmware: ti_sci: Set IO Isolation only if the firmware is capable

Prevent calling ti_sci_cmd_set_io_isolation() on firmware
that does not support the IO_ISOLATION capability. Add the
MSG_FLAG_CAPS_IO_ISOLATION capability flag and check it before
attempting to set IO isolation during suspend/resume operations.

Without this check, systems with older firmware may experience
undefined behavior or errors when entering/exiting suspend states.

Fixes: ec24643bdd62 ("firmware: ti_sci: Add system suspend and resume call")
Signed-off-by: Thomas Richard (TI.com) <thomas.richard@bootlin.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Link: https://patch.msgid.link/20251031-ti-sci-io-isolation-v2-1-60d826b65949@bootlin.com
Signed-off-by: Nishanth Menon <nm@ti.com>

2 files changed, 15 insertions, 8 deletions

diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
index 99a2e0e2960f..34df75cf42fd 100644
--- a/drivers/firmware/ti_sci.c
+++ b/drivers/firmware/ti_sci.c
@@ -3751,9 +3751,11 @@ static int ti_sci_suspend_noirq(struct device *dev)
 	struct ti_sci_info *info = dev_get_drvdata(dev);
 	int ret = 0;
 
-	ret = ti_sci_cmd_set_io_isolation(&info->handle, TISCI_MSG_VALUE_IO_ENABLE);
-	if (ret)
-		return ret;
+	if (info->fw_caps & MSG_FLAG_CAPS_IO_ISOLATION) {
+		ret = ti_sci_cmd_set_io_isolation(&info->handle, TISCI_MSG_VALUE_IO_ENABLE);
+		if (ret)
+			return ret;
+	}
 
 	return 0;
 }
@@ -3767,9 +3769,11 @@ static int ti_sci_resume_noirq(struct device *dev)
 	u8 pin;
 	u8 mode;
 
-	ret = ti_sci_cmd_set_io_isolation(&info->handle, TISCI_MSG_VALUE_IO_DISABLE);
-	if (ret)
-		return ret;
+	if (info->fw_caps & MSG_FLAG_CAPS_IO_ISOLATION) {
+		ret = ti_sci_cmd_set_io_isolation(&info->handle, TISCI_MSG_VALUE_IO_DISABLE);
+		if (ret)
+			return ret;
+	}
 
 	ret = ti_sci_msg_cmd_lpm_wake_reason(&info->handle, &source, &time, &pin, &mode);
 	/* Do not fail to resume on error as the wake reason is not critical */
@@ -3926,11 +3930,12 @@ static int ti_sci_probe(struct platform_device *pdev)
 	}
 
 	ti_sci_msg_cmd_query_fw_caps(&info->handle, &info->fw_caps);
-	dev_dbg(dev, "Detected firmware capabilities: %s%s%s%s\n",
+	dev_dbg(dev, "Detected firmware capabilities: %s%s%s%s%s\n",
 		info->fw_caps & MSG_FLAG_CAPS_GENERIC ? "Generic" : "",
 		info->fw_caps & MSG_FLAG_CAPS_LPM_PARTIAL_IO ? " Partial-IO" : "",
 		info->fw_caps & MSG_FLAG_CAPS_LPM_DM_MANAGED ? " DM-Managed" : "",
-		info->fw_caps & MSG_FLAG_CAPS_LPM_ABORT ? " LPM-Abort" : ""
+		info->fw_caps & MSG_FLAG_CAPS_LPM_ABORT ? " LPM-Abort" : "",
+		info->fw_caps & MSG_FLAG_CAPS_IO_ISOLATION ? " IO-Isolation" : ""
 	);
 
 	ti_sci_setup_ops(info);
diff --git a/drivers/firmware/ti_sci.h b/drivers/firmware/ti_sci.h
index 701c416b2e78..7559cde17b6c 100644
--- a/drivers/firmware/ti_sci.h
+++ b/drivers/firmware/ti_sci.h
@@ -149,6 +149,7 @@ struct ti_sci_msg_req_reboot {
  *		MSG_FLAG_CAPS_LPM_PARTIAL_IO: Partial IO in LPM
  *		MSG_FLAG_CAPS_LPM_DM_MANAGED: LPM can be managed by DM
  *		MSG_FLAG_CAPS_LPM_ABORT: Abort entry to LPM
+ *		MSG_FLAG_CAPS_IO_ISOLATION: IO Isolation support
  *
  * Response to a generic message with message type TI_SCI_MSG_QUERY_FW_CAPS
  * providing currently available SOC/firmware capabilities. SoC that don't
@@ -160,6 +161,7 @@ struct ti_sci_msg_resp_query_fw_caps {
 #define MSG_FLAG_CAPS_LPM_PARTIAL_IO	TI_SCI_MSG_FLAG(4)
 #define MSG_FLAG_CAPS_LPM_DM_MANAGED	TI_SCI_MSG_FLAG(5)
 #define MSG_FLAG_CAPS_LPM_ABORT		TI_SCI_MSG_FLAG(9)
+#define MSG_FLAG_CAPS_IO_ISOLATION	TI_SCI_MSG_FLAG(7)
 #define MSG_MASK_CAPS_LPM		GENMASK_ULL(4, 1)
 	u64 fw_caps;
 } __packed;