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>
---
Changes in v2:
- improve commit message
- Link to v1: https://lore.kernel.org/r/20251014-ti-sci-io-isolation-v1-1-67c7ce5d1b63@bootlin.com
---
 drivers/firmware/ti_sci.c | 21 +++++++++++++--------
 drivers/firmware/ti_sci.h |  2 ++
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
index 49fd2ae01055d0f425062147422471f0fd49e4bd..8d96a3c12b36a908097805b44dc3343172fbbfec 100644
--- a/drivers/firmware/ti_sci.c
+++ b/drivers/firmware/ti_sci.c
@@ -3751,9 +3751,11 @@ static int __maybe_unused 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 __maybe_unused 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 */
@@ -3928,11 +3932,12 @@ 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 701c416b2e78f8ef20ce6741a88ffa6fd4853b2d..7559cde17b6ccfeeb1bc357fce5c5767c3f75c54 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;

---
base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787
change-id: 20251013-ti-sci-io-isolation-63a8bcd9d4e9

Best regards,
-- 
Thomas Richard (TI.com) <thomas.richard@bootlin.com>

Hi Thomas Richard (TI.com),

On Fri, 31 Oct 2025 13:44:56 +0100, Thomas Richard (TI.com) wrote:
> 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.
> 
> [...]

I have applied the following to branch ti-drivers-soc-next on [1].
Thank you!

[1/1] firmware: ti_sci: set IO Isolation only if the firmware is capable
      commit: 999e9bc953e321651d69556fdd5dfd178f96f128

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent up the chain during
the next merge window (or sooner if it is a relevant bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/ti/linux.git
-- 
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D
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