[PATCH] firmware: xilinx: Request pre-allocated peripheral nodes after bulk release

[Jay Buddhabhatti]

During a kexec restart, zynqmp_clear_pm_state() releases all peripheral
devices via PM_DEV_ALL_PERIPH. Pre-allocated nodes are then left released,
so Linux no longer owns them and later peripheral access can fail.

Immediately re-request those nodes with zynqmp_pm_request_node(
PM_DEV_ALL_PERIPH, ...) so Linux retains ownership. On a graceful kexec
this runs from zynqmp_firmware_shutdown(). On a crash kernel restart it
runs from zynqmp_firmware_probe() in the reloaded kernel.

The bulk request depends on firmware support for PM_DEV_ALL_PERIPH
(PM_REQUEST_NODE feature check version >= PM_API_VERSION_3). On firmware
that does not implement it, the request is skipped and a warning is
logged. Errors are already logged inside zynqmp_clear_pm_state() and
zynqmp_firmware_probe() does not abort if the request fails.

Also, drop the redundant ret = 0 assignments whose value is overwritten
by the next do_feature_check_call()

Signed-off-by: Jay Buddhabhatti <jay.buddhabhatti at amd.com>
---
 drivers/firmware/xilinx/zynqmp.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
index fe650747ac91..96dbb23eb673 100644
--- a/drivers/firmware/xilinx/zynqmp.c
+++ b/drivers/firmware/xilinx/zynqmp.c
@@ -2193,7 +2193,6 @@ static int zynqmp_clear_pm_state(struct device *dev)
 					"Failed to clear EL3 PM subsystem state: %d\n", ret);
 		} else {
 			dev_warn(dev, "TF_A_CLEAR_PM_STATE is not supported by EL3 firmware: %d\n", ret);
-			ret = 0;
 		}
 
 		/* Check if the firmware supports the PM_DEV_ALL_PERIPH node ID */
@@ -2206,7 +2205,19 @@ static int zynqmp_clear_pm_state(struct device *dev)
 		} else {
 			dev_warn(dev,
 				 "Bulk device release is not supported by firmware: %d\n", ret);
-			ret = 0;
+		}
+
+		/* Check if the firmware supports the PM_DEV_ALL_PERIPH node ID */
+		ret = do_feature_check_call(PM_REQUEST_NODE);
+		if (ret >= 0 && ((ret & FIRMWARE_VERSION_MASK) >= PM_API_VERSION_3)) {
+			/* Attempt to request all nodes via firmware */
+			ret = zynqmp_pm_request_node(PM_DEV_ALL_PERIPH, 0, 0, 0);
+			if (ret)
+				dev_err(dev, "Failed to request all peripheral devices: %d\n", ret);
+		} else {
+			dev_warn(dev,
+				 "Firmware doesn't support request all peripheral devices at once: %d\n",
+				 ret);
 		}
 
 		/* Check if the firmware supports the PM_ALL_NOTIFIERS node ID */
-- 
2.54.0