[PATCH 2/4] firmware: xilinx: Release all peripheral devices from firmware

[Jay Buddhabhatti <jay.buddhabhatti@amd.com>]

During a kexec restart, only the kernel is reloaded while devices
allocated in firmware persist, causing state mismatches between the
kernel and firmware.

Introduce PM_DEV_ALL_PERIPH node ID (0x18224FFFU) to release all
peripheral devices during kexec. On graceful restarts, this happens in
zynqmp_firmware_shutdown(). On crash kernel restarts, it happens in
zynqmp_firmware_probe() of the reloaded kernel.

Releasing all peripherals depends on firmware support for the
PM_DEV_ALL_PERIPH node ID. On firmware that does not implement it (the
feature check reports a version below PM_API_VERSION_3) the release is
skipped and a warning such as "Bulk device release is not supported by
firmware" is logged, e.g. on Versal NET firmware that predates this API.

Signed-off-by: Jay Buddhabhatti <jay.buddhabhatti@amd.com>
---
 drivers/firmware/xilinx/zynqmp.c     | 15 ++++++++++++++-
 include/linux/firmware/xlnx-zynqmp.h |  4 ++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
index 95ffd8f33ce9..64d2109eefd2 100644
--- a/drivers/firmware/xilinx/zynqmp.c
+++ b/drivers/firmware/xilinx/zynqmp.c
@@ -2070,7 +2070,7 @@ ATTRIBUTE_GROUPS(zynqmp_firmware);
  * zynqmp_clear_pm_state() - Clear subsystem state
  * @dev: Device pointer used for logging
  *
- * Clears PM specific data in TF-A.
+ * Clears PM specific data in TF-A and firmware.
  *
  * Return: Returns status, either success or error
  */
@@ -2097,6 +2097,19 @@ static int zynqmp_clear_pm_state(struct device *dev)
 			dev_warn(dev, "TF_A_CLEAR_PM_STATE is not supported in TF-A: %d\n", ret);
 			ret = 0;
 		}
+
+		/* Check if the firmware supports the PM_DEV_ALL_PERIPH node ID */
+		ret = do_feature_check_call(PM_RELEASE_NODE);
+		if (ret >= 0 && ((ret & FIRMWARE_VERSION_MASK) >= PM_API_VERSION_3)) {
+			/* Attempt to release all peripheral devices via firmware */
+			ret = zynqmp_pm_release_node(PM_DEV_ALL_PERIPH);
+			if (ret)
+				dev_err(dev, "Failed to release all peripheral devices: %d\n", ret);
+		} else {
+			dev_warn(dev,
+				 "Bulk device release is not supported by firmware: %d\n", ret);
+			ret = 0;
+		}
 	}
 
 	return ret;
diff --git a/include/linux/firmware/xlnx-zynqmp.h b/include/linux/firmware/xlnx-zynqmp.h
index baaa88b0b197..ac39e5492961 100644
--- a/include/linux/firmware/xlnx-zynqmp.h
+++ b/include/linux/firmware/xlnx-zynqmp.h
@@ -50,6 +50,7 @@
 /* PM API versions */
 #define PM_API_VERSION_1	1
 #define PM_API_VERSION_2	2
+#define PM_API_VERSION_3	3
 
 #define PM_PINCTRL_PARAM_SET_VERSION	2
 
@@ -145,6 +146,9 @@
 #define XPM_EVENT_ERROR_MASK_NOC_NCR		BIT(13)
 #define XPM_EVENT_ERROR_MASK_NOC_CR		BIT(12)
 
+/* Node ID for all peripheral devices */
+#define PM_DEV_ALL_PERIPH	0x18224FFFU
+
 enum pm_module_id {
 	PM_MODULE_ID = 0x0,
 	XPM_MODULE_ID = 0x2,
-- 
2.34.1