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firmware: xilinx: Clear firmware notifiers across kexec transitions

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During a kexec restart, only the kernel is reloaded but notifier callbacks
in firmware persist, causing state mismatches between kernel and firmware.

To address this, introduce PM_ALL_NOTIFIERS node ID to unregister all
notifier callbacks during kexec. On a graceful kexec restart, this occurs
in zynqmp_firmware_shutdown(). On a crash kernel restart, it happens in
zynqmp_firmware_probe() in the reloaded kernel.

Unregistering all notifiers depends on firmware support for the
PM_ALL_NOTIFIERS node ID. On firmware that does not implement it (the
feature check reports a version below PM_API_VERSION_3) the step is
skipped and a warning such as "Firmware doesn't support unregister all
notifiers at once" is logged, e.g. on Versal NET firmware that predates
this API.

Signed-off-by: Jay Buddhabhatti <jay.buddhabhatti@amd.com>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Reviewed-by: Prasanna Kumar T S M <ptsm@linux.microsoft.com>
Link: https://patch.msgid.link/20260729122522.3732875-4-jay.buddhabhatti@amd.com
Signed-off-by: Michal Simek <michal.simek@amd.com>
This commit is contained in:
Jay Buddhabhatti 2026-07-29 05:25:22 -07:00 committed by Michal Simek
parent 84dbfa5519
commit 0e8860367d
2 changed files with 17 additions and 0 deletions
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14
drivers/firmware/xilinx/zynqmp.c
View File

@ -2115,6 +2115,20 @@ static int zynqmp_clear_pm_state(struct device *dev)
"Bulk device release is not supported by firmware: %d\n", ret);
ret = 0;
}
/* Check if the firmware supports the PM_ALL_NOTIFIERS node ID */
ret = do_feature_check_call(PM_REGISTER_NOTIFIER);
if (ret >= 0 && ((ret & FIRMWARE_VERSION_MASK) >= PM_API_VERSION_3)) {
/* Attempt to unregister all notifier callbacks via firmware */
ret = zynqmp_pm_register_notifier(PM_ALL_NOTIFIERS, 0, 0, 0);
if (ret)
dev_err(dev, "Failed to unregister all notifiers: %d\n", ret);
} else {
dev_warn(dev,
"Firmware doesn't support unregister all notifiers at once: %d\n",
ret);
ret = 0;
}
}
return ret;

3
include/linux/firmware/xlnx-zynqmp.h
View File

@ -149,6 +149,9 @@
/* Node ID for all peripheral devices */
#define PM_DEV_ALL_PERIPH 0x18224FFFU
/* Node ID for all notifier callbacks */
#define PM_ALL_NOTIFIERS 0xFFFFFFFFU
enum pm_module_id {
PM_MODULE_ID = 0x0,
XPM_MODULE_ID = 0x2,