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

["Pandey, Radhey Shyam" <radheys@amd.com>]

On 9/23/2026 3:33 PM, Jay Buddhabhatti wrote:
> 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@amd.com>

Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Thanks!

> ---
>   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 */