Re: [PATCH v6 0/2] remoteproc: xlnx: remote crash recovery

[Mathieu Poirier <mathieu.poirier@linaro.org>]

On Mon, Jun 29, 2026 at 05:48:04PM -0700, Tanmay Shah wrote:
> Remote processor can crash or hang during normal execution. Linux
> remoteproc framework supports different mechanisms to recover the
> remote processor and re-establish the RPMsg communication in such case.
> 
> Crash reporting on AMD-Xilinx platform:
> 
> 1) Using debugfs node
> 
> User can report the crash to the core framework via debugfs node using
> following command:
> 
> echo 1 > /sys/kernel/debug/remoteproc/remoteproc0/crash
> 
> 2) Remoteproc notify to the host about crash state and crash reason
> via the resource table
> 
> This is a platform specific method where the remote firmware contains
> vendor specific resource to update the crash state and the crash
> reason. Then the remote notifies the crash to the host via mailbox
> notification. The host then will check this resource on every mbox
> notification and reports the crash to the core framework if needed.
> 
> Crash recovery mechanism on AMD-Xilnx platform:
> 
> There are two mechanisms available to recover the remote processor from
> the crash. 1) boot recovery, 2) attach on recovery
> 
> Remoteproc core framework will choose proper mechanism based on the
> rproc features set by the platform driver.
> 
> 1) Boot recovery
> 
> This is the default mechanism to recover the remote processor.
> In this method core framework will first stop the remote processor,
> load the firmware again and then starts the remote processor. On
> AMD-Xilinx platforms this method is supported. The default coredump
> method is supported.
> 
> 2) Attach on recovery
> 
> If RPROC_ATTACH_ON_RECOVERY feature is enabled by the platform driver,
> then the core framework will choose this method for recovery.
> 
> On versal and later platforms following is the sequence of events expected
> during remoteproc crash and attach on recovery:
> 
> a) Remoteproc attach/detach flow is working, and RPMsg comm is established
> b) Remote processor (RPU) crashed (crash not reported yet)
> c) Platform management controller is instructed to stop and reload elf
>    on inactive remote processor before reboot (platform specific method)
> d) Platform management controller reboots the remote processor
> e) Remote processor boots again, and detects previous crash (platform
>    specific mechanism to detect the crash)
> f) Remote processor Reports crash to the Linux (Host) and wait for
>    the recovery.
> g) Linux performs full detach and reattach to remote processor.
> h) Normal RPMsg communication is established.
> 
> It is required to destroy all RPMsg related resources and recreate them
> during recovery to establish successful RPMsg communication. To achieve
> this complete rproc_detach followed by rproc_boot calls are needed. That
> is what this patch-series is fixing along with adding rproc recovery
> methods for AMD-Xilinx platforms.
> 
> Change log:
> 
> Changes in v6:
>   - %s/XLNX_RPROC_FW_CRASH_REASON/XLNX_RPROC_FW_CRASH_REPORT/
>   - fix if else condition to reduce indent level
>   - %s/crash_state/crashed
>   - move setting rproc feature during probe
>   - remove redundant clearing of the features during detach() op
>

Applied.

Thanks,
Mathieu
 
> Changes in v5:
>   - cache crash report to a local variable then act on it.
>   - End crash report string with '\0' without relying on fw
> 
> Changes in v4:
>   - Optimize crash resource memory by changing type to u32 to u8
>   - Introduce version field in the crash resource
>   - Check crash related condition before rproc state related condition
>   - Move crash reporting to the bottom half of the isr instead of
>     actual irq handler
>   - Introduce 16 bytes array in the crash report to store crash reason
>     in the string format
>   - Remove redundant type cast
> 
> Changes in v3:
>   - %s/kick/mailbox notification/
>   - %s/core framework/rproc core framework/
>   - fold simple function within zynqmp_r5_handle_rsc().
>   - remove spurious change
>   - reset crash state after reporting the crash
>   - document set and reset of ATTACH_ON_RECOVERY flag
>   - set recovery_disabled flag to false
>   - check condition rproc->crash_reason != NULL
> 
> 
> Changes in v5:
>   - use local variable to access crash report pointer
>   - End crash report string with '\0' without relying on fw
> 
> Changes in v4:
>   - move pieces needed from rproc_detach() to rproc_attach_recovery() to
>     cleanup the resources
>   - use rproc_attach() over __rproc_attach() to create resources again
>   - keep rproc_trigger_recovery() unmodified
>   - Optimize crash resource memory by changing type to u32 to u8
>   - Introduce version field in the crash resource
>   - Check crash related condition before rproc state related condition
>   - Move crash reporting to the bottom half of the isr instead of
>     actual irq handler
>   - Introduce 16 bytes array in the crash report to store crash reason
>     in the string format
>   - Remove redundant type cast
> 
> Changes in 3: 
>   - both rproc_attach_recovery() and
>     rproc_boot_recovery() are called the same way.
>   - remove unrelated changes
>   - %s/kick/mailbox notification/
>   - %s/core framework/rproc core framework/
>   - fold simple function within zynqmp_r5_handle_rsc().
>   - remove spurious change
>   - reset crash state after reporting the crash
>   - document set and reset of ATTACH_ON_RECOVERY flag
>   - set recovery_disabled flag to false
>   - check condition rproc->crash_reason != NULL
> 
> Changes in v2:
>   - use rproc_boot instead of rproc_attach
>   - move debug message early in the function
>   - clear attach recovery boot flag during detach and stop ops
> 
> Tanmay Shah (2):
>   remoteproc: core: full attach detach during recovery
>   remoteproc: xlnx: add crash detection mechanism
> 
>  drivers/remoteproc/remoteproc_core.c    | 15 +++++-
>  drivers/remoteproc/xlnx_r5_remoteproc.c | 70 ++++++++++++++++++++++++-
>  2 files changed, 83 insertions(+), 2 deletions(-)
> 
> 
> base-commit: 78fb7968943f5064766af7f33d82e6bfe90e0db0
> -- 
> 2.34.1
>