Re: [PATCH V3 00/16] i3c: mipi-i3c-hci: DMA abort, recovery and related improvements

[Adrian Hunter]

On 04/05/2026 14:33, Adrian Hunter wrote:
> Hi
> 
> This series improves the robustness of the MIPI I3C HCI DMA mode driver,
> addressing issues observed during error handling and recovery.

Any comments on this?

> 
> Patch 1 ensures suspend always invokes io->suspend.
> 
> Patches 2-4 fix issues in the existing DMA abort path: preserving the RUN
> bit during abort per the MIPI specification, blocking enqueue during
> abort/error, and waiting for ring restart completion.
> 
> Patches 5-8 improve how partially completed transfer lists are handled
> during dequeue: moving hci_dma_xfer_done() earlier so completed
> responses are processed before NoOp replacement, completing transfer
> lists immediately on error rather than deferring, and detecting when an
> abort races with transfer completion to avoid restarting the wrong
> transfer list.
> 
> Patches 9-10 add Intel-specific quirks for DMA ring abort: a PIO queue
> reset after abort, and an HC_CONTROL ABORT before the ring-level abort.
> 
> Patch 11 factors out a reset-and-restore helper from the suspend path
> for reuse.
> 
> Patch 12 adds a full DMA recovery path for internal controller errors.
> When the hardware reports a TID mismatch or the ring becomes stuck, the
> driver now resets and restores the controller, terminating all in-flight
> transfers with an error status.
> 
> Patch 13 makes NoOp command handling observable: instead of discarding
> NoOp responses, the driver now waits for them to complete and triggers
> recovery if they fail.
> 
> Patch 14 adjusts transfer timeout accounting to start from when a
> transfer actually begins execution rather than when it was queued,
> preventing premature timeouts behind slow predecessors.
> 
> Patches 15-16 are minor optimizations: consolidating the DMA command and
> response ring into a single coherent allocation, and increasing the ring
> size to the maximum 255 entries to avoid ring-space exhaustion.
> 
> 
> Changes in V3:
> 
>   i3c: mipi-i3c-hci: Fix suspend behavior when bus disable falls back to software reset
>   i3c: mipi-i3c-hci: Preserve RUN bit when aborting DMA ring
> 	Add Frank's rev'd-by
> 
>   i3c: mipi-i3c-hci: Add DMA-mode recovery for internal controller errors
> 	When erroring out transfers, ensure the final transfer of a
> 	transfer list is processed last
> 
> 
> Changes in V2:
> 
>   i3c: mipi-i3c-hci: Fix suspend behavior when bus disable falls back to software reset
> 	Always return 0 from suspend callback
> 	Amend commit message
> 
>   i3c: mipi-i3c-hci: Preserve RUN bit when aborting DMA ring
> 	Improve commit message
> 
>   i3c: mipi-i3c-hci: Prevent DMA enqueue while ring is aborting or in error
> 	Improve commit message
> 
>   i3c: mipi-i3c-hci: Wait for DMA ring restart to complete
> 	None
> 
>   i3c: mipi-i3c-hci: Move hci_dma_xfer_done() definition
> 	Add Frank's Rev'd-by
> 
>   i3c: mipi-i3c-hci: Call hci_dma_xfer_done() from dequeue path
> 	Add Frank's Rev'd-by
> 
>   i3c: mipi-i3c-hci: Complete transfer lists immediately on error
> 	Rename completing_xfer to final_xfer
> 
>   i3c: mipi-i3c-hci: Avoid restarting DMA ring after aborting wrong transfer
> 	Rename completing_xfer to final_xfer
> 
>   i3c: mipi-i3c-hci: Add DMA ring abort/reset quirk for Intel controllers
> 	None
> 
>   i3c: mipi-i3c-hci: Add DMA ring abort quirk for Intel controllers
> 	None
> 
>   i3c: mipi-i3c-hci: Factor out reset-and-restore helper
> 	Drop redundant i3c_hci_sync_irq_inactive(hci)
> 	from i3c_hci_reset_and_restore() because it is called by
> 	hci->io->suspend() anyway
> 
>   i3c: mipi-i3c-hci: Add DMA-mode recovery for internal controller errors
> 	Rename completing_xfer to final_xfer
> 	Add hci_dma_xfer_done() before checking for an already complete
> 	transfer
> 	Improve commit message
> 
>   i3c: mipi-i3c-hci: Wait for NoOp commands to complete
> 	Rename completing_xfer to final_xfer
> 	Add missing reinit_completion()
> 
>   i3c: mipi-i3c-hci: Base timeouts on actual transfer start time
> 	Do not flag the next transfer as started when there is an error
> 	which halts the controller
> 	Instead flag it started at the end of hci_dma_dequeue_xfer()
> 	Use hci_start_xfer() in pio.c
> 
>   i3c: mipi-i3c-hci: Consolidate DMA ring allocation
> 	Check for failed allocation before assignments to avoid doing
> 	arithmetic with NULL pointers
> 
>   i3c: mipi-i3c-hci: Increase DMA transfer ring size to maximum
> 	None
> 
> 
> Adrian Hunter (16):
>   i3c: mipi-i3c-hci: Fix suspend behavior when bus disable falls back to software reset
>   i3c: mipi-i3c-hci: Preserve RUN bit when aborting DMA ring
>   i3c: mipi-i3c-hci: Prevent DMA enqueue while ring is aborting or in error
>   i3c: mipi-i3c-hci: Wait for DMA ring restart to complete
>   i3c: mipi-i3c-hci: Move hci_dma_xfer_done() definition
>   i3c: mipi-i3c-hci: Call hci_dma_xfer_done() from dequeue path
>   i3c: mipi-i3c-hci: Complete transfer lists immediately on error
>   i3c: mipi-i3c-hci: Avoid restarting DMA ring after aborting wrong transfer
>   i3c: mipi-i3c-hci: Add DMA ring abort/reset quirk for Intel controllers
>   i3c: mipi-i3c-hci: Add DMA ring abort quirk for Intel controllers
>   i3c: mipi-i3c-hci: Factor out reset-and-restore helper
>   i3c: mipi-i3c-hci: Add DMA-mode recovery for internal controller errors
>   i3c: mipi-i3c-hci: Wait for NoOp commands to complete
>   i3c: mipi-i3c-hci: Base timeouts on actual transfer start time
>   i3c: mipi-i3c-hci: Consolidate DMA ring allocation
>   i3c: mipi-i3c-hci: Increase DMA transfer ring size to maximum
> 
>  drivers/i3c/master/mipi-i3c-hci/cmd.h  |   6 +
>  drivers/i3c/master/mipi-i3c-hci/core.c |  82 ++++++--
>  drivers/i3c/master/mipi-i3c-hci/dma.c  | 344 +++++++++++++++++++++++++--------
>  drivers/i3c/master/mipi-i3c-hci/hci.h  |  22 +++
>  drivers/i3c/master/mipi-i3c-hci/pio.c  |   1 +
>  5 files changed, 365 insertions(+), 90 deletions(-)
> 
> 
> Regards
> Adrian