[PATCH 5.15 191/570] i3c: mipi-i3c-hci: Restart DMA ring correctly after dequeue abort

Greg Kroah-Hartman
2026-04-13T16:28:07Z

From: Adrian Hunter <adrian.hunter@intel.com>

commit b6d586431ae20d5157ee468d0ef62ad26798ef13 upstream.

The DMA dequeue path attempts to restart the ring after aborting an
in-flight transfer, but the current sequence is incomplete. The controller
must be brought out of the aborted state and the ring control registers
must be programmed in the correct order: first clearing ABORT, then
re-enabling the ring and asserting RUN_STOP to resume operation.

Add the missing controller resume step and update the ring control writes
so that the ring is restarted using the proper sequence.

Fixes: 9ad9a52cce282 ("i3c/master: introduce the mipi-i3c-hci driver")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260306072451.11131-11-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/i3c/master/mipi-i3c-hci/dma.c | 2 ++
1 file changed, 2 insertions(+)

--- a/drivers/i3c/master/mipi-i3c-hci/dma.c
+++ b/drivers/i3c/master/mipi-i3c-hci/dma.c
@@ -491,7 +491,9 @@ static bool hci_dma_dequeue_xfer(struct
}

/* restart the ring */
+ mipi_i3c_hci_resume(hci);
rh_reg_write(RING_CONTROL, RING_CTRL_ENABLE);
+ rh_reg_write(RING_CONTROL, RING_CTRL_ENABLE | RING_CTRL_RUN_STOP);

return did_unqueue;
}