i3c: mipi-i3c-hci: Preserve RUN bit when aborting DMA ring

The MIPI I3C HCI specification does not require the DMA ring RUN bit
(RUN_STOP) to be cleared when issuing an ABORT.  That allows the DMA ring
to continue to receive IBIs, although an IBI is anyway not lost because it
can be received once the ring restarts if the I3C device has not given up.
Note, currently ABORT is only used on a timeout error path so the change
has very little effect in practice.  In the more common case of a transfer
error, the ring (bundle) operation is halted by the controller anyway.

Adjust the RING_CONTROL handling to set ABORT without clearing RUN_STOP,
bringing the driver into alignment with the specification.

Fixes: b795e68bf3073 ("i3c: mipi-i3c-hci: Correct RING_CTRL_ABORT handling in DMA dequeue")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260603090754.16252-3-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

diff --git a/drivers/i3c/master/mipi-i3c-hci/dma.c b/drivers/i3c/master/mipi-i3c-hci/dma.c
index e4daaa6120550d7b0985a6f9bc5d89be2dc3cc0e..bdffdd8b892368c07ba22a0060b1e872c1806491 100644 (file)
--- a/drivers/i3c/master/mipi-i3c-hci/dma.c
+++ b/drivers/i3c/master/mipi-i3c-hci/dma.c
@@ -554,7 +554,7 @@ static bool hci_dma_dequeue_xfer(struct i3c_hci *hci,
        if (ring_status & RING_STATUS_RUNNING) {
                /* stop the ring */
                reinit_completion(&rh->op_done);
-               rh_reg_write(RING_CONTROL, RING_CTRL_ENABLE | RING_CTRL_ABORT);
+               rh_reg_write(RING_CONTROL, rh_reg_read(RING_CONTROL) | RING_CTRL_ABORT);
                wait_for_completion_timeout(&rh->op_done, HZ);
                ring_status = rh_reg_read(RING_STATUS);
                if (ring_status & RING_STATUS_RUNNING) {