[PATCH V5 02/17] i3c: mipi-i3c-hci: Preserve RUN bit when aborting DMA ring
Adrian Hunter <[email protected]>
| Newsgroups | org.infradead.lists.linux-i3c,org.kernel.vger.linux-kernel |
|---|---|
| Organization | Intel Finland Oy, Registered Address: c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo, Business Identity Code: 0357606 - 4, Domiciled in Helsinki |
| Message-ID | <[email protected]> |
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 <[email protected]>
Reviewed-by: Frank Li <[email protected]>
---
Changes in V4 and V5:
None
Changes in V3:
Add Frank's rev'd-by
Changes in V2:
Improve commit message
drivers/i3c/master/mipi-i3c-hci/dma.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/i3c/master/mipi-i3c-hci/dma.c b/drivers/i3c/master/mipi-i3c-hci/dma.c
index e4daaa612055..bdffdd8b8923 100644
--- 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) {
--
2.51.0
--
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