[PATCH 16/16] i3c: mipi-i3c-hci: Increase DMA transfer ring size to maximum

[Adrian Hunter]

The DMA transfer ring is currently limited to 16 entries, despite the
MIPI I3C HCI supporting up to 32 devices.  When the ring lacks space for a
new transfer list, the driver returns -EBUSY, which can be unexpected
for clients.

Increase the DMA transfer ring size to the maximum supported value of
255 entries.  This effectively eliminates ring-space exhaustion in
practice and avoids the complexity of adding secondary queuing
mechanisms.

Even at the maximum size, the memory overhead remains small
(approximately 24 bytes per entry by default).

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
 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 b06405a9aa7b..fdab1e2df19c 100644
--- a/drivers/i3c/master/mipi-i3c-hci/dma.c
+++ b/drivers/i3c/master/mipi-i3c-hci/dma.c
@@ -27,7 +27,7 @@
  */
 
 #define XFER_RINGS			1	/* max: 8 */
-#define XFER_RING_ENTRIES		16	/* max: 255 */
+#define XFER_RING_ENTRIES		255	/* max: 255 */
 
 #define IBI_RINGS			1	/* max: 8 */
 #define IBI_STATUS_RING_ENTRIES		32	/* max: 255 */
-- 
2.51.0