i3c: master: svc: Use readsb helper for reading MDB

commit c06acf7143bddaa3c0f7bedd8b99e48f6acb85c3 upstream.

The target can send the MDB byte followed by additional data bytes.
The readl on MRDATAB reads one actual byte, but the readsl advances
the destination pointer by 4 bytes. This causes the subsequent payload
to be copied to wrong position in the destination buffer.

Cc: stable@kernel.org
Fixes: dd3c52846d59 ("i3c: master: svc: Add Silvaco I3C master driver")
Signed-off-by: Stanley Chu <yschu@nuvoton.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20250318053606.3087121-3-yschu@nuvoton.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index 87f98fa8afd582fe3f3f3f0f286196ce49207d70..42102baabcddadf9b1b9675019bee99798be8fda 100644 (file)
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -378,7 +378,7 @@ static int svc_i3c_master_handle_ibi(struct svc_i3c_master *master,
               slot->len < SVC_I3C_FIFO_SIZE) {
                mdatactrl = readl(master->regs + SVC_I3C_MDATACTRL);
                count = SVC_I3C_MDATACTRL_RXCOUNT(mdatactrl);
-               readsl(master->regs + SVC_I3C_MRDATAB, buf, count);
+               readsb(master->regs + SVC_I3C_MRDATAB, buf, count);
                slot->len += count;
                buf += count;
        }