drm: bridge: samsung-dsim: Drain command transfer FIFO before transfer
authorMarek Vasut <marex@denx.de>
Thu, 15 Jun 2023 20:15:11 +0000 (22:15 +0200)
committerMarek Vasut <marex@denx.de>
Sun, 2 Jul 2023 00:58:21 +0000 (02:58 +0200)
Wait until the command transfer FIFO is empty before loading in the next
command. The previous behavior where the code waited until command transfer
FIFO was not full suffered from transfer corruption, where the last command
in the FIFO could be overwritten in case the FIFO indicates not full, but
also does not have enough space to store another transfer yet.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com> # imx8mm-icore
Link: https://patchwork.freedesktop.org/patch/msgid/20230615201511.565923-1-marex@denx.de
drivers/gpu/drm/bridge/samsung-dsim.c

index 043b810..9b7a00b 100644 (file)
@@ -1009,7 +1009,7 @@ static int samsung_dsim_wait_for_hdr_fifo(struct samsung_dsim *dsi)
        do {
                u32 reg = samsung_dsim_read(dsi, DSIM_FIFOCTRL_REG);
 
-               if (!(reg & DSIM_SFR_HEADER_FULL))
+               if (reg & DSIM_SFR_HEADER_EMPTY)
                        return 0;
 
                if (!cond_resched())