[PATCH 5.4 016/132] drm/sun4i: Fix dsi dcs long write function

Greg Kroah-Hartman
2020-09-16T00:14:05Z

From: Ondrej Jirman <megous@megous.com>

[ Upstream commit fd90e3808fd2c207560270c39b86b71af2231aa1 ]

It's writing too much data. regmap_bulk_write expects number of
register sized chunks to write, not a byte sized length of the
bounce buffer. Bounce buffer needs to be padded too, so that
regmap_bulk_write will not read past the end of the buffer.

Fixes: 133add5b5ad4 ("drm/sun4i: Add Allwinner A31 MIPI-DSI controller support")
Signed-off-by: Ondrej Jirman <megous@megous.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Jernej Skrabec <jernej.skrabec@siol.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200828125032.937148-1-megous@megous.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
index 4f944ace665d5..f2b288037b909 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
@@ -867,7 +867,7 @@ static int sun6i_dsi_dcs_write_long(struct sun6i_dsi *dsi,
regmap_write(dsi->regs, SUN6I_DSI_CMD_TX_REG(0),
sun6i_dsi_dcs_build_pkt_hdr(dsi, msg));

- bounce = kzalloc(msg->tx_len + sizeof(crc), GFP_KERNEL);
+ bounce = kzalloc(ALIGN(msg->tx_len + sizeof(crc), 4), GFP_KERNEL);
if (!bounce)
return -ENOMEM;

@@ -878,7 +878,7 @@ static int sun6i_dsi_dcs_write_long(struct sun6i_dsi *dsi,
memcpy((u8 *)bounce + msg->tx_len, &crc, sizeof(crc));
len += sizeof(crc);

- regmap_bulk_write(dsi->regs, SUN6I_DSI_CMD_TX_REG(1), bounce, len);
+ regmap_bulk_write(dsi->regs, SUN6I_DSI_CMD_TX_REG(1), bounce, DIV_ROUND_UP(len, 4));
regmap_write(dsi->regs, SUN6I_DSI_CMD_CTL_REG, len + 4 - 1);
kfree(bounce);

--
2.25.1