[PATCH 11/26] drm/rockchip: dw-mipi-dsi: don't assume buffer is aligned

John Keeping
2016-09-19T17:17:21Z

By dereferencing the MIPI command buffer as a u32* we rely on it being
correctly aligned on ARM, but this may not be the case. Copy it into a
stack variable that will be correctly aligned.

Signed-off-by: John Keeping <john@metanate.com>
---
drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
index ed2da1bbada9..4c945cc4d31a 100644
--- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
@@ -608,10 +608,10 @@ static int dw_mipi_dsi_dcs_short_write(struct dw_mipi_dsi *dsi,
static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi,
const struct mipi_dsi_msg *msg)
{
- const u32 *tx_buf = msg->tx_buf;
- int len = msg->tx_len, pld_data_bytes = sizeof(*tx_buf), ret;
+ const u8 *tx_buf = msg->tx_buf;
+ int len = msg->tx_len, pld_data_bytes = sizeof(u32), ret;
u32 hdr_val = GEN_HDATA(msg->tx_len) | GEN_HTYPE(msg->type);
- u32 remainder = 0;
+ u32 remainder;
u32 val;

if (msg->tx_len < 3) {
@@ -622,12 +622,14 @@ static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi,

while (DIV_ROUND_UP(len, pld_data_bytes)) {
if (len < pld_data_bytes) {
+ remainder = 0;
memcpy(&remainder, tx_buf, len);
dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
len = 0;
} else {
- dsi_write(dsi, DSI_GEN_PLD_DATA, *tx_buf);
- tx_buf++;
+ memcpy(&remainder, tx_buf, pld_data_bytes);
+ dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
+ tx_buf += pld_data_bytes;
len -= pld_data_bytes;
}

--
2.10.0.278.g4f427b1.dirty