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[PATCH v4 10/23] drm/rockchip: dw-mipi-dsi: don't assume buffer is aligned

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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>
Reviewed-by: Chris Zhong <zyw@rock-chips.com>
---
v3:
- Add Chris' Reviewed-by
Unchanged in v2
---
 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 1b6fce2600f3..0c66e6eaf44a 100644
--- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
@@ -609,10 +609,10 @@ 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) {
@@ -623,12 +623,14 @@ 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;
 		}
 
-- 
2.12.0.rc0.230.gf625d4cdb9.dirty

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[PATCH v4 00/23] drm/rockchip: MIPI fixes & improvements John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 18/23] drm/rockchip: dw-mipi-dsi: use specific poll helper John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 13/23] drm/rockchip: dw-mipi-dsi: fix escape clock rate John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 23/23] drm/rockchip: dw-mipi-dsi: add reset control John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 12/23] drm/rockchip: dw-mipi-dsi: allow commands in panel_disable John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 02/23] drm/rockchip: dw-mipi-dsi: pass mode in where needed John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 07/23] drm/rockchip: dw-mipi-dsi: include bad value in error message John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 21/23] drm/rockchip: dw-mipi-dsi: defer probe if panel is not loaded John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 19/23] drm/rockchip: dw-mipi-dsi: use positive check for N{H,V}SYNC John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 06/23] drm/rockchip: dw-mipi-dsi: avoid out-of-bounds read on tx_buf John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 15/23] drm/rockchip: dw-mipi-dsi: configure PHY before enabling John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 08/23] drm/rockchip: dw-mipi-dsi: respect message flags John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 04/23] drm/rockchip: dw-mipi-dsi: fix command header writes John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 10/23] drm/rockchip: dw-mipi-dsi: don't assume buffer is aligned John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 11/23] drm/rockchip: dw-mipi-dsi: prepare panel after phy init John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 17/23] drm/rockchip: dw-mipi-dsi: improve PLL configuration John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 09/23] drm/rockchip: dw-mipi-dsi: only request HS clock when required John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 03/23] drm/rockchip: dw-mipi-dsi: remove mode_set hook John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 05/23] drm/rockchip: dw-mipi-dsi: fix generic packet status check John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 01/23] drm/rockchip: dw-mipi-dsi: don't configure hardware in mode_set for MIPI John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 16/23] drm/rockchip: dw-mipi-dsi: properly configure PHY timing John Keeping <john@metanate.com> - 2017-02-24 14:00 +0100
  [PATCH v4 22/23] drm/rockchip: dw-mipi-dsi: support non-burst modes John Keeping <john@metanate.com> - 2017-02-24 14:10 +0100
  Re: [PATCH v4 00/23] drm/rockchip: MIPI fixes & improvements Mark yao <mark.yao@rock-chips.com> - 2017-02-27 02:50 +0100
  Re: [PATCH v4 00/23] drm/rockchip: MIPI fixes & improvements Chris Zhong <zyw@rock-chips.com> - 2017-02-27 04:40 +0100

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