[PATCH] i2c: mediatek: modify threshold passed to i2c_get_dma_safe_msg_buf()

Hsin-Yi Wang
2019-02-15T09:02:37Z

i2c_get_dma_safe_msg_buf() allocates space based on msg->len. If threshold is
0 and msg->len is also 0, function makes zero-length allocation, which returns
a special ZERO_SIZE_PTR instead of a NULL pointer, and this will cause later
code to fail. Modify the threshold to > 0 so the function returns NULL pointer.

Fixes: fc66b39fe36a ("i2c: mediatek: Use DMA safe buffers for i2c transactions")
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
---
drivers/i2c/busses/i2c-mt65xx.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
index a74ef76705e0..2bb4d20ead32 100644
--- a/drivers/i2c/busses/i2c-mt65xx.c
+++ b/drivers/i2c/busses/i2c-mt65xx.c
@@ -503,7 +503,7 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
writel(I2C_DMA_INT_FLAG_NONE, i2c->pdmabase + OFFSET_INT_FLAG);
writel(I2C_DMA_CON_RX, i2c->pdmabase + OFFSET_CON);

- dma_rd_buf = i2c_get_dma_safe_msg_buf(msgs, 0);
+ dma_rd_buf = i2c_get_dma_safe_msg_buf(msgs, 1);
if (!dma_rd_buf)
return -ENOMEM;

@@ -526,7 +526,7 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
writel(I2C_DMA_INT_FLAG_NONE, i2c->pdmabase + OFFSET_INT_FLAG);
writel(I2C_DMA_CON_TX, i2c->pdmabase + OFFSET_CON);

- dma_wr_buf = i2c_get_dma_safe_msg_buf(msgs, 0);
+ dma_wr_buf = i2c_get_dma_safe_msg_buf(msgs, 1);
if (!dma_wr_buf)
return -ENOMEM;

@@ -549,7 +549,7 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_INT_FLAG);
writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_CON);

- dma_wr_buf = i2c_get_dma_safe_msg_buf(msgs, 0);
+ dma_wr_buf = i2c_get_dma_safe_msg_buf(msgs, 1);
if (!dma_wr_buf)
return -ENOMEM;

@@ -561,7 +561,7 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
return -ENOMEM;
}

- dma_rd_buf = i2c_get_dma_safe_msg_buf((msgs + 1), 0);
+ dma_rd_buf = i2c_get_dma_safe_msg_buf((msgs + 1), 1);
if (!dma_rd_buf) {
dma_unmap_single(i2c->dev, wpaddr,
msgs->len, DMA_TO_DEVICE);
--
2.18.1