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Commit fcae73fa authored by Mats Randgaard's avatar Mats Randgaard Committed by Mauro Carvalho Chehab
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[media] tc358743: Use local array with fixed size in i2c write 



i2c_wr() is called from ops and the interrupt service routine, while
state->wr_data is shared and unprotected, and could be overwritten.

This shared buffer is therefore replaced with a local array with fixed
size. The array has the size of one EDID block (128 bytes) + 2 bytes
i2c address, and the EDID is written block by block (up to 8 blocks).

Signed-off-by: default avatarMats Randgaard <matrandg@cisco.com>
Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@osg.samsung.com>
parent 8e20b803

drivers/media/i2c/tc358743.c

+8 −8
Original line number Diff line number Diff line
@@ -59,8 +59,7 @@ MODULE_LICENSE("GPL"); 
#define EDID_NUM_BLOCKS_MAX 8

#define EDID_BLOCK_SIZE 128



/* Max transfer size done by I2C transfer functions */

#define MAX_XFER_SIZE  (EDID_NUM_BLOCKS_MAX * EDID_BLOCK_SIZE + 2)

#define I2C_MAX_XFER_SIZE  (EDID_BLOCK_SIZE + 2)



static const struct v4l2_dv_timings_cap tc358743_timings_cap = {

	.type = V4L2_DV_BT_656_1120,
@@ -97,9 +96,6 @@ struct tc358743_state { 
	/* edid  */

	u8 edid_blocks_written;



	/* used by i2c_wr() */

	u8 wr_data[MAX_XFER_SIZE];



	struct v4l2_dv_timings timings;

	u32 mbus_fmt_code;
@@ -149,13 +145,15 @@ static void i2c_wr(struct v4l2_subdev *sd, u16 reg, u8 *values, u32 n) 
{

	struct tc358743_state *state = to_state(sd);

	struct i2c_client *client = state->i2c_client;

	u8 *data = state->wr_data;

	int err, i;

	struct i2c_msg msg;

	u8 data[I2C_MAX_XFER_SIZE];



	if ((2 + n) > sizeof(state->wr_data))

	if ((2 + n) > I2C_MAX_XFER_SIZE) {

		n = I2C_MAX_XFER_SIZE - 2;

		v4l2_warn(sd, "i2c wr reg=%04x: len=%d is too big!\n",

			  reg, 2 + n);

	}



	msg.addr = client->addr;

	msg.buf = data;
@@ -1582,6 +1580,7 @@ static int tc358743_s_edid(struct v4l2_subdev *sd, 
{

	struct tc358743_state *state = to_state(sd);

	u16 edid_len = edid->blocks * EDID_BLOCK_SIZE;

	int i;



	v4l2_dbg(2, debug, sd, "%s, pad %d, start block %d, blocks %d\n",

		 __func__, edid->pad, edid->start_block, edid->blocks);
@@ -1607,7 +1606,8 @@ static int tc358743_s_edid(struct v4l2_subdev *sd, 
		return 0;

	}



	i2c_wr(sd, EDID_RAM, edid->edid, edid_len);

	for (i = 0; i < edid_len; i += EDID_BLOCK_SIZE)

		i2c_wr(sd, EDID_RAM + i, edid->edid + i, EDID_BLOCK_SIZE);



	state->edid_blocks_written = edid->blocks;