1 files changed, 29 insertions, 9 deletions

diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
index e95f9ba96790..917d54588d95 100644
--- a/drivers/i2c/busses/i2c-at91.c
+++ b/drivers/i2c/busses/i2c-at91.c
@@ -101,6 +101,7 @@ struct at91_twi_dev {
 	unsigned twi_cwgr_reg;
 	struct at91_twi_pdata *pdata;
 	bool use_dma;
+	bool recv_len_abort;
 	struct at91_twi_dma dma;
 };
 
@@ -210,7 +211,7 @@ static void at91_twi_write_data_dma_callback(void *data)
 	struct at91_twi_dev *dev = (struct at91_twi_dev *)data;
 
 	dma_unmap_single(dev->dev, sg_dma_address(&dev->dma.sg),
-			 dev->buf_len, DMA_MEM_TO_DEV);
+			 dev->buf_len, DMA_TO_DEVICE);
 
 	at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
 }
@@ -267,12 +268,24 @@ static void at91_twi_read_next_byte(struct at91_twi_dev *dev)
 	*dev->buf = at91_twi_read(dev, AT91_TWI_RHR) & 0xff;
 	--dev->buf_len;
 
+	/* return if aborting, we only needed to read RHR to clear RXRDY*/
+	if (dev->recv_len_abort)
+		return;
+
 	/* handle I2C_SMBUS_BLOCK_DATA */
 	if (unlikely(dev->msg->flags & I2C_M_RECV_LEN)) {
-		dev->msg->flags &= ~I2C_M_RECV_LEN;
-		dev->buf_len += *dev->buf;
-		dev->msg->len = dev->buf_len + 1;
-		dev_dbg(dev->dev, "received block length %d\n", dev->buf_len);
+		/* ensure length byte is a valid value */
+		if (*dev->buf <= I2C_SMBUS_BLOCK_MAX && *dev->buf > 0) {
+			dev->msg->flags &= ~I2C_M_RECV_LEN;
+			dev->buf_len += *dev->buf;
+			dev->msg->len = dev->buf_len + 1;
+			dev_dbg(dev->dev, "received block length %d\n",
+					 dev->buf_len);
+		} else {
+			/* abort and send the stop by reading one more byte */
+			dev->recv_len_abort = true;
+			dev->buf_len = 1;
+		}
 	}
 
 	/* send stop if second but last byte has been read */
@@ -289,7 +302,7 @@ static void at91_twi_read_data_dma_callback(void *data)
 	struct at91_twi_dev *dev = (struct at91_twi_dev *)data;
 
 	dma_unmap_single(dev->dev, sg_dma_address(&dev->dma.sg),
-			 dev->buf_len, DMA_DEV_TO_MEM);
+			 dev->buf_len, DMA_FROM_DEVICE);
 
 	/* The last two bytes have to be read without using dma */
 	dev->buf += dev->buf_len - 2;
@@ -421,8 +434,8 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev)
 		}
 	}
 
-	ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
-							dev->adapter.timeout);
+	ret = wait_for_completion_io_timeout(&dev->cmd_complete,
+					     dev->adapter.timeout);
 	if (ret == 0) {
 		dev_err(dev->dev, "controller timed out\n");
 		at91_init_twi_bus(dev);
@@ -444,6 +457,12 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev)
 		ret = -EIO;
 		goto error;
 	}
+	if (dev->recv_len_abort) {
+		dev_err(dev->dev, "invalid smbus block length recvd\n");
+		ret = -EPROTO;
+		goto error;
+	}
+
 	dev_dbg(dev->dev, "transfer complete\n");
 
 	return 0;
@@ -500,6 +519,7 @@ static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
 	dev->buf_len = m_start->len;
 	dev->buf = m_start->buf;
 	dev->msg = m_start;
+	dev->recv_len_abort = false;
 
 	ret = at91_do_twi_transfer(dev);
 
@@ -768,7 +788,7 @@ static int at91_twi_probe(struct platform_device *pdev)
 	snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91");
 	i2c_set_adapdata(&dev->adapter, dev);
 	dev->adapter.owner = THIS_MODULE;
-	dev->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_DEPRECATED;
+	dev->adapter.class = I2C_CLASS_DEPRECATED;
 	dev->adapter.algo = &at91_twi_algorithm;
 	dev->adapter.dev.parent = dev->dev;
 	dev->adapter.nr = pdev->id;