[PATCH v9 23/32] i2c: tegra: Factor out packet header setup from tegra_i2c_xfer_msg()

[Dmitry Osipenko]

The code related to packet header setting up is a bit messy and makes
tegra_i2c_xfer_msg() more difficult to read than it could be. Let's
factor the packet header setup from tegra_i2c_xfer_msg() into separate
function in order to make code easier to read and follow.

Reviewed-by: Michał Mirosław <mirq-linux@xxxxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Acked-by: Thierry Reding <treding@xxxxxxxxxx>
Tested-by: Thierry Reding <treding@xxxxxxxxxx>
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
 drivers/i2c/busses/i2c-tegra.c | 95 ++++++++++++++++++++--------------
 1 file changed, 55 insertions(+), 40 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 95d257cbd800..fbeae872ece1 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -281,7 +281,7 @@ struct tegra_i2c_dev {
 	struct dma_chan *tx_dma_chan;
 	struct dma_chan *rx_dma_chan;
 	dma_addr_t dma_phys;
-	u32 *dma_buf;
+	void *dma_buf;
 	unsigned int dma_buf_size;
 	bool is_curr_dma_xfer;
 	struct completion dma_complete;
@@ -1105,6 +1105,57 @@ static int tegra_i2c_issue_bus_clear(struct i2c_adapter *adap)
 	return -EAGAIN;
 }
 
+static void tegra_i2c_push_packet_header(struct tegra_i2c_dev *i2c_dev,
+					 struct i2c_msg *msg,
+					 enum msg_end_type end_state)
+{
+	u32 *dma_buf = i2c_dev->dma_buf;
+	u32 packet_header;
+
+	packet_header = FIELD_PREP(PACKET_HEADER0_HEADER_SIZE, 0) |
+			FIELD_PREP(PACKET_HEADER0_PROTOCOL,
+				   PACKET_HEADER0_PROTOCOL_I2C) |
+			FIELD_PREP(PACKET_HEADER0_CONT_ID, i2c_dev->cont_id) |
+			FIELD_PREP(PACKET_HEADER0_PACKET_ID, 1);
+
+	if (i2c_dev->is_curr_dma_xfer && !i2c_dev->msg_read)
+		*dma_buf++ = packet_header;
+	else
+		i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
+
+	packet_header = msg->len - 1;
+
+	if (i2c_dev->is_curr_dma_xfer && !i2c_dev->msg_read)
+		*dma_buf++ = packet_header;
+	else
+		i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
+
+	packet_header = I2C_HEADER_IE_ENABLE;
+
+	if (end_state == MSG_END_CONTINUE)
+		packet_header |= I2C_HEADER_CONTINUE_XFER;
+	else if (end_state == MSG_END_REPEAT_START)
+		packet_header |= I2C_HEADER_REPEAT_START;
+
+	if (msg->flags & I2C_M_TEN) {
+		packet_header |= msg->addr;
+		packet_header |= I2C_HEADER_10BIT_ADDR;
+	} else {
+		packet_header |= msg->addr << I2C_HEADER_SLAVE_ADDR_SHIFT;
+	}
+
+	if (msg->flags & I2C_M_IGNORE_NAK)
+		packet_header |= I2C_HEADER_CONT_ON_NAK;
+
+	if (msg->flags & I2C_M_RD)
+		packet_header |= I2C_HEADER_READ;
+
+	if (i2c_dev->is_curr_dma_xfer && !i2c_dev->msg_read)
+		*dma_buf++ = packet_header;
+	else
+		i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
+}
+
 static int tegra_i2c_error_recover(struct tegra_i2c_dev *i2c_dev,
 				   struct i2c_msg *msg)
 {
@@ -1135,11 +1186,9 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 			      struct i2c_msg *msg,
 			      enum msg_end_type end_state)
 {
-	u32 packet_header;
 	u32 int_mask;
 	unsigned long time_left;
 	size_t xfer_size;
-	u32 *buffer = NULL;
 	int err = 0;
 	u16 xfer_time = 100;
 
@@ -1192,49 +1241,15 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 						i2c_dev->dma_phys,
 						xfer_size,
 						DMA_TO_DEVICE);
-			buffer = i2c_dev->dma_buf;
 		}
 	}
 
-	packet_header = FIELD_PREP(PACKET_HEADER0_HEADER_SIZE, 0) |
-			FIELD_PREP(PACKET_HEADER0_PROTOCOL,
-				   PACKET_HEADER0_PROTOCOL_I2C) |
-			FIELD_PREP(PACKET_HEADER0_CONT_ID, i2c_dev->cont_id) |
-			FIELD_PREP(PACKET_HEADER0_PACKET_ID, 1);
-	if (i2c_dev->is_curr_dma_xfer && !i2c_dev->msg_read)
-		*buffer++ = packet_header;
-	else
-		i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
-
-	packet_header = msg->len - 1;
-	if (i2c_dev->is_curr_dma_xfer && !i2c_dev->msg_read)
-		*buffer++ = packet_header;
-	else
-		i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
-
-	packet_header = I2C_HEADER_IE_ENABLE;
-	if (end_state == MSG_END_CONTINUE)
-		packet_header |= I2C_HEADER_CONTINUE_XFER;
-	else if (end_state == MSG_END_REPEAT_START)
-		packet_header |= I2C_HEADER_REPEAT_START;
-	if (msg->flags & I2C_M_TEN) {
-		packet_header |= msg->addr;
-		packet_header |= I2C_HEADER_10BIT_ADDR;
-	} else {
-		packet_header |= msg->addr << I2C_HEADER_SLAVE_ADDR_SHIFT;
-	}
-	if (msg->flags & I2C_M_IGNORE_NAK)
-		packet_header |= I2C_HEADER_CONT_ON_NAK;
-	if (msg->flags & I2C_M_RD)
-		packet_header |= I2C_HEADER_READ;
-	if (i2c_dev->is_curr_dma_xfer && !i2c_dev->msg_read)
-		*buffer++ = packet_header;
-	else
-		i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
+	tegra_i2c_push_packet_header(i2c_dev, msg, end_state);
 
 	if (!i2c_dev->msg_read) {
 		if (i2c_dev->is_curr_dma_xfer) {
-			memcpy(buffer, msg->buf, msg->len);
+			memcpy(i2c_dev->dma_buf + I2C_PACKET_HEADER_SIZE,
+			       msg->buf, msg->len);
 			dma_sync_single_for_device(i2c_dev->dev,
 						   i2c_dev->dma_phys,
 						   xfer_size,
-- 
2.27.0