This patch prepares the buffer with the message bytes to be
transmitted along with the packet header information and then
performs i2c transfer in PIO mode.
Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
---
[V2] : DMA support changes include preparing buffer with message bytes and
and header before sending them through DMA. So splitted the whole
change into 2 seperate patches in this series.
drivers/i2c/busses/i2c-tegra.c | 97 +++++++++++++++++++++++++++++-------------
1 file changed, 68 insertions(+), 29 deletions(-)
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index ef854be4c837..13bce1411ddc 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -117,6 +117,9 @@
#define I2C_MST_FIFO_STATUS_TX_MASK 0xff0000
#define I2C_MST_FIFO_STATUS_TX_SHIFT 16
+/* Packet header size in bytes */
+#define I2C_PACKET_HEADER_SIZE 12
+
/*
* msg_end_type: The bus control which need to be send at end of transfer.
* @MSG_END_STOP: Send stop pulse at end of transfer.
@@ -677,35 +680,69 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
return IRQ_HANDLED;
}
+static int tegra_i2c_start_pio_xfer(struct tegra_i2c_dev *i2c_dev)
+{
+ u32 *buffer = (u32 *)i2c_dev->msg_buf;
+ unsigned long flags;
+ u32 int_mask;
+
+ spin_lock_irqsave(&i2c_dev->xfer_lock, flags);
+
+ int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
+ tegra_i2c_unmask_irq(i2c_dev, int_mask);
+
+ i2c_writel(i2c_dev, *(buffer++), I2C_TX_FIFO);
+ i2c_writel(i2c_dev, *(buffer++), I2C_TX_FIFO);
+ i2c_writel(i2c_dev, *(buffer++), I2C_TX_FIFO);
+
+ i2c_dev->msg_buf = (u8 *) buffer;
+
+ if (!i2c_dev->msg_read)
+ tegra_i2c_fill_tx_fifo(i2c_dev);
+
+ if (i2c_dev->hw->has_per_pkt_xfer_complete_irq)
+ int_mask |= I2C_INT_PACKET_XFER_COMPLETE;
+ if (i2c_dev->msg_read)
+ int_mask |= I2C_INT_RX_FIFO_DATA_REQ;
+ else if (i2c_dev->msg_buf_remaining)
+ int_mask |= I2C_INT_TX_FIFO_DATA_REQ;
+
+ tegra_i2c_unmask_irq(i2c_dev, int_mask);
+ spin_unlock_irqrestore(&i2c_dev->xfer_lock, flags);
+ dev_dbg(i2c_dev->dev, "unmasked irq: %02x\n",
+ i2c_readl(i2c_dev, I2C_INT_MASK));
+
+ return 0;
+}
+
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;
- unsigned long flags;
+ u32 *buffer;
+ int ret = 0;
+
+ buffer = kmalloc(ALIGN(msg->len, BYTES_PER_FIFO_WORD) +
+ I2C_PACKET_HEADER_SIZE, GFP_KERNEL);
+ if (!buffer)
+ return -ENOMEM;
tegra_i2c_flush_fifos(i2c_dev);
- i2c_dev->msg_buf = msg->buf;
+ i2c_dev->msg_buf = (u8 *)buffer;
i2c_dev->msg_buf_remaining = msg->len;
i2c_dev->msg_err = I2C_ERR_NONE;
i2c_dev->msg_read = (msg->flags & I2C_M_RD);
reinit_completion(&i2c_dev->msg_complete);
- spin_lock_irqsave(&i2c_dev->xfer_lock, flags);
-
- int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
- tegra_i2c_unmask_irq(i2c_dev, int_mask);
-
- packet_header = (0 << PACKET_HEADER0_HEADER_SIZE_SHIFT) |
+ (*buffer++) = (0 << PACKET_HEADER0_HEADER_SIZE_SHIFT) |
PACKET_HEADER0_PROTOCOL_I2C |
(i2c_dev->cont_id << PACKET_HEADER0_CONT_ID_SHIFT) |
(1 << PACKET_HEADER0_PACKET_ID_SHIFT);
- i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
- packet_header = msg->len - 1;
- i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
+ (*buffer++) = msg->len - 1;
packet_header = I2C_HEADER_IE_ENABLE;
if (end_state == MSG_END_CONTINUE)
@@ -722,34 +759,31 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
packet_header |= I2C_HEADER_CONT_ON_NAK;
if (msg->flags & I2C_M_RD)
packet_header |= I2C_HEADER_READ;
- i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
+ *(buffer++) = packet_header;
if (!(msg->flags & I2C_M_RD))
- tegra_i2c_fill_tx_fifo(i2c_dev);
-
- if (i2c_dev->hw->has_per_pkt_xfer_complete_irq)
- int_mask |= I2C_INT_PACKET_XFER_COMPLETE;
- if (msg->flags & I2C_M_RD)
- int_mask |= I2C_INT_RX_FIFO_DATA_REQ;
- else if (i2c_dev->msg_buf_remaining)
- int_mask |= I2C_INT_TX_FIFO_DATA_REQ;
+ memcpy(buffer, msg->buf, msg->len);
- tegra_i2c_unmask_irq(i2c_dev, int_mask);
- spin_unlock_irqrestore(&i2c_dev->xfer_lock, flags);
- dev_dbg(i2c_dev->dev, "unmasked irq: %02x\n",
- i2c_readl(i2c_dev, I2C_INT_MASK));
+ tegra_i2c_start_pio_xfer(i2c_dev);
time_left = wait_for_completion_timeout(&i2c_dev->msg_complete,
TEGRA_I2C_TIMEOUT);
- tegra_i2c_mask_irq(i2c_dev, int_mask);
-
if (time_left == 0) {
dev_err(i2c_dev->dev, "i2c transfer timed out\n");
tegra_i2c_init(i2c_dev);
- return -ETIMEDOUT;
+ ret = -ETIMEDOUT;
+ goto err_xfer;
+ }
+
+ if (i2c_dev->msg_read) {
+ i2c_dev->msg_buf = (u8 *)buffer;
+ memcpy(msg->buf, i2c_dev->msg_buf, msg->len);
}
+ int_mask = i2c_readl(i2c_dev, I2C_INT_MASK);
+ tegra_i2c_mask_irq(i2c_dev, int_mask);
+
dev_dbg(i2c_dev->dev, "transfer complete: %lu %d %d\n",
time_left, completion_done(&i2c_dev->msg_complete),
i2c_dev->msg_err);
@@ -761,10 +795,15 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
if (i2c_dev->msg_err == I2C_ERR_NO_ACK) {
if (msg->flags & I2C_M_IGNORE_NAK)
return 0;
- return -EREMOTEIO;
+ ret = -EREMOTEIO;
+ goto err_xfer;
}
- return -EIO;
+ ret = -EIO;
+
+err_xfer:
+ kfree(buffer);
+ return ret;
}
static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
--
2.7.4
