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Date: Thu, 24 Jan 2019 12:51:51 -0800
From: Sowjanya Komatineni <skomatineni@...dia.com>
To: <thierry.reding@...il.com>, <jonathanh@...dia.com>,
<mkarthik@...dia.com>, <smohammed@...dia.com>, <talho@...dia.com>
CC: <linux-tegra@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linux-i2c@...r.kernel.org>,
Sowjanya Komatineni <skomatineni@...dia.com>
Subject: [PATCH V2 2/4] i2c: tegra: Update I2C transfer using buffer
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@...dia.com>
---
[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
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