If wait_for_completion_interruptible_timeout exits due
to a signal, the i2c bus was locking up.
Signed-off-by: Troy Kisky <[EMAIL PROTECTED]>
Signed-off-by: Kevin Hilman <[EMAIL PROTECTED]>
---
drivers/i2c/busses/i2c-davinci.c | 62 +++++++++++++++++++++++++++++++------
1 files changed, 52 insertions(+), 10 deletions(-)
diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 77c9822..c44ef4a 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -85,6 +85,7 @@
#define DAVINCI_I2C_MDR_MST (1 << 10)
#define DAVINCI_I2C_MDR_TRX (1 << 9)
#define DAVINCI_I2C_MDR_XA (1 << 8)
+#define DAVINCI_I2C_MDR_RM (1 << 7)
#define DAVINCI_I2C_MDR_IRS (1 << 5)
#define DAVINCI_I2C_IMR_AAS (1 << 6)
@@ -112,6 +113,7 @@ struct davinci_i2c_dev {
u8 *buf;
size_t buf_len;
int irq;
+ u8 terminate;
struct i2c_adapter adapter;
};
@@ -283,20 +285,34 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct
i2c_msg *msg, int stop)
MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 1);
davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
+ dev->terminate = 0;
/* write the data into mode register */
davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
r = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
DAVINCI_I2C_TIMEOUT);
- dev->buf_len = 0;
- if (r < 0)
- return r;
-
if (r == 0) {
dev_err(dev->dev, "controller timed out\n");
i2c_davinci_init(dev);
+ dev->buf_len = 0;
return -ETIMEDOUT;
}
+ if (dev->buf_len) {
+ /* This should be 0 if all bytes were transferred
+ * or dev->cmd_err denotes an error.
+ * A signal may have aborted the transfer.
+ */
+ if (r >= 0) {
+ dev_err(dev->dev, "abnormal termination buf_len=%i\n",
+ dev->buf_len);
+ r = -EREMOTEIO;
+ }
+ dev->terminate = 1;
+ wmb();
+ dev->buf_len = 0;
+ }
+ if (r < 0)
+ return r;
/* no error */
if (likely(!dev->cmd_err))
@@ -353,6 +369,27 @@ static u32 i2c_davinci_func(struct i2c_adapter *adap)
return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
}
+static void terminate_read(struct davinci_i2c_dev *dev)
+{
+ u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
+ w |= DAVINCI_I2C_MDR_NACK;
+ davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
+
+ /* Throw away data */
+ davinci_i2c_read_reg(dev, DAVINCI_I2C_DRR_REG);
+ if (!dev->terminate)
+ dev_err(dev->dev, "RDR IRQ while no data requested\n");
+}
+static void terminate_write(struct davinci_i2c_dev *dev)
+{
+ u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
+ w |= DAVINCI_I2C_MDR_RM | DAVINCI_I2C_MDR_STP;
+ davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
+
+ if (!dev->terminate)
+ dev_err(dev->dev, "TDR IRQ while no data to send\n");
+}
+
/*
* Interrupt service routine. This gets called whenever an I2C interrupt
* occurs.
@@ -373,12 +410,15 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void
*dev_id)
switch (stat) {
case DAVINCI_I2C_IVR_AL:
+ /* Arbitration lost, must retry */
dev->cmd_err |= DAVINCI_I2C_STR_AL;
+ dev->buf_len = 0;
complete(&dev->cmd_complete);
break;
case DAVINCI_I2C_IVR_NACK:
dev->cmd_err |= DAVINCI_I2C_STR_NACK;
+ dev->buf_len = 0;
complete(&dev->cmd_complete);
break;
@@ -400,9 +440,10 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void
*dev_id)
davinci_i2c_write_reg(dev,
DAVINCI_I2C_STR_REG,
DAVINCI_I2C_IMR_RRDY);
- } else
- dev_err(dev->dev, "RDR IRQ while no "
- "data requested\n");
+ } else {
+ /* signal can terminate transfer */
+ terminate_read(dev);
+ }
break;
case DAVINCI_I2C_IVR_XRDY:
@@ -419,9 +460,10 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void
*dev_id)
davinci_i2c_write_reg(dev,
DAVINCI_I2C_IMR_REG,
w);
- } else
- dev_err(dev->dev, "TDR IRQ while no data to "
- "send\n");
+ } else {
+ /* signal can terminate transfer */
+ terminate_write(dev);
+ }
break;
case DAVINCI_I2C_IVR_SCD:
--
1.5.4
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