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i2c-davinci: Fix signal handling bug

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If wait_for_completion_interruptible_timeout exits due
to a signal, the i2c bus was locking up.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Signed-off-by: Kevin Hilman <khilman@mvista.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
This commit is contained in:
Troy Kisky 2008-07-14 22:38:21 +02:00 committed by Jean Delvare
parent 0ab56e2067
commit 5a0d5f5ffa
1 changed files with 52 additions and 10 deletions
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62
drivers/i2c/busses/i2c-davinci.c
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@ -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))
@ -354,6 +370,27 @@ 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.
@ -374,12 +411,15 @@ 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;
@ -401,9 +441,10 @@ 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:
@ -420,9 +461,10 @@ 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: