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[PATCH] i2c: i2c-mv64xxx fix transaction abortion 

When the i2c-mv64xxx i2c driver is signalled to abort a transaction,
it aborts it immediately by issuing a stop condition on the bus.
This violates the i2c protocol and can cause what appears to be an i2c
bus hang.  This patch delays issuing the stop condition until the i2c
device can reasonably expect a stop condition.

Also includes a minor fixup.

Signed-off-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
This commit is contained in:
Mark A. Greer 2005-12-18 17:22:01 +01:00 committed by Greg Kroah-Hartman
parent 7c72ccf09b
commit e91c021c48
1 changed files with 15 additions and 18 deletions
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33
drivers/i2c/busses/i2c-mv64xxx.c
View File

@ -1,6 +1,4 @@
/*
* drivers/i2c/busses/i2c-mv64xxx.c
*
* Driver for the i2c controller on the Marvell line of host bridges for MIPS
* and PPC (e.g, gt642[46]0, mv643[46]0, mv644[46]0).
*
@ -65,7 +63,6 @@ enum {
MV64XXX_I2C_STATE_WAITING_FOR_ADDR_2_ACK,
MV64XXX_I2C_STATE_WAITING_FOR_SLAVE_ACK,
MV64XXX_I2C_STATE_WAITING_FOR_SLAVE_DATA,
MV64XXX_I2C_STATE_ABORTING,
};
/* Driver actions */
@ -85,6 +82,7 @@ struct mv64xxx_i2c_data {
int irq;
u32 state;
u32 action;
u32 aborting;
u32 cntl_bits;
void __iomem *reg_base;
u32 reg_base_p;
@ -122,12 +120,6 @@ mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status)
return;
}
if (drv_data->state == MV64XXX_I2C_STATE_ABORTING) {
drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
drv_data->state = MV64XXX_I2C_STATE_IDLE;
return;
}
/* The status from the ctlr [mostly] tells us what to do next */
switch (status) {
/* Start condition interrupt */
@ -148,14 +140,16 @@ mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status)
/* FALLTHRU */
case MV64XXX_I2C_STATUS_MAST_WR_ADDR_2_ACK: /* 0xd0 */
case MV64XXX_I2C_STATUS_MAST_WR_ACK: /* 0x28 */
if (drv_data->bytes_left > 0) {
if ((drv_data->bytes_left == 0)
|| (drv_data->aborting
&& (drv_data->byte_posn != 0))) {
drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
drv_data->state = MV64XXX_I2C_STATE_IDLE;
} else {
drv_data->action = MV64XXX_I2C_ACTION_SEND_DATA;
drv_data->state =
MV64XXX_I2C_STATE_WAITING_FOR_SLAVE_ACK;
drv_data->bytes_left--;
} else {
drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
drv_data->state = MV64XXX_I2C_STATE_IDLE;
}
break;
@ -184,7 +178,7 @@ mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status)
}
drv_data->state = MV64XXX_I2C_STATE_WAITING_FOR_SLAVE_DATA;
if (drv_data->bytes_left == 1)
if ((drv_data->bytes_left == 1) || drv_data->aborting)
drv_data->cntl_bits &= ~MV64XXX_I2C_REG_CONTROL_ACK;
break;
@ -320,6 +314,7 @@ mv64xxx_i2c_prepare_for_io(struct mv64xxx_i2c_data *drv_data,
drv_data->msg = msg;
drv_data->byte_posn = 0;
drv_data->bytes_left = msg->len;
drv_data->aborting = 0;
drv_data->rc = 0;
drv_data->cntl_bits = MV64XXX_I2C_REG_CONTROL_ACK |
MV64XXX_I2C_REG_CONTROL_INTEN | MV64XXX_I2C_REG_CONTROL_TWSIEN;
@ -359,17 +354,19 @@ mv64xxx_i2c_wait_for_completion(struct mv64xxx_i2c_data *drv_data)
}
if (abort && drv_data->block) {
drv_data->state = MV64XXX_I2C_STATE_ABORTING;
drv_data->aborting = 1;
spin_unlock_irqrestore(&drv_data->lock, flags);
time_left = wait_event_timeout(drv_data->waitq,
!drv_data->block,
msecs_to_jiffies(drv_data->adapter.timeout));
if (time_left <= 0) {
if ((time_left <= 0) && drv_data->block) {
drv_data->state = MV64XXX_I2C_STATE_IDLE;
dev_err(&drv_data->adapter.dev,
"mv64xxx: I2C bus locked\n");
"mv64xxx: I2C bus locked, block: %d, "
"time_left: %d\n", drv_data->block,
(int)time_left);
}
} else
spin_unlock_irqrestore(&drv_data->lock, flags);
@ -510,7 +507,7 @@ mv64xxx_i2c_probe(struct platform_device *pd)
goto exit_kfree;
}
strncpy(drv_data->adapter.name, MV64XXX_I2C_CTLR_NAME " adapter",
strlcpy(drv_data->adapter.name, MV64XXX_I2C_CTLR_NAME " adapter",
I2C_NAME_SIZE);
init_waitqueue_head(&drv_data->waitq);