[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>

diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index 81031eb510565e09c707ef0d1392f5a0e34c730e..22781d84f79f256d0be11c412be15c1b6f2dc22d 100644 (file)
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -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);