From: Mark A. Greer Date: Sun, 18 Dec 2005 16:22:01 +0000 (+0100) Subject: [PATCH] i2c: i2c-mv64xxx fix transaction abortion X-Git-Tag: v2.6.16-rc1~935^2~1^2~1 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e91c021c487110386a07facd0396e6c3b7cf9c1f;p=linux-2.6 [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 Signed-off-by: Jean Delvare --- diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c index 81031eb510..22781d84f7 100644 --- 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);