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Subject[PATCH v2 08/10] i2c-i801: Handle a protocol error in byte-by-byte isr
Date
From: Corey Minyard <cminyard@mvista.com>

If a bad number of bytes is read on a transaction, have it
report an error and return -EPROTO for the transaction.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
---
drivers/i2c/busses/i2c-i801.c | 27 ++++++++++++++++-----------
1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index b415948..70da60a 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -230,7 +230,7 @@ struct i801_priv {

/* isr processing */
wait_queue_head_t waitq;
- u8 status;
+ int status;

/* Command state used by isr for byte-by-byte block transactions */
u8 subcmd;
@@ -472,16 +472,18 @@ static void i801_isr_byte_done(struct i801_priv *priv)
(priv->count == 0)) {
priv->len = inb_p(SMBHSTDAT0(priv));
if (priv->len < 1 || priv->len > I2C_SMBUS_BLOCK_MAX) {
- dev_err(&priv->pci_dev->dev,
- "Illegal SMBus block read size %d\n",
- priv->len);
- /* FIXME: Recover */
- priv->len = I2C_SMBUS_BLOCK_MAX;
- } else {
- dev_dbg(&priv->pci_dev->dev,
- "SMBus block read size is %d\n",
- priv->len);
+ /*
+ * Terminate the transaction here, to avoid
+ * getting any more interrupts that might
+ * hold us in an interrupt loop forever.
+ */
+ outb_p(inb_p(SMBHSTCNT(priv)) | SMBHSTCNT_KILL,
+ SMBHSTCNT(priv));
+ priv->status = -EPROTO;
+ return;
}
+ dev_dbg(&priv->pci_dev->dev,
+ "SMBus block read size is %d\n", priv->len);
priv->data[-1] = priv->len;
}

@@ -541,7 +543,10 @@ static irqreturn_t i801_isr(int irq, void *dev_id)
status &= SMBHSTSTS_INTR | STATUS_ERROR_FLAGS;
if (status) {
outb_p(status, SMBHSTSTS(priv));
- priv->status |= status;
+ if (status < 0)
+ priv->status = status;
+ else
+ priv->status |= status;
wake_up(&priv->waitq);
}

--
2.7.4
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