Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c fix from Wolfram Sang:
"A single driver bugfix for I2C.
The bug was found by systematically stress testing the driver, so I am
confident to merge it that late in the cycle although it is probably
unusually large"
* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: xlp9xx: Fix case where SSIF read transaction completes early
diff --git a/drivers/i2c/busses/i2c-xlp9xx.c b/drivers/i2c/busses/i2c-xlp9xx.c
index 1f41a4f..8a87397 100644
--- a/drivers/i2c/busses/i2c-xlp9xx.c
+++ b/drivers/i2c/busses/i2c-xlp9xx.c
@@ -191,28 +191,43 @@ static void xlp9xx_i2c_drain_rx_fifo(struct xlp9xx_i2c_dev *priv)
if (priv->len_recv) {
/* read length byte */
rlen = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_MRXFIFO);
+
+ /*
+ * We expect at least 2 interrupts for I2C_M_RECV_LEN
+ * transactions. The length is updated during the first
+ * interrupt, and the buffer contents are only copied
+ * during subsequent interrupts. If in case the interrupts
+ * get merged we would complete the transaction without
+ * copying out the bytes from RX fifo. To avoid this now we
+ * drain the fifo as and when data is available.
+ * We drained the rlen byte already, decrement total length
+ * by one.
+ */
+
+ len--;
if (rlen > I2C_SMBUS_BLOCK_MAX || rlen == 0) {
rlen = 0; /*abort transfer */
priv->msg_buf_remaining = 0;
priv->msg_len = 0;
- } else {
- *buf++ = rlen;
- if (priv->client_pec)
- ++rlen; /* account for error check byte */
- /* update remaining bytes and message length */
- priv->msg_buf_remaining = rlen;
- priv->msg_len = rlen + 1;
+ xlp9xx_i2c_update_rlen(priv);
+ return;
}
+
+ *buf++ = rlen;
+ if (priv->client_pec)
+ ++rlen; /* account for error check byte */
+ /* update remaining bytes and message length */
+ priv->msg_buf_remaining = rlen;
+ priv->msg_len = rlen + 1;
xlp9xx_i2c_update_rlen(priv);
priv->len_recv = false;
- } else {
- len = min(priv->msg_buf_remaining, len);
- for (i = 0; i < len; i++, buf++)
- *buf = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_MRXFIFO);
-
- priv->msg_buf_remaining -= len;
}
+ len = min(priv->msg_buf_remaining, len);
+ for (i = 0; i < len; i++, buf++)
+ *buf = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_MRXFIFO);
+
+ priv->msg_buf_remaining -= len;
priv->msg_buf = buf;
if (priv->msg_buf_remaining)