[PATCH V3 2/2] i2c: qup: Fix error handling

[Sricharan R]

Among the bus errors reported from the QUP_MASTER_STATUS register
only NACK is considered and transfer gets suspended, while
other errors are ignored. Correct this and suspend the transfer
for other errors as well. This avoids unnecessary 'timeouts' which
happens when waiting for events that would never happen when there
is already an error condition on the bus. Also the error handling
procedure should be the same for both NACK and other bus errors in
case of dma mode. So correct that as well.

Signed-off-by: Sricharan R <sricharan@xxxxxxxxxxxxxx>
---
[V3] Change the return error code for NACK and other bus errors.
     Added the error handling procedure for other bus errors in
     dma mode. Removed the dev_err print in case of NACK.

 drivers/i2c/busses/i2c-qup.c | 76 ++++++++++++++++++++++++--------------------
 1 file changed, 41 insertions(+), 35 deletions(-)

diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
index 8620e99..edced86 100644
--- a/drivers/i2c/busses/i2c-qup.c
+++ b/drivers/i2c/busses/i2c-qup.c
@@ -310,6 +310,7 @@ static int qup_i2c_wait_ready(struct qup_i2c_dev *qup, int op, bool val,
 	u32 opflags;
 	u32 status;
 	u32 shift = __ffs(op);
+	int ret = 0;
 
 	len *= qup->one_byte_t;
 	/* timeout after a wait of twice the max time */
@@ -321,18 +322,28 @@ static int qup_i2c_wait_ready(struct qup_i2c_dev *qup, int op, bool val,
 
 		if (((opflags & op) >> shift) == val) {
 			if ((op == QUP_OUT_NOT_EMPTY) && qup->is_last) {
-				if (!(status & I2C_STATUS_BUS_ACTIVE))
-					return 0;
+				if (!(status & I2C_STATUS_BUS_ACTIVE)) {
+					ret = 0;
+					goto done;
+				}
 			} else {
-				return 0;
+				ret = 0;
+				goto done;
 			}
 		}
 
-		if (time_after(jiffies, timeout))
-			return -ETIMEDOUT;
-
+		if (time_after(jiffies, timeout)) {
+			ret = -ETIMEDOUT;
+			goto done;
+		}
 		usleep_range(len, len * 2);
 	}
+
+done:
+	if (qup->bus_err || qup->qup_err)
+		ret =  (qup->bus_err & QUP_I2C_NACK_FLAG) ? -ENXIO : -EIO;
+
+	return ret;
 }
 
 static void qup_i2c_set_write_mode_v2(struct qup_i2c_dev *qup,
@@ -793,39 +804,35 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
 	}
 
 	if (ret || qup->bus_err || qup->qup_err) {
-		if (qup->bus_err & QUP_I2C_NACK_FLAG) {
-			msg--;
-			dev_err(qup->dev, "NACK from %x\n", msg->addr);
-			ret = -EIO;
+		if (qup_i2c_change_state(qup, QUP_RUN_STATE)) {
+			dev_err(qup->dev, "change to run state timed out");
+			goto desc_err;
+		}
 
-			if (qup_i2c_change_state(qup, QUP_RUN_STATE)) {
-				dev_err(qup->dev, "change to run state timed out");
-				return ret;
-			}
+		if (rx_nents)
+			writel(QUP_BAM_INPUT_EOT,
+			       qup->base + QUP_OUT_FIFO_BASE);
 
-			if (rx_nents)
-				writel(QUP_BAM_INPUT_EOT,
-				       qup->base + QUP_OUT_FIFO_BASE);
+		writel(QUP_BAM_FLUSH_STOP, qup->base + QUP_OUT_FIFO_BASE);
 
-			writel(QUP_BAM_FLUSH_STOP,
-			       qup->base + QUP_OUT_FIFO_BASE);
+		qup_i2c_flush(qup);
 
-			qup_i2c_flush(qup);
+		/* wait for remaining interrupts to occur */
+		if (!wait_for_completion_timeout(&qup->xfer, HZ))
+			dev_err(qup->dev, "flush timed out\n");
 
-			/* wait for remaining interrupts to occur */
-			if (!wait_for_completion_timeout(&qup->xfer, HZ))
-				dev_err(qup->dev, "flush timed out\n");
+		qup_i2c_rel_dma(qup);
 
-			qup_i2c_rel_dma(qup);
-		}
+		ret =  (qup->bus_err & QUP_I2C_NACK_FLAG) ? -ENXIO : -EIO;
 	}
 
+desc_err:
 	dma_unmap_sg(qup->dev, qup->btx.sg, tx_nents, DMA_TO_DEVICE);
 
 	if (rx_nents)
 		dma_unmap_sg(qup->dev, qup->brx.sg, rx_nents,
 			     DMA_FROM_DEVICE);
-desc_err:
+
 	return ret;
 }
 
@@ -841,9 +848,6 @@ static int qup_i2c_bam_xfer(struct i2c_adapter *adap, struct i2c_msg *msg,
 	if (ret)
 		goto out;
 
-	qup->bus_err = 0;
-	qup->qup_err = 0;
-
 	writel(0, qup->base + QUP_MX_INPUT_CNT);
 	writel(0, qup->base + QUP_MX_OUTPUT_CNT);
 
@@ -881,12 +885,8 @@ static int qup_i2c_wait_for_complete(struct qup_i2c_dev *qup,
 		ret = -ETIMEDOUT;
 	}
 
-	if (qup->bus_err || qup->qup_err) {
-		if (qup->bus_err & QUP_I2C_NACK_FLAG) {
-			dev_err(qup->dev, "NACK from %x\n", msg->addr);
-			ret = -EIO;
-		}
-	}
+	if (qup->bus_err || qup->qup_err)
+		ret =  (qup->bus_err & QUP_I2C_NACK_FLAG) ? -ENXIO : -EIO;
 
 	return ret;
 }
@@ -1178,6 +1178,9 @@ static int qup_i2c_xfer(struct i2c_adapter *adap,
 	if (ret < 0)
 		goto out;
 
+	qup->bus_err = 0;
+	qup->qup_err = 0;
+
 	writel(1, qup->base + QUP_SW_RESET);
 	ret = qup_i2c_poll_state(qup, QUP_RESET_STATE);
 	if (ret)
@@ -1227,6 +1230,9 @@ static int qup_i2c_xfer_v2(struct i2c_adapter *adap,
 	struct qup_i2c_dev *qup = i2c_get_adapdata(adap);
 	int ret, len, idx = 0, use_dma = 0;
 
+	qup->bus_err = 0;
+	qup->qup_err = 0;
+
 	ret = pm_runtime_get_sync(qup->dev);
 	if (ret < 0)
 		goto out;
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation