[PATCH V2 0/2] drivers: i2c: qup: Some misc fixes

[PATCH V2 0/2] drivers: i2c: qup: Some misc fixes

[Sricharan R]

One for fixing the bug with CONFIG_DEBUG_SG enabled and another
to suspend the transfer for all errors instead of just for nack.

Sricharan R (2):
  drivers: i2c: qup: Fix broken dma when CONFIG_DEBUG_SG is enabled.
  drivers: i2c: qup: Fix error handling

 drivers/i2c/busses/i2c-qup.c | 87 +++++++++++++++++++++-----------------------
 1 file changed, 42 insertions(+), 45 deletions(-)

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

[PATCH V2 1/2] drivers: i2c: qup: Fix broken dma when CONFIG_DEBUG_SG is enabled

[Sricharan R]

With CONFIG_DEBUG_SG is enabled and when dma mode is used, below dump is seen, 

------------[ cut here ]------------ 
kernel BUG at include/linux/scatterlist.h:140! 
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP 
Modules linked in: 
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.4.0-00459-g9f087b9-dirty #7 
Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT) 
task: ffffffc036868000 ti: ffffffc036870000 task.ti: ffffffc036870000 
PC is at qup_sg_set_buf.isra.13+0x138/0x154 
LR is at qup_sg_set_buf.isra.13+0x50/0x154 
pc : [<ffffffc0005a0ed8>] lr : [<ffffffc0005a0df0>] pstate: 60000145 
sp : ffffffc0368735c0 
x29: ffffffc0368735c0 x28: ffffffc036873752 
x27: ffffffc035233018 x26: ffffffc000c4e000 
x25: 0000000000000000 x24: 0000000000000004 
x23: 0000000000000000 x22: ffffffc035233668 
x21: ffffff80004e3000 x20: ffffffc0352e0018 
x19: 0000004000000000 x18: 0000000000000028 
x17: 0000000000000004 x16: ffffffc0017a39c8 
x15: 0000000000001cdf x14: ffffffc0019929d8 
x13: ffffffc0352e0018 x12: 0000000000000000 
x11: 0000000000000001 x10: 0000000000000001 
x9 : ffffffc0012b2d70 x8 : ffffff80004e3000 
x7 : 0000000000000018 x6 : 0000000030000000 
x5 : ffffffc00199f018 x4 : ffffffc035233018 
x3 : 0000000000000004 x2 : 00000000c0000000 
x1 : 0000000000000003 x0 : 0000000000000000 

Process swapper/0 (pid: 1, stack limit = 0xffffffc036870020) 
Stack: (0xffffffc0368735c0 to 0xffffffc036874000) 

Change allocation of sg buffers from dma_coherent memory to kzalloc 
to fix the issue. 

Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Reviewed-by: Andy Gross <andy.gross@linaro.org>
---
 drivers/i2c/busses/i2c-qup.c | 53 ++++++++++++++------------------------------
 1 file changed, 17 insertions(+), 36 deletions(-)

diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
index 23eaabb..8620e99 100644
--- a/drivers/i2c/busses/i2c-qup.c
+++ b/drivers/i2c/busses/i2c-qup.c
@@ -585,8 +585,8 @@ static void qup_i2c_bam_cb(void *data)
 }
 
 static int qup_sg_set_buf(struct scatterlist *sg, void *buf,
-			  struct qup_i2c_tag *tg, unsigned int buflen,
-			  struct qup_i2c_dev *qup, int map, int dir)
+			  unsigned int buflen, struct qup_i2c_dev *qup,
+			  int dir)
 {
 	int ret;
 
@@ -595,9 +595,6 @@ static int qup_sg_set_buf(struct scatterlist *sg, void *buf,
 	if (!ret)
 		return -EINVAL;
 
-	if (!map)
-		sg_dma_address(sg) = tg->addr + ((u8 *)buf - tg->start);
-
 	return 0;
 }
 
@@ -670,16 +667,15 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
 				/* scratch buf to read the start and len tags */
 				ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++],
 						     &qup->brx.tag.start[0],
-						     &qup->brx.tag,
-						     2, qup, 0, 0);
+						     2, qup, DMA_FROM_DEVICE);
 
 				if (ret)
 					return ret;
 
 				ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++],
 						     &msg->buf[limit * i],
-						     NULL, tlen, qup,
-						     1, DMA_FROM_DEVICE);
+						     tlen, qup,
+						     DMA_FROM_DEVICE);
 				if (ret)
 					return ret;
 
@@ -688,7 +684,7 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
 			}
 			ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++],
 					     &qup->start_tag.start[off],
-					     &qup->start_tag, len, qup, 0, 0);
+					     len, qup, DMA_TO_DEVICE);
 			if (ret)
 				return ret;
 
@@ -696,8 +692,7 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
 			/* scratch buf to read the BAM EOT and FLUSH tags */
 			ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++],
 					     &qup->brx.tag.start[0],
-					     &qup->brx.tag, 2,
-					     qup, 0, 0);
+					     2, qup, DMA_FROM_DEVICE);
 			if (ret)
 				return ret;
 		} else {
@@ -709,17 +704,15 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
 				len = qup_i2c_set_tags(tags, qup, msg, 1);
 
 				ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++],
-						     tags,
-						     &qup->start_tag, len,
-						     qup, 0, 0);
+						     tags, len,
+						     qup, DMA_TO_DEVICE);
 				if (ret)
 					return ret;
 
 				tx_len += len;
 				ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++],
 						     &msg->buf[limit * i],
-						     NULL, tlen, qup, 1,
-						     DMA_TO_DEVICE);
+						     tlen, qup, DMA_TO_DEVICE);
 				if (ret)
 					return ret;
 				i++;
@@ -738,8 +731,7 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
 							QUP_BAM_FLUSH_STOP;
 				ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++],
 						     &qup->btx.tag.start[0],
-						     &qup->btx.tag, len,
-						     qup, 0, 0);
+						     len, qup, DMA_TO_DEVICE);
 				if (ret)
 					return ret;
 				tx_nents += 1;
@@ -1268,6 +1260,8 @@ static int qup_i2c_xfer_v2(struct i2c_adapter *adap,
 		}
 	}
 
+	idx = 0;
+
 	do {
 		if (msgs[idx].len == 0) {
 			ret = -EINVAL;
@@ -1407,27 +1401,21 @@ static int qup_i2c_probe(struct platform_device *pdev)
 
 		/* 2 tag bytes for each block + 5 for start, stop tags */
 		size = blocks * 2 + 5;
-		qup->dpool = dma_pool_create("qup_i2c-dma-pool", &pdev->dev,
-					     size, 4, 0);
 
-		qup->start_tag.start = dma_pool_alloc(qup->dpool, GFP_KERNEL,
-						      &qup->start_tag.addr);
+		qup->start_tag.start = devm_kzalloc(&pdev->dev,
+						    size, GFP_KERNEL);
 		if (!qup->start_tag.start) {
 			ret = -ENOMEM;
 			goto fail_dma;
 		}
 
-		qup->brx.tag.start = dma_pool_alloc(qup->dpool,
-						    GFP_KERNEL,
-						    &qup->brx.tag.addr);
+		qup->brx.tag.start = devm_kzalloc(&pdev->dev, 2, GFP_KERNEL);
 		if (!qup->brx.tag.start) {
 			ret = -ENOMEM;
 			goto fail_dma;
 		}
 
-		qup->btx.tag.start = dma_pool_alloc(qup->dpool,
-						    GFP_KERNEL,
-						    &qup->btx.tag.addr);
+		qup->btx.tag.start = devm_kzalloc(&pdev->dev, 2, GFP_KERNEL);
 		if (!qup->btx.tag.start) {
 			ret = -ENOMEM;
 			goto fail_dma;
@@ -1566,13 +1554,6 @@ static int qup_i2c_remove(struct platform_device *pdev)
 	struct qup_i2c_dev *qup = platform_get_drvdata(pdev);
 
 	if (qup->is_dma) {
-		dma_pool_free(qup->dpool, qup->start_tag.start,
-			      qup->start_tag.addr);
-		dma_pool_free(qup->dpool, qup->brx.tag.start,
-			      qup->brx.tag.addr);
-		dma_pool_free(qup->dpool, qup->btx.tag.start,
-			      qup->btx.tag.addr);
-		dma_pool_destroy(qup->dpool);
 		dma_release_channel(qup->btx.dma);
 		dma_release_channel(qup->brx.dma);
 	}
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

[PATCH V2 2/2] drivers: 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 unnessecary 'timeouts' which
happens when waiting for events that would never happen when there
is already an error condition on the bus.

Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Reviewed-by: Andy Gross <andy.gross@linaro.org>
---
 drivers/i2c/busses/i2c-qup.c | 42 +++++++++++++++++++++++++++++-------------
 1 file changed, 29 insertions(+), 13 deletions(-)

diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
index 8620e99..af52a47 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 +322,31 @@ 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) {
+		if (qup->bus_err & QUP_I2C_NACK_FLAG)
+			dev_err(qup->dev, "NACK from %x\n", qup->msg->addr);
+		ret = -EIO;
+	}
+
+	return ret;
 }
 
 static void qup_i2c_set_write_mode_v2(struct qup_i2c_dev *qup,
@@ -796,7 +810,6 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
 		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");
@@ -818,6 +831,7 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
 
 			qup_i2c_rel_dma(qup);
 		}
+		ret = -EIO;
 	}
 
 	dma_unmap_sg(qup->dev, qup->btx.sg, tx_nents, DMA_TO_DEVICE);
@@ -841,9 +855,6 @@ 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);
 
@@ -882,10 +893,9 @@ static int qup_i2c_wait_for_complete(struct qup_i2c_dev *qup,
 	}
 
 	if (qup->bus_err || qup->qup_err) {
-		if (qup->bus_err & QUP_I2C_NACK_FLAG) {
+		if (qup->bus_err & QUP_I2C_NACK_FLAG)
 			dev_err(qup->dev, "NACK from %x\n", msg->addr);
-			ret = -EIO;
-		}
+		ret = -EIO;
 	}
 
 	return ret;
@@ -1178,6 +1188,9 @@ 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 +1240,9 @@ 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

Re: [V2, 1/2] drivers: i2c: qup: Fix broken dma when CONFIG_DEBUG_SG is enabled

[Naveen Kaje]

On 5/6/2016 5:31 AM, Sricharan R wrote:
> With CONFIG_DEBUG_SG is enabled and when dma mode is used, below dump is seen,
>
> ------------[ cut here ]------------
> kernel BUG at include/linux/scatterlist.h:140!
> Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
> Modules linked in:
> CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.4.0-00459-g9f087b9-dirty #7
> Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
> task: ffffffc036868000 ti: ffffffc036870000 task.ti: ffffffc036870000
> PC is at qup_sg_set_buf.isra.13+0x138/0x154
> LR is at qup_sg_set_buf.isra.13+0x50/0x154
> pc : [<ffffffc0005a0ed8>] lr : [<ffffffc0005a0df0>] pstate: 60000145
> sp : ffffffc0368735c0
> x29: ffffffc0368735c0 x28: ffffffc036873752
> x27: ffffffc035233018 x26: ffffffc000c4e000
> x25: 0000000000000000 x24: 0000000000000004
> x23: 0000000000000000 x22: ffffffc035233668
> x21: ffffff80004e3000 x20: ffffffc0352e0018
> x19: 0000004000000000 x18: 0000000000000028
> x17: 0000000000000004 x16: ffffffc0017a39c8
> x15: 0000000000001cdf x14: ffffffc0019929d8
> x13: ffffffc0352e0018 x12: 0000000000000000
> x11: 0000000000000001 x10: 0000000000000001
> x9 : ffffffc0012b2d70 x8 : ffffff80004e3000
> x7 : 0000000000000018 x6 : 0000000030000000
> x5 : ffffffc00199f018 x4 : ffffffc035233018
> x3 : 0000000000000004 x2 : 00000000c0000000
> x1 : 0000000000000003 x0 : 0000000000000000
>
> Process swapper/0 (pid: 1, stack limit = 0xffffffc036870020)
> Stack: (0xffffffc0368735c0 to 0xffffffc036874000)
>
> Change allocation of sg buffers from dma_coherent memory to kzalloc
> to fix the issue.
>
> Signed-off-by: Sricharan R <sricharan@codeaurora.org>
> Reviewed-by: Andy Gross <andy.gross@linaro.org>

Tested on QDF2432 with ACPI and SMBus support patches for regressions. 
Note that this platform does not use DMA mode.

Tested-by: Naveen Kaje <nkaje@codeaurora.org>

> ---
>   drivers/i2c/busses/i2c-qup.c | 53 ++++++++++++++------------------------------
>   1 file changed, 17 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
> index 23eaabb..8620e99 100644
> --- a/drivers/i2c/busses/i2c-qup.c
> +++ b/drivers/i2c/busses/i2c-qup.c
> @@ -585,8 +585,8 @@ static void qup_i2c_bam_cb(void *data)
>   }
>   
>   static int qup_sg_set_buf(struct scatterlist *sg, void *buf,
> -			  struct qup_i2c_tag *tg, unsigned int buflen,
> -			  struct qup_i2c_dev *qup, int map, int dir)
> +			  unsigned int buflen, struct qup_i2c_dev *qup,
> +			  int dir)
>   {
>   	int ret;
>   
> @@ -595,9 +595,6 @@ static int qup_sg_set_buf(struct scatterlist *sg, void *buf,
>   	if (!ret)
>   		return -EINVAL;
>   
> -	if (!map)
> -		sg_dma_address(sg) = tg->addr + ((u8 *)buf - tg->start);
> -
>   	return 0;
>   }
>   
> @@ -670,16 +667,15 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
>   				/* scratch buf to read the start and len tags */
>   				ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++],
>   						     &qup->brx.tag.start[0],
> -						     &qup->brx.tag,
> -						     2, qup, 0, 0);
> +						     2, qup, DMA_FROM_DEVICE);
>   
>   				if (ret)
>   					return ret;
>   
>   				ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++],
>   						     &msg->buf[limit * i],
> -						     NULL, tlen, qup,
> -						     1, DMA_FROM_DEVICE);
> +						     tlen, qup,
> +						     DMA_FROM_DEVICE);
>   				if (ret)
>   					return ret;
>   
> @@ -688,7 +684,7 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
>   			}
>   			ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++],
>   					     &qup->start_tag.start[off],
> -					     &qup->start_tag, len, qup, 0, 0);
> +					     len, qup, DMA_TO_DEVICE);
>   			if (ret)
>   				return ret;
>   
> @@ -696,8 +692,7 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
>   			/* scratch buf to read the BAM EOT and FLUSH tags */
>   			ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++],
>   					     &qup->brx.tag.start[0],
> -					     &qup->brx.tag, 2,
> -					     qup, 0, 0);
> +					     2, qup, DMA_FROM_DEVICE);
>   			if (ret)
>   				return ret;
>   		} else {
> @@ -709,17 +704,15 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
>   				len = qup_i2c_set_tags(tags, qup, msg, 1);
>   
>   				ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++],
> -						     tags,
> -						     &qup->start_tag, len,
> -						     qup, 0, 0);
> +						     tags, len,
> +						     qup, DMA_TO_DEVICE);
>   				if (ret)
>   					return ret;
>   
>   				tx_len += len;
>   				ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++],
>   						     &msg->buf[limit * i],
> -						     NULL, tlen, qup, 1,
> -						     DMA_TO_DEVICE);
> +						     tlen, qup, DMA_TO_DEVICE);
>   				if (ret)
>   					return ret;
>   				i++;
> @@ -738,8 +731,7 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
>   							QUP_BAM_FLUSH_STOP;
>   				ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++],
>   						     &qup->btx.tag.start[0],
> -						     &qup->btx.tag, len,
> -						     qup, 0, 0);
> +						     len, qup, DMA_TO_DEVICE);
>   				if (ret)
>   					return ret;
>   				tx_nents += 1;
> @@ -1268,6 +1260,8 @@ static int qup_i2c_xfer_v2(struct i2c_adapter *adap,
>   		}
>   	}
>   
> +	idx = 0;
> +
>   	do {
>   		if (msgs[idx].len == 0) {
>   			ret = -EINVAL;
> @@ -1407,27 +1401,21 @@ static int qup_i2c_probe(struct platform_device *pdev)
>   
>   		/* 2 tag bytes for each block + 5 for start, stop tags */
>   		size = blocks * 2 + 5;
> -		qup->dpool = dma_pool_create("qup_i2c-dma-pool", &pdev->dev,
> -					     size, 4, 0);
>   
> -		qup->start_tag.start = dma_pool_alloc(qup->dpool, GFP_KERNEL,
> -						      &qup->start_tag.addr);
> +		qup->start_tag.start = devm_kzalloc(&pdev->dev,
> +						    size, GFP_KERNEL);
>   		if (!qup->start_tag.start) {
>   			ret = -ENOMEM;
>   			goto fail_dma;
>   		}
>   
> -		qup->brx.tag.start = dma_pool_alloc(qup->dpool,
> -						    GFP_KERNEL,
> -						    &qup->brx.tag.addr);
> +		qup->brx.tag.start = devm_kzalloc(&pdev->dev, 2, GFP_KERNEL);
>   		if (!qup->brx.tag.start) {
>   			ret = -ENOMEM;
>   			goto fail_dma;
>   		}
>   
> -		qup->btx.tag.start = dma_pool_alloc(qup->dpool,
> -						    GFP_KERNEL,
> -						    &qup->btx.tag.addr);
> +		qup->btx.tag.start = devm_kzalloc(&pdev->dev, 2, GFP_KERNEL);
>   		if (!qup->btx.tag.start) {
>   			ret = -ENOMEM;
>   			goto fail_dma;
> @@ -1566,13 +1554,6 @@ static int qup_i2c_remove(struct platform_device *pdev)
>   	struct qup_i2c_dev *qup = platform_get_drvdata(pdev);
>   
>   	if (qup->is_dma) {
> -		dma_pool_free(qup->dpool, qup->start_tag.start,
> -			      qup->start_tag.addr);
> -		dma_pool_free(qup->dpool, qup->brx.tag.start,
> -			      qup->brx.tag.addr);
> -		dma_pool_free(qup->dpool, qup->btx.tag.start,
> -			      qup->btx.tag.addr);
> -		dma_pool_destroy(qup->dpool);
>   		dma_release_channel(qup->btx.dma);
>   		dma_release_channel(qup->brx.dma);
>   	}

Re: [V2,2/2] drivers: i2c: qup: Fix error handling

[Naveen Kaje]

On 5/6/2016 5:31 AM, Sricharan R wrote:
> 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 unnessecary 'timeouts' which
> happens when waiting for events that would never happen when there
> is already an error condition on the bus.
>
> Signed-off-by: Sricharan R <sricharan@codeaurora.org>
> Reviewed-by: Andy Gross <andy.gross@linaro.org>
Hi Sricharan,
Looks good to me. Tested on QDF2432 platform.

Reviewed-by: Naveen Kaje <nkaje@codeaurora.org>
Tested-by: Naveen Kaje <nkaje@codeaurora.org>

> ---
>   drivers/i2c/busses/i2c-qup.c | 42 +++++++++++++++++++++++++++++-------------
>   1 file changed, 29 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
> index 8620e99..af52a47 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 +322,31 @@ 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) {
> +		if (qup->bus_err & QUP_I2C_NACK_FLAG)
> +			dev_err(qup->dev, "NACK from %x\n", qup->msg->addr);
> +		ret = -EIO;
> +	}
> +
> +	return ret;
>   }
>   
>   static void qup_i2c_set_write_mode_v2(struct qup_i2c_dev *qup,
> @@ -796,7 +810,6 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
>   		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");
> @@ -818,6 +831,7 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
>   
>   			qup_i2c_rel_dma(qup);
>   		}
> +		ret = -EIO;
>   	}
>   
>   	dma_unmap_sg(qup->dev, qup->btx.sg, tx_nents, DMA_TO_DEVICE);
> @@ -841,9 +855,6 @@ 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);
>   
> @@ -882,10 +893,9 @@ static int qup_i2c_wait_for_complete(struct qup_i2c_dev *qup,
>   	}
>   
>   	if (qup->bus_err || qup->qup_err) {
> -		if (qup->bus_err & QUP_I2C_NACK_FLAG) {
> +		if (qup->bus_err & QUP_I2C_NACK_FLAG)
>   			dev_err(qup->dev, "NACK from %x\n", msg->addr);
> -			ret = -EIO;
> -		}
> +		ret = -EIO;
>   	}
>   
>   	return ret;
> @@ -1178,6 +1188,9 @@ 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 +1240,9 @@ 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;

Re: [PATCH V2 0/2] drivers: i2c: qup: Some misc fixes

[Wolfram Sang]

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On Fri, May 06, 2016 at 05:01:12PM +0530, Sricharan R wrote:
> One for fixing the bug with CONFIG_DEBUG_SG enabled and another
> to suspend the transfer for all errors instead of just for nack.

You haven't stated what was changed in V2.


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Re: [PATCH V2 1/2] drivers: i2c: qup: Fix broken dma when CONFIG_DEBUG_SG is enabled

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 1942 bytes --]

On Fri, May 06, 2016 at 05:01:13PM +0530, Sricharan R wrote:
> With CONFIG_DEBUG_SG is enabled and when dma mode is used, below dump is seen, 
> 
> ------------[ cut here ]------------ 
> kernel BUG at include/linux/scatterlist.h:140! 
> Internal error: Oops - BUG: 0 [#1] PREEMPT SMP 
> Modules linked in: 
> CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.4.0-00459-g9f087b9-dirty #7 
> Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT) 
> task: ffffffc036868000 ti: ffffffc036870000 task.ti: ffffffc036870000 
> PC is at qup_sg_set_buf.isra.13+0x138/0x154 
> LR is at qup_sg_set_buf.isra.13+0x50/0x154 
> pc : [<ffffffc0005a0ed8>] lr : [<ffffffc0005a0df0>] pstate: 60000145 
> sp : ffffffc0368735c0 
> x29: ffffffc0368735c0 x28: ffffffc036873752 
> x27: ffffffc035233018 x26: ffffffc000c4e000 
> x25: 0000000000000000 x24: 0000000000000004 
> x23: 0000000000000000 x22: ffffffc035233668 
> x21: ffffff80004e3000 x20: ffffffc0352e0018 
> x19: 0000004000000000 x18: 0000000000000028 
> x17: 0000000000000004 x16: ffffffc0017a39c8 
> x15: 0000000000001cdf x14: ffffffc0019929d8 
> x13: ffffffc0352e0018 x12: 0000000000000000 
> x11: 0000000000000001 x10: 0000000000000001 
> x9 : ffffffc0012b2d70 x8 : ffffff80004e3000 
> x7 : 0000000000000018 x6 : 0000000030000000 
> x5 : ffffffc00199f018 x4 : ffffffc035233018 
> x3 : 0000000000000004 x2 : 00000000c0000000 
> x1 : 0000000000000003 x0 : 0000000000000000 
> 
> Process swapper/0 (pid: 1, stack limit = 0xffffffc036870020) 
> Stack: (0xffffffc0368735c0 to 0xffffffc036874000) 
> 
> Change allocation of sg buffers from dma_coherent memory to kzalloc 
> to fix the issue. 

This description describes what you do. But not why it is the correct
solution to the OOPS. The OOPS  neither describes it. Please add some
more explanation.

> 
> Signed-off-by: Sricharan R <sricharan@codeaurora.org>
> Reviewed-by: Andy Gross <andy.gross@linaro.org>

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Re: [PATCH V2 2/2] drivers: i2c: qup: Fix error handling

[Wolfram Sang]

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On Fri, May 06, 2016 at 05:01:14PM +0530, Sricharan R wrote:
> 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 unnessecary 'timeouts' which
> happens when waiting for events that would never happen when there
> is already an error condition on the bus.
> 
> Signed-off-by: Sricharan R <sricharan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
> Reviewed-by: Andy Gross <andy.gross-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>

Please check Documentation/i2c/fault-codes for proper fault codes.


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Re: [PATCH V2 2/2] drivers: i2c: qup: Fix error handling

[Wolfram Sang]

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On Fri, May 13, 2016 at 01:48:23PM +0200, Wolfram Sang wrote:
> On Fri, May 06, 2016 at 05:01:14PM +0530, Sricharan R wrote:
> > 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 unnessecary 'timeouts' which
> > happens when waiting for events that would never happen when there
> > is already an error condition on the bus.
> > 
> > Signed-off-by: Sricharan R <sricharan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
> > Reviewed-by: Andy Gross <andy.gross-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> 
> Please check Documentation/i2c/fault-codes for proper fault codes.

And while we are here: NACK is not an error but a valid response. Can
you remove the dev_err related to that? Otherwise tools like i2cdetect
will probably flood your log.


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RE: [PATCH V2 0/2] drivers: i2c: qup: Some misc fixes

[Sricharan]

Hi,

> > One for fixing the bug with CONFIG_DEBUG_SG enabled and another to
> > suspend the transfer for all errors instead of just for nack.
> 
> You haven't stated what was changed in V2.
    ah, sorry, will resend..

Regards,
 Sricharan

RE: [PATCH V2 1/2] drivers: i2c: qup: Fix broken dma when CONFIG_DEBUG_SG is enabled

[Sricharan]

Hi,
> > With CONFIG_DEBUG_SG is enabled and when dma mode is used, below
> dump
> > is seen,
> >
> > ------------[ cut here ]------------
> > kernel BUG at include/linux/scatterlist.h:140!
> > Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in:
> > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.4.0-00459-g9f087b9-dirty
> > #7 Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
> > task: ffffffc036868000 ti: ffffffc036870000 task.ti: ffffffc036870000
> > PC is at qup_sg_set_buf.isra.13+0x138/0x154
> > LR is at qup_sg_set_buf.isra.13+0x50/0x154 pc : [<ffffffc0005a0ed8>]
> > lr : [<ffffffc0005a0df0>] pstate: 60000145 sp : ffffffc0368735c0
> > x29: ffffffc0368735c0 x28: ffffffc036873752
> > x27: ffffffc035233018 x26: ffffffc000c4e000
> > x25: 0000000000000000 x24: 0000000000000004
> > x23: 0000000000000000 x22: ffffffc035233668
> > x21: ffffff80004e3000 x20: ffffffc0352e0018
> > x19: 0000004000000000 x18: 0000000000000028
> > x17: 0000000000000004 x16: ffffffc0017a39c8
> > x15: 0000000000001cdf x14: ffffffc0019929d8
> > x13: ffffffc0352e0018 x12: 0000000000000000
> > x11: 0000000000000001 x10: 0000000000000001
> > x9 : ffffffc0012b2d70 x8 : ffffff80004e3000
> > x7 : 0000000000000018 x6 : 0000000030000000
> > x5 : ffffffc00199f018 x4 : ffffffc035233018
> > x3 : 0000000000000004 x2 : 00000000c0000000
> > x1 : 0000000000000003 x0 : 0000000000000000
> >
> > Process swapper/0 (pid: 1, stack limit = 0xffffffc036870020)
> > Stack: (0xffffffc0368735c0 to 0xffffffc036874000)
> >
> > Change allocation of sg buffers from dma_coherent memory to kzalloc to
> > fix the issue.
> 
> This description describes what you do. But not why it is the correct
solution
> to the OOPS. The OOPS  neither describes it. Please add some more
> explanation.
> 
   Ok,will describe it more. The reason it oops is sg_set_bug expects that
the
   buf parameter passed in should be a from the lowmem and a valid
pageframe.
  This is not true for pages from dma_alloc_coherent which can be carveouts,
hence
  the check fails. Allocating buffers using kzalloc fixes the issue.

Regards,
 Sricharan
  

RE: [PATCH V2 2/2] drivers: i2c: qup: Fix error handling

[Sricharan]

Hi,
> > > 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 unnessecary 'timeouts' which happens
> > > when waiting for events that would never happen when there is
> > > already an error condition on the bus.
> > >
> > > Signed-off-by: Sricharan R <sricharan@codeaurora.org>
> > > Reviewed-by: Andy Gross <andy.gross@linaro.org>
> >
> > Please check Documentation/i2c/fault-codes for proper fault codes.
> 
    Ok, Thanks for pointing this out. So, for NACK I think it is more
appropriate to
    return -ENXIO and -EIO for other errors. Will correct this.

> And while we are here: NACK is not an error but a valid response. Can you
> remove the dev_err related to that? Otherwise tools like i2cdetect will
> probably flood your log.
  Ok, will correct this.

Regards,
 Sricharan