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

[PATCH 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 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>
---
 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 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>
---
 drivers/i2c/busses/i2c-qup.c | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
index 8620e99..8afb733 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,
@@ -882,10 +896,9 @@ 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;
@@ -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: [PATCH 0/2] drivers: i2c: qup: Some misc fixes

[Naveen Kaje]

From: Naveen Kaje <nkaje@codeaurora.org>

Hi Sricharan,
I tested these changes. They did not cause any regressions on QDF2432. Note that QDF2432 does not use DMA mode.
I based my patches (http://marc.info/?l=linux-i2c&m=146231797008963&w=2 and http://marc.info/?l=linux-i2c&m=146231798708969&w=2) on top of these fixes.
There are no merge conflicts.

Thanks,
Naveen

---

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

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

[Andy Gross]

On Mon, May 02, 2016 at 10:53:57AM +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@codeaurora.org>
> ---
>  drivers/i2c/busses/i2c-qup.c | 34 +++++++++++++++++++++++++---------
>  1 file changed, 25 insertions(+), 9 deletions(-)

Reviewed-by: Andy Gross <andy.gross@linaro.org>

<snip>

> @@ -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;
> +

What about the initial setting of these?  Does this need to be removed from the
main xfer function?

>  	ret = pm_runtime_get_sync(qup->dev);
>  	if (ret < 0)
>  		goto out;

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

[Andy Gross]

On Mon, May 02, 2016 at 10:53:56AM +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.
> 
> Signed-off-by: Sricharan R <sricharan@codeaurora.org>

Looks fine.

Reviewed-by: Andy Gross <andy.gross@linaro.org>

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

[Sricharan]

Hi Andy,

> -----Original Message-----
> From: Andy Gross [mailto:andy.gross@linaro.org]
> Sent: Thursday, May 05, 2016 10:52 PM
> To: Sricharan R <sricharan@codeaurora.org>
> Cc: devicetree@vger.kernel.org; architt@codeaurora.org; linux-arm-
> msm@vger.kernel.org; ntelkar@codeaurora.org; galak@codeaurora.org;
> linux-kernel@vger.kernel.org; linux-i2c@vger.kernel.org; iivanov@mm-
> sol.com; agross@codeaurora.org; dmaengine@vger.kernel.org; linux-arm-
> kernel@lists.infradead.org
> Subject: Re: [PATCH 2/2] drivers: i2c: qup: Fix error handling
> 
> On Mon, May 02, 2016 at 10:53:57AM +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@codeaurora.org>
> > ---
> >  drivers/i2c/busses/i2c-qup.c | 34 +++++++++++++++++++++++++---------
> >  1 file changed, 25 insertions(+), 9 deletions(-)
> 
> Reviewed-by: Andy Gross <andy.gross@linaro.org>
> 
 Thanks.
> <snip>
> 
> > @@ -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;
> > +
> 
> What about the initial setting of these?  Does this need to be removed
from
> the main xfer function?
  Thanks for the catch. Will remove in bam_xfer , redundant.
  Now that there are i2x_xfer_v2 and i2c_xfer, 
   its not set in the old i2c_xfer call, where as it should be set there
   as well. I will change this and resend.

Regards,
 Sricharan