[PATCH 0/8] Various dmaengine cleanups

[PATCH 0/8] Various dmaengine cleanups

[Peter Griffin]

Hi Vinod,

This series is a bunch of cleanup updates to various
dmaengine drivers, based on some of the review feeback to my fdma series.

regards,

Peter.

Peter Griffin (8):
  dmaengine: fsl-edma: Fix clock handling error paths
  dmaengine: fsl-edma: print error code in error messages.
  dmaengine: coh901318: Only calculate residue if txstate exists.
  dmaengine: s3c24xx: Simplify code in s3c24xx_dma_tx_status()
  dmaengine: ste_dma40: Only calculate residue if txstate exists.
  dmaengine: sun6i-dma: Only calculate residue if state exists.
  dmaengine: tegra20-apb-dma: Only calculate residue if txstate exists.
  dmaengine: Remove site specific OOM error messages on kzalloc

 drivers/dma/amba-pl08x.c        | 10 +---------
 drivers/dma/bestcomm/bestcomm.c |  2 --
 drivers/dma/coh901318.c         |  2 +-
 drivers/dma/edma.c              | 16 ++++------------
 drivers/dma/fsl-edma.c          | 25 +++++++++++++++++++------
 drivers/dma/fsldma.c            |  2 --
 drivers/dma/k3dma.c             | 10 ++++------
 drivers/dma/mmp_tdma.c          |  5 ++---
 drivers/dma/moxart-dma.c        |  4 +---
 drivers/dma/nbpfaxi.c           |  5 ++---
 drivers/dma/pl330.c             |  5 +----
 drivers/dma/ppc4xx/adma.c       |  2 --
 drivers/dma/s3c24xx-dma.c       | 11 ++---------
 drivers/dma/sh/shdmac.c         |  9 ++-------
 drivers/dma/sh/sudmac.c         |  9 ++-------
 drivers/dma/sirf-dma.c          |  5 ++---
 drivers/dma/ste_dma40.c         |  6 ++----
 drivers/dma/sun6i-dma.c         |  2 +-
 drivers/dma/tegra20-apb-dma.c   | 13 ++++---------
 drivers/dma/timb_dma.c          |  8 ++------
 20 files changed, 52 insertions(+), 99 deletions(-)

-- 
1.9.1

[PATCH 1/8] dmaengine: fsl-edma: Fix clock handling error paths

[Peter Griffin]

Currently fsl-edma doesn't clk_disable_unprepare()
its clocks on error conditions. This patch adds a
fsl_disable_clocks helper for this, and also only
disables clocks which were enabled if encountering
an error whilst enabling clocks.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
---
 drivers/dma/fsl-edma.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/fsl-edma.c b/drivers/dma/fsl-edma.c
index be2e62b..7208fc9 100644
--- a/drivers/dma/fsl-edma.c
+++ b/drivers/dma/fsl-edma.c
@@ -852,6 +852,14 @@ fsl_edma_irq_init(struct platform_device *pdev, struct fsl_edma_engine *fsl_edma
 	return 0;
 }
 
+static void fsl_disable_clocks(struct fsl_edma_engine *fsl_edma)
+{
+	int i;
+
+	for (i = 0; i < DMAMUX_NR; i++)
+		clk_disable_unprepare(fsl_edma->muxclk[i]);
+}
+
 static int fsl_edma_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
@@ -897,6 +905,10 @@ static int fsl_edma_probe(struct platform_device *pdev)
 
 		ret = clk_prepare_enable(fsl_edma->muxclk[i]);
 		if (ret) {
+			/* disable only clks which were enabled on error */
+			for (; i >= 0; i--)
+				clk_disable_unprepare(fsl_edma->muxclk[i]);
+
 			dev_err(&pdev->dev, "DMAMUX clk block failed.\n");
 			return ret;
 		}
@@ -952,6 +964,7 @@ static int fsl_edma_probe(struct platform_device *pdev)
 	ret = dma_async_device_register(&fsl_edma->dma_dev);
 	if (ret) {
 		dev_err(&pdev->dev, "Can't register Freescale eDMA engine.\n");
+		fsl_disable_clocks(fsl_edma);
 		return ret;
 	}
 
@@ -959,6 +972,7 @@ static int fsl_edma_probe(struct platform_device *pdev)
 	if (ret) {
 		dev_err(&pdev->dev, "Can't register Freescale eDMA of_dma.\n");
 		dma_async_device_unregister(&fsl_edma->dma_dev);
+		fsl_disable_clocks(fsl_edma);
 		return ret;
 	}
 
@@ -972,13 +986,10 @@ static int fsl_edma_remove(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
 	struct fsl_edma_engine *fsl_edma = platform_get_drvdata(pdev);
-	int i;
 
 	of_dma_controller_free(np);
 	dma_async_device_unregister(&fsl_edma->dma_dev);
-
-	for (i = 0; i < DMAMUX_NR; i++)
-		clk_disable_unprepare(fsl_edma->muxclk[i]);
+	fsl_disable_clocks(fsl_edma);
 
 	return 0;
 }
-- 
1.9.1

[PATCH 2/8] dmaengine: fsl-edma: print error code in error messages.

[Peter Griffin]

It is useful to print the error code as part of the error
message.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
---
 drivers/dma/fsl-edma.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/fsl-edma.c b/drivers/dma/fsl-edma.c
index 7208fc9..cc06eea 100644
--- a/drivers/dma/fsl-edma.c
+++ b/drivers/dma/fsl-edma.c
@@ -963,14 +963,16 @@ static int fsl_edma_probe(struct platform_device *pdev)
 
 	ret = dma_async_device_register(&fsl_edma->dma_dev);
 	if (ret) {
-		dev_err(&pdev->dev, "Can't register Freescale eDMA engine.\n");
+		dev_err(&pdev->dev,
+			"Can't register Freescale eDMA engine. (%d)\n", ret);
 		fsl_disable_clocks(fsl_edma);
 		return ret;
 	}
 
 	ret = of_dma_controller_register(np, fsl_edma_xlate, fsl_edma);
 	if (ret) {
-		dev_err(&pdev->dev, "Can't register Freescale eDMA of_dma.\n");
+		dev_err(&pdev->dev,
+			"Can't register Freescale eDMA of_dma. (%d)\n", ret);
 		dma_async_device_unregister(&fsl_edma->dma_dev);
 		fsl_disable_clocks(fsl_edma);
 		return ret;
-- 
1.9.1

[PATCH 3/8] dmaengine: coh901318: Only calculate residue if txstate exists.

[Peter Griffin]

There is no point in calculating the residue if there is no
txstate to store the value.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
---
 drivers/dma/coh901318.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/coh901318.c b/drivers/dma/coh901318.c
index c340ca9..c100616 100644
--- a/drivers/dma/coh901318.c
+++ b/drivers/dma/coh901318.c
@@ -2422,7 +2422,7 @@ coh901318_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
 	enum dma_status ret;
 
 	ret = dma_cookie_status(chan, cookie, txstate);
-	if (ret == DMA_COMPLETE)
+	if (ret == DMA_COMPLETE || !txstate)
 		return ret;
 
 	dma_set_residue(txstate, coh901318_get_bytes_left(chan));
-- 
1.9.1

[PATCH 4/8] dmaengine: s3c24xx: Simplify code in s3c24xx_dma_tx_status()

[Peter Griffin]

Doing so saves a few lines of code in the driver.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
---
 drivers/dma/s3c24xx-dma.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/dma/s3c24xx-dma.c b/drivers/dma/s3c24xx-dma.c
index 17ccdfd..f7d2c7a 100644
--- a/drivers/dma/s3c24xx-dma.c
+++ b/drivers/dma/s3c24xx-dma.c
@@ -768,16 +768,12 @@ static enum dma_status s3c24xx_dma_tx_status(struct dma_chan *chan,
 
 	spin_lock_irqsave(&s3cchan->vc.lock, flags);
 	ret = dma_cookie_status(chan, cookie, txstate);
-	if (ret == DMA_COMPLETE) {
-		spin_unlock_irqrestore(&s3cchan->vc.lock, flags);
-		return ret;
-	}
 
 	/*
 	 * There's no point calculating the residue if there's
 	 * no txstate to store the value.
 	 */
-	if (!txstate) {
+	if (ret == DMA_COMPLETE || !txstate) {
 		spin_unlock_irqrestore(&s3cchan->vc.lock, flags);
 		return ret;
 	}
-- 
1.9.1

[PATCH 5/8] dmaengine: ste_dma40: Only calculate residue if txstate exists.

[Peter Griffin]

There is no point calculating the residue if there is
no txstate to store the value.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
---
 drivers/dma/ste_dma40.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index 6fb8307..378cc47 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -2588,7 +2588,7 @@ static enum dma_status d40_tx_status(struct dma_chan *chan,
 	}
 
 	ret = dma_cookie_status(chan, cookie, txstate);
-	if (ret != DMA_COMPLETE)
+	if (ret != DMA_COMPLETE && txstate)
 		dma_set_residue(txstate, stedma40_residue(chan));
 
 	if (d40_is_paused(d40c))
-- 
1.9.1

[PATCH 6/8] dmaengine: sun6i-dma: Only calculate residue if state exists.

[Peter Griffin]

There is no point in calculating the residue if state does not
exist to store the value.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
---
 drivers/dma/sun6i-dma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
index 5065ca4..3835fcd 100644
--- a/drivers/dma/sun6i-dma.c
+++ b/drivers/dma/sun6i-dma.c
@@ -865,7 +865,7 @@ static enum dma_status sun6i_dma_tx_status(struct dma_chan *chan,
 	size_t bytes = 0;
 
 	ret = dma_cookie_status(chan, cookie, state);
-	if (ret == DMA_COMPLETE)
+	if (ret == DMA_COMPLETE || !state)
 		return ret;
 
 	spin_lock_irqsave(&vchan->vc.lock, flags);
-- 
1.9.1

[PATCH 7/8] dmaengine: tegra20-apb-dma: Only calculate residue if txstate exists.

[Peter Griffin]

There is no point calculating the residue if there is
no txstate to store the value.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
---
 drivers/dma/tegra20-apb-dma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 01e316f..7f4af8c 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -814,7 +814,7 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
 	unsigned int residual;
 
 	ret = dma_cookie_status(dc, cookie, txstate);
-	if (ret == DMA_COMPLETE)
+	if (ret == DMA_COMPLETE || !txstate)
 		return ret;
 
 	spin_lock_irqsave(&tdc->lock, flags);
-- 
1.9.1

[PATCH 8/8] dmaengine: Remove site specific OOM error messages on kzalloc

[Peter Griffin]

If kzalloc() fails it will issue it's own error message including
a dump_stack(). So remove the site specific error messages.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
---
 drivers/dma/amba-pl08x.c        | 10 +---------
 drivers/dma/bestcomm/bestcomm.c |  2 --
 drivers/dma/edma.c              | 16 ++++------------
 drivers/dma/fsldma.c            |  2 --
 drivers/dma/k3dma.c             | 10 ++++------
 drivers/dma/mmp_tdma.c          |  5 ++---
 drivers/dma/moxart-dma.c        |  4 +---
 drivers/dma/nbpfaxi.c           |  5 ++---
 drivers/dma/pl330.c             |  5 +----
 drivers/dma/ppc4xx/adma.c       |  2 --
 drivers/dma/s3c24xx-dma.c       |  5 +----
 drivers/dma/sh/shdmac.c         |  9 ++-------
 drivers/dma/sh/sudmac.c         |  9 ++-------
 drivers/dma/sirf-dma.c          |  5 ++---
 drivers/dma/ste_dma40.c         |  4 +---
 drivers/dma/tegra20-apb-dma.c   | 11 +++--------
 drivers/dma/timb_dma.c          |  8 ++------
 17 files changed, 28 insertions(+), 84 deletions(-)

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index 81db1c4..939a7c3 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -1443,8 +1443,6 @@ static struct dma_async_tx_descriptor *pl08x_prep_dma_memcpy(
 	dsg = kzalloc(sizeof(struct pl08x_sg), GFP_NOWAIT);
 	if (!dsg) {
 		pl08x_free_txd(pl08x, txd);
-		dev_err(&pl08x->adev->dev, "%s no memory for pl080 sg\n",
-				__func__);
 		return NULL;
 	}
 	list_add_tail(&dsg->node, &txd->dsg_list);
@@ -1901,11 +1899,8 @@ static int pl08x_dma_init_virtual_channels(struct pl08x_driver_data *pl08x,
 	 */
 	for (i = 0; i < channels; i++) {
 		chan = kzalloc(sizeof(*chan), GFP_KERNEL);
-		if (!chan) {
-			dev_err(&pl08x->adev->dev,
-				"%s no memory for channel\n", __func__);
+		if (!chan)
 			return -ENOMEM;
-		}
 
 		chan->host = pl08x;
 		chan->state = PL08X_CHAN_IDLE;
@@ -2360,9 +2355,6 @@ static int pl08x_probe(struct amba_device *adev, const struct amba_id *id)
 	pl08x->phy_chans = kzalloc((vd->channels * sizeof(*pl08x->phy_chans)),
 			GFP_KERNEL);
 	if (!pl08x->phy_chans) {
-		dev_err(&adev->dev, "%s failed to allocate "
-			"physical channel holders\n",
-			__func__);
 		ret = -ENOMEM;
 		goto out_no_phychans;
 	}
diff --git a/drivers/dma/bestcomm/bestcomm.c b/drivers/dma/bestcomm/bestcomm.c
index 180fedb..7ce8437 100644
--- a/drivers/dma/bestcomm/bestcomm.c
+++ b/drivers/dma/bestcomm/bestcomm.c
@@ -397,8 +397,6 @@ static int mpc52xx_bcom_probe(struct platform_device *op)
 	/* Get a clean struct */
 	bcom_eng = kzalloc(sizeof(struct bcom_engine), GFP_KERNEL);
 	if (!bcom_eng) {
-		printk(KERN_ERR DRIVER_NAME ": "
-			"Can't allocate state structure\n");
 		rv = -ENOMEM;
 		goto error_sramclean;
 	}
diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index 8181ed1..3c84cd8 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -1069,10 +1069,8 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg(
 
 	edesc = kzalloc(sizeof(*edesc) + sg_len * sizeof(edesc->pset[0]),
 			GFP_ATOMIC);
-	if (!edesc) {
-		dev_err(dev, "%s: Failed to allocate a descriptor\n", __func__);
+	if (!edesc)
 		return NULL;
-	}
 
 	edesc->pset_nr = sg_len;
 	edesc->residue = 0;
@@ -1173,10 +1171,8 @@ static struct dma_async_tx_descriptor *edma_prep_dma_memcpy(
 
 	edesc = kzalloc(sizeof(*edesc) + nslots * sizeof(edesc->pset[0]),
 			GFP_ATOMIC);
-	if (!edesc) {
-		dev_dbg(dev, "Failed to allocate a descriptor\n");
+	if (!edesc)
 		return NULL;
-	}
 
 	edesc->pset_nr = nslots;
 	edesc->residue = edesc->residue_stat = len;
@@ -1298,10 +1294,8 @@ static struct dma_async_tx_descriptor *edma_prep_dma_cyclic(
 
 	edesc = kzalloc(sizeof(*edesc) + nslots * sizeof(edesc->pset[0]),
 			GFP_ATOMIC);
-	if (!edesc) {
-		dev_err(dev, "%s: Failed to allocate a descriptor\n", __func__);
+	if (!edesc)
 		return NULL;
-	}
 
 	edesc->cyclic = 1;
 	edesc->pset_nr = nslots;
@@ -2207,10 +2201,8 @@ static int edma_probe(struct platform_device *pdev)
 		return ret;
 
 	ecc = devm_kzalloc(dev, sizeof(*ecc), GFP_KERNEL);
-	if (!ecc) {
-		dev_err(dev, "Can't allocate controller\n");
+	if (!ecc)
 		return -ENOMEM;
-	}
 
 	ecc->dev = dev;
 	ecc->id = pdev->id;
diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index a8828ed..911b717 100644
--- a/drivers/dma/fsldma.c
+++ b/drivers/dma/fsldma.c
@@ -1234,7 +1234,6 @@ static int fsl_dma_chan_probe(struct fsldma_device *fdev,
 	/* alloc channel */
 	chan = kzalloc(sizeof(*chan), GFP_KERNEL);
 	if (!chan) {
-		dev_err(fdev->dev, "no free memory for DMA channels!\n");
 		err = -ENOMEM;
 		goto out_return;
 	}
@@ -1340,7 +1339,6 @@ static int fsldma_of_probe(struct platform_device *op)
 
 	fdev = kzalloc(sizeof(*fdev), GFP_KERNEL);
 	if (!fdev) {
-		dev_err(&op->dev, "No enough memory for 'priv'\n");
 		err = -ENOMEM;
 		goto out_return;
 	}
diff --git a/drivers/dma/k3dma.c b/drivers/dma/k3dma.c
index 1ba2fd7..35961af 100644
--- a/drivers/dma/k3dma.c
+++ b/drivers/dma/k3dma.c
@@ -425,10 +425,9 @@ static struct dma_async_tx_descriptor *k3_dma_prep_memcpy(
 
 	num = DIV_ROUND_UP(len, DMA_MAX_SIZE);
 	ds = kzalloc(sizeof(*ds) + num * sizeof(ds->desc_hw[0]), GFP_ATOMIC);
-	if (!ds) {
-		dev_dbg(chan->device->dev, "vchan %p: kzalloc fail\n", &c->vc);
+	if (!ds)
 		return NULL;
-	}
+
 	ds->desc_hw_lli = __virt_to_phys((unsigned long)&ds->desc_hw[0]);
 	ds->size = len;
 	ds->desc_num = num;
@@ -481,10 +480,9 @@ static struct dma_async_tx_descriptor *k3_dma_prep_slave_sg(
 	}
 
 	ds = kzalloc(sizeof(*ds) + num * sizeof(ds->desc_hw[0]), GFP_ATOMIC);
-	if (!ds) {
-		dev_dbg(chan->device->dev, "vchan %p: kzalloc fail\n", &c->vc);
+	if (!ds)
 		return NULL;
-	}
+
 	ds->desc_hw_lli = __virt_to_phys((unsigned long)&ds->desc_hw[0]);
 	ds->desc_num = num;
 	num = 0;
diff --git a/drivers/dma/mmp_tdma.c b/drivers/dma/mmp_tdma.c
index 3df0422..ba7f412 100644
--- a/drivers/dma/mmp_tdma.c
+++ b/drivers/dma/mmp_tdma.c
@@ -551,10 +551,9 @@ static int mmp_tdma_chan_init(struct mmp_tdma_device *tdev,
 
 	/* alloc channel */
 	tdmac = devm_kzalloc(tdev->dev, sizeof(*tdmac), GFP_KERNEL);
-	if (!tdmac) {
-		dev_err(tdev->dev, "no free memory for DMA channels!\n");
+	if (!tdmac)
 		return -ENOMEM;
-	}
+
 	if (irq)
 		tdmac->irq = irq;
 	tdmac->dev	   = tdev->dev;
diff --git a/drivers/dma/moxart-dma.c b/drivers/dma/moxart-dma.c
index 631c443..b3a1d9a 100644
--- a/drivers/dma/moxart-dma.c
+++ b/drivers/dma/moxart-dma.c
@@ -574,10 +574,8 @@ static int moxart_probe(struct platform_device *pdev)
 	struct moxart_dmadev *mdc;
 
 	mdc = devm_kzalloc(dev, sizeof(*mdc), GFP_KERNEL);
-	if (!mdc) {
-		dev_err(dev, "can't allocate DMA container\n");
+	if (!mdc)
 		return -ENOMEM;
-	}
 
 	irq = irq_of_parse_and_map(node, 0);
 	if (irq == NO_IRQ) {
diff --git a/drivers/dma/nbpfaxi.c b/drivers/dma/nbpfaxi.c
index 2b5a198..9f0e98b 100644
--- a/drivers/dma/nbpfaxi.c
+++ b/drivers/dma/nbpfaxi.c
@@ -1300,10 +1300,9 @@ static int nbpf_probe(struct platform_device *pdev)
 
 	nbpf = devm_kzalloc(dev, sizeof(*nbpf) + num_channels *
 			    sizeof(nbpf->chan[0]), GFP_KERNEL);
-	if (!nbpf) {
-		dev_err(dev, "Memory allocation failed\n");
+	if (!nbpf)
 		return -ENOMEM;
-	}
+
 	dma_dev = &nbpf->dma_dev;
 	dma_dev->dev = dev;
 
diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 372b435..c8767d3 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -2828,10 +2828,8 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
 
 	/* Allocate a new DMAC and its Channels */
 	pl330 = devm_kzalloc(&adev->dev, sizeof(*pl330), GFP_KERNEL);
-	if (!pl330) {
-		dev_err(&adev->dev, "unable to allocate mem\n");
+	if (!pl330)
 		return -ENOMEM;
-	}
 
 	pd = &pl330->ddma;
 	pd->dev = &adev->dev;
@@ -2890,7 +2888,6 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
 	pl330->peripherals = kzalloc(num_chan * sizeof(*pch), GFP_KERNEL);
 	if (!pl330->peripherals) {
 		ret = -ENOMEM;
-		dev_err(&adev->dev, "unable to allocate pl330->peripherals\n");
 		goto probe_err2;
 	}
 
diff --git a/drivers/dma/ppc4xx/adma.c b/drivers/dma/ppc4xx/adma.c
index 9217f89..da3688b 100644
--- a/drivers/dma/ppc4xx/adma.c
+++ b/drivers/dma/ppc4xx/adma.c
@@ -4084,7 +4084,6 @@ static int ppc440spe_adma_probe(struct platform_device *ofdev)
 	/* create a device */
 	adev = kzalloc(sizeof(*adev), GFP_KERNEL);
 	if (!adev) {
-		dev_err(&ofdev->dev, "failed to allocate device\n");
 		initcode = PPC_ADMA_INIT_ALLOC;
 		ret = -ENOMEM;
 		goto err_adev_alloc;
@@ -4145,7 +4144,6 @@ static int ppc440spe_adma_probe(struct platform_device *ofdev)
 	/* create a channel */
 	chan = kzalloc(sizeof(*chan), GFP_KERNEL);
 	if (!chan) {
-		dev_err(&ofdev->dev, "can't allocate channel structure\n");
 		initcode = PPC_ADMA_INIT_CHANNEL;
 		ret = -ENOMEM;
 		goto err_chan_alloc;
diff --git a/drivers/dma/s3c24xx-dma.c b/drivers/dma/s3c24xx-dma.c
index f7d2c7a..0d2d187 100644
--- a/drivers/dma/s3c24xx-dma.c
+++ b/drivers/dma/s3c24xx-dma.c
@@ -1101,11 +1101,8 @@ static int s3c24xx_dma_init_virtual_channels(struct s3c24xx_dma_engine *s3cdma,
 	 */
 	for (i = 0; i < channels; i++) {
 		chan = devm_kzalloc(dmadev->dev, sizeof(*chan), GFP_KERNEL);
-		if (!chan) {
-			dev_err(dmadev->dev,
-				"%s no memory for channel\n", __func__);
+		if (!chan)
 			return -ENOMEM;
-		}
 
 		chan->id = i;
 		chan->host = s3cdma;
diff --git a/drivers/dma/sh/shdmac.c b/drivers/dma/sh/shdmac.c
index 80d8640..c94ffab 100644
--- a/drivers/dma/sh/shdmac.c
+++ b/drivers/dma/sh/shdmac.c
@@ -532,11 +532,8 @@ static int sh_dmae_chan_probe(struct sh_dmae_device *shdev, int id,
 
 	sh_chan = devm_kzalloc(sdev->dma_dev.dev, sizeof(struct sh_dmae_chan),
 			       GFP_KERNEL);
-	if (!sh_chan) {
-		dev_err(sdev->dma_dev.dev,
-			"No free memory for allocating dma channels!\n");
+	if (!sh_chan)
 		return -ENOMEM;
-	}
 
 	schan = &sh_chan->shdma_chan;
 	schan->max_xfer_len = SH_DMA_TCR_MAX + 1;
@@ -732,10 +729,8 @@ static int sh_dmae_probe(struct platform_device *pdev)
 
 	shdev = devm_kzalloc(&pdev->dev, sizeof(struct sh_dmae_device),
 			     GFP_KERNEL);
-	if (!shdev) {
-		dev_err(&pdev->dev, "Not enough memory\n");
+	if (!shdev)
 		return -ENOMEM;
-	}
 
 	dma_dev = &shdev->shdma_dev.dma_dev;
 
diff --git a/drivers/dma/sh/sudmac.c b/drivers/dma/sh/sudmac.c
index 6da2eaa..69b9564 100644
--- a/drivers/dma/sh/sudmac.c
+++ b/drivers/dma/sh/sudmac.c
@@ -245,11 +245,8 @@ static int sudmac_chan_probe(struct sudmac_device *su_dev, int id, int irq,
 	int err;
 
 	sc = devm_kzalloc(&pdev->dev, sizeof(struct sudmac_chan), GFP_KERNEL);
-	if (!sc) {
-		dev_err(sdev->dma_dev.dev,
-			"No free memory for allocating dma channels!\n");
+	if (!sc)
 		return -ENOMEM;
-	}
 
 	schan = &sc->shdma_chan;
 	schan->max_xfer_len = 64 * 1024 * 1024 - 1;
@@ -349,10 +346,8 @@ static int sudmac_probe(struct platform_device *pdev)
 	err = -ENOMEM;
 	su_dev = devm_kzalloc(&pdev->dev, sizeof(struct sudmac_device),
 			      GFP_KERNEL);
-	if (!su_dev) {
-		dev_err(&pdev->dev, "Not enough memory\n");
+	if (!su_dev)
 		return err;
-	}
 
 	dma_dev = &su_dev->shdma_dev.dma_dev;
 
diff --git a/drivers/dma/sirf-dma.c b/drivers/dma/sirf-dma.c
index e48350e..8ea51c7 100644
--- a/drivers/dma/sirf-dma.c
+++ b/drivers/dma/sirf-dma.c
@@ -854,10 +854,9 @@ static int sirfsoc_dma_probe(struct platform_device *op)
 	int ret, i;
 
 	sdma = devm_kzalloc(dev, sizeof(*sdma), GFP_KERNEL);
-	if (!sdma) {
-		dev_err(dev, "Memory exhausted!\n");
+	if (!sdma)
 		return -ENOMEM;
-	}
+
 	data = (struct sirfsoc_dmadata *)
 		(of_match_device(op->dev.driver->of_match_table,
 				 &op->dev)->data);
diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index 378cc47..8b18e44 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -3237,10 +3237,8 @@ static struct d40_base * __init d40_hw_detect_init(struct platform_device *pdev)
 		       (num_phy_chans + num_log_chans + num_memcpy_chans) *
 		       sizeof(struct d40_chan), GFP_KERNEL);
 
-	if (base == NULL) {
-		d40_err(&pdev->dev, "Out of memory\n");
+	if (base == NULL)
 		goto failure;
-	}
 
 	base->rev = rev;
 	base->clk = clk;
diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 7f4af8c..032884f 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -300,10 +300,8 @@ static struct tegra_dma_desc *tegra_dma_desc_get(
 
 	/* Allocate DMA desc */
 	dma_desc = kzalloc(sizeof(*dma_desc), GFP_NOWAIT);
-	if (!dma_desc) {
-		dev_err(tdc2dev(tdc), "dma_desc alloc failed\n");
+	if (!dma_desc)
 		return NULL;
-	}
 
 	dma_async_tx_descriptor_init(&dma_desc->txd, &tdc->dma_chan);
 	dma_desc->txd.tx_submit = tegra_dma_tx_submit;
@@ -340,8 +338,7 @@ static struct tegra_dma_sg_req *tegra_dma_sg_req_get(
 	spin_unlock_irqrestore(&tdc->lock, flags);
 
 	sg_req = kzalloc(sizeof(struct tegra_dma_sg_req), GFP_NOWAIT);
-	if (!sg_req)
-		dev_err(tdc2dev(tdc), "sg_req alloc failed\n");
+
 	return sg_req;
 }
 
@@ -1319,10 +1316,8 @@ static int tegra_dma_probe(struct platform_device *pdev)
 
 	tdma = devm_kzalloc(&pdev->dev, sizeof(*tdma) + cdata->nr_channels *
 			sizeof(struct tegra_dma_channel), GFP_KERNEL);
-	if (!tdma) {
-		dev_err(&pdev->dev, "Error: memory allocation failed\n");
+	if (!tdma)
 		return -ENOMEM;
-	}
 
 	tdma->dev = &pdev->dev;
 	tdma->chip_data = cdata;
diff --git a/drivers/dma/timb_dma.c b/drivers/dma/timb_dma.c
index 559cd40..e82745a 100644
--- a/drivers/dma/timb_dma.c
+++ b/drivers/dma/timb_dma.c
@@ -337,18 +337,14 @@ static struct timb_dma_desc *td_alloc_init_desc(struct timb_dma_chan *td_chan)
 	int err;
 
 	td_desc = kzalloc(sizeof(struct timb_dma_desc), GFP_KERNEL);
-	if (!td_desc) {
-		dev_err(chan2dev(chan), "Failed to alloc descriptor\n");
+	if (!td_desc)
 		goto out;
-	}
 
 	td_desc->desc_list_len = td_chan->desc_elems * TIMB_DMA_DESC_SIZE;
 
 	td_desc->desc_list = kzalloc(td_desc->desc_list_len, GFP_KERNEL);
-	if (!td_desc->desc_list) {
-		dev_err(chan2dev(chan), "Failed to alloc descriptor\n");
+	if (!td_desc->desc_list)
 		goto err;
-	}
 
 	dma_async_tx_descriptor_init(&td_desc->txd, chan);
 	td_desc->txd.tx_submit = td_tx_submit;
-- 
1.9.1

Re: [PATCH 8/8] dmaengine: Remove site specific OOM error messages on kzalloc

[Jon Hunter]

On 07/06/16 18:38, Peter Griffin wrote:
> If kzalloc() fails it will issue it's own error message including
> a dump_stack(). So remove the site specific error messages.
> 
> Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
> ---
>  drivers/dma/amba-pl08x.c        | 10 +---------
>  drivers/dma/bestcomm/bestcomm.c |  2 --
>  drivers/dma/edma.c              | 16 ++++------------
>  drivers/dma/fsldma.c            |  2 --
>  drivers/dma/k3dma.c             | 10 ++++------
>  drivers/dma/mmp_tdma.c          |  5 ++---
>  drivers/dma/moxart-dma.c        |  4 +---
>  drivers/dma/nbpfaxi.c           |  5 ++---
>  drivers/dma/pl330.c             |  5 +----
>  drivers/dma/ppc4xx/adma.c       |  2 --
>  drivers/dma/s3c24xx-dma.c       |  5 +----
>  drivers/dma/sh/shdmac.c         |  9 ++-------
>  drivers/dma/sh/sudmac.c         |  9 ++-------
>  drivers/dma/sirf-dma.c          |  5 ++---
>  drivers/dma/ste_dma40.c         |  4 +---
>  drivers/dma/tegra20-apb-dma.c   | 11 +++--------
>  drivers/dma/timb_dma.c          |  8 ++------
>  17 files changed, 28 insertions(+), 84 deletions(-)

[snip]

> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> index 7f4af8c..032884f 100644
> --- a/drivers/dma/tegra20-apb-dma.c
> +++ b/drivers/dma/tegra20-apb-dma.c
> @@ -300,10 +300,8 @@ static struct tegra_dma_desc *tegra_dma_desc_get(
>  
>  	/* Allocate DMA desc */
>  	dma_desc = kzalloc(sizeof(*dma_desc), GFP_NOWAIT);
> -	if (!dma_desc) {
> -		dev_err(tdc2dev(tdc), "dma_desc alloc failed\n");
> +	if (!dma_desc)
>  		return NULL;
> -	}
>  
>  	dma_async_tx_descriptor_init(&dma_desc->txd, &tdc->dma_chan);
>  	dma_desc->txd.tx_submit = tegra_dma_tx_submit;
> @@ -340,8 +338,7 @@ static struct tegra_dma_sg_req *tegra_dma_sg_req_get(
>  	spin_unlock_irqrestore(&tdc->lock, flags);
>  
>  	sg_req = kzalloc(sizeof(struct tegra_dma_sg_req), GFP_NOWAIT);
> -	if (!sg_req)
> -		dev_err(tdc2dev(tdc), "sg_req alloc failed\n");
> +
>  	return sg_req;
>  }
>  
> @@ -1319,10 +1316,8 @@ static int tegra_dma_probe(struct platform_device *pdev)
>  
>  	tdma = devm_kzalloc(&pdev->dev, sizeof(*tdma) + cdata->nr_channels *
>  			sizeof(struct tegra_dma_channel), GFP_KERNEL);
> -	if (!tdma) {
> -		dev_err(&pdev->dev, "Error: memory allocation failed\n");
> +	if (!tdma)
>  		return -ENOMEM;
> -	}
>  
>  	tdma->dev = &pdev->dev;
>  	tdma->chip_data = cdata;

For the tegra portion ...

Acked-by: Jon Hunter <jonathanh@nvidia.com>

Cheers
Jon

-- 
nvpublic

Re: [PATCH 7/8] dmaengine: tegra20-apb-dma: Only calculate residue if txstate exists.

[Jon Hunter]

Hi Peter,

On 07/06/16 18:38, Peter Griffin wrote:
> There is no point calculating the residue if there is
> no txstate to store the value.
> 
> Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
> ---
>  drivers/dma/tegra20-apb-dma.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> index 01e316f..7f4af8c 100644
> --- a/drivers/dma/tegra20-apb-dma.c
> +++ b/drivers/dma/tegra20-apb-dma.c
> @@ -814,7 +814,7 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
>  	unsigned int residual;
>  
>  	ret = dma_cookie_status(dc, cookie, txstate);
> -	if (ret == DMA_COMPLETE)
> +	if (ret == DMA_COMPLETE || !txstate)
>  		return ret;

Thanks for reporting this. I agree that we should not do this, however, 
looking at the code for Tegra, I am wondering if this could change the
actual state that is returned. Looking at dma_cookie_status() it will
call dma_async_is_complete() which will return either DMA_COMPLETE or
DMA_IN_PROGRESS. It could be possible that the actual state for the
DMA transfer in the tegra driver is DMA_ERROR, so I am wondering if we
should do something like the following  ...

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 01e316f73559..45edab7418d0 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -822,13 +822,8 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
        /* Check on wait_ack desc status */
        list_for_each_entry(dma_desc, &tdc->free_dma_desc, node) {
                if (dma_desc->txd.cookie == cookie) {
-                       residual =  dma_desc->bytes_requested -
-                                       (dma_desc->bytes_transferred %
-                                               dma_desc->bytes_requested);
-                       dma_set_residue(txstate, residual);
                        ret = dma_desc->dma_status;
-                       spin_unlock_irqrestore(&tdc->lock, flags);
-                       return ret;
+                       goto found;
                }
        }
 
@@ -836,17 +831,23 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
        list_for_each_entry(sg_req, &tdc->pending_sg_req, node) {
                dma_desc = sg_req->dma_desc;
                if (dma_desc->txd.cookie == cookie) {
-                       residual =  dma_desc->bytes_requested -
-                                       (dma_desc->bytes_transferred %
-                                               dma_desc->bytes_requested);
-                       dma_set_residue(txstate, residual);
                        ret = dma_desc->dma_status;
-                       spin_unlock_irqrestore(&tdc->lock, flags);
-                       return ret;
+                       goto found;
                }
        }
 
-       dev_dbg(tdc2dev(tdc), "cookie %d does not found\n", cookie);
+       dev_warn(tdc2dev(tdc), "cookie %d not found\n", cookie);
+       spin_unlock_irqrestore(&tdc->lock, flags);
+       return ret;
+
+found:
+       if (txstate) {
+               residual = dma_desc->bytes_requested -
+                          (dma_desc->bytes_transferred %
+                           dma_desc->bytes_requested);
+               dma_set_residue(txstate, residual);
+       }
+
        spin_unlock_irqrestore(&tdc->lock, flags);
        return ret;
 }

Cheers
Jon

-- 
nvpublic

Re: [PATCH 8/8] dmaengine: Remove site specific OOM error messages on kzalloc

[Linus Walleij]

On Tue, Jun 7, 2016 at 7:38 PM, Peter Griffin <peter.griffin@linaro.org> wrote:

> If kzalloc() fails it will issue it's own error message including
> a dump_stack(). So remove the site specific error messages.
>
> Signed-off-by: Peter Griffin <peter.griffin@linaro.org>

Acked-by: Linus Walleij <linus.walleij@linaro.org>

A few subsystems may use a cleanup like this...
I wonder how many unnecessary prints I've introduced
myself :P

Yours,
Linus Walleij

Re: [PATCH 3/8] dmaengine: coh901318: Only calculate residue if txstate exists.

[Linus Walleij]

On Tue, Jun 7, 2016 at 7:38 PM, Peter Griffin <peter.griffin@linaro.org> wrote:

> There is no point in calculating the residue if there is no
> txstate to store the value.
>
> Signed-off-by: Peter Griffin <peter.griffin@linaro.org>

Acked-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij

Re: [PATCH 5/8] dmaengine: ste_dma40: Only calculate residue if txstate exists.

[Linus Walleij]

On Tue, Jun 7, 2016 at 7:38 PM, Peter Griffin <peter.griffin@linaro.org> wrote:

> There is no point calculating the residue if there is
> no txstate to store the value.
>
> Signed-off-by: Peter Griffin <peter.griffin@linaro.org>

Acked-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij

Re: [PATCH 8/8] dmaengine: Remove site specific OOM error messages on kzalloc

[Lee Jones]

On Wed, 08 Jun 2016, Linus Walleij wrote:

> On Tue, Jun 7, 2016 at 7:38 PM, Peter Griffin <peter.griffin@linaro.org> wrote:
> 
> > If kzalloc() fails it will issue it's own error message including
> > a dump_stack(). So remove the site specific error messages.
> >
> > Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
> 
> Acked-by: Linus Walleij <linus.walleij@linaro.org>
> 
> A few subsystems may use a cleanup like this...
> I wonder how many unnecessary prints I've introduced
> myself :P

Wolfram did some analysis on this a while back.  IIRC he also
presented on his findings at ELC(?).
 
-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH 8/8] dmaengine: Remove site specific OOM error messages on kzalloc

[Vinod Koul]

On Wed, Jun 08, 2016 at 02:12:27PM +0200, Linus Walleij wrote:
> On Tue, Jun 7, 2016 at 7:38 PM, Peter Griffin <peter.griffin@linaro.org> wrote:
> 
> > If kzalloc() fails it will issue it's own error message including
> > a dump_stack(). So remove the site specific error messages.
> >
> > Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
> 
> Acked-by: Linus Walleij <linus.walleij@linaro.org>
> 
> A few subsystems may use a cleanup like this...
> I wonder how many unnecessary prints I've introduced
> myself :P

Yes that should be case with mine too :)

I think adding a coccinelle script and doing this treewise might be great

Thanks
-- 
~Vinod

Re: [PATCH 7/8] dmaengine: tegra20-apb-dma: Only calculate residue if txstate exists.

[Vinod Koul]

On Wed, Jun 08, 2016 at 09:51:57AM +0100, Jon Hunter wrote:
> Hi Peter,
> 
> On 07/06/16 18:38, Peter Griffin wrote:
> > There is no point calculating the residue if there is
> > no txstate to store the value.
> > 
> > Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
> > ---
> >  drivers/dma/tegra20-apb-dma.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> > index 01e316f..7f4af8c 100644
> > --- a/drivers/dma/tegra20-apb-dma.c
> > +++ b/drivers/dma/tegra20-apb-dma.c
> > @@ -814,7 +814,7 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
> >  	unsigned int residual;
> >  
> >  	ret = dma_cookie_status(dc, cookie, txstate);
> > -	if (ret == DMA_COMPLETE)
> > +	if (ret == DMA_COMPLETE || !txstate)
> >  		return ret;
> 
> Thanks for reporting this. I agree that we should not do this, however, 
> looking at the code for Tegra, I am wondering if this could change the
> actual state that is returned. Looking at dma_cookie_status() it will
> call dma_async_is_complete() which will return either DMA_COMPLETE or
> DMA_IN_PROGRESS. It could be possible that the actual state for the
> DMA transfer in the tegra driver is DMA_ERROR, so I am wondering if we
> should do something like the following  ...

This one is stopping code execution when residue is not valid. Do notice
that it check for DMA_COMPLETE OR txstate. In other cases, wit will return
'that' state when txstate is NULL.

I am going to apply this.

> 
> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> index 01e316f73559..45edab7418d0 100644
> --- a/drivers/dma/tegra20-apb-dma.c
> +++ b/drivers/dma/tegra20-apb-dma.c
> @@ -822,13 +822,8 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
>         /* Check on wait_ack desc status */
>         list_for_each_entry(dma_desc, &tdc->free_dma_desc, node) {
>                 if (dma_desc->txd.cookie == cookie) {
> -                       residual =  dma_desc->bytes_requested -
> -                                       (dma_desc->bytes_transferred %
> -                                               dma_desc->bytes_requested);
> -                       dma_set_residue(txstate, residual);
>                         ret = dma_desc->dma_status;
> -                       spin_unlock_irqrestore(&tdc->lock, flags);
> -                       return ret;
> +                       goto found;
>                 }
>         }
>  
> @@ -836,17 +831,23 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
>         list_for_each_entry(sg_req, &tdc->pending_sg_req, node) {
>                 dma_desc = sg_req->dma_desc;
>                 if (dma_desc->txd.cookie == cookie) {
> -                       residual =  dma_desc->bytes_requested -
> -                                       (dma_desc->bytes_transferred %
> -                                               dma_desc->bytes_requested);
> -                       dma_set_residue(txstate, residual);
>                         ret = dma_desc->dma_status;
> -                       spin_unlock_irqrestore(&tdc->lock, flags);
> -                       return ret;
> +                       goto found;
>                 }
>         }
>  
> -       dev_dbg(tdc2dev(tdc), "cookie %d does not found\n", cookie);
> +       dev_warn(tdc2dev(tdc), "cookie %d not found\n", cookie);
> +       spin_unlock_irqrestore(&tdc->lock, flags);
> +       return ret;
> +
> +found:
> +       if (txstate) {
> +               residual = dma_desc->bytes_requested -
> +                          (dma_desc->bytes_transferred %
> +                           dma_desc->bytes_requested);
> +               dma_set_residue(txstate, residual);
> +       }
> +

I feel this optimizes stuff, which seems okay. Feel free to send as proper
patch.

>         spin_unlock_irqrestore(&tdc->lock, flags);
>         return ret;
>  }
> 
> Cheers
> Jon
> 
> -- 
> nvpublic

-- 
~Vinod

Re: [PATCH 0/8] Various dmaengine cleanups

[Vinod Koul]

On Tue, Jun 07, 2016 at 06:38:33PM +0100, Peter Griffin wrote:
> Hi Vinod,
> 
> This series is a bunch of cleanup updates to various
> dmaengine drivers, based on some of the review feeback to my fdma series.

Good cleanup, Applied, thanks

-- 
~Vinod

Re: [PATCH 7/8] dmaengine: tegra20-apb-dma: Only calculate residue if txstate exists.

[Jon Hunter]

On 21/06/16 17:01, Vinod Koul wrote:
> On Wed, Jun 08, 2016 at 09:51:57AM +0100, Jon Hunter wrote:
>> Hi Peter,
>>
>> On 07/06/16 18:38, Peter Griffin wrote:
>>> There is no point calculating the residue if there is
>>> no txstate to store the value.
>>>
>>> Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
>>> ---
>>>  drivers/dma/tegra20-apb-dma.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
>>> index 01e316f..7f4af8c 100644
>>> --- a/drivers/dma/tegra20-apb-dma.c
>>> +++ b/drivers/dma/tegra20-apb-dma.c
>>> @@ -814,7 +814,7 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
>>>  	unsigned int residual;
>>>  
>>>  	ret = dma_cookie_status(dc, cookie, txstate);
>>> -	if (ret == DMA_COMPLETE)
>>> +	if (ret == DMA_COMPLETE || !txstate)
>>>  		return ret;
>>
>> Thanks for reporting this. I agree that we should not do this, however, 
>> looking at the code for Tegra, I am wondering if this could change the
>> actual state that is returned. Looking at dma_cookie_status() it will
>> call dma_async_is_complete() which will return either DMA_COMPLETE or
>> DMA_IN_PROGRESS. It could be possible that the actual state for the
>> DMA transfer in the tegra driver is DMA_ERROR, so I am wondering if we
>> should do something like the following  ...
> 
> This one is stopping code execution when residue is not valid. Do notice
> that it check for DMA_COMPLETE OR txstate. In other cases, wit will return
> 'that' state when txstate is NULL.

Sorry what do you mean by "this one"?

My point is that if the status is not DMA_COMPLETE, then it is possible
that it could be DMA_ERROR (for tegra that is). However,
dma_cookie_status will only return DMA_IN_PROGRESS or DMA_COMPLETE and
so if 'txstate' is NULL we will not see the DMA_ERROR status anymore and
just think it is in progress when it is actually an error.

I do agree that the driver is broken as we are not checking for
!txstate, but this also changes the behaviour a bit.

Cheers
Jon

-- 
nvpublic

Re: [PATCH 7/8] dmaengine: tegra20-apb-dma: Only calculate residue if txstate exists.

[Vinod Koul]

On Tue, Jun 21, 2016 at 06:19:50PM +0100, Jon Hunter wrote:
> 
> On 21/06/16 17:01, Vinod Koul wrote:
> > On Wed, Jun 08, 2016 at 09:51:57AM +0100, Jon Hunter wrote:
> >> Hi Peter,
> >>
> >> On 07/06/16 18:38, Peter Griffin wrote:
> >>> There is no point calculating the residue if there is
> >>> no txstate to store the value.
> >>>
> >>> Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
> >>> ---
> >>>  drivers/dma/tegra20-apb-dma.c | 2 +-
> >>>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> >>> index 01e316f..7f4af8c 100644
> >>> --- a/drivers/dma/tegra20-apb-dma.c
> >>> +++ b/drivers/dma/tegra20-apb-dma.c
> >>> @@ -814,7 +814,7 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
> >>>  	unsigned int residual;
> >>>  
> >>>  	ret = dma_cookie_status(dc, cookie, txstate);
> >>> -	if (ret == DMA_COMPLETE)
> >>> +	if (ret == DMA_COMPLETE || !txstate)
> >>>  		return ret;
> >>
> >> Thanks for reporting this. I agree that we should not do this, however, 
> >> looking at the code for Tegra, I am wondering if this could change the
> >> actual state that is returned. Looking at dma_cookie_status() it will
> >> call dma_async_is_complete() which will return either DMA_COMPLETE or
> >> DMA_IN_PROGRESS. It could be possible that the actual state for the
> >> DMA transfer in the tegra driver is DMA_ERROR, so I am wondering if we
> >> should do something like the following  ...
> > 
> > This one is stopping code execution when residue is not valid. Do notice
> > that it check for DMA_COMPLETE OR txstate. In other cases, wit will return
> > 'that' state when txstate is NULL.
> 
> Sorry what do you mean by "this one"?

the patch

> 
> My point is that if the status is not DMA_COMPLETE, then it is possible
> that it could be DMA_ERROR (for tegra that is). 

right it can be any state... and we check for only DMA_COMPLETE as residue
has no meaning.

> However,
> dma_cookie_status will only return DMA_IN_PROGRESS or DMA_COMPLETE and
> so if 'txstate' is NULL we will not see the DMA_ERROR status anymore and
> just think it is in progress when it is actually an error.

Yes that is an existing issue, if you are reporting DMA_ERROR then you
should add a check for DMA_ERROR as well and not do residue calculation for
that case.

> 
> I do agree that the driver is broken as we are not checking for
> !txstate, but this also changes the behaviour a bit.

It changes for better and not worse. Btw pls feel free to send a patch
handling DMA_ERROR :)

-- 
~Vinod