[PATCH 1/2] dw_dmac: backlink to dw_dma in dw_dma_chan is superfluous

[PATCH 1/2] dw_dmac: backlink to dw_dma in dw_dma_chan is superfluous

[Andy Shevchenko]

The same information could be exctracted from the struct dma_chan.

The patch introduces two helpers dwc_get_src_data_width() and
dwc_get_dst_data_width() as well.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/dma/dw_dmac.c      |   27 ++++++++++++++++++++-------
 drivers/dma/dw_dmac_regs.h |    3 ---
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index fdae96f..a9e9a07 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -73,6 +73,22 @@ static inline unsigned int dwc_get_sms(struct dw_dma_slave *slave)
  */
 #define NR_DESCS_PER_CHANNEL	64
 
+static inline unsigned int dwc_get_src_data_width(struct dma_chan *chan)
+{
+	struct dw_dma		*dw = to_dw_dma(chan->device);
+	struct dw_dma_slave	*dws = chan->private;
+
+	return dw->data_width[dwc_get_sms(dws)];
+}
+
+static inline unsigned int dwc_get_dst_data_width(struct dma_chan *chan)
+{
+	struct dw_dma		*dw = to_dw_dma(chan->device);
+	struct dw_dma_slave	*dws = chan->private;
+
+	return dw->data_width[dwc_get_dms(dws)];
+}
+
 /*----------------------------------------------------------------------*/
 
 /*
@@ -703,7 +719,6 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
 		size_t len, unsigned long flags)
 {
 	struct dw_dma_chan	*dwc = to_dw_dma_chan(chan);
-	struct dw_dma_slave	*dws = chan->private;
 	struct dw_desc		*desc;
 	struct dw_desc		*first;
 	struct dw_desc		*prev;
@@ -726,8 +741,8 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
 
 	dwc->direction = DMA_MEM_TO_MEM;
 
-	data_width = min_t(unsigned int, dwc->dw->data_width[dwc_get_sms(dws)],
-					 dwc->dw->data_width[dwc_get_dms(dws)]);
+	data_width = min(dwc_get_src_data_width(chan),
+			 dwc_get_dst_data_width(chan));
 
 	src_width = dst_width = min_t(unsigned int, data_width,
 				      dwc_fast_fls(src | dest | len));
@@ -792,7 +807,6 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 		unsigned long flags, void *context)
 {
 	struct dw_dma_chan	*dwc = to_dw_dma_chan(chan);
-	struct dw_dma_slave	*dws = chan->private;
 	struct dma_slave_config	*sconfig = &dwc->dma_sconfig;
 	struct dw_desc		*prev;
 	struct dw_desc		*first;
@@ -826,7 +840,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 		ctllo |= sconfig->device_fc ? DWC_CTLL_FC(DW_DMA_FC_P_M2P) :
 			DWC_CTLL_FC(DW_DMA_FC_D_M2P);
 
-		data_width = dwc->dw->data_width[dwc_get_sms(dws)];
+		data_width = dwc_get_src_data_width(chan);
 
 		for_each_sg(sgl, sg, sg_len, i) {
 			struct dw_desc	*desc;
@@ -889,7 +903,7 @@ slave_sg_todev_fill_desc:
 		ctllo |= sconfig->device_fc ? DWC_CTLL_FC(DW_DMA_FC_P_P2M) :
 			DWC_CTLL_FC(DW_DMA_FC_D_P2M);
 
-		data_width = dwc->dw->data_width[dwc_get_dms(dws)];
+		data_width = dwc_get_dst_data_width(chan);
 
 		for_each_sg(sgl, sg, sg_len, i) {
 			struct dw_desc	*desc;
@@ -1720,7 +1734,6 @@ static int dw_probe(struct platform_device *pdev)
 
 		channel_clear_bit(dw, CH_EN, dwc->mask);
 
-		dwc->dw = dw;
 		dwc->direction = DMA_TRANS_NONE;
 
 		/* hardware configuration */
diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
index f9532c2..577f2dd 100644
--- a/drivers/dma/dw_dmac_regs.h
+++ b/drivers/dma/dw_dmac_regs.h
@@ -214,9 +214,6 @@ struct dw_dma_chan {
 
 	/* configuration passed via DMA_SLAVE_CONFIG */
 	struct dma_slave_config dma_sconfig;
-
-	/* backlink to dw_dma */
-	struct dw_dma		*dw;
 };
 
 static inline struct dw_dma_chan_regs __iomem *
-- 
1.7.10.4

[PATCH 2/2] dw_dmac: check for mapping errors

[Andy Shevchenko]

Otherwise we get a warning in case of CONFIG_DMA_API_DEBUG=y

[   45.775943] WARNING: at lib/dma-debug.c:933 check_unmap+0x5d6/0x6ac()
[   45.782369] dw_dmac dw_dmac.0: DMA-API: device driver failed to check map error[device address=0x00000000356efcc0] [size=28 bytes] [mapped as single]

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/dma/dw_dmac.c |   14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index a9e9a07..38eea0c 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -1107,6 +1107,7 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
 	struct dw_desc		*desc;
 	int			i;
 	unsigned long		flags;
+	int			ret = 0;
 
 	dev_vdbg(chan2dev(chan), "%s\n", __func__);
 
@@ -1131,8 +1132,7 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
 
 		desc = kzalloc(sizeof(struct dw_desc), GFP_KERNEL);
 		if (!desc) {
-			dev_info(chan2dev(chan),
-				"only allocated %d descriptors\n", i);
+			ret = -ENOMEM;
 			spin_lock_irqsave(&dwc->lock, flags);
 			break;
 		}
@@ -1143,6 +1143,13 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
 		desc->txd.flags = DMA_CTRL_ACK;
 		desc->txd.phys = dma_map_single(chan2parent(chan), &desc->lli,
 				sizeof(desc->lli), DMA_TO_DEVICE);
+		ret = dma_mapping_error(chan2parent(chan), desc->txd.phys);
+		if (ret) {
+			kfree(desc);
+			spin_lock_irqsave(&dwc->lock, flags);
+			break;
+		}
+
 		dwc_desc_put(dwc, desc);
 
 		spin_lock_irqsave(&dwc->lock, flags);
@@ -1151,6 +1158,9 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
 
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
+	if (ret)
+		dev_info(chan2dev(chan), "only allocated %d descriptors\n", i);
+
 	dev_dbg(chan2dev(chan), "%s: allocated %d descriptors\n", __func__, i);
 
 	return i;
-- 
1.7.10.4

Re: [PATCH 2/2] dw_dmac: check for mapping errors

[Viresh Kumar]

On 10 December 2012 17:06, Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
> Otherwise we get a warning in case of CONFIG_DMA_API_DEBUG=y
>
> [   45.775943] WARNING: at lib/dma-debug.c:933 check_unmap+0x5d6/0x6ac()
> [   45.782369] dw_dmac dw_dmac.0: DMA-API: device driver failed to check map error[device address=0x00000000356efcc0] [size=28 bytes] [mapped as single]
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  drivers/dma/dw_dmac.c |   14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
> index a9e9a07..38eea0c 100644
> --- a/drivers/dma/dw_dmac.c
> +++ b/drivers/dma/dw_dmac.c
> @@ -1107,6 +1107,7 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
>         struct dw_desc          *desc;
>         int                     i;
>         unsigned long           flags;
> +       int                     ret = 0;
>
>         dev_vdbg(chan2dev(chan), "%s\n", __func__);
>
> @@ -1131,8 +1132,7 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
>
>                 desc = kzalloc(sizeof(struct dw_desc), GFP_KERNEL);
>                 if (!desc) {
> -                       dev_info(chan2dev(chan),
> -                               "only allocated %d descriptors\n", i);
> +                       ret = -ENOMEM;
>                         spin_lock_irqsave(&dwc->lock, flags);
>                         break;
>                 }
> @@ -1143,6 +1143,13 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
>                 desc->txd.flags = DMA_CTRL_ACK;
>                 desc->txd.phys = dma_map_single(chan2parent(chan), &desc->lli,
>                                 sizeof(desc->lli), DMA_TO_DEVICE);
> +               ret = dma_mapping_error(chan2parent(chan), desc->txd.phys);
> +               if (ret) {
> +                       kfree(desc);
> +                       spin_lock_irqsave(&dwc->lock, flags);
> +                       break;
> +               }
> +
>                 dwc_desc_put(dwc, desc);
>
>                 spin_lock_irqsave(&dwc->lock, flags);
> @@ -1151,6 +1158,9 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
>
>         spin_unlock_irqrestore(&dwc->lock, flags);
>
> +       if (ret)
> +               dev_info(chan2dev(chan), "only allocated %d descriptors\n", i);
> +
>         dev_dbg(chan2dev(chan), "%s: allocated %d descriptors\n", __func__, i);
>
>         return i;

I would use goto with appropriate label: to avoid lock/unlock of spin_lock.

Re: [PATCH 1/2] dw_dmac: backlink to dw_dma in dw_dma_chan is superfluous

[Viresh Kumar]

On 10 December 2012 17:06, Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
> The same information could be exctracted from the struct dma_chan.
>
> The patch introduces two helpers dwc_get_src_data_width() and
> dwc_get_dst_data_width() as well.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  drivers/dma/dw_dmac.c      |   27 ++++++++++++++++++++-------
>  drivers/dma/dw_dmac_regs.h |    3 ---
>  2 files changed, 20 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
> index fdae96f..a9e9a07 100644
> --- a/drivers/dma/dw_dmac.c
> +++ b/drivers/dma/dw_dmac.c
> @@ -73,6 +73,22 @@ static inline unsigned int dwc_get_sms(struct dw_dma_slave *slave)
>   */
>  #define NR_DESCS_PER_CHANNEL   64
>
> +static inline unsigned int dwc_get_src_data_width(struct dma_chan *chan)
> +{
> +       struct dw_dma           *dw = to_dw_dma(chan->device);
> +       struct dw_dma_slave     *dws = chan->private;

I never liked the tabs used before the variable names in this driver.
Though have kept them while fixing existing routines.

So, i would like you to use spaces for new functions.

> +
> +       return dw->data_width[dwc_get_sms(dws)];
> +}
> +
> +static inline unsigned int dwc_get_dst_data_width(struct dma_chan *chan)
> +{
> +       struct dw_dma           *dw = to_dw_dma(chan->device);
> +       struct dw_dma_slave     *dws = chan->private;
> +
> +       return dw->data_width[dwc_get_dms(dws)];
> +}

Can you try merging these routines into a single routine, by adding a
single param?

>  /*----------------------------------------------------------------------*/
>
>  /*
> @@ -703,7 +719,6 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
>                 size_t len, unsigned long flags)
>  {
>         struct dw_dma_chan      *dwc = to_dw_dma_chan(chan);
> -       struct dw_dma_slave     *dws = chan->private;
>         struct dw_desc          *desc;
>         struct dw_desc          *first;
>         struct dw_desc          *prev;
> @@ -726,8 +741,8 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
>
>         dwc->direction = DMA_MEM_TO_MEM;
>
> -       data_width = min_t(unsigned int, dwc->dw->data_width[dwc_get_sms(dws)],
> -                                        dwc->dw->data_width[dwc_get_dms(dws)]);
> +       data_width = min(dwc_get_src_data_width(chan),
> +                        dwc_get_dst_data_width(chan));

min_t() is more efficient then min(), that's why it was used.

>         src_width = dst_width = min_t(unsigned int, data_width,
>                                       dwc_fast_fls(src | dest | len));
> @@ -792,7 +807,6 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
>                 unsigned long flags, void *context)
>  {
>         struct dw_dma_chan      *dwc = to_dw_dma_chan(chan);
> -       struct dw_dma_slave     *dws = chan->private;
>         struct dma_slave_config *sconfig = &dwc->dma_sconfig;
>         struct dw_desc          *prev;
>         struct dw_desc          *first;
> @@ -826,7 +840,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
>                 ctllo |= sconfig->device_fc ? DWC_CTLL_FC(DW_DMA_FC_P_M2P) :
>                         DWC_CTLL_FC(DW_DMA_FC_D_M2P);
>
> -               data_width = dwc->dw->data_width[dwc_get_sms(dws)];
> +               data_width = dwc_get_src_data_width(chan);
>
>                 for_each_sg(sgl, sg, sg_len, i) {
>                         struct dw_desc  *desc;
> @@ -889,7 +903,7 @@ slave_sg_todev_fill_desc:
>                 ctllo |= sconfig->device_fc ? DWC_CTLL_FC(DW_DMA_FC_P_P2M) :
>                         DWC_CTLL_FC(DW_DMA_FC_D_P2M);
>
> -               data_width = dwc->dw->data_width[dwc_get_dms(dws)];
> +               data_width = dwc_get_dst_data_width(chan);
>
>                 for_each_sg(sgl, sg, sg_len, i) {
>                         struct dw_desc  *desc;
> @@ -1720,7 +1734,6 @@ static int dw_probe(struct platform_device *pdev)
>
>                 channel_clear_bit(dw, CH_EN, dwc->mask);
>
> -               dwc->dw = dw;
>                 dwc->direction = DMA_TRANS_NONE;
>
>                 /* hardware configuration */
> diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
> index f9532c2..577f2dd 100644
> --- a/drivers/dma/dw_dmac_regs.h
> +++ b/drivers/dma/dw_dmac_regs.h
> @@ -214,9 +214,6 @@ struct dw_dma_chan {
>
>         /* configuration passed via DMA_SLAVE_CONFIG */
>         struct dma_slave_config dma_sconfig;
> -
> -       /* backlink to dw_dma */
> -       struct dw_dma           *dw;
>  };
>
>  static inline struct dw_dma_chan_regs __iomem *
> --
> 1.7.10.4
>