[PATCHv2 1/2] dw_dmac: backlink to dw_dma in dw_dma_chan is superfluous

[PATCHv2 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 helper function dwc_get_data_width() as well.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/dma/dw_dmac.c      |   19 ++++++++++++-------
 drivers/dma/dw_dmac_regs.h |    3 ---
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index fdae96f..427d35b 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -73,6 +73,14 @@ static inline unsigned int dwc_get_sms(struct dw_dma_slave *slave)
  */
 #define NR_DESCS_PER_CHANNEL	64
 
+static inline unsigned int dwc_get_data_width(struct dma_chan *chan, bool d)
+{
+	struct dw_dma *dw = to_dw_dma(chan->device);
+	struct dw_dma_slave *dws = chan->private;
+
+	return dw->data_width[d ? dwc_get_dms(dws) : dwc_get_sms(dws)];
+}
+
 /*----------------------------------------------------------------------*/
 
 /*
@@ -703,7 +711,6 @@ 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 +733,8 @@ 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_t(unsigned int, dwc_get_data_width(chan, true),
+			   dwc_get_data_width(chan, false));
 
 	src_width = dst_width = min_t(unsigned int, data_width,
 				      dwc_fast_fls(src | dest | len));
@@ -792,7 +799,6 @@ 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 +832,7 @@ 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_data_width(chan, false);
 
 		for_each_sg(sgl, sg, sg_len, i) {
 			struct dw_desc	*desc;
@@ -889,7 +895,7 @@ 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_data_width(chan, true);
 
 		for_each_sg(sgl, sg, sg_len, i) {
 			struct dw_desc	*desc;
@@ -1720,7 +1726,6 @@ 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

[PATCHv2 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 |   20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index 427d35b..f8937cb 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -1099,6 +1099,7 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
 	struct dw_desc		*desc;
 	int			i;
 	unsigned long		flags;
+	int			ret;
 
 	dev_vdbg(chan2dev(chan), "%s\n", __func__);
 
@@ -1122,12 +1123,8 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
 		spin_unlock_irqrestore(&dwc->lock, flags);
 
 		desc = kzalloc(sizeof(struct dw_desc), GFP_KERNEL);
-		if (!desc) {
-			dev_info(chan2dev(chan),
-				"only allocated %d descriptors\n", i);
-			spin_lock_irqsave(&dwc->lock, flags);
-			break;
-		}
+		if (!desc)
+			goto err_desc_alloc;
 
 		INIT_LIST_HEAD(&desc->tx_list);
 		dma_async_tx_descriptor_init(&desc->txd, chan);
@@ -1135,6 +1132,10 @@ 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)
+			goto err_desc_alloc;
+
 		dwc_desc_put(dwc, desc);
 
 		spin_lock_irqsave(&dwc->lock, flags);
@@ -1146,6 +1147,13 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
 	dev_dbg(chan2dev(chan), "%s: allocated %d descriptors\n", __func__, i);
 
 	return i;
+
+err_desc_alloc:
+	kfree(desc);
+
+	dev_info(chan2dev(chan), "only allocated %d descriptors\n", i);
+
+	return i;
 }
 
 static void dwc_free_chan_resources(struct dma_chan *chan)
-- 
1.7.10.4

Re: [PATCHv2 1/2] dw_dmac: backlink to dw_dma in dw_dma_chan is superfluous

[Viresh Kumar]

On 10 December 2012 20:10, Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
> The same information could be exctracted from the struct dma_chan.
> The patch introduces helper function dwc_get_data_width() as well.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  drivers/dma/dw_dmac.c      |   19 ++++++++++++-------
>  drivers/dma/dw_dmac_regs.h |    3 ---
>  2 files changed, 12 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
> index fdae96f..427d35b 100644
> --- a/drivers/dma/dw_dmac.c
> +++ b/drivers/dma/dw_dmac.c
> @@ -73,6 +73,14 @@ static inline unsigned int dwc_get_sms(struct dw_dma_slave *slave)
>   */
>  #define NR_DESCS_PER_CHANNEL   64
>
> +static inline unsigned int dwc_get_data_width(struct dma_chan *chan, bool d)
> +{
> +       struct dw_dma *dw = to_dw_dma(chan->device);
> +       struct dw_dma_slave *dws = chan->private;
> +
> +       return dw->data_width[d ? dwc_get_dms(dws) : dwc_get_sms(dws)];
> +}

I am so sorry to ask for V3 for this patch, but i didn't like the bool d at all.
Logically the variable name is not good enough in describing its purpose.

What i would have done here is:
#define SRC_MASTER 0
#define DST_MASTER 1

And used them here. :)

Rest is fine.

Re: [PATCHv2 2/2] dw_dmac: check for mapping errors

[Viresh Kumar]

On 10 December 2012 20:10, 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>

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>