[PATCH 1/2] dw_dmac: store direction in the custom channel structure

[PATCH 1/2] dw_dmac: store direction in the custom channel structure

[Andy Shevchenko]

Currently the direction value is come from the generic slave configuration
structure and explicitly as a preparation function parameter. The first one is
kinda obsoleted. Thus, we have to store the value passed to the preparation
function somewhere in our structures to be able to use it later. The best
candidate to provide the storage is a custom channel structure. Until now we
still keep and check the direction field of the slave config structure as well.

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

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index 5e2c4dc..58c6d3c 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -178,9 +178,9 @@ static void dwc_initialize(struct dw_dma_chan *dwc)
 		cfghi = dws->cfg_hi;
 		cfglo |= dws->cfg_lo & ~DWC_CFGL_CH_PRIOR_MASK;
 	} else {
-		if (dwc->dma_sconfig.direction == DMA_MEM_TO_DEV)
+		if (dwc->direction == DMA_MEM_TO_DEV)
 			cfghi = DWC_CFGH_DST_PER(dwc->dma_sconfig.slave_id);
-		else if (dwc->dma_sconfig.direction == DMA_DEV_TO_MEM)
+		else if (dwc->direction == DMA_DEV_TO_MEM)
 			cfghi = DWC_CFGH_SRC_PER(dwc->dma_sconfig.slave_id);
 	}
 
@@ -807,6 +807,8 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 	if (unlikely(!dws || !sg_len))
 		return NULL;
 
+	dwc->direction = direction;
+
 	prev = first = NULL;
 
 	switch (direction) {
@@ -983,6 +985,7 @@ set_runtime_config(struct dma_chan *chan, struct dma_slave_config *sconfig)
 		return -EINVAL;
 
 	memcpy(&dwc->dma_sconfig, sconfig, sizeof(*sconfig));
+	dwc->direction = sconfig->direction;
 
 	convert_burst(&dwc->dma_sconfig.src_maxburst);
 	convert_burst(&dwc->dma_sconfig.dst_maxburst);
@@ -1339,6 +1342,8 @@ struct dw_cyclic_desc *dw_dma_cyclic_prep(struct dma_chan *chan,
 	if (unlikely(!is_slave_xfer(direction)))
 		goto out_err;
 
+	dwc->direction = direction;
+
 	if (direction == DMA_MEM_TO_DEV)
 		reg_width = __ffs(sconfig->dst_addr_width);
 	else
@@ -1713,6 +1718,7 @@ static int __devinit dw_probe(struct platform_device *pdev)
 		channel_clear_bit(dw, CH_EN, dwc->mask);
 
 		dwc->dw = dw;
+		dwc->direction = DMA_TRANS_NONE;
 
 		/* hardware configuration */
 		if (autocfg) {
diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
index 8881e9b..362aba1 100644
--- a/drivers/dma/dw_dmac_regs.h
+++ b/drivers/dma/dw_dmac_regs.h
@@ -9,6 +9,7 @@
  * published by the Free Software Foundation.
  */
 
+#include <linux/dmaengine.h>
 #include <linux/dw_dmac.h>
 
 #define DW_DMA_MAX_NR_CHANNELS	8
@@ -188,6 +189,7 @@ struct dw_dma_chan {
 	void __iomem		*ch_regs;
 	u8			mask;
 	u8			priority;
+	enum dma_transfer_direction direction;
 	bool			paused;
 	bool			initialized;
 
-- 
1.7.10.4

[PATCH 2/2] dw_dmac: make usage of dw_dma_slave optional

[Andy Shevchenko]

The driver requires a custom slave configuration to be present to be able to
make the slave transfers. Nevertheless, in some cases we need only the request
line as an additional information to the generic slave configuration.  The
request line is provided by slave_id parameter of the dma_slave_config
structure. That's why the custom slave configuration could be optional for such
cases.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/dma/dw_dmac.c |   13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index 58c6d3c..8d50374 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -50,11 +50,12 @@ static inline unsigned int dwc_get_sms(struct dw_dma_slave *slave)
 		struct dw_dma_slave *__slave = (_chan->private);	\
 		struct dw_dma_chan *_dwc = to_dw_dma_chan(_chan);	\
 		struct dma_slave_config	*_sconfig = &_dwc->dma_sconfig;	\
+		bool _is_slave = is_slave_xfer(_dwc->direction);	\
 		int _dms = dwc_get_dms(__slave);		\
 		int _sms = dwc_get_sms(__slave);		\
-		u8 _smsize = __slave ? _sconfig->src_maxburst :	\
+		u8 _smsize = _is_slave ? _sconfig->src_maxburst :	\
 			DW_DMA_MSIZE_16;			\
-		u8 _dmsize = __slave ? _sconfig->dst_maxburst :	\
+		u8 _dmsize = _is_slave ? _sconfig->dst_maxburst :	\
 			DW_DMA_MSIZE_16;			\
 								\
 		(DWC_CTLL_DST_MSIZE(_dmsize)			\
@@ -325,7 +326,7 @@ dwc_descriptor_complete(struct dw_dma_chan *dwc, struct dw_desc *desc,
 	list_splice_init(&desc->tx_list, &dwc->free_list);
 	list_move(&desc->desc_node, &dwc->free_list);
 
-	if (!dwc->chan.private) {
+	if (!is_slave_xfer(dwc->direction)) {
 		struct device *parent = chan2parent(&dwc->chan);
 		if (!(txd->flags & DMA_COMPL_SKIP_DEST_UNMAP)) {
 			if (txd->flags & DMA_COMPL_DEST_UNMAP_SINGLE)
@@ -804,7 +805,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 
 	dev_vdbg(chan2dev(chan), "%s\n", __func__);
 
-	if (unlikely(!dws || !sg_len))
+	if (unlikely(!is_slave_xfer(direction) || !sg_len))
 		return NULL;
 
 	dwc->direction = direction;
@@ -980,8 +981,8 @@ set_runtime_config(struct dma_chan *chan, struct dma_slave_config *sconfig)
 {
 	struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
 
-	/* Check if it is chan is configured for slave transfers */
-	if (!chan->private)
+	/* Check if chan will be configured for slave transfers */
+	if (!is_slave_xfer(sconfig->direction))
 		return -EINVAL;
 
 	memcpy(&dwc->dma_sconfig, sconfig, sizeof(*sconfig));
-- 
1.7.10.4

Re: [PATCH 1/2] dw_dmac: store direction in the custom channel structure

[Viresh Kumar]

On 20 November 2012 19:08, Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
> Currently the direction value is come from the generic slave configuration

s/is come/comes

> structure and explicitly as a preparation function parameter. The first one is
> kinda obsoleted. Thus, we have to store the value passed to the preparation
> function somewhere in our structures to be able to use it later. The best
> candidate to provide the storage is a custom channel structure. Until now we
> still keep and check the direction field of the slave config structure as well.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  drivers/dma/dw_dmac.c      |   10 ++++++++--
>  drivers/dma/dw_dmac_regs.h |    2 ++
>  2 files changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
> index 5e2c4dc..58c6d3c 100644
> --- a/drivers/dma/dw_dmac.c
> +++ b/drivers/dma/dw_dmac.c
> @@ -178,9 +178,9 @@ static void dwc_initialize(struct dw_dma_chan *dwc)
>                 cfghi = dws->cfg_hi;
>                 cfglo |= dws->cfg_lo & ~DWC_CFGL_CH_PRIOR_MASK;
>         } else {
> -               if (dwc->dma_sconfig.direction == DMA_MEM_TO_DEV)
> +               if (dwc->direction == DMA_MEM_TO_DEV)
>                         cfghi = DWC_CFGH_DST_PER(dwc->dma_sconfig.slave_id);
> -               else if (dwc->dma_sconfig.direction == DMA_DEV_TO_MEM)
> +               else if (dwc->direction == DMA_DEV_TO_MEM)
>                         cfghi = DWC_CFGH_SRC_PER(dwc->dma_sconfig.slave_id);
>         }

I have a doubt here. This routine is called both for memcpy and slave transfers.
Earlier if (dws), code was used to check slave/non-slave transfer but with your
earlier patch, for if (!dws) case too, there can be slave transfers
based on direction.

Consider a situation. A channel is used for slave transfers and have
direction set
to DMA_DEV_TO_MEM. Now, channel is freed and used for memcpy. Now the
direction value is retained as we haven't updated it. So, is this a
potential bug?

> @@ -807,6 +807,8 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
>         if (unlikely(!dws || !sg_len))
>                 return NULL;
>
> +       dwc->direction = direction;
> +
>         prev = first = NULL;
>
>         switch (direction) {
> @@ -983,6 +985,7 @@ set_runtime_config(struct dma_chan *chan, struct dma_slave_config *sconfig)
>                 return -EINVAL;
>
>         memcpy(&dwc->dma_sconfig, sconfig, sizeof(*sconfig));
> +       dwc->direction = sconfig->direction;
>
>         convert_burst(&dwc->dma_sconfig.src_maxburst);
>         convert_burst(&dwc->dma_sconfig.dst_maxburst);
> @@ -1339,6 +1342,8 @@ struct dw_cyclic_desc *dw_dma_cyclic_prep(struct dma_chan *chan,
>         if (unlikely(!is_slave_xfer(direction)))
>                 goto out_err;
>
> +       dwc->direction = direction;
> +
>         if (direction == DMA_MEM_TO_DEV)
>                 reg_width = __ffs(sconfig->dst_addr_width);
>         else
> @@ -1713,6 +1718,7 @@ static int __devinit dw_probe(struct platform_device *pdev)
>                 channel_clear_bit(dw, CH_EN, dwc->mask);
>
>                 dwc->dw = dw;
> +               dwc->direction = DMA_TRANS_NONE;
>
>                 /* hardware configuration */
>                 if (autocfg) {
> diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
> index 8881e9b..362aba1 100644
> --- a/drivers/dma/dw_dmac_regs.h
> +++ b/drivers/dma/dw_dmac_regs.h
> @@ -9,6 +9,7 @@
>   * published by the Free Software Foundation.
>   */
>
> +#include <linux/dmaengine.h>
>  #include <linux/dw_dmac.h>
>
>  #define DW_DMA_MAX_NR_CHANNELS 8
> @@ -188,6 +189,7 @@ struct dw_dma_chan {
>         void __iomem            *ch_regs;
>         u8                      mask;
>         u8                      priority;
> +       enum dma_transfer_direction direction;
>         bool                    paused;
>         bool                    initialized;

better align it with tabs and update earlier ones too with extra tabs.

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

Re: [PATCH 2/2] dw_dmac: make usage of dw_dma_slave optional

[Viresh Kumar]

On 20 November 2012 19:08, Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
> The driver requires a custom slave configuration to be present to be able to
> make the slave transfers. Nevertheless, in some cases we need only the request
> line as an additional information to the generic slave configuration.  The
> request line is provided by slave_id parameter of the dma_slave_config
> structure. That's why the custom slave configuration could be optional for such
> cases.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

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

Re: [PATCH 1/2] dw_dmac: store direction in the custom channel structure

[Andy Shevchenko]

On Tue, 2012-11-20 at 19:38 +0530, Viresh Kumar wrote: 
> On 20 November 2012 19:08, Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> > Currently the direction value is come from the generic slave configuration
> 
> s/is come/comes
> 
> > structure and explicitly as a preparation function parameter. The first one is
> > kinda obsoleted. Thus, we have to store the value passed to the preparation
> > function somewhere in our structures to be able to use it later. The best
> > candidate to provide the storage is a custom channel structure. Until now we
> > still keep and check the direction field of the slave config structure as well.
> >
> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > ---
> >  drivers/dma/dw_dmac.c      |   10 ++++++++--
> >  drivers/dma/dw_dmac_regs.h |    2 ++
> >  2 files changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
> > index 5e2c4dc..58c6d3c 100644
> > --- a/drivers/dma/dw_dmac.c
> > +++ b/drivers/dma/dw_dmac.c
> > @@ -178,9 +178,9 @@ static void dwc_initialize(struct dw_dma_chan *dwc)
> >                 cfghi = dws->cfg_hi;
> >                 cfglo |= dws->cfg_lo & ~DWC_CFGL_CH_PRIOR_MASK;
> >         } else {
> > -               if (dwc->dma_sconfig.direction == DMA_MEM_TO_DEV)
> > +               if (dwc->direction == DMA_MEM_TO_DEV)
> >                         cfghi = DWC_CFGH_DST_PER(dwc->dma_sconfig.slave_id);
> > -               else if (dwc->dma_sconfig.direction == DMA_DEV_TO_MEM)
> > +               else if (dwc->direction == DMA_DEV_TO_MEM)
> >                         cfghi = DWC_CFGH_SRC_PER(dwc->dma_sconfig.slave_id);
> >         }
> 
> I have a doubt here. This routine is called both for memcpy and slave transfers.
> Earlier if (dws), code was used to check slave/non-slave transfer but with your
> earlier patch, for if (!dws) case too, there can be slave transfers
> based on direction.
> 
> Consider a situation. A channel is used for slave transfers and have
> direction set
> to DMA_DEV_TO_MEM. Now, channel is freed and used for memcpy. Now the
> direction value is retained as we haven't updated it. So, is this a
> potential bug?

Yeah, good point. I think we have to set direction in all possible entry
points (prep functions only?). It means at least we need to update
memcpy prep as well.

I'll update patch tomorrow.

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy