| Message ID | 20200528222401.26941-6-Sergey.Semin@baikalelectronics.ru (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | dmaengine: dw: Take Baikal-T1 SoC DW DMAC peculiarities into account | expand |
On Fri, May 29, 2020 at 01:23:55AM +0300, Serge Semin wrote: > There are DMA devices (like ours version of Synopsys DW DMAC) which have > DMA capabilities non-uniformly redistributed amongst the device channels. > In order to provide a way of exposing the channel-specific parameters to > the DMA engine consumers, we introduce a new DMA-device callback. In case > if provided it gets called from the dma_get_slave_caps() method and is > able to override the generic DMA-device capabilities. I thought there is a pattern to return something, but it seems none. So, I have nothing against it to return void. Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> But consider one comment below. > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> > Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> > Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> > Cc: Arnd Bergmann <arnd@arndb.de> > Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > Cc: Rob Herring <robh+dt@kernel.org> > Cc: linux-mips@vger.kernel.org > Cc: devicetree@vger.kernel.org > > --- > > Changelog v3: > - This is a new patch created as a result of the discussion with Vinod and > Andy in the framework of DW DMA burst and LLP capabilities. > --- > drivers/dma/dmaengine.c | 3 +++ > include/linux/dmaengine.h | 2 ++ > 2 files changed, 5 insertions(+) > > diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c > index ad56ad58932c..edbb11d56cde 100644 > --- a/drivers/dma/dmaengine.c > +++ b/drivers/dma/dmaengine.c > @@ -599,6 +599,9 @@ int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps) > caps->cmd_resume = !!device->device_resume; > caps->cmd_terminate = !!device->device_terminate_all; > Perhaps a comment to explain that this is channel specific correction / override / you name it on top of device level capabilities? > + if (device->device_caps) > + device->device_caps(chan, caps); > + > return 0; > } > EXPORT_SYMBOL_GPL(dma_get_slave_caps); > diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h > index a7e4d8dfdd19..b303e59929e5 100644 > --- a/include/linux/dmaengine.h > +++ b/include/linux/dmaengine.h > @@ -899,6 +899,8 @@ struct dma_device { > struct dma_chan *chan, dma_addr_t dst, u64 data, > unsigned long flags); > > + void (*device_caps)(struct dma_chan *chan, > + struct dma_slave_caps *caps); > int (*device_config)(struct dma_chan *chan, > struct dma_slave_config *config); > int (*device_pause)(struct dma_chan *chan); > -- > 2.26.2 >
On Fri, May 29, 2020 at 03:12:03PM +0300, Andy Shevchenko wrote: > On Fri, May 29, 2020 at 01:23:55AM +0300, Serge Semin wrote: > > There are DMA devices (like ours version of Synopsys DW DMAC) which have > > DMA capabilities non-uniformly redistributed amongst the device channels. > > In order to provide a way of exposing the channel-specific parameters to > > the DMA engine consumers, we introduce a new DMA-device callback. In case > > if provided it gets called from the dma_get_slave_caps() method and is > > able to override the generic DMA-device capabilities. > > I thought there is a pattern to return something, but it seems none. > So, I have nothing against it to return void. > > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > > But consider one comment below. > > > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> > > Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> > > Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> > > Cc: Arnd Bergmann <arnd@arndb.de> > > Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > > Cc: Rob Herring <robh+dt@kernel.org> > > Cc: linux-mips@vger.kernel.org > > Cc: devicetree@vger.kernel.org > > > > --- > > > > Changelog v3: > > - This is a new patch created as a result of the discussion with Vinod and > > Andy in the framework of DW DMA burst and LLP capabilities. > > --- > > drivers/dma/dmaengine.c | 3 +++ > > include/linux/dmaengine.h | 2 ++ > > 2 files changed, 5 insertions(+) > > > > diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c > > index ad56ad58932c..edbb11d56cde 100644 > > --- a/drivers/dma/dmaengine.c > > +++ b/drivers/dma/dmaengine.c > > @@ -599,6 +599,9 @@ int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps) > > caps->cmd_resume = !!device->device_resume; > > caps->cmd_terminate = !!device->device_terminate_all; > > > > Perhaps a comment to explain that this is channel specific correction / > override / you name it on top of device level capabilities? > > > + if (device->device_caps) > > + device->device_caps(chan, caps); > > + Agreed. I also forgot to add a doc-comment above the struct dma_device definition. -Sergey > > return 0; > > } > > EXPORT_SYMBOL_GPL(dma_get_slave_caps); > > diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h > > index a7e4d8dfdd19..b303e59929e5 100644 > > --- a/include/linux/dmaengine.h > > +++ b/include/linux/dmaengine.h > > @@ -899,6 +899,8 @@ struct dma_device { > > struct dma_chan *chan, dma_addr_t dst, u64 data, > > unsigned long flags); > > > > + void (*device_caps)(struct dma_chan *chan, > > + struct dma_slave_caps *caps); > > int (*device_config)(struct dma_chan *chan, > > struct dma_slave_config *config); > > int (*device_pause)(struct dma_chan *chan); > > -- > > 2.26.2 > > > > -- > With Best Regards, > Andy Shevchenko > >
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index ad56ad58932c..edbb11d56cde 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -599,6 +599,9 @@ int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps) caps->cmd_resume = !!device->device_resume; caps->cmd_terminate = !!device->device_terminate_all; + if (device->device_caps) + device->device_caps(chan, caps); + return 0; } EXPORT_SYMBOL_GPL(dma_get_slave_caps); diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index a7e4d8dfdd19..b303e59929e5 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -899,6 +899,8 @@ struct dma_device { struct dma_chan *chan, dma_addr_t dst, u64 data, unsigned long flags); + void (*device_caps)(struct dma_chan *chan, + struct dma_slave_caps *caps); int (*device_config)(struct dma_chan *chan, struct dma_slave_config *config); int (*device_pause)(struct dma_chan *chan);
There are DMA devices (like ours version of Synopsys DW DMAC) which have DMA capabilities non-uniformly redistributed amongst the device channels. In order to provide a way of exposing the channel-specific parameters to the DMA engine consumers, we introduce a new DMA-device callback. In case if provided it gets called from the dma_get_slave_caps() method and is able to override the generic DMA-device capabilities. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org --- Changelog v3: - This is a new patch created as a result of the discussion with Vinod and Andy in the framework of DW DMA burst and LLP capabilities. --- drivers/dma/dmaengine.c | 3 +++ include/linux/dmaengine.h | 2 ++ 2 files changed, 5 insertions(+)