On Wed, Apr 23, 2014 at 05:53:27PM +0400, Alexander Popov wrote: > This patch adds a new common OF dma xlate callback function which will match a > channel by it's id. The binding expects one integer argument which it will use to > lookup the channel by the id. > > Unlike of_dma_simple_xlate this function is able to handle a system with > multiple DMA controllers. When registering the of dma provider with > of_dma_controller_register a pointer to the dma_device struct which is > associated with the dt node needs to passed as the data parameter. > New function will use this pointer to match only channels which belong to the > specified DMA controller. This patch needs review by DT folks too > > Signed-off-by: Alexander Popov <a13xp0p0v88@xxxxxxxxx> > --- > drivers/dma/of-dma.c | 35 +++++++++++++++++++++++++++++++++++ > include/linux/of_dma.h | 4 ++++ > 2 files changed, 39 insertions(+) > > diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c > index e8fe9dc..d5fbeaa 100644 > --- a/drivers/dma/of-dma.c > +++ b/drivers/dma/of-dma.c > @@ -218,3 +218,38 @@ struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec, > &dma_spec->args[0]); > } > EXPORT_SYMBOL_GPL(of_dma_simple_xlate); > + > +/** > + * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id > + * @dma_spec: pointer to DMA specifier as found in the device tree > + * @of_dma: pointer to DMA controller data > + * > + * This function can be used as the of xlate callback for DMA driver which wants > + * to match the channel based on the channel id. When using this xlate function > + * the #dma-cells propety of the DMA controller dt node needs to be set to 1. > + * The data parameter of of_dma_controller_register must be a pointer to the > + * dma_device struct the function should match upon. > + * > + * Returns pointer to appropriate dma channel on success or NULL on error. > + */ > +struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec, > + struct of_dma *ofdma) > +{ > + struct dma_device *dev = ofdma->of_dma_data; > + struct dma_chan *chan, *candidate = NULL; > + > + if (!dev || dma_spec->args_count != 1) > + return NULL; > + > + list_for_each_entry(chan, &dev->channels, device_node) > + if (chan->chan_id == dma_spec->args[0]) { > + candidate = chan; > + break; > + } > + > + if (!candidate) > + return NULL; > + > + return dma_get_slave_channel(candidate); > +} > +EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id); > diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h > index ae36298..56bc026 100644 > --- a/include/linux/of_dma.h > +++ b/include/linux/of_dma.h > @@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct device_node *np, > const char *name); > extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec, > struct of_dma *ofdma); > +extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec, > + struct of_dma *ofdma); > #else > static inline int of_dma_controller_register(struct device_node *np, > struct dma_chan *(*of_dma_xlate) > @@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_s > return NULL; > } > > +#define of_dma_xlate_by_chan_id NULL > + > #endif > > #endif /* __LINUX_OF_DMA_H */ > -- > 1.8.4.2 > -- -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html