This patch adds a new generic of dma xlate callback function which will match a channel by its id.
Signed-off-by: Lars-Peter Clausen <[email protected]> --- drivers/dma/of-dma.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/of_dma.h | 4 ++++ 2 files changed, 51 insertions(+) diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c index 00db454..7cad4d7 100644 --- a/drivers/dma/of-dma.c +++ b/drivers/dma/of-dma.c @@ -269,3 +269,50 @@ struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec, &dma_spec->args[0]); } EXPORT_SYMBOL_GPL(of_dma_simple_xlate); + +struct of_dma_filter_by_chan_id_args { + struct dma_device *dev; + unsigned int chan_id; +}; + +static bool of_dma_filter_by_chan_id(struct dma_chan *chan, void *params) +{ + struct of_dma_filter_by_chan_id_args *args = params; + + return chan->device == args->dev && chan->chan_id == args->chan_id; +} + +/** + * 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 want + * 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 uppon. + * + * 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 of_dma_filter_by_chan_id_args args; + dma_cap_mask_t cap; + + args.dev = ofdma->of_dma_data; + if (!args.dev) + return NULL; + + if (dma_spec->args_count != 1) + return NULL; + + dma_cap_zero(cap); + dma_cap_set(DMA_SLAVE, cap); + + args.chan_id = dma_spec->args[0]; + + return dma_request_channel(cap, of_dma_filter_by_chan_id, &args); +} +EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id); diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h index ce6a8ab..46732d3 100644 --- a/include/linux/of_dma.h +++ b/include/linux/of_dma.h @@ -43,6 +43,8 @@ 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) @@ -69,6 +71,8 @@ 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 */ -- 1.8.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
