Message ID | 1383290374-17484-4-git-send-email-a13xp0p0v88@gmail.com (mailing list archive) |
---|---|
State | Superseded |
Delegated to: | Anatolij Gustschin |
Headers | show |
On Friday 01 November 2013, Alexander Popov wrote: > + * 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 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); This seems rather clumsy, now that we have added the dma_get_slave_channel interface. Can you try using that instead of dma_request_channel() now?
2013/11/1 Arnd Bergmann <arnd@arndb.de>: > On Friday 01 November 2013, Alexander Popov wrote: >> + * 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 seems rather clumsy, now that we have added the dma_get_slave_channel interface. > Can you try using that instead of dma_request_channel() now? > Thanks, Arnd. I'll return with the fixed version. Best regards, Alexander.
diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c index 0b88dd3..aa9c425 100644 --- a/drivers/dma/of-dma.c +++ b/drivers/dma/of-dma.c @@ -215,3 +215,50 @@ 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 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 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 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 */