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| author |   Peter Ujfalusi <peter.ujfalusi@ti.com> | 2015-04-09 12:35:47 +0300 |
|---|---|---|
| committer |   Vinod Koul <vinod.koul@intel.com> | 2015-05-09 17:11:25 +0530 |
| commit | 56f13c0d9524c5816f5dc9c91b9d766d6b1064ca (patch) | |
| tree | 4cdec4de3dbde9fd36d757f50e900811506969c7 /include/linux/of_dma.h | |
| parent | Linux 4.1-rc1 (diff) | |
| download | linux-dev-56f13c0d9524c5816f5dc9c91b9d766d6b1064ca.tar.xz linux-dev-56f13c0d9524c5816f5dc9c91b9d766d6b1064ca.zip | |
dmaengine: of_dma: Support for DMA routers
DMA routers are transparent devices used to mux DMA requests from
peripherals to DMA controllers. They are used when the SoC integrates more
devices with DMA requests then their controller can handle.
DRA7x is one example of such SoC, where the sDMA can hanlde 128 DMA request
lines, but in SoC level it has 205 DMA requests.
The of_dma_router will be registered as of_dma_controller with special
xlate function and additional parameters. The driver for the router is
responsible to craft the dma_spec (in the of_dma_route_allocate callback)
which can be used to requests a DMA channel from the real DMA controller.
This way the router can be transparent for the system while remaining generic
enough to be used in different environments.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'include/linux/of_dma.h')
| -rw-r--r-- | include/linux/of_dma.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h index 56bc026c143f..98ba7525929e 100644 --- a/include/linux/of_dma.h +++ b/include/linux/of_dma.h @@ -23,6 +23,9 @@ struct of_dma { struct device_node *of_node; struct dma_chan *(*of_dma_xlate) (struct of_phandle_args *, struct of_dma *); + void *(*of_dma_route_allocate) + (struct of_phandle_args *, struct of_dma *); + struct dma_router *dma_router; void *of_dma_data; }; @@ -37,12 +40,20 @@ extern int of_dma_controller_register(struct device_node *np, (struct of_phandle_args *, struct of_dma *), void *data); extern void of_dma_controller_free(struct device_node *np); + +extern int of_dma_router_register(struct device_node *np, + void *(*of_dma_route_allocate) + (struct of_phandle_args *, struct of_dma *), + struct dma_router *dma_router); +#define of_dma_router_free of_dma_controller_free + 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) @@ -56,6 +67,16 @@ static inline void of_dma_controller_free(struct device_node *np) { } +static inline int of_dma_router_register(struct device_node *np, + void *(*of_dma_route_allocate) + (struct of_phandle_args *, struct of_dma *), + struct dma_router *dma_router) +{ + return -ENODEV; +} + +#define of_dma_router_free of_dma_controller_free + static inline struct dma_chan *of_dma_request_slave_channel(struct device_node *np, const char *name) { |