dmaengine: of_dma: Support for DMA routers (56f13c0d) · Commits · 戴 / test

Documentation/devicetree/bindings/dma/dma.txt

+28 −0

Original line number	Diff line number	Diff line
		@@ -31,6 +31,34 @@ Example:
		dma-requests = <127>;
		};

		* DMA router

		DMA routers are transparent IP blocks used to route DMA request lines from
		devices to the DMA controller. Some SoCs (like TI DRA7x) have more peripherals
		integrated with DMA requests than what the DMA controller can handle directly.

		Required property:
		- dma-masters: phandle of the DMA controller or list of phandles for
		the DMA controllers the router can direct the signal to.
		- #dma-cells: Must be at least 1. Used to provide DMA router specific
		information. See DMA client binding below for more
		details.

		Optional properties:
		- dma-requests: Number of incoming request lines the router can handle.
		- In the node pointed by the dma-masters:
		- dma-requests: The router driver might need to look for this in order
		to configure the routing.

		Example:
		sdma_xbar: dma-router@4a002b78 {
		compatible = "ti,dra7-dma-crossbar";
		reg = <0x4a002b78 0xfc>;
		#dma-cells = <1>;
		dma-requests = <205>;
		ti,dma-safe-map = <0>;
		dma-masters = <&sdma>;
		};

		* DMA client

drivers/dma/dmaengine.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -267,6 +267,13 @@ static void dma_chan_put(struct dma_chan *chan)
		/* This channel is not in use anymore, free it */
		if (!chan->client_count && chan->device->device_free_chan_resources)
		chan->device->device_free_chan_resources(chan);

		/* If the channel is used via a DMA request router, free the mapping */
		if (chan->router && chan->router->route_free) {
		chan->router->route_free(chan->router->dev, chan->route_data);
		chan->router = NULL;
		chan->route_data = NULL;
		}
		}

		enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)

drivers/dma/of-dma.c

+89 −0

Original line number	Diff line number	Diff line
		@@ -44,6 +44,50 @@ static struct of_dma of_dma_find_controller(struct of_phandle_args dma_spec)
		return NULL;
		}

		/**
		* of_dma_router_xlate - translation function for router devices
		* @dma_spec: pointer to DMA specifier as found in the device tree
		* @of_dma: pointer to DMA controller data (router information)
		*
		* The function creates new dma_spec to be passed to the router driver's
		* of_dma_route_allocate() function to prepare a dma_spec which will be used
		* to request channel from the real DMA controller.
		*/
		static struct dma_chan of_dma_router_xlate(struct of_phandle_args dma_spec,
		struct of_dma *ofdma)
		{
		struct dma_chan *chan;
		struct of_dma *ofdma_target;
		struct of_phandle_args dma_spec_target;
		void *route_data;

		/* translate the request for the real DMA controller */
		memcpy(&dma_spec_target, dma_spec, sizeof(dma_spec_target));
		route_data = ofdma->of_dma_route_allocate(&dma_spec_target, ofdma);
		if (IS_ERR(route_data))
		return NULL;

		ofdma_target = of_dma_find_controller(&dma_spec_target);
		if (!ofdma_target)
		return NULL;

		chan = ofdma_target->of_dma_xlate(&dma_spec_target, ofdma_target);
		if (chan) {
		chan->router = ofdma->dma_router;
		chan->route_data = route_data;
		} else {
		ofdma->dma_router->route_free(ofdma->dma_router->dev,
		route_data);
		}

		/*
		* Need to put the node back since the ofdma->of_dma_route_allocate
		* has taken it for generating the new, translated dma_spec
		*/
		of_node_put(dma_spec_target.np);
		return chan;
		}

		/**
		* of_dma_controller_register - Register a DMA controller to DT DMA helpers
		* @np: device node of DMA controller
		@@ -109,6 +153,51 @@ void of_dma_controller_free(struct device_node *np)
		}
		EXPORT_SYMBOL_GPL(of_dma_controller_free);

		/**
		* of_dma_router_register - Register a DMA router to DT DMA helpers as a
		* controller
		* @np: device node of DMA router
		* @of_dma_route_allocate: setup function for the router which need to
		* modify the dma_spec for the DMA controller to
		* use and to set up the requested route.
		* @dma_router: pointer to dma_router structure to be used when
		* the route need to be free up.
		*
		* Returns 0 on success or appropriate errno value on error.
		*
		* Allocated memory should be freed with appropriate of_dma_controller_free()
		* call.
		*/
		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)
		{
		struct of_dma *ofdma;

		if (!np \|\| !of_dma_route_allocate \|\| !dma_router) {
		pr_err("%s: not enough information provided\n", __func__);
		return -EINVAL;
		}

		ofdma = kzalloc(sizeof(*ofdma), GFP_KERNEL);
		if (!ofdma)
		return -ENOMEM;

		ofdma->of_node = np;
		ofdma->of_dma_xlate = of_dma_router_xlate;
		ofdma->of_dma_route_allocate = of_dma_route_allocate;
		ofdma->dma_router = dma_router;

		/* Now queue of_dma controller structure in list */
		mutex_lock(&of_dma_lock);
		list_add_tail(&ofdma->of_dma_controllers, &of_dma_list);
		mutex_unlock(&of_dma_lock);

		return 0;
		}
		EXPORT_SYMBOL_GPL(of_dma_router_register);

		/**
		* of_dma_match_channel - Check if a DMA specifier matches name
		* @np: device node to look for DMA channels

include/linux/dmaengine.h

+17 −0

Original line number	Diff line number	Diff line
		@@ -221,6 +221,16 @@ struct dma_chan_percpu {
		unsigned long bytes_transferred;
		};

		/**
		* struct dma_router - DMA router structure
		* @dev: pointer to the DMA router device
		* @route_free: function to be called when the route can be disconnected
		*/
		struct dma_router {
		struct device *dev;
		void (route_free)(struct device dev, void *route_data);
		};

		/**
		* struct dma_chan - devices supply DMA channels, clients use them
		* @device: ptr to the dma device who supplies this channel, always !%NULL
		@@ -232,6 +242,8 @@ struct dma_chan_percpu {
		* @local: per-cpu pointer to a struct dma_chan_percpu
		* @client_count: how many clients are using this channel
		* @table_count: number of appearances in the mem-to-mem allocation table
		* @router: pointer to the DMA router structure
		* @route_data: channel specific data for the router
		* @private: private data for certain client-channel associations
		*/
		struct dma_chan {
		@@ -247,6 +259,11 @@ struct dma_chan {
		struct dma_chan_percpu __percpu *local;
		int client_count;
		int table_count;

		/* DMA router */
		struct dma_router *router;
		void *route_data;

		void *private;
		};

include/linux/of_dma.h

+21 −0

Original line number	Diff line number	Diff line
		@@ -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)
		{

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