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
/* 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)
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
}
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
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
* @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 {
struct dma_chan_percpu __percpu *local;
int client_count;
int table_count;
+
+ /* DMA router */
+ struct dma_router *router;
+ void *route_data;
+
void *private;
};
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;
};
(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)
{
}
+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)
{