1 // SPDX-License-Identifier: GPL-2.0-only
3  * Device tree helpers for DMA request / controller
7  * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
24  * of_dma_find_controller - Get a DMA controller in DT DMA helpers list
25  * @dma_spec:	pointer to DMA specifier as found in the device tree
27  * Finds a DMA controller with matching device node and number for dma cells
28  * in a list of registered DMA controllers. If a match is found a valid pointer
29  * to the DMA data stored is retuned. A NULL pointer is returned if no match is
37 		if (ofdma->of_node == dma_spec->np)  in of_dma_find_controller()
40 	pr_debug("%s: can't find DMA controller %pOF\n", __func__,  in of_dma_find_controller()
41 		 dma_spec->np);  in of_dma_find_controller()
47  * of_dma_router_xlate - translation function for router devices
48  * @dma_spec:	pointer to DMA specifier as found in the device tree
49  * @ofdma:	pointer to DMA controller data (router information)
51  * The function creates new dma_spec to be passed to the router driver's
53  * to request channel from the real DMA controller.
63 	/* translate the request for the real DMA controller */  in of_dma_router_xlate()
65 	route_data = ofdma->of_dma_route_allocate(&dma_spec_target, ofdma);  in of_dma_router_xlate()
73 	chan = ofdma_target->of_dma_xlate(&dma_spec_target, ofdma_target);  in of_dma_router_xlate()
75 		ofdma->dma_router->route_free(ofdma->dma_router->dev,  in of_dma_router_xlate()
78 		chan->router = ofdma->dma_router;  in of_dma_router_xlate()
79 		chan->route_data = route_data;  in of_dma_router_xlate()
83 	 * Need to put the node back since the ofdma->of_dma_route_allocate  in of_dma_router_xlate()
91  * of_dma_controller_register - Register a DMA controller to DT DMA helpers
92  * @np:			device node of DMA controller
112 		return -EINVAL;  in of_dma_controller_register()
117 		return -ENOMEM;  in of_dma_controller_register()
119 	ofdma->of_node = np;  in of_dma_controller_register()
120 	ofdma->of_dma_xlate = of_dma_xlate;  in of_dma_controller_register()
121 	ofdma->of_dma_data = data;  in of_dma_controller_register()
125 	list_add_tail(&ofdma->of_dma_controllers, &of_dma_list);  in of_dma_controller_register()
133  * of_dma_controller_free - Remove a DMA controller from DT DMA helpers list
134  * @np:		device node of DMA controller
145 		if (ofdma->of_node == np) {  in of_dma_controller_free()
146 			list_del(&ofdma->of_dma_controllers);  in of_dma_controller_free()
156  * of_dma_router_register - Register a DMA router to DT DMA helpers as a
158  * @np:				device node of DMA router
159  * @of_dma_route_allocate:	setup function for the router which need to
160  *				modify the dma_spec for the DMA controller to
179 		return -EINVAL;  in of_dma_router_register()
184 		return -ENOMEM;  in of_dma_router_register()
186 	ofdma->of_node = np;  in of_dma_router_register()
187 	ofdma->of_dma_xlate = of_dma_router_xlate;  in of_dma_router_register()
188 	ofdma->of_dma_route_allocate = of_dma_route_allocate;  in of_dma_router_register()
189 	ofdma->dma_router = dma_router;  in of_dma_router_register()
193 	list_add_tail(&ofdma->of_dma_controllers, &of_dma_list);  in of_dma_router_register()
201  * of_dma_match_channel - Check if a DMA specifier matches name
202  * @np:		device node to look for DMA channels
204  * @index:	index of DMA specifier in list of DMA specifiers
205  * @dma_spec:	pointer to DMA specifier as found in the device tree
207  * Check if the DMA specifier pointed to by the index in a list of DMA
209  * a valid pointer to the DMA specifier is found. Otherwise returns -ENODEV.
216 	if (of_property_read_string_index(np, "dma-names", index, &s))  in of_dma_match_channel()
217 		return -ENODEV;  in of_dma_match_channel()
220 		return -ENODEV;  in of_dma_match_channel()
222 	if (of_parse_phandle_with_args(np, "dmas", "#dma-cells", index,  in of_dma_match_channel()
224 		return -ENODEV;  in of_dma_match_channel()
230  * of_dma_request_slave_channel - Get the DMA slave channel
231  * @np:		device node to get DMA request from
234  * Returns pointer to appropriate DMA channel on success or an error pointer.
243 	int			ret_no_channel = -ENODEV;  in of_dma_request_slave_channel()
248 		return ERR_PTR(-ENODEV);  in of_dma_request_slave_channel()
253 		return ERR_PTR(-ENODEV);  in of_dma_request_slave_channel()
255 	count = of_property_count_strings(np, "dma-names");  in of_dma_request_slave_channel()
257 		pr_err("%s: dma-names property of node '%pOF' missing or empty\n",  in of_dma_request_slave_channel()
259 		return ERR_PTR(-ENODEV);  in of_dma_request_slave_channel()
277 			chan = ofdma->of_dma_xlate(&dma_spec, ofdma);  in of_dma_request_slave_channel()
279 			ret_no_channel = -EPROBE_DEFER;  in of_dma_request_slave_channel()
296  * of_dma_simple_xlate - Simple DMA engine translation function
297  * @dma_spec:	pointer to DMA specifier as found in the device tree
298  * @ofdma:	pointer to DMA controller data
300  * A simple translation function for devices that use a 32-bit value for the
301  * filter_param when calling the DMA engine dma_request_channel() function.
302  * Note that this translation function requires that #dma-cells is equal to 1
303  * and the argument of the dma specifier is the 32-bit filter_param. Returns
304  * pointer to appropriate dma channel on success or NULL on error.
309 	int count = dma_spec->args_count;  in of_dma_simple_xlate()
310 	struct of_dma_filter_info *info = ofdma->of_dma_data;  in of_dma_simple_xlate()
312 	if (!info || !info->filter_fn)  in of_dma_simple_xlate()
318 	return __dma_request_channel(&info->dma_cap, info->filter_fn,  in of_dma_simple_xlate()
319 				     &dma_spec->args[0], dma_spec->np);  in of_dma_simple_xlate()
324  * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
325  * @dma_spec:	pointer to DMA specifier as found in the device tree
326  * @ofdma:	pointer to DMA controller data
328  * This function can be used as the of xlate callback for DMA driver which wants
330  * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
334  * Returns pointer to appropriate dma channel on success or NULL on error.
339 	struct dma_device *dev = ofdma->of_dma_data;  in of_dma_xlate_by_chan_id()
342 	if (!dev || dma_spec->args_count != 1)  in of_dma_xlate_by_chan_id()
345 	list_for_each_entry(chan, &dev->channels, device_node)  in of_dma_xlate_by_chan_id()
346 		if (chan->chan_id == dma_spec->args[0]) {  in of_dma_xlate_by_chan_id()