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
27  * Finds a DMA controller with matching device node and number for dma cells
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
49  * @ofdma:	pointer to DMA controller data (router information)
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()
71 		ofdma->dma_router->route_free(ofdma->dma_router->dev,  in of_dma_router_xlate()
73 		chan = ERR_PTR(-EPROBE_DEFER);  in of_dma_router_xlate()
77 	chan = ofdma_target->of_dma_xlate(&dma_spec_target, ofdma_target);  in of_dma_router_xlate()
79 		ofdma->dma_router->route_free(ofdma->dma_router->dev,  in of_dma_router_xlate()
82 		chan->router = ofdma->dma_router;  in of_dma_router_xlate()
83 		chan->route_data = route_data;  in of_dma_router_xlate()
88 	 * Need to put the node back since the ofdma->of_dma_route_allocate  in of_dma_router_xlate()
96  * of_dma_controller_register - Register a DMA controller to DT DMA helpers
97  * @np:			device node of DMA controller
100  * @data:		pointer to controller specific data to be used by
111 				void *data)  in of_dma_controller_register()  argument
117 		return -EINVAL;  in of_dma_controller_register()
122 		return -ENOMEM;  in of_dma_controller_register()
124 	ofdma->of_node = np;  in of_dma_controller_register()
125 	ofdma->of_dma_xlate = of_dma_xlate;  in of_dma_controller_register()
126 	ofdma->of_dma_data = data;  in of_dma_controller_register()
128 	/* Now queue of_dma controller structure in list */  in of_dma_controller_register()
130 	list_add_tail(&ofdma->of_dma_controllers, &of_dma_list);  in of_dma_controller_register()
138  * of_dma_controller_free - Remove a DMA controller from DT DMA helpers list
139  * @np:		device node of DMA controller
150 		if (ofdma->of_node == np) {  in of_dma_controller_free()
151 			list_del(&ofdma->of_dma_controllers);  in of_dma_controller_free()
161  * of_dma_router_register - Register a DMA router to DT DMA helpers as a
162  *			    controller
165  *				modify the dma_spec for the DMA controller to
184 		return -EINVAL;  in of_dma_router_register()
189 		return -ENOMEM;  in of_dma_router_register()
191 	ofdma->of_node = np;  in of_dma_router_register()
192 	ofdma->of_dma_xlate = of_dma_router_xlate;  in of_dma_router_register()
193 	ofdma->of_dma_route_allocate = of_dma_route_allocate;  in of_dma_router_register()
194 	ofdma->dma_router = dma_router;  in of_dma_router_register()
196 	/* Now queue of_dma controller structure in list */  in of_dma_router_register()
198 	list_add_tail(&ofdma->of_dma_controllers, &of_dma_list);  in of_dma_router_register()
206  * of_dma_match_channel - Check if a DMA specifier matches name
214  * a valid pointer to the DMA specifier is found. Otherwise returns -ENODEV.
221 	if (of_property_read_string_index(np, "dma-names", index, &s))  in of_dma_match_channel()
222 		return -ENODEV;  in of_dma_match_channel()
225 		return -ENODEV;  in of_dma_match_channel()
227 	if (of_parse_phandle_with_args(np, "dmas", "#dma-cells", index,  in of_dma_match_channel()
229 		return -ENODEV;  in of_dma_match_channel()
235  * of_dma_request_slave_channel - Get the DMA slave channel
248 	int			ret_no_channel = -ENODEV;  in of_dma_request_slave_channel()
253 		return ERR_PTR(-ENODEV);  in of_dma_request_slave_channel()
258 		return ERR_PTR(-ENODEV);  in of_dma_request_slave_channel()
260 	count = of_property_count_strings(np, "dma-names");  in of_dma_request_slave_channel()
262 		pr_err("%s: dma-names property of node '%pOF' missing or empty\n",  in of_dma_request_slave_channel()
264 		return ERR_PTR(-ENODEV);  in of_dma_request_slave_channel()
282 			chan = ofdma->of_dma_xlate(&dma_spec, ofdma);  in of_dma_request_slave_channel()
284 			ret_no_channel = -EPROBE_DEFER;  in of_dma_request_slave_channel()
301  * of_dma_simple_xlate - Simple DMA engine translation function
303  * @ofdma:	pointer to DMA controller data
305  * A simple translation function for devices that use a 32-bit value for the
307  * Note that this translation function requires that #dma-cells is equal to 1
308  * and the argument of the dma specifier is the 32-bit filter_param. Returns
314 	int count = dma_spec->args_count;  in of_dma_simple_xlate()
315 	struct of_dma_filter_info *info = ofdma->of_dma_data;  in of_dma_simple_xlate()
317 	if (!info || !info->filter_fn)  in of_dma_simple_xlate()
323 	return __dma_request_channel(&info->dma_cap, info->filter_fn,  in of_dma_simple_xlate()
324 				     &dma_spec->args[0], dma_spec->np);  in of_dma_simple_xlate()
329  * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
331  * @ofdma:	pointer to DMA controller data
335  * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
336  * The data parameter of of_dma_controller_register must be a pointer to the
344 	struct dma_device *dev = ofdma->of_dma_data;  in of_dma_xlate_by_chan_id()
347 	if (!dev || dma_spec->args_count != 1)  in of_dma_xlate_by_chan_id()
350 	list_for_each_entry(chan, &dev->channels, device_node)  in of_dma_xlate_by_chan_id()
351 		if (chan->chan_id == dma_spec->args[0]) {  in of_dma_xlate_by_chan_id()