Commit | Line | Data |
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1b2e98bc AS |
1 | /* |
2 | * ACPI helpers for DMA request / controller | |
3 | * | |
4 | * Based on of-dma.c | |
5 | * | |
6 | * Copyright (C) 2013, Intel Corporation | |
7 | * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com> | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License version 2 as | |
11 | * published by the Free Software Foundation. | |
12 | */ | |
13 | ||
14 | #include <linux/device.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/list.h> | |
17 | #include <linux/mutex.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/acpi.h> | |
20 | #include <linux/acpi_dma.h> | |
21 | ||
22 | static LIST_HEAD(acpi_dma_list); | |
23 | static DEFINE_MUTEX(acpi_dma_lock); | |
24 | ||
25 | /** | |
26 | * acpi_dma_controller_register - Register a DMA controller to ACPI DMA helpers | |
27 | * @dev: struct device of DMA controller | |
28 | * @acpi_dma_xlate: translation function which converts a dma specifier | |
29 | * into a dma_chan structure | |
30 | * @data pointer to controller specific data to be used by | |
31 | * translation function | |
32 | * | |
33 | * Returns 0 on success or appropriate errno value on error. | |
34 | * | |
35 | * Allocated memory should be freed with appropriate acpi_dma_controller_free() | |
36 | * call. | |
37 | */ | |
38 | int acpi_dma_controller_register(struct device *dev, | |
39 | struct dma_chan *(*acpi_dma_xlate) | |
40 | (struct acpi_dma_spec *, struct acpi_dma *), | |
41 | void *data) | |
42 | { | |
43 | struct acpi_device *adev; | |
44 | struct acpi_dma *adma; | |
45 | ||
46 | if (!dev || !acpi_dma_xlate) | |
47 | return -EINVAL; | |
48 | ||
49 | /* Check if the device was enumerated by ACPI */ | |
50 | if (!ACPI_HANDLE(dev)) | |
51 | return -EINVAL; | |
52 | ||
53 | if (acpi_bus_get_device(ACPI_HANDLE(dev), &adev)) | |
54 | return -EINVAL; | |
55 | ||
56 | adma = kzalloc(sizeof(*adma), GFP_KERNEL); | |
57 | if (!adma) | |
58 | return -ENOMEM; | |
59 | ||
60 | adma->dev = dev; | |
61 | adma->acpi_dma_xlate = acpi_dma_xlate; | |
62 | adma->data = data; | |
63 | ||
64 | /* Now queue acpi_dma controller structure in list */ | |
65 | mutex_lock(&acpi_dma_lock); | |
66 | list_add_tail(&adma->dma_controllers, &acpi_dma_list); | |
67 | mutex_unlock(&acpi_dma_lock); | |
68 | ||
69 | return 0; | |
70 | } | |
71 | EXPORT_SYMBOL_GPL(acpi_dma_controller_register); | |
72 | ||
73 | /** | |
74 | * acpi_dma_controller_free - Remove a DMA controller from ACPI DMA helpers list | |
75 | * @dev: struct device of DMA controller | |
76 | * | |
77 | * Memory allocated by acpi_dma_controller_register() is freed here. | |
78 | */ | |
79 | int acpi_dma_controller_free(struct device *dev) | |
80 | { | |
81 | struct acpi_dma *adma; | |
82 | ||
83 | if (!dev) | |
84 | return -EINVAL; | |
85 | ||
86 | mutex_lock(&acpi_dma_lock); | |
87 | ||
88 | list_for_each_entry(adma, &acpi_dma_list, dma_controllers) | |
89 | if (adma->dev == dev) { | |
90 | list_del(&adma->dma_controllers); | |
91 | mutex_unlock(&acpi_dma_lock); | |
92 | kfree(adma); | |
93 | return 0; | |
94 | } | |
95 | ||
96 | mutex_unlock(&acpi_dma_lock); | |
97 | return -ENODEV; | |
98 | } | |
99 | EXPORT_SYMBOL_GPL(acpi_dma_controller_free); | |
100 | ||
101 | static void devm_acpi_dma_release(struct device *dev, void *res) | |
102 | { | |
103 | acpi_dma_controller_free(dev); | |
104 | } | |
105 | ||
106 | /** | |
107 | * devm_acpi_dma_controller_register - resource managed acpi_dma_controller_register() | |
108 | * @dev: device that is registering this DMA controller | |
109 | * @acpi_dma_xlate: translation function | |
110 | * @data pointer to controller specific data | |
111 | * | |
112 | * Managed acpi_dma_controller_register(). DMA controller registered by this | |
113 | * function are automatically freed on driver detach. See | |
114 | * acpi_dma_controller_register() for more information. | |
115 | */ | |
116 | int devm_acpi_dma_controller_register(struct device *dev, | |
117 | struct dma_chan *(*acpi_dma_xlate) | |
118 | (struct acpi_dma_spec *, struct acpi_dma *), | |
119 | void *data) | |
120 | { | |
121 | void *res; | |
122 | int ret; | |
123 | ||
124 | res = devres_alloc(devm_acpi_dma_release, 0, GFP_KERNEL); | |
125 | if (!res) | |
126 | return -ENOMEM; | |
127 | ||
128 | ret = acpi_dma_controller_register(dev, acpi_dma_xlate, data); | |
129 | if (ret) { | |
130 | devres_free(res); | |
131 | return ret; | |
132 | } | |
133 | devres_add(dev, res); | |
134 | return 0; | |
135 | } | |
136 | EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_register); | |
137 | ||
138 | /** | |
139 | * devm_acpi_dma_controller_free - resource managed acpi_dma_controller_free() | |
140 | * | |
141 | * Unregister a DMA controller registered with | |
142 | * devm_acpi_dma_controller_register(). Normally this function will not need to | |
143 | * be called and the resource management code will ensure that the resource is | |
144 | * freed. | |
145 | */ | |
146 | void devm_acpi_dma_controller_free(struct device *dev) | |
147 | { | |
148 | WARN_ON(devres_destroy(dev, devm_acpi_dma_release, NULL, NULL)); | |
149 | } | |
150 | EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_free); | |
151 | ||
152 | struct acpi_dma_parser_data { | |
153 | struct acpi_dma_spec dma_spec; | |
154 | size_t index; | |
155 | size_t n; | |
156 | }; | |
157 | ||
158 | /** | |
159 | * acpi_dma_parse_fixed_dma - Parse FixedDMA ACPI resources to a DMA specifier | |
160 | * @res: struct acpi_resource to get FixedDMA resources from | |
161 | * @data: pointer to a helper struct acpi_dma_parser_data | |
162 | */ | |
163 | static int acpi_dma_parse_fixed_dma(struct acpi_resource *res, void *data) | |
164 | { | |
165 | struct acpi_dma_parser_data *pdata = data; | |
166 | ||
167 | if (res->type == ACPI_RESOURCE_TYPE_FIXED_DMA) { | |
168 | struct acpi_resource_fixed_dma *dma = &res->data.fixed_dma; | |
169 | ||
170 | if (pdata->n++ == pdata->index) { | |
171 | pdata->dma_spec.chan_id = dma->channels; | |
172 | pdata->dma_spec.slave_id = dma->request_lines; | |
173 | } | |
174 | } | |
175 | ||
176 | /* Tell the ACPI core to skip this resource */ | |
177 | return 1; | |
178 | } | |
179 | ||
180 | /** | |
181 | * acpi_dma_request_slave_chan_by_index - Get the DMA slave channel | |
182 | * @dev: struct device to get DMA request from | |
183 | * @index: index of FixedDMA descriptor for @dev | |
184 | * | |
185 | * Returns pointer to appropriate dma channel on success or NULL on error. | |
186 | */ | |
187 | struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev, | |
188 | size_t index) | |
189 | { | |
190 | struct acpi_dma_parser_data pdata; | |
191 | struct acpi_dma_spec *dma_spec = &pdata.dma_spec; | |
192 | struct list_head resource_list; | |
193 | struct acpi_device *adev; | |
194 | struct acpi_dma *adma; | |
195 | struct dma_chan *chan = NULL; | |
196 | ||
197 | /* Check if the device was enumerated by ACPI */ | |
198 | if (!dev || !ACPI_HANDLE(dev)) | |
199 | return NULL; | |
200 | ||
201 | if (acpi_bus_get_device(ACPI_HANDLE(dev), &adev)) | |
202 | return NULL; | |
203 | ||
204 | memset(&pdata, 0, sizeof(pdata)); | |
205 | pdata.index = index; | |
206 | ||
207 | /* Initial values for the request line and channel */ | |
208 | dma_spec->chan_id = -1; | |
209 | dma_spec->slave_id = -1; | |
210 | ||
211 | INIT_LIST_HEAD(&resource_list); | |
212 | acpi_dev_get_resources(adev, &resource_list, | |
213 | acpi_dma_parse_fixed_dma, &pdata); | |
214 | acpi_dev_free_resource_list(&resource_list); | |
215 | ||
216 | if (dma_spec->slave_id < 0 || dma_spec->chan_id < 0) | |
217 | return NULL; | |
218 | ||
219 | mutex_lock(&acpi_dma_lock); | |
220 | ||
221 | list_for_each_entry(adma, &acpi_dma_list, dma_controllers) { | |
222 | dma_spec->dev = adma->dev; | |
223 | chan = adma->acpi_dma_xlate(dma_spec, adma); | |
224 | if (chan) | |
225 | break; | |
226 | } | |
227 | ||
228 | mutex_unlock(&acpi_dma_lock); | |
229 | return chan; | |
230 | } | |
231 | EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_index); | |
232 | ||
233 | /** | |
234 | * acpi_dma_request_slave_chan_by_name - Get the DMA slave channel | |
235 | * @dev: struct device to get DMA request from | |
236 | * @name: represents corresponding FixedDMA descriptor for @dev | |
237 | * | |
238 | * In order to support both Device Tree and ACPI in a single driver we | |
239 | * translate the names "tx" and "rx" here based on the most common case where | |
240 | * the first FixedDMA descriptor is TX and second is RX. | |
241 | * | |
242 | * Returns pointer to appropriate dma channel on success or NULL on error. | |
243 | */ | |
244 | struct dma_chan *acpi_dma_request_slave_chan_by_name(struct device *dev, | |
245 | const char *name) | |
246 | { | |
247 | size_t index; | |
248 | ||
249 | if (!strcmp(name, "tx")) | |
250 | index = 0; | |
251 | else if (!strcmp(name, "rx")) | |
252 | index = 1; | |
253 | else | |
254 | return NULL; | |
255 | ||
256 | return acpi_dma_request_slave_chan_by_index(dev, index); | |
257 | } | |
258 | EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_name); | |
259 | ||
260 | /** | |
261 | * acpi_dma_simple_xlate - Simple ACPI DMA engine translation helper | |
262 | * @dma_spec: pointer to ACPI DMA specifier | |
263 | * @adma: pointer to ACPI DMA controller data | |
264 | * | |
265 | * A simple translation function for ACPI based devices. Passes &struct | |
266 | * dma_spec to the DMA controller driver provided filter function. Returns | |
267 | * pointer to the channel if found or %NULL otherwise. | |
268 | */ | |
269 | struct dma_chan *acpi_dma_simple_xlate(struct acpi_dma_spec *dma_spec, | |
270 | struct acpi_dma *adma) | |
271 | { | |
272 | struct acpi_dma_filter_info *info = adma->data; | |
273 | ||
274 | if (!info || !info->filter_fn) | |
275 | return NULL; | |
276 | ||
277 | return dma_request_channel(info->dma_cap, info->filter_fn, dma_spec); | |
278 | } | |
279 | EXPORT_SYMBOL_GPL(acpi_dma_simple_xlate); |