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Andy Shevchenko1b2e98b2013-04-09 14:05:43 +03001/*
2 * ACPI helpers for DMA request / controller
3 *
4 * Based on of-dma.c
5 *
6 * Copyright (C) 2013, Intel Corporation
Andy Shevchenkoee8209f2013-05-08 11:55:48 +03007 * Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
8 * Mika Westerberg <mika.westerberg@linux.intel.com>
Andy Shevchenko1b2e98b2013-04-09 14:05:43 +03009 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 */
14
15#include <linux/device.h>
16#include <linux/module.h>
17#include <linux/list.h>
18#include <linux/mutex.h>
19#include <linux/slab.h>
Andy Shevchenkoee8209f2013-05-08 11:55:48 +030020#include <linux/ioport.h>
Andy Shevchenko1b2e98b2013-04-09 14:05:43 +030021#include <linux/acpi.h>
22#include <linux/acpi_dma.h>
23
24static LIST_HEAD(acpi_dma_list);
25static DEFINE_MUTEX(acpi_dma_lock);
26
27/**
Andy Shevchenkoee8209f2013-05-08 11:55:48 +030028 * acpi_dma_parse_resource_group - match device and parse resource group
29 * @grp: CSRT resource group
30 * @adev: ACPI device to match with
31 * @adma: struct acpi_dma of the given DMA controller
32 *
33 * Returns 1 on success, 0 when no information is available, or appropriate
34 * errno value on error.
35 *
36 * In order to match a device from DSDT table to the corresponding CSRT device
37 * we use MMIO address and IRQ.
38 */
39static int acpi_dma_parse_resource_group(const struct acpi_csrt_group *grp,
40 struct acpi_device *adev, struct acpi_dma *adma)
41{
42 const struct acpi_csrt_shared_info *si;
43 struct list_head resource_list;
44 struct resource_list_entry *rentry;
45 resource_size_t mem = 0, irq = 0;
Andy Shevchenkoee8209f2013-05-08 11:55:48 +030046 int ret;
47
48 if (grp->shared_info_length != sizeof(struct acpi_csrt_shared_info))
49 return -ENODEV;
50
51 INIT_LIST_HEAD(&resource_list);
52 ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
53 if (ret <= 0)
54 return 0;
55
56 list_for_each_entry(rentry, &resource_list, node) {
57 if (resource_type(&rentry->res) == IORESOURCE_MEM)
58 mem = rentry->res.start;
59 else if (resource_type(&rentry->res) == IORESOURCE_IRQ)
60 irq = rentry->res.start;
61 }
62
63 acpi_dev_free_resource_list(&resource_list);
64
65 /* Consider initial zero values as resource not found */
66 if (mem == 0 && irq == 0)
67 return 0;
68
69 si = (const struct acpi_csrt_shared_info *)&grp[1];
70
71 /* Match device by MMIO and IRQ */
72 if (si->mmio_base_low != mem || si->gsi_interrupt != irq)
73 return 0;
74
Andy Shevchenkoee8209f2013-05-08 11:55:48 +030075 dev_dbg(&adev->dev, "matches with %.4s%04X (rev %u)\n",
Andy Shevchenkob4d6d332013-08-21 14:27:06 +030076 (char *)&grp->vendor_id, grp->device_id, grp->revision);
Andy Shevchenkoee8209f2013-05-08 11:55:48 +030077
78 /* Check if the request line range is available */
79 if (si->base_request_line == 0 && si->num_handshake_signals == 0)
80 return 0;
81
82 adma->base_request_line = si->base_request_line;
83 adma->end_request_line = si->base_request_line +
84 si->num_handshake_signals - 1;
85
86 dev_dbg(&adev->dev, "request line base: 0x%04x end: 0x%04x\n",
87 adma->base_request_line, adma->end_request_line);
88
89 return 1;
90}
91
92/**
93 * acpi_dma_parse_csrt - parse CSRT to exctract additional DMA resources
94 * @adev: ACPI device to match with
95 * @adma: struct acpi_dma of the given DMA controller
96 *
97 * CSRT or Core System Resources Table is a proprietary ACPI table
98 * introduced by Microsoft. This table can contain devices that are not in
99 * the system DSDT table. In particular DMA controllers might be described
100 * here.
101 *
102 * We are using this table to get the request line range of the specific DMA
103 * controller to be used later.
104 *
105 */
106static void acpi_dma_parse_csrt(struct acpi_device *adev, struct acpi_dma *adma)
107{
108 struct acpi_csrt_group *grp, *end;
109 struct acpi_table_csrt *csrt;
110 acpi_status status;
111 int ret;
112
113 status = acpi_get_table(ACPI_SIG_CSRT, 0,
114 (struct acpi_table_header **)&csrt);
115 if (ACPI_FAILURE(status)) {
116 if (status != AE_NOT_FOUND)
117 dev_warn(&adev->dev, "failed to get the CSRT table\n");
118 return;
119 }
120
121 grp = (struct acpi_csrt_group *)(csrt + 1);
122 end = (struct acpi_csrt_group *)((void *)csrt + csrt->header.length);
123
124 while (grp < end) {
125 ret = acpi_dma_parse_resource_group(grp, adev, adma);
126 if (ret < 0) {
127 dev_warn(&adev->dev,
128 "error in parsing resource group\n");
129 return;
130 }
131
132 grp = (struct acpi_csrt_group *)((void *)grp + grp->length);
133 }
134}
135
136/**
Andy Shevchenko1b2e98b2013-04-09 14:05:43 +0300137 * acpi_dma_controller_register - Register a DMA controller to ACPI DMA helpers
138 * @dev: struct device of DMA controller
139 * @acpi_dma_xlate: translation function which converts a dma specifier
140 * into a dma_chan structure
141 * @data pointer to controller specific data to be used by
142 * translation function
143 *
144 * Returns 0 on success or appropriate errno value on error.
145 *
146 * Allocated memory should be freed with appropriate acpi_dma_controller_free()
147 * call.
148 */
149int acpi_dma_controller_register(struct device *dev,
150 struct dma_chan *(*acpi_dma_xlate)
151 (struct acpi_dma_spec *, struct acpi_dma *),
152 void *data)
153{
154 struct acpi_device *adev;
155 struct acpi_dma *adma;
156
157 if (!dev || !acpi_dma_xlate)
158 return -EINVAL;
159
160 /* Check if the device was enumerated by ACPI */
161 if (!ACPI_HANDLE(dev))
162 return -EINVAL;
163
164 if (acpi_bus_get_device(ACPI_HANDLE(dev), &adev))
165 return -EINVAL;
166
167 adma = kzalloc(sizeof(*adma), GFP_KERNEL);
168 if (!adma)
169 return -ENOMEM;
170
171 adma->dev = dev;
172 adma->acpi_dma_xlate = acpi_dma_xlate;
173 adma->data = data;
174
Andy Shevchenkoee8209f2013-05-08 11:55:48 +0300175 acpi_dma_parse_csrt(adev, adma);
176
Andy Shevchenko1b2e98b2013-04-09 14:05:43 +0300177 /* Now queue acpi_dma controller structure in list */
178 mutex_lock(&acpi_dma_lock);
179 list_add_tail(&adma->dma_controllers, &acpi_dma_list);
180 mutex_unlock(&acpi_dma_lock);
181
182 return 0;
183}
184EXPORT_SYMBOL_GPL(acpi_dma_controller_register);
185
186/**
187 * acpi_dma_controller_free - Remove a DMA controller from ACPI DMA helpers list
188 * @dev: struct device of DMA controller
189 *
190 * Memory allocated by acpi_dma_controller_register() is freed here.
191 */
192int acpi_dma_controller_free(struct device *dev)
193{
194 struct acpi_dma *adma;
195
196 if (!dev)
197 return -EINVAL;
198
199 mutex_lock(&acpi_dma_lock);
200
201 list_for_each_entry(adma, &acpi_dma_list, dma_controllers)
202 if (adma->dev == dev) {
203 list_del(&adma->dma_controllers);
204 mutex_unlock(&acpi_dma_lock);
205 kfree(adma);
206 return 0;
207 }
208
209 mutex_unlock(&acpi_dma_lock);
210 return -ENODEV;
211}
212EXPORT_SYMBOL_GPL(acpi_dma_controller_free);
213
214static void devm_acpi_dma_release(struct device *dev, void *res)
215{
216 acpi_dma_controller_free(dev);
217}
218
219/**
220 * devm_acpi_dma_controller_register - resource managed acpi_dma_controller_register()
221 * @dev: device that is registering this DMA controller
222 * @acpi_dma_xlate: translation function
223 * @data pointer to controller specific data
224 *
225 * Managed acpi_dma_controller_register(). DMA controller registered by this
226 * function are automatically freed on driver detach. See
227 * acpi_dma_controller_register() for more information.
228 */
229int devm_acpi_dma_controller_register(struct device *dev,
230 struct dma_chan *(*acpi_dma_xlate)
231 (struct acpi_dma_spec *, struct acpi_dma *),
232 void *data)
233{
234 void *res;
235 int ret;
236
237 res = devres_alloc(devm_acpi_dma_release, 0, GFP_KERNEL);
238 if (!res)
239 return -ENOMEM;
240
241 ret = acpi_dma_controller_register(dev, acpi_dma_xlate, data);
242 if (ret) {
243 devres_free(res);
244 return ret;
245 }
246 devres_add(dev, res);
247 return 0;
248}
249EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_register);
250
251/**
252 * devm_acpi_dma_controller_free - resource managed acpi_dma_controller_free()
253 *
254 * Unregister a DMA controller registered with
255 * devm_acpi_dma_controller_register(). Normally this function will not need to
256 * be called and the resource management code will ensure that the resource is
257 * freed.
258 */
259void devm_acpi_dma_controller_free(struct device *dev)
260{
261 WARN_ON(devres_destroy(dev, devm_acpi_dma_release, NULL, NULL));
262}
263EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_free);
264
Andy Shevchenkoee8209f2013-05-08 11:55:48 +0300265/**
266 * acpi_dma_update_dma_spec - prepare dma specifier to pass to translation function
267 * @adma: struct acpi_dma of DMA controller
268 * @dma_spec: dma specifier to update
269 *
270 * Returns 0, if no information is avaiable, -1 on mismatch, and 1 otherwise.
271 *
272 * Accordingly to ACPI 5.0 Specification Table 6-170 "Fixed DMA Resource
273 * Descriptor":
274 * DMA Request Line bits is a platform-relative number uniquely
275 * identifying the request line assigned. Request line-to-Controller
276 * mapping is done in a controller-specific OS driver.
277 * That's why we can safely adjust slave_id when the appropriate controller is
278 * found.
279 */
280static int acpi_dma_update_dma_spec(struct acpi_dma *adma,
281 struct acpi_dma_spec *dma_spec)
282{
283 /* Set link to the DMA controller device */
284 dma_spec->dev = adma->dev;
285
286 /* Check if the request line range is available */
287 if (adma->base_request_line == 0 && adma->end_request_line == 0)
288 return 0;
289
290 /* Check if slave_id falls to the range */
291 if (dma_spec->slave_id < adma->base_request_line ||
292 dma_spec->slave_id > adma->end_request_line)
293 return -1;
294
295 /*
296 * Here we adjust slave_id. It should be a relative number to the base
297 * request line.
298 */
299 dma_spec->slave_id -= adma->base_request_line;
300
301 return 1;
302}
303
Andy Shevchenko1b2e98b2013-04-09 14:05:43 +0300304struct acpi_dma_parser_data {
305 struct acpi_dma_spec dma_spec;
306 size_t index;
307 size_t n;
308};
309
310/**
311 * acpi_dma_parse_fixed_dma - Parse FixedDMA ACPI resources to a DMA specifier
312 * @res: struct acpi_resource to get FixedDMA resources from
313 * @data: pointer to a helper struct acpi_dma_parser_data
314 */
315static int acpi_dma_parse_fixed_dma(struct acpi_resource *res, void *data)
316{
317 struct acpi_dma_parser_data *pdata = data;
318
319 if (res->type == ACPI_RESOURCE_TYPE_FIXED_DMA) {
320 struct acpi_resource_fixed_dma *dma = &res->data.fixed_dma;
321
322 if (pdata->n++ == pdata->index) {
323 pdata->dma_spec.chan_id = dma->channels;
324 pdata->dma_spec.slave_id = dma->request_lines;
325 }
326 }
327
328 /* Tell the ACPI core to skip this resource */
329 return 1;
330}
331
332/**
333 * acpi_dma_request_slave_chan_by_index - Get the DMA slave channel
334 * @dev: struct device to get DMA request from
335 * @index: index of FixedDMA descriptor for @dev
336 *
337 * Returns pointer to appropriate dma channel on success or NULL on error.
338 */
339struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev,
340 size_t index)
341{
342 struct acpi_dma_parser_data pdata;
343 struct acpi_dma_spec *dma_spec = &pdata.dma_spec;
344 struct list_head resource_list;
345 struct acpi_device *adev;
346 struct acpi_dma *adma;
347 struct dma_chan *chan = NULL;
Andy Shevchenkoee8209f2013-05-08 11:55:48 +0300348 int found;
Andy Shevchenko1b2e98b2013-04-09 14:05:43 +0300349
350 /* Check if the device was enumerated by ACPI */
351 if (!dev || !ACPI_HANDLE(dev))
352 return NULL;
353
354 if (acpi_bus_get_device(ACPI_HANDLE(dev), &adev))
355 return NULL;
356
357 memset(&pdata, 0, sizeof(pdata));
358 pdata.index = index;
359
360 /* Initial values for the request line and channel */
361 dma_spec->chan_id = -1;
362 dma_spec->slave_id = -1;
363
364 INIT_LIST_HEAD(&resource_list);
365 acpi_dev_get_resources(adev, &resource_list,
366 acpi_dma_parse_fixed_dma, &pdata);
367 acpi_dev_free_resource_list(&resource_list);
368
369 if (dma_spec->slave_id < 0 || dma_spec->chan_id < 0)
370 return NULL;
371
372 mutex_lock(&acpi_dma_lock);
373
374 list_for_each_entry(adma, &acpi_dma_list, dma_controllers) {
Andy Shevchenkoee8209f2013-05-08 11:55:48 +0300375 /*
376 * We are not going to call translation function if slave_id
377 * doesn't fall to the request range.
378 */
379 found = acpi_dma_update_dma_spec(adma, dma_spec);
380 if (found < 0)
381 continue;
Andy Shevchenko1b2e98b2013-04-09 14:05:43 +0300382 chan = adma->acpi_dma_xlate(dma_spec, adma);
Andy Shevchenkoee8209f2013-05-08 11:55:48 +0300383 /*
384 * Try to get a channel only from the DMA controller that
385 * matches the slave_id. See acpi_dma_update_dma_spec()
386 * description for the details.
387 */
388 if (found > 0 || chan)
Andy Shevchenko1b2e98b2013-04-09 14:05:43 +0300389 break;
390 }
391
392 mutex_unlock(&acpi_dma_lock);
393 return chan;
394}
395EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_index);
396
397/**
398 * acpi_dma_request_slave_chan_by_name - Get the DMA slave channel
399 * @dev: struct device to get DMA request from
400 * @name: represents corresponding FixedDMA descriptor for @dev
401 *
402 * In order to support both Device Tree and ACPI in a single driver we
403 * translate the names "tx" and "rx" here based on the most common case where
404 * the first FixedDMA descriptor is TX and second is RX.
405 *
406 * Returns pointer to appropriate dma channel on success or NULL on error.
407 */
408struct dma_chan *acpi_dma_request_slave_chan_by_name(struct device *dev,
409 const char *name)
410{
411 size_t index;
412
413 if (!strcmp(name, "tx"))
414 index = 0;
415 else if (!strcmp(name, "rx"))
416 index = 1;
417 else
418 return NULL;
419
420 return acpi_dma_request_slave_chan_by_index(dev, index);
421}
422EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_name);
423
424/**
425 * acpi_dma_simple_xlate - Simple ACPI DMA engine translation helper
426 * @dma_spec: pointer to ACPI DMA specifier
427 * @adma: pointer to ACPI DMA controller data
428 *
429 * A simple translation function for ACPI based devices. Passes &struct
430 * dma_spec to the DMA controller driver provided filter function. Returns
431 * pointer to the channel if found or %NULL otherwise.
432 */
433struct dma_chan *acpi_dma_simple_xlate(struct acpi_dma_spec *dma_spec,
434 struct acpi_dma *adma)
435{
436 struct acpi_dma_filter_info *info = adma->data;
437
438 if (!info || !info->filter_fn)
439 return NULL;
440
441 return dma_request_channel(info->dma_cap, info->filter_fn, dma_spec);
442}
443EXPORT_SYMBOL_GPL(acpi_dma_simple_xlate);