xref: /openbmc/linux/drivers/dma/acpi-dma.c (revision 15cb0321)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * ACPI helpers for DMA request / controller
4  *
5  * Based on of-dma.c
6  *
7  * Copyright (C) 2013, Intel Corporation
8  * Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
9  *	    Mika Westerberg <mika.westerberg@linux.intel.com>
10  */
11 
12 #include <linux/device.h>
13 #include <linux/dma-mapping.h>
14 #include <linux/err.h>
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/list.h>
18 #include <linux/mutex.h>
19 #include <linux/slab.h>
20 #include <linux/ioport.h>
21 #include <linux/acpi.h>
22 #include <linux/acpi_dma.h>
23 #include <linux/property.h>
24 
25 static LIST_HEAD(acpi_dma_list);
26 static DEFINE_MUTEX(acpi_dma_lock);
27 
28 /**
29  * acpi_dma_parse_resource_group - match device and parse resource group
30  * @grp:	CSRT resource group
31  * @adev:	ACPI device to match with
32  * @adma:	struct acpi_dma of the given DMA controller
33  *
34  * In order to match a device from DSDT table to the corresponding CSRT device
35  * we use MMIO address and IRQ.
36  *
37  * Return:
38  * 1 on success, 0 when no information is available, or appropriate errno value
39  * on error.
40  */
acpi_dma_parse_resource_group(const struct acpi_csrt_group * grp,struct acpi_device * adev,struct acpi_dma * adma)41 static int acpi_dma_parse_resource_group(const struct acpi_csrt_group *grp,
42 		struct acpi_device *adev, struct acpi_dma *adma)
43 {
44 	const struct acpi_csrt_shared_info *si;
45 	struct list_head resource_list;
46 	struct resource_entry *rentry;
47 	resource_size_t mem = 0, irq = 0;
48 	int ret;
49 
50 	if (grp->shared_info_length != sizeof(struct acpi_csrt_shared_info))
51 		return -ENODEV;
52 
53 	INIT_LIST_HEAD(&resource_list);
54 	ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
55 	if (ret <= 0)
56 		return 0;
57 
58 	list_for_each_entry(rentry, &resource_list, node) {
59 		if (resource_type(rentry->res) == IORESOURCE_MEM)
60 			mem = rentry->res->start;
61 		else if (resource_type(rentry->res) == IORESOURCE_IRQ)
62 			irq = rentry->res->start;
63 	}
64 
65 	acpi_dev_free_resource_list(&resource_list);
66 
67 	/* Consider initial zero values as resource not found */
68 	if (mem == 0 && irq == 0)
69 		return 0;
70 
71 	si = (const struct acpi_csrt_shared_info *)&grp[1];
72 
73 	/* Match device by MMIO */
74 	if (si->mmio_base_low != lower_32_bits(mem) ||
75 	    si->mmio_base_high != upper_32_bits(mem))
76 		return 0;
77 
78 	/*
79 	 * acpi_gsi_to_irq() can't be used because some platforms do not save
80 	 * registered IRQs in the MP table. Instead we just try to register
81 	 * the GSI, which is the core part of the above mentioned function.
82 	 */
83 	ret = acpi_register_gsi(NULL, si->gsi_interrupt, si->interrupt_mode, si->interrupt_polarity);
84 	if (ret < 0)
85 		return 0;
86 
87 	/* Match device by Linux vIRQ */
88 	if (ret != irq)
89 		return 0;
90 
91 	dev_dbg(&adev->dev, "matches with %.4s%04X (rev %u)\n",
92 		(char *)&grp->vendor_id, grp->device_id, grp->revision);
93 
94 	/* Check if the request line range is available */
95 	if (si->base_request_line == 0 && si->num_handshake_signals == 0)
96 		return 0;
97 
98 	/* Set up DMA mask based on value from CSRT */
99 	ret = dma_coerce_mask_and_coherent(&adev->dev,
100 					   DMA_BIT_MASK(si->dma_address_width));
101 	if (ret)
102 		return 0;
103 
104 	adma->base_request_line = si->base_request_line;
105 	adma->end_request_line = si->base_request_line +
106 				 si->num_handshake_signals - 1;
107 
108 	dev_dbg(&adev->dev, "request line base: 0x%04x end: 0x%04x\n",
109 		adma->base_request_line, adma->end_request_line);
110 
111 	return 1;
112 }
113 
114 /**
115  * acpi_dma_parse_csrt - parse CSRT to exctract additional DMA resources
116  * @adev:	ACPI device to match with
117  * @adma:	struct acpi_dma of the given DMA controller
118  *
119  * CSRT or Core System Resources Table is a proprietary ACPI table
120  * introduced by Microsoft. This table can contain devices that are not in
121  * the system DSDT table. In particular DMA controllers might be described
122  * here.
123  *
124  * We are using this table to get the request line range of the specific DMA
125  * controller to be used later.
126  */
acpi_dma_parse_csrt(struct acpi_device * adev,struct acpi_dma * adma)127 static void acpi_dma_parse_csrt(struct acpi_device *adev, struct acpi_dma *adma)
128 {
129 	struct acpi_csrt_group *grp, *end;
130 	struct acpi_table_csrt *csrt;
131 	acpi_status status;
132 	int ret;
133 
134 	status = acpi_get_table(ACPI_SIG_CSRT, 0,
135 				(struct acpi_table_header **)&csrt);
136 	if (ACPI_FAILURE(status)) {
137 		if (status != AE_NOT_FOUND)
138 			dev_warn(&adev->dev, "failed to get the CSRT table\n");
139 		return;
140 	}
141 
142 	grp = (struct acpi_csrt_group *)(csrt + 1);
143 	end = (struct acpi_csrt_group *)((void *)csrt + csrt->header.length);
144 
145 	while (grp < end) {
146 		ret = acpi_dma_parse_resource_group(grp, adev, adma);
147 		if (ret < 0) {
148 			dev_warn(&adev->dev,
149 				 "error in parsing resource group\n");
150 			break;
151 		}
152 
153 		grp = (struct acpi_csrt_group *)((void *)grp + grp->length);
154 	}
155 
156 	acpi_put_table((struct acpi_table_header *)csrt);
157 }
158 
159 /**
160  * acpi_dma_controller_register - Register a DMA controller to ACPI DMA helpers
161  * @dev:		struct device of DMA controller
162  * @acpi_dma_xlate:	translation function which converts a dma specifier
163  *			into a dma_chan structure
164  * @data:		pointer to controller specific data to be used by
165  *			translation function
166  *
167  * Allocated memory should be freed with appropriate acpi_dma_controller_free()
168  * call.
169  *
170  * Return:
171  * 0 on success or appropriate errno value on error.
172  */
acpi_dma_controller_register(struct device * dev,struct dma_chan * (* acpi_dma_xlate)(struct acpi_dma_spec *,struct acpi_dma *),void * data)173 int acpi_dma_controller_register(struct device *dev,
174 		struct dma_chan *(*acpi_dma_xlate)
175 		(struct acpi_dma_spec *, struct acpi_dma *),
176 		void *data)
177 {
178 	struct acpi_device *adev;
179 	struct acpi_dma	*adma;
180 
181 	if (!dev || !acpi_dma_xlate)
182 		return -EINVAL;
183 
184 	/* Check if the device was enumerated by ACPI */
185 	adev = ACPI_COMPANION(dev);
186 	if (!adev)
187 		return -EINVAL;
188 
189 	adma = kzalloc(sizeof(*adma), GFP_KERNEL);
190 	if (!adma)
191 		return -ENOMEM;
192 
193 	adma->dev = dev;
194 	adma->acpi_dma_xlate = acpi_dma_xlate;
195 	adma->data = data;
196 
197 	acpi_dma_parse_csrt(adev, adma);
198 
199 	/* Now queue acpi_dma controller structure in list */
200 	mutex_lock(&acpi_dma_lock);
201 	list_add_tail(&adma->dma_controllers, &acpi_dma_list);
202 	mutex_unlock(&acpi_dma_lock);
203 
204 	return 0;
205 }
206 EXPORT_SYMBOL_GPL(acpi_dma_controller_register);
207 
208 /**
209  * acpi_dma_controller_free - Remove a DMA controller from ACPI DMA helpers list
210  * @dev:	struct device of DMA controller
211  *
212  * Memory allocated by acpi_dma_controller_register() is freed here.
213  *
214  * Return:
215  * 0 on success or appropriate errno value on error.
216  */
acpi_dma_controller_free(struct device * dev)217 int acpi_dma_controller_free(struct device *dev)
218 {
219 	struct acpi_dma *adma;
220 
221 	if (!dev)
222 		return -EINVAL;
223 
224 	mutex_lock(&acpi_dma_lock);
225 
226 	list_for_each_entry(adma, &acpi_dma_list, dma_controllers)
227 		if (adma->dev == dev) {
228 			list_del(&adma->dma_controllers);
229 			mutex_unlock(&acpi_dma_lock);
230 			kfree(adma);
231 			return 0;
232 		}
233 
234 	mutex_unlock(&acpi_dma_lock);
235 	return -ENODEV;
236 }
237 EXPORT_SYMBOL_GPL(acpi_dma_controller_free);
238 
devm_acpi_dma_release(struct device * dev,void * res)239 static void devm_acpi_dma_release(struct device *dev, void *res)
240 {
241 	acpi_dma_controller_free(dev);
242 }
243 
244 /**
245  * devm_acpi_dma_controller_register - resource managed acpi_dma_controller_register()
246  * @dev:		device that is registering this DMA controller
247  * @acpi_dma_xlate:	translation function
248  * @data:		pointer to controller specific data
249  *
250  * Managed acpi_dma_controller_register(). DMA controller registered by this
251  * function are automatically freed on driver detach. See
252  * acpi_dma_controller_register() for more information.
253  *
254  * Return:
255  * 0 on success or appropriate errno value on error.
256  */
devm_acpi_dma_controller_register(struct device * dev,struct dma_chan * (* acpi_dma_xlate)(struct acpi_dma_spec *,struct acpi_dma *),void * data)257 int devm_acpi_dma_controller_register(struct device *dev,
258 		struct dma_chan *(*acpi_dma_xlate)
259 		(struct acpi_dma_spec *, struct acpi_dma *),
260 		void *data)
261 {
262 	void *res;
263 	int ret;
264 
265 	res = devres_alloc(devm_acpi_dma_release, 0, GFP_KERNEL);
266 	if (!res)
267 		return -ENOMEM;
268 
269 	ret = acpi_dma_controller_register(dev, acpi_dma_xlate, data);
270 	if (ret) {
271 		devres_free(res);
272 		return ret;
273 	}
274 	devres_add(dev, res);
275 	return 0;
276 }
277 EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_register);
278 
279 /**
280  * devm_acpi_dma_controller_free - resource managed acpi_dma_controller_free()
281  * @dev:	device that is unregistering as DMA controller
282  *
283  * Unregister a DMA controller registered with
284  * devm_acpi_dma_controller_register(). Normally this function will not need to
285  * be called and the resource management code will ensure that the resource is
286  * freed.
287  */
devm_acpi_dma_controller_free(struct device * dev)288 void devm_acpi_dma_controller_free(struct device *dev)
289 {
290 	WARN_ON(devres_release(dev, devm_acpi_dma_release, NULL, NULL));
291 }
292 EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_free);
293 
294 /**
295  * acpi_dma_update_dma_spec - prepare dma specifier to pass to translation function
296  * @adma:	struct acpi_dma of DMA controller
297  * @dma_spec:	dma specifier to update
298  *
299  * Accordingly to ACPI 5.0 Specification Table 6-170 "Fixed DMA Resource
300  * Descriptor":
301  *	DMA Request Line bits is a platform-relative number uniquely
302  *	identifying the request line assigned. Request line-to-Controller
303  *	mapping is done in a controller-specific OS driver.
304  * That's why we can safely adjust slave_id when the appropriate controller is
305  * found.
306  *
307  * Return:
308  * 0, if no information is avaiable, -1 on mismatch, and 1 otherwise.
309  */
acpi_dma_update_dma_spec(struct acpi_dma * adma,struct acpi_dma_spec * dma_spec)310 static int acpi_dma_update_dma_spec(struct acpi_dma *adma,
311 		struct acpi_dma_spec *dma_spec)
312 {
313 	/* Set link to the DMA controller device */
314 	dma_spec->dev = adma->dev;
315 
316 	/* Check if the request line range is available */
317 	if (adma->base_request_line == 0 && adma->end_request_line == 0)
318 		return 0;
319 
320 	/* Check if slave_id falls to the range */
321 	if (dma_spec->slave_id < adma->base_request_line ||
322 	    dma_spec->slave_id > adma->end_request_line)
323 		return -1;
324 
325 	/*
326 	 * Here we adjust slave_id. It should be a relative number to the base
327 	 * request line.
328 	 */
329 	dma_spec->slave_id -= adma->base_request_line;
330 
331 	return 1;
332 }
333 
334 struct acpi_dma_parser_data {
335 	struct acpi_dma_spec dma_spec;
336 	size_t index;
337 	size_t n;
338 };
339 
340 /**
341  * acpi_dma_parse_fixed_dma - Parse FixedDMA ACPI resources to a DMA specifier
342  * @res:	struct acpi_resource to get FixedDMA resources from
343  * @data:	pointer to a helper struct acpi_dma_parser_data
344  */
acpi_dma_parse_fixed_dma(struct acpi_resource * res,void * data)345 static int acpi_dma_parse_fixed_dma(struct acpi_resource *res, void *data)
346 {
347 	struct acpi_dma_parser_data *pdata = data;
348 
349 	if (res->type == ACPI_RESOURCE_TYPE_FIXED_DMA) {
350 		struct acpi_resource_fixed_dma *dma = &res->data.fixed_dma;
351 
352 		if (pdata->n++ == pdata->index) {
353 			pdata->dma_spec.chan_id = dma->channels;
354 			pdata->dma_spec.slave_id = dma->request_lines;
355 		}
356 	}
357 
358 	/* Tell the ACPI core to skip this resource */
359 	return 1;
360 }
361 
362 /**
363  * acpi_dma_request_slave_chan_by_index - Get the DMA slave channel
364  * @dev:	struct device to get DMA request from
365  * @index:	index of FixedDMA descriptor for @dev
366  *
367  * Return:
368  * Pointer to appropriate dma channel on success or an error pointer.
369  */
acpi_dma_request_slave_chan_by_index(struct device * dev,size_t index)370 struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev,
371 		size_t index)
372 {
373 	struct acpi_dma_parser_data pdata;
374 	struct acpi_dma_spec *dma_spec = &pdata.dma_spec;
375 	struct acpi_device *adev = ACPI_COMPANION(dev);
376 	struct list_head resource_list;
377 	struct acpi_dma *adma;
378 	struct dma_chan *chan = NULL;
379 	int found;
380 	int ret;
381 
382 	memset(&pdata, 0, sizeof(pdata));
383 	pdata.index = index;
384 
385 	/* Initial values for the request line and channel */
386 	dma_spec->chan_id = -1;
387 	dma_spec->slave_id = -1;
388 
389 	INIT_LIST_HEAD(&resource_list);
390 	ret = acpi_dev_get_resources(adev, &resource_list,
391 				     acpi_dma_parse_fixed_dma, &pdata);
392 	acpi_dev_free_resource_list(&resource_list);
393 	if (ret < 0)
394 		return ERR_PTR(ret);
395 
396 	if (dma_spec->slave_id < 0 || dma_spec->chan_id < 0)
397 		return ERR_PTR(-ENODEV);
398 
399 	mutex_lock(&acpi_dma_lock);
400 
401 	list_for_each_entry(adma, &acpi_dma_list, dma_controllers) {
402 		/*
403 		 * We are not going to call translation function if slave_id
404 		 * doesn't fall to the request range.
405 		 */
406 		found = acpi_dma_update_dma_spec(adma, dma_spec);
407 		if (found < 0)
408 			continue;
409 		chan = adma->acpi_dma_xlate(dma_spec, adma);
410 		/*
411 		 * Try to get a channel only from the DMA controller that
412 		 * matches the slave_id. See acpi_dma_update_dma_spec()
413 		 * description for the details.
414 		 */
415 		if (found > 0 || chan)
416 			break;
417 	}
418 
419 	mutex_unlock(&acpi_dma_lock);
420 	return chan ? chan : ERR_PTR(-EPROBE_DEFER);
421 }
422 EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_index);
423 
424 /**
425  * acpi_dma_request_slave_chan_by_name - Get the DMA slave channel
426  * @dev:	struct device to get DMA request from
427  * @name:	represents corresponding FixedDMA descriptor for @dev
428  *
429  * In order to support both Device Tree and ACPI in a single driver we
430  * translate the names "tx" and "rx" here based on the most common case where
431  * the first FixedDMA descriptor is TX and second is RX.
432  *
433  * If the device has "dma-names" property the FixedDMA descriptor indices
434  * are retrieved based on those. Otherwise the function falls back using
435  * hardcoded indices.
436  *
437  * Return:
438  * Pointer to appropriate dma channel on success or an error pointer.
439  */
acpi_dma_request_slave_chan_by_name(struct device * dev,const char * name)440 struct dma_chan *acpi_dma_request_slave_chan_by_name(struct device *dev,
441 		const char *name)
442 {
443 	int index;
444 
445 	index = device_property_match_string(dev, "dma-names", name);
446 	if (index < 0) {
447 		if (!strcmp(name, "tx"))
448 			index = 0;
449 		else if (!strcmp(name, "rx"))
450 			index = 1;
451 		else
452 			return ERR_PTR(-ENODEV);
453 	}
454 
455 	dev_dbg(dev, "Looking for DMA channel \"%s\" at index %d...\n", name, index);
456 	return acpi_dma_request_slave_chan_by_index(dev, index);
457 }
458 EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_name);
459 
460 /**
461  * acpi_dma_simple_xlate - Simple ACPI DMA engine translation helper
462  * @dma_spec: pointer to ACPI DMA specifier
463  * @adma: pointer to ACPI DMA controller data
464  *
465  * A simple translation function for ACPI based devices. Passes &struct
466  * dma_spec to the DMA controller driver provided filter function.
467  *
468  * Return:
469  * Pointer to the channel if found or %NULL otherwise.
470  */
acpi_dma_simple_xlate(struct acpi_dma_spec * dma_spec,struct acpi_dma * adma)471 struct dma_chan *acpi_dma_simple_xlate(struct acpi_dma_spec *dma_spec,
472 		struct acpi_dma *adma)
473 {
474 	struct acpi_dma_filter_info *info = adma->data;
475 
476 	if (!info || !info->filter_fn)
477 		return NULL;
478 
479 	return dma_request_channel(info->dma_cap, info->filter_fn, dma_spec);
480 }
481 EXPORT_SYMBOL_GPL(acpi_dma_simple_xlate);
482