2 * ACPI helpers for DMA request / controller
6 * Copyright (C) 2013, Intel Corporation
7 * Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
8 * Mika Westerberg <mika.westerberg@linux.intel.com>
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.
15 #include <linux/device.h>
16 #include <linux/err.h>
17 #include <linux/module.h>
18 #include <linux/list.h>
19 #include <linux/mutex.h>
20 #include <linux/slab.h>
21 #include <linux/ioport.h>
22 #include <linux/acpi.h>
23 #include <linux/acpi_dma.h>
25 static LIST_HEAD(acpi_dma_list);
26 static DEFINE_MUTEX(acpi_dma_lock);
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
34 * In order to match a device from DSDT table to the corresponding CSRT device
35 * we use MMIO address and IRQ.
38 * 1 on success, 0 when no information is available, or appropriate errno value
41 static int acpi_dma_parse_resource_group(const struct acpi_csrt_group *grp,
42 struct acpi_device *adev, struct acpi_dma *adma)
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;
50 if (grp->shared_info_length != sizeof(struct acpi_csrt_shared_info))
53 INIT_LIST_HEAD(&resource_list);
54 ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
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;
65 acpi_dev_free_resource_list(&resource_list);
67 /* Consider initial zero values as resource not found */
68 if (mem == 0 && irq == 0)
71 si = (const struct acpi_csrt_shared_info *)&grp[1];
73 /* Match device by MMIO and IRQ */
74 if (si->mmio_base_low != mem || si->gsi_interrupt != irq)
77 dev_dbg(&adev->dev, "matches with %.4s%04X (rev %u)\n",
78 (char *)&grp->vendor_id, grp->device_id, grp->revision);
80 /* Check if the request line range is available */
81 if (si->base_request_line == 0 && si->num_handshake_signals == 0)
84 adma->base_request_line = si->base_request_line;
85 adma->end_request_line = si->base_request_line +
86 si->num_handshake_signals - 1;
88 dev_dbg(&adev->dev, "request line base: 0x%04x end: 0x%04x\n",
89 adma->base_request_line, adma->end_request_line);
95 * acpi_dma_parse_csrt - parse CSRT to exctract additional DMA resources
96 * @adev: ACPI device to match with
97 * @adma: struct acpi_dma of the given DMA controller
99 * CSRT or Core System Resources Table is a proprietary ACPI table
100 * introduced by Microsoft. This table can contain devices that are not in
101 * the system DSDT table. In particular DMA controllers might be described
104 * We are using this table to get the request line range of the specific DMA
105 * controller to be used later.
107 static void acpi_dma_parse_csrt(struct acpi_device *adev, struct acpi_dma *adma)
109 struct acpi_csrt_group *grp, *end;
110 struct acpi_table_csrt *csrt;
114 status = acpi_get_table(ACPI_SIG_CSRT, 0,
115 (struct acpi_table_header **)&csrt);
116 if (ACPI_FAILURE(status)) {
117 if (status != AE_NOT_FOUND)
118 dev_warn(&adev->dev, "failed to get the CSRT table\n");
122 grp = (struct acpi_csrt_group *)(csrt + 1);
123 end = (struct acpi_csrt_group *)((void *)csrt + csrt->header.length);
126 ret = acpi_dma_parse_resource_group(grp, adev, adma);
129 "error in parsing resource group\n");
133 grp = (struct acpi_csrt_group *)((void *)grp + grp->length);
138 * acpi_dma_controller_register - Register a DMA controller to ACPI DMA helpers
139 * @dev: struct device of DMA controller
140 * @acpi_dma_xlate: translation function which converts a dma specifier
141 * into a dma_chan structure
142 * @data pointer to controller specific data to be used by
143 * translation function
145 * Allocated memory should be freed with appropriate acpi_dma_controller_free()
149 * 0 on success or appropriate errno value on error.
151 int acpi_dma_controller_register(struct device *dev,
152 struct dma_chan *(*acpi_dma_xlate)
153 (struct acpi_dma_spec *, struct acpi_dma *),
156 struct acpi_device *adev;
157 struct acpi_dma *adma;
159 if (!dev || !acpi_dma_xlate)
162 /* Check if the device was enumerated by ACPI */
163 adev = ACPI_COMPANION(dev);
167 adma = kzalloc(sizeof(*adma), GFP_KERNEL);
172 adma->acpi_dma_xlate = acpi_dma_xlate;
175 acpi_dma_parse_csrt(adev, adma);
177 /* 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);
184 EXPORT_SYMBOL_GPL(acpi_dma_controller_register);
187 * acpi_dma_controller_free - Remove a DMA controller from ACPI DMA helpers list
188 * @dev: struct device of DMA controller
190 * Memory allocated by acpi_dma_controller_register() is freed here.
193 * 0 on success or appropriate errno value on error.
195 int acpi_dma_controller_free(struct device *dev)
197 struct acpi_dma *adma;
202 mutex_lock(&acpi_dma_lock);
204 list_for_each_entry(adma, &acpi_dma_list, dma_controllers)
205 if (adma->dev == dev) {
206 list_del(&adma->dma_controllers);
207 mutex_unlock(&acpi_dma_lock);
212 mutex_unlock(&acpi_dma_lock);
215 EXPORT_SYMBOL_GPL(acpi_dma_controller_free);
217 static void devm_acpi_dma_release(struct device *dev, void *res)
219 acpi_dma_controller_free(dev);
223 * devm_acpi_dma_controller_register - resource managed acpi_dma_controller_register()
224 * @dev: device that is registering this DMA controller
225 * @acpi_dma_xlate: translation function
226 * @data pointer to controller specific data
228 * Managed acpi_dma_controller_register(). DMA controller registered by this
229 * function are automatically freed on driver detach. See
230 * acpi_dma_controller_register() for more information.
233 * 0 on success or appropriate errno value on error.
235 int devm_acpi_dma_controller_register(struct device *dev,
236 struct dma_chan *(*acpi_dma_xlate)
237 (struct acpi_dma_spec *, struct acpi_dma *),
243 res = devres_alloc(devm_acpi_dma_release, 0, GFP_KERNEL);
247 ret = acpi_dma_controller_register(dev, acpi_dma_xlate, data);
252 devres_add(dev, res);
255 EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_register);
258 * devm_acpi_dma_controller_free - resource managed acpi_dma_controller_free()
260 * Unregister a DMA controller registered with
261 * devm_acpi_dma_controller_register(). Normally this function will not need to
262 * be called and the resource management code will ensure that the resource is
265 void devm_acpi_dma_controller_free(struct device *dev)
267 WARN_ON(devres_release(dev, devm_acpi_dma_release, NULL, NULL));
269 EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_free);
272 * acpi_dma_update_dma_spec - prepare dma specifier to pass to translation function
273 * @adma: struct acpi_dma of DMA controller
274 * @dma_spec: dma specifier to update
276 * Accordingly to ACPI 5.0 Specification Table 6-170 "Fixed DMA Resource
278 * DMA Request Line bits is a platform-relative number uniquely
279 * identifying the request line assigned. Request line-to-Controller
280 * mapping is done in a controller-specific OS driver.
281 * That's why we can safely adjust slave_id when the appropriate controller is
285 * 0, if no information is avaiable, -1 on mismatch, and 1 otherwise.
287 static int acpi_dma_update_dma_spec(struct acpi_dma *adma,
288 struct acpi_dma_spec *dma_spec)
290 /* Set link to the DMA controller device */
291 dma_spec->dev = adma->dev;
293 /* Check if the request line range is available */
294 if (adma->base_request_line == 0 && adma->end_request_line == 0)
297 /* Check if slave_id falls to the range */
298 if (dma_spec->slave_id < adma->base_request_line ||
299 dma_spec->slave_id > adma->end_request_line)
303 * Here we adjust slave_id. It should be a relative number to the base
306 dma_spec->slave_id -= adma->base_request_line;
311 struct acpi_dma_parser_data {
312 struct acpi_dma_spec dma_spec;
318 * acpi_dma_parse_fixed_dma - Parse FixedDMA ACPI resources to a DMA specifier
319 * @res: struct acpi_resource to get FixedDMA resources from
320 * @data: pointer to a helper struct acpi_dma_parser_data
322 static int acpi_dma_parse_fixed_dma(struct acpi_resource *res, void *data)
324 struct acpi_dma_parser_data *pdata = data;
326 if (res->type == ACPI_RESOURCE_TYPE_FIXED_DMA) {
327 struct acpi_resource_fixed_dma *dma = &res->data.fixed_dma;
329 if (pdata->n++ == pdata->index) {
330 pdata->dma_spec.chan_id = dma->channels;
331 pdata->dma_spec.slave_id = dma->request_lines;
335 /* Tell the ACPI core to skip this resource */
340 * acpi_dma_request_slave_chan_by_index - Get the DMA slave channel
341 * @dev: struct device to get DMA request from
342 * @index: index of FixedDMA descriptor for @dev
345 * Pointer to appropriate dma channel on success or an error pointer.
347 struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev,
350 struct acpi_dma_parser_data pdata;
351 struct acpi_dma_spec *dma_spec = &pdata.dma_spec;
352 struct list_head resource_list;
353 struct acpi_device *adev;
354 struct acpi_dma *adma;
355 struct dma_chan *chan = NULL;
358 /* Check if the device was enumerated by ACPI */
360 return ERR_PTR(-ENODEV);
362 adev = ACPI_COMPANION(dev);
364 return ERR_PTR(-ENODEV);
366 memset(&pdata, 0, sizeof(pdata));
369 /* Initial values for the request line and channel */
370 dma_spec->chan_id = -1;
371 dma_spec->slave_id = -1;
373 INIT_LIST_HEAD(&resource_list);
374 acpi_dev_get_resources(adev, &resource_list,
375 acpi_dma_parse_fixed_dma, &pdata);
376 acpi_dev_free_resource_list(&resource_list);
378 if (dma_spec->slave_id < 0 || dma_spec->chan_id < 0)
379 return ERR_PTR(-ENODEV);
381 mutex_lock(&acpi_dma_lock);
383 list_for_each_entry(adma, &acpi_dma_list, dma_controllers) {
385 * We are not going to call translation function if slave_id
386 * doesn't fall to the request range.
388 found = acpi_dma_update_dma_spec(adma, dma_spec);
391 chan = adma->acpi_dma_xlate(dma_spec, adma);
393 * Try to get a channel only from the DMA controller that
394 * matches the slave_id. See acpi_dma_update_dma_spec()
395 * description for the details.
397 if (found > 0 || chan)
401 mutex_unlock(&acpi_dma_lock);
402 return chan ? chan : ERR_PTR(-EPROBE_DEFER);
404 EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_index);
407 * acpi_dma_request_slave_chan_by_name - Get the DMA slave channel
408 * @dev: struct device to get DMA request from
409 * @name: represents corresponding FixedDMA descriptor for @dev
411 * In order to support both Device Tree and ACPI in a single driver we
412 * translate the names "tx" and "rx" here based on the most common case where
413 * the first FixedDMA descriptor is TX and second is RX.
416 * Pointer to appropriate dma channel on success or an error pointer.
418 struct dma_chan *acpi_dma_request_slave_chan_by_name(struct device *dev,
423 if (!strcmp(name, "tx"))
425 else if (!strcmp(name, "rx"))
428 return ERR_PTR(-ENODEV);
430 return acpi_dma_request_slave_chan_by_index(dev, index);
432 EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_name);
435 * acpi_dma_simple_xlate - Simple ACPI DMA engine translation helper
436 * @dma_spec: pointer to ACPI DMA specifier
437 * @adma: pointer to ACPI DMA controller data
439 * A simple translation function for ACPI based devices. Passes &struct
440 * dma_spec to the DMA controller driver provided filter function.
443 * Pointer to the channel if found or %NULL otherwise.
445 struct dma_chan *acpi_dma_simple_xlate(struct acpi_dma_spec *dma_spec,
446 struct acpi_dma *adma)
448 struct acpi_dma_filter_info *info = adma->data;
450 if (!info || !info->filter_fn)
453 return dma_request_channel(info->dma_cap, info->filter_fn, dma_spec);
455 EXPORT_SYMBOL_GPL(acpi_dma_simple_xlate);