[deliverable/linux.git] / drivers / dma / acpi-dma.c

/*
 * ACPI helpers for DMA request / controller
 *
 * Based on of-dma.c
 *
 * Copyright (C) 2013, Intel Corporation
 * Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
 *	    Mika Westerberg <mika.westerberg@linux.intel.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/device.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/acpi.h>
#include <linux/acpi_dma.h>

static LIST_HEAD(acpi_dma_list);
static DEFINE_MUTEX(acpi_dma_lock);

/**
 * acpi_dma_parse_resource_group - match device and parse resource group
 * @grp:	CSRT resource group
 * @adev:	ACPI device to match with
 * @adma:	struct acpi_dma of the given DMA controller
 *
 * Returns 1 on success, 0 when no information is available, or appropriate
 * errno value on error.
 *
 * In order to match a device from DSDT table to the corresponding CSRT device
 * we use MMIO address and IRQ.
 */
static int acpi_dma_parse_resource_group(const struct acpi_csrt_group *grp,
		struct acpi_device *adev, struct acpi_dma *adma)
{
	const struct acpi_csrt_shared_info *si;
	struct list_head resource_list;
	struct resource_list_entry *rentry;
	resource_size_t mem = 0, irq = 0;
	int ret;

	if (grp->shared_info_length != sizeof(struct acpi_csrt_shared_info))
		return -ENODEV;

	INIT_LIST_HEAD(&resource_list);
	ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
	if (ret <= 0)
		return 0;

	list_for_each_entry(rentry, &resource_list, node) {
		if (resource_type(&rentry->res) == IORESOURCE_MEM)
			mem = rentry->res.start;
		else if (resource_type(&rentry->res) == IORESOURCE_IRQ)
			irq = rentry->res.start;
	}

	acpi_dev_free_resource_list(&resource_list);

	/* Consider initial zero values as resource not found */
	if (mem == 0 && irq == 0)
		return 0;

	si = (const struct acpi_csrt_shared_info *)&grp[1];

	/* Match device by MMIO and IRQ */
	if (si->mmio_base_low != mem || si->gsi_interrupt != irq)
		return 0;

	dev_dbg(&adev->dev, "matches with %.4s%04X (rev %u)\n",
		(char *)&grp->vendor_id, grp->device_id, grp->revision);

	/* Check if the request line range is available */
	if (si->base_request_line == 0 && si->num_handshake_signals == 0)
		return 0;

	adma->base_request_line = si->base_request_line;
	adma->end_request_line = si->base_request_line +
				 si->num_handshake_signals - 1;

	dev_dbg(&adev->dev, "request line base: 0x%04x end: 0x%04x\n",
		adma->base_request_line, adma->end_request_line);

	return 1;
}

/**
 * acpi_dma_parse_csrt - parse CSRT to exctract additional DMA resources
 * @adev:	ACPI device to match with
 * @adma:	struct acpi_dma of the given DMA controller
 *
 * CSRT or Core System Resources Table is a proprietary ACPI table
 * introduced by Microsoft. This table can contain devices that are not in
 * the system DSDT table. In particular DMA controllers might be described
 * here.
 *
 * We are using this table to get the request line range of the specific DMA
 * controller to be used later.
 *
 */
static void acpi_dma_parse_csrt(struct acpi_device *adev, struct acpi_dma *adma)
{
	struct acpi_csrt_group *grp, *end;
	struct acpi_table_csrt *csrt;
	acpi_status status;
	int ret;

	status = acpi_get_table(ACPI_SIG_CSRT, 0,
				(struct acpi_table_header **)&csrt);
	if (ACPI_FAILURE(status)) {
		if (status != AE_NOT_FOUND)
			dev_warn(&adev->dev, "failed to get the CSRT table\n");
		return;
	}

	grp = (struct acpi_csrt_group *)(csrt + 1);
	end = (struct acpi_csrt_group *)((void *)csrt + csrt->header.length);

	while (grp < end) {
		ret = acpi_dma_parse_resource_group(grp, adev, adma);
		if (ret < 0) {
			dev_warn(&adev->dev,
				 "error in parsing resource group\n");
			return;
		}

		grp = (struct acpi_csrt_group *)((void *)grp + grp->length);
	}
}

/**
 * acpi_dma_controller_register - Register a DMA controller to ACPI DMA helpers
 * @dev:		struct device of DMA controller
 * @acpi_dma_xlate:	translation function which converts a dma specifier
 *			into a dma_chan structure
 * @data		pointer to controller specific data to be used by
 *			translation function
 *
 * Returns 0 on success or appropriate errno value on error.
 *
 * Allocated memory should be freed with appropriate acpi_dma_controller_free()
 * call.
 */
int acpi_dma_controller_register(struct device *dev,
		struct dma_chan *(*acpi_dma_xlate)
		(struct acpi_dma_spec *, struct acpi_dma *),
		void *data)
{
	struct acpi_device *adev;
	struct acpi_dma	*adma;

	if (!dev || !acpi_dma_xlate)
		return -EINVAL;

	/* Check if the device was enumerated by ACPI */
	if (!ACPI_HANDLE(dev))
		return -EINVAL;

	if (acpi_bus_get_device(ACPI_HANDLE(dev), &adev))
		return -EINVAL;

	adma = kzalloc(sizeof(*adma), GFP_KERNEL);
	if (!adma)
		return -ENOMEM;

	adma->dev = dev;
	adma->acpi_dma_xlate = acpi_dma_xlate;
	adma->data = data;

	acpi_dma_parse_csrt(adev, adma);

	/* Now queue acpi_dma controller structure in list */
	mutex_lock(&acpi_dma_lock);
	list_add_tail(&adma->dma_controllers, &acpi_dma_list);
	mutex_unlock(&acpi_dma_lock);

	return 0;
}
EXPORT_SYMBOL_GPL(acpi_dma_controller_register);

/**
 * acpi_dma_controller_free - Remove a DMA controller from ACPI DMA helpers list
 * @dev:	struct device of DMA controller
 *
 * Memory allocated by acpi_dma_controller_register() is freed here.
 */
int acpi_dma_controller_free(struct device *dev)
{
	struct acpi_dma *adma;

	if (!dev)
		return -EINVAL;

	mutex_lock(&acpi_dma_lock);

	list_for_each_entry(adma, &acpi_dma_list, dma_controllers)
		if (adma->dev == dev) {
			list_del(&adma->dma_controllers);
			mutex_unlock(&acpi_dma_lock);
			kfree(adma);
			return 0;
		}

	mutex_unlock(&acpi_dma_lock);
	return -ENODEV;
}
EXPORT_SYMBOL_GPL(acpi_dma_controller_free);

static void devm_acpi_dma_release(struct device *dev, void *res)
{
	acpi_dma_controller_free(dev);
}

/**
 * devm_acpi_dma_controller_register - resource managed acpi_dma_controller_register()
 * @dev:		device that is registering this DMA controller
 * @acpi_dma_xlate:	translation function
 * @data		pointer to controller specific data
 *
 * Managed acpi_dma_controller_register(). DMA controller registered by this
 * function are automatically freed on driver detach. See
 * acpi_dma_controller_register() for more information.
 */
int devm_acpi_dma_controller_register(struct device *dev,
		struct dma_chan *(*acpi_dma_xlate)
		(struct acpi_dma_spec *, struct acpi_dma *),
		void *data)
{
	void *res;
	int ret;

	res = devres_alloc(devm_acpi_dma_release, 0, GFP_KERNEL);
	if (!res)
		return -ENOMEM;

	ret = acpi_dma_controller_register(dev, acpi_dma_xlate, data);
	if (ret) {
		devres_free(res);
		return ret;
	}
	devres_add(dev, res);
	return 0;
}
EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_register);

/**
 * devm_acpi_dma_controller_free - resource managed acpi_dma_controller_free()
 *
 * Unregister a DMA controller registered with
 * devm_acpi_dma_controller_register(). Normally this function will not need to
 * be called and the resource management code will ensure that the resource is
 * freed.
 */
void devm_acpi_dma_controller_free(struct device *dev)
{
	WARN_ON(devres_destroy(dev, devm_acpi_dma_release, NULL, NULL));
}
EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_free);

/**
 * acpi_dma_update_dma_spec - prepare dma specifier to pass to translation function
 * @adma:	struct acpi_dma of DMA controller
 * @dma_spec:	dma specifier to update
 *
 * Returns 0, if no information is avaiable, -1 on mismatch, and 1 otherwise.
 *
 * Accordingly to ACPI 5.0 Specification Table 6-170 "Fixed DMA Resource
 * Descriptor":
 *	DMA Request Line bits is a platform-relative number uniquely
 *	identifying the request line assigned. Request line-to-Controller
 *	mapping is done in a controller-specific OS driver.
 * That's why we can safely adjust slave_id when the appropriate controller is
 * found.
 */
static int acpi_dma_update_dma_spec(struct acpi_dma *adma,
		struct acpi_dma_spec *dma_spec)
{
	/* Set link to the DMA controller device */
	dma_spec->dev = adma->dev;

	/* Check if the request line range is available */
	if (adma->base_request_line == 0 && adma->end_request_line == 0)
		return 0;

	/* Check if slave_id falls to the range */
	if (dma_spec->slave_id < adma->base_request_line ||
	    dma_spec->slave_id > adma->end_request_line)
		return -1;

	/*
	 * Here we adjust slave_id. It should be a relative number to the base
	 * request line.
	 */
	dma_spec->slave_id -= adma->base_request_line;

	return 1;
}

struct acpi_dma_parser_data {
	struct acpi_dma_spec dma_spec;
	size_t index;
	size_t n;
};

/**
 * acpi_dma_parse_fixed_dma - Parse FixedDMA ACPI resources to a DMA specifier
 * @res:	struct acpi_resource to get FixedDMA resources from
 * @data:	pointer to a helper struct acpi_dma_parser_data
 */
static int acpi_dma_parse_fixed_dma(struct acpi_resource *res, void *data)
{
	struct acpi_dma_parser_data *pdata = data;

	if (res->type == ACPI_RESOURCE_TYPE_FIXED_DMA) {
		struct acpi_resource_fixed_dma *dma = &res->data.fixed_dma;

		if (pdata->n++ == pdata->index) {
			pdata->dma_spec.chan_id = dma->channels;
			pdata->dma_spec.slave_id = dma->request_lines;
		}
	}

	/* Tell the ACPI core to skip this resource */
	return 1;
}

/**
 * acpi_dma_request_slave_chan_by_index - Get the DMA slave channel
 * @dev:	struct device to get DMA request from
 * @index:	index of FixedDMA descriptor for @dev
 *
 * Returns pointer to appropriate dma channel on success or NULL on error.
 */
struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev,
		size_t index)
{
	struct acpi_dma_parser_data pdata;
	struct acpi_dma_spec *dma_spec = &pdata.dma_spec;
	struct list_head resource_list;
	struct acpi_device *adev;
	struct acpi_dma *adma;
	struct dma_chan *chan = NULL;
	int found;

	/* Check if the device was enumerated by ACPI */
	if (!dev || !ACPI_HANDLE(dev))
		return NULL;

	if (acpi_bus_get_device(ACPI_HANDLE(dev), &adev))
		return NULL;

	memset(&pdata, 0, sizeof(pdata));
	pdata.index = index;

	/* Initial values for the request line and channel */
	dma_spec->chan_id = -1;
	dma_spec->slave_id = -1;

	INIT_LIST_HEAD(&resource_list);
	acpi_dev_get_resources(adev, &resource_list,
			acpi_dma_parse_fixed_dma, &pdata);
	acpi_dev_free_resource_list(&resource_list);

	if (dma_spec->slave_id < 0 || dma_spec->chan_id < 0)
		return NULL;

	mutex_lock(&acpi_dma_lock);

	list_for_each_entry(adma, &acpi_dma_list, dma_controllers) {
		/*
		 * We are not going to call translation function if slave_id
		 * doesn't fall to the request range.
		 */
		found = acpi_dma_update_dma_spec(adma, dma_spec);
		if (found < 0)
			continue;
		chan = adma->acpi_dma_xlate(dma_spec, adma);
		/*
		 * Try to get a channel only from the DMA controller that
		 * matches the slave_id. See acpi_dma_update_dma_spec()
		 * description for the details.
		 */
		if (found > 0 || chan)
			break;
	}

	mutex_unlock(&acpi_dma_lock);
	return chan;
}
EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_index);

/**
 * acpi_dma_request_slave_chan_by_name - Get the DMA slave channel
 * @dev:	struct device to get DMA request from
 * @name:	represents corresponding FixedDMA descriptor for @dev
 *
 * In order to support both Device Tree and ACPI in a single driver we
 * translate the names "tx" and "rx" here based on the most common case where
 * the first FixedDMA descriptor is TX and second is RX.
 *
 * Returns pointer to appropriate dma channel on success or NULL on error.
 */
struct dma_chan *acpi_dma_request_slave_chan_by_name(struct device *dev,
		const char *name)
{
	size_t index;

	if (!strcmp(name, "tx"))
		index = 0;
	else if (!strcmp(name, "rx"))
		index = 1;
	else
		return NULL;

	return acpi_dma_request_slave_chan_by_index(dev, index);
}
EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_name);

/**
 * acpi_dma_simple_xlate - Simple ACPI DMA engine translation helper
 * @dma_spec: pointer to ACPI DMA specifier
 * @adma: pointer to ACPI DMA controller data
 *
 * A simple translation function for ACPI based devices. Passes &struct
 * dma_spec to the DMA controller driver provided filter function. Returns
 * pointer to the channel if found or %NULL otherwise.
 */
struct dma_chan *acpi_dma_simple_xlate(struct acpi_dma_spec *dma_spec,
		struct acpi_dma *adma)
{
	struct acpi_dma_filter_info *info = adma->data;

	if (!info || !info->filter_fn)
		return NULL;

	return dma_request_channel(info->dma_cap, info->filter_fn, dma_spec);
}
EXPORT_SYMBOL_GPL(acpi_dma_simple_xlate);
Commit	Line	Data
1b2e98bc AS	1	/*
	2	* ACPI helpers for DMA request / controller
	3	*
	4	* Based on of-dma.c
	5	*
	6	* Copyright (C) 2013, Intel Corporation
ee8209fd AS	7	* Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
ee8209fd AS	8	* Mika Westerberg <mika.westerberg@linux.intel.com>
1b2e98bc AS	9	*
	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>
ee8209fd	20	#include <linux/ioport.h>
1b2e98bc AS	21	#include <linux/acpi.h>
	22	#include <linux/acpi_dma.h>
	23
	24	static LIST_HEAD(acpi_dma_list);
	25	static DEFINE_MUTEX(acpi_dma_lock);
	26
ee8209fd AS	27	/**
	28	* 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	*/
	39	static 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;
ee8209fd AS	46	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
ee8209fd	75	dev_dbg(&adev->dev, "matches with %.4s%04X (rev %u)\n",
b4d6d336	76	(char *)&grp->vendor_id, grp->device_id, grp->revision);
ee8209fd AS	77
	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	*/
	106	static 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
1b2e98bc AS	136	/**
	137	* 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	*/
	149	int 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
ee8209fd AS	175	acpi_dma_parse_csrt(adev, adma);
ee8209fd AS	176
1b2e98bc AS	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);
	181
	182	return 0;
	183	}
	184	EXPORT_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	*/
	192	int 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	}
	212	EXPORT_SYMBOL_GPL(acpi_dma_controller_free);
	213
	214	static 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	*/
	229	int 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	}
249	EXPORT_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	*/
259	void devm_acpi_dma_controller_free(struct device *dev)
260	{
261	WARN_ON(devres_destroy(dev, devm_acpi_dma_release, NULL, NULL));
262	}
263	EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_free);
264
ee8209fd AS	265	/**
	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	*/
	280	static 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
1b2e98bc AS	304	struct 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	*/
	315	static 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	*/
	339	struct 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;
ee8209fd	348	int found;
1b2e98bc AS	349
	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) {
ee8209fd AS	375	/*
	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;
1b2e98bc	382	chan = adma->acpi_dma_xlate(dma_spec, adma);
ee8209fd AS	383	/*
	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)
1b2e98bc AS	389	break;
	390	}
	391
	392	mutex_unlock(&acpi_dma_lock);
	393	return chan;
	394	}
	395	EXPORT_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	*/
	408	struct 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	}
	422	EXPORT_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	*/
	433	struct 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	}
	443	EXPORT_SYMBOL_GPL(acpi_dma_simple_xlate);