1 files changed, 279 insertions, 0 deletions
diff --git a/drivers/dma/acpi-dma.c b/drivers/dma/acpi-dma.c
new file mode 100644
index 00000000000..ba6fc62e965
--- /dev/null
+++ b/drivers/dma/acpi-dma.c
@@ -0,0 +1,279 @@
+/*
+ * ACPI helpers for DMA request / controller
+ *
+ * Based on of-dma.c
+ *
+ * Copyright (C) 2013, Intel Corporation
+ * Author: Andy Shevchenko <andriy.shevchenko@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/acpi.h>
+#include <linux/acpi_dma.h>
+
+static LIST_HEAD(acpi_dma_list);
+static DEFINE_MUTEX(acpi_dma_lock);
+
+/**
+ * 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;
+
+	/* 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);
+
+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;
+
+	/* 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) {
+		dma_spec->dev = adma->dev;
+		chan = adma->acpi_dma_xlate(dma_spec, adma);
+		if (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);