1 files changed, 481 insertions, 0 deletions
diff --git a/drivers/dma/acpi-dma.c b/drivers/dma/acpi-dma.c
new file mode 100644
index 000000000..5906eae26
--- /dev/null
+++ b/drivers/dma/acpi-dma.c
@@ -0,0 +1,481 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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>
+ */
+
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/kernel.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>
+#include <linux/property.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
+ *
+ * In order to match a device from DSDT table to the corresponding CSRT device
+ * we use MMIO address and IRQ.
+ *
+ * Return:
+ * 1 on success, 0 when no information is available, or appropriate errno value
+ * on error.
+ */
+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_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 */
+	if (si->mmio_base_low != lower_32_bits(mem) ||
+	    si->mmio_base_high != upper_32_bits(mem))
+		return 0;
+
+	/*
+	 * acpi_gsi_to_irq() can't be used because some platforms do not save
+	 * registered IRQs in the MP table. Instead we just try to register
+	 * the GSI, which is the core part of the above mentioned function.
+	 */
+	ret = acpi_register_gsi(NULL, si->gsi_interrupt, si->interrupt_mode, si->interrupt_polarity);
+	if (ret < 0)
+		return 0;
+
+	/* Match device by Linux vIRQ */
+	if (ret != 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;
+
+	/* Set up DMA mask based on value from CSRT */
+	ret = dma_coerce_mask_and_coherent(&adev->dev,
+					   DMA_BIT_MASK(si->dma_address_width));
+	if (ret)
+		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");
+			break;
+		}
+
+		grp = (struct acpi_csrt_group *)((void *)grp + grp->length);
+	}
+
+	acpi_put_table((struct acpi_table_header *)csrt);
+}
+
+/**
+ * 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
+ *
+ * Allocated memory should be freed with appropriate acpi_dma_controller_free()
+ * call.
+ *
+ * Return:
+ * 0 on success or appropriate errno value on error.
+ */
+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 */
+	adev = ACPI_COMPANION(dev);
+	if (!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.
+ *
+ * Return:
+ * 0 on success or appropriate errno value on error.
+ */
+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.
+ *
+ * Return:
+ * 0 on success or appropriate errno value on error.
+ */
+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()
+ * @dev:	device that is unregistering as DMA controller
+ *
+ * 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_release(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
+ *
+ * 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.
+ *
+ * Return:
+ * 0, if no information is avaiable, -1 on mismatch, and 1 otherwise.
+ */
+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
+ *
+ * Return:
+ * Pointer to appropriate dma channel on success or an error pointer.
+ */
+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 acpi_device *adev = ACPI_COMPANION(dev);
+	struct list_head resource_list;
+	struct acpi_dma *adma;
+	struct dma_chan *chan = NULL;
+	int found;
+	int ret;
+
+	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);
+	ret = acpi_dev_get_resources(adev, &resource_list,
+				     acpi_dma_parse_fixed_dma, &pdata);
+	acpi_dev_free_resource_list(&resource_list);
+	if (ret < 0)
+		return ERR_PTR(ret);
+
+	if (dma_spec->slave_id < 0 || dma_spec->chan_id < 0)
+		return ERR_PTR(-ENODEV);
+
+	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 ? chan : ERR_PTR(-EPROBE_DEFER);
+}
+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.
+ *
+ * If the device has "dma-names" property the FixedDMA descriptor indices
+ * are retrieved based on those. Otherwise the function falls back using
+ * hardcoded indices.
+ *
+ * Return:
+ * Pointer to appropriate dma channel on success or an error pointer.
+ */
+struct dma_chan *acpi_dma_request_slave_chan_by_name(struct device *dev,
+		const char *name)
+{
+	int index;
+
+	index = device_property_match_string(dev, "dma-names", name);
+	if (index < 0) {
+		if (!strcmp(name, "tx"))
+			index = 0;
+		else if (!strcmp(name, "rx"))
+			index = 1;
+		else
+			return ERR_PTR(-ENODEV);
+	}
+
+	dev_dbg(dev, "Looking for DMA channel \"%s\" at index %d...\n", name, index);
+	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.
+ *
+ * Return:
+ * 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);