--- /dev/null
+/*
+ * 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/err.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
+ *
+ * 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 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
+ *
+ * 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 */
+ 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.
+ *
+ * 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()
+ *
+ * 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 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 ERR_PTR(-ENODEV);
+
+ if (acpi_bus_get_device(ACPI_HANDLE(dev), &adev))
+ return ERR_PTR(-ENODEV);
+
+ 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 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.
+ *
+ * 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)
+{
+ size_t index;
+
+ if (!strcmp(name, "tx"))
+ index = 0;
+ else if (!strcmp(name, "rx"))
+ index = 1;
+ else
+ return ERR_PTR(-ENODEV);
+
+ 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);
Code Review / kvmfornfv.git / blobdiff