// 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 <[email protected]> * Mika Westerberg <[email protected]> */ #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) { … } /** * acpi_dma_parse_csrt - parse CSRT to extract 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) { … } /** * 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) { … } EXPORT_SYMBOL_GPL(…); /** * 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) { … } EXPORT_SYMBOL_GPL(…); static void devm_acpi_dma_release(struct device *dev, void *res) { … } /** * 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) { … } EXPORT_SYMBOL_GPL(…); /** * 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) { … } EXPORT_SYMBOL_GPL(…); /** * 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 available, -1 on mismatch, and 1 otherwise. */ static int acpi_dma_update_dma_spec(struct acpi_dma *adma, struct acpi_dma_spec *dma_spec) { … } struct acpi_dma_parser_data { … }; /** * 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) { … } /** * 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) { … } EXPORT_SYMBOL_GPL(…); /** * 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) { … } EXPORT_SYMBOL_GPL(…); /** * 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) { … } EXPORT_SYMBOL_GPL(…);
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