| // 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 and IRQ */ |
| if (si->mmio_base_low != lower_32_bits(mem) || |
| si->mmio_base_high != upper_32_bits(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; |
| |
| /* 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"); |
| 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 */ |
| 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 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) |
| return ERR_PTR(-ENODEV); |
| |
| adev = ACPI_COMPANION(dev); |
| if (!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. |
| * |
| * 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); |