/* * 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> #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 != 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 */ 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() * * 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, "found 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);