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Diffstat (limited to '')
-rw-r--r-- | drivers/dma/acpi-dma.c | 473 |
1 files changed, 473 insertions, 0 deletions
diff --git a/drivers/dma/acpi-dma.c b/drivers/dma/acpi-dma.c new file mode 100644 index 000000000..52768dc8c --- /dev/null +++ b/drivers/dma/acpi-dma.c @@ -0,0 +1,473 @@ +// 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; + + /* Match device by Linux vIRQ */ + ret = acpi_register_gsi(NULL, si->gsi_interrupt, si->interrupt_mode, si->interrupt_polarity); + 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); |