diff options
| -rw-r--r-- | Documentation/acpi/enumeration.txt | 77 | ||||
| -rw-r--r-- | drivers/dma/Kconfig | 4 | ||||
| -rw-r--r-- | drivers/dma/Makefile | 1 | ||||
| -rw-r--r-- | drivers/dma/acpi-dma.c | 279 | ||||
| -rw-r--r-- | include/linux/acpi_dma.h | 116 |
5 files changed, 477 insertions, 0 deletions
diff --git a/Documentation/acpi/enumeration.txt b/Documentation/acpi/enumeration.txt index 94a656131885..2874c904f3ef 100644 --- a/Documentation/acpi/enumeration.txt +++ b/Documentation/acpi/enumeration.txt @@ -66,6 +66,83 @@ the ACPI device explicitly to acpi_platform_device_ids list defined in drivers/acpi/acpi_platform.c. This limitation is only for the platform devices, SPI and I2C devices are created automatically as described below. +DMA support +~~~~~~~~~~~ +DMA controllers enumerated via ACPI should be registered in the system to +provide generic access to their resources. For example, a driver that would +like to be accessible to slave devices via generic API call +dma_request_slave_channel() must register itself at the end of the probe +function like this: + + err = devm_acpi_dma_controller_register(dev, xlate_func, dw); + /* Handle the error if it's not a case of !CONFIG_ACPI */ + +and implement custom xlate function if needed (usually acpi_dma_simple_xlate() +is enough) which converts the FixedDMA resource provided by struct +acpi_dma_spec into the corresponding DMA channel. A piece of code for that case +could look like: + + #ifdef CONFIG_ACPI + struct filter_args { + /* Provide necessary information for the filter_func */ + ... + }; + + static bool filter_func(struct dma_chan *chan, void *param) + { + /* Choose the proper channel */ + ... + } + + static struct dma_chan *xlate_func(struct acpi_dma_spec *dma_spec, + struct acpi_dma *adma) + { + dma_cap_mask_t cap; + struct filter_args args; + + /* Prepare arguments for filter_func */ + ... + return dma_request_channel(cap, filter_func, &args); + } + #else + static struct dma_chan *xlate_func(struct acpi_dma_spec *dma_spec, + struct acpi_dma *adma) + { + return NULL; + } + #endif + +dma_request_slave_channel() will call xlate_func() for each registered DMA +controller. In the xlate function the proper channel must be chosen based on +information in struct acpi_dma_spec and the properties of the controller +provided by struct acpi_dma. + +Clients must call dma_request_slave_channel() with the string parameter that +corresponds to a specific FixedDMA resource. By default "tx" means the first +entry of the FixedDMA resource array, "rx" means the second entry. The table +below shows a layout: + + Device (I2C0) + { + ... + Method (_CRS, 0, NotSerialized) + { + Name (DBUF, ResourceTemplate () + { + FixedDMA (0x0018, 0x0004, Width32bit, _Y48) + FixedDMA (0x0019, 0x0005, Width32bit, ) + }) + ... + } + } + +So, the FixedDMA with request line 0x0018 is "tx" and next one is "rx" in +this example. + +In robust cases the client unfortunately needs to call +acpi_dma_request_slave_chan_by_index() directly and therefore choose the +specific FixedDMA resource by its index. + SPI serial bus support ~~~~~~~~~~~~~~~~~~~~~~ Slave devices behind SPI bus have SpiSerialBus resource attached to them. diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig index d5c58e839b27..afe5b1958382 100644 --- a/drivers/dma/Kconfig +++ b/drivers/dma/Kconfig @@ -326,6 +326,10 @@ config DMA_ENGINE config DMA_VIRTUAL_CHANNELS tristate +config DMA_ACPI + def_bool y + depends on ACPI + config DMA_OF def_bool y depends on OF diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile index 488e3ff85b52..268e62634bca 100644 --- a/drivers/dma/Makefile +++ b/drivers/dma/Makefile @@ -3,6 +3,7 @@ ccflags-$(CONFIG_DMADEVICES_VDEBUG) += -DVERBOSE_DEBUG obj-$(CONFIG_DMA_ENGINE) += dmaengine.o obj-$(CONFIG_DMA_VIRTUAL_CHANNELS) += virt-dma.o +obj-$(CONFIG_DMA_ACPI) += acpi-dma.o obj-$(CONFIG_DMA_OF) += of-dma.o obj-$(CONFIG_NET_DMA) += iovlock.o diff --git a/drivers/dma/acpi-dma.c b/drivers/dma/acpi-dma.c new file mode 100644 index 000000000000..ba6fc62e9651 --- /dev/null +++ b/drivers/dma/acpi-dma.c @@ -0,0 +1,279 @@ +/* + * ACPI helpers for DMA request / controller + * + * Based on of-dma.c + * + * Copyright (C) 2013, Intel Corporation + * Author: Andy Shevchenko <andriy.shevchenko@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/module.h> +#include <linux/list.h> +#include <linux/mutex.h> +#include <linux/slab.h> +#include <linux/acpi.h> +#include <linux/acpi_dma.h> + +static LIST_HEAD(acpi_dma_list); +static DEFINE_MUTEX(acpi_dma_lock); + +/** + * 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 + * + * Returns 0 on success or appropriate errno value on error. + * + * Allocated memory should be freed with appropriate acpi_dma_controller_free() + * call. + */ +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; + + /* 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. + */ +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. + */ +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_destroy(dev, devm_acpi_dma_release, NULL, NULL)); +} +EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_free); + +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 + * + * Returns pointer to appropriate dma channel on success or NULL on error. + */ +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; + + /* Check if the device was enumerated by ACPI */ + if (!dev || !ACPI_HANDLE(dev)) + return NULL; + + if (acpi_bus_get_device(ACPI_HANDLE(dev), &adev)) + return NULL; + + 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 NULL; + + mutex_lock(&acpi_dma_lock); + + list_for_each_entry(adma, &acpi_dma_list, dma_controllers) { + dma_spec->dev = adma->dev; + chan = adma->acpi_dma_xlate(dma_spec, adma); + if (chan) + break; + } + + mutex_unlock(&acpi_dma_lock); + return chan; +} +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. + * + * Returns pointer to appropriate dma channel on success or NULL on error. + */ +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 NULL; + + 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. Returns + * 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); diff --git a/include/linux/acpi_dma.h b/include/linux/acpi_dma.h new file mode 100644 index 000000000000..d09deabc7bf6 --- /dev/null +++ b/include/linux/acpi_dma.h @@ -0,0 +1,116 @@ +/* + * ACPI helpers for DMA request / controller + * + * Based on of_dma.h + * + * Copyright (C) 2013, Intel Corporation + * Author: Andy Shevchenko <andriy.shevchenko@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. + */ + +#ifndef __LINUX_ACPI_DMA_H +#define __LINUX_ACPI_DMA_H + +#include <linux/list.h> +#include <linux/device.h> +#include <linux/dmaengine.h> + +/** + * struct acpi_dma_spec - slave device DMA resources + * @chan_id: channel unique id + * @slave_id: request line unique id + * @dev: struct device of the DMA controller to be used in the filter + * function + */ +struct acpi_dma_spec { + int chan_id; + int slave_id; + struct device *dev; +}; + +/** + * struct acpi_dma - representation of the registered DMAC + * @dma_controllers: linked list node + * @dev: struct device of this controller + * @acpi_dma_xlate: callback function to find a suitable channel + * @data: private data used by a callback function + */ +struct acpi_dma { + struct list_head dma_controllers; + struct device *dev; + struct dma_chan *(*acpi_dma_xlate) + (struct acpi_dma_spec *, struct acpi_dma *); + void *data; +}; + +/* Used with acpi_dma_simple_xlate() */ +struct acpi_dma_filter_info { + dma_cap_mask_t dma_cap; + dma_filter_fn filter_fn; +}; + +#ifdef CONFIG_DMA_ACPI + +int acpi_dma_controller_register(struct device *dev, + struct dma_chan *(*acpi_dma_xlate) + (struct acpi_dma_spec *, struct acpi_dma *), + void *data); +int acpi_dma_controller_free(struct device *dev); +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 devm_acpi_dma_controller_free(struct device *dev); + +struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev, + size_t index); +struct dma_chan *acpi_dma_request_slave_chan_by_name(struct device *dev, + const char *name); + +struct dma_chan *acpi_dma_simple_xlate(struct acpi_dma_spec *dma_spec, + struct acpi_dma *adma); +#else + +static inline int acpi_dma_controller_register(struct device *dev, + struct dma_chan *(*acpi_dma_xlate) + (struct acpi_dma_spec *, struct acpi_dma *), + void *data) +{ + return -ENODEV; +} +static inline int acpi_dma_controller_free(struct device *dev) +{ + return -ENODEV; +} +static inline int devm_acpi_dma_controller_register(struct device *dev, + struct dma_chan *(*acpi_dma_xlate) + (struct acpi_dma_spec *, struct acpi_dma *), + void *data) +{ + return -ENODEV; +} +static inline void devm_acpi_dma_controller_free(struct device *dev) +{ +} + +static inline struct dma_chan *acpi_dma_request_slave_chan_by_index( + struct device *dev, size_t index) +{ + return NULL; +} +static inline struct dma_chan *acpi_dma_request_slave_chan_by_name( + struct device *dev, const char *name) +{ + return NULL; +} + +#define acpi_dma_simple_xlate NULL + +#endif + +#define acpi_dma_request_slave_channel acpi_dma_request_slave_chan_by_index + +#endif /* __LINUX_ACPI_DMA_H */ |