/*
* 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>
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_list_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 */
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;
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 || !ACPI_HANDLE(dev))
return ERR_PTR(-ENODEV);
if (acpi_bus_get_device(ACPI_HANDLE(dev), &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.
*
* 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)
{
size_t index;
if (!strcmp(name, "tx"))
index = 0;
else if (!strcmp(name, "rx"))
index = 1;
else
return ERR_PTR(-ENODEV);
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);
