/*
* Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 59
* Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* The full GNU General Public License is included in this distribution in the
* file called COPYING.
*/
/*
* This code implements the DMA subsystem. It provides a HW-neutral interface
* for other kernel code to use asynchronous memory copy capabilities,
* if present, and allows different HW DMA drivers to register as providing
* this capability.
*
* Due to the fact we are accelerating what is already a relatively fast
* operation, the code goes to great lengths to avoid additional overhead,
* such as locking.
*
* LOCKING:
*
* The subsystem keeps a global list of dma_device structs it is protected by a
* mutex, dma_list_mutex.
*
* A subsystem can get access to a channel by calling dmaengine_get() followed
* by dma_find_channel(), or if it has need for an exclusive channel it can call
* dma_request_channel(). Once a channel is allocated a reference is taken
* against its corresponding driver to disable removal.
*
* Each device has a channels list, which runs unlocked but is never modified
* once the device is registered, it's just setup by the driver.
*
* See Documentation/dmaengine.txt for more details
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/dma-mapping.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/device.h>
#include <linux/dmaengine.h>
#include <linux/hardirq.h>
#include <linux/spinlock.h>
#include <linux/percpu.h>
#include <linux/rcupdate.h>
#include <linux/mutex.h>
#include <linux/jiffies.h>
#include <linux/rculist.h>
#include <linux/idr.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/acpi_dma.h>
#include <linux/of_dma.h>
static DEFINE_MUTEX(dma_list_mutex);
static DEFINE_IDR(dma_idr);
static LIST_HEAD(dma_device_list);
static long dmaengine_ref_count;
/* --- sysfs implementation --- */
/**
* dev_to_dma_chan - convert a device pointer to the its sysfs container object
* @dev - device node
*
* Must be called under dma_list_mutex
*/
static struct dma_chan *dev_to_dma_chan(struct device *dev)
{
struct dma_chan_dev *chan_dev;
chan_dev = container_of(dev, typeof(*chan_dev), device);
return chan_dev->chan;
}
static ssize_t memcpy_count_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct dma_chan *chan;
unsigned long count = 0;
int i;
int err;
mutex_lock(&dma_list_mutex);
chan = dev_to_dma_chan(dev);
if (chan) {
for_each_possible_cpu(i)
count += per_cpu_ptr(chan->local, i)->memcpy_count;
err = sprintf(buf, "%lu\n", count);
} else
err = -ENODEV;
mutex_unlock(&dma_list_mutex);
return err;
}
static DEVICE_ATTR_RO(memcpy_count);
static ssize_t bytes_transferred_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct dma_chan *chan;
unsigned long count = 0;
int i;
int err;
mutex_lock(&dma_list_mutex);
chan = dev_to_dma_chan(dev);
if (chan) {
for_each_possible_cpu(i)
count += per_cpu_ptr(chan->local, i)->bytes_transferred;
err = sprintf(buf, "%lu\n", count);
} else
err = -ENODEV;
mutex_unlock(&dma_list_mutex);
return err;
}
static DEVICE_ATTR_RO(bytes_transferred);
static ssize_t in_use_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct dma_chan *chan;
int err;
mutex_lock(&dma_list_mutex);
chan = dev_to_dma_chan(dev);
if (chan)
err = sprintf(buf, "%d\n", chan->client_count);
else
err = -ENODEV;
mutex_unlock(&dma_list_mutex);
return err;
}
static DEVICE_ATTR_RO(in_use);
static struct attribute *dma_dev_attrs[] = {
&dev_attr_memcpy_count.attr,
&dev_attr_bytes_transferred.attr,
&dev_attr_in_use.attr,
NULL,
};
ATTRIBUTE_GROUPS(dma_dev);
static void chan_dev_release(struct device *dev)
{
struct dma_chan_dev *chan_dev;
chan_dev = container_of(dev, typeof(*chan_dev),