mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2025-01-01 10:45:49 +00:00
[I/OAT]: DMA memcpy subsystem
Provides an API for offloading memory copies to DMA devices Signed-off-by: Chris Leech <christopher.leech@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Chris Leech
David S. Miller
parent
427abfa28a
commit
c13c8260da
@ -72,4 +72,6 @@ source "drivers/edac/Kconfig"
|
||||
|
||||
source "drivers/rtc/Kconfig"
|
||||
|
||||
source "drivers/dma/Kconfig"
|
||||
|
||||
endmenu
|
||||
|
||||
@ -74,3 +74,4 @@ obj-$(CONFIG_SGI_SN) += sn/
|
||||
obj-y += firmware/
|
||||
obj-$(CONFIG_CRYPTO) += crypto/
|
||||
obj-$(CONFIG_SUPERH) += sh/
|
||||
obj-$(CONFIG_DMA_ENGINE) += dma/
|
||||
|
||||
13
drivers/dma/Kconfig
Normal file
13
drivers/dma/Kconfig
Normal file
@ -0,0 +1,13 @@
|
||||
#
|
||||
# DMA engine configuration
|
||||
#
|
||||
|
||||
menu "DMA Engine support"
|
||||
|
||||
config DMA_ENGINE
|
||||
bool "Support for DMA engines"
|
||||
---help---
|
||||
DMA engines offload copy operations from the CPU to dedicated
|
||||
hardware, allowing the copies to happen asynchronously.
|
||||
|
||||
endmenu
|
||||
1
drivers/dma/Makefile
Normal file
1
drivers/dma/Makefile
Normal file
@ -0,0 +1 @@
|
||||
obj-y += dmaengine.o
|
||||
408
drivers/dma/dmaengine.c
Normal file
408
drivers/dma/dmaengine.c
Normal file
@ -0,0 +1,408 @@
|
||||
/*
|
||||
* 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 two global lists, dma_device_list and dma_client_list.
|
||||
* Both of these are protected by a mutex, dma_list_mutex.
|
||||
*
|
||||
* 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.
|
||||
*
|
||||
* Each client has a channels list, it's only modified under the client->lock
|
||||
* and in an RCU callback, so it's safe to read under rcu_read_lock().
|
||||
*
|
||||
* Each device has a kref, which is initialized to 1 when the device is
|
||||
* registered. A kref_put is done for each class_device registered. When the
|
||||
* class_device is released, the coresponding kref_put is done in the release
|
||||
* method. Every time one of the device's channels is allocated to a client,
|
||||
* a kref_get occurs. When the channel is freed, the coresponding kref_put
|
||||
* happens. The device's release function does a completion, so
|
||||
* unregister_device does a remove event, class_device_unregister, a kref_put
|
||||
* for the first reference, then waits on the completion for all other
|
||||
* references to finish.
|
||||
*
|
||||
* Each channel has an open-coded implementation of Rusty Russell's "bigref,"
|
||||
* with a kref and a per_cpu local_t. A single reference is set when on an
|
||||
* ADDED event, and removed with a REMOVE event. Net DMA client takes an
|
||||
* extra reference per outstanding transaction. The relase function does a
|
||||
* kref_put on the device. -ChrisL
|
||||
*/
|
||||
|
||||
#include <linux/init.h>
|
||||
#include <linux/module.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>
|
||||
|
||||
static DEFINE_MUTEX(dma_list_mutex);
|
||||
static LIST_HEAD(dma_device_list);
|
||||
static LIST_HEAD(dma_client_list);
|
||||
|
||||
/* --- sysfs implementation --- */
|
||||
|
||||
static ssize_t show_memcpy_count(struct class_device *cd, char *buf)
|
||||
{
|
||||
struct dma_chan *chan = container_of(cd, struct dma_chan, class_dev);
|
||||
unsigned long count = 0;
|
||||
int i;
|
||||
|
||||
for_each_cpu(i)
|
||||
count += per_cpu_ptr(chan->local, i)->memcpy_count;
|
||||
|
||||
return sprintf(buf, "%lu\n", count);
|
||||
}
|
||||
|
||||
static ssize_t show_bytes_transferred(struct class_device *cd, char *buf)
|
||||
{
|
||||
struct dma_chan *chan = container_of(cd, struct dma_chan, class_dev);
|
||||
unsigned long count = 0;
|
||||
int i;
|
||||
|
||||
for_each_cpu(i)
|
||||
count += per_cpu_ptr(chan->local, i)->bytes_transferred;
|
||||
|
||||
return sprintf(buf, "%lu\n", count);
|
||||
}
|
||||
|
||||
static ssize_t show_in_use(struct class_device *cd, char *buf)
|
||||
{
|
||||
struct dma_chan *chan = container_of(cd, struct dma_chan, class_dev);
|
||||
|
||||
return sprintf(buf, "%d\n", (chan->client ? 1 : 0));
|
||||
}
|
||||
|
||||
static struct class_device_attribute dma_class_attrs[] = {
|
||||
__ATTR(memcpy_count, S_IRUGO, show_memcpy_count, NULL),
|
||||
__ATTR(bytes_transferred, S_IRUGO, show_bytes_transferred, NULL),
|
||||
__ATTR(in_use, S_IRUGO, show_in_use, NULL),
|
||||
__ATTR_NULL
|
||||
};
|
||||
|
||||
static void dma_async_device_cleanup(struct kref *kref);
|
||||
|
||||
static void dma_class_dev_release(struct class_device *cd)
|
||||
{
|
||||
struct dma_chan *chan = container_of(cd, struct dma_chan, class_dev);
|
||||
kref_put(&chan->device->refcount, dma_async_device_cleanup);
|
||||
}
|
||||
|
||||
static struct class dma_devclass = {
|
||||
.name = "dma",
|
||||
.class_dev_attrs = dma_class_attrs,
|
||||
.release = dma_class_dev_release,
|
||||
};
|
||||
|
||||
/* --- client and device registration --- */
|
||||
|
||||
/**
|
||||
* dma_client_chan_alloc - try to allocate a channel to a client
|
||||
* @client: &dma_client
|
||||
*
|
||||
* Called with dma_list_mutex held.
|
||||
*/
|
||||
static struct dma_chan *dma_client_chan_alloc(struct dma_client *client)
|
||||
{
|
||||
struct dma_device *device;
|
||||
struct dma_chan *chan;
|
||||
unsigned long flags;
|
||||
int desc; /* allocated descriptor count */
|
||||
|
||||
/* Find a channel, any DMA engine will do */
|
||||
list_for_each_entry(device, &dma_device_list, global_node) {
|
||||
list_for_each_entry(chan, &device->channels, device_node) {
|
||||
if (chan->client)
|
||||
continue;
|
||||
|
||||
desc = chan->device->device_alloc_chan_resources(chan);
|
||||
if (desc >= 0) {
|
||||
kref_get(&device->refcount);
|
||||
kref_init(&chan->refcount);
|
||||
chan->slow_ref = 0;
|
||||
INIT_RCU_HEAD(&chan->rcu);
|
||||
chan->client = client;
|
||||
spin_lock_irqsave(&client->lock, flags);
|
||||
list_add_tail_rcu(&chan->client_node,
|
||||
&client->channels);
|
||||
spin_unlock_irqrestore(&client->lock, flags);
|
||||
return chan;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
/**
|
||||
* dma_client_chan_free - release a DMA channel
|
||||
* @chan: &dma_chan
|
||||
*/
|
||||
void dma_chan_cleanup(struct kref *kref)
|
||||
{
|
||||
struct dma_chan *chan = container_of(kref, struct dma_chan, refcount);
|
||||
chan->device->device_free_chan_resources(chan);
|
||||
chan->client = NULL;
|
||||
kref_put(&chan->device->refcount, dma_async_device_cleanup);
|
||||
}
|
||||
|
||||
static void dma_chan_free_rcu(struct rcu_head *rcu)
|
||||
{
|
||||
struct dma_chan *chan = container_of(rcu, struct dma_chan, rcu);
|
||||
int bias = 0x7FFFFFFF;
|
||||
int i;
|
||||
for_each_cpu(i)
|
||||
bias -= local_read(&per_cpu_ptr(chan->local, i)->refcount);
|
||||
atomic_sub(bias, &chan->refcount.refcount);
|
||||
kref_put(&chan->refcount, dma_chan_cleanup);
|
||||
}
|
||||
|
||||
static void dma_client_chan_free(struct dma_chan *chan)
|
||||
{
|
||||
atomic_add(0x7FFFFFFF, &chan->refcount.refcount);
|
||||
chan->slow_ref = 1;
|
||||
call_rcu(&chan->rcu, dma_chan_free_rcu);
|
||||
}
|
||||
|
||||
/**
|
||||
* dma_chans_rebalance - reallocate channels to clients
|
||||
*
|
||||
* When the number of DMA channel in the system changes,
|
||||
* channels need to be rebalanced among clients
|
||||
*/
|
||||
static void dma_chans_rebalance(void)
|
||||
{
|
||||
struct dma_client *client;
|
||||
struct dma_chan *chan;
|
||||
unsigned long flags;
|
||||
|
||||
mutex_lock(&dma_list_mutex);
|
||||
|
||||
list_for_each_entry(client, &dma_client_list, global_node) {
|
||||
while (client->chans_desired > client->chan_count) {
|
||||
chan = dma_client_chan_alloc(client);
|
||||
if (!chan)
|
||||
break;
|
||||
client->chan_count++;
|
||||
client->event_callback(client,
|
||||
chan,
|
||||
DMA_RESOURCE_ADDED);
|
||||
}
|
||||
while (client->chans_desired < client->chan_count) {
|
||||
spin_lock_irqsave(&client->lock, flags);
|
||||
chan = list_entry(client->channels.next,
|
||||
struct dma_chan,
|
||||
client_node);
|
||||
list_del_rcu(&chan->client_node);
|
||||
spin_unlock_irqrestore(&client->lock, flags);
|
||||
client->chan_count--;
|
||||
client->event_callback(client,
|
||||
chan,
|
||||
DMA_RESOURCE_REMOVED);
|
||||
dma_client_chan_free(chan);
|
||||
}
|
||||
}
|
||||
|
||||
mutex_unlock(&dma_list_mutex);
|
||||
}
|
||||
|
||||
/**
|
||||
* dma_async_client_register - allocate and register a &dma_client
|
||||
* @event_callback: callback for notification of channel addition/removal
|
||||
*/
|
||||
struct dma_client *dma_async_client_register(dma_event_callback event_callback)
|
||||
{
|
||||
struct dma_client *client;
|
||||
|
||||
client = kzalloc(sizeof(*client), GFP_KERNEL);
|
||||
if (!client)
|
||||
return NULL;
|
||||
|
||||
INIT_LIST_HEAD(&client->channels);
|
||||
spin_lock_init(&client->lock);
|
||||
client->chans_desired = 0;
|
||||
client->chan_count = 0;
|
||||
client->event_callback = event_callback;
|
||||
|
||||
mutex_lock(&dma_list_mutex);
|
||||
list_add_tail(&client->global_node, &dma_client_list);
|
||||
mutex_unlock(&dma_list_mutex);
|
||||
|
||||
return client;
|
||||
}
|
||||
|
||||
/**
|
||||
* dma_async_client_unregister - unregister a client and free the &dma_client
|
||||
* @client:
|
||||
*
|
||||
* Force frees any allocated DMA channels, frees the &dma_client memory
|
||||
*/
|
||||
void dma_async_client_unregister(struct dma_client *client)
|
||||
{
|
||||
struct dma_chan *chan;
|
||||
|
||||
if (!client)
|
||||
return;
|
||||
|
||||
rcu_read_lock();
|
||||
list_for_each_entry_rcu(chan, &client->channels, client_node)
|
||||
dma_client_chan_free(chan);
|
||||
rcu_read_unlock();
|
||||
|
||||
mutex_lock(&dma_list_mutex);
|
||||
list_del(&client->global_node);
|
||||
mutex_unlock(&dma_list_mutex);
|
||||
|
||||
kfree(client);
|
||||
dma_chans_rebalance();
|
||||
}
|
||||
|
||||
/**
|
||||
* dma_async_client_chan_request - request DMA channels
|
||||
* @client: &dma_client
|
||||
* @number: count of DMA channels requested
|
||||
*
|
||||
* Clients call dma_async_client_chan_request() to specify how many
|
||||
* DMA channels they need, 0 to free all currently allocated.
|
||||
* The resulting allocations/frees are indicated to the client via the
|
||||
* event callback.
|
||||
*/
|
||||
void dma_async_client_chan_request(struct dma_client *client,
|
||||
unsigned int number)
|
||||
{
|
||||
client->chans_desired = number;
|
||||
dma_chans_rebalance();
|
||||
}
|
||||
|
||||
/**
|
||||
* dma_async_device_register -
|
||||
* @device: &dma_device
|
||||
*/
|
||||
int dma_async_device_register(struct dma_device *device)
|
||||
{
|
||||
static int id;
|
||||
int chancnt = 0;
|
||||
struct dma_chan* chan;
|
||||
|
||||
if (!device)
|
||||
return -ENODEV;
|
||||
|
||||
init_completion(&device->done);
|
||||
kref_init(&device->refcount);
|
||||
device->dev_id = id++;
|
||||
|
||||
/* represent channels in sysfs. Probably want devs too */
|
||||
list_for_each_entry(chan, &device->channels, device_node) {
|
||||
chan->local = alloc_percpu(typeof(*chan->local));
|
||||
if (chan->local == NULL)
|
||||
continue;
|
||||
|
||||
chan->chan_id = chancnt++;
|
||||
chan->class_dev.class = &dma_devclass;
|
||||
chan->class_dev.dev = NULL;
|
||||
snprintf(chan->class_dev.class_id, BUS_ID_SIZE, "dma%dchan%d",
|
||||
device->dev_id, chan->chan_id);
|
||||
|
||||
kref_get(&device->refcount);
|
||||
class_device_register(&chan->class_dev);
|
||||
}
|
||||
|
||||
mutex_lock(&dma_list_mutex);
|
||||
list_add_tail(&device->global_node, &dma_device_list);
|
||||
mutex_unlock(&dma_list_mutex);
|
||||
|
||||
dma_chans_rebalance();
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* dma_async_device_unregister -
|
||||
* @device: &dma_device
|
||||
*/
|
||||
static void dma_async_device_cleanup(struct kref *kref)
|
||||
{
|
||||
struct dma_device *device;
|
||||
|
||||
device = container_of(kref, struct dma_device, refcount);
|
||||
complete(&device->done);
|
||||
}
|
||||
|
||||
void dma_async_device_unregister(struct dma_device* device)
|
||||
{
|
||||
struct dma_chan *chan;
|
||||
unsigned long flags;
|
||||
|
||||
mutex_lock(&dma_list_mutex);
|
||||
list_del(&device->global_node);
|
||||
mutex_unlock(&dma_list_mutex);
|
||||
|
||||
list_for_each_entry(chan, &device->channels, device_node) {
|
||||
if (chan->client) {
|
||||
spin_lock_irqsave(&chan->client->lock, flags);
|
||||
list_del(&chan->client_node);
|
||||
chan->client->chan_count--;
|
||||
spin_unlock_irqrestore(&chan->client->lock, flags);
|
||||
chan->client->event_callback(chan->client,
|
||||
chan,
|
||||
DMA_RESOURCE_REMOVED);
|
||||
dma_client_chan_free(chan);
|
||||
}
|
||||
class_device_unregister(&chan->class_dev);
|
||||
}
|
||||
dma_chans_rebalance();
|
||||
|
||||
kref_put(&device->refcount, dma_async_device_cleanup);
|
||||
wait_for_completion(&device->done);
|
||||
}
|
||||
|
||||
static int __init dma_bus_init(void)
|
||||
{
|
||||
mutex_init(&dma_list_mutex);
|
||||
return class_register(&dma_devclass);
|
||||
}
|
||||
|
||||
subsys_initcall(dma_bus_init);
|
||||
|
||||
EXPORT_SYMBOL(dma_async_client_register);
|
||||
EXPORT_SYMBOL(dma_async_client_unregister);
|
||||
EXPORT_SYMBOL(dma_async_client_chan_request);
|
||||
EXPORT_SYMBOL(dma_async_memcpy_buf_to_buf);
|
||||
EXPORT_SYMBOL(dma_async_memcpy_buf_to_pg);
|
||||
EXPORT_SYMBOL(dma_async_memcpy_pg_to_pg);
|
||||
EXPORT_SYMBOL(dma_async_memcpy_complete);
|
||||
EXPORT_SYMBOL(dma_async_memcpy_issue_pending);
|
||||
EXPORT_SYMBOL(dma_async_device_register);
|
||||
EXPORT_SYMBOL(dma_async_device_unregister);
|
||||
EXPORT_SYMBOL(dma_chan_cleanup);
|
||||
337
include/linux/dmaengine.h
Normal file
337
include/linux/dmaengine.h
Normal file
@ -0,0 +1,337 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
#ifndef DMAENGINE_H
|
||||
#define DMAENGINE_H
|
||||
#include <linux/config.h>
|
||||
#ifdef CONFIG_DMA_ENGINE
|
||||
|
||||
#include <linux/device.h>
|
||||
#include <linux/uio.h>
|
||||
#include <linux/kref.h>
|
||||
#include <linux/completion.h>
|
||||
#include <linux/rcupdate.h>
|
||||
|
||||
/**
|
||||
* enum dma_event - resource PNP/power managment events
|
||||
* @DMA_RESOURCE_SUSPEND: DMA device going into low power state
|
||||
* @DMA_RESOURCE_RESUME: DMA device returning to full power
|
||||
* @DMA_RESOURCE_ADDED: DMA device added to the system
|
||||
* @DMA_RESOURCE_REMOVED: DMA device removed from the system
|
||||
*/
|
||||
enum dma_event {
|
||||
DMA_RESOURCE_SUSPEND,
|
||||
DMA_RESOURCE_RESUME,
|
||||
DMA_RESOURCE_ADDED,
|
||||
DMA_RESOURCE_REMOVED,
|
||||
};
|
||||
|
||||
/**
|
||||
* typedef dma_cookie_t
|
||||
*
|
||||
* if dma_cookie_t is >0 it's a DMA request cookie, <0 it's an error code
|
||||
*/
|
||||
typedef s32 dma_cookie_t;
|
||||
|
||||
#define dma_submit_error(cookie) ((cookie) < 0 ? 1 : 0)
|
||||
|
||||
/**
|
||||
* enum dma_status - DMA transaction status
|
||||
* @DMA_SUCCESS: transaction completed successfully
|
||||
* @DMA_IN_PROGRESS: transaction not yet processed
|
||||
* @DMA_ERROR: transaction failed
|
||||
*/
|
||||
enum dma_status {
|
||||
DMA_SUCCESS,
|
||||
DMA_IN_PROGRESS,
|
||||
DMA_ERROR,
|
||||
};
|
||||
|
||||
/**
|
||||
* struct dma_chan_percpu - the per-CPU part of struct dma_chan
|
||||
* @refcount: local_t used for open-coded "bigref" counting
|
||||
* @memcpy_count: transaction counter
|
||||
* @bytes_transferred: byte counter
|
||||
*/
|
||||
|
||||
struct dma_chan_percpu {
|
||||
local_t refcount;
|
||||
/* stats */
|
||||
unsigned long memcpy_count;
|
||||
unsigned long bytes_transferred;
|
||||
};
|
||||
|
||||
/**
|
||||
* struct dma_chan - devices supply DMA channels, clients use them
|
||||
* @client: ptr to the client user of this chan, will be NULL when unused
|
||||
* @device: ptr to the dma device who supplies this channel, always !NULL
|
||||
* @cookie: last cookie value returned to client
|
||||
* @chan_id:
|
||||
* @class_dev:
|
||||
* @refcount: kref, used in "bigref" slow-mode
|
||||
* @slow_ref:
|
||||
* @rcu:
|
||||
* @client_node: used to add this to the client chan list
|
||||
* @device_node: used to add this to the device chan list
|
||||
* @local: per-cpu pointer to a struct dma_chan_percpu
|
||||
*/
|
||||
struct dma_chan {
|
||||
struct dma_client *client;
|
||||
struct dma_device *device;
|
||||
dma_cookie_t cookie;
|
||||
|
||||
/* sysfs */
|
||||
int chan_id;
|
||||
struct class_device class_dev;
|
||||
|
||||
struct kref refcount;
|
||||
int slow_ref;
|
||||
struct rcu_head rcu;
|
||||
|
||||
struct list_head client_node;
|
||||
struct list_head device_node;
|
||||
struct dma_chan_percpu *local;
|
||||
};
|
||||
|
||||
void dma_chan_cleanup(struct kref *kref);
|
||||
|
||||
static inline void dma_chan_get(struct dma_chan *chan)
|
||||
{
|
||||
if (unlikely(chan->slow_ref))
|
||||
kref_get(&chan->refcount);
|
||||
else {
|
||||
local_inc(&(per_cpu_ptr(chan->local, get_cpu())->refcount));
|
||||
put_cpu();
|
||||
}
|
||||
}
|
||||
|
||||
static inline void dma_chan_put(struct dma_chan *chan)
|
||||
{
|
||||
if (unlikely(chan->slow_ref))
|
||||
kref_put(&chan->refcount, dma_chan_cleanup);
|
||||
else {
|
||||
local_dec(&(per_cpu_ptr(chan->local, get_cpu())->refcount));
|
||||
put_cpu();
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* typedef dma_event_callback - function pointer to a DMA event callback
|
||||
*/
|
||||
typedef void (*dma_event_callback) (struct dma_client *client,
|
||||
struct dma_chan *chan, enum dma_event event);
|
||||
|
||||
/**
|
||||
* struct dma_client - info on the entity making use of DMA services
|
||||
* @event_callback: func ptr to call when something happens
|
||||
* @chan_count: number of chans allocated
|
||||
* @chans_desired: number of chans requested. Can be +/- chan_count
|
||||
* @lock: protects access to the channels list
|
||||
* @channels: the list of DMA channels allocated
|
||||
* @global_node: list_head for global dma_client_list
|
||||
*/
|
||||
struct dma_client {
|
||||
dma_event_callback event_callback;
|
||||
unsigned int chan_count;
|
||||
unsigned int chans_desired;
|
||||
|
||||
spinlock_t lock;
|
||||
struct list_head channels;
|
||||
struct list_head global_node;
|
||||
};
|
||||
|
||||
/**
|
||||
* struct dma_device - info on the entity supplying DMA services
|
||||
* @chancnt: how many DMA channels are supported
|
||||
* @channels: the list of struct dma_chan
|
||||
* @global_node: list_head for global dma_device_list
|
||||
* @refcount:
|
||||
* @done:
|
||||
* @dev_id:
|
||||
* Other func ptrs: used to make use of this device's capabilities
|
||||
*/
|
||||
struct dma_device {
|
||||
|
||||
unsigned int chancnt;
|
||||
struct list_head channels;
|
||||
struct list_head global_node;
|
||||
|
||||
struct kref refcount;
|
||||
struct completion done;
|
||||
|
||||
int dev_id;
|
||||
|
||||
int (*device_alloc_chan_resources)(struct dma_chan *chan);
|
||||
void (*device_free_chan_resources)(struct dma_chan *chan);
|
||||
dma_cookie_t (*device_memcpy_buf_to_buf)(struct dma_chan *chan,
|
||||
void *dest, void *src, size_t len);
|
||||
dma_cookie_t (*device_memcpy_buf_to_pg)(struct dma_chan *chan,
|
||||
struct page *page, unsigned int offset, void *kdata,
|
||||
size_t len);
|
||||
dma_cookie_t (*device_memcpy_pg_to_pg)(struct dma_chan *chan,
|
||||
struct page *dest_pg, unsigned int dest_off,
|
||||
struct page *src_pg, unsigned int src_off, size_t len);
|
||||
enum dma_status (*device_memcpy_complete)(struct dma_chan *chan,
|
||||
dma_cookie_t cookie, dma_cookie_t *last,
|
||||
dma_cookie_t *used);
|
||||
void (*device_memcpy_issue_pending)(struct dma_chan *chan);
|
||||
};
|
||||
|
||||
/* --- public DMA engine API --- */
|
||||
|
||||
struct dma_client *dma_async_client_register(dma_event_callback event_callback);
|
||||
void dma_async_client_unregister(struct dma_client *client);
|
||||
void dma_async_client_chan_request(struct dma_client *client,
|
||||
unsigned int number);
|
||||
|
||||
/**
|
||||
* dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
|
||||
* @chan: DMA channel to offload copy to
|
||||
* @dest: destination address (virtual)
|
||||
* @src: source address (virtual)
|
||||
* @len: length
|
||||
*
|
||||
* Both @dest and @src must be mappable to a bus address according to the
|
||||
* DMA mapping API rules for streaming mappings.
|
||||
* Both @dest and @src must stay memory resident (kernel memory or locked
|
||||
* user space pages)
|
||||
*/
|
||||
static inline dma_cookie_t dma_async_memcpy_buf_to_buf(struct dma_chan *chan,
|
||||
void *dest, void *src, size_t len)
|
||||
{
|
||||
int cpu = get_cpu();
|
||||
per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
|
||||
per_cpu_ptr(chan->local, cpu)->memcpy_count++;
|
||||
put_cpu();
|
||||
|
||||
return chan->device->device_memcpy_buf_to_buf(chan, dest, src, len);
|
||||
}
|
||||
|
||||
/**
|
||||
* dma_async_memcpy_buf_to_pg - offloaded copy
|
||||
* @chan: DMA channel to offload copy to
|
||||
* @page: destination page
|
||||
* @offset: offset in page to copy to
|
||||
* @kdata: source address (virtual)
|
||||
* @len: length
|
||||
*
|
||||
* Both @page/@offset and @kdata must be mappable to a bus address according
|
||||
* to the DMA mapping API rules for streaming mappings.
|
||||
* Both @page/@offset and @kdata must stay memory resident (kernel memory or
|
||||
* locked user space pages)
|
||||
*/
|
||||
static inline dma_cookie_t dma_async_memcpy_buf_to_pg(struct dma_chan *chan,
|
||||
struct page *page, unsigned int offset, void *kdata, size_t len)
|
||||
{
|
||||
int cpu = get_cpu();
|
||||
per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
|
||||
per_cpu_ptr(chan->local, cpu)->memcpy_count++;
|
||||
put_cpu();
|
||||
|
||||
return chan->device->device_memcpy_buf_to_pg(chan, page, offset,
|
||||
kdata, len);
|
||||
}
|
||||
|
||||
/**
|
||||
* dma_async_memcpy_buf_to_pg - offloaded copy
|
||||
* @chan: DMA channel to offload copy to
|
||||
* @dest_page: destination page
|
||||
* @dest_off: offset in page to copy to
|
||||
* @src_page: source page
|
||||
* @src_off: offset in page to copy from
|
||||
* @len: length
|
||||
*
|
||||
* Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
|
||||
* address according to the DMA mapping API rules for streaming mappings.
|
||||
* Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
|
||||
* (kernel memory or locked user space pages)
|
||||
*/
|
||||
static inline dma_cookie_t dma_async_memcpy_pg_to_pg(struct dma_chan *chan,
|
||||
struct page *dest_pg, unsigned int dest_off, struct page *src_pg,
|
||||
unsigned int src_off, size_t len)
|
||||
{
|
||||
int cpu = get_cpu();
|
||||
per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
|
||||
per_cpu_ptr(chan->local, cpu)->memcpy_count++;
|
||||
put_cpu();
|
||||
|
||||
return chan->device->device_memcpy_pg_to_pg(chan, dest_pg, dest_off,
|
||||
src_pg, src_off, len);
|
||||
}
|
||||
|
||||
/**
|
||||
* dma_async_memcpy_issue_pending - flush pending copies to HW
|
||||
* @chan:
|
||||
*
|
||||
* This allows drivers to push copies to HW in batches,
|
||||
* reducing MMIO writes where possible.
|
||||
*/
|
||||
static inline void dma_async_memcpy_issue_pending(struct dma_chan *chan)
|
||||
{
|
||||
return chan->device->device_memcpy_issue_pending(chan);
|
||||
}
|
||||
|
||||
/**
|
||||
* dma_async_memcpy_complete - poll for transaction completion
|
||||
* @chan: DMA channel
|
||||
* @cookie: transaction identifier to check status of
|
||||
* @last: returns last completed cookie, can be NULL
|
||||
* @used: returns last issued cookie, can be NULL
|
||||
*
|
||||
* If @last and @used are passed in, upon return they reflect the driver
|
||||
* internal state and can be used with dma_async_is_complete() to check
|
||||
* the status of multiple cookies without re-checking hardware state.
|
||||
*/
|
||||
static inline enum dma_status dma_async_memcpy_complete(struct dma_chan *chan,
|
||||
dma_cookie_t cookie, dma_cookie_t *last, dma_cookie_t *used)
|
||||
{
|
||||
return chan->device->device_memcpy_complete(chan, cookie, last, used);
|
||||
}
|
||||
|
||||
/**
|
||||
* dma_async_is_complete - test a cookie against chan state
|
||||
* @cookie: transaction identifier to test status of
|
||||
* @last_complete: last know completed transaction
|
||||
* @last_used: last cookie value handed out
|
||||
*
|
||||
* dma_async_is_complete() is used in dma_async_memcpy_complete()
|
||||
* the test logic is seperated for lightweight testing of multiple cookies
|
||||
*/
|
||||
static inline enum dma_status dma_async_is_complete(dma_cookie_t cookie,
|
||||
dma_cookie_t last_complete, dma_cookie_t last_used)
|
||||
{
|
||||
if (last_complete <= last_used) {
|
||||
if ((cookie <= last_complete) || (cookie > last_used))
|
||||
return DMA_SUCCESS;
|
||||
} else {
|
||||
if ((cookie <= last_complete) && (cookie > last_used))
|
||||
return DMA_SUCCESS;
|
||||
}
|
||||
return DMA_IN_PROGRESS;
|
||||
}
|
||||
|
||||
|
||||
/* --- DMA device --- */
|
||||
|
||||
int dma_async_device_register(struct dma_device *device);
|
||||
void dma_async_device_unregister(struct dma_device *device);
|
||||
|
||||
#endif /* CONFIG_DMA_ENGINE */
|
||||
#endif /* DMAENGINE_H */
|
||||
Loading…
Reference in New Issue
Block a user