/*
* 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
#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 - an opaque DMA cookie
*
* 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: channel ID for sysfs
* @class_dev: class device for sysfs
* @refcount: kref, used in "bigref" slow-mode
* @slow_ref: indicates that the DMA channel is free
* @rcu: the DMA channel's RCU head
* @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: reference count
* @done: IO completion struct
* @dev_id: unique device ID
* @device_alloc_chan_resources: allocate resources and return the
* number of allocated descriptors
* @device_free_chan_resources: release DMA channel's resources
* @device_memcpy_buf_to_buf: memcpy buf pointer to buf pointer
* @device_memcpy_buf_to_pg: memcpy buf pointer to struct page
* @device_memcpy_pg_to_pg: memcpy struct page/offset to struct page/offset
* @device_memcpy_complete: poll the status of an IOAT DMA transaction
* @device_memcpy_issue_pending: push appended descriptors to hardware
*/
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 from address to page
* @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_pg_to_pg - offloaded copy from page to page
* @chan: DMA channel to offload copy to
* @dest_pg: destination page
* @dest_off: offset in page to copy to
* @src_pg: 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: target DMA channel
*
* 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);
/* --- Helper iov-locking functions --- */
struct dma_page_list {
char *base_address;
int nr_pages;
struct page **pages;
};
struct dma_pinned_list {
int nr_iovecs;
struct dma_page_list page_list[0];
};
struct dma_pinned_list *dma_pin_iovec_pages(struct iovec *iov, size_t len);
void dma_unpin_iovec_pages(struct dma_pinned_list* pinned_list);
dma_cookie_t dma_memcpy_to_iovec(struct dma_chan *chan, struct iovec *iov,
struct dma_pinned_list *pinned_list, unsigned char *kdata, size_t len);
dma_cookie_t dma_memcpy_pg_to_iovec(struct dma_chan *chan, struct iovec *iov,
struct dma_pinned_list *pinned_list, struct page *page,
unsigned int offset, size_t len);
#endif /* CONFIG_DMA_ENGINE */
#endif /* DMAENGINE_H */