c13c8260da
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>
338 lines
10 KiB
C
338 lines
10 KiB
C
/*
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* Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 59
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* Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* The full GNU General Public License is included in this distribution in the
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* file called COPYING.
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*/
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#ifndef DMAENGINE_H
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#define DMAENGINE_H
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#include <linux/config.h>
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#ifdef CONFIG_DMA_ENGINE
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#include <linux/device.h>
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#include <linux/uio.h>
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#include <linux/kref.h>
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#include <linux/completion.h>
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#include <linux/rcupdate.h>
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/**
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* enum dma_event - resource PNP/power managment events
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* @DMA_RESOURCE_SUSPEND: DMA device going into low power state
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* @DMA_RESOURCE_RESUME: DMA device returning to full power
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* @DMA_RESOURCE_ADDED: DMA device added to the system
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* @DMA_RESOURCE_REMOVED: DMA device removed from the system
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*/
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enum dma_event {
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DMA_RESOURCE_SUSPEND,
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DMA_RESOURCE_RESUME,
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DMA_RESOURCE_ADDED,
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DMA_RESOURCE_REMOVED,
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};
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/**
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* typedef dma_cookie_t
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*
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* if dma_cookie_t is >0 it's a DMA request cookie, <0 it's an error code
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*/
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typedef s32 dma_cookie_t;
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#define dma_submit_error(cookie) ((cookie) < 0 ? 1 : 0)
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/**
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* enum dma_status - DMA transaction status
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* @DMA_SUCCESS: transaction completed successfully
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* @DMA_IN_PROGRESS: transaction not yet processed
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* @DMA_ERROR: transaction failed
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*/
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enum dma_status {
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DMA_SUCCESS,
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DMA_IN_PROGRESS,
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DMA_ERROR,
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};
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/**
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* struct dma_chan_percpu - the per-CPU part of struct dma_chan
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* @refcount: local_t used for open-coded "bigref" counting
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* @memcpy_count: transaction counter
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* @bytes_transferred: byte counter
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*/
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struct dma_chan_percpu {
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local_t refcount;
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/* stats */
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unsigned long memcpy_count;
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unsigned long bytes_transferred;
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};
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/**
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* struct dma_chan - devices supply DMA channels, clients use them
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* @client: ptr to the client user of this chan, will be NULL when unused
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* @device: ptr to the dma device who supplies this channel, always !NULL
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* @cookie: last cookie value returned to client
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* @chan_id:
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* @class_dev:
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* @refcount: kref, used in "bigref" slow-mode
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* @slow_ref:
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* @rcu:
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* @client_node: used to add this to the client chan list
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* @device_node: used to add this to the device chan list
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* @local: per-cpu pointer to a struct dma_chan_percpu
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*/
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struct dma_chan {
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struct dma_client *client;
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struct dma_device *device;
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dma_cookie_t cookie;
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/* sysfs */
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int chan_id;
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struct class_device class_dev;
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struct kref refcount;
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int slow_ref;
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struct rcu_head rcu;
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struct list_head client_node;
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struct list_head device_node;
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struct dma_chan_percpu *local;
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};
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void dma_chan_cleanup(struct kref *kref);
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static inline void dma_chan_get(struct dma_chan *chan)
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{
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if (unlikely(chan->slow_ref))
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kref_get(&chan->refcount);
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else {
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local_inc(&(per_cpu_ptr(chan->local, get_cpu())->refcount));
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put_cpu();
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}
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}
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static inline void dma_chan_put(struct dma_chan *chan)
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{
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if (unlikely(chan->slow_ref))
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kref_put(&chan->refcount, dma_chan_cleanup);
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else {
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local_dec(&(per_cpu_ptr(chan->local, get_cpu())->refcount));
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put_cpu();
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}
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}
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/*
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* typedef dma_event_callback - function pointer to a DMA event callback
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*/
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typedef void (*dma_event_callback) (struct dma_client *client,
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struct dma_chan *chan, enum dma_event event);
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/**
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* struct dma_client - info on the entity making use of DMA services
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* @event_callback: func ptr to call when something happens
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* @chan_count: number of chans allocated
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* @chans_desired: number of chans requested. Can be +/- chan_count
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* @lock: protects access to the channels list
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* @channels: the list of DMA channels allocated
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* @global_node: list_head for global dma_client_list
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*/
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struct dma_client {
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dma_event_callback event_callback;
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unsigned int chan_count;
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unsigned int chans_desired;
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spinlock_t lock;
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struct list_head channels;
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struct list_head global_node;
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};
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/**
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* struct dma_device - info on the entity supplying DMA services
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* @chancnt: how many DMA channels are supported
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* @channels: the list of struct dma_chan
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* @global_node: list_head for global dma_device_list
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* @refcount:
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* @done:
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* @dev_id:
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* Other func ptrs: used to make use of this device's capabilities
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*/
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struct dma_device {
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unsigned int chancnt;
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struct list_head channels;
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struct list_head global_node;
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struct kref refcount;
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struct completion done;
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int dev_id;
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int (*device_alloc_chan_resources)(struct dma_chan *chan);
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void (*device_free_chan_resources)(struct dma_chan *chan);
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dma_cookie_t (*device_memcpy_buf_to_buf)(struct dma_chan *chan,
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void *dest, void *src, size_t len);
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dma_cookie_t (*device_memcpy_buf_to_pg)(struct dma_chan *chan,
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struct page *page, unsigned int offset, void *kdata,
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size_t len);
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dma_cookie_t (*device_memcpy_pg_to_pg)(struct dma_chan *chan,
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struct page *dest_pg, unsigned int dest_off,
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struct page *src_pg, unsigned int src_off, size_t len);
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enum dma_status (*device_memcpy_complete)(struct dma_chan *chan,
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dma_cookie_t cookie, dma_cookie_t *last,
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dma_cookie_t *used);
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void (*device_memcpy_issue_pending)(struct dma_chan *chan);
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};
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/* --- public DMA engine API --- */
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struct dma_client *dma_async_client_register(dma_event_callback event_callback);
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void dma_async_client_unregister(struct dma_client *client);
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void dma_async_client_chan_request(struct dma_client *client,
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unsigned int number);
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/**
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* dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
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* @chan: DMA channel to offload copy to
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* @dest: destination address (virtual)
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* @src: source address (virtual)
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* @len: length
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*
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* Both @dest and @src must be mappable to a bus address according to the
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* DMA mapping API rules for streaming mappings.
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* Both @dest and @src must stay memory resident (kernel memory or locked
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* user space pages)
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*/
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static inline dma_cookie_t dma_async_memcpy_buf_to_buf(struct dma_chan *chan,
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void *dest, void *src, size_t len)
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{
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int cpu = get_cpu();
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per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
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per_cpu_ptr(chan->local, cpu)->memcpy_count++;
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put_cpu();
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return chan->device->device_memcpy_buf_to_buf(chan, dest, src, len);
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}
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/**
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* dma_async_memcpy_buf_to_pg - offloaded copy
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* @chan: DMA channel to offload copy to
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* @page: destination page
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* @offset: offset in page to copy to
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* @kdata: source address (virtual)
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* @len: length
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*
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* Both @page/@offset and @kdata must be mappable to a bus address according
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* to the DMA mapping API rules for streaming mappings.
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* Both @page/@offset and @kdata must stay memory resident (kernel memory or
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* locked user space pages)
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*/
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static inline dma_cookie_t dma_async_memcpy_buf_to_pg(struct dma_chan *chan,
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struct page *page, unsigned int offset, void *kdata, size_t len)
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{
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int cpu = get_cpu();
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per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
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per_cpu_ptr(chan->local, cpu)->memcpy_count++;
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put_cpu();
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return chan->device->device_memcpy_buf_to_pg(chan, page, offset,
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kdata, len);
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}
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/**
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* dma_async_memcpy_buf_to_pg - offloaded copy
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* @chan: DMA channel to offload copy to
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* @dest_page: destination page
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* @dest_off: offset in page to copy to
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* @src_page: source page
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* @src_off: offset in page to copy from
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* @len: length
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*
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* Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
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* address according to the DMA mapping API rules for streaming mappings.
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* Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
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* (kernel memory or locked user space pages)
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*/
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static inline dma_cookie_t dma_async_memcpy_pg_to_pg(struct dma_chan *chan,
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struct page *dest_pg, unsigned int dest_off, struct page *src_pg,
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unsigned int src_off, size_t len)
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{
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int cpu = get_cpu();
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per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
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per_cpu_ptr(chan->local, cpu)->memcpy_count++;
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put_cpu();
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return chan->device->device_memcpy_pg_to_pg(chan, dest_pg, dest_off,
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src_pg, src_off, len);
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}
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/**
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* dma_async_memcpy_issue_pending - flush pending copies to HW
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* @chan:
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*
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* This allows drivers to push copies to HW in batches,
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* reducing MMIO writes where possible.
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*/
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static inline void dma_async_memcpy_issue_pending(struct dma_chan *chan)
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{
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return chan->device->device_memcpy_issue_pending(chan);
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}
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/**
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* dma_async_memcpy_complete - poll for transaction completion
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* @chan: DMA channel
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* @cookie: transaction identifier to check status of
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* @last: returns last completed cookie, can be NULL
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* @used: returns last issued cookie, can be NULL
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*
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* If @last and @used are passed in, upon return they reflect the driver
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* internal state and can be used with dma_async_is_complete() to check
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* the status of multiple cookies without re-checking hardware state.
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*/
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static inline enum dma_status dma_async_memcpy_complete(struct dma_chan *chan,
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dma_cookie_t cookie, dma_cookie_t *last, dma_cookie_t *used)
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{
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return chan->device->device_memcpy_complete(chan, cookie, last, used);
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}
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/**
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* dma_async_is_complete - test a cookie against chan state
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* @cookie: transaction identifier to test status of
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* @last_complete: last know completed transaction
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* @last_used: last cookie value handed out
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*
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* dma_async_is_complete() is used in dma_async_memcpy_complete()
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* the test logic is seperated for lightweight testing of multiple cookies
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*/
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static inline enum dma_status dma_async_is_complete(dma_cookie_t cookie,
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dma_cookie_t last_complete, dma_cookie_t last_used)
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{
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if (last_complete <= last_used) {
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if ((cookie <= last_complete) || (cookie > last_used))
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return DMA_SUCCESS;
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} else {
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if ((cookie <= last_complete) && (cookie > last_used))
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return DMA_SUCCESS;
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}
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return DMA_IN_PROGRESS;
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}
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/* --- DMA device --- */
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int dma_async_device_register(struct dma_device *device);
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void dma_async_device_unregister(struct dma_device *device);
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#endif /* CONFIG_DMA_ENGINE */
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#endif /* DMAENGINE_H */
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