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- /*
- * 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 */
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