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Diffstat (limited to 'include/linux/dmaengine.h')
| -rw-r--r-- | include/linux/dmaengine.h | 359 |
1 files changed, 359 insertions, 0 deletions
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h new file mode 100644 index 00000000000..78b236ca04f --- /dev/null +++ b/include/linux/dmaengine.h @@ -0,0 +1,359 @@ +/* + * 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); + +/* --- 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 */ |