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authorChris Leech <christopher.leech@intel.com>2006-05-23 17:18:44 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2006-06-17 21:18:43 -0700
commitc13c8260da3155f2cefb63b0d1b7dcdcb405c644 (patch)
treeecfe02fa44a423a948f5fb5ad76497da2bb7a402 /include/linux/dmaengine.h
parent427abfa28afedffadfca9dd8b067eb6d36bac53f (diff)
[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>
Diffstat (limited to 'include/linux/dmaengine.h')
-rw-r--r--include/linux/dmaengine.h337
1 files changed, 337 insertions, 0 deletions
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
new file mode 100644
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--- /dev/null
+++ b/include/linux/dmaengine.h
@@ -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 */