[linux-2.6-block.git] / drivers / dma / virt-dma.c

/*
 * Virtual DMA channel support for DMAengine
 *
 * Copyright (C) 2012 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/device.h>
#include <linux/dmaengine.h>
#include <linux/module.h>
#include <linux/spinlock.h>

#include "virt-dma.h"

static struct virt_dma_desc *to_virt_desc(struct dma_async_tx_descriptor *tx)
{
	return container_of(tx, struct virt_dma_desc, tx);
}

dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *tx)
{
	struct virt_dma_chan *vc = to_virt_chan(tx->chan);
	struct virt_dma_desc *vd = to_virt_desc(tx);
	unsigned long flags;
	dma_cookie_t cookie;

	spin_lock_irqsave(&vc->lock, flags);
	cookie = dma_cookie_assign(tx);

	list_add_tail(&vd->node, &vc->desc_submitted);
	spin_unlock_irqrestore(&vc->lock, flags);

	dev_dbg(vc->chan.device->dev, "vchan %p: txd %p[%x]: submitted\n",
		vc, vd, cookie);

	return cookie;
}
EXPORT_SYMBOL_GPL(vchan_tx_submit);

struct virt_dma_desc *vchan_find_desc(struct virt_dma_chan *vc,
	dma_cookie_t cookie)
{
	struct virt_dma_desc *vd;

	list_for_each_entry(vd, &vc->desc_issued, node)
		if (vd->tx.cookie == cookie)
			return vd;

	return NULL;
}
EXPORT_SYMBOL_GPL(vchan_find_desc);

/*
 * This tasklet handles the completion of a DMA descriptor by
 * calling its callback and freeing it.
 */
static void vchan_complete(unsigned long arg)
{
	struct virt_dma_chan *vc = (struct virt_dma_chan *)arg;
	struct virt_dma_desc *vd;
	dma_async_tx_callback cb = NULL;
	void *cb_data = NULL;
	LIST_HEAD(head);

	spin_lock_irq(&vc->lock);
	list_splice_tail_init(&vc->desc_completed, &head);
	vd = vc->cyclic;
	if (vd) {
		vc->cyclic = NULL;
		cb = vd->tx.callback;
		cb_data = vd->tx.callback_param;
	}
	spin_unlock_irq(&vc->lock);

	if (cb)
		cb(cb_data);

	while (!list_empty(&head)) {
		vd = list_first_entry(&head, struct virt_dma_desc, node);
		cb = vd->tx.callback;
		cb_data = vd->tx.callback_param;

		list_del(&vd->node);

		vc->desc_free(vd);

		if (cb)
			cb(cb_data);
	}
}

void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head)
{
	while (!list_empty(head)) {
		struct virt_dma_desc *vd = list_first_entry(head,
			struct virt_dma_desc, node);
		list_del(&vd->node);
		dev_dbg(vc->chan.device->dev, "txd %p: freeing\n", vd);
		vc->desc_free(vd);
	}
}
EXPORT_SYMBOL_GPL(vchan_dma_desc_free_list);

void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev)
{
	dma_cookie_init(&vc->chan);

	spin_lock_init(&vc->lock);
	INIT_LIST_HEAD(&vc->desc_submitted);
	INIT_LIST_HEAD(&vc->desc_issued);
	INIT_LIST_HEAD(&vc->desc_completed);

	tasklet_init(&vc->task, vchan_complete, (unsigned long)vc);

	vc->chan.device = dmadev;
	list_add_tail(&vc->chan.device_node, &dmadev->channels);
}
EXPORT_SYMBOL_GPL(vchan_init);

MODULE_AUTHOR("Russell King");
MODULE_LICENSE("GPL");
Commit	Line	Data
50437bff RK	1	/*
	2	* Virtual DMA channel support for DMAengine
	3	*
	4	* Copyright (C) 2012 Russell King
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*/
	10	#include <linux/device.h>
	11	#include <linux/dmaengine.h>
	12	#include <linux/module.h>
	13	#include <linux/spinlock.h>
	14
	15	#include "virt-dma.h"
	16
	17	static struct virt_dma_desc to_virt_desc(struct dma_async_tx_descriptor tx)
	18	{
	19	return container_of(tx, struct virt_dma_desc, tx);
	20	}
	21
	22	dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *tx)
	23	{
	24	struct virt_dma_chan *vc = to_virt_chan(tx->chan);
	25	struct virt_dma_desc *vd = to_virt_desc(tx);
	26	unsigned long flags;
	27	dma_cookie_t cookie;
	28
	29	spin_lock_irqsave(&vc->lock, flags);
	30	cookie = dma_cookie_assign(tx);
	31
8c8fe97b	32	list_add_tail(&vd->node, &vc->desc_submitted);
50437bff RK	33	spin_unlock_irqrestore(&vc->lock, flags);
	34
	35	dev_dbg(vc->chan.device->dev, "vchan %p: txd %p[%x]: submitted\n",
	36	vc, vd, cookie);
	37
	38	return cookie;
	39	}
	40	EXPORT_SYMBOL_GPL(vchan_tx_submit);
	41
fe045874 RK	42	struct virt_dma_desc vchan_find_desc(struct virt_dma_chan vc,
	43	dma_cookie_t cookie)
	44	{
	45	struct virt_dma_desc *vd;
	46
	47	list_for_each_entry(vd, &vc->desc_issued, node)
	48	if (vd->tx.cookie == cookie)
	49	return vd;
	50
	51	return NULL;
	52	}
	53	EXPORT_SYMBOL_GPL(vchan_find_desc);
	54
50437bff RK	55	/*
	56	* This tasklet handles the completion of a DMA descriptor by
	57	* calling its callback and freeing it.
	58	*/
	59	static void vchan_complete(unsigned long arg)
	60	{
	61	struct virt_dma_chan vc = (struct virt_dma_chan )arg;
571fa740 RK	62	struct virt_dma_desc *vd;
	63	dma_async_tx_callback cb = NULL;
	64	void *cb_data = NULL;
50437bff RK	65	LIST_HEAD(head);
	66
	67	spin_lock_irq(&vc->lock);
	68	list_splice_tail_init(&vc->desc_completed, &head);
571fa740 RK	69	vd = vc->cyclic;
	70	if (vd) {
	71	vc->cyclic = NULL;
	72	cb = vd->tx.callback;
	73	cb_data = vd->tx.callback_param;
	74	}
50437bff RK	75	spin_unlock_irq(&vc->lock);
50437bff RK	76
571fa740 RK	77	if (cb)
	78	cb(cb_data);
	79
50437bff	80	while (!list_empty(&head)) {
571fa740 RK	81	vd = list_first_entry(&head, struct virt_dma_desc, node);
	82	cb = vd->tx.callback;
	83	cb_data = vd->tx.callback_param;
50437bff RK	84
50437bff RK	85	list_del(&vd->node);
8c8fe97b JN	86
8c8fe97b JN	87	vc->desc_free(vd);
50437bff RK	88
	89	if (cb)
	90	cb(cb_data);
	91	}
	92	}
	93
	94	void vchan_dma_desc_free_list(struct virt_dma_chan vc, struct list_head head)
	95	{
	96	while (!list_empty(head)) {
	97	struct virt_dma_desc *vd = list_first_entry(head,
	98	struct virt_dma_desc, node);
8c8fe97b JN	99	list_del(&vd->node);
	100	dev_dbg(vc->chan.device->dev, "txd %p: freeing\n", vd);
	101	vc->desc_free(vd);
50437bff RK	102	}
	103	}
	104	EXPORT_SYMBOL_GPL(vchan_dma_desc_free_list);
	105
	106	void vchan_init(struct virt_dma_chan vc, struct dma_device dmadev)
	107	{
	108	dma_cookie_init(&vc->chan);
	109
	110	spin_lock_init(&vc->lock);
	111	INIT_LIST_HEAD(&vc->desc_submitted);
	112	INIT_LIST_HEAD(&vc->desc_issued);
	113	INIT_LIST_HEAD(&vc->desc_completed);
	114
	115	tasklet_init(&vc->task, vchan_complete, (unsigned long)vc);
	116
	117	vc->chan.device = dmadev;
	118	list_add_tail(&vc->chan.device_node, &dmadev->channels);
	119	}
	120	EXPORT_SYMBOL_GPL(vchan_init);
	121
	122	MODULE_AUTHOR("Russell King");
	123	MODULE_LICENSE("GPL");