[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_move_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);

/**
 * vchan_tx_desc_free - free a reusable descriptor
 * @tx: the transfer
 *
 * This function frees a previously allocated reusable descriptor. The only
 * other way is to clear the DMA_CTRL_REUSE flag and submit one last time the
 * transfer.
 *
 * Returns 0 upon success
 */
int vchan_tx_desc_free(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;

	spin_lock_irqsave(&vc->lock, flags);
	list_del(&vd->node);
	spin_unlock_irqrestore(&vc->lock, flags);

	dev_dbg(vc->chan.device->dev, "vchan %p: txd %p[%x]: freeing\n",
		vc, vd, vd->tx.cookie);
	vc->desc_free(vd);
	return 0;
}
EXPORT_SYMBOL_GPL(vchan_tx_desc_free);

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;
	struct dmaengine_desc_callback cb;
	LIST_HEAD(head);

	spin_lock_irq(&vc->lock);
	list_splice_tail_init(&vc->desc_completed, &head);
	vd = vc->cyclic;
	if (vd) {
		vc->cyclic = NULL;
		dmaengine_desc_get_callback(&vd->tx, &cb);
	} else {
		memset(&cb, 0, sizeof(cb));
	}
	spin_unlock_irq(&vc->lock);

	dmaengine_desc_callback_invoke(&cb, NULL);

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

		list_del(&vd->node);
		if (dmaengine_desc_test_reuse(&vd->tx))
			list_add(&vd->node, &vc->desc_allocated);
		else
			vc->desc_free(vd);

		dmaengine_desc_callback_invoke(&cb, NULL);
	}
}

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);
		if (dmaengine_desc_test_reuse(&vd->tx)) {
			list_move_tail(&vd->node, &vc->desc_allocated);
		} else {
			dev_dbg(vc->chan.device->dev, "txd %p: freeing\n", vd);
			list_del(&vd->node);
			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_allocated);
	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
13bb26ae	32	list_move_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
13bb26ae RJ	42	/**
	43	* vchan_tx_desc_free - free a reusable descriptor
	44	* @tx: the transfer
	45	*
	46	* This function frees a previously allocated reusable descriptor. The only
	47	* other way is to clear the DMA_CTRL_REUSE flag and submit one last time the
	48	* transfer.
	49	*
	50	* Returns 0 upon success
	51	*/
	52	int vchan_tx_desc_free(struct dma_async_tx_descriptor *tx)
	53	{
	54	struct virt_dma_chan *vc = to_virt_chan(tx->chan);
	55	struct virt_dma_desc *vd = to_virt_desc(tx);
	56	unsigned long flags;
	57
	58	spin_lock_irqsave(&vc->lock, flags);
	59	list_del(&vd->node);
	60	spin_unlock_irqrestore(&vc->lock, flags);
	61
	62	dev_dbg(vc->chan.device->dev, "vchan %p: txd %p[%x]: freeing\n",
	63	vc, vd, vd->tx.cookie);
	64	vc->desc_free(vd);
	65	return 0;
	66	}
	67	EXPORT_SYMBOL_GPL(vchan_tx_desc_free);
	68
fe045874 RK	69	struct virt_dma_desc vchan_find_desc(struct virt_dma_chan vc,
	70	dma_cookie_t cookie)
	71	{
	72	struct virt_dma_desc *vd;
	73
	74	list_for_each_entry(vd, &vc->desc_issued, node)
	75	if (vd->tx.cookie == cookie)
	76	return vd;
	77
	78	return NULL;
	79	}
	80	EXPORT_SYMBOL_GPL(vchan_find_desc);
	81
50437bff RK	82	/*
	83	* This tasklet handles the completion of a DMA descriptor by
	84	* calling its callback and freeing it.
	85	*/
	86	static void vchan_complete(unsigned long arg)
	87	{
	88	struct virt_dma_chan vc = (struct virt_dma_chan )arg;
571fa740	89	struct virt_dma_desc *vd;
4f03ac6a	90	struct dmaengine_desc_callback cb;
50437bff RK	91	LIST_HEAD(head);
	92
	93	spin_lock_irq(&vc->lock);
	94	list_splice_tail_init(&vc->desc_completed, &head);
571fa740 RK	95	vd = vc->cyclic;
	96	if (vd) {
	97	vc->cyclic = NULL;
4f03ac6a DJ	98	dmaengine_desc_get_callback(&vd->tx, &cb);
	99	} else {
	100	memset(&cb, 0, sizeof(cb));
571fa740	101	}
50437bff RK	102	spin_unlock_irq(&vc->lock);
50437bff RK	103
4f03ac6a	104	dmaengine_desc_callback_invoke(&cb, NULL);
571fa740	105
50437bff	106	while (!list_empty(&head)) {
571fa740	107	vd = list_first_entry(&head, struct virt_dma_desc, node);
4f03ac6a	108	dmaengine_desc_get_callback(&vd->tx, &cb);
50437bff RK	109
50437bff RK	110	list_del(&vd->node);
13bb26ae RJ	111	if (dmaengine_desc_test_reuse(&vd->tx))
	112	list_add(&vd->node, &vc->desc_allocated);
	113	else
	114	vc->desc_free(vd);
50437bff	115
4f03ac6a	116	dmaengine_desc_callback_invoke(&cb, NULL);
50437bff RK	117	}
	118	}
	119
	120	void vchan_dma_desc_free_list(struct virt_dma_chan vc, struct list_head head)
	121	{
	122	while (!list_empty(head)) {
	123	struct virt_dma_desc *vd = list_first_entry(head,
	124	struct virt_dma_desc, node);
13bb26ae RJ	125	if (dmaengine_desc_test_reuse(&vd->tx)) {
	126	list_move_tail(&vd->node, &vc->desc_allocated);
	127	} else {
	128	dev_dbg(vc->chan.device->dev, "txd %p: freeing\n", vd);
	129	list_del(&vd->node);
	130	vc->desc_free(vd);
	131	}
50437bff RK	132	}
	133	}
	134	EXPORT_SYMBOL_GPL(vchan_dma_desc_free_list);
	135
	136	void vchan_init(struct virt_dma_chan vc, struct dma_device dmadev)
	137	{
	138	dma_cookie_init(&vc->chan);
	139
	140	spin_lock_init(&vc->lock);
13bb26ae	141	INIT_LIST_HEAD(&vc->desc_allocated);
50437bff RK	142	INIT_LIST_HEAD(&vc->desc_submitted);
	143	INIT_LIST_HEAD(&vc->desc_issued);
	144	INIT_LIST_HEAD(&vc->desc_completed);
	145
	146	tasklet_init(&vc->task, vchan_complete, (unsigned long)vc);
	147
	148	vc->chan.device = dmadev;
	149	list_add_tail(&vc->chan.device_node, &dmadev->channels);
	150	}
	151	EXPORT_SYMBOL_GPL(vchan_init);
	152
	153	MODULE_AUTHOR("Russell King");
	154	MODULE_LICENSE("GPL");