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

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Virtual DMA channel support for DMAengine
 *
 * Copyright (C) 2012 Russell King
 */
#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(struct tasklet_struct *t)
{
	struct virt_dma_chan *vc = from_tasklet(vc, t, task);
	struct virt_dma_desc *vd, *_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, &vd->tx_result);

	list_for_each_entry_safe(vd, _vd, &head, node) {
		dmaengine_desc_get_callback(&vd->tx, &cb);

		list_del(&vd->node);
		dmaengine_desc_callback_invoke(&cb, &vd->tx_result);
		vchan_vdesc_fini(vd);
	}
}

void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head)
{
	struct virt_dma_desc *vd, *_vd;

	list_for_each_entry_safe(vd, _vd, head, node) {
		list_del(&vd->node);
		vchan_vdesc_fini(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);
	INIT_LIST_HEAD(&vc->desc_terminated);

	tasklet_setup(&vc->task, vchan_complete);

	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
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
50437bff RK	2	/*
	3	* Virtual DMA channel support for DMAengine
	4	*
	5	* Copyright (C) 2012 Russell King
50437bff RK	6	*/
	7	#include <linux/device.h>
	8	#include <linux/dmaengine.h>
	9	#include <linux/module.h>
	10	#include <linux/spinlock.h>
	11
	12	#include "virt-dma.h"
	13
	14	static struct virt_dma_desc to_virt_desc(struct dma_async_tx_descriptor tx)
	15	{
	16	return container_of(tx, struct virt_dma_desc, tx);
	17	}
	18
	19	dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *tx)
	20	{
	21	struct virt_dma_chan *vc = to_virt_chan(tx->chan);
	22	struct virt_dma_desc *vd = to_virt_desc(tx);
	23	unsigned long flags;
	24	dma_cookie_t cookie;
	25
	26	spin_lock_irqsave(&vc->lock, flags);
	27	cookie = dma_cookie_assign(tx);
	28
13bb26ae	29	list_move_tail(&vd->node, &vc->desc_submitted);
50437bff RK	30	spin_unlock_irqrestore(&vc->lock, flags);
	31
	32	dev_dbg(vc->chan.device->dev, "vchan %p: txd %p[%x]: submitted\n",
	33	vc, vd, cookie);
	34
	35	return cookie;
	36	}
	37	EXPORT_SYMBOL_GPL(vchan_tx_submit);
	38
13bb26ae RJ	39	/**
	40	* vchan_tx_desc_free - free a reusable descriptor
	41	* @tx: the transfer
	42	*
	43	* This function frees a previously allocated reusable descriptor. The only
	44	* other way is to clear the DMA_CTRL_REUSE flag and submit one last time the
	45	* transfer.
	46	*
	47	* Returns 0 upon success
	48	*/
	49	int vchan_tx_desc_free(struct dma_async_tx_descriptor *tx)
	50	{
	51	struct virt_dma_chan *vc = to_virt_chan(tx->chan);
	52	struct virt_dma_desc *vd = to_virt_desc(tx);
	53	unsigned long flags;
	54
	55	spin_lock_irqsave(&vc->lock, flags);
	56	list_del(&vd->node);
	57	spin_unlock_irqrestore(&vc->lock, flags);
	58
	59	dev_dbg(vc->chan.device->dev, "vchan %p: txd %p[%x]: freeing\n",
	60	vc, vd, vd->tx.cookie);
	61	vc->desc_free(vd);
	62	return 0;
	63	}
	64	EXPORT_SYMBOL_GPL(vchan_tx_desc_free);
	65
fe045874 RK	66	struct virt_dma_desc vchan_find_desc(struct virt_dma_chan vc,
	67	dma_cookie_t cookie)
	68	{
	69	struct virt_dma_desc *vd;
	70
	71	list_for_each_entry(vd, &vc->desc_issued, node)
	72	if (vd->tx.cookie == cookie)
	73	return vd;
	74
	75	return NULL;
	76	}
	77	EXPORT_SYMBOL_GPL(vchan_find_desc);
	78
50437bff RK	79	/*
	80	* This tasklet handles the completion of a DMA descriptor by
	81	* calling its callback and freeing it.
	82	*/
3f7a6604	83	static void vchan_complete(struct tasklet_struct *t)
50437bff	84	{
3f7a6604	85	struct virt_dma_chan *vc = from_tasklet(vc, t, task);
fdb980fb	86	struct virt_dma_desc vd, _vd;
4f03ac6a	87	struct dmaengine_desc_callback cb;
50437bff RK	88	LIST_HEAD(head);
	89
	90	spin_lock_irq(&vc->lock);
	91	list_splice_tail_init(&vc->desc_completed, &head);
571fa740 RK	92	vd = vc->cyclic;
	93	if (vd) {
	94	vc->cyclic = NULL;
4f03ac6a DJ	95	dmaengine_desc_get_callback(&vd->tx, &cb);
	96	} else {
	97	memset(&cb, 0, sizeof(cb));
571fa740	98	}
50437bff RK	99	spin_unlock_irq(&vc->lock);
50437bff RK	100
09d5b702	101	dmaengine_desc_callback_invoke(&cb, &vd->tx_result);
571fa740	102
fdb980fb	103	list_for_each_entry_safe(vd, _vd, &head, node) {
4f03ac6a	104	dmaengine_desc_get_callback(&vd->tx, &cb);
50437bff RK	105
50437bff RK	106	list_del(&vd->node);
09d5b702	107	dmaengine_desc_callback_invoke(&cb, &vd->tx_result);
24461d97	108	vchan_vdesc_fini(vd);
50437bff RK	109	}
	110	}
	111
	112	void vchan_dma_desc_free_list(struct virt_dma_chan vc, struct list_head head)
	113	{
fdb980fb AS	114	struct virt_dma_desc vd, _vd;
	115
	116	list_for_each_entry_safe(vd, _vd, head, node) {
b167f94d SH	117	list_del(&vd->node);
b167f94d SH	118	vchan_vdesc_fini(vd);
50437bff RK	119	}
	120	}
	121	EXPORT_SYMBOL_GPL(vchan_dma_desc_free_list);
	122
	123	void vchan_init(struct virt_dma_chan vc, struct dma_device dmadev)
	124	{
	125	dma_cookie_init(&vc->chan);
	126
	127	spin_lock_init(&vc->lock);
13bb26ae	128	INIT_LIST_HEAD(&vc->desc_allocated);
50437bff RK	129	INIT_LIST_HEAD(&vc->desc_submitted);
	130	INIT_LIST_HEAD(&vc->desc_issued);
	131	INIT_LIST_HEAD(&vc->desc_completed);
f8821011	132	INIT_LIST_HEAD(&vc->desc_terminated);
50437bff	133
3f7a6604	134	tasklet_setup(&vc->task, vchan_complete);
50437bff RK	135
	136	vc->chan.device = dmadev;
	137	list_add_tail(&vc->chan.device_node, &dmadev->channels);
	138	}
	139	EXPORT_SYMBOL_GPL(vchan_init);
	140
	141	MODULE_AUTHOR("Russell King");
	142	MODULE_LICENSE("GPL");