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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Virtual DMA channel support for DMAengine4 *5 * Copyright (C) 2012 Russell King6 */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 14static 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 19dma_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 29 list_move_tail(&vd->node, &vc->desc_submitted);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}37EXPORT_SYMBOL_GPL(vchan_tx_submit);38 39/**40 * vchan_tx_desc_free - free a reusable descriptor41 * @tx: the transfer42 *43 * This function frees a previously allocated reusable descriptor. The only44 * other way is to clear the DMA_CTRL_REUSE flag and submit one last time the45 * transfer.46 *47 * Returns 0 upon success48 */49int 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}64EXPORT_SYMBOL_GPL(vchan_tx_desc_free);65 66struct 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}77EXPORT_SYMBOL_GPL(vchan_find_desc);78 79/*80 * This tasklet handles the completion of a DMA descriptor by81 * calling its callback and freeing it.82 */83static void vchan_complete(struct tasklet_struct *t)84{85 struct virt_dma_chan *vc = from_tasklet(vc, t, task);86 struct virt_dma_desc *vd, *_vd;87 struct dmaengine_desc_callback cb;88 LIST_HEAD(head);89 90 spin_lock_irq(&vc->lock);91 list_splice_tail_init(&vc->desc_completed, &head);92 vd = vc->cyclic;93 if (vd) {94 vc->cyclic = NULL;95 dmaengine_desc_get_callback(&vd->tx, &cb);96 } else {97 memset(&cb, 0, sizeof(cb));98 }99 spin_unlock_irq(&vc->lock);100 101 dmaengine_desc_callback_invoke(&cb, &vd->tx_result);102 103 list_for_each_entry_safe(vd, _vd, &head, node) {104 dmaengine_desc_get_callback(&vd->tx, &cb);105 106 list_del(&vd->node);107 dmaengine_desc_callback_invoke(&cb, &vd->tx_result);108 vchan_vdesc_fini(vd);109 }110}111 112void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head)113{114 struct virt_dma_desc *vd, *_vd;115 116 list_for_each_entry_safe(vd, _vd, head, node) {117 list_del(&vd->node);118 vchan_vdesc_fini(vd);119 }120}121EXPORT_SYMBOL_GPL(vchan_dma_desc_free_list);122 123void 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);128 INIT_LIST_HEAD(&vc->desc_allocated);129 INIT_LIST_HEAD(&vc->desc_submitted);130 INIT_LIST_HEAD(&vc->desc_issued);131 INIT_LIST_HEAD(&vc->desc_completed);132 INIT_LIST_HEAD(&vc->desc_terminated);133 134 tasklet_setup(&vc->task, vchan_complete);135 136 vc->chan.device = dmadev;137 list_add_tail(&vc->chan.device_node, &dmadev->channels);138}139EXPORT_SYMBOL_GPL(vchan_init);140 141MODULE_AUTHOR("Russell King");142MODULE_DESCRIPTION("Virtual DMA channel support for DMAengine");143MODULE_LICENSE("GPL");144