| /* |
| * 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) { |
| if (vd->overide_callback) |
| vd->overide_callback(vd->overide_param); |
| else |
| 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"); |