/* * 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 #include #include #include #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); /* * 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; LIST_HEAD(head); spin_lock_irq(&vc->lock); list_splice_tail_init(&vc->desc_completed, &head); spin_unlock_irq(&vc->lock); while (!list_empty(&head)) { struct virt_dma_desc *vd = list_first_entry(&head, struct virt_dma_desc, node); dma_async_tx_callback cb = vd->tx.callback; void *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");