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123 lines
2.9 KiB
123 lines
2.9 KiB
/* |
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* Virtual DMA channel support for DMAengine |
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* |
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* Copyright (C) 2012 Russell King |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License version 2 as |
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* published by the Free Software Foundation. |
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*/ |
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#include <linux/device.h> |
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#include <linux/dmaengine.h> |
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#include <linux/module.h> |
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#include <linux/spinlock.h> |
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#include "virt-dma.h" |
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static struct virt_dma_desc *to_virt_desc(struct dma_async_tx_descriptor *tx) |
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{ |
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return container_of(tx, struct virt_dma_desc, tx); |
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} |
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dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *tx) |
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{ |
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struct virt_dma_chan *vc = to_virt_chan(tx->chan); |
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struct virt_dma_desc *vd = to_virt_desc(tx); |
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unsigned long flags; |
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dma_cookie_t cookie; |
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spin_lock_irqsave(&vc->lock, flags); |
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cookie = dma_cookie_assign(tx); |
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list_add_tail(&vd->node, &vc->desc_submitted); |
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spin_unlock_irqrestore(&vc->lock, flags); |
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dev_dbg(vc->chan.device->dev, "vchan %p: txd %p[%x]: submitted\n", |
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vc, vd, cookie); |
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return cookie; |
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} |
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EXPORT_SYMBOL_GPL(vchan_tx_submit); |
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struct virt_dma_desc *vchan_find_desc(struct virt_dma_chan *vc, |
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dma_cookie_t cookie) |
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{ |
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struct virt_dma_desc *vd; |
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list_for_each_entry(vd, &vc->desc_issued, node) |
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if (vd->tx.cookie == cookie) |
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return vd; |
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return NULL; |
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} |
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EXPORT_SYMBOL_GPL(vchan_find_desc); |
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/* |
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* This tasklet handles the completion of a DMA descriptor by |
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* calling its callback and freeing it. |
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*/ |
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static void vchan_complete(unsigned long arg) |
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{ |
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struct virt_dma_chan *vc = (struct virt_dma_chan *)arg; |
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struct virt_dma_desc *vd; |
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dma_async_tx_callback cb = NULL; |
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void *cb_data = NULL; |
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LIST_HEAD(head); |
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spin_lock_irq(&vc->lock); |
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list_splice_tail_init(&vc->desc_completed, &head); |
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vd = vc->cyclic; |
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if (vd) { |
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vc->cyclic = NULL; |
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cb = vd->tx.callback; |
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cb_data = vd->tx.callback_param; |
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} |
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spin_unlock_irq(&vc->lock); |
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if (cb) |
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cb(cb_data); |
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while (!list_empty(&head)) { |
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vd = list_first_entry(&head, struct virt_dma_desc, node); |
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cb = vd->tx.callback; |
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cb_data = vd->tx.callback_param; |
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list_del(&vd->node); |
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vc->desc_free(vd); |
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if (cb) |
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cb(cb_data); |
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} |
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} |
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void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head) |
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{ |
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while (!list_empty(head)) { |
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struct virt_dma_desc *vd = list_first_entry(head, |
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struct virt_dma_desc, node); |
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list_del(&vd->node); |
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dev_dbg(vc->chan.device->dev, "txd %p: freeing\n", vd); |
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vc->desc_free(vd); |
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} |
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} |
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EXPORT_SYMBOL_GPL(vchan_dma_desc_free_list); |
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void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev) |
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{ |
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dma_cookie_init(&vc->chan); |
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spin_lock_init(&vc->lock); |
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INIT_LIST_HEAD(&vc->desc_submitted); |
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INIT_LIST_HEAD(&vc->desc_issued); |
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INIT_LIST_HEAD(&vc->desc_completed); |
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tasklet_init(&vc->task, vchan_complete, (unsigned long)vc); |
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vc->chan.device = dmadev; |
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list_add_tail(&vc->chan.device_node, &dmadev->channels); |
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} |
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EXPORT_SYMBOL_GPL(vchan_init); |
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MODULE_AUTHOR("Russell King"); |
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MODULE_LICENSE("GPL");
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