diff options
Diffstat (limited to 'drivers/dma/virt-dma.h')
| -rw-r--r-- | drivers/dma/virt-dma.h | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/drivers/dma/virt-dma.h b/drivers/dma/virt-dma.h new file mode 100644 index 000000000..181b95267 --- /dev/null +++ b/drivers/dma/virt-dma.h @@ -0,0 +1,154 @@ +/* + * 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. + */ +#ifndef VIRT_DMA_H +#define VIRT_DMA_H + +#include <linux/dmaengine.h> +#include <linux/interrupt.h> + +#include "dmaengine.h" + +struct virt_dma_desc { + struct dma_async_tx_descriptor tx; + /* protected by vc.lock */ + struct list_head node; +}; + +struct virt_dma_chan { + struct dma_chan chan; + struct tasklet_struct task; + void (*desc_free)(struct virt_dma_desc *); + + spinlock_t lock; + + /* protected by vc.lock */ + struct list_head desc_submitted; + struct list_head desc_issued; + struct list_head desc_completed; + + struct virt_dma_desc *cyclic; +}; + +static inline struct virt_dma_chan *to_virt_chan(struct dma_chan *chan) +{ + return container_of(chan, struct virt_dma_chan, chan); +} + +void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head); +void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev); +struct virt_dma_desc *vchan_find_desc(struct virt_dma_chan *, dma_cookie_t); + +/** + * vchan_tx_prep - prepare a descriptor + * vc: virtual channel allocating this descriptor + * vd: virtual descriptor to prepare + * tx_flags: flags argument passed in to prepare function + */ +static inline struct dma_async_tx_descriptor *vchan_tx_prep(struct virt_dma_chan *vc, + struct virt_dma_desc *vd, unsigned long tx_flags) +{ + extern dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *); + + dma_async_tx_descriptor_init(&vd->tx, &vc->chan); + vd->tx.flags = tx_flags; + vd->tx.tx_submit = vchan_tx_submit; + + return &vd->tx; +} + +/** + * vchan_issue_pending - move submitted descriptors to issued list + * vc: virtual channel to update + * + * vc.lock must be held by caller + */ +static inline bool vchan_issue_pending(struct virt_dma_chan *vc) +{ + list_splice_tail_init(&vc->desc_submitted, &vc->desc_issued); + return !list_empty(&vc->desc_issued); +} + +/** + * vchan_cookie_complete - report completion of a descriptor + * vd: virtual descriptor to update + * + * vc.lock must be held by caller + */ +static inline void vchan_cookie_complete(struct virt_dma_desc *vd) +{ + struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan); + dma_cookie_t cookie; + + cookie = vd->tx.cookie; + dma_cookie_complete(&vd->tx); + dev_vdbg(vc->chan.device->dev, "txd %p[%x]: marked complete\n", + vd, cookie); + list_add_tail(&vd->node, &vc->desc_completed); + + tasklet_schedule(&vc->task); +} + +/** + * vchan_cyclic_callback - report the completion of a period + * vd: virtual descriptor + */ +static inline void vchan_cyclic_callback(struct virt_dma_desc *vd) +{ + struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan); + + vc->cyclic = vd; + tasklet_schedule(&vc->task); +} + +/** + * vchan_next_desc - peek at the next descriptor to be processed + * vc: virtual channel to obtain descriptor from + * + * vc.lock must be held by caller + */ +static inline struct virt_dma_desc *vchan_next_desc(struct virt_dma_chan *vc) +{ + if (list_empty(&vc->desc_issued)) + return NULL; + + return list_first_entry(&vc->desc_issued, struct virt_dma_desc, node); +} + +/** + * vchan_get_all_descriptors - obtain all submitted and issued descriptors + * vc: virtual channel to get descriptors from + * head: list of descriptors found + * + * vc.lock must be held by caller + * + * Removes all submitted and issued descriptors from internal lists, and + * provides a list of all descriptors found + */ +static inline void vchan_get_all_descriptors(struct virt_dma_chan *vc, + struct list_head *head) +{ + list_splice_tail_init(&vc->desc_submitted, head); + list_splice_tail_init(&vc->desc_issued, head); + list_splice_tail_init(&vc->desc_completed, head); +} + +static inline void vchan_free_chan_resources(struct virt_dma_chan *vc) +{ + unsigned long flags; + LIST_HEAD(head); + + spin_lock_irqsave(&vc->lock, flags); + vchan_get_all_descriptors(vc, &head); + spin_unlock_irqrestore(&vc->lock, flags); + + vchan_dma_desc_free_list(vc, &head); +} + +#endif |