| /* SPDX-License-Identifier: GPL-2.0-only */ |
| /* |
| * Virtual DMA channel support for DMAengine |
| * |
| * Copyright (C) 2012 Russell King |
| */ |
| #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_allocated; |
| struct list_head desc_submitted; |
| struct list_head desc_issued; |
| struct list_head desc_completed; |
| |
| struct virt_dma_desc *cyclic; |
| struct virt_dma_desc *vd_terminated; |
| }; |
| |
| 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); |
| extern dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *); |
| extern int vchan_tx_desc_free(struct dma_async_tx_descriptor *); |
| |
| /** |
| * 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) |
| { |
| unsigned long flags; |
| |
| dma_async_tx_descriptor_init(&vd->tx, &vc->chan); |
| vd->tx.flags = tx_flags; |
| vd->tx.tx_submit = vchan_tx_submit; |
| vd->tx.desc_free = vchan_tx_desc_free; |
| |
| spin_lock_irqsave(&vc->lock, flags); |
| list_add_tail(&vd->node, &vc->desc_allocated); |
| spin_unlock_irqrestore(&vc->lock, flags); |
| |
| 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_vdesc_fini - Free or reuse a descriptor |
| * @vd: virtual descriptor to free/reuse |
| */ |
| static inline void vchan_vdesc_fini(struct virt_dma_desc *vd) |
| { |
| struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan); |
| |
| if (dmaengine_desc_test_reuse(&vd->tx)) |
| list_add(&vd->node, &vc->desc_allocated); |
| else |
| vc->desc_free(vd); |
| } |
| |
| /** |
| * 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_terminate_vdesc - Disable pending cyclic callback |
| * @vd: virtual descriptor to be terminated |
| * |
| * vc.lock must be held by caller |
| */ |
| static inline void vchan_terminate_vdesc(struct virt_dma_desc *vd) |
| { |
| struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan); |
| |
| /* free up stuck descriptor */ |
| if (vc->vd_terminated) |
| vchan_vdesc_fini(vc->vd_terminated); |
| |
| vc->vd_terminated = vd; |
| if (vc->cyclic == vd) |
| vc->cyclic = NULL; |
| } |
| |
| /** |
| * 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) |
| { |
| return list_first_entry_or_null(&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_allocated, 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) |
| { |
| struct virt_dma_desc *vd; |
| unsigned long flags; |
| LIST_HEAD(head); |
| |
| spin_lock_irqsave(&vc->lock, flags); |
| vchan_get_all_descriptors(vc, &head); |
| list_for_each_entry(vd, &head, node) |
| dmaengine_desc_clear_reuse(&vd->tx); |
| spin_unlock_irqrestore(&vc->lock, flags); |
| |
| vchan_dma_desc_free_list(vc, &head); |
| } |
| |
| /** |
| * vchan_synchronize() - synchronize callback execution to the current context |
| * @vc: virtual channel to synchronize |
| * |
| * Makes sure that all scheduled or active callbacks have finished running. For |
| * proper operation the caller has to ensure that no new callbacks are scheduled |
| * after the invocation of this function started. |
| * Free up the terminated cyclic descriptor to prevent memory leakage. |
| */ |
| static inline void vchan_synchronize(struct virt_dma_chan *vc) |
| { |
| unsigned long flags; |
| |
| tasklet_kill(&vc->task); |
| |
| spin_lock_irqsave(&vc->lock, flags); |
| if (vc->vd_terminated) { |
| vchan_vdesc_fini(vc->vd_terminated); |
| vc->vd_terminated = NULL; |
| } |
| spin_unlock_irqrestore(&vc->lock, flags); |
| } |
| |
| #endif |