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-rw-r--r--drivers/dma/virt-dma.h227
1 files changed, 227 insertions, 0 deletions
diff --git a/drivers/dma/virt-dma.h b/drivers/dma/virt-dma.h
new file mode 100644
index 000000000..e9f5250fb
--- /dev/null
+++ b/drivers/dma/virt-dma.h
@@ -0,0 +1,227 @@
+/* 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;
+ struct dmaengine_result tx_result;
+ /* 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 list_head desc_terminated;
+
+ 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);
+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;
+
+ vd->tx_result.result = DMA_TRANS_NOERROR;
+ vd->tx_result.residue = 0;
+
+ 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)) {
+ unsigned long flags;
+
+ spin_lock_irqsave(&vc->lock, flags);
+ list_add(&vd->node, &vc->desc_allocated);
+ spin_unlock_irqrestore(&vc->lock, flags);
+ } 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);
+
+ list_add_tail(&vd->node, &vc->desc_terminated);
+
+ 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);
+ list_splice_tail_init(&vc->desc_terminated, 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)
+{
+ LIST_HEAD(head);
+ unsigned long flags;
+
+ tasklet_kill(&vc->task);
+
+ spin_lock_irqsave(&vc->lock, flags);
+
+ list_splice_tail_init(&vc->desc_terminated, &head);
+
+ spin_unlock_irqrestore(&vc->lock, flags);
+
+ vchan_dma_desc_free_list(vc, &head);
+}
+
+#endif