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From fd0d8a09c8d928459d37ae535825018bb0594357 Mon Sep 17 00:00:00 2001
From: John Stultz <jstultz@google.com>
Date: Mon, 11 Sep 2023 10:30:32 +0800
Subject: [PATCH 2/2] FROMLIST: dma-heap: Provide accessors so that in-kernel
drivers can allocate dmabufs from specific heaps
This allows drivers who don't want to create their own
DMA-BUF exporter to be able to allocate DMA-BUFs directly
from existing DMA-BUF Heaps.
There is some concern that the premise of DMA-BUF heaps is
that userland knows better about what type of heap memory
is needed for a pipeline, so it would likely be best for
drivers to import and fill DMA-BUFs allocated by userland
instead of allocating one themselves, but this is still
up for debate.
[Yong: Fix the checkpatch alignment warning]
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: T.J. Mercier <tjmercier@google.com>
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Signed-off-by: Vijayanand Jitta <quic_vjitta@quicinc.com>
Signed-off-by: Atul Dhudase <quic_adhudase@quicinc.com>
Upstream-Status: Submitted [https://lore.kernel.org/lkml/20230911023038.30649-4-yong.wu@mediatek.com/]
---
drivers/dma-buf/dma-heap.c | 60 ++++++++++++++++++++++++++++----------
include/linux/dma-heap.h | 25 ++++++++++++++++
2 files changed, 69 insertions(+), 16 deletions(-)
diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c
index 59328045975a..e17705427b23 100644
--- a/drivers/dma-buf/dma-heap.c
+++ b/drivers/dma-buf/dma-heap.c
@@ -54,12 +54,15 @@ static dev_t dma_heap_devt;
static struct class *dma_heap_class;
static DEFINE_XARRAY_ALLOC(dma_heap_minors);
-static int dma_heap_buffer_alloc(struct dma_heap *heap, size_t len,
- unsigned int fd_flags,
- unsigned int heap_flags)
+struct dma_buf *dma_heap_buffer_alloc(struct dma_heap *heap, size_t len,
+ unsigned int fd_flags,
+ unsigned int heap_flags)
{
- struct dma_buf *dmabuf;
- int fd;
+ if (fd_flags & ~DMA_HEAP_VALID_FD_FLAGS)
+ return ERR_PTR(-EINVAL);
+
+ if (heap_flags & ~DMA_HEAP_VALID_HEAP_FLAGS)
+ return ERR_PTR(-EINVAL);
/*
* Allocations from all heaps have to begin
@@ -67,9 +70,20 @@ static int dma_heap_buffer_alloc(struct dma_heap *heap, size_t len,
*/
len = PAGE_ALIGN(len);
if (!len)
- return -EINVAL;
+ return ERR_PTR(-EINVAL);
- dmabuf = heap->ops->allocate(heap, len, fd_flags, heap_flags);
+ return heap->ops->allocate(heap, len, fd_flags, heap_flags);
+}
+EXPORT_SYMBOL_GPL(dma_heap_buffer_alloc);
+
+static int dma_heap_bufferfd_alloc(struct dma_heap *heap, size_t len,
+ unsigned int fd_flags,
+ unsigned int heap_flags)
+{
+ struct dma_buf *dmabuf;
+ int fd;
+
+ dmabuf = dma_heap_buffer_alloc(heap, len, fd_flags, heap_flags);
if (IS_ERR(dmabuf))
return PTR_ERR(dmabuf);
@@ -107,15 +121,9 @@ static long dma_heap_ioctl_allocate(struct file *file, void *data)
if (heap_allocation->fd)
return -EINVAL;
- if (heap_allocation->fd_flags & ~DMA_HEAP_VALID_FD_FLAGS)
- return -EINVAL;
-
- if (heap_allocation->heap_flags & ~DMA_HEAP_VALID_HEAP_FLAGS)
- return -EINVAL;
-
- fd = dma_heap_buffer_alloc(heap, heap_allocation->len,
- heap_allocation->fd_flags,
- heap_allocation->heap_flags);
+ fd = dma_heap_bufferfd_alloc(heap, heap_allocation->len,
+ heap_allocation->fd_flags,
+ heap_allocation->heap_flags);
if (fd < 0)
return fd;
@@ -220,6 +228,7 @@ const char *dma_heap_get_name(struct dma_heap *heap)
{
return heap->name;
}
+EXPORT_SYMBOL_GPL(dma_heap_get_name);
struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
{
@@ -305,6 +314,24 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
kfree(heap);
return err_ret;
}
+EXPORT_SYMBOL_GPL(dma_heap_add);
+
+struct dma_heap *dma_heap_find(const char *name)
+{
+ struct dma_heap *h;
+
+ mutex_lock(&heap_list_lock);
+ list_for_each_entry(h, &heap_list, list) {
+ if (!strcmp(h->name, name)) {
+ kref_get(&h->refcount);
+ mutex_unlock(&heap_list_lock);
+ return h;
+ }
+ }
+ mutex_unlock(&heap_list_lock);
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(dma_heap_find);
static void dma_heap_release(struct kref *ref)
{
@@ -330,6 +357,7 @@ void dma_heap_put(struct dma_heap *h)
kref_put(&h->refcount, dma_heap_release);
mutex_unlock(&heap_list_lock);
}
+EXPORT_SYMBOL_GPL(dma_heap_put);
static char *dma_heap_devnode(const struct device *dev, umode_t *mode)
{
diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h
index f8c986dd9a8b..31f44d83f11b 100644
--- a/include/linux/dma-heap.h
+++ b/include/linux/dma-heap.h
@@ -65,10 +65,35 @@ const char *dma_heap_get_name(struct dma_heap *heap);
*/
struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info);
+/**
+ * dma_heap_find - get the heap registered with the specified name
+ * @name: Name of the DMA-Heap to find
+ *
+ * Returns:
+ * The DMA-Heap with the provided name.
+ *
+ * NOTE: DMA-Heaps returned from this function MUST be released using
+ * dma_heap_put() when the user is done to enable the heap to be unloaded.
+ */
+struct dma_heap *dma_heap_find(const char *name);
+
/**
* dma_heap_put - drops a reference to a dmabuf heap, potentially freeing it
* @heap: the heap whose reference count to decrement
*/
void dma_heap_put(struct dma_heap *heap);
+/**
+ * dma_heap_buffer_alloc - Allocate dma-buf from a dma_heap
+ * @heap: DMA-Heap to allocate from
+ * @len: size to allocate in bytes
+ * @fd_flags: flags to set on returned dma-buf fd
+ * @heap_flags: flags to pass to the dma heap
+ *
+ * This is for internal dma-buf allocations only. Free returned buffers with dma_buf_put().
+ */
+struct dma_buf *dma_heap_buffer_alloc(struct dma_heap *heap, size_t len,
+ unsigned int fd_flags,
+ unsigned int heap_flags);
+
#endif /* _DMA_HEAPS_H */
--
2.25.1
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