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Date: Thu, 9 Sep 2021 20:24:30 +0900
From: Sergey Senozhatsky <senozhatsky@...omium.org>
To: Tomasz Figa <tfiga@...omium.org>,
Hans Verkuil <hverkuil-cisco@...all.nl>
Cc: Marek Szyprowski <m.szyprowski@...sung.com>,
Dafna Hirschfeld <dafna.hirschfeld@...labora.com>,
Ricardo Ribalda <ribalda@...omium.org>,
Christoph Hellwig <hch@....de>,
Mauro Carvalho Chehab <mchehab@...nel.org>,
linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
Sergey Senozhatsky <senozhatsky@...omium.org>
Subject: [PATCHv6 8/8] videobuf2: handle non-contiguous DMA allocations
This adds support for the new noncontiguous DMA API, which
requires allocators to have two execution branches: one
for the current API, and one for the new one.
Signed-off-by: Sergey Senozhatsky <senozhatsky@...omium.org>
Acked-by: Christoph Hellwig <hch@....de>
---
.../common/videobuf2/videobuf2-dma-contig.c | 161 ++++++++++++++----
1 file changed, 130 insertions(+), 31 deletions(-)
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index 1e218bc440c6..b052a4e36961 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -17,6 +17,7 @@
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
+#include <linux/highmem.h>
#include <media/videobuf2-v4l2.h>
#include <media/videobuf2-dma-contig.h>
@@ -42,6 +43,7 @@ struct vb2_dc_buf {
struct dma_buf_attachment *db_attach;
struct vb2_buffer *vb;
+ bool non_coherent_mem;
};
/*********************************************/
@@ -75,17 +77,39 @@ static void *vb2_dc_cookie(struct vb2_buffer *vb, void *buf_priv)
return &buf->dma_addr;
}
+/*
+ * This function may fail if:
+ *
+ * - dma_buf_vmap() fails
+ * E.g. due to lack of virtual mapping address space, or due to
+ * dmabuf->ops misconfiguration.
+ *
+ * - dma_vmap_noncontiguous() fails
+ * For instance, when requested buffer size is larger than totalram_pages().
+ * Relevant for buffers that use non-coherent memory.
+ *
+ * - Queue DMA attrs have DMA_ATTR_NO_KERNEL_MAPPING set
+ * Relevant for buffers that use coherent memory.
+ */
static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv)
{
struct vb2_dc_buf *buf = buf_priv;
- struct dma_buf_map map;
- int ret;
- if (!buf->vaddr && buf->db_attach) {
- ret = dma_buf_vmap(buf->db_attach->dmabuf, &map);
- buf->vaddr = ret ? NULL : map.vaddr;
+ if (buf->vaddr)
+ return buf->vaddr;
+
+ if (buf->db_attach) {
+ struct dma_buf_map map;
+
+ if (!dma_buf_vmap(buf->db_attach->dmabuf, &map))
+ buf->vaddr = map.vaddr;
+
+ return buf->vaddr;
}
+ if (buf->non_coherent_mem)
+ buf->vaddr = dma_vmap_noncontiguous(buf->dev, buf->size,
+ buf->dma_sgt);
return buf->vaddr;
}
@@ -101,13 +125,19 @@ static void vb2_dc_prepare(void *buf_priv)
struct vb2_dc_buf *buf = buf_priv;
struct sg_table *sgt = buf->dma_sgt;
+ /* This takes care of DMABUF and user-enforced cache sync hint */
if (buf->vb->skip_cache_sync_on_prepare)
return;
- if (!sgt)
+ if (!buf->non_coherent_mem)
return;
+ /* For both USERPTR and non-coherent MMAP */
dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
+
+ /* Non-coherent MMAP only */
+ if (buf->vaddr)
+ flush_kernel_vmap_range(buf->vaddr, buf->size);
}
static void vb2_dc_finish(void *buf_priv)
@@ -115,13 +145,19 @@ static void vb2_dc_finish(void *buf_priv)
struct vb2_dc_buf *buf = buf_priv;
struct sg_table *sgt = buf->dma_sgt;
+ /* This takes care of DMABUF and user-enforced cache sync hint */
if (buf->vb->skip_cache_sync_on_finish)
return;
- if (!sgt)
+ if (!buf->non_coherent_mem)
return;
+ /* For both USERPTR and non-coherent MMAP */
dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
+
+ /* Non-coherent MMAP only */
+ if (buf->vaddr)
+ invalidate_kernel_vmap_range(buf->vaddr, buf->size);
}
/*********************************************/
@@ -135,21 +171,69 @@ static void vb2_dc_put(void *buf_priv)
if (!refcount_dec_and_test(&buf->refcount))
return;
- if (buf->sgt_base) {
- sg_free_table(buf->sgt_base);
- kfree(buf->sgt_base);
+ if (buf->non_coherent_mem) {
+ if (buf->vaddr)
+ dma_vunmap_noncontiguous(buf->dev, buf->vaddr);
+ dma_free_noncontiguous(buf->dev, buf->size,
+ buf->dma_sgt, buf->dma_dir);
+ } else {
+ if (buf->sgt_base) {
+ sg_free_table(buf->sgt_base);
+ kfree(buf->sgt_base);
+ }
+ dma_free_attrs(buf->dev, buf->size, buf->cookie,
+ buf->dma_addr, buf->attrs);
}
- dma_free_attrs(buf->dev, buf->size, buf->cookie, buf->dma_addr,
- buf->attrs);
put_device(buf->dev);
kfree(buf);
}
+static int vb2_dc_alloc_coherent(struct vb2_dc_buf *buf)
+{
+ struct vb2_queue *q = buf->vb->vb2_queue;
+
+ buf->cookie = dma_alloc_attrs(buf->dev,
+ buf->size,
+ &buf->dma_addr,
+ GFP_KERNEL | q->gfp_flags,
+ buf->attrs);
+ if (!buf->cookie)
+ return -ENOMEM;
+
+ if (q->dma_attrs & DMA_ATTR_NO_KERNEL_MAPPING)
+ return 0;
+
+ buf->vaddr = buf->cookie;
+ return 0;
+}
+
+static int vb2_dc_alloc_non_coherent(struct vb2_dc_buf *buf)
+{
+ struct vb2_queue *q = buf->vb->vb2_queue;
+
+ buf->dma_sgt = dma_alloc_noncontiguous(buf->dev,
+ buf->size,
+ buf->dma_dir,
+ GFP_KERNEL | q->gfp_flags,
+ buf->attrs);
+ if (!buf->dma_sgt)
+ return -ENOMEM;
+
+ buf->dma_addr = sg_dma_address(buf->dma_sgt->sgl);
+
+ /*
+ * For non-coherent buffers the kernel mapping is created on demand
+ * in vb2_dc_vaddr().
+ */
+ return 0;
+}
+
static void *vb2_dc_alloc(struct vb2_buffer *vb,
struct device *dev,
unsigned long size)
{
struct vb2_dc_buf *buf;
+ int ret;
if (WARN_ON(!dev))
return ERR_PTR(-EINVAL);
@@ -159,27 +243,28 @@ static void *vb2_dc_alloc(struct vb2_buffer *vb,
return ERR_PTR(-ENOMEM);
buf->attrs = vb->vb2_queue->dma_attrs;
- buf->cookie = dma_alloc_attrs(dev, size, &buf->dma_addr,
- GFP_KERNEL | vb->vb2_queue->gfp_flags,
- buf->attrs);
- if (!buf->cookie) {
- dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
- kfree(buf);
- return ERR_PTR(-ENOMEM);
- }
-
- if ((buf->attrs & DMA_ATTR_NO_KERNEL_MAPPING) == 0)
- buf->vaddr = buf->cookie;
+ buf->dma_dir = vb->vb2_queue->dma_dir;
+ buf->vb = vb;
+ buf->non_coherent_mem = vb->vb2_queue->non_coherent_mem;
+ buf->size = size;
/* Prevent the device from being released while the buffer is used */
buf->dev = get_device(dev);
- buf->size = size;
- buf->dma_dir = vb->vb2_queue->dma_dir;
+
+ if (buf->non_coherent_mem)
+ ret = vb2_dc_alloc_non_coherent(buf);
+ else
+ ret = vb2_dc_alloc_coherent(buf);
+
+ if (ret) {
+ dev_err(dev, "dma alloc of size %ld failed\n", size);
+ kfree(buf);
+ return ERR_PTR(-ENOMEM);
+ }
buf->handler.refcount = &buf->refcount;
buf->handler.put = vb2_dc_put;
buf->handler.arg = buf;
- buf->vb = vb;
refcount_set(&buf->refcount, 1);
@@ -196,9 +281,12 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
return -EINVAL;
}
- ret = dma_mmap_attrs(buf->dev, vma, buf->cookie,
- buf->dma_addr, buf->size, buf->attrs);
-
+ if (buf->non_coherent_mem)
+ ret = dma_mmap_noncontiguous(buf->dev, vma, buf->size,
+ buf->dma_sgt);
+ else
+ ret = dma_mmap_attrs(buf->dev, vma, buf->cookie, buf->dma_addr,
+ buf->size, buf->attrs);
if (ret) {
pr_err("Remapping memory failed, error: %d\n", ret);
return ret;
@@ -360,9 +448,15 @@ vb2_dc_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf,
static int vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf, struct dma_buf_map *map)
{
- struct vb2_dc_buf *buf = dbuf->priv;
+ struct vb2_dc_buf *buf;
+ void *vaddr;
- dma_buf_map_set_vaddr(map, buf->vaddr);
+ buf = dbuf->priv;
+ vaddr = vb2_dc_vaddr(buf->vb, buf);
+ if (!vaddr)
+ return -EINVAL;
+
+ dma_buf_map_set_vaddr(map, vaddr);
return 0;
}
@@ -390,6 +484,9 @@ static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
int ret;
struct sg_table *sgt;
+ if (buf->non_coherent_mem)
+ return buf->dma_sgt;
+
sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
if (!sgt) {
dev_err(buf->dev, "failed to alloc sg table\n");
@@ -567,6 +664,8 @@ static void *vb2_dc_get_userptr(struct vb2_buffer *vb, struct device *dev,
buf->dma_addr = sg_dma_address(sgt->sgl);
buf->dma_sgt = sgt;
+ buf->non_coherent_mem = 1;
+
out:
buf->size = size;
--
2.33.0.153.gba50c8fa24-goog
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