[PATCH 2/3] videobuf-dma-contig: add cache support

Federico Vaga
2012-04-12T16:36:55Z

drivers/media/video/videobuf-dma-contig.c | 199 +++++++++++++++++++++-------
include/media/videobuf-dma-contig.h | 10 ++
2 files changed, 159 insertions(+), 50 deletions(-)

diff --git a/drivers/media/video/videobuf-dma-contig.c b/drivers/media/video/videobuf-dma-contig.c
index c969111..b6b5cc1 100644
--- a/drivers/media/video/videobuf-dma-contig.c
+++ b/drivers/media/video/videobuf-dma-contig.c
@@ -27,6 +27,7 @@ struct videobuf_dma_contig_memory {
u32 magic;
void *vaddr;
dma_addr_t dma_handle;
+ bool cached;
unsigned long size;
};

@@ -37,8 +38,58 @@ struct videobuf_dma_contig_memory {
BUG(); \
}

-static void
-videobuf_vm_open(struct vm_area_struct *vma)
+static int __videobuf_dc_alloc(struct device *dev,
+ struct videobuf_dma_contig_memory *mem,
+ unsigned long size, unsigned long flags)
+{
+ mem->size = size;
+ if (mem->cached) {
+ mem->vaddr = alloc_pages_exact(mem->size, flags | GFP_DMA);
+ if (mem->vaddr) {
+ int err;
+
+ mem->dma_handle = dma_map_single(dev, mem->vaddr,
+ mem->size,
+ DMA_FROM_DEVICE);
+ err = dma_mapping_error(dev, mem->dma_handle);
+ if (err) {
+ dev_err(dev, "dma_map_single failed\n");
+
+ free_pages_exact(mem->vaddr, mem->size);
+ mem->vaddr = 0;
+ return err;
+ }
+ }
+ } else
+ mem->vaddr = dma_alloc_coherent(dev, mem->size,
+ &mem->dma_handle, flags);
+
+ if (!mem->vaddr) {
+ dev_err(dev, "memory alloc size %ld failed\n", mem->size);
+ return -ENOMEM;
+ }
+
+ dev_dbg(dev, "dma mapped data is at %p (%ld)\n", mem->vaddr, mem->size);
+
+ return 0;
+}
+
+static void __videobuf_dc_free(struct device *dev,
+ struct videobuf_dma_contig_memory *mem)
+{
+ if (mem->cached) {
+ if (!mem->vaddr)
+ return;
+ dma_unmap_single(dev, mem->dma_handle, mem->size,
+ DMA_FROM_DEVICE);
+ free_pages_exact(mem->vaddr, mem->size);
+ } else
+ dma_free_coherent(dev, mem->size, mem->vaddr, mem->dma_handle);
+
+ mem->vaddr = NULL;
+}
+
+static void videobuf_vm_open(struct vm_area_struct *vma)
{
struct videobuf_mapping *map = vma->vm_private_data;

@@ -91,12 +142,11 @@ static void videobuf_vm_close(struct vm_area_struct *vma)
dev_dbg(q->dev, "buf[%d] freeing %p\n",
i, mem->vaddr);

- dma_free_coherent(q->dev, mem->size,
- mem->vaddr, mem->dma_handle);
+ __videobuf_dc_free(q->dev, mem);
mem->vaddr = NULL;
}

- q->bufs[i]->map = NULL;
+ q->bufs[i]->map = NULL;
q->bufs[i]->baddr = 0;
}

@@ -107,8 +157,8 @@ static void videobuf_vm_close(struct vm_area_struct *vma)
}

static const struct vm_operations_struct videobuf_vm_ops = {
- .open = videobuf_vm_open,
- .close = videobuf_vm_close,
+ .open = videobuf_vm_open,
+ .close = videobuf_vm_close,
};

/**
@@ -178,26 +228,38 @@ static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem,
pages_done++;
}

- out_up:
+out_up:
up_read(&current->mm->mmap_sem);

return ret;
}

-static struct videobuf_buffer *__videobuf_alloc_vb(size_t size)
+static struct videobuf_buffer *__videobuf_alloc_vb(size_t size, bool cached)
{
struct videobuf_dma_contig_memory *mem;
struct videobuf_buffer *vb;

vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
if (vb) {
- mem = vb->priv = ((char *)vb) + size;
+ vb->priv = ((char *)vb) + size;
+ mem = vb->priv;
mem->magic = MAGIC_DC_MEM;
+ mem->cached = cached;
}

return vb;
}

+static struct videobuf_buffer *__videobuf_alloc_uncached(size_t size)
+{
+ return __videobuf_alloc_vb(size, false);
+}
+
+static struct videobuf_buffer *__videobuf_alloc_cached(size_t size)
+{
+ return __videobuf_alloc_vb(size, true);
+}
+
static void *__videobuf_to_vaddr(struct videobuf_buffer *buf)
{
struct videobuf_dma_contig_memory *mem = buf->priv;
@@ -235,28 +297,32 @@ static int __videobuf_iolock(struct videobuf_queue *q,
return videobuf_dma_contig_user_get(mem, vb);

/* allocate memory for the read() method */
- mem->size = PAGE_ALIGN(vb->size);
- mem->vaddr = dma_alloc_coherent(q->dev, mem->size,
- &mem->dma_handle, GFP_KERNEL);
- if (!mem->vaddr) {
- dev_err(q->dev, "dma_alloc_coherent %ld failed\n",
- mem->size);
+ if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(vb->size),
+ GFP_KERNEL))
return -ENOMEM;
- }
-
- dev_dbg(q->dev, "dma_alloc_coherent data is at %p (%ld)\n",
- mem->vaddr, mem->size);
break;
case V4L2_MEMORY_OVERLAY:
default:
- dev_dbg(q->dev, "%s memory method OVERLAY/unknown\n",
- __func__);
+ dev_dbg(q->dev, "%s memory method OVERLAY/unknown\n", __func__);
return -EINVAL;
}

return 0;
}

+static int __videobuf_sync(struct videobuf_queue *q,
+ struct videobuf_buffer *buf)
+{
+ struct videobuf_dma_contig_memory *mem = buf->priv;
+ BUG_ON(!mem);
+ MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
+
+ dma_sync_single_for_cpu(q->dev, mem->dma_handle, mem->size,
+ DMA_FROM_DEVICE);
+
+ return 0;
+}
+
static int __videobuf_mmap_mapper(struct videobuf_queue *q,
struct videobuf_buffer *buf,
struct vm_area_struct *vma)
@@ -265,6 +331,8 @@ static int __videobuf_mmap_mapper(struct videobuf_queue *q,
struct videobuf_mapping *map;
int retval;
unsigned long size;
+ unsigned long pos, start = vma->vm_start;
+ struct page *page;

dev_dbg(q->dev, "%s\n", __func__);

@@ -282,41 +350,50 @@ static int __videobuf_mmap_mapper(struct videobuf_queue *q,
BUG_ON(!mem);
MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);

- mem->size = PAGE_ALIGN(buf->bsize);
- mem->vaddr = dma_alloc_coherent(q->dev, mem->size,
- &mem->dma_handle, GFP_KERNEL);
- if (!mem->vaddr) {
- dev_err(q->dev, "dma_alloc_coherent size %ld failed\n",
- mem->size);
+ if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(buf->bsize),
+ GFP_KERNEL | __GFP_COMP))
goto error;
- }
- dev_dbg(q->dev, "dma_alloc_coherent data is at addr %p (size %ld)\n",
- mem->vaddr, mem->size);

/* Try to remap memory */

size = vma->vm_end - vma->vm_start;
size = (size < mem->size) ? size : mem->size;

- vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
- retval = remap_pfn_range(vma, vma->vm_start,
- mem->dma_handle >> PAGE_SHIFT,
- size, vma->vm_page_prot);
- if (retval) {
- dev_err(q->dev, "mmap: remap failed with error %d. ", retval);
- dma_free_coherent(q->dev, mem->size,
- mem->vaddr, mem->dma_handle);
- goto error;
+ if (!mem->cached)
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+
+ pos = (unsigned long)mem->vaddr;
+
+ while (size > 0) {
+ page = virt_to_page((void *)pos);
+ if (NULL == page) {
+ dev_err(q->dev, "mmap: virt_to_page failed\n");
+ __videobuf_dc_free(q->dev, mem);
+ goto error;
+ }
+ retval = vm_insert_page(vma, start, page);
+ if (retval) {
+ dev_err(q->dev, "mmap: insert failed with error %d\n",
+ retval);
+ __videobuf_dc_free(q->dev, mem);
+ goto error;
+ }
+ start += PAGE_SIZE;
+ pos += PAGE_SIZE;
+
+ if (size > PAGE_SIZE)
+ size -= PAGE_SIZE;
+ else
+ size = 0;
}

- vma->vm_ops = &videobuf_vm_ops;
- vma->vm_flags |= VM_DONTEXPAND;
+ vma->vm_ops = &videobuf_vm_ops;
+ vma->vm_flags |= VM_DONTEXPAND;
vma->vm_private_data = map;

dev_dbg(q->dev, "mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n",
map, q, vma->vm_start, vma->vm_end,
- (long int)buf->bsize,
- vma->vm_pgoff, buf->i);
+ (long int)buf->bsize, vma->vm_pgoff, buf->i);

videobuf_vm_open(vma);

@@ -328,12 +405,20 @@ error:
}

static struct videobuf_qtype_ops qops = {
- .magic = MAGIC_QTYPE_OPS,
+ .magic = MAGIC_QTYPE_OPS,
+ .alloc_vb = __videobuf_alloc_uncached,
+ .iolock = __videobuf_iolock,
+ .mmap_mapper = __videobuf_mmap_mapper,
+ .vaddr = __videobuf_to_vaddr,
+};

- .alloc_vb = __videobuf_alloc_vb,
- .iolock = __videobuf_iolock,
- .mmap_mapper = __videobuf_mmap_mapper,
- .vaddr = __videobuf_to_vaddr,
+static struct videobuf_qtype_ops qops_cached = {
+ .magic = MAGIC_QTYPE_OPS,
+ .alloc_vb = __videobuf_alloc_cached,
+ .iolock = __videobuf_iolock,
+ .sync = __videobuf_sync,
+ .mmap_mapper = __videobuf_mmap_mapper,
+ .vaddr = __videobuf_to_vaddr,
};

void videobuf_queue_dma_contig_init(struct videobuf_queue *q,
@@ -351,6 +436,20 @@ void videobuf_queue_dma_contig_init(struct videobuf_queue *q,
}
EXPORT_SYMBOL_GPL(videobuf_queue_dma_contig_init);

+void videobuf_queue_dma_contig_init_cached(struct videobuf_queue *q,
+ const struct videobuf_queue_ops *ops,
+ struct device *dev,
+ spinlock_t *irqlock,
+ enum v4l2_buf_type type,
+ enum v4l2_field field,
+ unsigned int msize,
+ void *priv, struct mutex *ext_lock)
+{
+ videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
+ priv, &qops_cached, ext_lock);
+}
+EXPORT_SYMBOL_GPL(videobuf_queue_dma_contig_init_cached);
+
dma_addr_t videobuf_to_dma_contig(struct videobuf_buffer *buf)
{
struct videobuf_dma_contig_memory *mem = buf->priv;
@@ -389,7 +488,7 @@ void videobuf_dma_contig_free(struct videobuf_queue *q,

/* read() method */
if (mem->vaddr) {
- dma_free_coherent(q->dev, mem->size, mem->vaddr, mem->dma_handle);
+ __videobuf_dc_free(q->dev, mem);
mem->vaddr = NULL;
}
}
diff --git a/include/media/videobuf-dma-contig.h b/include/media/videobuf-dma-contig.h
index f0ed825..f473aeb 100644
--- a/include/media/videobuf-dma-contig.h
+++ b/include/media/videobuf-dma-contig.h
@@ -26,6 +26,16 @@ void videobuf_queue_dma_contig_init(struct videobuf_queue *q,
void *priv,
struct mutex *ext_lock);

+void videobuf_queue_dma_contig_init_cached(struct videobuf_queue *q,
+ const struct videobuf_queue_ops *ops,
+ struct device *dev,
+ spinlock_t *irqlock,
+ enum v4l2_buf_type type,
+ enum v4l2_field field,
+ unsigned int msize,
+ void *priv,
+ struct mutex *ext_lock);
+
dma_addr_t videobuf_to_dma_contig(struct videobuf_buffer *buf);
void videobuf_dma_contig_free(struct videobuf_queue *q,
struct videobuf_buffer *buf);
--
1.7.7.6