[PATCH v2 16/16] drm: omapdrm: gem: Implement dma_buf import
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Mon Dec 14 12:39:44 PST 2015
OMAP GEM objects backed by dma_buf reuse the current OMAP GEM object
support as much as possible. If the imported buffer is physically
contiguous its physical address will be used directly, reusing the
OMAP_BO_MEM_DMA_API code paths. Otherwise it will be mapped through the
TILER using a pages list created from the scatterlist instead of the
shmem backing storage.
Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
Changes since v1:
- Drop the dma-buf reexport check, reexport is handled by the DRM core
---
drivers/gpu/drm/omapdrm/omap_drv.h | 2 +
drivers/gpu/drm/omapdrm/omap_gem.c | 138 ++++++++++++++++++++++++------
drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c | 53 +++++++++---
3 files changed, 159 insertions(+), 34 deletions(-)
diff --git a/drivers/gpu/drm/omapdrm/omap_drv.h b/drivers/gpu/drm/omapdrm/omap_drv.h
index 97fcb892fdd7..6615b7d51ee3 100644
--- a/drivers/gpu/drm/omapdrm/omap_drv.h
+++ b/drivers/gpu/drm/omapdrm/omap_drv.h
@@ -200,6 +200,8 @@ void omap_gem_deinit(struct drm_device *dev);
struct drm_gem_object *omap_gem_new(struct drm_device *dev,
union omap_gem_size gsize, uint32_t flags);
+struct drm_gem_object *omap_gem_new_dmabuf(struct drm_device *dev, size_t size,
+ struct sg_table *sgt);
int omap_gem_new_handle(struct drm_device *dev, struct drm_file *file,
union omap_gem_size gsize, uint32_t flags, uint32_t *handle);
void omap_gem_free_object(struct drm_gem_object *obj);
diff --git a/drivers/gpu/drm/omapdrm/omap_gem.c b/drivers/gpu/drm/omapdrm/omap_gem.c
index 51580eaa37af..2beb78632279 100644
--- a/drivers/gpu/drm/omapdrm/omap_gem.c
+++ b/drivers/gpu/drm/omapdrm/omap_gem.c
@@ -33,6 +33,7 @@
#define OMAP_BO_MEM_DMA_API 0x01000000 /* memory allocated with the dma_alloc_* API */
#define OMAP_BO_MEM_SHMEM 0x02000000 /* memory allocated through shmem backing */
#define OMAP_BO_MEM_EXT 0x04000000 /* memory allocated externally */
+#define OMAP_BO_MEM_DMABUF 0x08000000 /* memory imported from a dmabuf */
#define OMAP_BO_EXT_SYNC 0x10000000 /* externally allocated sync object */
struct omap_gem_object {
@@ -49,17 +50,25 @@ struct omap_gem_object {
uint32_t roll;
/**
- * If buffer is allocated physically contiguous, the OMAP_BO_MEM_DMA_API
- * flag is set and the paddr is valid. Also if the buffer is remapped
- * in TILER and paddr_cnt > 0, then paddr is valid. But if you are using
- * the physical address and OMAP_BO_MEM_DMA_API is not set, then you
- * should be going thru omap_gem_{get,put}_paddr() to ensure the mapping
- * is not removed from under your feet.
+ * paddr contains the buffer DMA address. It is valid for
*
- * Note that OMAP_BO_SCANOUT is a hint from userspace that DMA capable
- * buffer is requested, but doesn't mean that it is. Use the
- * OMAP_BO_MEM_DMA_API flag to determine if the buffer has a DMA capable
- * physical address.
+ * - buffers allocated through the DMA mapping API (with the
+ * OMAP_BO_MEM_DMA_API flag set)
+ *
+ * - buffers imported from dmabuf (with the OMAP_BO_MEM_DMABUF flag set)
+ * if they are physically contiguous (when sgt->orig_nents == 1)
+ *
+ * - buffers mapped through the TILER when paddr_cnt is not zero, in
+ * which case the DMA address points to the TILER aperture
+ *
+ * Physically contiguous buffers have their DMA address equal to the
+ * physical address as we don't remap those buffers through the TILER.
+ *
+ * Buffers mapped to the TILER have their DMA address pointing to the
+ * TILER aperture. As TILER mappings are refcounted (through paddr_cnt)
+ * the DMA address must be accessed through omap_get_get_paddr() to
+ * ensure that the mapping won't disappear unexpectedly. References must
+ * be released with omap_gem_put_paddr().
*/
dma_addr_t paddr;
@@ -69,6 +78,12 @@ struct omap_gem_object {
uint32_t paddr_cnt;
/**
+ * If the buffer has been imported from a dmabuf the OMAP_DB_DMABUF flag
+ * is set and the sgt field is valid.
+ */
+ struct sg_table *sgt;
+
+ /**
* tiler block used when buffer is remapped in DMM/TILER.
*/
struct tiler_block *block;
@@ -166,6 +181,17 @@ static uint64_t mmap_offset(struct drm_gem_object *obj)
return drm_vma_node_offset_addr(&obj->vma_node);
}
+static bool is_contiguous(struct omap_gem_object *omap_obj)
+{
+ if (omap_obj->flags & OMAP_BO_MEM_DMA_API)
+ return true;
+
+ if ((omap_obj->flags & OMAP_BO_MEM_DMABUF) && omap_obj->sgt->nents == 1)
+ return true;
+
+ return false;
+}
+
/* -----------------------------------------------------------------------------
* Eviction
*/
@@ -384,7 +410,7 @@ static int fault_1d(struct drm_gem_object *obj,
omap_gem_cpu_sync(obj, pgoff);
pfn = page_to_pfn(omap_obj->pages[pgoff]);
} else {
- BUG_ON(!(omap_obj->flags & OMAP_BO_MEM_DMA_API));
+ BUG_ON(!is_contiguous(omap_obj));
pfn = (omap_obj->paddr >> PAGE_SHIFT) + pgoff;
}
@@ -774,8 +800,7 @@ int omap_gem_get_paddr(struct drm_gem_object *obj,
mutex_lock(&obj->dev->struct_mutex);
- if (!(omap_obj->flags & OMAP_BO_MEM_DMA_API) &&
- remap && priv->usergart) {
+ if (!is_contiguous(omap_obj) && remap && priv->usergart) {
if (omap_obj->paddr_cnt == 0) {
struct page **pages;
uint32_t npages = obj->size >> PAGE_SHIFT;
@@ -822,7 +847,7 @@ int omap_gem_get_paddr(struct drm_gem_object *obj,
omap_obj->paddr_cnt++;
*paddr = omap_obj->paddr;
- } else if (omap_obj->flags & OMAP_BO_MEM_DMA_API) {
+ } else if (is_contiguous(omap_obj)) {
*paddr = omap_obj->paddr;
} else {
ret = -EINVAL;
@@ -1290,9 +1315,6 @@ unlock:
* Constructor & Destructor
*/
-/* don't call directly.. called from GEM core when it is time to actually
- * free the object..
- */
void omap_gem_free_object(struct drm_gem_object *obj)
{
struct drm_device *dev = obj->dev;
@@ -1314,14 +1336,20 @@ void omap_gem_free_object(struct drm_gem_object *obj)
/* don't free externally allocated backing memory */
if (!(omap_obj->flags & OMAP_BO_MEM_EXT)) {
- if (omap_obj->pages)
- omap_gem_detach_pages(obj);
+ if (omap_obj->pages) {
+ if (omap_obj->flags & OMAP_BO_MEM_DMABUF)
+ kfree(omap_obj->pages);
+ else
+ omap_gem_detach_pages(obj);
+ }
if (omap_obj->flags & OMAP_BO_MEM_DMA_API) {
dma_free_writecombine(dev->dev, obj->size,
omap_obj->vaddr, omap_obj->paddr);
} else if (omap_obj->vaddr) {
vunmap(omap_obj->vaddr);
+ } else if (obj->import_attach) {
+ drm_prime_gem_destroy(obj, omap_obj->sgt);
}
}
@@ -1367,14 +1395,15 @@ struct drm_gem_object *omap_gem_new(struct drm_device *dev,
flags |= tiler_get_cpu_cache_flags();
} else if ((flags & OMAP_BO_SCANOUT) && !priv->usergart) {
/*
- * Use contiguous memory if we don't have DMM to remap
- * discontiguous buffers.
+ * OMAP_BO_SCANOUT hints that the buffer doesn't need to be
+ * tiled. However, to lower the pressure on memory allocation,
+ * use contiguous memory only if no TILER is available.
*/
flags |= OMAP_BO_MEM_DMA_API;
- } else if (!(flags & OMAP_BO_MEM_EXT)) {
+ } else if (!(flags & (OMAP_BO_MEM_EXT | OMAP_BO_MEM_DMABUF))) {
/*
- * All other buffers not backed with external memory are
- * shmem-backed.
+ * All other buffers not backed by external memory or dma_buf
+ * are shmem-backed.
*/
flags |= OMAP_BO_MEM_SHMEM;
}
@@ -1436,6 +1465,67 @@ fail:
return NULL;
}
+struct drm_gem_object *omap_gem_new_dmabuf(struct drm_device *dev, size_t size,
+ struct sg_table *sgt)
+{
+ struct omap_drm_private *priv = dev->dev_private;
+ struct omap_gem_object *omap_obj;
+ struct drm_gem_object *obj;
+ union omap_gem_size gsize;
+
+ /* Without a DMM only physically contiguous buffers can be supported. */
+ if (sgt->orig_nents != 1 && !priv->usergart)
+ return ERR_PTR(-EINVAL);
+
+ mutex_lock(&dev->struct_mutex);
+
+ gsize.bytes = PAGE_ALIGN(size);
+ obj = omap_gem_new(dev, gsize, OMAP_BO_MEM_DMABUF | OMAP_BO_WC);
+ if (!obj) {
+ obj = ERR_PTR(-ENOMEM);
+ goto done;
+ }
+
+ omap_obj = to_omap_bo(obj);
+ omap_obj->sgt = sgt;
+
+ if (sgt->orig_nents == 1) {
+ omap_obj->paddr = sg_dma_address(sgt->sgl);
+ } else {
+ /* Create pages list from sgt */
+ struct sg_page_iter iter;
+ struct page **pages;
+ unsigned int npages;
+ unsigned int i = 0;
+
+ npages = DIV_ROUND_UP(size, PAGE_SIZE);
+ pages = kcalloc(npages, sizeof(*pages), GFP_KERNEL);
+ if (!pages) {
+ omap_gem_free_object(obj);
+ obj = ERR_PTR(-ENOMEM);
+ goto done;
+ }
+
+ omap_obj->pages = pages;
+
+ for_each_sg_page(sgt->sgl, &iter, sgt->orig_nents, 0) {
+ pages[i++] = sg_page_iter_page(&iter);
+ if (i > npages)
+ break;
+ }
+
+ if (WARN_ON(i != npages)) {
+ omap_gem_free_object(obj);
+ obj = ERR_PTR(-ENOMEM);
+ goto done;
+ }
+ }
+
+done:
+ mutex_unlock(&dev->struct_mutex);
+ return obj;
+}
+
/* convenience method to construct a GEM buffer object, and userspace handle */
int omap_gem_new_handle(struct drm_device *dev, struct drm_file *file,
union omap_gem_size gsize, uint32_t flags, uint32_t *handle)
diff --git a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
index 27c297672076..19e426b698d3 100644
--- a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
+++ b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
@@ -21,6 +21,10 @@
#include "omap_drv.h"
+/* -----------------------------------------------------------------------------
+ * DMABUF Export
+ */
+
static struct sg_table *omap_gem_map_dma_buf(
struct dma_buf_attachment *attachment,
enum dma_data_direction dir)
@@ -178,15 +182,20 @@ struct dma_buf *omap_gem_prime_export(struct drm_device *dev,
return dma_buf_export(&exp_info);
}
+/* -----------------------------------------------------------------------------
+ * DMABUF Import
+ */
+
struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
- struct dma_buf *buffer)
+ struct dma_buf *dma_buf)
{
+ struct dma_buf_attachment *attach;
struct drm_gem_object *obj;
+ struct sg_table *sgt;
+ int ret;
- /* is this one of own objects? */
- if (buffer->ops == &omap_dmabuf_ops) {
- obj = buffer->priv;
- /* is it from our device? */
+ if (dma_buf->ops == &omap_dmabuf_ops) {
+ obj = dma_buf->priv;
if (obj->dev == dev) {
/*
* Importing dmabuf exported from out own gem increases
@@ -197,9 +206,33 @@ struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
}
}
- /*
- * TODO add support for importing buffers from other devices..
- * for now we don't need this but would be nice to add eventually
- */
- return ERR_PTR(-EINVAL);
+ attach = dma_buf_attach(dma_buf, dev->dev);
+ if (IS_ERR(attach))
+ return ERR_CAST(attach);
+
+ get_dma_buf(dma_buf);
+
+ sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
+ if (IS_ERR(sgt)) {
+ ret = PTR_ERR(sgt);
+ goto fail_detach;
+ }
+
+ obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
+ if (IS_ERR(obj)) {
+ ret = PTR_ERR(obj);
+ goto fail_unmap;
+ }
+
+ obj->import_attach = attach;
+
+ return obj;
+
+fail_unmap:
+ dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
+fail_detach:
+ dma_buf_detach(dma_buf, attach);
+ dma_buf_put(dma_buf);
+
+ return ERR_PTR(ret);
}
--
2.4.10
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