On 06/18/2013 04:08 PM, Laurent Pinchart wrote:
Hi Aaron,
A bit late, but here's a small question.
On Tuesday 15 January 2013 12:47:42 Aaron Plattner wrote:
Instead of reimplementing all of the dma_buf functionality in every driver,
create helpers drm_prime_import and drm_prime_export that implement them in
terms of new, lower-level hook functions:
gem_prime_pin: callback when a buffer is created, used to pin buffers into
GTT gem_prime_get_sg_table: convert a drm_gem_object to an sg_table for
export gem_prime_import_sg_table: convert an sg_table into a drm_gem_object
gem_prime_vmap, gem_prime_vunmap: map and unmap an object
These hooks are optional; drivers can opt in by using drm_gem_prime_import
and drm_gem_prime_export as the .gem_prime_import and .gem_prime_export
fields of struct drm_driver.
v2:
- Drop .begin_cpu_access. None of the drivers this code replaces
implemented it. Having it here was a leftover from when I was trying to
include i915 in this rework.
- Use mutex_lock instead of mutex_lock_interruptible, as these three drivers
did. This patch series shouldn't change that behavior.
- Rename helpers to gem_prime_get_sg_table and gem_prime_import_sg_table.
Rename struct sg_table* variables to 'sgt' for clarity.
- Update drm.tmpl for these new hooks.
v3:
- Pass the vaddr down to the driver. This lets drivers that just call
vunmap on the pointer avoid having to store the pointer in their GEM
private structures. - Move documentation into a /** DOC */ comment in
drm_prime.c and include it in drm.tmpl with a !P line. I tried to use !F
lines to include documentation of the individual functions from drmP.h, but
the docproc / kernel-doc scripts barf on that file, so hopefully this is
good enough for now.
- apply refcount fix from commit be8a42ae60addd8b6092535c11b42d099d6470ec
("drm/prime: drop reference on imported dma-buf come from gem")
Signed-off-by: Aaron Plattner <aplattner@xxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxx>
---
Documentation/DocBook/drm.tmpl | 4 +
drivers/gpu/drm/drm_prime.c | 186 +++++++++++++++++++++++++++++++++++++-
include/drm/drmP.h | 12 +++
3 files changed, 201 insertions(+), 1 deletion(-)
[snip]
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 7f12573..366910d 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
[snip]
+/**
+ * DOC: PRIME Helpers
+ *
+ * Drivers can implement @gem_prime_export and @gem_prime_import in terms
of + * simpler APIs by using the helper functions @drm_gem_prime_export and
+ * @drm_gem_prime_import. These functions implement dma-buf support in
terms of + * five lower-level driver callbacks:
+ *
+ * Export callbacks:
+ *
+ * - @gem_prime_pin (optional): prepare a GEM object for exporting
+ *
+ * - @gem_prime_get_sg_table: provide a scatter/gather table of pinned
pages + *
+ * - @gem_prime_vmap: vmap a buffer exported by your driver
+ *
+ * - @gem_prime_vunmap: vunmap a buffer exported by your driver
+ *
+ * Import callback:
+ *
+ * - @gem_prime_import_sg_table (import): produce a GEM object from
another + * driver's scatter/gather table
+ */
+
+struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
+ struct drm_gem_object *obj, int flags)
+{
+ if (dev->driver->gem_prime_pin) {
+ int ret = dev->driver->gem_prime_pin(obj);
+ if (ret)
+ return ERR_PTR(ret);
+ }
+ return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size,
+ 0600);
Why do you use 0600 instead of the flags passed by the caller ?
Because I copied & pasted it from i915_gem_prime_export prior to commit
5b42427fc38ecb9056c4e64deaff36d6d6ba1b67 and didn't notice until you
pointed it out just now.
+}
+EXPORT_SYMBOL(drm_gem_prime_export);
--
Aaron
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