[PATCH 3/3] gbm: Add entry points for mapping and unmapping bos

[Ander Conselvan de Oliveira]

Add gbm_bo_map() and gbm_bo_unmap(). This lets a user access the
contents of a bo using the CPU.

---

I'm not sure about the extra flags. We do have GBM_BO_USE_WRITE but
that is defined to always work with GBM_BO_USE_CURSOR_64X64. Reusing
that would imply that these buffers are always mappable or an API
change.
---
 src/gbm/backends/dri/gbm_dri.c     |    4 ++++
 src/gbm/backends/intel/gbm_intel.c |   21 +++++++++++++++++++++
 src/gbm/backends/intel/gbm_intel.h |    2 ++
 src/gbm/main/gbm.c                 |   25 +++++++++++++++++++++++++
 src/gbm/main/gbm.h                 |   14 ++++++++++++++
 src/gbm/main/gbmint.h              |    2 ++
 6 files changed, 68 insertions(+)

diff --git a/src/gbm/backends/dri/gbm_dri.c b/src/gbm/backends/dri/gbm_dri.c
index 9998308..bdd1c85 100644
--- a/src/gbm/backends/dri/gbm_dri.c
+++ b/src/gbm/backends/dri/gbm_dri.c
@@ -315,6 +315,10 @@ gbm_dri_is_format_supported(struct gbm_device *gbm,
        usage & GBM_BO_USE_RENDERING)
       return 0;
 
+   if (usage & GBM_BO_USE_CPU_WRITE ||
+       usage & GBM_BO_USE_CPU_READ)
+      return 0;
+
    return 1;
 }
 
diff --git a/src/gbm/backends/intel/gbm_intel.c b/src/gbm/backends/intel/gbm_intel.c
index 9f17df7..f8baa98 100644
--- a/src/gbm/backends/intel/gbm_intel.c
+++ b/src/gbm/backends/intel/gbm_intel.c
@@ -73,6 +73,24 @@ gbm_intel_bo_write(struct gbm_bo *bo, const void *buf, size_t count)
    return drm_intel_bo_unmap(ibo->bo);
 }
 
+static void *
+gbm_intel_bo_map(struct gbm_bo *bo)
+{
+   struct gbm_intel_bo *ibo = gbm_intel_bo(bo);
+
+   drm_intel_bo_map(ibo->bo, 1);
+
+   return ibo->bo->virtual;
+}
+
+static void
+gbm_intel_bo_unmap(struct gbm_bo *bo)
+{
+   struct gbm_intel_bo *ibo = gbm_intel_bo(bo);
+
+   drm_intel_bo_unmap(ibo->bo);
+}
+
 static void
 gbm_intel_bo_destroy(struct gbm_bo *_bo)
 {
@@ -102,6 +120,7 @@ gbm_intel_bo_create_with_bo(struct gbm_device *gbm,
       return NULL;
 
    ibo->bo = bo;
+   ibo->usage = usage;
 
    ibo->base.base.gbm = gbm;
    ibo->base.base.width = width;
@@ -225,6 +244,8 @@ gbm_intel_device_create(int fd)
    igbm->base.base.bo_export = gbm_intel_bo_export;
    igbm->base.base.is_format_supported = gbm_intel_is_format_supported;
    igbm->base.base.bo_write = gbm_intel_bo_write;
+   igbm->base.base.bo_map = gbm_intel_bo_map;
+   igbm->base.base.bo_unmap = gbm_intel_bo_unmap;
    igbm->base.base.bo_destroy = gbm_intel_bo_destroy;
    igbm->base.base.destroy = gbm_intel_destroy;
    igbm->base.base.surface_create = gbm_intel_surface_create;
diff --git a/src/gbm/backends/intel/gbm_intel.h b/src/gbm/backends/intel/gbm_intel.h
index 4691ecc..8136c78 100644
--- a/src/gbm/backends/intel/gbm_intel.h
+++ b/src/gbm/backends/intel/gbm_intel.h
@@ -46,6 +46,8 @@ struct gbm_intel_device {
 struct gbm_intel_bo {
    struct gbm_drm_bo base;
 
+   uint32_t usage;
+
    drm_intel_bo *bo;
    uint32_t name;
 };
diff --git a/src/gbm/main/gbm.c b/src/gbm/main/gbm.c
index b68ead0..f41b4c9 100644
--- a/src/gbm/main/gbm.c
+++ b/src/gbm/main/gbm.c
@@ -250,6 +250,31 @@ gbm_bo_write(struct gbm_bo *bo, const void *buf, size_t count)
    return bo->gbm->bo_write(bo, buf, count);
 }
 
+/** Map a buffer object in CPU accesible memory
+ *
+ * \param bo The buffer object to be mapped
+ * \return Pointer to the mapped buffer object or NULL on failure
+ */
+GBM_EXPORT void *
+gbm_bo_map(struct gbm_bo *bo)
+{
+   if (bo->gbm->bo_map)
+      return bo->gbm->bo_map(bo);
+   else
+      return NULL;
+}
+
+/** Unmap a preivously mapped buffer object
+ *
+ * \param The buffer object to be unmapped
+ */
+GBM_EXPORT void
+gbm_bo_unmap(struct gbm_bo *bo)
+{
+   if (bo->gbm->bo_unmap)
+      bo->gbm->bo_unmap(bo);
+}
+
 /** Get the gbm device used to create the buffer object
  *
  * \param bo The buffer object
diff --git a/src/gbm/main/gbm.h b/src/gbm/main/gbm.h
index 3854c4c..b3942d3 100644
--- a/src/gbm/main/gbm.h
+++ b/src/gbm/main/gbm.h
@@ -207,6 +207,14 @@ enum gbm_bo_flags {
     * combinations.
     */
    GBM_BO_USE_WRITE    = (1 << 3),
+   /**
+    * Buffer can be mapped with gbm_bo_map() for writing.
+    */
+   GBM_BO_USE_CPU_WRITE = (1 << 4),
+   /**
+    * Buffer can be mapped with gbm_bo_map() for reading.
+    */
+   GBM_BO_USE_CPU_READ = (1 << 5),
 };
 
 int
@@ -262,6 +270,12 @@ gbm_bo_get_handle(struct gbm_bo *bo);
 int
 gbm_bo_write(struct gbm_bo *bo, const void *buf, size_t count);
 
+void *
+gbm_bo_map(struct gbm_bo *bo);
+
+void
+gbm_bo_unmap(struct gbm_bo *bo);
+
 void
 gbm_bo_set_user_data(struct gbm_bo *bo, void *data,
 		     void (*destroy_user_data)(struct gbm_bo *, void *));
diff --git a/src/gbm/main/gbmint.h b/src/gbm/main/gbmint.h
index a8cf49e..f17a46f 100644
--- a/src/gbm/main/gbmint.h
+++ b/src/gbm/main/gbmint.h
@@ -70,6 +70,8 @@ struct gbm_device {
                                void *buffer, uint32_t usage);
    int (*bo_export)(struct gbm_bo *bo, uint32_t type, void **buffer);
    int (*bo_write)(struct gbm_bo *bo, const void *buf, size_t data);
+   void *(*bo_map)(struct gbm_bo *bo);
+   void (*bo_unmap)(struct gbm_bo *bo);
    void (*bo_destroy)(struct gbm_bo *bo);
 
    struct gbm_surface *(*surface_create)(struct gbm_device *gbm,
-- 
1.7.9.5