From: Faith Ekstrand <[email protected]>

Will be used by the UMD to optimize CPU accesses to buffers
that are frequently read by the CPU, or on which the access
pattern makes non-cacheable mappings inefficient.

Mapping buffers CPU-cached implies taking care of the CPU
cache maintenance in the UMD, unless the GPU is IO coherent.

v2:
- Add more to the commit message

v3:
- No changes

v4:
- Fix the map_wc test in panfrost_ioctl_query_bo_info()

Signed-off-by: Faith Ekstrand <[email protected]>
Signed-off-by: Boris Brezillon <[email protected]>
---
 drivers/gpu/drm/panfrost/panfrost_drv.c | 10 ++++++++--
 drivers/gpu/drm/panfrost/panfrost_gem.c |  3 +++
 include/uapi/drm/panfrost_drm.h         |  1 +
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c 
b/drivers/gpu/drm/panfrost/panfrost_drv.c
index 00c0881fa2f0..9ca08d148f56 100644
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
@@ -125,6 +125,10 @@ static int panfrost_ioctl_get_param(struct drm_device 
*ddev, void *data, struct
        return 0;
 }
 
+#define PANFROST_BO_FLAGS      (PANFROST_BO_NOEXEC | \
+                                PANFROST_BO_HEAP | \
+                                PANFROST_BO_WB_MMAP)
+
 static int panfrost_ioctl_create_bo(struct drm_device *dev, void *data,
                struct drm_file *file)
 {
@@ -134,8 +138,7 @@ static int panfrost_ioctl_create_bo(struct drm_device *dev, 
void *data,
        struct panfrost_gem_mapping *mapping;
        int ret;
 
-       if (!args->size || args->pad ||
-           (args->flags & ~(PANFROST_BO_NOEXEC | PANFROST_BO_HEAP)))
+       if (!args->size || args->pad || (args->flags & ~PANFROST_BO_FLAGS))
                return -EINVAL;
 
        /* Heaps should never be executable */
@@ -661,6 +664,9 @@ static int panfrost_ioctl_query_bo_info(struct drm_device 
*dev, void *data,
 
                if (bo->is_heap)
                        args->create_flags |= PANFROST_BO_HEAP;
+
+               if (!bo->base.map_wc)
+                       args->create_flags |= PANFROST_BO_WB_MMAP;
        }
 
        drm_gem_object_put(gem_obj);
diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c 
b/drivers/gpu/drm/panfrost/panfrost_gem.c
index da0362202d94..0e8028ee9d1f 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gem.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gem.c
@@ -320,6 +320,9 @@ panfrost_gem_create(struct drm_device *dev, size_t size, 
u32 flags)
        bo->noexec = !!(flags & PANFROST_BO_NOEXEC);
        bo->is_heap = !!(flags & PANFROST_BO_HEAP);
 
+       if (flags & PANFROST_BO_WB_MMAP)
+               bo->base.map_wc = false;
+
        return bo;
 }
 
diff --git a/include/uapi/drm/panfrost_drm.h b/include/uapi/drm/panfrost_drm.h
index e7d01e744efd..244d2f96c2d7 100644
--- a/include/uapi/drm/panfrost_drm.h
+++ b/include/uapi/drm/panfrost_drm.h
@@ -104,6 +104,7 @@ struct drm_panfrost_wait_bo {
 /* Valid flags to pass to drm_panfrost_create_bo */
 #define PANFROST_BO_NOEXEC     1
 #define PANFROST_BO_HEAP       2
+#define PANFROST_BO_WB_MMAP    4
 
 /**
  * struct drm_panfrost_create_bo - ioctl argument for creating Panfrost BOs.
-- 
2.51.0

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