From: Imre Deak <imre.deak@intel.com>
To: intel-gfx@lists.freedesktop.org
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Subject: [Intel-gfx] [PATCH v9 2/3] drm/i915/gem: Add a helper to read data from a GEM object page
Date: Wed, 20 Jan 2021 23:38:34 +0200 [thread overview]
Message-ID: <20210120213834.1435710-1-imre.deak@intel.com> (raw)
In-Reply-To: <20210115194101.1037430-1-imre.deak@intel.com>
Add a simple helper to read data with the CPU from the page of a GEM
object. Do the read either via a kmap if the object has struct pages
or an iomap otherwise. This is needed by the next patch, reading a u64
value from the object (w/o requiring the obj to be mapped to the GPU).
Suggested by Chris.
v2 (Chris):
- Sanitize the type and order of func params.
- Avoid consts requiring too many casts.
- Use BUG_ON instead of WARN_ON, simplify the conditions.
- Fix __iomem sparse errors.
- Leave locking/syncing/pinning up to the caller, require only that the
caller has pinned the object pages.
- Check for iomem backing store before reading via an iomap.
v3:
- Fix offset passed to io_mapping_map_wc() missing a mem.region.start
delta. (Chris, Matthew)
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/gem/i915_gem_object.c | 65 ++++++++++++++++++++++
drivers/gpu/drm/i915/gem/i915_gem_object.h | 8 +++
2 files changed, 73 insertions(+)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.c b/drivers/gpu/drm/i915/gem/i915_gem_object.c
index 83c6ee6a509a..ad90a43a1c8c 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.c
@@ -31,6 +31,7 @@
#include "i915_gem_mman.h"
#include "i915_gem_object.h"
#include "i915_globals.h"
+#include "i915_memcpy.h"
#include "i915_trace.h"
static struct i915_global_object {
@@ -336,6 +337,70 @@ void __i915_gem_object_invalidate_frontbuffer(struct drm_i915_gem_object *obj,
}
}
+static void
+i915_gem_object_read_from_page_kmap(struct drm_i915_gem_object *obj, u64 offset, void *dst, int size)
+{
+ void *src_map;
+ void *src_ptr;
+
+ src_map = kmap_atomic(i915_gem_object_get_page(obj, offset >> PAGE_SHIFT));
+
+ src_ptr = src_map + offset_in_page(offset);
+ if (!(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_READ))
+ drm_clflush_virt_range(src_ptr, size);
+ memcpy(dst, src_ptr, size);
+
+ kunmap_atomic(src_map);
+}
+
+static void
+i915_gem_object_read_from_page_iomap(struct drm_i915_gem_object *obj, u64 offset, void *dst, int size)
+{
+ void __iomem *src_map;
+ void __iomem *src_ptr;
+ dma_addr_t dma = i915_gem_object_get_dma_address(obj, offset >> PAGE_SHIFT);
+
+ src_map = io_mapping_map_wc(&obj->mm.region->iomap,
+ dma - obj->mm.region->region.start,
+ PAGE_SIZE);
+
+ src_ptr = src_map + offset_in_page(offset);
+ if (!i915_memcpy_from_wc(dst, (void __force *)src_ptr, size))
+ memcpy_fromio(dst, src_ptr, size);
+
+ io_mapping_unmap(src_map);
+}
+
+/**
+ * i915_gem_object_read_from_page - read data from the page of a GEM object
+ * @obj: GEM object to read from
+ * @offset: offset within the object
+ * @dst: buffer to store the read data
+ * @size: size to read
+ *
+ * Reads data from @obj at the specified offset. The requested region to read
+ * from can't cross a page boundary. The caller must ensure that @obj pages
+ * are pinned and that @obj is synced wrt. any related writes.
+ *
+ * Returns 0 on sucess or -ENODEV if the type of @obj's backing store is
+ * unsupported.
+ */
+int i915_gem_object_read_from_page(struct drm_i915_gem_object *obj, u64 offset, void *dst, int size)
+{
+ GEM_BUG_ON(offset >= obj->base.size);
+ GEM_BUG_ON(offset_in_page(offset) > PAGE_SIZE - size);
+ GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
+
+ if (i915_gem_object_has_struct_page(obj))
+ i915_gem_object_read_from_page_kmap(obj, offset, dst, size);
+ else if (i915_gem_object_has_iomem(obj))
+ i915_gem_object_read_from_page_iomap(obj, offset, dst, size);
+ else
+ return -ENODEV;
+
+ return 0;
+}
+
void i915_gem_init__objects(struct drm_i915_private *i915)
{
INIT_WORK(&i915->mm.free_work, __i915_gem_free_work);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index b6a16ab85956..bb8aea75c3fd 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -200,6 +200,12 @@ i915_gem_object_has_struct_page(const struct drm_i915_gem_object *obj)
return i915_gem_object_type_has(obj, I915_GEM_OBJECT_HAS_STRUCT_PAGE);
}
+static inline bool
+i915_gem_object_has_iomem(const struct drm_i915_gem_object *obj)
+{
+ return i915_gem_object_type_has(obj, I915_GEM_OBJECT_HAS_IOMEM);
+}
+
static inline bool
i915_gem_object_is_shrinkable(const struct drm_i915_gem_object *obj)
{
@@ -531,4 +537,6 @@ i915_gem_object_invalidate_frontbuffer(struct drm_i915_gem_object *obj,
__i915_gem_object_invalidate_frontbuffer(obj, origin);
}
+int i915_gem_object_read_from_page(struct drm_i915_gem_object *obj, u64 offset, void *dst, int size);
+
#endif
--
2.25.1
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next prev parent reply other threads:[~2021-01-20 21:38 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-14 20:13 [Intel-gfx] [PATCH v7 0/3] drm/i915/gen12: Add display render clear color decompression support Imre Deak
2021-01-14 20:13 ` [Intel-gfx] [PATCH v7 1/3] drm/framebuffer: Format modifier for Intel Gen 12 render compression with Clear Color Imre Deak
2021-01-15 9:41 ` Kahola, Mika
2021-01-15 18:42 ` Chery, Nanley G
2021-01-14 20:13 ` [Intel-gfx] [PATCH v7 2/3] drm/i915/gem: Add a helper to read data from a GEM object page Imre Deak
2021-01-14 21:23 ` Chris Wilson
2021-01-15 17:01 ` Imre Deak
2021-01-15 19:41 ` [Intel-gfx] [PATCH v8 " Imre Deak
2021-01-20 12:02 ` Chris Wilson
2021-01-20 19:43 ` Imre Deak
2021-01-20 21:38 ` Imre Deak [this message]
2021-01-14 20:13 ` [Intel-gfx] [PATCH v7 3/3] drm/i915/tgl: Add Clear Color support for TGL Render Decompression Imre Deak
2021-01-15 19:41 ` [Intel-gfx] [PATCH v8 " Imre Deak
2021-01-15 21:39 ` [Intel-gfx] [PATCH v9 " Imre Deak
2021-01-21 20:48 ` Matt Roper
2021-01-19 8:29 ` [Intel-gfx] [PATCH v7 " Dan Carpenter
2021-01-19 14:20 ` Imre Deak
2021-01-14 21:39 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for drm/i915/gen12: Add display render clear color decompression support Patchwork
2021-01-14 21:42 ` [Intel-gfx] ✗ Fi.CI.SPARSE: " Patchwork
2021-01-14 22:10 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2021-01-15 10:05 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork
2021-01-15 23:14 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for drm/i915/gen12: Add display render clear color decompression support (rev4) Patchwork
2021-01-15 23:16 ` [Intel-gfx] ✗ Fi.CI.SPARSE: " Patchwork
2021-01-15 23:43 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2021-01-16 9:26 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork
2021-01-20 22:52 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for drm/i915/gen12: Add display render clear color decompression support (rev5) Patchwork
2021-01-20 22:55 ` [Intel-gfx] ✗ Fi.CI.SPARSE: " Patchwork
2021-01-20 23:23 ` [Intel-gfx] ✗ Fi.CI.BAT: failure " Patchwork
2021-01-21 12:57 ` Imre Deak
2021-01-21 14:14 ` Saarinen, Jani
2021-01-22 3:33 ` Vudum, Lakshminarayana
2021-01-22 3:32 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2021-01-22 6:50 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork
2021-01-22 14:33 ` Imre Deak
2021-01-22 16:47 ` Vudum, Lakshminarayana
2021-01-22 16:43 ` [Intel-gfx] ✓ Fi.CI.IGT: success " Patchwork
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