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From:   Paul Cercueil <paul@crapouillou.net>
To:     David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>
Cc:     od@zcrc.me, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, Paul Cercueil <paul@crapouillou.net>
Subject: [PATCH 1/5] drm: Add and export function drm_gem_cma_create_noncoherent
Date:   Mon,  2 Nov 2020 22:06:47 +0000
Message-Id: <20201102220651.22069-2-paul@crapouillou.net>
In-Reply-To: <20201102220651.22069-1-paul@crapouillou.net>
References: <20201102220651.22069-1-paul@crapouillou.net>
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This function can be used by drivers that need to create a GEM object
with non-coherent backing memory.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
 drivers/gpu/drm/drm_gem_cma_helper.c | 71 +++++++++++++++++++++-------
 include/drm/drm_gem_cma_helper.h     |  2 +
 2 files changed, 56 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
index 2165633c9b9e..717871d741fb 100644
--- a/drivers/gpu/drm/drm_gem_cma_helper.c
+++ b/drivers/gpu/drm/drm_gem_cma_helper.c
@@ -77,21 +77,10 @@ __drm_gem_cma_create(struct drm_device *drm, size_t size)
 	return ERR_PTR(ret);
 }
 
-/**
- * drm_gem_cma_create - allocate an object with the given size
- * @drm: DRM device
- * @size: size of the object to allocate
- *
- * This function creates a CMA GEM object and allocates a contiguous chunk of
- * memory as backing store. The backing memory has the writecombine attribute
- * set.
- *
- * Returns:
- * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
- * error code on failure.
- */
-struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
-					      size_t size)
+static struct drm_gem_cma_object *
+drm_gem_cma_create_with_cache_param(struct drm_device *drm,
+				    size_t size,
+				    bool noncoherent)
 {
 	struct drm_gem_cma_object *cma_obj;
 	int ret;
@@ -102,8 +91,16 @@ struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
 	if (IS_ERR(cma_obj))
 		return cma_obj;
 
-	cma_obj->vaddr = dma_alloc_wc(drm->dev, size, &cma_obj->paddr,
-				      GFP_KERNEL | __GFP_NOWARN);
+	if (noncoherent) {
+		cma_obj->vaddr = dma_alloc_noncoherent(drm->dev, size,
+						       &cma_obj->paddr,
+						       DMA_TO_DEVICE,
+						       GFP_KERNEL | __GFP_NOWARN);
+
+	} else {
+		cma_obj->vaddr = dma_alloc_wc(drm->dev, size, &cma_obj->paddr,
+					      GFP_KERNEL | __GFP_NOWARN);
+	}
 	if (!cma_obj->vaddr) {
 		drm_dbg(drm, "failed to allocate buffer with size %zu\n",
 			 size);
@@ -117,8 +114,48 @@ struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
 	drm_gem_object_put(&cma_obj->base);
 	return ERR_PTR(ret);
 }
+
+/**
+ * drm_gem_cma_create - allocate an object with the given size
+ * @drm: DRM device
+ * @size: size of the object to allocate
+ *
+ * This function creates a CMA GEM object and allocates a contiguous chunk of
+ * memory as backing store. The backing memory has the writecombine attribute
+ * set.
+ *
+ * Returns:
+ * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
+ * error code on failure.
+ */
+struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
+					      size_t size)
+{
+	return drm_gem_cma_create_with_cache_param(drm, size, false);
+}
 EXPORT_SYMBOL_GPL(drm_gem_cma_create);
 
+/**
+ * drm_gem_cma_create_noncoherent - allocate an object with the given size
+ *     and non-coherent cache attribute
+ * @drm: DRM device
+ * @size: size of the object to allocate
+ *
+ * This function creates a CMA GEM object and allocates a contiguous chunk of
+ * memory as backing store. The backing memory has the noncoherent attribute
+ * set.
+ *
+ * Returns:
+ * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
+ * error code on failure.
+ */
+struct drm_gem_cma_object *
+drm_gem_cma_create_noncoherent(struct drm_device *drm, size_t size)
+{
+	return drm_gem_cma_create_with_cache_param(drm, size, true);
+}
+EXPORT_SYMBOL_GPL(drm_gem_cma_create_noncoherent);
+
 /**
  * drm_gem_cma_create_with_handle - allocate an object with the given size and
  *     return a GEM handle to it
diff --git a/include/drm/drm_gem_cma_helper.h b/include/drm/drm_gem_cma_helper.h
index 2bfa2502607a..071c73ad7177 100644
--- a/include/drm/drm_gem_cma_helper.h
+++ b/include/drm/drm_gem_cma_helper.h
@@ -82,6 +82,8 @@ int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma);
 /* allocate physical memory */
 struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
 					      size_t size);
+struct drm_gem_cma_object *
+drm_gem_cma_create_noncoherent(struct drm_device *drm, size_t size);
 
 extern const struct vm_operations_struct drm_gem_cma_vm_ops;
 
-- 
2.28.0