1 files changed, 297 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_vram_mm_helper.c b/drivers/gpu/drm/drm_vram_mm_helper.c
new file mode 100644
index 000000000000..c911781d6728
--- /dev/null
+++ b/drivers/gpu/drm/drm_vram_mm_helper.c
@@ -0,0 +1,297 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <drm/drm_device.h>
+#include <drm/drm_file.h>
+#include <drm/drm_vram_mm_helper.h>
+
+#include <drm/ttm/ttm_page_alloc.h>
+
+/**
+ * DOC: overview
+ *
+ * The data structure &struct drm_vram_mm and its helpers implement a memory
+ * manager for simple framebuffer devices with dedicated video memory. Buffer
+ * objects are either placed in video RAM or evicted to system memory. These
+ * helper functions work well with &struct drm_gem_vram_object.
+ */
+
+/*
+ * TTM TT
+ */
+
+static void backend_func_destroy(struct ttm_tt *tt)
+{
+	ttm_tt_fini(tt);
+	kfree(tt);
+}
+
+static struct ttm_backend_func backend_func = {
+	.destroy = backend_func_destroy
+};
+
+/*
+ * TTM BO device
+ */
+
+static struct ttm_tt *bo_driver_ttm_tt_create(struct ttm_buffer_object *bo,
+					      uint32_t page_flags)
+{
+	struct ttm_tt *tt;
+	int ret;
+
+	tt = kzalloc(sizeof(*tt), GFP_KERNEL);
+	if (!tt)
+		return NULL;
+
+	tt->func = &backend_func;
+
+	ret = ttm_tt_init(tt, bo, page_flags);
+	if (ret < 0)
+		goto err_ttm_tt_init;
+
+	return tt;
+
+err_ttm_tt_init:
+	kfree(tt);
+	return NULL;
+}
+
+static int bo_driver_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
+				   struct ttm_mem_type_manager *man)
+{
+	switch (type) {
+	case TTM_PL_SYSTEM:
+		man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
+		man->available_caching = TTM_PL_MASK_CACHING;
+		man->default_caching = TTM_PL_FLAG_CACHED;
+		break;
+	case TTM_PL_VRAM:
+		man->func = &ttm_bo_manager_func;
+		man->flags = TTM_MEMTYPE_FLAG_FIXED |
+			     TTM_MEMTYPE_FLAG_MAPPABLE;
+		man->available_caching = TTM_PL_FLAG_UNCACHED |
+					 TTM_PL_FLAG_WC;
+		man->default_caching = TTM_PL_FLAG_WC;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static void bo_driver_evict_flags(struct ttm_buffer_object *bo,
+				  struct ttm_placement *placement)
+{
+	struct drm_vram_mm *vmm = drm_vram_mm_of_bdev(bo->bdev);
+
+	if (vmm->funcs && vmm->funcs->evict_flags)
+		vmm->funcs->evict_flags(bo, placement);
+}
+
+static int bo_driver_verify_access(struct ttm_buffer_object *bo,
+				   struct file *filp)
+{
+	struct drm_vram_mm *vmm = drm_vram_mm_of_bdev(bo->bdev);
+
+	if (!vmm->funcs || !vmm->funcs->verify_access)
+		return 0;
+	return vmm->funcs->verify_access(bo, filp);
+}
+
+static int bo_driver_io_mem_reserve(struct ttm_bo_device *bdev,
+				    struct ttm_mem_reg *mem)
+{
+	struct ttm_mem_type_manager *man = bdev->man + mem->mem_type;
+	struct drm_vram_mm *vmm = drm_vram_mm_of_bdev(bdev);
+
+	if (!(man->flags & TTM_MEMTYPE_FLAG_MAPPABLE))
+		return -EINVAL;
+
+	mem->bus.addr = NULL;
+	mem->bus.size = mem->num_pages << PAGE_SHIFT;
+
+	switch (mem->mem_type) {
+	case TTM_PL_SYSTEM:	/* nothing to do */
+		mem->bus.offset = 0;
+		mem->bus.base = 0;
+		mem->bus.is_iomem = false;
+		break;
+	case TTM_PL_VRAM:
+		mem->bus.offset = mem->start << PAGE_SHIFT;
+		mem->bus.base = vmm->vram_base;
+		mem->bus.is_iomem = true;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void bo_driver_io_mem_free(struct ttm_bo_device *bdev,
+				  struct ttm_mem_reg *mem)
+{ }
+
+static struct ttm_bo_driver bo_driver = {
+	.ttm_tt_create = bo_driver_ttm_tt_create,
+	.ttm_tt_populate = ttm_pool_populate,
+	.ttm_tt_unpopulate = ttm_pool_unpopulate,
+	.init_mem_type = bo_driver_init_mem_type,
+	.eviction_valuable = ttm_bo_eviction_valuable,
+	.evict_flags = bo_driver_evict_flags,
+	.verify_access = bo_driver_verify_access,
+	.io_mem_reserve = bo_driver_io_mem_reserve,
+	.io_mem_free = bo_driver_io_mem_free,
+};
+
+/*
+ * struct drm_vram_mm
+ */
+
+/**
+ * drm_vram_mm_init() - Initialize an instance of VRAM MM.
+ * @vmm:	the VRAM MM instance to initialize
+ * @dev:	the DRM device
+ * @vram_base:	the base address of the video memory
+ * @vram_size:	the size of the video memory in bytes
+ * @funcs:	callback functions for buffer objects
+ *
+ * Returns:
+ * 0 on success, or
+ * a negative error code otherwise.
+ */
+int drm_vram_mm_init(struct drm_vram_mm *vmm, struct drm_device *dev,
+		     uint64_t vram_base, size_t vram_size,
+		     const struct drm_vram_mm_funcs *funcs)
+{
+	int ret;
+
+	vmm->vram_base = vram_base;
+	vmm->vram_size = vram_size;
+	vmm->funcs = funcs;
+
+	ret = ttm_bo_device_init(&vmm->bdev, &bo_driver,
+				 dev->anon_inode->i_mapping,
+				 true);
+	if (ret)
+		return ret;
+
+	ret = ttm_bo_init_mm(&vmm->bdev, TTM_PL_VRAM, vram_size >> PAGE_SHIFT);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_vram_mm_init);
+
+/**
+ * drm_vram_mm_cleanup() - Cleans up an initialized instance of VRAM MM.
+ * @vmm:	the VRAM MM instance to clean up
+ */
+void drm_vram_mm_cleanup(struct drm_vram_mm *vmm)
+{
+	ttm_bo_device_release(&vmm->bdev);
+}
+EXPORT_SYMBOL(drm_vram_mm_cleanup);
+
+/**
+ * drm_vram_mm_mmap() - Helper for implementing &struct file_operations.mmap()
+ * @filp:	the mapping's file structure
+ * @vma:	the mapping's memory area
+ * @vmm:	the VRAM MM instance
+ *
+ * Returns:
+ * 0 on success, or
+ * a negative error code otherwise.
+ */
+int drm_vram_mm_mmap(struct file *filp, struct vm_area_struct *vma,
+		     struct drm_vram_mm *vmm)
+{
+	return ttm_bo_mmap(filp, vma, &vmm->bdev);
+}
+EXPORT_SYMBOL(drm_vram_mm_mmap);
+
+/*
+ * Helpers for integration with struct drm_device
+ */
+
+/**
+ * drm_vram_helper_alloc_mm - Allocates a device's instance of \
+	&struct drm_vram_mm
+ * @dev:	the DRM device
+ * @vram_base:	the base address of the video memory
+ * @vram_size:	the size of the video memory in bytes
+ * @funcs:	callback functions for buffer objects
+ *
+ * Returns:
+ * The new instance of &struct drm_vram_mm on success, or
+ * an ERR_PTR()-encoded errno code otherwise.
+ */
+struct drm_vram_mm *drm_vram_helper_alloc_mm(
+	struct drm_device *dev, uint64_t vram_base, size_t vram_size,
+	const struct drm_vram_mm_funcs *funcs)
+{
+	int ret;
+
+	if (WARN_ON(dev->vram_mm))
+		return dev->vram_mm;
+
+	dev->vram_mm = kzalloc(sizeof(*dev->vram_mm), GFP_KERNEL);
+	if (!dev->vram_mm)
+		return ERR_PTR(-ENOMEM);
+
+	ret = drm_vram_mm_init(dev->vram_mm, dev, vram_base, vram_size, funcs);
+	if (ret)
+		goto err_kfree;
+
+	return dev->vram_mm;
+
+err_kfree:
+	kfree(dev->vram_mm);
+	dev->vram_mm = NULL;
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(drm_vram_helper_alloc_mm);
+
+/**
+ * drm_vram_helper_release_mm - Releases a device's instance of \
+	&struct drm_vram_mm
+ * @dev:	the DRM device
+ */
+void drm_vram_helper_release_mm(struct drm_device *dev)
+{
+	if (!dev->vram_mm)
+		return;
+
+	drm_vram_mm_cleanup(dev->vram_mm);
+	kfree(dev->vram_mm);
+	dev->vram_mm = NULL;
+}
+EXPORT_SYMBOL(drm_vram_helper_release_mm);
+
+/*
+ * Helpers for &struct file_operations
+ */
+
+/**
+ * drm_vram_mm_file_operations_mmap() - \
+	Implements &struct file_operations.mmap()
+ * @filp:	the mapping's file structure
+ * @vma:	the mapping's memory area
+ *
+ * Returns:
+ * 0 on success, or
+ * a negative error code otherwise.
+ */
+int drm_vram_mm_file_operations_mmap(
+	struct file *filp, struct vm_area_struct *vma)
+{
+	struct drm_file *file_priv = filp->private_data;
+	struct drm_device *dev = file_priv->minor->dev;
+
+	if (WARN_ONCE(!dev->vram_mm, "VRAM MM not initialized"))
+		return -EINVAL;
+
+	return drm_vram_mm_mmap(filp, vma, dev->vram_mm);
+}
+EXPORT_SYMBOL(drm_vram_mm_file_operations_mmap);