drm/vkms: Add dumb operations

VKMS currently does not handle dumb data, and as a consequence, it does
not provide mechanisms for handling gem. This commit adds the necessary
support for gem object/handler and the dumb functions.

Changes since V1:
 Daniel Vetter:
 - Add dumb buffer support to the same patchset
Changes since V2:
 Haneen:
 - Add missing gem_free_object_unlocked callback to fix the warning
   "Memory manager not clean during takedown"

Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/70b7becc91c6a323dbc15cb5fc912cbdfe4ef7d9.1531359228.git.rodrigosiqueiramelo@gmail.com

1 files changed, 179 insertions, 0 deletions

diff --git a/drivers/gpu/drm/vkms/vkms_gem.c b/drivers/gpu/drm/vkms/vkms_gem.c
new file mode 100644
index 000000000000..c7e38368602b
--- /dev/null
+++ b/drivers/gpu/drm/vkms/vkms_gem.c
@@ -0,0 +1,179 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/shmem_fs.h>
+
+#include "vkms_drv.h"
+
+static struct vkms_gem_object *__vkms_gem_create(struct drm_device *dev,
+						 u64 size)
+{
+	struct vkms_gem_object *obj;
+	int ret;
+
+	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
+	if (!obj)
+		return ERR_PTR(-ENOMEM);
+
+	size = roundup(size, PAGE_SIZE);
+	ret = drm_gem_object_init(dev, &obj->gem, size);
+	if (ret) {
+		kfree(obj);
+		return ERR_PTR(ret);
+	}
+
+	mutex_init(&obj->pages_lock);
+
+	return obj;
+}
+
+void vkms_gem_free_object(struct drm_gem_object *obj)
+{
+	struct vkms_gem_object *gem = container_of(obj, struct vkms_gem_object,
+						   gem);
+
+	kvfree(gem->pages);
+	mutex_destroy(&gem->pages_lock);
+	drm_gem_object_release(obj);
+	kfree(gem);
+}
+
+int vkms_gem_fault(struct vm_fault *vmf)
+{
+	struct vm_area_struct *vma = vmf->vma;
+	struct vkms_gem_object *obj = vma->vm_private_data;
+	unsigned long vaddr = vmf->address;
+	pgoff_t page_offset;
+	loff_t num_pages;
+	int ret;
+
+	page_offset = (vaddr - vma->vm_start) >> PAGE_SHIFT;
+	num_pages = DIV_ROUND_UP(obj->gem.size, PAGE_SIZE);
+
+	if (page_offset > num_pages)
+		return VM_FAULT_SIGBUS;
+
+	ret = -ENOENT;
+	mutex_lock(&obj->pages_lock);
+	if (obj->pages) {
+		get_page(obj->pages[page_offset]);
+		vmf->page = obj->pages[page_offset];
+		ret = 0;
+	}
+	mutex_unlock(&obj->pages_lock);
+	if (ret) {
+		struct page *page;
+		struct address_space *mapping;
+
+		mapping = file_inode(obj->gem.filp)->i_mapping;
+		page = shmem_read_mapping_page(mapping, page_offset);
+
+		if (!IS_ERR(page)) {
+			vmf->page = page;
+			ret = 0;
+		} else {
+			switch (PTR_ERR(page)) {
+			case -ENOSPC:
+			case -ENOMEM:
+				ret = VM_FAULT_OOM;
+				break;
+			case -EBUSY:
+				ret = VM_FAULT_RETRY;
+				break;
+			case -EFAULT:
+			case -EINVAL:
+				ret = VM_FAULT_SIGBUS;
+				break;
+			default:
+				WARN_ON(PTR_ERR(page));
+				ret = VM_FAULT_SIGBUS;
+				break;
+			}
+		}
+	}
+	return ret;
+}
+
+struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
+				       struct drm_file *file,
+				       u32 *handle,
+				       u64 size)
+{
+	struct vkms_gem_object *obj;
+	int ret;
+
+	if (!file || !dev || !handle)
+		return ERR_PTR(-EINVAL);
+
+	obj = __vkms_gem_create(dev, size);
+	if (IS_ERR(obj))
+		return ERR_CAST(obj);
+
+	ret = drm_gem_handle_create(file, &obj->gem, handle);
+	drm_gem_object_put_unlocked(&obj->gem);
+	if (ret) {
+		drm_gem_object_release(&obj->gem);
+		kfree(obj);
+		return ERR_PTR(ret);
+	}
+
+	return &obj->gem;
+}
+
+int vkms_dumb_create(struct drm_file *file, struct drm_device *dev,
+		     struct drm_mode_create_dumb *args)
+{
+	struct drm_gem_object *gem_obj;
+	u64 pitch, size;
+
+	if (!args || !dev || !file)
+		return -EINVAL;
+
+	pitch = args->width * DIV_ROUND_UP(args->bpp, 8);
+	size = pitch * args->height;
+
+	if (!size)
+		return -EINVAL;
+
+	gem_obj = vkms_gem_create(dev, file, &args->handle, size);
+	if (IS_ERR(gem_obj))
+		return PTR_ERR(gem_obj);
+
+	args->size = gem_obj->size;
+	args->pitch = pitch;
+
+	DRM_DEBUG_DRIVER("Created object of size %lld\n", size);
+
+	return 0;
+}
+
+int vkms_dumb_map(struct drm_file *file, struct drm_device *dev,
+		  u32 handle, u64 *offset)
+{
+	struct drm_gem_object *obj;
+	int ret;
+
+	obj = drm_gem_object_lookup(file, handle);
+	if (!obj)
+		return -ENOENT;
+
+	if (!obj->filp) {
+		ret = -EINVAL;
+		goto unref;
+	}
+
+	ret = drm_gem_create_mmap_offset(obj);
+	if (ret)
+		goto unref;
+
+	*offset = drm_vma_node_offset_addr(&obj->vma_node);
+unref:
+	drm_gem_object_put_unlocked(obj);
+
+	return ret;
+}