drm/panthor: Add GEM logical block

Anything relating to GEM object management is placed here. Nothing
particularly interesting here, given the implementation is based on
drm_gem_shmem_object, which is doing most of the work.

v6:
- Add Maxime's and Heiko's acks
- Return a page-aligned BO size to userspace when creating a BO
- Keep header inclusion alphabetically ordered

v5:
- Add Liviu's and Steve's R-b

v4:
- Force kernel BOs to be GPU mapped
- Make panthor_kernel_bo_destroy() robust against ERR/NULL BO pointers
  to simplify the call sites

v3:
- Add acks for the MIT/GPL2 relicensing
- Provide a panthor_kernel_bo abstraction for buffer objects managed by
  the kernel (will replace panthor_fw_mem and be used everywhere we were
  using panthor_gem_create_and_map() before)
- Adjust things to match drm_gpuvm changes
- Change return of panthor_gem_create_with_handle() to int

Co-developed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Acked-by: Steven Price <steven.price@arm.com> # MIT+GPL2 relicensing,Arm
Acked-by: Grant Likely <grant.likely@linaro.org> # MIT+GPL2 relicensing,Linaro
Acked-by: Boris Brezillon <boris.brezillon@collabora.com> # MIT+GPL2 relicensing,Collabora
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20240229162230.2634044-6-boris.brezillon@collabora.com

1 files changed, 142 insertions, 0 deletions

diff --git a/drivers/gpu/drm/panthor/panthor_gem.h b/drivers/gpu/drm/panthor/panthor_gem.h
new file mode 100644
index 000000000000..3bccba394d00
--- /dev/null
+++ b/drivers/gpu/drm/panthor/panthor_gem.h
@@ -0,0 +1,142 @@
+/* SPDX-License-Identifier: GPL-2.0 or MIT */
+/* Copyright 2019 Linaro, Ltd, Rob Herring <robh@kernel.org> */
+/* Copyright 2023 Collabora ltd. */
+
+#ifndef __PANTHOR_GEM_H__
+#define __PANTHOR_GEM_H__
+
+#include <drm/drm_gem_shmem_helper.h>
+#include <drm/drm_mm.h>
+
+#include <linux/iosys-map.h>
+#include <linux/rwsem.h>
+
+struct panthor_vm;
+
+/**
+ * struct panthor_gem_object - Driver specific GEM object.
+ */
+struct panthor_gem_object {
+	/** @base: Inherit from drm_gem_shmem_object. */
+	struct drm_gem_shmem_object base;
+
+	/**
+	 * @exclusive_vm_root_gem: Root GEM of the exclusive VM this GEM object
+	 * is attached to.
+	 *
+	 * If @exclusive_vm_root_gem != NULL, any attempt to bind the GEM to a
+	 * different VM will fail.
+	 *
+	 * All FW memory objects have this field set to the root GEM of the MCU
+	 * VM.
+	 */
+	struct drm_gem_object *exclusive_vm_root_gem;
+
+	/**
+	 * @gpuva_list_lock: Custom GPUVA lock.
+	 *
+	 * Used to protect insertion of drm_gpuva elements to the
+	 * drm_gem_object.gpuva.list list.
+	 *
+	 * We can't use the GEM resv for that, because drm_gpuva_link() is
+	 * called in a dma-signaling path, where we're not allowed to take
+	 * resv locks.
+	 */
+	struct mutex gpuva_list_lock;
+
+	/** @flags: Combination of drm_panthor_bo_flags flags. */
+	u32 flags;
+};
+
+/**
+ * struct panthor_kernel_bo - Kernel buffer object.
+ *
+ * These objects are only manipulated by the kernel driver and not
+ * directly exposed to the userspace. The GPU address of a kernel
+ * BO might be passed to userspace though.
+ */
+struct panthor_kernel_bo {
+	/**
+	 * @obj: The GEM object backing this kernel buffer object.
+	 */
+	struct drm_gem_object *obj;
+
+	/**
+	 * @va_node: VA space allocated to this GEM.
+	 */
+	struct drm_mm_node va_node;
+
+	/**
+	 * @kmap: Kernel CPU mapping of @gem.
+	 */
+	void *kmap;
+};
+
+static inline
+struct panthor_gem_object *to_panthor_bo(struct drm_gem_object *obj)
+{
+	return container_of(to_drm_gem_shmem_obj(obj), struct panthor_gem_object, base);
+}
+
+struct drm_gem_object *panthor_gem_create_object(struct drm_device *ddev, size_t size);
+
+struct drm_gem_object *
+panthor_gem_prime_import_sg_table(struct drm_device *ddev,
+				  struct dma_buf_attachment *attach,
+				  struct sg_table *sgt);
+
+int
+panthor_gem_create_with_handle(struct drm_file *file,
+			       struct drm_device *ddev,
+			       struct panthor_vm *exclusive_vm,
+			       u64 *size, u32 flags, uint32_t *handle);
+
+static inline u64
+panthor_kernel_bo_gpuva(struct panthor_kernel_bo *bo)
+{
+	return bo->va_node.start;
+}
+
+static inline size_t
+panthor_kernel_bo_size(struct panthor_kernel_bo *bo)
+{
+	return bo->obj->size;
+}
+
+static inline int
+panthor_kernel_bo_vmap(struct panthor_kernel_bo *bo)
+{
+	struct iosys_map map;
+	int ret;
+
+	if (bo->kmap)
+		return 0;
+
+	ret = drm_gem_vmap_unlocked(bo->obj, &map);
+	if (ret)
+		return ret;
+
+	bo->kmap = map.vaddr;
+	return 0;
+}
+
+static inline void
+panthor_kernel_bo_vunmap(struct panthor_kernel_bo *bo)
+{
+	if (bo->kmap) {
+		struct iosys_map map = IOSYS_MAP_INIT_VADDR(bo->kmap);
+
+		drm_gem_vunmap_unlocked(bo->obj, &map);
+		bo->kmap = NULL;
+	}
+}
+
+struct panthor_kernel_bo *
+panthor_kernel_bo_create(struct panthor_device *ptdev, struct panthor_vm *vm,
+			 size_t size, u32 bo_flags, u32 vm_map_flags,
+			 u64 gpu_va);
+
+void panthor_kernel_bo_destroy(struct panthor_vm *vm,
+			       struct panthor_kernel_bo *bo);
+
+#endif /* __PANTHOR_GEM_H__ */