On 09/08/2023 17:53, Boris Brezillon wrote:
> 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.
>
> v2:
> - Rename the driver (pancsf -> panthor)
> - Change the license (GPL2 -> MIT + GPL2)
> - Split the driver addition commit
> - Document the code
>
> Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
One minor comment below, but otherwise:
Reviewed-by: Steven Price <steven.price@xxxxxxx>
> ---
> drivers/gpu/drm/panthor/panthor_gem.c | 229 ++++++++++++++++++++++++++
> drivers/gpu/drm/panthor/panthor_gem.h | 96 +++++++++++
> 2 files changed, 325 insertions(+)
> create mode 100644 drivers/gpu/drm/panthor/panthor_gem.c
> create mode 100644 drivers/gpu/drm/panthor/panthor_gem.h
>
> diff --git a/drivers/gpu/drm/panthor/panthor_gem.c b/drivers/gpu/drm/panthor/panthor_gem.c
> new file mode 100644
> index 000000000000..a441a68822ca
> --- /dev/null
> +++ b/drivers/gpu/drm/panthor/panthor_gem.c
> @@ -0,0 +1,229 @@
> +// SPDX-License-Identifier: GPL-2.0 or MIT
> +/* Copyright 2019 Linaro, Ltd, Rob Herring <robh@xxxxxxxxxx> */
> +/* Copyright 2023 Collabora ltd. */
> +
> +#include <linux/err.h>
> +#include <linux/slab.h>
> +#include <linux/dma-buf.h>
> +#include <linux/dma-mapping.h>
> +
> +#include <drm/panthor_drm.h>
> +
> +#include "panthor_device.h"
> +#include "panthor_gem.h"
> +#include "panthor_mmu.h"
> +
> +static void panthor_gem_free_object(struct drm_gem_object *obj)
> +{
> + struct panthor_gem_object *bo = to_panthor_bo(obj);
> +
> + if (drm_WARN_ON(obj->dev, bo->va_node))
> + panthor_vm_free_va(bo->exclusive_vm, bo->va_node);
> +
> + panthor_vm_put(bo->exclusive_vm);
> + drm_gem_free_mmap_offset(&bo->base.base);
> + mutex_destroy(&bo->gpuva_list_lock);
> + drm_gem_shmem_free(&bo->base);
> +}
> +
> +/**
> + * panthor_gem_unmap_and_put() - Unmap and drop the reference on a GEM object
> + * @vm: VM to unmap the GEM from.
> + * @bo: GEM object to unmap/release.
> + * @gpu_va: GPU/MCU virtual address the GEM object was mapped at.
> + * @cpu_va: kernel mapping of the GEM object.
> + * Can be NULL if the GEM was not CPU mapped.
> + *
> + * Should be called to undo what was done in panthor_gem_create_and_map().
> + */
> +void panthor_gem_unmap_and_put(struct panthor_vm *vm,
> + struct panthor_gem_object *bo,
> + u64 gpu_va, void *cpu_va)
> +{
> + if (cpu_va) {
> + struct iosys_map map = IOSYS_MAP_INIT_VADDR(cpu_va);
> +
> + drm_gem_vunmap_unlocked(&bo->base.base, &map);
> + }
> +
> + drm_WARN_ON(bo->base.base.dev, panthor_vm_unmap_range(vm, gpu_va, bo->base.base.size));
> + panthor_vm_free_va(vm, bo->va_node);
> + bo->va_node = NULL;
> + drm_gem_object_put(&bo->base.base);
> +}
> +
> +/**
> + * panthor_gem_create_and_map() - Create and map a GEM object to a VM
> + * @ptdev: Device.
> + * @vm: VM to map the GEM to.
> + * @bo_flags: Combination of drm_panthor_bo_flags flags.
> + * @vm_map_flags: Combination of drm_panthor_vm_bind_op_flags (only those
> + * that are related to map operations).
> + * @gpu_va: Pointer holding the GPU address assigned when mapping to the VM.
> + * If *gpu_va == PANTHOR_GEM_ALLOC_VA, a virtual address range will be allocated
> + * and the allocated address returned, otherwise *gpu_va is used directly.
> + * @cpu_va: Pointer holding the kernel CPU mapping. If NULL, the GEM object
> + * is not CPU-mapped.
> + *
> + * Return: A valid pointer in case of success, an ERR_PTR() otherwise.
> + */
> +struct panthor_gem_object *
> +panthor_gem_create_and_map(struct panthor_device *ptdev, struct panthor_vm *vm,
> + size_t size, u32 bo_flags, u32 vm_map_flags,
> + u64 *gpu_va, void **cpu_va)
> +{
> + struct drm_gem_shmem_object *obj;
> + struct panthor_gem_object *bo;
> + int ret;
> +
> + obj = drm_gem_shmem_create(&ptdev->base, size);
> + if (!obj)
> + return ERR_PTR(-ENOMEM);
> +
> + bo = to_panthor_bo(&obj->base);
> + bo->flags = bo_flags;
> + bo->exclusive_vm = panthor_vm_get(vm);
> + bo->base.base.resv = panthor_vm_resv(vm);
> +
> + if (*gpu_va == PANTHOR_GEM_ALLOC_VA) {
> + bo->va_node = panthor_vm_alloc_va(vm, obj->base.size);
> +
> + if (IS_ERR(bo->va_node)) {
> + ret = PTR_ERR(bo->va_node);
> + bo->va_node = NULL;
> + goto err_put_obj;
> + }
> +
> + *gpu_va = bo->va_node->start;
> + }
> +
> + ret = panthor_vm_map_bo_range(vm, bo, 0, obj->base.size, *gpu_va, vm_map_flags);
> + if (ret)
> + goto err_put_obj;
> +
> + if (cpu_va) {
> + struct iosys_map map;
> + int ret;
> +
> + ret = drm_gem_vmap_unlocked(&obj->base, &map);
> + if (ret)
> + goto err_vm_unmap_range;
> +
> + *cpu_va = map.vaddr;
> + }
> +
> + return bo;
> +
> +err_vm_unmap_range:
> + panthor_vm_unmap_range(vm, *gpu_va, obj->base.size);
> +
> +err_put_obj:
> + drm_gem_object_put(&obj->base);
> + return ERR_PTR(ret);
> +}
> +
> +static int panthor_gem_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
> +{
> + struct panthor_gem_object *bo = to_panthor_bo(obj);
> +
> + /* Don't allow mmap on objects that have the NO_MMAP flag set. */
> + if (bo->flags & DRM_PANTHOR_BO_NO_MMAP)
> + return -EINVAL;
> +
> + return drm_gem_shmem_object_mmap(obj, vma);
> +}
> +
> +static struct dma_buf *
> +panthor_gem_prime_export(struct drm_gem_object *obj, int flags)
> +{
> + /* We can't export GEMs that have an exclusive VM. */
> + if (to_panthor_bo(obj)->exclusive_vm)
> + return ERR_PTR(-EINVAL);
> +
> + return drm_gem_prime_export(obj, flags);
> +}
> +
> +static const struct drm_gem_object_funcs panthor_gem_funcs = {
> + .free = panthor_gem_free_object,
> + .print_info = drm_gem_shmem_object_print_info,
> + .pin = drm_gem_shmem_object_pin,
> + .unpin = drm_gem_shmem_object_unpin,
> + .get_sg_table = drm_gem_shmem_object_get_sg_table,
> + .vmap = drm_gem_shmem_object_vmap,
> + .vunmap = drm_gem_shmem_object_vunmap,
> + .mmap = panthor_gem_mmap,
> + .export = panthor_gem_prime_export,
> + .vm_ops = &drm_gem_shmem_vm_ops,
> +};
> +
> +/**
> + * panthor_gem_create_object - Implementation of driver->gem_create_object.
> + * @dev: DRM device
> + * @size: Size in bytes of the memory the object will reference
> + *
> + * This lets the GEM helpers allocate object structs for us, and keep
> + * our BO stats correct.
> + */
> +struct drm_gem_object *panthor_gem_create_object(struct drm_device *ddev, size_t size)
> +{
> + struct panthor_device *ptdev = container_of(ddev, struct panthor_device, base);
> + struct panthor_gem_object *obj;
> +
> + obj = kzalloc(sizeof(*obj), GFP_KERNEL);
> + if (!obj)
> + return ERR_PTR(-ENOMEM);
> +
> + obj->base.base.funcs = &panthor_gem_funcs;
> + obj->base.map_wc = !ptdev->coherent;
> + mutex_init(&obj->gpuva_list_lock);
> + drm_gem_gpuva_set_lock(&obj->base.base, &obj->gpuva_list_lock);
> +
> + return &obj->base.base;
> +}
> +
> +/**
> + * panthor_gem_create_with_handle() - Create a GEM object and attach it to a handle.
> + * @file: DRM file.
> + * @ddev: DRM device.
> + * @exclusive_vm: Exclusive VM. Not NULL if the GEM object can't be shared.
> + * @size: Size of the GEM object to allocate.
> + * @flags: Combination of drm_panthor_bo_flags flags.
> + * @handle: Pointer holding the handle pointing to the new GEM object.
> + *
> + * Return: A valid pointer on success, an ERR_PTR() otherwise.
> + */
> +struct panthor_gem_object *
> +panthor_gem_create_with_handle(struct drm_file *file,
> + struct drm_device *ddev,
> + struct panthor_vm *exclusive_vm,
> + size_t size,
> + u32 flags, u32 *handle)
> +{
> + int ret;
> + struct drm_gem_shmem_object *shmem;
> + struct panthor_gem_object *bo;
> +
> + shmem = drm_gem_shmem_create(ddev, size);
> + if (IS_ERR(shmem))
> + return ERR_CAST(shmem);
> +
> + bo = to_panthor_bo(&shmem->base);
> + bo->flags = flags;
> +
> + if (exclusive_vm) {
> + bo->exclusive_vm = panthor_vm_get(exclusive_vm);
> + bo->base.base.resv = panthor_vm_resv(exclusive_vm);
> + }
> +
> + /*
> + * Allocate an id of idr table where the obj is registered
> + * and handle has the id what user can see.
> + */
> + ret = drm_gem_handle_create(file, &shmem->base, handle);
> + /* drop reference from allocate - handle holds it now. */
> + drm_gem_object_put(&shmem->base);
> + if (ret)
> + return ERR_PTR(ret);
> +
> + return bo;
> +}
This function might be better just returning a simple int. The
"with_handle" approach means that doing anything much with the returned
object is dodgy (because another user space thread could have already
guessed the handle), and anyway the only caller
(panthor_ioctl_bo_create()) doesn't use the object and just extracts the
error code (if any).
Steve
> diff --git a/drivers/gpu/drm/panthor/panthor_gem.h b/drivers/gpu/drm/panthor/panthor_gem.h
> new file mode 100644
> index 000000000000..07babadc7623
> --- /dev/null
> +++ b/drivers/gpu/drm/panthor/panthor_gem.h
> @@ -0,0 +1,96 @@
> +/* SPDX-License-Identifier: GPL-2.0 or MIT */
> +/* Copyright 2019 Linaro, Ltd, Rob Herring <robh@xxxxxxxxxx> */
> +/* 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/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;
> +
> + /**
> + * @va_node: VA space allocated to this GEM.
> + *
> + * Should be NULL for all GEM objects managed by userspace.
> + *
> + * Not NULL when %PANTHOR_GEM_ALLOC_VA is passed as an address, in
> + * which case the GEM logic will auto-allocate a VA range before mapping
> + * to the VM.
> + *
> + * @exclusive_vm must be != NULL.
> + */
> + struct drm_mm_node *va_node;
> +
> + /**
> + * @exclusive_vm: Exclusive VM this GEM object can be mapped to.
> + *
> + * If @exclusive_vm != NULL, any attempt to bind the GEM to a different
> + * VM will fail.
> + *
> + * All FW memory objects have this field set to the MCU VM.
> + */
> + struct panthor_vm *exclusive_vm;
> +
> + /**
> + * @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;
> +};
> +
> +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);
> +
> +struct panthor_gem_object *
> +panthor_gem_create_with_handle(struct drm_file *file,
> + struct drm_device *ddev,
> + struct panthor_vm *exclusive_vm,
> + size_t size,
> + u32 flags,
> + uint32_t *handle);
> +
> +void panthor_gem_unmap_and_put(struct panthor_vm *vm, struct panthor_gem_object *bo,
> + u64 gpu_va, void *cpu_va);
> +
> +/*
> + * PANTHOR_GEM_ALLOC_VA: Use this magic address when you want the GEM
> + * logic to auto-allocate the virtual address in the reserved kernel VA range.
> + */
> +#define PANTHOR_GEM_ALLOC_VA ~0ull
> +
> +struct panthor_gem_object *
> +panthor_gem_create_and_map(struct panthor_device *ptdev, struct panthor_vm *vm,
> + size_t size, u32 bo_flags, u32 vm_map_flags,
> + u64 *gpu_va, void **cpu_va);
> +
> +#endif /* __PANTHOR_GEM_H__ */
