Commit e06177ec authored by Boris Brezillon's avatar Boris Brezillon
Browse files

drm/panthor: Add a PANTHOR_BO_SYNC ioctl 



This will be used by the UMD to synchronize CPU-cached mappings when
the UMD can't do it directly (no usermode cache maintenance instruction
on Arm32).

v2:
- Change the flags so they better match the drm_gem_shmem_sync()
  semantics

v3:
- Add Steve's R-b

v4:
- No changes

v5:
- Drop Steve's R-b (the semantics changes call for a new review)

v6:
- Drop ret initialization in panthor_ioctl_bo_sync()
- Bail out early in panthor_ioctl_bo_sync() if ops.count is zero
- Drop unused PANTHOR_BO_SYNC_OP_FLAGS definition

v7:
- Hand-roll the sync logic (was previously provided by gem_shmem)

v8:
- Collect R-b

Signed-off-by: default avatarFaith Ekstrand <faith.ekstrand@collabora.com>
Reviewed-by: default avatarSteven Price <steven.price@arm.com>
Link: https://patch.msgid.link/20251208100841.730527-5-boris.brezillon@collabora.com


Signed-off-by: default avatarBoris Brezillon <boris.brezillon@collabora.com>
parent ea78ec98

drivers/gpu/drm/panthor/panthor_drv.c

+40 −1
Original line number Diff line number Diff line
@@ -177,7 +177,8 @@ panthor_get_uobj_array(const struct drm_panthor_obj_array *in, u32 min_stride, 
		 PANTHOR_UOBJ_DECL(struct drm_panthor_sync_op, timeline_value), \

		 PANTHOR_UOBJ_DECL(struct drm_panthor_queue_submit, syncs), \

		 PANTHOR_UOBJ_DECL(struct drm_panthor_queue_create, ringbuf_size), \

		 PANTHOR_UOBJ_DECL(struct drm_panthor_vm_bind_op, syncs))

		 PANTHOR_UOBJ_DECL(struct drm_panthor_vm_bind_op, syncs), \

		 PANTHOR_UOBJ_DECL(struct drm_panthor_bo_sync_op, size))



/**

 * PANTHOR_UOBJ_SET() - Copy a kernel object to a user object.
@@ -1396,6 +1397,43 @@ static int panthor_ioctl_set_user_mmio_offset(struct drm_device *ddev, 
	return 0;

}



static int panthor_ioctl_bo_sync(struct drm_device *ddev, void *data,

				 struct drm_file *file)

{

	struct drm_panthor_bo_sync *args = data;

	struct drm_panthor_bo_sync_op *ops;

	struct drm_gem_object *obj;

	int ret;



	if (!args->ops.count)

		return 0;



	ret = PANTHOR_UOBJ_GET_ARRAY(ops, &args->ops);

	if (ret)

		return ret;



	for (u32 i = 0; i < args->ops.count; i++) {

		obj = drm_gem_object_lookup(file, ops[i].handle);

		if (!obj) {

			ret = -ENOENT;

			goto err_ops;

		}



		ret = panthor_gem_sync(obj, ops[i].type, ops[i].offset,

				       ops[i].size);



		drm_gem_object_put(obj);



		if (ret)

			goto err_ops;

	}



err_ops:

	kvfree(ops);



	return ret;

}



static int

panthor_open(struct drm_device *ddev, struct drm_file *file)

{
@@ -1470,6 +1508,7 @@ static const struct drm_ioctl_desc panthor_drm_driver_ioctls[] = { 
	PANTHOR_IOCTL(GROUP_SUBMIT, group_submit, DRM_RENDER_ALLOW),

	PANTHOR_IOCTL(BO_SET_LABEL, bo_set_label, DRM_RENDER_ALLOW),

	PANTHOR_IOCTL(SET_USER_MMIO_OFFSET, set_user_mmio_offset, DRM_RENDER_ALLOW),

	PANTHOR_IOCTL(BO_SYNC, bo_sync, DRM_RENDER_ALLOW),

};



static int panthor_mmap(struct file *filp, struct vm_area_struct *vma)

drivers/gpu/drm/panthor/panthor_gem.c

+85 −0
Original line number Diff line number Diff line
@@ -465,6 +465,91 @@ panthor_gem_kernel_bo_set_label(struct panthor_kernel_bo *bo, const char *label) 
	panthor_gem_bo_set_label(bo->obj, str);

}



int

panthor_gem_sync(struct drm_gem_object *obj, u32 type,

		 u64 offset, u64 size)

{

	struct panthor_gem_object *bo = to_panthor_bo(obj);

	struct drm_gem_shmem_object *shmem = &bo->base;

	const struct drm_device *dev = shmem->base.dev;

	struct sg_table *sgt;

	struct scatterlist *sgl;

	unsigned int count;



	/* Make sure the range is in bounds. */

	if (offset + size < offset || offset + size > shmem->base.size)

		return -EINVAL;



	/* Disallow CPU-cache maintenance on imported buffers. */

	if (drm_gem_is_imported(&shmem->base))

		return -EINVAL;



	switch (type) {

	case DRM_PANTHOR_BO_SYNC_CPU_CACHE_FLUSH:

	case DRM_PANTHOR_BO_SYNC_CPU_CACHE_FLUSH_AND_INVALIDATE:

		break;



	default:

		return -EINVAL;

	}



	/* Don't bother if it's WC-mapped */

	if (shmem->map_wc)

		return 0;



	/* Nothing to do if the size is zero. */

	if (size == 0)

		return 0;



	sgt = drm_gem_shmem_get_pages_sgt(shmem);

	if (IS_ERR(sgt))

		return PTR_ERR(sgt);



	for_each_sgtable_dma_sg(sgt, sgl, count) {

		if (size == 0)

			break;



		dma_addr_t paddr = sg_dma_address(sgl);

		size_t len = sg_dma_len(sgl);



		if (len <= offset) {

			offset -= len;

			continue;

		}



		paddr += offset;

		len -= offset;

		len = min_t(size_t, len, size);

		size -= len;

		offset = 0;



		/* It's unclear whether dma_sync_xxx() is the right API to do CPU

		 * cache maintenance given an IOMMU can register their own

		 * implementation doing more than just CPU cache flushes/invalidation,

		 * and what we really care about here is CPU caches only, but that's

		 * the best we have that is both arch-agnostic and does at least the

		 * CPU cache maintenance on a <page,offset,size> tuple.

		 *

		 * Also, I wish we could do a single

		 *

		 *      dma_sync_single_for_device(BIDIR)

		 *

		 * and get a flush+invalidate, but that's not how it's implemented

		 * in practice (at least on arm64), so we have to make it

		 *

		 *      dma_sync_single_for_device(TO_DEVICE)

		 *      dma_sync_single_for_cpu(FROM_DEVICE)

		 *

		 * for the flush+invalidate case.

		 */

		dma_sync_single_for_device(dev->dev, paddr, len, DMA_TO_DEVICE);

		if (type == DRM_PANTHOR_BO_SYNC_CPU_CACHE_FLUSH_AND_INVALIDATE)

			dma_sync_single_for_cpu(dev->dev, paddr, len, DMA_FROM_DEVICE);

	}



	return 0;

}



#ifdef CONFIG_DEBUG_FS

struct gem_size_totals {

	size_t size;

drivers/gpu/drm/panthor/panthor_gem.h

+2 −0
Original line number Diff line number Diff line
@@ -148,6 +148,8 @@ panthor_gem_create_with_handle(struct drm_file *file, 


void panthor_gem_bo_set_label(struct drm_gem_object *obj, const char *label);

void panthor_gem_kernel_bo_set_label(struct panthor_kernel_bo *bo, const char *label);

int panthor_gem_sync(struct drm_gem_object *obj,

		     u32 type, u64 offset, u64 size);



struct drm_gem_object *

panthor_gem_prime_import(struct drm_device *dev,

include/uapi/drm/panthor_drm.h

+52 −0
Original line number Diff line number Diff line
@@ -144,6 +144,9 @@ enum drm_panthor_ioctl_id { 
	 * pgoff_t size.

	 */

	DRM_PANTHOR_SET_USER_MMIO_OFFSET,



	/** @DRM_PANTHOR_BO_SYNC: Sync BO data to/from the device */

	DRM_PANTHOR_BO_SYNC,

};



/**
@@ -1073,6 +1076,53 @@ struct drm_panthor_set_user_mmio_offset { 
	__u64 offset;

};



/**

 * enum drm_panthor_bo_sync_op_type - BO sync type

 */

enum drm_panthor_bo_sync_op_type {

	/** @DRM_PANTHOR_BO_SYNC_CPU_CACHE_FLUSH: Flush CPU caches. */

	DRM_PANTHOR_BO_SYNC_CPU_CACHE_FLUSH = 0,



	/** @DRM_PANTHOR_BO_SYNC_CPU_CACHE_FLUSH_AND_INVALIDATE: Flush and invalidate CPU caches. */

	DRM_PANTHOR_BO_SYNC_CPU_CACHE_FLUSH_AND_INVALIDATE = 1,

};



/**

 * struct drm_panthor_bo_sync_op - BO map sync op

 */

struct drm_panthor_bo_sync_op {

	/** @handle: Handle of the buffer object to sync. */

	__u32 handle;



	/** @type: Type of operation. */

	__u32 type;



	/**

	 * @offset: Offset into the BO at which the sync range starts.

	 *

	 * This will be rounded down to the nearest cache line as needed.

	 */

	__u64 offset;



	/**

	 * @size: Size of the range to sync

	 *

	 * @size + @offset will be rounded up to the nearest cache line as

	 * needed.

	 */

	__u64 size;

};



/**

 * struct drm_panthor_bo_sync - BO map sync request

 */

struct drm_panthor_bo_sync {

	/**

	 * @ops: Array of struct drm_panthor_bo_sync_op sync operations.

	 */

	struct drm_panthor_obj_array ops;

};



/**

 * DRM_IOCTL_PANTHOR() - Build a Panthor IOCTL number

 * @__access: Access type. Must be R, W or RW.
@@ -1119,6 +1169,8 @@ enum { 
		DRM_IOCTL_PANTHOR(WR, BO_SET_LABEL, bo_set_label),

	DRM_IOCTL_PANTHOR_SET_USER_MMIO_OFFSET =

		DRM_IOCTL_PANTHOR(WR, SET_USER_MMIO_OFFSET, set_user_mmio_offset),

	DRM_IOCTL_PANTHOR_BO_SYNC =

		DRM_IOCTL_PANTHOR(WR, BO_SYNC, bo_sync),

};



#if defined(__cplusplus)