[PATCH 1/8] drm/amdgpu: new resource cursor

[Christian König]

Any more comments on this set here or otherwise I'm going to push it 
with just Oaks ack.

Thanks,
Christian.

Am 08.03.21 um 14:40 schrieb Christian König:
> Allows to walk over the drm_mm nodes in a TTM resource object.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> Acked-by: Oak Zeng <Oak.Zeng at amd.com>
> Tested-by: Nirmoy Das <nirmoy.das at amd.com>
> ---
>   .../gpu/drm/amd/amdgpu/amdgpu_res_cursor.h    | 105 ++++++++++++++++++
>   1 file changed, 105 insertions(+)
>   create mode 100644 drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h
> new file mode 100644
> index 000000000000..1335e098510f
> --- /dev/null
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h
> @@ -0,0 +1,105 @@
> +// SPDX-License-Identifier: GPL-2.0 OR MIT
> +/*
> + * Copyright 2020 Advanced Micro Devices, Inc.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
> + * OTHER DEALINGS IN THE SOFTWARE.
> + *
> + * Authors: Christian König
> + */
> +
> +#ifndef __AMDGPU_RES_CURSOR_H__
> +#define __AMDGPU_RES_CURSOR_H__
> +
> +#include <drm/drm_mm.h>
> +#include <drm/ttm/ttm_resource.h>
> +
> +/* state back for walking over vram_mgr and gtt_mgr allocations */
> +struct amdgpu_res_cursor {
> +	uint64_t		start;
> +	uint64_t		size;
> +	uint64_t		remaining;
> +	struct drm_mm_node	*node;
> +};
> +
> +/**
> + * amdgpu_res_first - initialize a amdgpu_res_cursor
> + *
> + * @res: TTM resource object to walk
> + * @start: Start of the range
> + * @size: Size of the range
> + * @cur: cursor object to initialize
> + *
> + * Start walking over the range of allocations between @start and @size.
> + */
> +static inline void amdgpu_res_first(struct ttm_resource *res,
> +				    uint64_t start, uint64_t size,
> +				    struct amdgpu_res_cursor *cur)
> +{
> +	struct drm_mm_node *node;
> +
> +	if (!res || !res->mm_node) {
> +		cur->start = start;
> +		cur->size = size;
> +		cur->remaining = size;
> +		cur->node = NULL;
> +		return;
> +	}
> +
> +	BUG_ON(start + size > res->num_pages << PAGE_SHIFT);
> +
> +	node = res->mm_node;
> +	while (start > node->size << PAGE_SHIFT)
> +		start -= node++->size << PAGE_SHIFT;
> +
> +	cur->start = (node->start << PAGE_SHIFT) + start;
> +	cur->size = (node->size << PAGE_SHIFT) - start;
> +	cur->remaining = size;
> +	cur->node = node;
> +}
> +
> +/**
> + * amdgpu_res_next - advance the cursor
> + *
> + * @cur: the cursor to advance
> + * @size: number of bytes to move forward
> + *
> + * Move the cursor @size bytes forwrad, walking to the next node if necessary.
> + */
> +static inline void amdgpu_res_next(struct amdgpu_res_cursor *cur, uint64_t size)
> +{
> +	struct drm_mm_node *node = cur->node;
> +
> +	BUG_ON(size > cur->remaining);
> +
> +	cur->remaining -= size;
> +	if (!cur->remaining)
> +		return;
> +
> +	cur->size -= size;
> +	if (cur->size) {
> +		cur->start += size;
> +		return;
> +	}
> +
> +	cur->node = ++node;
> +	cur->start = node->start << PAGE_SHIFT;
> +	cur->size = min(node->size << PAGE_SHIFT, cur->remaining);
> +}
> +
> +#endif