232 lines
6.4 KiB
C
232 lines
6.4 KiB
C
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/*
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* SPDX-License-Identifier: MIT
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*
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* Copyright © 2016 Intel Corporation
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*/
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#ifndef I915_SCATTERLIST_H
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#define I915_SCATTERLIST_H
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#include <linux/pfn.h>
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#include <linux/scatterlist.h>
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#include <linux/dma-mapping.h>
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#include <xen/xen.h>
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#include "i915_gem.h"
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struct drm_mm_node;
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struct ttm_resource;
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/*
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* Optimised SGL iterator for GEM objects
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*/
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static __always_inline struct sgt_iter {
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struct scatterlist *sgp;
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union {
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unsigned long pfn;
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dma_addr_t dma;
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};
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unsigned int curr;
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unsigned int max;
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} __sgt_iter(struct scatterlist *sgl, bool dma) {
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struct sgt_iter s = { .sgp = sgl };
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if (dma && s.sgp && sg_dma_len(s.sgp) == 0) {
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s.sgp = NULL;
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} else if (s.sgp) {
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s.max = s.curr = s.sgp->offset;
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if (dma) {
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s.dma = sg_dma_address(s.sgp);
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s.max += sg_dma_len(s.sgp);
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} else {
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s.pfn = page_to_pfn(sg_page(s.sgp));
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s.max += s.sgp->length;
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}
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}
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return s;
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}
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static inline int __sg_page_count(const struct scatterlist *sg)
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{
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return sg->length >> PAGE_SHIFT;
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}
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static inline int __sg_dma_page_count(const struct scatterlist *sg)
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{
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return sg_dma_len(sg) >> PAGE_SHIFT;
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}
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static inline struct scatterlist *____sg_next(struct scatterlist *sg)
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{
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++sg;
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if (unlikely(sg_is_chain(sg)))
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sg = sg_chain_ptr(sg);
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return sg;
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}
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/**
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* __sg_next - return the next scatterlist entry in a list
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* @sg: The current sg entry
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*
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* Description:
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* If the entry is the last, return NULL; otherwise, step to the next
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* element in the array (@sg@+1). If that's a chain pointer, follow it;
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* otherwise just return the pointer to the current element.
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**/
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static inline struct scatterlist *__sg_next(struct scatterlist *sg)
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{
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return sg_is_last(sg) ? NULL : ____sg_next(sg);
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}
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/**
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* __for_each_sgt_daddr - iterate over the device addresses of the given sg_table
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* @__dp: Device address (output)
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* @__iter: 'struct sgt_iter' (iterator state, internal)
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* @__sgt: sg_table to iterate over (input)
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* @__step: step size
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*/
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#define __for_each_sgt_daddr(__dp, __iter, __sgt, __step) \
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for ((__iter) = __sgt_iter((__sgt)->sgl, true); \
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((__dp) = (__iter).dma + (__iter).curr), (__iter).sgp; \
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(((__iter).curr += (__step)) >= (__iter).max) ? \
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(__iter) = __sgt_iter(__sg_next((__iter).sgp), true), 0 : 0)
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/**
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* for_each_sgt_page - iterate over the pages of the given sg_table
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* @__pp: page pointer (output)
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* @__iter: 'struct sgt_iter' (iterator state, internal)
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* @__sgt: sg_table to iterate over (input)
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*/
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#define for_each_sgt_page(__pp, __iter, __sgt) \
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for ((__iter) = __sgt_iter((__sgt)->sgl, false); \
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((__pp) = (__iter).pfn == 0 ? NULL : \
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pfn_to_page((__iter).pfn + ((__iter).curr >> PAGE_SHIFT))); \
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(((__iter).curr += PAGE_SIZE) >= (__iter).max) ? \
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(__iter) = __sgt_iter(__sg_next((__iter).sgp), false), 0 : 0)
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/**
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* i915_sg_dma_sizes - Record the dma segment sizes of a scatterlist
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* @sg: The scatterlist
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*
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* Return: An unsigned int with segment sizes logically or'ed together.
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* A caller can use this information to determine what hardware page table
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* entry sizes can be used to map the memory represented by the scatterlist.
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*/
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static inline unsigned int i915_sg_dma_sizes(struct scatterlist *sg)
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{
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unsigned int page_sizes;
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page_sizes = 0;
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while (sg && sg_dma_len(sg)) {
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GEM_BUG_ON(sg->offset);
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GEM_BUG_ON(!IS_ALIGNED(sg_dma_len(sg), PAGE_SIZE));
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page_sizes |= sg_dma_len(sg);
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sg = __sg_next(sg);
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}
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return page_sizes;
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}
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static inline unsigned int i915_sg_segment_size(struct device *dev)
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{
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size_t max = min_t(size_t, UINT_MAX, dma_max_mapping_size(dev));
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/*
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* For Xen PV guests pages aren't contiguous in DMA (machine) address
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* space. The DMA API takes care of that both in dma_alloc_* (by
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* calling into the hypervisor to make the pages contiguous) and in
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* dma_map_* (by bounce buffering). But i915 abuses ignores the
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* coherency aspects of the DMA API and thus can't cope with bounce
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* buffering actually happening, so add a hack here to force small
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* allocations and mappings when running in PV mode on Xen.
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*
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* Note this will still break if bounce buffering is required for other
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* reasons, like confidential computing hypervisors or PCIe root ports
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* with addressing limitations.
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*/
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if (xen_pv_domain())
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max = PAGE_SIZE;
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return round_down(max, PAGE_SIZE);
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}
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bool i915_sg_trim(struct sg_table *orig_st);
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/**
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* struct i915_refct_sgt_ops - Operations structure for struct i915_refct_sgt
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*/
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struct i915_refct_sgt_ops {
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/**
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* release() - Free the memory of the struct i915_refct_sgt
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* @ref: struct kref that is embedded in the struct i915_refct_sgt
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*/
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void (*release)(struct kref *ref);
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};
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/**
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* struct i915_refct_sgt - A refcounted scatter-gather table
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* @kref: struct kref for refcounting
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* @table: struct sg_table holding the scatter-gather table itself. Note that
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* @table->sgl = NULL can be used to determine whether a scatter-gather table
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* is present or not.
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* @size: The size in bytes of the underlying memory buffer
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* @ops: The operations structure.
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*/
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struct i915_refct_sgt {
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struct kref kref;
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struct sg_table table;
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size_t size;
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const struct i915_refct_sgt_ops *ops;
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};
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/**
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* i915_refct_sgt_put - Put a refcounted sg-table
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* @rsgt the struct i915_refct_sgt to put.
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*/
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static inline void i915_refct_sgt_put(struct i915_refct_sgt *rsgt)
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{
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if (rsgt)
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kref_put(&rsgt->kref, rsgt->ops->release);
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}
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/**
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* i915_refct_sgt_get - Get a refcounted sg-table
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* @rsgt the struct i915_refct_sgt to get.
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*/
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static inline struct i915_refct_sgt *
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i915_refct_sgt_get(struct i915_refct_sgt *rsgt)
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{
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kref_get(&rsgt->kref);
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return rsgt;
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}
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/**
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* __i915_refct_sgt_init - Initialize a refcounted sg-list with a custom
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* operations structure
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* @rsgt The struct i915_refct_sgt to initialize.
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* @size: Size in bytes of the underlying memory buffer.
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* @ops: A customized operations structure in case the refcounted sg-list
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* is embedded into another structure.
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*/
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static inline void __i915_refct_sgt_init(struct i915_refct_sgt *rsgt,
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size_t size,
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const struct i915_refct_sgt_ops *ops)
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{
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kref_init(&rsgt->kref);
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rsgt->table.sgl = NULL;
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rsgt->size = size;
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rsgt->ops = ops;
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}
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void i915_refct_sgt_init(struct i915_refct_sgt *rsgt, size_t size);
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struct i915_refct_sgt *i915_rsgt_from_mm_node(const struct drm_mm_node *node,
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u64 region_start,
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u32 page_alignment);
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struct i915_refct_sgt *i915_rsgt_from_buddy_resource(struct ttm_resource *res,
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u64 region_start,
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u32 page_alignment);
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#endif
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