137d63f8fSChris Wilson /*
237d63f8fSChris Wilson * SPDX-License-Identifier: MIT
337d63f8fSChris Wilson *
437d63f8fSChris Wilson * Copyright © 2016 Intel Corporation
537d63f8fSChris Wilson */
637d63f8fSChris Wilson
737d63f8fSChris Wilson #ifndef I915_SCATTERLIST_H
837d63f8fSChris Wilson #define I915_SCATTERLIST_H
937d63f8fSChris Wilson
1037d63f8fSChris Wilson #include <linux/pfn.h>
1137d63f8fSChris Wilson #include <linux/scatterlist.h>
1278a07fe7SRobert Beckett #include <linux/dma-mapping.h>
1378a07fe7SRobert Beckett #include <xen/xen.h>
1437d63f8fSChris Wilson
1537d63f8fSChris Wilson #include "i915_gem.h"
1637d63f8fSChris Wilson
17d1487389SThomas Hellström struct drm_mm_node;
18f701b16dSMatthew Auld struct ttm_resource;
19d1487389SThomas Hellström
2037d63f8fSChris Wilson /*
2137d63f8fSChris Wilson * Optimised SGL iterator for GEM objects
2237d63f8fSChris Wilson */
2337d63f8fSChris Wilson static __always_inline struct sgt_iter {
2437d63f8fSChris Wilson struct scatterlist *sgp;
2537d63f8fSChris Wilson union {
2637d63f8fSChris Wilson unsigned long pfn;
2737d63f8fSChris Wilson dma_addr_t dma;
2837d63f8fSChris Wilson };
2937d63f8fSChris Wilson unsigned int curr;
3037d63f8fSChris Wilson unsigned int max;
__sgt_iter(struct scatterlist * sgl,bool dma)3137d63f8fSChris Wilson } __sgt_iter(struct scatterlist *sgl, bool dma) {
3237d63f8fSChris Wilson struct sgt_iter s = { .sgp = sgl };
3337d63f8fSChris Wilson
348a473dbaSTvrtko Ursulin if (dma && s.sgp && sg_dma_len(s.sgp) == 0) {
358a473dbaSTvrtko Ursulin s.sgp = NULL;
368a473dbaSTvrtko Ursulin } else if (s.sgp) {
3737d63f8fSChris Wilson s.max = s.curr = s.sgp->offset;
388a473dbaSTvrtko Ursulin if (dma) {
3937d63f8fSChris Wilson s.dma = sg_dma_address(s.sgp);
408a473dbaSTvrtko Ursulin s.max += sg_dma_len(s.sgp);
418a473dbaSTvrtko Ursulin } else {
4237d63f8fSChris Wilson s.pfn = page_to_pfn(sg_page(s.sgp));
438a473dbaSTvrtko Ursulin s.max += s.sgp->length;
448a473dbaSTvrtko Ursulin }
4537d63f8fSChris Wilson }
4637d63f8fSChris Wilson
4737d63f8fSChris Wilson return s;
4837d63f8fSChris Wilson }
4937d63f8fSChris Wilson
__sg_page_count(const struct scatterlist * sg)5037d63f8fSChris Wilson static inline int __sg_page_count(const struct scatterlist *sg)
5137d63f8fSChris Wilson {
5237d63f8fSChris Wilson return sg->length >> PAGE_SHIFT;
5337d63f8fSChris Wilson }
5437d63f8fSChris Wilson
__sg_dma_page_count(const struct scatterlist * sg)55934941edSTvrtko Ursulin static inline int __sg_dma_page_count(const struct scatterlist *sg)
56934941edSTvrtko Ursulin {
57934941edSTvrtko Ursulin return sg_dma_len(sg) >> PAGE_SHIFT;
58934941edSTvrtko Ursulin }
59934941edSTvrtko Ursulin
____sg_next(struct scatterlist * sg)6037d63f8fSChris Wilson static inline struct scatterlist *____sg_next(struct scatterlist *sg)
6137d63f8fSChris Wilson {
6237d63f8fSChris Wilson ++sg;
6337d63f8fSChris Wilson if (unlikely(sg_is_chain(sg)))
6437d63f8fSChris Wilson sg = sg_chain_ptr(sg);
6537d63f8fSChris Wilson return sg;
6637d63f8fSChris Wilson }
6737d63f8fSChris Wilson
6837d63f8fSChris Wilson /**
6937d63f8fSChris Wilson * __sg_next - return the next scatterlist entry in a list
7037d63f8fSChris Wilson * @sg: The current sg entry
7137d63f8fSChris Wilson *
7237d63f8fSChris Wilson * Description:
7337d63f8fSChris Wilson * If the entry is the last, return NULL; otherwise, step to the next
7437d63f8fSChris Wilson * element in the array (@sg@+1). If that's a chain pointer, follow it;
7537d63f8fSChris Wilson * otherwise just return the pointer to the current element.
7637d63f8fSChris Wilson **/
__sg_next(struct scatterlist * sg)7737d63f8fSChris Wilson static inline struct scatterlist *__sg_next(struct scatterlist *sg)
7837d63f8fSChris Wilson {
7937d63f8fSChris Wilson return sg_is_last(sg) ? NULL : ____sg_next(sg);
8037d63f8fSChris Wilson }
8137d63f8fSChris Wilson
8237d63f8fSChris Wilson /**
8331444afbSMatthew Auld * __for_each_sgt_daddr - iterate over the device addresses of the given sg_table
8431444afbSMatthew Auld * @__dp: Device address (output)
8537d63f8fSChris Wilson * @__iter: 'struct sgt_iter' (iterator state, internal)
8637d63f8fSChris Wilson * @__sgt: sg_table to iterate over (input)
8737d63f8fSChris Wilson * @__step: step size
8837d63f8fSChris Wilson */
8931444afbSMatthew Auld #define __for_each_sgt_daddr(__dp, __iter, __sgt, __step) \
9037d63f8fSChris Wilson for ((__iter) = __sgt_iter((__sgt)->sgl, true); \
9131444afbSMatthew Auld ((__dp) = (__iter).dma + (__iter).curr), (__iter).sgp; \
9237d63f8fSChris Wilson (((__iter).curr += (__step)) >= (__iter).max) ? \
9337d63f8fSChris Wilson (__iter) = __sgt_iter(__sg_next((__iter).sgp), true), 0 : 0)
9437d63f8fSChris Wilson
9537d63f8fSChris Wilson /**
9637d63f8fSChris Wilson * for_each_sgt_page - iterate over the pages of the given sg_table
9737d63f8fSChris Wilson * @__pp: page pointer (output)
9837d63f8fSChris Wilson * @__iter: 'struct sgt_iter' (iterator state, internal)
9937d63f8fSChris Wilson * @__sgt: sg_table to iterate over (input)
10037d63f8fSChris Wilson */
10137d63f8fSChris Wilson #define for_each_sgt_page(__pp, __iter, __sgt) \
10237d63f8fSChris Wilson for ((__iter) = __sgt_iter((__sgt)->sgl, false); \
10337d63f8fSChris Wilson ((__pp) = (__iter).pfn == 0 ? NULL : \
10437d63f8fSChris Wilson pfn_to_page((__iter).pfn + ((__iter).curr >> PAGE_SHIFT))); \
10537d63f8fSChris Wilson (((__iter).curr += PAGE_SIZE) >= (__iter).max) ? \
10637d63f8fSChris Wilson (__iter) = __sgt_iter(__sg_next((__iter).sgp), false), 0 : 0)
10737d63f8fSChris Wilson
10862445a97SThomas Hellström /**
10962445a97SThomas Hellström * i915_sg_dma_sizes - Record the dma segment sizes of a scatterlist
11062445a97SThomas Hellström * @sg: The scatterlist
11162445a97SThomas Hellström *
11262445a97SThomas Hellström * Return: An unsigned int with segment sizes logically or'ed together.
11362445a97SThomas Hellström * A caller can use this information to determine what hardware page table
11462445a97SThomas Hellström * entry sizes can be used to map the memory represented by the scatterlist.
11562445a97SThomas Hellström */
i915_sg_dma_sizes(struct scatterlist * sg)11662445a97SThomas Hellström static inline unsigned int i915_sg_dma_sizes(struct scatterlist *sg)
11737d63f8fSChris Wilson {
11837d63f8fSChris Wilson unsigned int page_sizes;
11937d63f8fSChris Wilson
12037d63f8fSChris Wilson page_sizes = 0;
12162445a97SThomas Hellström while (sg && sg_dma_len(sg)) {
12237d63f8fSChris Wilson GEM_BUG_ON(sg->offset);
12362445a97SThomas Hellström GEM_BUG_ON(!IS_ALIGNED(sg_dma_len(sg), PAGE_SIZE));
12462445a97SThomas Hellström page_sizes |= sg_dma_len(sg);
12537d63f8fSChris Wilson sg = __sg_next(sg);
12637d63f8fSChris Wilson }
12737d63f8fSChris Wilson
12837d63f8fSChris Wilson return page_sizes;
12937d63f8fSChris Wilson }
13037d63f8fSChris Wilson
i915_sg_segment_size(struct device * dev)13178a07fe7SRobert Beckett static inline unsigned int i915_sg_segment_size(struct device *dev)
13237d63f8fSChris Wilson {
13378a07fe7SRobert Beckett size_t max = min_t(size_t, UINT_MAX, dma_max_mapping_size(dev));
13437d63f8fSChris Wilson
13578a07fe7SRobert Beckett /*
13678a07fe7SRobert Beckett * For Xen PV guests pages aren't contiguous in DMA (machine) address
13778a07fe7SRobert Beckett * space. The DMA API takes care of that both in dma_alloc_* (by
13878a07fe7SRobert Beckett * calling into the hypervisor to make the pages contiguous) and in
13978a07fe7SRobert Beckett * dma_map_* (by bounce buffering). But i915 abuses ignores the
14078a07fe7SRobert Beckett * coherency aspects of the DMA API and thus can't cope with bounce
14178a07fe7SRobert Beckett * buffering actually happening, so add a hack here to force small
14278a07fe7SRobert Beckett * allocations and mappings when running in PV mode on Xen.
14378a07fe7SRobert Beckett *
14478a07fe7SRobert Beckett * Note this will still break if bounce buffering is required for other
14578a07fe7SRobert Beckett * reasons, like confidential computing hypervisors or PCIe root ports
14678a07fe7SRobert Beckett * with addressing limitations.
14778a07fe7SRobert Beckett */
14878a07fe7SRobert Beckett if (xen_pv_domain())
14978a07fe7SRobert Beckett max = PAGE_SIZE;
15078a07fe7SRobert Beckett return round_down(max, PAGE_SIZE);
15137d63f8fSChris Wilson }
15237d63f8fSChris Wilson
15337d63f8fSChris Wilson bool i915_sg_trim(struct sg_table *orig_st);
15437d63f8fSChris Wilson
155cad7109aSThomas Hellström /**
156cad7109aSThomas Hellström * struct i915_refct_sgt_ops - Operations structure for struct i915_refct_sgt
157cad7109aSThomas Hellström */
158cad7109aSThomas Hellström struct i915_refct_sgt_ops {
159cad7109aSThomas Hellström /**
160*9d7fe94dSJani Nikula * @release: Free the memory of the struct i915_refct_sgt
161cad7109aSThomas Hellström */
162cad7109aSThomas Hellström void (*release)(struct kref *ref);
163cad7109aSThomas Hellström };
164cad7109aSThomas Hellström
165cad7109aSThomas Hellström /**
166cad7109aSThomas Hellström * struct i915_refct_sgt - A refcounted scatter-gather table
167cad7109aSThomas Hellström * @kref: struct kref for refcounting
168cad7109aSThomas Hellström * @table: struct sg_table holding the scatter-gather table itself. Note that
169cad7109aSThomas Hellström * @table->sgl = NULL can be used to determine whether a scatter-gather table
170cad7109aSThomas Hellström * is present or not.
171cad7109aSThomas Hellström * @size: The size in bytes of the underlying memory buffer
172cad7109aSThomas Hellström * @ops: The operations structure.
173cad7109aSThomas Hellström */
174cad7109aSThomas Hellström struct i915_refct_sgt {
175cad7109aSThomas Hellström struct kref kref;
176cad7109aSThomas Hellström struct sg_table table;
177cad7109aSThomas Hellström size_t size;
178cad7109aSThomas Hellström const struct i915_refct_sgt_ops *ops;
179cad7109aSThomas Hellström };
180cad7109aSThomas Hellström
181cad7109aSThomas Hellström /**
182cad7109aSThomas Hellström * i915_refct_sgt_put - Put a refcounted sg-table
1838b2a7394SJani Nikula * @rsgt: the struct i915_refct_sgt to put.
184cad7109aSThomas Hellström */
i915_refct_sgt_put(struct i915_refct_sgt * rsgt)185cad7109aSThomas Hellström static inline void i915_refct_sgt_put(struct i915_refct_sgt *rsgt)
186cad7109aSThomas Hellström {
187cad7109aSThomas Hellström if (rsgt)
188cad7109aSThomas Hellström kref_put(&rsgt->kref, rsgt->ops->release);
189cad7109aSThomas Hellström }
190cad7109aSThomas Hellström
191cad7109aSThomas Hellström /**
192cad7109aSThomas Hellström * i915_refct_sgt_get - Get a refcounted sg-table
1938b2a7394SJani Nikula * @rsgt: the struct i915_refct_sgt to get.
194cad7109aSThomas Hellström */
195cad7109aSThomas Hellström static inline struct i915_refct_sgt *
i915_refct_sgt_get(struct i915_refct_sgt * rsgt)196cad7109aSThomas Hellström i915_refct_sgt_get(struct i915_refct_sgt *rsgt)
197cad7109aSThomas Hellström {
198cad7109aSThomas Hellström kref_get(&rsgt->kref);
199cad7109aSThomas Hellström return rsgt;
200cad7109aSThomas Hellström }
201cad7109aSThomas Hellström
202cad7109aSThomas Hellström /**
203cad7109aSThomas Hellström * __i915_refct_sgt_init - Initialize a refcounted sg-list with a custom
204cad7109aSThomas Hellström * operations structure
2058b2a7394SJani Nikula * @rsgt: The struct i915_refct_sgt to initialize.
206cad7109aSThomas Hellström * @size: Size in bytes of the underlying memory buffer.
207cad7109aSThomas Hellström * @ops: A customized operations structure in case the refcounted sg-list
208cad7109aSThomas Hellström * is embedded into another structure.
209cad7109aSThomas Hellström */
__i915_refct_sgt_init(struct i915_refct_sgt * rsgt,size_t size,const struct i915_refct_sgt_ops * ops)210cad7109aSThomas Hellström static inline void __i915_refct_sgt_init(struct i915_refct_sgt *rsgt,
211cad7109aSThomas Hellström size_t size,
212cad7109aSThomas Hellström const struct i915_refct_sgt_ops *ops)
213cad7109aSThomas Hellström {
214cad7109aSThomas Hellström kref_init(&rsgt->kref);
215cad7109aSThomas Hellström rsgt->table.sgl = NULL;
216cad7109aSThomas Hellström rsgt->size = size;
217cad7109aSThomas Hellström rsgt->ops = ops;
218cad7109aSThomas Hellström }
219cad7109aSThomas Hellström
220cad7109aSThomas Hellström void i915_refct_sgt_init(struct i915_refct_sgt *rsgt, size_t size);
221cad7109aSThomas Hellström
222cad7109aSThomas Hellström struct i915_refct_sgt *i915_rsgt_from_mm_node(const struct drm_mm_node *node,
223bc99f120SMatthew Auld u64 region_start,
2249306b2b2SMatthew Auld u32 page_alignment);
225f701b16dSMatthew Auld
226cad7109aSThomas Hellström struct i915_refct_sgt *i915_rsgt_from_buddy_resource(struct ttm_resource *res,
227bc99f120SMatthew Auld u64 region_start,
2289306b2b2SMatthew Auld u32 page_alignment);
229f701b16dSMatthew Auld
23037d63f8fSChris Wilson #endif
231