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Dan Williams9476df72016-01-15 16:56:19 -08001#ifndef _LINUX_MEMREMAP_H_
2#define _LINUX_MEMREMAP_H_
3#include <linux/mm.h>
Dan Williams5c2c2582016-01-15 16:56:49 -08004#include <linux/ioport.h>
5#include <linux/percpu-refcount.h>
Dan Williams9476df72016-01-15 16:56:19 -08006
7struct resource;
8struct device;
Dan Williams4b94ffd2016-01-15 16:56:22 -08009
10/**
11 * struct vmem_altmap - pre-allocated storage for vmemmap_populate
12 * @base_pfn: base of the entire dev_pagemap mapping
13 * @reserve: pages mapped, but reserved for driver use (relative to @base)
14 * @free: free pages set aside in the mapping for memmap storage
15 * @align: pages reserved to meet allocation alignments
16 * @alloc: track pages consumed, private to vmemmap_populate()
17 */
18struct vmem_altmap {
19 const unsigned long base_pfn;
20 const unsigned long reserve;
21 unsigned long free;
22 unsigned long align;
23 unsigned long alloc;
24};
25
26unsigned long vmem_altmap_offset(struct vmem_altmap *altmap);
27void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns);
28
29#if defined(CONFIG_SPARSEMEM_VMEMMAP) && defined(CONFIG_ZONE_DEVICE)
30struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start);
31#else
32static inline struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
33{
34 return NULL;
35}
36#endif
37
Dan Williams9476df72016-01-15 16:56:19 -080038/**
39 * struct dev_pagemap - metadata for ZONE_DEVICE mappings
Dan Williams4b94ffd2016-01-15 16:56:22 -080040 * @altmap: pre-allocated/reserved memory for vmemmap allocations
Dan Williams5c2c2582016-01-15 16:56:49 -080041 * @res: physical address range covered by @ref
42 * @ref: reference count that pins the devm_memremap_pages() mapping
Dan Williams9476df72016-01-15 16:56:19 -080043 * @dev: host device of the mapping for debug
44 */
45struct dev_pagemap {
Dan Williams4b94ffd2016-01-15 16:56:22 -080046 struct vmem_altmap *altmap;
47 const struct resource *res;
Dan Williams5c2c2582016-01-15 16:56:49 -080048 struct percpu_ref *ref;
Dan Williams9476df72016-01-15 16:56:19 -080049 struct device *dev;
50};
51
52#ifdef CONFIG_ZONE_DEVICE
Dan Williams4b94ffd2016-01-15 16:56:22 -080053void *devm_memremap_pages(struct device *dev, struct resource *res,
Dan Williams5c2c2582016-01-15 16:56:49 -080054 struct percpu_ref *ref, struct vmem_altmap *altmap);
Dan Williams9476df72016-01-15 16:56:19 -080055struct dev_pagemap *find_dev_pagemap(resource_size_t phys);
56#else
57static inline void *devm_memremap_pages(struct device *dev,
Dan Williams5c2c2582016-01-15 16:56:49 -080058 struct resource *res, struct percpu_ref *ref,
59 struct vmem_altmap *altmap)
Dan Williams9476df72016-01-15 16:56:19 -080060{
61 /*
62 * Fail attempts to call devm_memremap_pages() without
63 * ZONE_DEVICE support enabled, this requires callers to fall
64 * back to plain devm_memremap() based on config
65 */
66 WARN_ON_ONCE(1);
67 return ERR_PTR(-ENXIO);
68}
69
70static inline struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
71{
72 return NULL;
73}
74#endif
Dan Williams5c2c2582016-01-15 16:56:49 -080075
76/**
77 * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
78 * @pfn: page frame number to lookup page_map
79 * @pgmap: optional known pgmap that already has a reference
80 *
81 * @pgmap allows the overhead of a lookup to be bypassed when @pfn lands in the
82 * same mapping.
83 */
84static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
85 struct dev_pagemap *pgmap)
86{
87 const struct resource *res = pgmap ? pgmap->res : NULL;
88 resource_size_t phys = PFN_PHYS(pfn);
89
90 /*
91 * In the cached case we're already holding a live reference so
92 * we can simply do a blind increment
93 */
94 if (res && phys >= res->start && phys <= res->end) {
95 percpu_ref_get(pgmap->ref);
96 return pgmap;
97 }
98
99 /* fall back to slow path lookup */
100 rcu_read_lock();
101 pgmap = find_dev_pagemap(phys);
102 if (pgmap && !percpu_ref_tryget_live(pgmap->ref))
103 pgmap = NULL;
104 rcu_read_unlock();
105
106 return pgmap;
107}
108
109static inline void put_dev_pagemap(struct dev_pagemap *pgmap)
110{
111 if (pgmap)
112 percpu_ref_put(pgmap->ref);
113}
Dan Williams9476df72016-01-15 16:56:19 -0800114#endif /* _LINUX_MEMREMAP_H_ */