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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
9476df7d DW |
2 | #ifndef _LINUX_MEMREMAP_H_ |
3 | #define _LINUX_MEMREMAP_H_ | |
5c2c2587 DW |
4 | #include <linux/ioport.h> |
5 | #include <linux/percpu-refcount.h> | |
9476df7d DW |
6 | |
7 | struct resource; | |
8 | struct device; | |
4b94ffdc DW |
9 | |
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 | */ | |
18 | struct 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 | ||
5042db43 JG |
26 | /* |
27 | * Specialize ZONE_DEVICE memory into multiple types each having differents | |
28 | * usage. | |
29 | * | |
5042db43 JG |
30 | * MEMORY_DEVICE_PRIVATE: |
31 | * Device memory that is not directly addressable by the CPU: CPU can neither | |
32 | * read nor write private memory. In this case, we do still have struct pages | |
33 | * backing the device memory. Doing so simplifies the implementation, but it is | |
34 | * important to remember that there are certain points at which the struct page | |
35 | * must be treated as an opaque object, rather than a "normal" struct page. | |
36 | * | |
37 | * A more complete discussion of unaddressable memory may be found in | |
ad56b738 | 38 | * include/linux/hmm.h and Documentation/vm/hmm.rst. |
df6ad698 | 39 | * |
e7638488 DW |
40 | * MEMORY_DEVICE_FS_DAX: |
41 | * Host memory that has similar access semantics as System RAM i.e. DMA | |
42 | * coherent and supports page pinning. In support of coordinating page | |
43 | * pinning vs other operations MEMORY_DEVICE_FS_DAX arranges for a | |
44 | * wakeup event whenever a page is unpinned and becomes idle. This | |
45 | * wakeup is used to coordinate physical address space management (ex: | |
46 | * fs truncate/hole punch) vs pinned pages (ex: device dma). | |
52916982 | 47 | * |
3ed2dcdf CH |
48 | * MEMORY_DEVICE_DEVDAX: |
49 | * Host memory that has similar access semantics as System RAM i.e. DMA | |
50 | * coherent and supports page pinning. In contrast to | |
51 | * MEMORY_DEVICE_FS_DAX, this memory is access via a device-dax | |
52 | * character device. | |
53 | * | |
52916982 LG |
54 | * MEMORY_DEVICE_PCI_P2PDMA: |
55 | * Device memory residing in a PCI BAR intended for use with Peer-to-Peer | |
56 | * transactions. | |
5042db43 JG |
57 | */ |
58 | enum memory_type { | |
3ed2dcdf | 59 | /* 0 is reserved to catch uninitialized type fields */ |
e7638488 | 60 | MEMORY_DEVICE_PRIVATE = 1, |
e7638488 | 61 | MEMORY_DEVICE_FS_DAX, |
3ed2dcdf | 62 | MEMORY_DEVICE_DEVDAX, |
52916982 | 63 | MEMORY_DEVICE_PCI_P2PDMA, |
5042db43 JG |
64 | }; |
65 | ||
1e240e8d CH |
66 | struct dev_pagemap_ops { |
67 | /* | |
68 | * Called once the page refcount reaches 1. (ZONE_DEVICE pages never | |
69 | * reach 0 refcount unless there is a refcount bug. This allows the | |
70 | * device driver to implement its own memory management.) | |
71 | */ | |
80a72d0a | 72 | void (*page_free)(struct page *page); |
1e240e8d CH |
73 | |
74 | /* | |
75 | * Transition the refcount in struct dev_pagemap to the dead state. | |
76 | */ | |
d8668bb0 | 77 | void (*kill)(struct dev_pagemap *pgmap); |
1e240e8d CH |
78 | |
79 | /* | |
80 | * Wait for refcount in struct dev_pagemap to be idle and reap it. | |
81 | */ | |
d8668bb0 | 82 | void (*cleanup)(struct dev_pagemap *pgmap); |
897e6365 CH |
83 | |
84 | /* | |
85 | * Used for private (un-addressable) device memory only. Must migrate | |
86 | * the page back to a CPU accessible page. | |
87 | */ | |
88 | vm_fault_t (*migrate_to_ram)(struct vm_fault *vmf); | |
1e240e8d | 89 | }; |
5042db43 | 90 | |
514caf23 CH |
91 | #define PGMAP_ALTMAP_VALID (1 << 0) |
92 | ||
9476df7d DW |
93 | /** |
94 | * struct dev_pagemap - metadata for ZONE_DEVICE mappings | |
4b94ffdc | 95 | * @altmap: pre-allocated/reserved memory for vmemmap allocations |
5c2c2587 DW |
96 | * @res: physical address range covered by @ref |
97 | * @ref: reference count that pins the devm_memremap_pages() mapping | |
24917f6b CH |
98 | * @internal_ref: internal reference if @ref is not provided by the caller |
99 | * @done: completion for @internal_ref | |
9476df7d | 100 | * @dev: host device of the mapping for debug |
5042db43 JG |
101 | * @data: private data pointer for page_free() |
102 | * @type: memory type: see MEMORY_* in memory_hotplug.h | |
514caf23 | 103 | * @flags: PGMAP_* flags to specify defailed behavior |
1e240e8d | 104 | * @ops: method table |
9476df7d DW |
105 | */ |
106 | struct dev_pagemap { | |
e7744aa2 | 107 | struct vmem_altmap altmap; |
e7744aa2 | 108 | struct resource res; |
5c2c2587 | 109 | struct percpu_ref *ref; |
24917f6b CH |
110 | struct percpu_ref internal_ref; |
111 | struct completion done; | |
9476df7d | 112 | struct device *dev; |
5042db43 | 113 | enum memory_type type; |
514caf23 | 114 | unsigned int flags; |
977196b8 | 115 | u64 pci_p2pdma_bus_offset; |
1e240e8d | 116 | const struct dev_pagemap_ops *ops; |
9476df7d DW |
117 | }; |
118 | ||
514caf23 CH |
119 | static inline struct vmem_altmap *pgmap_altmap(struct dev_pagemap *pgmap) |
120 | { | |
121 | if (pgmap->flags & PGMAP_ALTMAP_VALID) | |
122 | return &pgmap->altmap; | |
123 | return NULL; | |
124 | } | |
125 | ||
9476df7d | 126 | #ifdef CONFIG_ZONE_DEVICE |
e8d51348 | 127 | void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap); |
2e3f139e | 128 | void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap); |
0822acb8 CH |
129 | struct dev_pagemap *get_dev_pagemap(unsigned long pfn, |
130 | struct dev_pagemap *pgmap); | |
7b2d55d2 | 131 | |
8e37d00a CH |
132 | unsigned long vmem_altmap_offset(struct vmem_altmap *altmap); |
133 | void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns); | |
9476df7d DW |
134 | #else |
135 | static inline void *devm_memremap_pages(struct device *dev, | |
e8d51348 | 136 | struct dev_pagemap *pgmap) |
9476df7d DW |
137 | { |
138 | /* | |
139 | * Fail attempts to call devm_memremap_pages() without | |
140 | * ZONE_DEVICE support enabled, this requires callers to fall | |
141 | * back to plain devm_memremap() based on config | |
142 | */ | |
143 | WARN_ON_ONCE(1); | |
144 | return ERR_PTR(-ENXIO); | |
145 | } | |
146 | ||
2e3f139e DW |
147 | static inline void devm_memunmap_pages(struct device *dev, |
148 | struct dev_pagemap *pgmap) | |
149 | { | |
150 | } | |
151 | ||
0822acb8 CH |
152 | static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn, |
153 | struct dev_pagemap *pgmap) | |
9476df7d DW |
154 | { |
155 | return NULL; | |
156 | } | |
8e37d00a CH |
157 | |
158 | static inline unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) | |
159 | { | |
160 | return 0; | |
161 | } | |
162 | ||
163 | static inline void vmem_altmap_free(struct vmem_altmap *altmap, | |
164 | unsigned long nr_pfns) | |
165 | { | |
166 | } | |
167 | #endif /* CONFIG_ZONE_DEVICE */ | |
7b2d55d2 | 168 | |
5c2c2587 DW |
169 | static inline void put_dev_pagemap(struct dev_pagemap *pgmap) |
170 | { | |
171 | if (pgmap) | |
172 | percpu_ref_put(pgmap->ref); | |
173 | } | |
9476df7d | 174 | #endif /* _LINUX_MEMREMAP_H_ */ |