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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 JG |
39 | * |
40 | * MEMORY_DEVICE_PUBLIC: | |
41 | * Device memory that is cache coherent from device and CPU point of view. This | |
42 | * is use on platform that have an advance system bus (like CAPI or CCIX). A | |
43 | * driver can hotplug the device memory using ZONE_DEVICE and with that memory | |
44 | * type. Any page of a process can be migrated to such memory. However no one | |
45 | * should be allow to pin such memory so that it can always be evicted. | |
e7638488 DW |
46 | * |
47 | * MEMORY_DEVICE_FS_DAX: | |
48 | * Host memory that has similar access semantics as System RAM i.e. DMA | |
49 | * coherent and supports page pinning. In support of coordinating page | |
50 | * pinning vs other operations MEMORY_DEVICE_FS_DAX arranges for a | |
51 | * wakeup event whenever a page is unpinned and becomes idle. This | |
52 | * wakeup is used to coordinate physical address space management (ex: | |
53 | * fs truncate/hole punch) vs pinned pages (ex: device dma). | |
52916982 LG |
54 | * |
55 | * MEMORY_DEVICE_PCI_P2PDMA: | |
56 | * Device memory residing in a PCI BAR intended for use with Peer-to-Peer | |
57 | * transactions. | |
5042db43 JG |
58 | */ |
59 | enum memory_type { | |
e7638488 | 60 | MEMORY_DEVICE_PRIVATE = 1, |
df6ad698 | 61 | MEMORY_DEVICE_PUBLIC, |
e7638488 | 62 | MEMORY_DEVICE_FS_DAX, |
52916982 | 63 | MEMORY_DEVICE_PCI_P2PDMA, |
5042db43 JG |
64 | }; |
65 | ||
66 | /* | |
5042db43 | 67 | * Additional notes about MEMORY_DEVICE_PRIVATE may be found in |
ad56b738 | 68 | * include/linux/hmm.h and Documentation/vm/hmm.rst. There is also a brief |
5042db43 JG |
69 | * explanation in include/linux/memory_hotplug.h. |
70 | * | |
5042db43 JG |
71 | * The page_free() callback is called once the page refcount reaches 1 |
72 | * (ZONE_DEVICE pages never reach 0 refcount unless there is a refcount bug. | |
73 | * This allows the device driver to implement its own memory management.) | |
74 | */ | |
5042db43 JG |
75 | typedef void (*dev_page_free_t)(struct page *page, void *data); |
76 | ||
9476df7d DW |
77 | /** |
78 | * struct dev_pagemap - metadata for ZONE_DEVICE mappings | |
5042db43 | 79 | * @page_free: free page callback when page refcount reaches 1 |
4b94ffdc | 80 | * @altmap: pre-allocated/reserved memory for vmemmap allocations |
5c2c2587 DW |
81 | * @res: physical address range covered by @ref |
82 | * @ref: reference count that pins the devm_memremap_pages() mapping | |
a95c90f1 | 83 | * @kill: callback to transition @ref to the dead state |
50f44ee7 | 84 | * @cleanup: callback to wait for @ref to be idle and reap it |
9476df7d | 85 | * @dev: host device of the mapping for debug |
5042db43 JG |
86 | * @data: private data pointer for page_free() |
87 | * @type: memory type: see MEMORY_* in memory_hotplug.h | |
9476df7d DW |
88 | */ |
89 | struct dev_pagemap { | |
5042db43 | 90 | dev_page_free_t page_free; |
e7744aa2 LG |
91 | struct vmem_altmap altmap; |
92 | bool altmap_valid; | |
93 | struct resource res; | |
5c2c2587 | 94 | struct percpu_ref *ref; |
a95c90f1 | 95 | void (*kill)(struct percpu_ref *ref); |
50f44ee7 | 96 | void (*cleanup)(struct percpu_ref *ref); |
9476df7d | 97 | struct device *dev; |
5042db43 JG |
98 | void *data; |
99 | enum memory_type type; | |
977196b8 | 100 | u64 pci_p2pdma_bus_offset; |
9476df7d DW |
101 | }; |
102 | ||
103 | #ifdef CONFIG_ZONE_DEVICE | |
e8d51348 | 104 | void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap); |
2e3f139e | 105 | void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap); |
0822acb8 CH |
106 | struct dev_pagemap *get_dev_pagemap(unsigned long pfn, |
107 | struct dev_pagemap *pgmap); | |
7b2d55d2 | 108 | |
8e37d00a CH |
109 | unsigned long vmem_altmap_offset(struct vmem_altmap *altmap); |
110 | void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns); | |
9476df7d DW |
111 | #else |
112 | static inline void *devm_memremap_pages(struct device *dev, | |
e8d51348 | 113 | struct dev_pagemap *pgmap) |
9476df7d DW |
114 | { |
115 | /* | |
116 | * Fail attempts to call devm_memremap_pages() without | |
117 | * ZONE_DEVICE support enabled, this requires callers to fall | |
118 | * back to plain devm_memremap() based on config | |
119 | */ | |
120 | WARN_ON_ONCE(1); | |
121 | return ERR_PTR(-ENXIO); | |
122 | } | |
123 | ||
2e3f139e DW |
124 | static inline void devm_memunmap_pages(struct device *dev, |
125 | struct dev_pagemap *pgmap) | |
126 | { | |
127 | } | |
128 | ||
0822acb8 CH |
129 | static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn, |
130 | struct dev_pagemap *pgmap) | |
9476df7d DW |
131 | { |
132 | return NULL; | |
133 | } | |
8e37d00a CH |
134 | |
135 | static inline unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) | |
136 | { | |
137 | return 0; | |
138 | } | |
139 | ||
140 | static inline void vmem_altmap_free(struct vmem_altmap *altmap, | |
141 | unsigned long nr_pfns) | |
142 | { | |
143 | } | |
144 | #endif /* CONFIG_ZONE_DEVICE */ | |
7b2d55d2 | 145 | |
5c2c2587 DW |
146 | static inline void put_dev_pagemap(struct dev_pagemap *pgmap) |
147 | { | |
148 | if (pgmap) | |
149 | percpu_ref_put(pgmap->ref); | |
150 | } | |
9476df7d | 151 | #endif /* _LINUX_MEMREMAP_H_ */ |