Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * Copyright 2014 IBM Corp.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 */
9
10#include <linux/module.h>
11#include <linux/rcupdate.h>
12#include <asm/errno.h>
13#include <misc/cxl-base.h>
14#include <linux/of_platform.h>
15#include "cxl.h"
16
17/* protected by rcu */
18static struct cxl_calls *cxl_calls;
19
20atomic_t cxl_use_count = ATOMIC_INIT(0);
21EXPORT_SYMBOL(cxl_use_count);
22
23#ifdef CONFIG_CXL_MODULE
24
25static inline struct cxl_calls *cxl_calls_get(void)
26{
27 struct cxl_calls *calls = NULL;
28
29 rcu_read_lock();
30 calls = rcu_dereference(cxl_calls);
31 if (calls && !try_module_get(calls->owner))
32 calls = NULL;
33 rcu_read_unlock();
34
35 return calls;
36}
37
38static inline void cxl_calls_put(struct cxl_calls *calls)
39{
40 BUG_ON(calls != cxl_calls);
41
42 /* we don't need to rcu this, as we hold a reference to the module */
43 module_put(cxl_calls->owner);
44}
45
46#else /* !defined CONFIG_CXL_MODULE */
47
48static inline struct cxl_calls *cxl_calls_get(void)
49{
50 return cxl_calls;
51}
52
53static inline void cxl_calls_put(struct cxl_calls *calls) { }
54
55#endif /* CONFIG_CXL_MODULE */
56
57/* AFU refcount management */
58struct cxl_afu *cxl_afu_get(struct cxl_afu *afu)
59{
60 return (get_device(&afu->dev) == NULL) ? NULL : afu;
61}
62EXPORT_SYMBOL_GPL(cxl_afu_get);
63
64void cxl_afu_put(struct cxl_afu *afu)
65{
66 put_device(&afu->dev);
67}
68EXPORT_SYMBOL_GPL(cxl_afu_put);
69
70void cxl_slbia(struct mm_struct *mm)
71{
72 struct cxl_calls *calls;
73
74 calls = cxl_calls_get();
75 if (!calls)
76 return;
77
78 if (cxl_ctx_in_use())
79 calls->cxl_slbia(mm);
80
81 cxl_calls_put(calls);
82}
83
84int register_cxl_calls(struct cxl_calls *calls)
85{
86 if (cxl_calls)
87 return -EBUSY;
88
89 rcu_assign_pointer(cxl_calls, calls);
90 return 0;
91}
92EXPORT_SYMBOL_GPL(register_cxl_calls);
93
94void unregister_cxl_calls(struct cxl_calls *calls)
95{
96 BUG_ON(cxl_calls->owner != calls->owner);
97 RCU_INIT_POINTER(cxl_calls, NULL);
98 synchronize_rcu();
99}
100EXPORT_SYMBOL_GPL(unregister_cxl_calls);
101
102int cxl_update_properties(struct device_node *dn,
103 struct property *new_prop)
104{
105 return of_update_property(dn, new_prop);
106}
107EXPORT_SYMBOL_GPL(cxl_update_properties);
108
109static int __init cxl_base_init(void)
110{
111 struct device_node *np;
112 struct platform_device *dev;
113 int count = 0;
114
115 /*
116 * Scan for compatible devices in guest only
117 */
118 if (cpu_has_feature(CPU_FTR_HVMODE))
119 return 0;
120
121 for_each_compatible_node(np, NULL, "ibm,coherent-platform-facility") {
122 dev = of_platform_device_create(np, NULL, NULL);
123 if (dev)
124 count++;
125 }
126 pr_devel("Found %d cxl device(s)\n", count);
127 return 0;
128}
129device_initcall(cxl_base_init);