1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright 2014 IBM Corp.
4 */
5
6 #include <linux/module.h>
7 #include <linux/rcupdate.h>
8 #include <asm/errno.h>
9 #include <misc/cxl-base.h>
10 #include <linux/of.h>
11 #include <linux/of_platform.h>
12 #include "cxl.h"
13
14 /* protected by rcu */
15 static struct cxl_calls *cxl_calls;
16
17 atomic_t cxl_use_count = ATOMIC_INIT(0);
18 EXPORT_SYMBOL(cxl_use_count);
19
20 #ifdef CONFIG_CXL_MODULE
21
cxl_calls_get(void)22 static inline struct cxl_calls *cxl_calls_get(void)
23 {
24 struct cxl_calls *calls = NULL;
25
26 rcu_read_lock();
27 calls = rcu_dereference(cxl_calls);
28 if (calls && !try_module_get(calls->owner))
29 calls = NULL;
30 rcu_read_unlock();
31
32 return calls;
33 }
34
cxl_calls_put(struct cxl_calls * calls)35 static inline void cxl_calls_put(struct cxl_calls *calls)
36 {
37 BUG_ON(calls != cxl_calls);
38
39 /* we don't need to rcu this, as we hold a reference to the module */
40 module_put(cxl_calls->owner);
41 }
42
43 #else /* !defined CONFIG_CXL_MODULE */
44
cxl_calls_get(void)45 static inline struct cxl_calls *cxl_calls_get(void)
46 {
47 return cxl_calls;
48 }
49
cxl_calls_put(struct cxl_calls * calls)50 static inline void cxl_calls_put(struct cxl_calls *calls) { }
51
52 #endif /* CONFIG_CXL_MODULE */
53
54 /* AFU refcount management */
cxl_afu_get(struct cxl_afu * afu)55 struct cxl_afu *cxl_afu_get(struct cxl_afu *afu)
56 {
57 return (get_device(&afu->dev) == NULL) ? NULL : afu;
58 }
59 EXPORT_SYMBOL_GPL(cxl_afu_get);
60
cxl_afu_put(struct cxl_afu * afu)61 void cxl_afu_put(struct cxl_afu *afu)
62 {
63 put_device(&afu->dev);
64 }
65 EXPORT_SYMBOL_GPL(cxl_afu_put);
66
cxl_slbia(struct mm_struct * mm)67 void cxl_slbia(struct mm_struct *mm)
68 {
69 struct cxl_calls *calls;
70
71 calls = cxl_calls_get();
72 if (!calls)
73 return;
74
75 if (cxl_ctx_in_use())
76 calls->cxl_slbia(mm);
77
78 cxl_calls_put(calls);
79 }
80
register_cxl_calls(struct cxl_calls * calls)81 int register_cxl_calls(struct cxl_calls *calls)
82 {
83 if (cxl_calls)
84 return -EBUSY;
85
86 rcu_assign_pointer(cxl_calls, calls);
87 return 0;
88 }
89 EXPORT_SYMBOL_GPL(register_cxl_calls);
90
unregister_cxl_calls(struct cxl_calls * calls)91 void unregister_cxl_calls(struct cxl_calls *calls)
92 {
93 BUG_ON(cxl_calls->owner != calls->owner);
94 RCU_INIT_POINTER(cxl_calls, NULL);
95 synchronize_rcu();
96 }
97 EXPORT_SYMBOL_GPL(unregister_cxl_calls);
98
cxl_update_properties(struct device_node * dn,struct property * new_prop)99 int cxl_update_properties(struct device_node *dn,
100 struct property *new_prop)
101 {
102 return of_update_property(dn, new_prop);
103 }
104 EXPORT_SYMBOL_GPL(cxl_update_properties);
105
cxl_base_init(void)106 static int __init cxl_base_init(void)
107 {
108 struct device_node *np;
109 struct platform_device *dev;
110 int count = 0;
111
112 /*
113 * Scan for compatible devices in guest only
114 */
115 if (cpu_has_feature(CPU_FTR_HVMODE))
116 return 0;
117
118 for_each_compatible_node(np, NULL, "ibm,coherent-platform-facility") {
119 dev = of_platform_device_create(np, NULL, NULL);
120 if (dev)
121 count++;
122 }
123 pr_devel("Found %d cxl device(s)\n", count);
124 return 0;
125 }
126 device_initcall(cxl_base_init);
127