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