1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-or-later
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Copyright 2014 IBM Corp.
4*4882a593Smuzhiyun */
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun #include <linux/module.h>
7*4882a593Smuzhiyun #include <linux/rcupdate.h>
8*4882a593Smuzhiyun #include <asm/errno.h>
9*4882a593Smuzhiyun #include <misc/cxl-base.h>
10*4882a593Smuzhiyun #include <linux/of_platform.h>
11*4882a593Smuzhiyun #include "cxl.h"
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun /* protected by rcu */
14*4882a593Smuzhiyun static struct cxl_calls *cxl_calls;
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun atomic_t cxl_use_count = ATOMIC_INIT(0);
17*4882a593Smuzhiyun EXPORT_SYMBOL(cxl_use_count);
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun #ifdef CONFIG_CXL_MODULE
20*4882a593Smuzhiyun
cxl_calls_get(void)21*4882a593Smuzhiyun static inline struct cxl_calls *cxl_calls_get(void)
22*4882a593Smuzhiyun {
23*4882a593Smuzhiyun struct cxl_calls *calls = NULL;
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun rcu_read_lock();
26*4882a593Smuzhiyun calls = rcu_dereference(cxl_calls);
27*4882a593Smuzhiyun if (calls && !try_module_get(calls->owner))
28*4882a593Smuzhiyun calls = NULL;
29*4882a593Smuzhiyun rcu_read_unlock();
30*4882a593Smuzhiyun
31*4882a593Smuzhiyun return calls;
32*4882a593Smuzhiyun }
33*4882a593Smuzhiyun
cxl_calls_put(struct cxl_calls * calls)34*4882a593Smuzhiyun static inline void cxl_calls_put(struct cxl_calls *calls)
35*4882a593Smuzhiyun {
36*4882a593Smuzhiyun BUG_ON(calls != cxl_calls);
37*4882a593Smuzhiyun
38*4882a593Smuzhiyun /* we don't need to rcu this, as we hold a reference to the module */
39*4882a593Smuzhiyun module_put(cxl_calls->owner);
40*4882a593Smuzhiyun }
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun #else /* !defined CONFIG_CXL_MODULE */
43*4882a593Smuzhiyun
cxl_calls_get(void)44*4882a593Smuzhiyun static inline struct cxl_calls *cxl_calls_get(void)
45*4882a593Smuzhiyun {
46*4882a593Smuzhiyun return cxl_calls;
47*4882a593Smuzhiyun }
48*4882a593Smuzhiyun
cxl_calls_put(struct cxl_calls * calls)49*4882a593Smuzhiyun static inline void cxl_calls_put(struct cxl_calls *calls) { }
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun #endif /* CONFIG_CXL_MODULE */
52*4882a593Smuzhiyun
53*4882a593Smuzhiyun /* AFU refcount management */
cxl_afu_get(struct cxl_afu * afu)54*4882a593Smuzhiyun struct cxl_afu *cxl_afu_get(struct cxl_afu *afu)
55*4882a593Smuzhiyun {
56*4882a593Smuzhiyun return (get_device(&afu->dev) == NULL) ? NULL : afu;
57*4882a593Smuzhiyun }
58*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(cxl_afu_get);
59*4882a593Smuzhiyun
cxl_afu_put(struct cxl_afu * afu)60*4882a593Smuzhiyun void cxl_afu_put(struct cxl_afu *afu)
61*4882a593Smuzhiyun {
62*4882a593Smuzhiyun put_device(&afu->dev);
63*4882a593Smuzhiyun }
64*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(cxl_afu_put);
65*4882a593Smuzhiyun
cxl_slbia(struct mm_struct * mm)66*4882a593Smuzhiyun void cxl_slbia(struct mm_struct *mm)
67*4882a593Smuzhiyun {
68*4882a593Smuzhiyun struct cxl_calls *calls;
69*4882a593Smuzhiyun
70*4882a593Smuzhiyun calls = cxl_calls_get();
71*4882a593Smuzhiyun if (!calls)
72*4882a593Smuzhiyun return;
73*4882a593Smuzhiyun
74*4882a593Smuzhiyun if (cxl_ctx_in_use())
75*4882a593Smuzhiyun calls->cxl_slbia(mm);
76*4882a593Smuzhiyun
77*4882a593Smuzhiyun cxl_calls_put(calls);
78*4882a593Smuzhiyun }
79*4882a593Smuzhiyun
register_cxl_calls(struct cxl_calls * calls)80*4882a593Smuzhiyun int register_cxl_calls(struct cxl_calls *calls)
81*4882a593Smuzhiyun {
82*4882a593Smuzhiyun if (cxl_calls)
83*4882a593Smuzhiyun return -EBUSY;
84*4882a593Smuzhiyun
85*4882a593Smuzhiyun rcu_assign_pointer(cxl_calls, calls);
86*4882a593Smuzhiyun return 0;
87*4882a593Smuzhiyun }
88*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(register_cxl_calls);
89*4882a593Smuzhiyun
unregister_cxl_calls(struct cxl_calls * calls)90*4882a593Smuzhiyun void unregister_cxl_calls(struct cxl_calls *calls)
91*4882a593Smuzhiyun {
92*4882a593Smuzhiyun BUG_ON(cxl_calls->owner != calls->owner);
93*4882a593Smuzhiyun RCU_INIT_POINTER(cxl_calls, NULL);
94*4882a593Smuzhiyun synchronize_rcu();
95*4882a593Smuzhiyun }
96*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(unregister_cxl_calls);
97*4882a593Smuzhiyun
cxl_update_properties(struct device_node * dn,struct property * new_prop)98*4882a593Smuzhiyun int cxl_update_properties(struct device_node *dn,
99*4882a593Smuzhiyun struct property *new_prop)
100*4882a593Smuzhiyun {
101*4882a593Smuzhiyun return of_update_property(dn, new_prop);
102*4882a593Smuzhiyun }
103*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(cxl_update_properties);
104*4882a593Smuzhiyun
cxl_base_init(void)105*4882a593Smuzhiyun static int __init cxl_base_init(void)
106*4882a593Smuzhiyun {
107*4882a593Smuzhiyun struct device_node *np;
108*4882a593Smuzhiyun struct platform_device *dev;
109*4882a593Smuzhiyun int count = 0;
110*4882a593Smuzhiyun
111*4882a593Smuzhiyun /*
112*4882a593Smuzhiyun * Scan for compatible devices in guest only
113*4882a593Smuzhiyun */
114*4882a593Smuzhiyun if (cpu_has_feature(CPU_FTR_HVMODE))
115*4882a593Smuzhiyun return 0;
116*4882a593Smuzhiyun
117*4882a593Smuzhiyun for_each_compatible_node(np, NULL, "ibm,coherent-platform-facility") {
118*4882a593Smuzhiyun dev = of_platform_device_create(np, NULL, NULL);
119*4882a593Smuzhiyun if (dev)
120*4882a593Smuzhiyun count++;
121*4882a593Smuzhiyun }
122*4882a593Smuzhiyun pr_devel("Found %d cxl device(s)\n", count);
123*4882a593Smuzhiyun return 0;
124*4882a593Smuzhiyun }
125*4882a593Smuzhiyun device_initcall(cxl_base_init);
126