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1 | // SPDX-License-Identifier: GPL-2.0-or-later | |
2 | /* | |
3 | * PowerNV OPAL Power-Shift-Ratio interface | |
4 | * | |
5 | * Copyright 2017 IBM Corp. | |
6 | */ | |
7 | ||
8 | #define pr_fmt(fmt) "opal-psr: " fmt | |
9 | ||
10 | #include <linux/of.h> | |
11 | #include <linux/kobject.h> | |
12 | #include <linux/slab.h> | |
13 | ||
14 | #include <asm/opal.h> | |
15 | ||
16 | DEFINE_MUTEX(psr_mutex); | |
17 | ||
18 | static struct kobject *psr_kobj; | |
19 | ||
20 | struct psr_attr { | |
21 | u32 handle; | |
22 | struct kobj_attribute attr; | |
23 | } *psr_attrs; | |
24 | ||
25 | static ssize_t psr_show(struct kobject *kobj, struct kobj_attribute *attr, | |
26 | char *buf) | |
27 | { | |
28 | struct psr_attr *psr_attr = container_of(attr, struct psr_attr, attr); | |
29 | struct opal_msg msg; | |
30 | int psr, ret, token; | |
31 | ||
32 | token = opal_async_get_token_interruptible(); | |
33 | if (token < 0) { | |
34 | pr_devel("Failed to get token\n"); | |
35 | return token; | |
36 | } | |
37 | ||
38 | ret = mutex_lock_interruptible(&psr_mutex); | |
39 | if (ret) | |
40 | goto out_token; | |
41 | ||
42 | ret = opal_get_power_shift_ratio(psr_attr->handle, token, | |
43 | (u32 *)__pa(&psr)); | |
44 | switch (ret) { | |
45 | case OPAL_ASYNC_COMPLETION: | |
46 | ret = opal_async_wait_response(token, &msg); | |
47 | if (ret) { | |
48 | pr_devel("Failed to wait for the async response\n"); | |
49 | ret = -EIO; | |
50 | goto out; | |
51 | } | |
52 | ret = opal_error_code(opal_get_async_rc(msg)); | |
53 | if (!ret) { | |
54 | ret = sprintf(buf, "%u\n", be32_to_cpu(psr)); | |
55 | if (ret < 0) | |
56 | ret = -EIO; | |
57 | } | |
58 | break; | |
59 | case OPAL_SUCCESS: | |
60 | ret = sprintf(buf, "%u\n", be32_to_cpu(psr)); | |
61 | if (ret < 0) | |
62 | ret = -EIO; | |
63 | break; | |
64 | default: | |
65 | ret = opal_error_code(ret); | |
66 | } | |
67 | ||
68 | out: | |
69 | mutex_unlock(&psr_mutex); | |
70 | out_token: | |
71 | opal_async_release_token(token); | |
72 | return ret; | |
73 | } | |
74 | ||
75 | static ssize_t psr_store(struct kobject *kobj, struct kobj_attribute *attr, | |
76 | const char *buf, size_t count) | |
77 | { | |
78 | struct psr_attr *psr_attr = container_of(attr, struct psr_attr, attr); | |
79 | struct opal_msg msg; | |
80 | int psr, ret, token; | |
81 | ||
82 | ret = kstrtoint(buf, 0, &psr); | |
83 | if (ret) | |
84 | return ret; | |
85 | ||
86 | token = opal_async_get_token_interruptible(); | |
87 | if (token < 0) { | |
88 | pr_devel("Failed to get token\n"); | |
89 | return token; | |
90 | } | |
91 | ||
92 | ret = mutex_lock_interruptible(&psr_mutex); | |
93 | if (ret) | |
94 | goto out_token; | |
95 | ||
96 | ret = opal_set_power_shift_ratio(psr_attr->handle, token, psr); | |
97 | switch (ret) { | |
98 | case OPAL_ASYNC_COMPLETION: | |
99 | ret = opal_async_wait_response(token, &msg); | |
100 | if (ret) { | |
101 | pr_devel("Failed to wait for the async response\n"); | |
102 | ret = -EIO; | |
103 | goto out; | |
104 | } | |
105 | ret = opal_error_code(opal_get_async_rc(msg)); | |
106 | if (!ret) | |
107 | ret = count; | |
108 | break; | |
109 | case OPAL_SUCCESS: | |
110 | ret = count; | |
111 | break; | |
112 | default: | |
113 | ret = opal_error_code(ret); | |
114 | } | |
115 | ||
116 | out: | |
117 | mutex_unlock(&psr_mutex); | |
118 | out_token: | |
119 | opal_async_release_token(token); | |
120 | return ret; | |
121 | } | |
122 | ||
123 | void __init opal_psr_init(void) | |
124 | { | |
125 | struct device_node *psr, *node; | |
126 | int i = 0; | |
127 | ||
128 | psr = of_find_compatible_node(NULL, NULL, | |
129 | "ibm,opal-power-shift-ratio"); | |
130 | if (!psr) { | |
131 | pr_devel("Power-shift-ratio node not found\n"); | |
132 | return; | |
133 | } | |
134 | ||
135 | psr_attrs = kcalloc(of_get_child_count(psr), sizeof(*psr_attrs), | |
136 | GFP_KERNEL); | |
137 | if (!psr_attrs) | |
138 | return; | |
139 | ||
140 | psr_kobj = kobject_create_and_add("psr", opal_kobj); | |
141 | if (!psr_kobj) { | |
142 | pr_warn("Failed to create psr kobject\n"); | |
143 | goto out; | |
144 | } | |
145 | ||
146 | for_each_child_of_node(psr, node) { | |
147 | if (of_property_read_u32(node, "handle", | |
148 | &psr_attrs[i].handle)) | |
149 | goto out_kobj; | |
150 | ||
151 | sysfs_attr_init(&psr_attrs[i].attr.attr); | |
152 | if (of_property_read_string(node, "label", | |
153 | &psr_attrs[i].attr.attr.name)) | |
154 | goto out_kobj; | |
155 | psr_attrs[i].attr.attr.mode = 0664; | |
156 | psr_attrs[i].attr.show = psr_show; | |
157 | psr_attrs[i].attr.store = psr_store; | |
158 | if (sysfs_create_file(psr_kobj, &psr_attrs[i].attr.attr)) { | |
159 | pr_devel("Failed to create psr sysfs file %s\n", | |
160 | psr_attrs[i].attr.attr.name); | |
161 | goto out_kobj; | |
162 | } | |
163 | i++; | |
164 | } | |
165 | ||
166 | return; | |
167 | out_kobj: | |
168 | kobject_put(psr_kobj); | |
169 | out: | |
170 | kfree(psr_attrs); | |
171 | } |