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 static DEFINE_MUTEX(psr_mutex);
17
18 static struct kobject *psr_kobj;
19
20 static struct psr_attr {
21 u32 handle;
22 struct kobj_attribute attr;
23 } *psr_attrs;
24
psr_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)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
psr_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)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
opal_psr_init(void)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 goto out_put_psr;
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 of_node_put(psr);
166
167 return;
168 out_kobj:
169 of_node_put(node);
170 kobject_put(psr_kobj);
171 out:
172 kfree(psr_attrs);
173 out_put_psr:
174 of_node_put(psr);
175 }
176