1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * PowerNV OPAL Powercap interface
4  *
5  * Copyright 2017 IBM Corp.
6  */
7 
8 #define pr_fmt(fmt)     "opal-powercap: " 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(powercap_mutex);
17 
18 static struct kobject *powercap_kobj;
19 
20 struct powercap_attr {
21 	u32 handle;
22 	struct kobj_attribute attr;
23 };
24 
25 static struct pcap {
26 	struct attribute_group pg;
27 	struct powercap_attr *pattrs;
28 } *pcaps;
29 
30 static ssize_t powercap_show(struct kobject *kobj, struct kobj_attribute *attr,
31 			     char *buf)
32 {
33 	struct powercap_attr *pcap_attr = container_of(attr,
34 						struct powercap_attr, attr);
35 	struct opal_msg msg;
36 	u32 pcap;
37 	int ret, token;
38 
39 	token = opal_async_get_token_interruptible();
40 	if (token < 0) {
41 		pr_devel("Failed to get token\n");
42 		return token;
43 	}
44 
45 	ret = mutex_lock_interruptible(&powercap_mutex);
46 	if (ret)
47 		goto out_token;
48 
49 	ret = opal_get_powercap(pcap_attr->handle, token, (u32 *)__pa(&pcap));
50 	switch (ret) {
51 	case OPAL_ASYNC_COMPLETION:
52 		ret = opal_async_wait_response(token, &msg);
53 		if (ret) {
54 			pr_devel("Failed to wait for the async response\n");
55 			ret = -EIO;
56 			goto out;
57 		}
58 		ret = opal_error_code(opal_get_async_rc(msg));
59 		if (!ret) {
60 			ret = sprintf(buf, "%u\n", be32_to_cpu(pcap));
61 			if (ret < 0)
62 				ret = -EIO;
63 		}
64 		break;
65 	case OPAL_SUCCESS:
66 		ret = sprintf(buf, "%u\n", be32_to_cpu(pcap));
67 		if (ret < 0)
68 			ret = -EIO;
69 		break;
70 	default:
71 		ret = opal_error_code(ret);
72 	}
73 
74 out:
75 	mutex_unlock(&powercap_mutex);
76 out_token:
77 	opal_async_release_token(token);
78 	return ret;
79 }
80 
81 static ssize_t powercap_store(struct kobject *kobj,
82 			      struct kobj_attribute *attr, const char *buf,
83 			      size_t count)
84 {
85 	struct powercap_attr *pcap_attr = container_of(attr,
86 						struct powercap_attr, attr);
87 	struct opal_msg msg;
88 	u32 pcap;
89 	int ret, token;
90 
91 	ret = kstrtoint(buf, 0, &pcap);
92 	if (ret)
93 		return ret;
94 
95 	token = opal_async_get_token_interruptible();
96 	if (token < 0) {
97 		pr_devel("Failed to get token\n");
98 		return token;
99 	}
100 
101 	ret = mutex_lock_interruptible(&powercap_mutex);
102 	if (ret)
103 		goto out_token;
104 
105 	ret = opal_set_powercap(pcap_attr->handle, token, pcap);
106 	switch (ret) {
107 	case OPAL_ASYNC_COMPLETION:
108 		ret = opal_async_wait_response(token, &msg);
109 		if (ret) {
110 			pr_devel("Failed to wait for the async response\n");
111 			ret = -EIO;
112 			goto out;
113 		}
114 		ret = opal_error_code(opal_get_async_rc(msg));
115 		if (!ret)
116 			ret = count;
117 		break;
118 	case OPAL_SUCCESS:
119 		ret = count;
120 		break;
121 	default:
122 		ret = opal_error_code(ret);
123 	}
124 
125 out:
126 	mutex_unlock(&powercap_mutex);
127 out_token:
128 	opal_async_release_token(token);
129 	return ret;
130 }
131 
132 static void powercap_add_attr(int handle, const char *name,
133 			      struct powercap_attr *attr)
134 {
135 	attr->handle = handle;
136 	sysfs_attr_init(&attr->attr.attr);
137 	attr->attr.attr.name = name;
138 	attr->attr.attr.mode = 0444;
139 	attr->attr.show = powercap_show;
140 }
141 
142 void __init opal_powercap_init(void)
143 {
144 	struct device_node *powercap, *node;
145 	int i = 0;
146 
147 	powercap = of_find_compatible_node(NULL, NULL, "ibm,opal-powercap");
148 	if (!powercap) {
149 		pr_devel("Powercap node not found\n");
150 		return;
151 	}
152 
153 	pcaps = kcalloc(of_get_child_count(powercap), sizeof(*pcaps),
154 			GFP_KERNEL);
155 	if (!pcaps)
156 		return;
157 
158 	powercap_kobj = kobject_create_and_add("powercap", opal_kobj);
159 	if (!powercap_kobj) {
160 		pr_warn("Failed to create powercap kobject\n");
161 		goto out_pcaps;
162 	}
163 
164 	i = 0;
165 	for_each_child_of_node(powercap, node) {
166 		u32 cur, min, max;
167 		int j = 0;
168 		bool has_cur = false, has_min = false, has_max = false;
169 
170 		if (!of_property_read_u32(node, "powercap-min", &min)) {
171 			j++;
172 			has_min = true;
173 		}
174 
175 		if (!of_property_read_u32(node, "powercap-max", &max)) {
176 			j++;
177 			has_max = true;
178 		}
179 
180 		if (!of_property_read_u32(node, "powercap-current", &cur)) {
181 			j++;
182 			has_cur = true;
183 		}
184 
185 		pcaps[i].pattrs = kcalloc(j, sizeof(struct powercap_attr),
186 					  GFP_KERNEL);
187 		if (!pcaps[i].pattrs)
188 			goto out_pcaps_pattrs;
189 
190 		pcaps[i].pg.attrs = kcalloc(j + 1, sizeof(struct attribute *),
191 					    GFP_KERNEL);
192 		if (!pcaps[i].pg.attrs) {
193 			kfree(pcaps[i].pattrs);
194 			goto out_pcaps_pattrs;
195 		}
196 
197 		j = 0;
198 		pcaps[i].pg.name = kasprintf(GFP_KERNEL, "%pOFn", node);
199 		if (has_min) {
200 			powercap_add_attr(min, "powercap-min",
201 					  &pcaps[i].pattrs[j]);
202 			pcaps[i].pg.attrs[j] = &pcaps[i].pattrs[j].attr.attr;
203 			j++;
204 		}
205 
206 		if (has_max) {
207 			powercap_add_attr(max, "powercap-max",
208 					  &pcaps[i].pattrs[j]);
209 			pcaps[i].pg.attrs[j] = &pcaps[i].pattrs[j].attr.attr;
210 			j++;
211 		}
212 
213 		if (has_cur) {
214 			powercap_add_attr(cur, "powercap-current",
215 					  &pcaps[i].pattrs[j]);
216 			pcaps[i].pattrs[j].attr.attr.mode |= 0220;
217 			pcaps[i].pattrs[j].attr.store = powercap_store;
218 			pcaps[i].pg.attrs[j] = &pcaps[i].pattrs[j].attr.attr;
219 			j++;
220 		}
221 
222 		if (sysfs_create_group(powercap_kobj, &pcaps[i].pg)) {
223 			pr_warn("Failed to create powercap attribute group %s\n",
224 				pcaps[i].pg.name);
225 			goto out_pcaps_pattrs;
226 		}
227 		i++;
228 	}
229 
230 	return;
231 
232 out_pcaps_pattrs:
233 	while (--i >= 0) {
234 		kfree(pcaps[i].pattrs);
235 		kfree(pcaps[i].pg.attrs);
236 		kfree(pcaps[i].pg.name);
237 	}
238 	kobject_put(powercap_kobj);
239 out_pcaps:
240 	kfree(pcaps);
241 }
242