1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Platform energy and frequency attributes driver
4 *
5 * This driver creates a sys file at /sys/firmware/papr/ which encapsulates a
6 * directory structure containing files in keyword - value pairs that specify
7 * energy and frequency configuration of the system.
8 *
9 * The format of exposing the sysfs information is as follows:
10 * /sys/firmware/papr/energy_scale_info/
11 * |-- <id>/
12 * |-- desc
13 * |-- value
14 * |-- value_desc (if exists)
15 * |-- <id>/
16 * |-- desc
17 * |-- value
18 * |-- value_desc (if exists)
19 *
20 * Copyright 2022 IBM Corp.
21 */
22
23 #include <asm/hvcall.h>
24 #include <asm/machdep.h>
25 #include <asm/firmware.h>
26
27 #include "pseries.h"
28
29 /*
30 * Flag attributes to fetch either all or one attribute from the HCALL
31 * flag = BE(0) => fetch all attributes with firstAttributeId = 0
32 * flag = BE(1) => fetch a single attribute with firstAttributeId = id
33 */
34 #define ESI_FLAGS_ALL 0
35 #define ESI_FLAGS_SINGLE (1ull << 63)
36
37 #define KOBJ_MAX_ATTRS 3
38
39 #define ESI_HDR_SIZE sizeof(struct h_energy_scale_info_hdr)
40 #define ESI_ATTR_SIZE sizeof(struct energy_scale_attribute)
41 #define CURR_MAX_ESI_ATTRS 8
42
43 struct energy_scale_attribute {
44 __be64 id;
45 __be64 val;
46 u8 desc[64];
47 u8 value_desc[64];
48 } __packed;
49
50 struct h_energy_scale_info_hdr {
51 __be64 num_attrs;
52 __be64 array_offset;
53 u8 data_header_version;
54 } __packed;
55
56 struct papr_attr {
57 u64 id;
58 struct kobj_attribute kobj_attr;
59 };
60
61 struct papr_group {
62 struct attribute_group pg;
63 struct papr_attr pgattrs[KOBJ_MAX_ATTRS];
64 };
65
66 static struct papr_group *papr_groups;
67 /* /sys/firmware/papr */
68 static struct kobject *papr_kobj;
69 /* /sys/firmware/papr/energy_scale_info */
70 static struct kobject *esi_kobj;
71
72 /*
73 * Energy modes can change dynamically hence making a new hcall each time the
74 * information needs to be retrieved
75 */
76 static int papr_get_attr(u64 id, struct energy_scale_attribute *esi)
77 {
78 int esi_buf_size = ESI_HDR_SIZE + (CURR_MAX_ESI_ATTRS * ESI_ATTR_SIZE);
79 int ret, max_esi_attrs = CURR_MAX_ESI_ATTRS;
80 struct energy_scale_attribute *curr_esi;
81 struct h_energy_scale_info_hdr *hdr;
82 char *buf;
83
84 buf = kmalloc(esi_buf_size, GFP_KERNEL);
85 if (buf == NULL)
86 return -ENOMEM;
87
88 retry:
89 ret = plpar_hcall_norets(H_GET_ENERGY_SCALE_INFO, ESI_FLAGS_SINGLE,
90 id, virt_to_phys(buf),
91 esi_buf_size);
92
93 /*
94 * If the hcall fails with not enough memory for either the
95 * header or data, attempt to allocate more
96 */
97 if (ret == H_PARTIAL || ret == H_P4) {
98 char *temp_buf;
99
100 max_esi_attrs += 4;
101 esi_buf_size = ESI_HDR_SIZE + (CURR_MAX_ESI_ATTRS * max_esi_attrs);
102
103 temp_buf = krealloc(buf, esi_buf_size, GFP_KERNEL);
104 if (temp_buf) {
105 buf = temp_buf;
106 } else {
107 ret = -ENOMEM;
108 goto out_buf;
109 }
110
111 goto retry;
112 }
113
114 if (ret != H_SUCCESS) {
115 pr_warn("hcall failed: H_GET_ENERGY_SCALE_INFO");
116 ret = -EIO;
117 goto out_buf;
118 }
119
120 hdr = (struct h_energy_scale_info_hdr *) buf;
121 curr_esi = (struct energy_scale_attribute *)
122 (buf + be64_to_cpu(hdr->array_offset));
123
124 if (esi_buf_size <
125 be64_to_cpu(hdr->array_offset) + (be64_to_cpu(hdr->num_attrs)
126 * sizeof(struct energy_scale_attribute))) {
127 ret = -EIO;
128 goto out_buf;
129 }
130
131 *esi = *curr_esi;
132
133 out_buf:
134 kfree(buf);
135
136 return ret;
137 }
138
139 /*
140 * Extract and export the description of the energy scale attributes
141 */
142 static ssize_t desc_show(struct kobject *kobj,
143 struct kobj_attribute *kobj_attr,
144 char *buf)
145 {
146 struct papr_attr *pattr = container_of(kobj_attr, struct papr_attr,
147 kobj_attr);
148 struct energy_scale_attribute esi;
149 int ret;
150
151 ret = papr_get_attr(pattr->id, &esi);
152 if (ret)
153 return ret;
154
155 return sysfs_emit(buf, "%s\n", esi.desc);
156 }
157
158 /*
159 * Extract and export the numeric value of the energy scale attributes
160 */
161 static ssize_t val_show(struct kobject *kobj,
162 struct kobj_attribute *kobj_attr,
163 char *buf)
164 {
165 struct papr_attr *pattr = container_of(kobj_attr, struct papr_attr,
166 kobj_attr);
167 struct energy_scale_attribute esi;
168 int ret;
169
170 ret = papr_get_attr(pattr->id, &esi);
171 if (ret)
172 return ret;
173
174 return sysfs_emit(buf, "%llu\n", be64_to_cpu(esi.val));
175 }
176
177 /*
178 * Extract and export the value description in string format of the energy
179 * scale attributes
180 */
181 static ssize_t val_desc_show(struct kobject *kobj,
182 struct kobj_attribute *kobj_attr,
183 char *buf)
184 {
185 struct papr_attr *pattr = container_of(kobj_attr, struct papr_attr,
186 kobj_attr);
187 struct energy_scale_attribute esi;
188 int ret;
189
190 ret = papr_get_attr(pattr->id, &esi);
191 if (ret)
192 return ret;
193
194 return sysfs_emit(buf, "%s\n", esi.value_desc);
195 }
196
197 static struct papr_ops_info {
198 const char *attr_name;
199 ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *kobj_attr,
200 char *buf);
201 } ops_info[KOBJ_MAX_ATTRS] = {
202 { "desc", desc_show },
203 { "value", val_show },
204 { "value_desc", val_desc_show },
205 };
206
207 static void add_attr(u64 id, int index, struct papr_attr *attr)
208 {
209 attr->id = id;
210 sysfs_attr_init(&attr->kobj_attr.attr);
211 attr->kobj_attr.attr.name = ops_info[index].attr_name;
212 attr->kobj_attr.attr.mode = 0444;
213 attr->kobj_attr.show = ops_info[index].show;
214 }
215
216 static int add_attr_group(u64 id, struct papr_group *pg, bool show_val_desc)
217 {
218 int i;
219
220 for (i = 0; i < KOBJ_MAX_ATTRS; i++) {
221 if (!strcmp(ops_info[i].attr_name, "value_desc") &&
222 !show_val_desc) {
223 continue;
224 }
225 add_attr(id, i, &pg->pgattrs[i]);
226 pg->pg.attrs[i] = &pg->pgattrs[i].kobj_attr.attr;
227 }
228
229 return sysfs_create_group(esi_kobj, &pg->pg);
230 }
231
232
233 static int __init papr_init(void)
234 {
235 int esi_buf_size = ESI_HDR_SIZE + (CURR_MAX_ESI_ATTRS * ESI_ATTR_SIZE);
236 int ret, idx, i, max_esi_attrs = CURR_MAX_ESI_ATTRS;
237 struct h_energy_scale_info_hdr *esi_hdr;
238 struct energy_scale_attribute *esi_attrs;
239 uint64_t num_attrs;
240 char *esi_buf;
241
242 if (!firmware_has_feature(FW_FEATURE_LPAR) ||
243 !firmware_has_feature(FW_FEATURE_ENERGY_SCALE_INFO)) {
244 return -ENXIO;
245 }
246
247 esi_buf = kmalloc(esi_buf_size, GFP_KERNEL);
248 if (esi_buf == NULL)
249 return -ENOMEM;
250 /*
251 * hcall(
252 * uint64 H_GET_ENERGY_SCALE_INFO, // Get energy scale info
253 * uint64 flags, // Per the flag request
254 * uint64 firstAttributeId, // The attribute id
255 * uint64 bufferAddress, // Guest physical address of the output buffer
256 * uint64 bufferSize); // The size in bytes of the output buffer
257 */
258 retry:
259
260 ret = plpar_hcall_norets(H_GET_ENERGY_SCALE_INFO, ESI_FLAGS_ALL, 0,
261 virt_to_phys(esi_buf), esi_buf_size);
262
263 /*
264 * If the hcall fails with not enough memory for either the
265 * header or data, attempt to allocate more
266 */
267 if (ret == H_PARTIAL || ret == H_P4) {
268 char *temp_esi_buf;
269
270 max_esi_attrs += 4;
271 esi_buf_size = ESI_HDR_SIZE + (CURR_MAX_ESI_ATTRS * max_esi_attrs);
272
273 temp_esi_buf = krealloc(esi_buf, esi_buf_size, GFP_KERNEL);
274 if (temp_esi_buf)
275 esi_buf = temp_esi_buf;
276 else
277 return -ENOMEM;
278
279 goto retry;
280 }
281
282 if (ret != H_SUCCESS) {
283 pr_warn("hcall failed: H_GET_ENERGY_SCALE_INFO, ret: %d\n", ret);
284 goto out_free_esi_buf;
285 }
286
287 esi_hdr = (struct h_energy_scale_info_hdr *) esi_buf;
288 num_attrs = be64_to_cpu(esi_hdr->num_attrs);
289 esi_attrs = (struct energy_scale_attribute *)
290 (esi_buf + be64_to_cpu(esi_hdr->array_offset));
291
292 if (esi_buf_size <
293 be64_to_cpu(esi_hdr->array_offset) +
294 (num_attrs * sizeof(struct energy_scale_attribute))) {
295 goto out_free_esi_buf;
296 }
297
298 papr_groups = kcalloc(num_attrs, sizeof(*papr_groups), GFP_KERNEL);
299 if (!papr_groups)
300 goto out_free_esi_buf;
301
302 papr_kobj = kobject_create_and_add("papr", firmware_kobj);
303 if (!papr_kobj) {
304 pr_warn("kobject_create_and_add papr failed\n");
305 goto out_papr_groups;
306 }
307
308 esi_kobj = kobject_create_and_add("energy_scale_info", papr_kobj);
309 if (!esi_kobj) {
310 pr_warn("kobject_create_and_add energy_scale_info failed\n");
311 goto out_kobj;
312 }
313
314 /* Allocate the groups before registering */
315 for (idx = 0; idx < num_attrs; idx++) {
316 papr_groups[idx].pg.attrs = kcalloc(KOBJ_MAX_ATTRS + 1,
317 sizeof(*papr_groups[idx].pg.attrs),
318 GFP_KERNEL);
319 if (!papr_groups[idx].pg.attrs)
320 goto out_pgattrs;
321
322 papr_groups[idx].pg.name = kasprintf(GFP_KERNEL, "%lld",
323 be64_to_cpu(esi_attrs[idx].id));
324 if (papr_groups[idx].pg.name == NULL)
325 goto out_pgattrs;
326 }
327
328 for (idx = 0; idx < num_attrs; idx++) {
329 bool show_val_desc = true;
330
331 /* Do not add the value desc attr if it does not exist */
332 if (strnlen(esi_attrs[idx].value_desc,
333 sizeof(esi_attrs[idx].value_desc)) == 0)
334 show_val_desc = false;
335
336 if (add_attr_group(be64_to_cpu(esi_attrs[idx].id),
337 &papr_groups[idx],
338 show_val_desc)) {
339 pr_warn("Failed to create papr attribute group %s\n",
340 papr_groups[idx].pg.name);
341 idx = num_attrs;
342 goto out_pgattrs;
343 }
344 }
345
346 kfree(esi_buf);
347 return 0;
348 out_pgattrs:
349 for (i = 0; i < idx ; i++) {
350 kfree(papr_groups[i].pg.attrs);
351 kfree(papr_groups[i].pg.name);
352 }
353 kobject_put(esi_kobj);
354 out_kobj:
355 kobject_put(papr_kobj);
356 out_papr_groups:
357 kfree(papr_groups);
358 out_free_esi_buf:
359 kfree(esi_buf);
360
361 return -ENOMEM;
362 }
363
364 machine_device_initcall(pseries, papr_init);
365
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