1// SPDX-License-Identifier: GPL-2.0
2/*
3 * System Control and Management Interface (SCMI) Voltage Protocol
4 *
5 * Copyright (C) 2020-2022 ARM Ltd.
6 */
7
8#include <linux/module.h>
9#include <linux/scmi_protocol.h>
10
11#include "protocols.h"
12
13/* Updated only after ALL the mandatory features for that version are merged */
14#define SCMI_PROTOCOL_SUPPORTED_VERSION 0x20000
15
16#define VOLTAGE_DOMS_NUM_MASK GENMASK(15, 0)
17#define REMAINING_LEVELS_MASK GENMASK(31, 16)
18#define RETURNED_LEVELS_MASK GENMASK(11, 0)
19
20enum scmi_voltage_protocol_cmd {
21 VOLTAGE_DOMAIN_ATTRIBUTES = 0x3,
22 VOLTAGE_DESCRIBE_LEVELS = 0x4,
23 VOLTAGE_CONFIG_SET = 0x5,
24 VOLTAGE_CONFIG_GET = 0x6,
25 VOLTAGE_LEVEL_SET = 0x7,
26 VOLTAGE_LEVEL_GET = 0x8,
27 VOLTAGE_DOMAIN_NAME_GET = 0x09,
28};
29
30#define NUM_VOLTAGE_DOMAINS(x) ((u16)(FIELD_GET(VOLTAGE_DOMS_NUM_MASK, (x))))
31
32struct scmi_msg_resp_domain_attributes {
33 __le32 attr;
34#define SUPPORTS_ASYNC_LEVEL_SET(x) ((x) & BIT(31))
35#define SUPPORTS_EXTENDED_NAMES(x) ((x) & BIT(30))
36 u8 name[SCMI_SHORT_NAME_MAX_SIZE];
37};
38
39struct scmi_msg_cmd_describe_levels {
40 __le32 domain_id;
41 __le32 level_index;
42};
43
44struct scmi_msg_resp_describe_levels {
45 __le32 flags;
46#define NUM_REMAINING_LEVELS(f) ((u16)(FIELD_GET(REMAINING_LEVELS_MASK, (f))))
47#define NUM_RETURNED_LEVELS(f) ((u16)(FIELD_GET(RETURNED_LEVELS_MASK, (f))))
48#define SUPPORTS_SEGMENTED_LEVELS(f) ((f) & BIT(12))
49 __le32 voltage[];
50};
51
52struct scmi_msg_cmd_config_set {
53 __le32 domain_id;
54 __le32 config;
55};
56
57struct scmi_msg_cmd_level_set {
58 __le32 domain_id;
59 __le32 flags;
60 __le32 voltage_level;
61};
62
63struct scmi_resp_voltage_level_set_complete {
64 __le32 domain_id;
65 __le32 voltage_level;
66};
67
68struct voltage_info {
69 unsigned int version;
70 unsigned int num_domains;
71 struct scmi_voltage_info *domains;
72};
73
74static int scmi_protocol_attributes_get(const struct scmi_protocol_handle *ph,
75 struct voltage_info *vinfo)
76{
77 int ret;
78 struct scmi_xfer *t;
79
80 ret = ph->xops->xfer_get_init(ph, PROTOCOL_ATTRIBUTES, 0,
81 sizeof(__le32), &t);
82 if (ret)
83 return ret;
84
85 ret = ph->xops->do_xfer(ph, t);
86 if (!ret)
87 vinfo->num_domains =
88 NUM_VOLTAGE_DOMAINS(get_unaligned_le32(t->rx.buf));
89
90 ph->xops->xfer_put(ph, t);
91 return ret;
92}
93
94static int scmi_init_voltage_levels(struct device *dev,
95 struct scmi_voltage_info *v,
96 u32 num_returned, u32 num_remaining,
97 bool segmented)
98{
99 u32 num_levels;
100
101 num_levels = num_returned + num_remaining;
102 /*
103 * segmented levels entries are represented by a single triplet
104 * returned all in one go.
105 */
106 if (!num_levels ||
107 (segmented && (num_remaining || num_returned != 3))) {
108 dev_err(dev,
109 "Invalid level descriptor(%d/%d/%d) for voltage dom %d\n",
110 num_levels, num_returned, num_remaining, v->id);
111 return -EINVAL;
112 }
113
114 v->levels_uv = devm_kcalloc(dev, n: num_levels, size: sizeof(u32), GFP_KERNEL);
115 if (!v->levels_uv)
116 return -ENOMEM;
117
118 v->num_levels = num_levels;
119 v->segmented = segmented;
120
121 return 0;
122}
123
124struct scmi_volt_ipriv {
125 struct device *dev;
126 struct scmi_voltage_info *v;
127};
128
129static void iter_volt_levels_prepare_message(void *message,
130 unsigned int desc_index,
131 const void *priv)
132{
133 struct scmi_msg_cmd_describe_levels *msg = message;
134 const struct scmi_volt_ipriv *p = priv;
135
136 msg->domain_id = cpu_to_le32(p->v->id);
137 msg->level_index = cpu_to_le32(desc_index);
138}
139
140static int iter_volt_levels_update_state(struct scmi_iterator_state *st,
141 const void *response, void *priv)
142{
143 int ret = 0;
144 u32 flags;
145 const struct scmi_msg_resp_describe_levels *r = response;
146 struct scmi_volt_ipriv *p = priv;
147
148 flags = le32_to_cpu(r->flags);
149 st->num_returned = NUM_RETURNED_LEVELS(flags);
150 st->num_remaining = NUM_REMAINING_LEVELS(flags);
151
152 /* Allocate space for num_levels if not already done */
153 if (!p->v->num_levels) {
154 ret = scmi_init_voltage_levels(dev: p->dev, v: p->v, num_returned: st->num_returned,
155 num_remaining: st->num_remaining,
156 SUPPORTS_SEGMENTED_LEVELS(flags));
157 if (!ret)
158 st->max_resources = p->v->num_levels;
159 }
160
161 return ret;
162}
163
164static int
165iter_volt_levels_process_response(const struct scmi_protocol_handle *ph,
166 const void *response,
167 struct scmi_iterator_state *st, void *priv)
168{
169 s32 val;
170 const struct scmi_msg_resp_describe_levels *r = response;
171 struct scmi_volt_ipriv *p = priv;
172
173 val = (s32)le32_to_cpu(r->voltage[st->loop_idx]);
174 p->v->levels_uv[st->desc_index + st->loop_idx] = val;
175 if (val < 0)
176 p->v->negative_volts_allowed = true;
177
178 return 0;
179}
180
181static int scmi_voltage_levels_get(const struct scmi_protocol_handle *ph,
182 struct scmi_voltage_info *v)
183{
184 int ret;
185 void *iter;
186 struct scmi_iterator_ops ops = {
187 .prepare_message = iter_volt_levels_prepare_message,
188 .update_state = iter_volt_levels_update_state,
189 .process_response = iter_volt_levels_process_response,
190 };
191 struct scmi_volt_ipriv vpriv = {
192 .dev = ph->dev,
193 .v = v,
194 };
195
196 iter = ph->hops->iter_response_init(ph, &ops, v->num_levels,
197 VOLTAGE_DESCRIBE_LEVELS,
198 sizeof(struct scmi_msg_cmd_describe_levels),
199 &vpriv);
200 if (IS_ERR(ptr: iter))
201 return PTR_ERR(ptr: iter);
202
203 ret = ph->hops->iter_response_run(iter);
204 if (ret) {
205 v->num_levels = 0;
206 devm_kfree(dev: ph->dev, p: v->levels_uv);
207 }
208
209 return ret;
210}
211
212static int scmi_voltage_descriptors_get(const struct scmi_protocol_handle *ph,
213 struct voltage_info *vinfo)
214{
215 int ret, dom;
216 struct scmi_xfer *td;
217 struct scmi_msg_resp_domain_attributes *resp_dom;
218
219 ret = ph->xops->xfer_get_init(ph, VOLTAGE_DOMAIN_ATTRIBUTES,
220 sizeof(__le32), sizeof(*resp_dom), &td);
221 if (ret)
222 return ret;
223 resp_dom = td->rx.buf;
224
225 for (dom = 0; dom < vinfo->num_domains; dom++) {
226 u32 attributes;
227 struct scmi_voltage_info *v;
228
229 /* Retrieve domain attributes at first ... */
230 put_unaligned_le32(val: dom, p: td->tx.buf);
231 /* Skip domain on comms error */
232 if (ph->xops->do_xfer(ph, td))
233 continue;
234
235 v = vinfo->domains + dom;
236 v->id = dom;
237 attributes = le32_to_cpu(resp_dom->attr);
238 strscpy(v->name, resp_dom->name, SCMI_SHORT_NAME_MAX_SIZE);
239
240 /*
241 * If supported overwrite short name with the extended one;
242 * on error just carry on and use already provided short name.
243 */
244 if (PROTOCOL_REV_MAJOR(vinfo->version) >= 0x2) {
245 if (SUPPORTS_EXTENDED_NAMES(attributes))
246 ph->hops->extended_name_get(ph,
247 VOLTAGE_DOMAIN_NAME_GET,
248 v->id, NULL, v->name,
249 SCMI_MAX_STR_SIZE);
250 if (SUPPORTS_ASYNC_LEVEL_SET(attributes))
251 v->async_level_set = true;
252 }
253
254 /* Skip invalid voltage descriptors */
255 scmi_voltage_levels_get(ph, v);
256 }
257
258 ph->xops->xfer_put(ph, td);
259
260 return ret;
261}
262
263static int __scmi_voltage_get_u32(const struct scmi_protocol_handle *ph,
264 u8 cmd_id, u32 domain_id, u32 *value)
265{
266 int ret;
267 struct scmi_xfer *t;
268 struct voltage_info *vinfo = ph->get_priv(ph);
269
270 if (domain_id >= vinfo->num_domains)
271 return -EINVAL;
272
273 ret = ph->xops->xfer_get_init(ph, cmd_id, sizeof(__le32), 0, &t);
274 if (ret)
275 return ret;
276
277 put_unaligned_le32(val: domain_id, p: t->tx.buf);
278 ret = ph->xops->do_xfer(ph, t);
279 if (!ret)
280 *value = get_unaligned_le32(p: t->rx.buf);
281
282 ph->xops->xfer_put(ph, t);
283 return ret;
284}
285
286static int scmi_voltage_config_set(const struct scmi_protocol_handle *ph,
287 u32 domain_id, u32 config)
288{
289 int ret;
290 struct scmi_xfer *t;
291 struct voltage_info *vinfo = ph->get_priv(ph);
292 struct scmi_msg_cmd_config_set *cmd;
293
294 if (domain_id >= vinfo->num_domains)
295 return -EINVAL;
296
297 ret = ph->xops->xfer_get_init(ph, VOLTAGE_CONFIG_SET,
298 sizeof(*cmd), 0, &t);
299 if (ret)
300 return ret;
301
302 cmd = t->tx.buf;
303 cmd->domain_id = cpu_to_le32(domain_id);
304 cmd->config = cpu_to_le32(config & GENMASK(3, 0));
305
306 ret = ph->xops->do_xfer(ph, t);
307
308 ph->xops->xfer_put(ph, t);
309 return ret;
310}
311
312static int scmi_voltage_config_get(const struct scmi_protocol_handle *ph,
313 u32 domain_id, u32 *config)
314{
315 return __scmi_voltage_get_u32(ph, cmd_id: VOLTAGE_CONFIG_GET,
316 domain_id, value: config);
317}
318
319static int scmi_voltage_level_set(const struct scmi_protocol_handle *ph,
320 u32 domain_id,
321 enum scmi_voltage_level_mode mode,
322 s32 volt_uV)
323{
324 int ret;
325 struct scmi_xfer *t;
326 struct voltage_info *vinfo = ph->get_priv(ph);
327 struct scmi_msg_cmd_level_set *cmd;
328 struct scmi_voltage_info *v;
329
330 if (domain_id >= vinfo->num_domains)
331 return -EINVAL;
332
333 ret = ph->xops->xfer_get_init(ph, VOLTAGE_LEVEL_SET,
334 sizeof(*cmd), 0, &t);
335 if (ret)
336 return ret;
337
338 v = vinfo->domains + domain_id;
339
340 cmd = t->tx.buf;
341 cmd->domain_id = cpu_to_le32(domain_id);
342 cmd->voltage_level = cpu_to_le32(volt_uV);
343
344 if (!v->async_level_set || mode != SCMI_VOLTAGE_LEVEL_SET_AUTO) {
345 cmd->flags = cpu_to_le32(0x0);
346 ret = ph->xops->do_xfer(ph, t);
347 } else {
348 cmd->flags = cpu_to_le32(0x1);
349 ret = ph->xops->do_xfer_with_response(ph, t);
350 if (!ret) {
351 struct scmi_resp_voltage_level_set_complete *resp;
352
353 resp = t->rx.buf;
354 if (le32_to_cpu(resp->domain_id) == domain_id)
355 dev_dbg(ph->dev,
356 "Voltage domain %d set async to %d\n",
357 v->id,
358 le32_to_cpu(resp->voltage_level));
359 else
360 ret = -EPROTO;
361 }
362 }
363
364 ph->xops->xfer_put(ph, t);
365 return ret;
366}
367
368static int scmi_voltage_level_get(const struct scmi_protocol_handle *ph,
369 u32 domain_id, s32 *volt_uV)
370{
371 return __scmi_voltage_get_u32(ph, cmd_id: VOLTAGE_LEVEL_GET,
372 domain_id, value: (u32 *)volt_uV);
373}
374
375static const struct scmi_voltage_info * __must_check
376scmi_voltage_info_get(const struct scmi_protocol_handle *ph, u32 domain_id)
377{
378 struct voltage_info *vinfo = ph->get_priv(ph);
379
380 if (domain_id >= vinfo->num_domains ||
381 !vinfo->domains[domain_id].num_levels)
382 return NULL;
383
384 return vinfo->domains + domain_id;
385}
386
387static int scmi_voltage_domains_num_get(const struct scmi_protocol_handle *ph)
388{
389 struct voltage_info *vinfo = ph->get_priv(ph);
390
391 return vinfo->num_domains;
392}
393
394static struct scmi_voltage_proto_ops voltage_proto_ops = {
395 .num_domains_get = scmi_voltage_domains_num_get,
396 .info_get = scmi_voltage_info_get,
397 .config_set = scmi_voltage_config_set,
398 .config_get = scmi_voltage_config_get,
399 .level_set = scmi_voltage_level_set,
400 .level_get = scmi_voltage_level_get,
401};
402
403static int scmi_voltage_protocol_init(const struct scmi_protocol_handle *ph)
404{
405 int ret;
406 u32 version;
407 struct voltage_info *vinfo;
408
409 ret = ph->xops->version_get(ph, &version);
410 if (ret)
411 return ret;
412
413 dev_dbg(ph->dev, "Voltage Version %d.%d\n",
414 PROTOCOL_REV_MAJOR(version), PROTOCOL_REV_MINOR(version));
415
416 vinfo = devm_kzalloc(dev: ph->dev, size: sizeof(*vinfo), GFP_KERNEL);
417 if (!vinfo)
418 return -ENOMEM;
419 vinfo->version = version;
420
421 ret = scmi_protocol_attributes_get(ph, vinfo);
422 if (ret)
423 return ret;
424
425 if (vinfo->num_domains) {
426 vinfo->domains = devm_kcalloc(dev: ph->dev, n: vinfo->num_domains,
427 size: sizeof(*vinfo->domains),
428 GFP_KERNEL);
429 if (!vinfo->domains)
430 return -ENOMEM;
431 ret = scmi_voltage_descriptors_get(ph, vinfo);
432 if (ret)
433 return ret;
434 } else {
435 dev_warn(ph->dev, "No Voltage domains found.\n");
436 }
437
438 return ph->set_priv(ph, vinfo, version);
439}
440
441static const struct scmi_protocol scmi_voltage = {
442 .id = SCMI_PROTOCOL_VOLTAGE,
443 .owner = THIS_MODULE,
444 .instance_init = &scmi_voltage_protocol_init,
445 .ops = &voltage_proto_ops,
446 .supported_version = SCMI_PROTOCOL_SUPPORTED_VERSION,
447};
448
449DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(voltage, scmi_voltage)
450

source code of linux/drivers/firmware/arm_scmi/voltage.c