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, num_levels, 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(p->dev, p->v, st->num_returned,
155					       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(iter))
201		return PTR_ERR(iter);
202
203	ret = ph->hops->iter_response_run(iter);
204	if (ret) {
205		v->num_levels = 0;
206		devm_kfree(ph->dev, 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(dom, 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(domain_id, t->tx.buf);
278	ret = ph->xops->do_xfer(ph, t);
279	if (!ret)
280		*value = get_unaligned_le32(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, VOLTAGE_CONFIG_GET,
316				      domain_id, 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, VOLTAGE_LEVEL_GET,
372				      domain_id, (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(ph->dev, 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(ph->dev, vinfo->num_domains,
427					      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