xref: /openbmc/linux/drivers/firmware/arm_scpi.c (revision 4f6cce39)
1 /*
2  * System Control and Power Interface (SCPI) Message Protocol driver
3  *
4  * SCPI Message Protocol is used between the System Control Processor(SCP)
5  * and the Application Processors(AP). The Message Handling Unit(MHU)
6  * provides a mechanism for inter-processor communication between SCP's
7  * Cortex M3 and AP.
8  *
9  * SCP offers control and management of the core/cluster power states,
10  * various power domain DVFS including the core/cluster, certain system
11  * clocks configuration, thermal sensors and many others.
12  *
13  * Copyright (C) 2015 ARM Ltd.
14  *
15  * This program is free software; you can redistribute it and/or modify it
16  * under the terms and conditions of the GNU General Public License,
17  * version 2, as published by the Free Software Foundation.
18  *
19  * This program is distributed in the hope it will be useful, but WITHOUT
20  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
21  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
22  * more details.
23  *
24  * You should have received a copy of the GNU General Public License along
25  * with this program. If not, see <http://www.gnu.org/licenses/>.
26  */
27 
28 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
29 
30 #include <linux/bitmap.h>
31 #include <linux/device.h>
32 #include <linux/err.h>
33 #include <linux/export.h>
34 #include <linux/io.h>
35 #include <linux/kernel.h>
36 #include <linux/list.h>
37 #include <linux/mailbox_client.h>
38 #include <linux/module.h>
39 #include <linux/of_address.h>
40 #include <linux/of_platform.h>
41 #include <linux/printk.h>
42 #include <linux/scpi_protocol.h>
43 #include <linux/slab.h>
44 #include <linux/sort.h>
45 #include <linux/spinlock.h>
46 
47 #define CMD_ID_SHIFT		0
48 #define CMD_ID_MASK		0x7f
49 #define CMD_TOKEN_ID_SHIFT	8
50 #define CMD_TOKEN_ID_MASK	0xff
51 #define CMD_DATA_SIZE_SHIFT	16
52 #define CMD_DATA_SIZE_MASK	0x1ff
53 #define CMD_LEGACY_DATA_SIZE_SHIFT	20
54 #define CMD_LEGACY_DATA_SIZE_MASK	0x1ff
55 #define PACK_SCPI_CMD(cmd_id, tx_sz)			\
56 	((((cmd_id) & CMD_ID_MASK) << CMD_ID_SHIFT) |	\
57 	(((tx_sz) & CMD_DATA_SIZE_MASK) << CMD_DATA_SIZE_SHIFT))
58 #define ADD_SCPI_TOKEN(cmd, token)			\
59 	((cmd) |= (((token) & CMD_TOKEN_ID_MASK) << CMD_TOKEN_ID_SHIFT))
60 #define PACK_LEGACY_SCPI_CMD(cmd_id, tx_sz)				\
61 	((((cmd_id) & CMD_ID_MASK) << CMD_ID_SHIFT) |			       \
62 	(((tx_sz) & CMD_LEGACY_DATA_SIZE_MASK) << CMD_LEGACY_DATA_SIZE_SHIFT))
63 
64 #define CMD_SIZE(cmd)	(((cmd) >> CMD_DATA_SIZE_SHIFT) & CMD_DATA_SIZE_MASK)
65 #define CMD_LEGACY_SIZE(cmd)	(((cmd) >> CMD_LEGACY_DATA_SIZE_SHIFT) & \
66 					CMD_LEGACY_DATA_SIZE_MASK)
67 #define CMD_UNIQ_MASK	(CMD_TOKEN_ID_MASK << CMD_TOKEN_ID_SHIFT | CMD_ID_MASK)
68 #define CMD_XTRACT_UNIQ(cmd)	((cmd) & CMD_UNIQ_MASK)
69 
70 #define SCPI_SLOT		0
71 
72 #define MAX_DVFS_DOMAINS	8
73 #define MAX_DVFS_OPPS		16
74 #define DVFS_LATENCY(hdr)	(le32_to_cpu(hdr) >> 16)
75 #define DVFS_OPP_COUNT(hdr)	((le32_to_cpu(hdr) >> 8) & 0xff)
76 
77 #define PROTOCOL_REV_MINOR_BITS	16
78 #define PROTOCOL_REV_MINOR_MASK	((1U << PROTOCOL_REV_MINOR_BITS) - 1)
79 #define PROTOCOL_REV_MAJOR(x)	((x) >> PROTOCOL_REV_MINOR_BITS)
80 #define PROTOCOL_REV_MINOR(x)	((x) & PROTOCOL_REV_MINOR_MASK)
81 
82 #define FW_REV_MAJOR_BITS	24
83 #define FW_REV_MINOR_BITS	16
84 #define FW_REV_PATCH_MASK	((1U << FW_REV_MINOR_BITS) - 1)
85 #define FW_REV_MINOR_MASK	((1U << FW_REV_MAJOR_BITS) - 1)
86 #define FW_REV_MAJOR(x)		((x) >> FW_REV_MAJOR_BITS)
87 #define FW_REV_MINOR(x)		(((x) & FW_REV_MINOR_MASK) >> FW_REV_MINOR_BITS)
88 #define FW_REV_PATCH(x)		((x) & FW_REV_PATCH_MASK)
89 
90 #define MAX_RX_TIMEOUT		(msecs_to_jiffies(30))
91 
92 enum scpi_error_codes {
93 	SCPI_SUCCESS = 0, /* Success */
94 	SCPI_ERR_PARAM = 1, /* Invalid parameter(s) */
95 	SCPI_ERR_ALIGN = 2, /* Invalid alignment */
96 	SCPI_ERR_SIZE = 3, /* Invalid size */
97 	SCPI_ERR_HANDLER = 4, /* Invalid handler/callback */
98 	SCPI_ERR_ACCESS = 5, /* Invalid access/permission denied */
99 	SCPI_ERR_RANGE = 6, /* Value out of range */
100 	SCPI_ERR_TIMEOUT = 7, /* Timeout has occurred */
101 	SCPI_ERR_NOMEM = 8, /* Invalid memory area or pointer */
102 	SCPI_ERR_PWRSTATE = 9, /* Invalid power state */
103 	SCPI_ERR_SUPPORT = 10, /* Not supported or disabled */
104 	SCPI_ERR_DEVICE = 11, /* Device error */
105 	SCPI_ERR_BUSY = 12, /* Device busy */
106 	SCPI_ERR_MAX
107 };
108 
109 /* SCPI Standard commands */
110 enum scpi_std_cmd {
111 	SCPI_CMD_INVALID		= 0x00,
112 	SCPI_CMD_SCPI_READY		= 0x01,
113 	SCPI_CMD_SCPI_CAPABILITIES	= 0x02,
114 	SCPI_CMD_SET_CSS_PWR_STATE	= 0x03,
115 	SCPI_CMD_GET_CSS_PWR_STATE	= 0x04,
116 	SCPI_CMD_SET_SYS_PWR_STATE	= 0x05,
117 	SCPI_CMD_SET_CPU_TIMER		= 0x06,
118 	SCPI_CMD_CANCEL_CPU_TIMER	= 0x07,
119 	SCPI_CMD_DVFS_CAPABILITIES	= 0x08,
120 	SCPI_CMD_GET_DVFS_INFO		= 0x09,
121 	SCPI_CMD_SET_DVFS		= 0x0a,
122 	SCPI_CMD_GET_DVFS		= 0x0b,
123 	SCPI_CMD_GET_DVFS_STAT		= 0x0c,
124 	SCPI_CMD_CLOCK_CAPABILITIES	= 0x0d,
125 	SCPI_CMD_GET_CLOCK_INFO		= 0x0e,
126 	SCPI_CMD_SET_CLOCK_VALUE	= 0x0f,
127 	SCPI_CMD_GET_CLOCK_VALUE	= 0x10,
128 	SCPI_CMD_PSU_CAPABILITIES	= 0x11,
129 	SCPI_CMD_GET_PSU_INFO		= 0x12,
130 	SCPI_CMD_SET_PSU		= 0x13,
131 	SCPI_CMD_GET_PSU		= 0x14,
132 	SCPI_CMD_SENSOR_CAPABILITIES	= 0x15,
133 	SCPI_CMD_SENSOR_INFO		= 0x16,
134 	SCPI_CMD_SENSOR_VALUE		= 0x17,
135 	SCPI_CMD_SENSOR_CFG_PERIODIC	= 0x18,
136 	SCPI_CMD_SENSOR_CFG_BOUNDS	= 0x19,
137 	SCPI_CMD_SENSOR_ASYNC_VALUE	= 0x1a,
138 	SCPI_CMD_SET_DEVICE_PWR_STATE	= 0x1b,
139 	SCPI_CMD_GET_DEVICE_PWR_STATE	= 0x1c,
140 	SCPI_CMD_COUNT
141 };
142 
143 /* SCPI Legacy Commands */
144 enum legacy_scpi_std_cmd {
145 	LEGACY_SCPI_CMD_INVALID			= 0x00,
146 	LEGACY_SCPI_CMD_SCPI_READY		= 0x01,
147 	LEGACY_SCPI_CMD_SCPI_CAPABILITIES	= 0x02,
148 	LEGACY_SCPI_CMD_EVENT			= 0x03,
149 	LEGACY_SCPI_CMD_SET_CSS_PWR_STATE	= 0x04,
150 	LEGACY_SCPI_CMD_GET_CSS_PWR_STATE	= 0x05,
151 	LEGACY_SCPI_CMD_CFG_PWR_STATE_STAT	= 0x06,
152 	LEGACY_SCPI_CMD_GET_PWR_STATE_STAT	= 0x07,
153 	LEGACY_SCPI_CMD_SYS_PWR_STATE		= 0x08,
154 	LEGACY_SCPI_CMD_L2_READY		= 0x09,
155 	LEGACY_SCPI_CMD_SET_AP_TIMER		= 0x0a,
156 	LEGACY_SCPI_CMD_CANCEL_AP_TIME		= 0x0b,
157 	LEGACY_SCPI_CMD_DVFS_CAPABILITIES	= 0x0c,
158 	LEGACY_SCPI_CMD_GET_DVFS_INFO		= 0x0d,
159 	LEGACY_SCPI_CMD_SET_DVFS		= 0x0e,
160 	LEGACY_SCPI_CMD_GET_DVFS		= 0x0f,
161 	LEGACY_SCPI_CMD_GET_DVFS_STAT		= 0x10,
162 	LEGACY_SCPI_CMD_SET_RTC			= 0x11,
163 	LEGACY_SCPI_CMD_GET_RTC			= 0x12,
164 	LEGACY_SCPI_CMD_CLOCK_CAPABILITIES	= 0x13,
165 	LEGACY_SCPI_CMD_SET_CLOCK_INDEX		= 0x14,
166 	LEGACY_SCPI_CMD_SET_CLOCK_VALUE		= 0x15,
167 	LEGACY_SCPI_CMD_GET_CLOCK_VALUE		= 0x16,
168 	LEGACY_SCPI_CMD_PSU_CAPABILITIES	= 0x17,
169 	LEGACY_SCPI_CMD_SET_PSU			= 0x18,
170 	LEGACY_SCPI_CMD_GET_PSU			= 0x19,
171 	LEGACY_SCPI_CMD_SENSOR_CAPABILITIES	= 0x1a,
172 	LEGACY_SCPI_CMD_SENSOR_INFO		= 0x1b,
173 	LEGACY_SCPI_CMD_SENSOR_VALUE		= 0x1c,
174 	LEGACY_SCPI_CMD_SENSOR_CFG_PERIODIC	= 0x1d,
175 	LEGACY_SCPI_CMD_SENSOR_CFG_BOUNDS	= 0x1e,
176 	LEGACY_SCPI_CMD_SENSOR_ASYNC_VALUE	= 0x1f,
177 	LEGACY_SCPI_CMD_COUNT
178 };
179 
180 /* List all commands that are required to go through the high priority link */
181 static int legacy_hpriority_cmds[] = {
182 	LEGACY_SCPI_CMD_GET_CSS_PWR_STATE,
183 	LEGACY_SCPI_CMD_CFG_PWR_STATE_STAT,
184 	LEGACY_SCPI_CMD_GET_PWR_STATE_STAT,
185 	LEGACY_SCPI_CMD_SET_DVFS,
186 	LEGACY_SCPI_CMD_GET_DVFS,
187 	LEGACY_SCPI_CMD_SET_RTC,
188 	LEGACY_SCPI_CMD_GET_RTC,
189 	LEGACY_SCPI_CMD_SET_CLOCK_INDEX,
190 	LEGACY_SCPI_CMD_SET_CLOCK_VALUE,
191 	LEGACY_SCPI_CMD_GET_CLOCK_VALUE,
192 	LEGACY_SCPI_CMD_SET_PSU,
193 	LEGACY_SCPI_CMD_GET_PSU,
194 	LEGACY_SCPI_CMD_SENSOR_CFG_PERIODIC,
195 	LEGACY_SCPI_CMD_SENSOR_CFG_BOUNDS,
196 };
197 
198 /* List all commands used by this driver, used as indexes */
199 enum scpi_drv_cmds {
200 	CMD_SCPI_CAPABILITIES = 0,
201 	CMD_GET_CLOCK_INFO,
202 	CMD_GET_CLOCK_VALUE,
203 	CMD_SET_CLOCK_VALUE,
204 	CMD_GET_DVFS,
205 	CMD_SET_DVFS,
206 	CMD_GET_DVFS_INFO,
207 	CMD_SENSOR_CAPABILITIES,
208 	CMD_SENSOR_INFO,
209 	CMD_SENSOR_VALUE,
210 	CMD_SET_DEVICE_PWR_STATE,
211 	CMD_GET_DEVICE_PWR_STATE,
212 	CMD_MAX_COUNT,
213 };
214 
215 static int scpi_std_commands[CMD_MAX_COUNT] = {
216 	SCPI_CMD_SCPI_CAPABILITIES,
217 	SCPI_CMD_GET_CLOCK_INFO,
218 	SCPI_CMD_GET_CLOCK_VALUE,
219 	SCPI_CMD_SET_CLOCK_VALUE,
220 	SCPI_CMD_GET_DVFS,
221 	SCPI_CMD_SET_DVFS,
222 	SCPI_CMD_GET_DVFS_INFO,
223 	SCPI_CMD_SENSOR_CAPABILITIES,
224 	SCPI_CMD_SENSOR_INFO,
225 	SCPI_CMD_SENSOR_VALUE,
226 	SCPI_CMD_SET_DEVICE_PWR_STATE,
227 	SCPI_CMD_GET_DEVICE_PWR_STATE,
228 };
229 
230 static int scpi_legacy_commands[CMD_MAX_COUNT] = {
231 	LEGACY_SCPI_CMD_SCPI_CAPABILITIES,
232 	-1, /* GET_CLOCK_INFO */
233 	LEGACY_SCPI_CMD_GET_CLOCK_VALUE,
234 	LEGACY_SCPI_CMD_SET_CLOCK_VALUE,
235 	LEGACY_SCPI_CMD_GET_DVFS,
236 	LEGACY_SCPI_CMD_SET_DVFS,
237 	LEGACY_SCPI_CMD_GET_DVFS_INFO,
238 	LEGACY_SCPI_CMD_SENSOR_CAPABILITIES,
239 	LEGACY_SCPI_CMD_SENSOR_INFO,
240 	LEGACY_SCPI_CMD_SENSOR_VALUE,
241 	-1, /* SET_DEVICE_PWR_STATE */
242 	-1, /* GET_DEVICE_PWR_STATE */
243 };
244 
245 struct scpi_xfer {
246 	u32 slot; /* has to be first element */
247 	u32 cmd;
248 	u32 status;
249 	const void *tx_buf;
250 	void *rx_buf;
251 	unsigned int tx_len;
252 	unsigned int rx_len;
253 	struct list_head node;
254 	struct completion done;
255 };
256 
257 struct scpi_chan {
258 	struct mbox_client cl;
259 	struct mbox_chan *chan;
260 	void __iomem *tx_payload;
261 	void __iomem *rx_payload;
262 	struct list_head rx_pending;
263 	struct list_head xfers_list;
264 	struct scpi_xfer *xfers;
265 	spinlock_t rx_lock; /* locking for the rx pending list */
266 	struct mutex xfers_lock;
267 	u8 token;
268 };
269 
270 struct scpi_drvinfo {
271 	u32 protocol_version;
272 	u32 firmware_version;
273 	bool is_legacy;
274 	int num_chans;
275 	int *commands;
276 	DECLARE_BITMAP(cmd_priority, LEGACY_SCPI_CMD_COUNT);
277 	atomic_t next_chan;
278 	struct scpi_ops *scpi_ops;
279 	struct scpi_chan *channels;
280 	struct scpi_dvfs_info *dvfs[MAX_DVFS_DOMAINS];
281 };
282 
283 /*
284  * The SCP firmware only executes in little-endian mode, so any buffers
285  * shared through SCPI should have their contents converted to little-endian
286  */
287 struct scpi_shared_mem {
288 	__le32 command;
289 	__le32 status;
290 	u8 payload[0];
291 } __packed;
292 
293 struct legacy_scpi_shared_mem {
294 	__le32 status;
295 	u8 payload[0];
296 } __packed;
297 
298 struct scp_capabilities {
299 	__le32 protocol_version;
300 	__le32 event_version;
301 	__le32 platform_version;
302 	__le32 commands[4];
303 } __packed;
304 
305 struct clk_get_info {
306 	__le16 id;
307 	__le16 flags;
308 	__le32 min_rate;
309 	__le32 max_rate;
310 	u8 name[20];
311 } __packed;
312 
313 struct clk_get_value {
314 	__le32 rate;
315 } __packed;
316 
317 struct clk_set_value {
318 	__le16 id;
319 	__le16 reserved;
320 	__le32 rate;
321 } __packed;
322 
323 struct legacy_clk_set_value {
324 	__le32 rate;
325 	__le16 id;
326 	__le16 reserved;
327 } __packed;
328 
329 struct dvfs_info {
330 	__le32 header;
331 	struct {
332 		__le32 freq;
333 		__le32 m_volt;
334 	} opps[MAX_DVFS_OPPS];
335 } __packed;
336 
337 struct dvfs_set {
338 	u8 domain;
339 	u8 index;
340 } __packed;
341 
342 struct sensor_capabilities {
343 	__le16 sensors;
344 } __packed;
345 
346 struct _scpi_sensor_info {
347 	__le16 sensor_id;
348 	u8 class;
349 	u8 trigger_type;
350 	char name[20];
351 };
352 
353 struct sensor_value {
354 	__le32 lo_val;
355 	__le32 hi_val;
356 } __packed;
357 
358 struct dev_pstate_set {
359 	u16 dev_id;
360 	u8 pstate;
361 } __packed;
362 
363 static struct scpi_drvinfo *scpi_info;
364 
365 static int scpi_linux_errmap[SCPI_ERR_MAX] = {
366 	/* better than switch case as long as return value is continuous */
367 	0, /* SCPI_SUCCESS */
368 	-EINVAL, /* SCPI_ERR_PARAM */
369 	-ENOEXEC, /* SCPI_ERR_ALIGN */
370 	-EMSGSIZE, /* SCPI_ERR_SIZE */
371 	-EINVAL, /* SCPI_ERR_HANDLER */
372 	-EACCES, /* SCPI_ERR_ACCESS */
373 	-ERANGE, /* SCPI_ERR_RANGE */
374 	-ETIMEDOUT, /* SCPI_ERR_TIMEOUT */
375 	-ENOMEM, /* SCPI_ERR_NOMEM */
376 	-EINVAL, /* SCPI_ERR_PWRSTATE */
377 	-EOPNOTSUPP, /* SCPI_ERR_SUPPORT */
378 	-EIO, /* SCPI_ERR_DEVICE */
379 	-EBUSY, /* SCPI_ERR_BUSY */
380 };
381 
382 static inline int scpi_to_linux_errno(int errno)
383 {
384 	if (errno >= SCPI_SUCCESS && errno < SCPI_ERR_MAX)
385 		return scpi_linux_errmap[errno];
386 	return -EIO;
387 }
388 
389 static void scpi_process_cmd(struct scpi_chan *ch, u32 cmd)
390 {
391 	unsigned long flags;
392 	struct scpi_xfer *t, *match = NULL;
393 
394 	spin_lock_irqsave(&ch->rx_lock, flags);
395 	if (list_empty(&ch->rx_pending)) {
396 		spin_unlock_irqrestore(&ch->rx_lock, flags);
397 		return;
398 	}
399 
400 	/* Command type is not replied by the SCP Firmware in legacy Mode
401 	 * We should consider that command is the head of pending RX commands
402 	 * if the list is not empty. In TX only mode, the list would be empty.
403 	 */
404 	if (scpi_info->is_legacy) {
405 		match = list_first_entry(&ch->rx_pending, struct scpi_xfer,
406 					 node);
407 		list_del(&match->node);
408 	} else {
409 		list_for_each_entry(t, &ch->rx_pending, node)
410 			if (CMD_XTRACT_UNIQ(t->cmd) == CMD_XTRACT_UNIQ(cmd)) {
411 				list_del(&t->node);
412 				match = t;
413 				break;
414 			}
415 	}
416 	/* check if wait_for_completion is in progress or timed-out */
417 	if (match && !completion_done(&match->done)) {
418 		unsigned int len;
419 
420 		if (scpi_info->is_legacy) {
421 			struct legacy_scpi_shared_mem *mem = ch->rx_payload;
422 
423 			/* RX Length is not replied by the legacy Firmware */
424 			len = match->rx_len;
425 
426 			match->status = le32_to_cpu(mem->status);
427 			memcpy_fromio(match->rx_buf, mem->payload, len);
428 		} else {
429 			struct scpi_shared_mem *mem = ch->rx_payload;
430 
431 			len = min(match->rx_len, CMD_SIZE(cmd));
432 
433 			match->status = le32_to_cpu(mem->status);
434 			memcpy_fromio(match->rx_buf, mem->payload, len);
435 		}
436 
437 		if (match->rx_len > len)
438 			memset(match->rx_buf + len, 0, match->rx_len - len);
439 		complete(&match->done);
440 	}
441 	spin_unlock_irqrestore(&ch->rx_lock, flags);
442 }
443 
444 static void scpi_handle_remote_msg(struct mbox_client *c, void *msg)
445 {
446 	struct scpi_chan *ch = container_of(c, struct scpi_chan, cl);
447 	struct scpi_shared_mem *mem = ch->rx_payload;
448 	u32 cmd = 0;
449 
450 	if (!scpi_info->is_legacy)
451 		cmd = le32_to_cpu(mem->command);
452 
453 	scpi_process_cmd(ch, cmd);
454 }
455 
456 static void scpi_tx_prepare(struct mbox_client *c, void *msg)
457 {
458 	unsigned long flags;
459 	struct scpi_xfer *t = msg;
460 	struct scpi_chan *ch = container_of(c, struct scpi_chan, cl);
461 	struct scpi_shared_mem *mem = (struct scpi_shared_mem *)ch->tx_payload;
462 
463 	if (t->tx_buf) {
464 		if (scpi_info->is_legacy)
465 			memcpy_toio(ch->tx_payload, t->tx_buf, t->tx_len);
466 		else
467 			memcpy_toio(mem->payload, t->tx_buf, t->tx_len);
468 	}
469 
470 	if (t->rx_buf) {
471 		if (!(++ch->token))
472 			++ch->token;
473 		ADD_SCPI_TOKEN(t->cmd, ch->token);
474 		spin_lock_irqsave(&ch->rx_lock, flags);
475 		list_add_tail(&t->node, &ch->rx_pending);
476 		spin_unlock_irqrestore(&ch->rx_lock, flags);
477 	}
478 
479 	if (!scpi_info->is_legacy)
480 		mem->command = cpu_to_le32(t->cmd);
481 }
482 
483 static struct scpi_xfer *get_scpi_xfer(struct scpi_chan *ch)
484 {
485 	struct scpi_xfer *t;
486 
487 	mutex_lock(&ch->xfers_lock);
488 	if (list_empty(&ch->xfers_list)) {
489 		mutex_unlock(&ch->xfers_lock);
490 		return NULL;
491 	}
492 	t = list_first_entry(&ch->xfers_list, struct scpi_xfer, node);
493 	list_del(&t->node);
494 	mutex_unlock(&ch->xfers_lock);
495 	return t;
496 }
497 
498 static void put_scpi_xfer(struct scpi_xfer *t, struct scpi_chan *ch)
499 {
500 	mutex_lock(&ch->xfers_lock);
501 	list_add_tail(&t->node, &ch->xfers_list);
502 	mutex_unlock(&ch->xfers_lock);
503 }
504 
505 static int scpi_send_message(u8 idx, void *tx_buf, unsigned int tx_len,
506 			     void *rx_buf, unsigned int rx_len)
507 {
508 	int ret;
509 	u8 chan;
510 	u8 cmd;
511 	struct scpi_xfer *msg;
512 	struct scpi_chan *scpi_chan;
513 
514 	if (scpi_info->commands[idx] < 0)
515 		return -EOPNOTSUPP;
516 
517 	cmd = scpi_info->commands[idx];
518 
519 	if (scpi_info->is_legacy)
520 		chan = test_bit(cmd, scpi_info->cmd_priority) ? 1 : 0;
521 	else
522 		chan = atomic_inc_return(&scpi_info->next_chan) %
523 			scpi_info->num_chans;
524 	scpi_chan = scpi_info->channels + chan;
525 
526 	msg = get_scpi_xfer(scpi_chan);
527 	if (!msg)
528 		return -ENOMEM;
529 
530 	if (scpi_info->is_legacy) {
531 		msg->cmd = PACK_LEGACY_SCPI_CMD(cmd, tx_len);
532 		msg->slot = msg->cmd;
533 	} else {
534 		msg->slot = BIT(SCPI_SLOT);
535 		msg->cmd = PACK_SCPI_CMD(cmd, tx_len);
536 	}
537 	msg->tx_buf = tx_buf;
538 	msg->tx_len = tx_len;
539 	msg->rx_buf = rx_buf;
540 	msg->rx_len = rx_len;
541 	init_completion(&msg->done);
542 
543 	ret = mbox_send_message(scpi_chan->chan, msg);
544 	if (ret < 0 || !rx_buf)
545 		goto out;
546 
547 	if (!wait_for_completion_timeout(&msg->done, MAX_RX_TIMEOUT))
548 		ret = -ETIMEDOUT;
549 	else
550 		/* first status word */
551 		ret = msg->status;
552 out:
553 	if (ret < 0 && rx_buf) /* remove entry from the list if timed-out */
554 		scpi_process_cmd(scpi_chan, msg->cmd);
555 
556 	put_scpi_xfer(msg, scpi_chan);
557 	/* SCPI error codes > 0, translate them to Linux scale*/
558 	return ret > 0 ? scpi_to_linux_errno(ret) : ret;
559 }
560 
561 static u32 scpi_get_version(void)
562 {
563 	return scpi_info->protocol_version;
564 }
565 
566 static int
567 scpi_clk_get_range(u16 clk_id, unsigned long *min, unsigned long *max)
568 {
569 	int ret;
570 	struct clk_get_info clk;
571 	__le16 le_clk_id = cpu_to_le16(clk_id);
572 
573 	ret = scpi_send_message(CMD_GET_CLOCK_INFO, &le_clk_id,
574 				sizeof(le_clk_id), &clk, sizeof(clk));
575 	if (!ret) {
576 		*min = le32_to_cpu(clk.min_rate);
577 		*max = le32_to_cpu(clk.max_rate);
578 	}
579 	return ret;
580 }
581 
582 static unsigned long scpi_clk_get_val(u16 clk_id)
583 {
584 	int ret;
585 	struct clk_get_value clk;
586 	__le16 le_clk_id = cpu_to_le16(clk_id);
587 
588 	ret = scpi_send_message(CMD_GET_CLOCK_VALUE, &le_clk_id,
589 				sizeof(le_clk_id), &clk, sizeof(clk));
590 
591 	return ret ? ret : le32_to_cpu(clk.rate);
592 }
593 
594 static int scpi_clk_set_val(u16 clk_id, unsigned long rate)
595 {
596 	int stat;
597 	struct clk_set_value clk = {
598 		.id = cpu_to_le16(clk_id),
599 		.rate = cpu_to_le32(rate)
600 	};
601 
602 	return scpi_send_message(CMD_SET_CLOCK_VALUE, &clk, sizeof(clk),
603 				 &stat, sizeof(stat));
604 }
605 
606 static int legacy_scpi_clk_set_val(u16 clk_id, unsigned long rate)
607 {
608 	int stat;
609 	struct legacy_clk_set_value clk = {
610 		.id = cpu_to_le16(clk_id),
611 		.rate = cpu_to_le32(rate)
612 	};
613 
614 	return scpi_send_message(CMD_SET_CLOCK_VALUE, &clk, sizeof(clk),
615 				 &stat, sizeof(stat));
616 }
617 
618 static int scpi_dvfs_get_idx(u8 domain)
619 {
620 	int ret;
621 	u8 dvfs_idx;
622 
623 	ret = scpi_send_message(CMD_GET_DVFS, &domain, sizeof(domain),
624 				&dvfs_idx, sizeof(dvfs_idx));
625 
626 	return ret ? ret : dvfs_idx;
627 }
628 
629 static int scpi_dvfs_set_idx(u8 domain, u8 index)
630 {
631 	int stat;
632 	struct dvfs_set dvfs = {domain, index};
633 
634 	return scpi_send_message(CMD_SET_DVFS, &dvfs, sizeof(dvfs),
635 				 &stat, sizeof(stat));
636 }
637 
638 static int opp_cmp_func(const void *opp1, const void *opp2)
639 {
640 	const struct scpi_opp *t1 = opp1, *t2 = opp2;
641 
642 	return t1->freq - t2->freq;
643 }
644 
645 static struct scpi_dvfs_info *scpi_dvfs_get_info(u8 domain)
646 {
647 	struct scpi_dvfs_info *info;
648 	struct scpi_opp *opp;
649 	struct dvfs_info buf;
650 	int ret, i;
651 
652 	if (domain >= MAX_DVFS_DOMAINS)
653 		return ERR_PTR(-EINVAL);
654 
655 	if (scpi_info->dvfs[domain])	/* data already populated */
656 		return scpi_info->dvfs[domain];
657 
658 	ret = scpi_send_message(CMD_GET_DVFS_INFO, &domain, sizeof(domain),
659 				&buf, sizeof(buf));
660 	if (ret)
661 		return ERR_PTR(ret);
662 
663 	info = kmalloc(sizeof(*info), GFP_KERNEL);
664 	if (!info)
665 		return ERR_PTR(-ENOMEM);
666 
667 	info->count = DVFS_OPP_COUNT(buf.header);
668 	info->latency = DVFS_LATENCY(buf.header) * 1000; /* uS to nS */
669 
670 	info->opps = kcalloc(info->count, sizeof(*opp), GFP_KERNEL);
671 	if (!info->opps) {
672 		kfree(info);
673 		return ERR_PTR(-ENOMEM);
674 	}
675 
676 	for (i = 0, opp = info->opps; i < info->count; i++, opp++) {
677 		opp->freq = le32_to_cpu(buf.opps[i].freq);
678 		opp->m_volt = le32_to_cpu(buf.opps[i].m_volt);
679 	}
680 
681 	sort(info->opps, info->count, sizeof(*opp), opp_cmp_func, NULL);
682 
683 	scpi_info->dvfs[domain] = info;
684 	return info;
685 }
686 
687 static int scpi_sensor_get_capability(u16 *sensors)
688 {
689 	struct sensor_capabilities cap_buf;
690 	int ret;
691 
692 	ret = scpi_send_message(CMD_SENSOR_CAPABILITIES, NULL, 0, &cap_buf,
693 				sizeof(cap_buf));
694 	if (!ret)
695 		*sensors = le16_to_cpu(cap_buf.sensors);
696 
697 	return ret;
698 }
699 
700 static int scpi_sensor_get_info(u16 sensor_id, struct scpi_sensor_info *info)
701 {
702 	__le16 id = cpu_to_le16(sensor_id);
703 	struct _scpi_sensor_info _info;
704 	int ret;
705 
706 	ret = scpi_send_message(CMD_SENSOR_INFO, &id, sizeof(id),
707 				&_info, sizeof(_info));
708 	if (!ret) {
709 		memcpy(info, &_info, sizeof(*info));
710 		info->sensor_id = le16_to_cpu(_info.sensor_id);
711 	}
712 
713 	return ret;
714 }
715 
716 static int scpi_sensor_get_value(u16 sensor, u64 *val)
717 {
718 	__le16 id = cpu_to_le16(sensor);
719 	struct sensor_value buf;
720 	int ret;
721 
722 	ret = scpi_send_message(CMD_SENSOR_VALUE, &id, sizeof(id),
723 				&buf, sizeof(buf));
724 	if (ret)
725 		return ret;
726 
727 	if (scpi_info->is_legacy)
728 		/* only 32-bits supported, hi_val can be junk */
729 		*val = le32_to_cpu(buf.lo_val);
730 	else
731 		*val = (u64)le32_to_cpu(buf.hi_val) << 32 |
732 			le32_to_cpu(buf.lo_val);
733 
734 	return 0;
735 }
736 
737 static int scpi_device_get_power_state(u16 dev_id)
738 {
739 	int ret;
740 	u8 pstate;
741 	__le16 id = cpu_to_le16(dev_id);
742 
743 	ret = scpi_send_message(CMD_GET_DEVICE_PWR_STATE, &id,
744 				sizeof(id), &pstate, sizeof(pstate));
745 	return ret ? ret : pstate;
746 }
747 
748 static int scpi_device_set_power_state(u16 dev_id, u8 pstate)
749 {
750 	int stat;
751 	struct dev_pstate_set dev_set = {
752 		.dev_id = cpu_to_le16(dev_id),
753 		.pstate = pstate,
754 	};
755 
756 	return scpi_send_message(CMD_SET_DEVICE_PWR_STATE, &dev_set,
757 				 sizeof(dev_set), &stat, sizeof(stat));
758 }
759 
760 static struct scpi_ops scpi_ops = {
761 	.get_version = scpi_get_version,
762 	.clk_get_range = scpi_clk_get_range,
763 	.clk_get_val = scpi_clk_get_val,
764 	.clk_set_val = scpi_clk_set_val,
765 	.dvfs_get_idx = scpi_dvfs_get_idx,
766 	.dvfs_set_idx = scpi_dvfs_set_idx,
767 	.dvfs_get_info = scpi_dvfs_get_info,
768 	.sensor_get_capability = scpi_sensor_get_capability,
769 	.sensor_get_info = scpi_sensor_get_info,
770 	.sensor_get_value = scpi_sensor_get_value,
771 	.device_get_power_state = scpi_device_get_power_state,
772 	.device_set_power_state = scpi_device_set_power_state,
773 };
774 
775 struct scpi_ops *get_scpi_ops(void)
776 {
777 	return scpi_info ? scpi_info->scpi_ops : NULL;
778 }
779 EXPORT_SYMBOL_GPL(get_scpi_ops);
780 
781 static int scpi_init_versions(struct scpi_drvinfo *info)
782 {
783 	int ret;
784 	struct scp_capabilities caps;
785 
786 	ret = scpi_send_message(CMD_SCPI_CAPABILITIES, NULL, 0,
787 				&caps, sizeof(caps));
788 	if (!ret) {
789 		info->protocol_version = le32_to_cpu(caps.protocol_version);
790 		info->firmware_version = le32_to_cpu(caps.platform_version);
791 	}
792 	/* Ignore error if not implemented */
793 	if (scpi_info->is_legacy && ret == -EOPNOTSUPP)
794 		return 0;
795 
796 	return ret;
797 }
798 
799 static ssize_t protocol_version_show(struct device *dev,
800 				     struct device_attribute *attr, char *buf)
801 {
802 	struct scpi_drvinfo *scpi_info = dev_get_drvdata(dev);
803 
804 	return sprintf(buf, "%d.%d\n",
805 		       PROTOCOL_REV_MAJOR(scpi_info->protocol_version),
806 		       PROTOCOL_REV_MINOR(scpi_info->protocol_version));
807 }
808 static DEVICE_ATTR_RO(protocol_version);
809 
810 static ssize_t firmware_version_show(struct device *dev,
811 				     struct device_attribute *attr, char *buf)
812 {
813 	struct scpi_drvinfo *scpi_info = dev_get_drvdata(dev);
814 
815 	return sprintf(buf, "%d.%d.%d\n",
816 		       FW_REV_MAJOR(scpi_info->firmware_version),
817 		       FW_REV_MINOR(scpi_info->firmware_version),
818 		       FW_REV_PATCH(scpi_info->firmware_version));
819 }
820 static DEVICE_ATTR_RO(firmware_version);
821 
822 static struct attribute *versions_attrs[] = {
823 	&dev_attr_firmware_version.attr,
824 	&dev_attr_protocol_version.attr,
825 	NULL,
826 };
827 ATTRIBUTE_GROUPS(versions);
828 
829 static void
830 scpi_free_channels(struct device *dev, struct scpi_chan *pchan, int count)
831 {
832 	int i;
833 
834 	for (i = 0; i < count && pchan->chan; i++, pchan++) {
835 		mbox_free_channel(pchan->chan);
836 		devm_kfree(dev, pchan->xfers);
837 		devm_iounmap(dev, pchan->rx_payload);
838 	}
839 }
840 
841 static int scpi_remove(struct platform_device *pdev)
842 {
843 	int i;
844 	struct device *dev = &pdev->dev;
845 	struct scpi_drvinfo *info = platform_get_drvdata(pdev);
846 
847 	scpi_info = NULL; /* stop exporting SCPI ops through get_scpi_ops */
848 
849 	of_platform_depopulate(dev);
850 	sysfs_remove_groups(&dev->kobj, versions_groups);
851 	scpi_free_channels(dev, info->channels, info->num_chans);
852 	platform_set_drvdata(pdev, NULL);
853 
854 	for (i = 0; i < MAX_DVFS_DOMAINS && info->dvfs[i]; i++) {
855 		kfree(info->dvfs[i]->opps);
856 		kfree(info->dvfs[i]);
857 	}
858 	devm_kfree(dev, info->channels);
859 	devm_kfree(dev, info);
860 
861 	return 0;
862 }
863 
864 #define MAX_SCPI_XFERS		10
865 static int scpi_alloc_xfer_list(struct device *dev, struct scpi_chan *ch)
866 {
867 	int i;
868 	struct scpi_xfer *xfers;
869 
870 	xfers = devm_kzalloc(dev, MAX_SCPI_XFERS * sizeof(*xfers), GFP_KERNEL);
871 	if (!xfers)
872 		return -ENOMEM;
873 
874 	ch->xfers = xfers;
875 	for (i = 0; i < MAX_SCPI_XFERS; i++, xfers++)
876 		list_add_tail(&xfers->node, &ch->xfers_list);
877 	return 0;
878 }
879 
880 static const struct of_device_id legacy_scpi_of_match[] = {
881 	{.compatible = "arm,scpi-pre-1.0"},
882 	{},
883 };
884 
885 static int scpi_probe(struct platform_device *pdev)
886 {
887 	int count, idx, ret;
888 	struct resource res;
889 	struct scpi_chan *scpi_chan;
890 	struct device *dev = &pdev->dev;
891 	struct device_node *np = dev->of_node;
892 
893 	scpi_info = devm_kzalloc(dev, sizeof(*scpi_info), GFP_KERNEL);
894 	if (!scpi_info)
895 		return -ENOMEM;
896 
897 	if (of_match_device(legacy_scpi_of_match, &pdev->dev))
898 		scpi_info->is_legacy = true;
899 
900 	count = of_count_phandle_with_args(np, "mboxes", "#mbox-cells");
901 	if (count < 0) {
902 		dev_err(dev, "no mboxes property in '%s'\n", np->full_name);
903 		return -ENODEV;
904 	}
905 
906 	scpi_chan = devm_kcalloc(dev, count, sizeof(*scpi_chan), GFP_KERNEL);
907 	if (!scpi_chan)
908 		return -ENOMEM;
909 
910 	for (idx = 0; idx < count; idx++) {
911 		resource_size_t size;
912 		struct scpi_chan *pchan = scpi_chan + idx;
913 		struct mbox_client *cl = &pchan->cl;
914 		struct device_node *shmem = of_parse_phandle(np, "shmem", idx);
915 
916 		ret = of_address_to_resource(shmem, 0, &res);
917 		of_node_put(shmem);
918 		if (ret) {
919 			dev_err(dev, "failed to get SCPI payload mem resource\n");
920 			goto err;
921 		}
922 
923 		size = resource_size(&res);
924 		pchan->rx_payload = devm_ioremap(dev, res.start, size);
925 		if (!pchan->rx_payload) {
926 			dev_err(dev, "failed to ioremap SCPI payload\n");
927 			ret = -EADDRNOTAVAIL;
928 			goto err;
929 		}
930 		pchan->tx_payload = pchan->rx_payload + (size >> 1);
931 
932 		cl->dev = dev;
933 		cl->rx_callback = scpi_handle_remote_msg;
934 		cl->tx_prepare = scpi_tx_prepare;
935 		cl->tx_block = true;
936 		cl->tx_tout = 20;
937 		cl->knows_txdone = false; /* controller can't ack */
938 
939 		INIT_LIST_HEAD(&pchan->rx_pending);
940 		INIT_LIST_HEAD(&pchan->xfers_list);
941 		spin_lock_init(&pchan->rx_lock);
942 		mutex_init(&pchan->xfers_lock);
943 
944 		ret = scpi_alloc_xfer_list(dev, pchan);
945 		if (!ret) {
946 			pchan->chan = mbox_request_channel(cl, idx);
947 			if (!IS_ERR(pchan->chan))
948 				continue;
949 			ret = PTR_ERR(pchan->chan);
950 			if (ret != -EPROBE_DEFER)
951 				dev_err(dev, "failed to get channel%d err %d\n",
952 					idx, ret);
953 		}
954 err:
955 		scpi_free_channels(dev, scpi_chan, idx);
956 		scpi_info = NULL;
957 		return ret;
958 	}
959 
960 	scpi_info->channels = scpi_chan;
961 	scpi_info->num_chans = count;
962 	scpi_info->commands = scpi_std_commands;
963 
964 	platform_set_drvdata(pdev, scpi_info);
965 
966 	if (scpi_info->is_legacy) {
967 		/* Replace with legacy variants */
968 		scpi_ops.clk_set_val = legacy_scpi_clk_set_val;
969 		scpi_info->commands = scpi_legacy_commands;
970 
971 		/* Fill priority bitmap */
972 		for (idx = 0; idx < ARRAY_SIZE(legacy_hpriority_cmds); idx++)
973 			set_bit(legacy_hpriority_cmds[idx],
974 				scpi_info->cmd_priority);
975 	}
976 
977 	ret = scpi_init_versions(scpi_info);
978 	if (ret) {
979 		dev_err(dev, "incorrect or no SCP firmware found\n");
980 		scpi_remove(pdev);
981 		return ret;
982 	}
983 
984 	_dev_info(dev, "SCP Protocol %d.%d Firmware %d.%d.%d version\n",
985 		  PROTOCOL_REV_MAJOR(scpi_info->protocol_version),
986 		  PROTOCOL_REV_MINOR(scpi_info->protocol_version),
987 		  FW_REV_MAJOR(scpi_info->firmware_version),
988 		  FW_REV_MINOR(scpi_info->firmware_version),
989 		  FW_REV_PATCH(scpi_info->firmware_version));
990 	scpi_info->scpi_ops = &scpi_ops;
991 
992 	ret = sysfs_create_groups(&dev->kobj, versions_groups);
993 	if (ret)
994 		dev_err(dev, "unable to create sysfs version group\n");
995 
996 	return of_platform_populate(dev->of_node, NULL, NULL, dev);
997 }
998 
999 static const struct of_device_id scpi_of_match[] = {
1000 	{.compatible = "arm,scpi"},
1001 	{.compatible = "arm,scpi-pre-1.0"},
1002 	{},
1003 };
1004 
1005 MODULE_DEVICE_TABLE(of, scpi_of_match);
1006 
1007 static struct platform_driver scpi_driver = {
1008 	.driver = {
1009 		.name = "scpi_protocol",
1010 		.of_match_table = scpi_of_match,
1011 	},
1012 	.probe = scpi_probe,
1013 	.remove = scpi_remove,
1014 };
1015 module_platform_driver(scpi_driver);
1016 
1017 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
1018 MODULE_DESCRIPTION("ARM SCPI mailbox protocol driver");
1019 MODULE_LICENSE("GPL v2");
1020