xref: /linux/drivers/soc/ti/wkup_m3_ipc.c (revision 1e0731c05c985deb68a97fa44c1adcd3305dda90)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * AMx3 Wkup M3 IPC driver
4  *
5  * Copyright (C) 2015 Texas Instruments, Inc.
6  *
7  * Dave Gerlach <d-gerlach@ti.com>
8  */
9 
10 #include <linux/debugfs.h>
11 #include <linux/err.h>
12 #include <linux/firmware.h>
13 #include <linux/kernel.h>
14 #include <linux/kthread.h>
15 #include <linux/interrupt.h>
16 #include <linux/irq.h>
17 #include <linux/module.h>
18 #include <linux/of.h>
19 #include <linux/omap-mailbox.h>
20 #include <linux/platform_device.h>
21 #include <linux/remoteproc.h>
22 #include <linux/suspend.h>
23 #include <linux/wkup_m3_ipc.h>
24 
25 #define AM33XX_CTRL_IPC_REG_COUNT	0x8
26 #define AM33XX_CTRL_IPC_REG_OFFSET(m)	(0x4 + 4 * (m))
27 
28 /* AM33XX M3_TXEV_EOI register */
29 #define AM33XX_CONTROL_M3_TXEV_EOI	0x00
30 
31 #define AM33XX_M3_TXEV_ACK		(0x1 << 0)
32 #define AM33XX_M3_TXEV_ENABLE		(0x0 << 0)
33 
34 #define IPC_CMD_DS0			0x4
35 #define IPC_CMD_STANDBY			0xc
36 #define IPC_CMD_IDLE			0x10
37 #define IPC_CMD_RESET			0xe
38 #define DS_IPC_DEFAULT			0xffffffff
39 #define M3_VERSION_UNKNOWN		0x0000ffff
40 #define M3_BASELINE_VERSION		0x191
41 #define M3_STATUS_RESP_MASK		(0xffff << 16)
42 #define M3_FW_VERSION_MASK		0xffff
43 #define M3_WAKE_SRC_MASK		0xff
44 
45 #define IPC_MEM_TYPE_SHIFT		(0x0)
46 #define IPC_MEM_TYPE_MASK		(0x7 << 0)
47 #define IPC_VTT_STAT_SHIFT		(0x3)
48 #define IPC_VTT_STAT_MASK		(0x1 << 3)
49 #define IPC_VTT_GPIO_PIN_SHIFT		(0x4)
50 #define IPC_VTT_GPIO_PIN_MASK		(0x3f << 4)
51 #define IPC_IO_ISOLATION_STAT_SHIFT	(10)
52 #define IPC_IO_ISOLATION_STAT_MASK	(0x1 << 10)
53 
54 #define IPC_DBG_HALT_SHIFT		(11)
55 #define IPC_DBG_HALT_MASK		(0x1 << 11)
56 
57 #define M3_STATE_UNKNOWN		0
58 #define M3_STATE_RESET			1
59 #define M3_STATE_INITED			2
60 #define M3_STATE_MSG_FOR_LP		3
61 #define M3_STATE_MSG_FOR_RESET		4
62 
63 #define WKUP_M3_SD_FW_MAGIC		0x570C
64 
65 #define WKUP_M3_DMEM_START		0x80000
66 #define WKUP_M3_AUXDATA_OFFSET		0x1000
67 #define WKUP_M3_AUXDATA_SIZE		0xFF
68 
69 static struct wkup_m3_ipc *m3_ipc_state;
70 
71 static const struct wkup_m3_wakeup_src wakeups[] = {
72 	{.irq_nr = 16,	.src = "PRCM"},
73 	{.irq_nr = 35,	.src = "USB0_PHY"},
74 	{.irq_nr = 36,	.src = "USB1_PHY"},
75 	{.irq_nr = 40,	.src = "I2C0"},
76 	{.irq_nr = 41,	.src = "RTC Timer"},
77 	{.irq_nr = 42,	.src = "RTC Alarm"},
78 	{.irq_nr = 43,	.src = "Timer0"},
79 	{.irq_nr = 44,	.src = "Timer1"},
80 	{.irq_nr = 45,	.src = "UART"},
81 	{.irq_nr = 46,	.src = "GPIO0"},
82 	{.irq_nr = 48,	.src = "MPU_WAKE"},
83 	{.irq_nr = 49,	.src = "WDT0"},
84 	{.irq_nr = 50,	.src = "WDT1"},
85 	{.irq_nr = 51,	.src = "ADC_TSC"},
86 	{.irq_nr = 0,	.src = "Unknown"},
87 };
88 
89 /**
90  * wkup_m3_copy_aux_data - Copy auxiliary data to special region of m3 dmem
91  * @data - pointer to data
92  * @sz - size of data to copy (limit 256 bytes)
93  *
94  * Copies any additional blob of data to the wkup_m3 dmem to be used by the
95  * firmware
96  */
97 static unsigned long wkup_m3_copy_aux_data(struct wkup_m3_ipc *m3_ipc,
98 					   const void *data, int sz)
99 {
100 	unsigned long aux_data_dev_addr;
101 	void *aux_data_addr;
102 
103 	aux_data_dev_addr = WKUP_M3_DMEM_START + WKUP_M3_AUXDATA_OFFSET;
104 	aux_data_addr = rproc_da_to_va(m3_ipc->rproc,
105 				       aux_data_dev_addr,
106 				       WKUP_M3_AUXDATA_SIZE,
107 				       NULL);
108 	memcpy(aux_data_addr, data, sz);
109 
110 	return WKUP_M3_AUXDATA_OFFSET;
111 }
112 
113 static void wkup_m3_scale_data_fw_cb(const struct firmware *fw, void *context)
114 {
115 	unsigned long val, aux_base;
116 	struct wkup_m3_scale_data_header hdr;
117 	struct wkup_m3_ipc *m3_ipc = context;
118 	struct device *dev = m3_ipc->dev;
119 
120 	if (!fw) {
121 		dev_err(dev, "Voltage scale fw name given but file missing.\n");
122 		return;
123 	}
124 
125 	memcpy(&hdr, fw->data, sizeof(hdr));
126 
127 	if (hdr.magic != WKUP_M3_SD_FW_MAGIC) {
128 		dev_err(dev, "PM: Voltage Scale Data binary does not appear valid.\n");
129 		goto release_sd_fw;
130 	}
131 
132 	aux_base = wkup_m3_copy_aux_data(m3_ipc, fw->data + sizeof(hdr),
133 					 fw->size - sizeof(hdr));
134 
135 	val = (aux_base + hdr.sleep_offset);
136 	val |= ((aux_base + hdr.wake_offset) << 16);
137 
138 	m3_ipc->volt_scale_offsets = val;
139 
140 release_sd_fw:
141 	release_firmware(fw);
142 };
143 
144 static int wkup_m3_init_scale_data(struct wkup_m3_ipc *m3_ipc,
145 				   struct device *dev)
146 {
147 	int ret = 0;
148 
149 	/*
150 	 * If no name is provided, user has already been warned, pm will
151 	 * still work so return 0
152 	 */
153 
154 	if (!m3_ipc->sd_fw_name)
155 		return ret;
156 
157 	ret = request_firmware_nowait(THIS_MODULE, FW_ACTION_UEVENT,
158 				      m3_ipc->sd_fw_name, dev, GFP_ATOMIC,
159 				      m3_ipc, wkup_m3_scale_data_fw_cb);
160 
161 	return ret;
162 }
163 
164 #ifdef CONFIG_DEBUG_FS
165 static void wkup_m3_set_halt_late(bool enabled)
166 {
167 	if (enabled)
168 		m3_ipc_state->halt = (1 << IPC_DBG_HALT_SHIFT);
169 	else
170 		m3_ipc_state->halt = 0;
171 }
172 
173 static int option_get(void *data, u64 *val)
174 {
175 	u32 *option = data;
176 
177 	*val = *option;
178 
179 	return 0;
180 }
181 
182 static int option_set(void *data, u64 val)
183 {
184 	u32 *option = data;
185 
186 	*option = val;
187 
188 	if (option == &m3_ipc_state->halt) {
189 		if (val)
190 			wkup_m3_set_halt_late(true);
191 		else
192 			wkup_m3_set_halt_late(false);
193 	}
194 
195 	return 0;
196 }
197 
198 DEFINE_SIMPLE_ATTRIBUTE(wkup_m3_ipc_option_fops, option_get, option_set,
199 			"%llu\n");
200 
201 static int wkup_m3_ipc_dbg_init(struct wkup_m3_ipc *m3_ipc)
202 {
203 	m3_ipc->dbg_path = debugfs_create_dir("wkup_m3_ipc", NULL);
204 
205 	if (IS_ERR(m3_ipc->dbg_path))
206 		return -EINVAL;
207 
208 	(void)debugfs_create_file("enable_late_halt", 0644,
209 				  m3_ipc->dbg_path,
210 				  &m3_ipc->halt,
211 				  &wkup_m3_ipc_option_fops);
212 
213 	return 0;
214 }
215 
216 static inline void wkup_m3_ipc_dbg_destroy(struct wkup_m3_ipc *m3_ipc)
217 {
218 	debugfs_remove_recursive(m3_ipc->dbg_path);
219 }
220 #else
221 static inline int wkup_m3_ipc_dbg_init(struct wkup_m3_ipc *m3_ipc)
222 {
223 	return 0;
224 }
225 
226 static inline void wkup_m3_ipc_dbg_destroy(struct wkup_m3_ipc *m3_ipc)
227 {
228 }
229 #endif /* CONFIG_DEBUG_FS */
230 
231 static void am33xx_txev_eoi(struct wkup_m3_ipc *m3_ipc)
232 {
233 	writel(AM33XX_M3_TXEV_ACK,
234 	       m3_ipc->ipc_mem_base + AM33XX_CONTROL_M3_TXEV_EOI);
235 }
236 
237 static void am33xx_txev_enable(struct wkup_m3_ipc *m3_ipc)
238 {
239 	writel(AM33XX_M3_TXEV_ENABLE,
240 	       m3_ipc->ipc_mem_base + AM33XX_CONTROL_M3_TXEV_EOI);
241 }
242 
243 static void wkup_m3_ctrl_ipc_write(struct wkup_m3_ipc *m3_ipc,
244 				   u32 val, int ipc_reg_num)
245 {
246 	if (WARN(ipc_reg_num < 0 || ipc_reg_num > AM33XX_CTRL_IPC_REG_COUNT,
247 		 "ipc register operation out of range"))
248 		return;
249 
250 	writel(val, m3_ipc->ipc_mem_base +
251 	       AM33XX_CTRL_IPC_REG_OFFSET(ipc_reg_num));
252 }
253 
254 static unsigned int wkup_m3_ctrl_ipc_read(struct wkup_m3_ipc *m3_ipc,
255 					  int ipc_reg_num)
256 {
257 	if (WARN(ipc_reg_num < 0 || ipc_reg_num > AM33XX_CTRL_IPC_REG_COUNT,
258 		 "ipc register operation out of range"))
259 		return 0;
260 
261 	return readl(m3_ipc->ipc_mem_base +
262 		     AM33XX_CTRL_IPC_REG_OFFSET(ipc_reg_num));
263 }
264 
265 static int wkup_m3_fw_version_read(struct wkup_m3_ipc *m3_ipc)
266 {
267 	int val;
268 
269 	val = wkup_m3_ctrl_ipc_read(m3_ipc, 2);
270 
271 	return val & M3_FW_VERSION_MASK;
272 }
273 
274 static irqreturn_t wkup_m3_txev_handler(int irq, void *ipc_data)
275 {
276 	struct wkup_m3_ipc *m3_ipc = ipc_data;
277 	struct device *dev = m3_ipc->dev;
278 	int ver = 0;
279 
280 	am33xx_txev_eoi(m3_ipc);
281 
282 	switch (m3_ipc->state) {
283 	case M3_STATE_RESET:
284 		ver = wkup_m3_fw_version_read(m3_ipc);
285 
286 		if (ver == M3_VERSION_UNKNOWN ||
287 		    ver < M3_BASELINE_VERSION) {
288 			dev_warn(dev, "CM3 Firmware Version %x not supported\n",
289 				 ver);
290 		} else {
291 			dev_info(dev, "CM3 Firmware Version = 0x%x\n", ver);
292 		}
293 
294 		m3_ipc->state = M3_STATE_INITED;
295 		wkup_m3_init_scale_data(m3_ipc, dev);
296 		complete(&m3_ipc->sync_complete);
297 		break;
298 	case M3_STATE_MSG_FOR_RESET:
299 		m3_ipc->state = M3_STATE_INITED;
300 		complete(&m3_ipc->sync_complete);
301 		break;
302 	case M3_STATE_MSG_FOR_LP:
303 		complete(&m3_ipc->sync_complete);
304 		break;
305 	case M3_STATE_UNKNOWN:
306 		dev_warn(dev, "Unknown CM3 State\n");
307 	}
308 
309 	am33xx_txev_enable(m3_ipc);
310 
311 	return IRQ_HANDLED;
312 }
313 
314 static int wkup_m3_ping(struct wkup_m3_ipc *m3_ipc)
315 {
316 	struct device *dev = m3_ipc->dev;
317 	mbox_msg_t dummy_msg = 0;
318 	int ret;
319 
320 	if (!m3_ipc->mbox) {
321 		dev_err(dev,
322 			"No IPC channel to communicate with wkup_m3!\n");
323 		return -EIO;
324 	}
325 
326 	/*
327 	 * Write a dummy message to the mailbox in order to trigger the RX
328 	 * interrupt to alert the M3 that data is available in the IPC
329 	 * registers. We must enable the IRQ here and disable it after in
330 	 * the RX callback to avoid multiple interrupts being received
331 	 * by the CM3.
332 	 */
333 	ret = mbox_send_message(m3_ipc->mbox, &dummy_msg);
334 	if (ret < 0) {
335 		dev_err(dev, "%s: mbox_send_message() failed: %d\n",
336 			__func__, ret);
337 		return ret;
338 	}
339 
340 	ret = wait_for_completion_timeout(&m3_ipc->sync_complete,
341 					  msecs_to_jiffies(500));
342 	if (!ret) {
343 		dev_err(dev, "MPU<->CM3 sync failure\n");
344 		m3_ipc->state = M3_STATE_UNKNOWN;
345 		return -EIO;
346 	}
347 
348 	mbox_client_txdone(m3_ipc->mbox, 0);
349 	return 0;
350 }
351 
352 static int wkup_m3_ping_noirq(struct wkup_m3_ipc *m3_ipc)
353 {
354 	struct device *dev = m3_ipc->dev;
355 	mbox_msg_t dummy_msg = 0;
356 	int ret;
357 
358 	if (!m3_ipc->mbox) {
359 		dev_err(dev,
360 			"No IPC channel to communicate with wkup_m3!\n");
361 		return -EIO;
362 	}
363 
364 	ret = mbox_send_message(m3_ipc->mbox, &dummy_msg);
365 	if (ret < 0) {
366 		dev_err(dev, "%s: mbox_send_message() failed: %d\n",
367 			__func__, ret);
368 		return ret;
369 	}
370 
371 	mbox_client_txdone(m3_ipc->mbox, 0);
372 	return 0;
373 }
374 
375 static int wkup_m3_is_available(struct wkup_m3_ipc *m3_ipc)
376 {
377 	return ((m3_ipc->state != M3_STATE_RESET) &&
378 		(m3_ipc->state != M3_STATE_UNKNOWN));
379 }
380 
381 static void wkup_m3_set_vtt_gpio(struct wkup_m3_ipc *m3_ipc, int gpio)
382 {
383 	m3_ipc->vtt_conf = (1 << IPC_VTT_STAT_SHIFT) |
384 			    (gpio << IPC_VTT_GPIO_PIN_SHIFT);
385 }
386 
387 static void wkup_m3_set_io_isolation(struct wkup_m3_ipc *m3_ipc)
388 {
389 	m3_ipc->isolation_conf = (1 << IPC_IO_ISOLATION_STAT_SHIFT);
390 }
391 
392 /* Public functions */
393 /**
394  * wkup_m3_set_mem_type - Pass wkup_m3 which type of memory is in use
395  * @m3_ipc: Pointer to wkup_m3_ipc context
396  * @mem_type: memory type value read directly from emif
397  *
398  * wkup_m3 must know what memory type is in use to properly suspend
399  * and resume.
400  */
401 static void wkup_m3_set_mem_type(struct wkup_m3_ipc *m3_ipc, int mem_type)
402 {
403 	m3_ipc->mem_type = mem_type;
404 }
405 
406 /**
407  * wkup_m3_set_resume_address - Pass wkup_m3 resume address
408  * @m3_ipc: Pointer to wkup_m3_ipc context
409  * @addr: Physical address from which resume code should execute
410  */
411 static void wkup_m3_set_resume_address(struct wkup_m3_ipc *m3_ipc, void *addr)
412 {
413 	m3_ipc->resume_addr = (unsigned long)addr;
414 }
415 
416 /**
417  * wkup_m3_request_pm_status - Retrieve wkup_m3 status code after suspend
418  * @m3_ipc: Pointer to wkup_m3_ipc context
419  *
420  * Returns code representing the status of a low power mode transition.
421  *	0 - Successful transition
422  *	1 - Failure to transition to low power state
423  */
424 static int wkup_m3_request_pm_status(struct wkup_m3_ipc *m3_ipc)
425 {
426 	unsigned int i;
427 	int val;
428 
429 	val = wkup_m3_ctrl_ipc_read(m3_ipc, 1);
430 
431 	i = M3_STATUS_RESP_MASK & val;
432 	i >>= __ffs(M3_STATUS_RESP_MASK);
433 
434 	return i;
435 }
436 
437 /**
438  * wkup_m3_prepare_low_power - Request preparation for transition to
439  *			       low power state
440  * @m3_ipc: Pointer to wkup_m3_ipc context
441  * @state: A kernel suspend state to enter, either MEM or STANDBY
442  *
443  * Returns 0 if preparation was successful, otherwise returns error code
444  */
445 static int wkup_m3_prepare_low_power(struct wkup_m3_ipc *m3_ipc, int state)
446 {
447 	struct device *dev = m3_ipc->dev;
448 	int m3_power_state;
449 	int ret = 0;
450 
451 	if (!wkup_m3_is_available(m3_ipc))
452 		return -ENODEV;
453 
454 	switch (state) {
455 	case WKUP_M3_DEEPSLEEP:
456 		m3_power_state = IPC_CMD_DS0;
457 		wkup_m3_ctrl_ipc_write(m3_ipc, m3_ipc->volt_scale_offsets, 5);
458 		break;
459 	case WKUP_M3_STANDBY:
460 		m3_power_state = IPC_CMD_STANDBY;
461 		wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 5);
462 		break;
463 	case WKUP_M3_IDLE:
464 		m3_power_state = IPC_CMD_IDLE;
465 		wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 5);
466 		break;
467 	default:
468 		return 1;
469 	}
470 
471 	/* Program each required IPC register then write defaults to others */
472 	wkup_m3_ctrl_ipc_write(m3_ipc, m3_ipc->resume_addr, 0);
473 	wkup_m3_ctrl_ipc_write(m3_ipc, m3_power_state, 1);
474 	wkup_m3_ctrl_ipc_write(m3_ipc, m3_ipc->mem_type |
475 			       m3_ipc->vtt_conf |
476 			       m3_ipc->isolation_conf |
477 			       m3_ipc->halt, 4);
478 
479 	wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 2);
480 	wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 3);
481 	wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 6);
482 	wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 7);
483 
484 	m3_ipc->state = M3_STATE_MSG_FOR_LP;
485 
486 	if (state == WKUP_M3_IDLE)
487 		ret = wkup_m3_ping_noirq(m3_ipc);
488 	else
489 		ret = wkup_m3_ping(m3_ipc);
490 
491 	if (ret) {
492 		dev_err(dev, "Unable to ping CM3\n");
493 		return ret;
494 	}
495 
496 	return 0;
497 }
498 
499 /**
500  * wkup_m3_finish_low_power - Return m3 to reset state
501  * @m3_ipc: Pointer to wkup_m3_ipc context
502  *
503  * Returns 0 if reset was successful, otherwise returns error code
504  */
505 static int wkup_m3_finish_low_power(struct wkup_m3_ipc *m3_ipc)
506 {
507 	struct device *dev = m3_ipc->dev;
508 	int ret = 0;
509 
510 	if (!wkup_m3_is_available(m3_ipc))
511 		return -ENODEV;
512 
513 	wkup_m3_ctrl_ipc_write(m3_ipc, IPC_CMD_RESET, 1);
514 	wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 2);
515 
516 	m3_ipc->state = M3_STATE_MSG_FOR_RESET;
517 
518 	ret = wkup_m3_ping(m3_ipc);
519 	if (ret) {
520 		dev_err(dev, "Unable to ping CM3\n");
521 		return ret;
522 	}
523 
524 	return 0;
525 }
526 
527 /**
528  * wkup_m3_request_wake_src - Get the wakeup source info passed from wkup_m3
529  * @m3_ipc: Pointer to wkup_m3_ipc context
530  */
531 static const char *wkup_m3_request_wake_src(struct wkup_m3_ipc *m3_ipc)
532 {
533 	unsigned int wakeup_src_idx;
534 	int j, val;
535 
536 	val = wkup_m3_ctrl_ipc_read(m3_ipc, 6);
537 
538 	wakeup_src_idx = val & M3_WAKE_SRC_MASK;
539 
540 	for (j = 0; j < ARRAY_SIZE(wakeups) - 1; j++) {
541 		if (wakeups[j].irq_nr == wakeup_src_idx)
542 			return wakeups[j].src;
543 	}
544 	return wakeups[j].src;
545 }
546 
547 /**
548  * wkup_m3_set_rtc_only - Set the rtc_only flag
549  * @m3_ipc: Pointer to wkup_m3_ipc context
550  */
551 static void wkup_m3_set_rtc_only(struct wkup_m3_ipc *m3_ipc)
552 {
553 	if (m3_ipc_state)
554 		m3_ipc_state->is_rtc_only = true;
555 }
556 
557 static struct wkup_m3_ipc_ops ipc_ops = {
558 	.set_mem_type = wkup_m3_set_mem_type,
559 	.set_resume_address = wkup_m3_set_resume_address,
560 	.prepare_low_power = wkup_m3_prepare_low_power,
561 	.finish_low_power = wkup_m3_finish_low_power,
562 	.request_pm_status = wkup_m3_request_pm_status,
563 	.request_wake_src = wkup_m3_request_wake_src,
564 	.set_rtc_only = wkup_m3_set_rtc_only,
565 };
566 
567 /**
568  * wkup_m3_ipc_get - Return handle to wkup_m3_ipc
569  *
570  * Returns NULL if the wkup_m3 is not yet available, otherwise returns
571  * pointer to wkup_m3_ipc struct.
572  */
573 struct wkup_m3_ipc *wkup_m3_ipc_get(void)
574 {
575 	if (m3_ipc_state)
576 		get_device(m3_ipc_state->dev);
577 	else
578 		return NULL;
579 
580 	return m3_ipc_state;
581 }
582 EXPORT_SYMBOL_GPL(wkup_m3_ipc_get);
583 
584 /**
585  * wkup_m3_ipc_put - Free handle to wkup_m3_ipc returned from wkup_m3_ipc_get
586  * @m3_ipc: A pointer to wkup_m3_ipc struct returned by wkup_m3_ipc_get
587  */
588 void wkup_m3_ipc_put(struct wkup_m3_ipc *m3_ipc)
589 {
590 	if (m3_ipc_state)
591 		put_device(m3_ipc_state->dev);
592 }
593 EXPORT_SYMBOL_GPL(wkup_m3_ipc_put);
594 
595 static int wkup_m3_rproc_boot_thread(void *arg)
596 {
597 	struct wkup_m3_ipc *m3_ipc = arg;
598 	struct device *dev = m3_ipc->dev;
599 	int ret;
600 
601 	init_completion(&m3_ipc->sync_complete);
602 
603 	ret = rproc_boot(m3_ipc->rproc);
604 	if (ret)
605 		dev_err(dev, "rproc_boot failed\n");
606 	else
607 		m3_ipc_state = m3_ipc;
608 
609 	return 0;
610 }
611 
612 static int wkup_m3_ipc_probe(struct platform_device *pdev)
613 {
614 	struct device *dev = &pdev->dev;
615 	int irq, ret, temp;
616 	phandle rproc_phandle;
617 	struct rproc *m3_rproc;
618 	struct task_struct *task;
619 	struct wkup_m3_ipc *m3_ipc;
620 	struct device_node *np = dev->of_node;
621 
622 	m3_ipc = devm_kzalloc(dev, sizeof(*m3_ipc), GFP_KERNEL);
623 	if (!m3_ipc)
624 		return -ENOMEM;
625 
626 	m3_ipc->ipc_mem_base = devm_platform_ioremap_resource(pdev, 0);
627 	if (IS_ERR(m3_ipc->ipc_mem_base))
628 		return PTR_ERR(m3_ipc->ipc_mem_base);
629 
630 	irq = platform_get_irq(pdev, 0);
631 	if (irq < 0)
632 		return irq;
633 
634 	ret = devm_request_irq(dev, irq, wkup_m3_txev_handler,
635 			       0, "wkup_m3_txev", m3_ipc);
636 	if (ret) {
637 		dev_err(dev, "request_irq failed\n");
638 		return ret;
639 	}
640 
641 	m3_ipc->mbox_client.dev = dev;
642 	m3_ipc->mbox_client.tx_done = NULL;
643 	m3_ipc->mbox_client.tx_prepare = NULL;
644 	m3_ipc->mbox_client.rx_callback = NULL;
645 	m3_ipc->mbox_client.tx_block = false;
646 	m3_ipc->mbox_client.knows_txdone = false;
647 
648 	m3_ipc->mbox = mbox_request_channel(&m3_ipc->mbox_client, 0);
649 
650 	if (IS_ERR(m3_ipc->mbox)) {
651 		dev_err(dev, "IPC Request for A8->M3 Channel failed! %ld\n",
652 			PTR_ERR(m3_ipc->mbox));
653 		return PTR_ERR(m3_ipc->mbox);
654 	}
655 
656 	if (of_property_read_u32(dev->of_node, "ti,rproc", &rproc_phandle)) {
657 		dev_err(&pdev->dev, "could not get rproc phandle\n");
658 		ret = -ENODEV;
659 		goto err_free_mbox;
660 	}
661 
662 	m3_rproc = rproc_get_by_phandle(rproc_phandle);
663 	if (!m3_rproc) {
664 		dev_err(&pdev->dev, "could not get rproc handle\n");
665 		ret = -EPROBE_DEFER;
666 		goto err_free_mbox;
667 	}
668 
669 	m3_ipc->rproc = m3_rproc;
670 	m3_ipc->dev = dev;
671 	m3_ipc->state = M3_STATE_RESET;
672 
673 	m3_ipc->ops = &ipc_ops;
674 
675 	if (!of_property_read_u32(np, "ti,vtt-gpio-pin", &temp)) {
676 		if (temp >= 0 && temp <= 31)
677 			wkup_m3_set_vtt_gpio(m3_ipc, temp);
678 		else
679 			dev_warn(dev, "Invalid VTT GPIO(%d) pin\n", temp);
680 	}
681 
682 	if (of_property_read_bool(np, "ti,set-io-isolation"))
683 		wkup_m3_set_io_isolation(m3_ipc);
684 
685 	ret = of_property_read_string(np, "firmware-name",
686 				      &m3_ipc->sd_fw_name);
687 	if (ret) {
688 		dev_dbg(dev, "Voltage scaling data blob not provided from DT.\n");
689 	}
690 
691 	/*
692 	 * Wait for firmware loading completion in a thread so we
693 	 * can boot the wkup_m3 as soon as it's ready without holding
694 	 * up kernel boot
695 	 */
696 	task = kthread_run(wkup_m3_rproc_boot_thread, m3_ipc,
697 			   "wkup_m3_rproc_loader");
698 
699 	if (IS_ERR(task)) {
700 		dev_err(dev, "can't create rproc_boot thread\n");
701 		ret = PTR_ERR(task);
702 		goto err_put_rproc;
703 	}
704 
705 	wkup_m3_ipc_dbg_init(m3_ipc);
706 
707 	return 0;
708 
709 err_put_rproc:
710 	rproc_put(m3_rproc);
711 err_free_mbox:
712 	mbox_free_channel(m3_ipc->mbox);
713 	return ret;
714 }
715 
716 static int wkup_m3_ipc_remove(struct platform_device *pdev)
717 {
718 	wkup_m3_ipc_dbg_destroy(m3_ipc_state);
719 
720 	mbox_free_channel(m3_ipc_state->mbox);
721 
722 	rproc_shutdown(m3_ipc_state->rproc);
723 	rproc_put(m3_ipc_state->rproc);
724 
725 	m3_ipc_state = NULL;
726 
727 	return 0;
728 }
729 
730 static int __maybe_unused wkup_m3_ipc_suspend(struct device *dev)
731 {
732 	/*
733 	 * Nothing needs to be done on suspend even with rtc_only flag set
734 	 */
735 	return 0;
736 }
737 
738 static int __maybe_unused wkup_m3_ipc_resume(struct device *dev)
739 {
740 	if (m3_ipc_state->is_rtc_only) {
741 		rproc_shutdown(m3_ipc_state->rproc);
742 		rproc_boot(m3_ipc_state->rproc);
743 	}
744 
745 	m3_ipc_state->is_rtc_only = false;
746 
747 	return 0;
748 }
749 
750 static const struct dev_pm_ops wkup_m3_ipc_pm_ops = {
751 	SET_SYSTEM_SLEEP_PM_OPS(wkup_m3_ipc_suspend, wkup_m3_ipc_resume)
752 };
753 
754 static const struct of_device_id wkup_m3_ipc_of_match[] = {
755 	{ .compatible = "ti,am3352-wkup-m3-ipc", },
756 	{ .compatible = "ti,am4372-wkup-m3-ipc", },
757 	{},
758 };
759 MODULE_DEVICE_TABLE(of, wkup_m3_ipc_of_match);
760 
761 static struct platform_driver wkup_m3_ipc_driver = {
762 	.probe = wkup_m3_ipc_probe,
763 	.remove = wkup_m3_ipc_remove,
764 	.driver = {
765 		.name = "wkup_m3_ipc",
766 		.of_match_table = wkup_m3_ipc_of_match,
767 		.pm = &wkup_m3_ipc_pm_ops,
768 	},
769 };
770 
771 module_platform_driver(wkup_m3_ipc_driver);
772 
773 MODULE_LICENSE("GPL v2");
774 MODULE_DESCRIPTION("wkup m3 remote processor ipc driver");
775 MODULE_AUTHOR("Dave Gerlach <d-gerlach@ti.com>");
776