1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * PowerMac G5 SMU driver
4 *
5 * Copyright 2004 J. Mayer <l_indien@magic.fr>
6 * Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
7 */
8
9/*
10 * TODO:
11 *  - maybe add timeout to commands ?
12 *  - blocking version of time functions
13 *  - polling version of i2c commands (including timer that works with
14 *    interrupts off)
15 *  - maybe avoid some data copies with i2c by directly using the smu cmd
16 *    buffer and a lower level internal interface
17 *  - understand SMU -> CPU events and implement reception of them via
18 *    the userland interface
19 */
20
21#include <linux/types.h>
22#include <linux/kernel.h>
23#include <linux/device.h>
24#include <linux/dmapool.h>
25#include <linux/memblock.h>
26#include <linux/vmalloc.h>
27#include <linux/highmem.h>
28#include <linux/jiffies.h>
29#include <linux/interrupt.h>
30#include <linux/rtc.h>
31#include <linux/completion.h>
32#include <linux/miscdevice.h>
33#include <linux/delay.h>
34#include <linux/poll.h>
35#include <linux/mutex.h>
36#include <linux/of_device.h>
37#include <linux/of_irq.h>
38#include <linux/of_platform.h>
39#include <linux/slab.h>
40#include <linux/sched/signal.h>
41
42#include <asm/byteorder.h>
43#include <asm/io.h>
44#include <asm/prom.h>
45#include <asm/machdep.h>
46#include <asm/pmac_feature.h>
47#include <asm/smu.h>
48#include <asm/sections.h>
49#include <linux/uaccess.h>
50
51#define VERSION "0.7"
52#define AUTHOR  "(c) 2005 Benjamin Herrenschmidt, IBM Corp."
53
54#undef DEBUG_SMU
55
56#ifdef DEBUG_SMU
57#define DPRINTK(fmt, args...) do { printk(KERN_DEBUG fmt , ##args); } while (0)
58#else
59#define DPRINTK(fmt, args...) do { } while (0)
60#endif
61
62/*
63 * This is the command buffer passed to the SMU hardware
64 */
65#define SMU_MAX_DATA	254
66
67struct smu_cmd_buf {
68	u8 cmd;
69	u8 length;
70	u8 data[SMU_MAX_DATA];
71};
72
73struct smu_device {
74	spinlock_t		lock;
75	struct device_node	*of_node;
76	struct platform_device	*of_dev;
77	int			doorbell;	/* doorbell gpio */
78	u32 __iomem		*db_buf;	/* doorbell buffer */
79	struct device_node	*db_node;
80	unsigned int		db_irq;
81	int			msg;
82	struct device_node	*msg_node;
83	unsigned int		msg_irq;
84	struct smu_cmd_buf	*cmd_buf;	/* command buffer virtual */
85	u32			cmd_buf_abs;	/* command buffer absolute */
86	struct list_head	cmd_list;
87	struct smu_cmd		*cmd_cur;	/* pending command */
88	int			broken_nap;
89	struct list_head	cmd_i2c_list;
90	struct smu_i2c_cmd	*cmd_i2c_cur;	/* pending i2c command */
91	struct timer_list	i2c_timer;
92};
93
94/*
95 * I don't think there will ever be more than one SMU, so
96 * for now, just hard code that
97 */
98static DEFINE_MUTEX(smu_mutex);
99static struct smu_device	*smu;
100static DEFINE_MUTEX(smu_part_access);
101static int smu_irq_inited;
102static unsigned long smu_cmdbuf_abs;
103
104static void smu_i2c_retry(struct timer_list *t);
105
106/*
107 * SMU driver low level stuff
108 */
109
110static void smu_start_cmd(void)
111{
112	unsigned long faddr, fend;
113	struct smu_cmd *cmd;
114
115	if (list_empty(&smu->cmd_list))
116		return;
117
118	/* Fetch first command in queue */
119	cmd = list_entry(smu->cmd_list.next, struct smu_cmd, link);
120	smu->cmd_cur = cmd;
121	list_del(&cmd->link);
122
123	DPRINTK("SMU: starting cmd %x, %d bytes data\n", cmd->cmd,
124		cmd->data_len);
125	DPRINTK("SMU: data buffer: %8ph\n", cmd->data_buf);
126
127	/* Fill the SMU command buffer */
128	smu->cmd_buf->cmd = cmd->cmd;
129	smu->cmd_buf->length = cmd->data_len;
130	memcpy(smu->cmd_buf->data, cmd->data_buf, cmd->data_len);
131
132	/* Flush command and data to RAM */
133	faddr = (unsigned long)smu->cmd_buf;
134	fend = faddr + smu->cmd_buf->length + 2;
135	flush_dcache_range(faddr, fend);
136
137
138	/* We also disable NAP mode for the duration of the command
139	 * on U3 based machines.
140	 * This is slightly racy as it can be written back to 1 by a sysctl
141	 * but that never happens in practice. There seem to be an issue with
142	 * U3 based machines such as the iMac G5 where napping for the
143	 * whole duration of the command prevents the SMU from fetching it
144	 * from memory. This might be related to the strange i2c based
145	 * mechanism the SMU uses to access memory.
146	 */
147	if (smu->broken_nap)
148		powersave_nap = 0;
149
150	/* This isn't exactly a DMA mapping here, I suspect
151	 * the SMU is actually communicating with us via i2c to the
152	 * northbridge or the CPU to access RAM.
153	 */
154	writel(smu->cmd_buf_abs, smu->db_buf);
155
156	/* Ring the SMU doorbell */
157	pmac_do_feature_call(PMAC_FTR_WRITE_GPIO, NULL, smu->doorbell, 4);
158}
159
160
161static irqreturn_t smu_db_intr(int irq, void *arg)
162{
163	unsigned long flags;
164	struct smu_cmd *cmd;
165	void (*done)(struct smu_cmd *cmd, void *misc) = NULL;
166	void *misc = NULL;
167	u8 gpio;
168	int rc = 0;
169
170	/* SMU completed the command, well, we hope, let's make sure
171	 * of it
172	 */
173	spin_lock_irqsave(&smu->lock, flags);
174
175	gpio = pmac_do_feature_call(PMAC_FTR_READ_GPIO, NULL, smu->doorbell);
176	if ((gpio & 7) != 7) {
177		spin_unlock_irqrestore(&smu->lock, flags);
178		return IRQ_HANDLED;
179	}
180
181	cmd = smu->cmd_cur;
182	smu->cmd_cur = NULL;
183	if (cmd == NULL)
184		goto bail;
185
186	if (rc == 0) {
187		unsigned long faddr;
188		int reply_len;
189		u8 ack;
190
191		/* CPU might have brought back the cache line, so we need
192		 * to flush again before peeking at the SMU response. We
193		 * flush the entire buffer for now as we haven't read the
194		 * reply length (it's only 2 cache lines anyway)
195		 */
196		faddr = (unsigned long)smu->cmd_buf;
197		flush_dcache_range(faddr, faddr + 256);
198
199		/* Now check ack */
200		ack = (~cmd->cmd) & 0xff;
201		if (ack != smu->cmd_buf->cmd) {
202			DPRINTK("SMU: incorrect ack, want %x got %x\n",
203				ack, smu->cmd_buf->cmd);
204			rc = -EIO;
205		}
206		reply_len = rc == 0 ? smu->cmd_buf->length : 0;
207		DPRINTK("SMU: reply len: %d\n", reply_len);
208		if (reply_len > cmd->reply_len) {
209			printk(KERN_WARNING "SMU: reply buffer too small,"
210			       "got %d bytes for a %d bytes buffer\n",
211			       reply_len, cmd->reply_len);
212			reply_len = cmd->reply_len;
213		}
214		cmd->reply_len = reply_len;
215		if (cmd->reply_buf && reply_len)
216			memcpy(cmd->reply_buf, smu->cmd_buf->data, reply_len);
217	}
218
219	/* Now complete the command. Write status last in order as we lost
220	 * ownership of the command structure as soon as it's no longer -1
221	 */
222	done = cmd->done;
223	misc = cmd->misc;
224	mb();
225	cmd->status = rc;
226
227	/* Re-enable NAP mode */
228	if (smu->broken_nap)
229		powersave_nap = 1;
230 bail:
231	/* Start next command if any */
232	smu_start_cmd();
233	spin_unlock_irqrestore(&smu->lock, flags);
234
235	/* Call command completion handler if any */
236	if (done)
237		done(cmd, misc);
238
239	/* It's an edge interrupt, nothing to do */
240	return IRQ_HANDLED;
241}
242
243
244static irqreturn_t smu_msg_intr(int irq, void *arg)
245{
246	/* I don't quite know what to do with this one, we seem to never
247	 * receive it, so I suspect we have to arm it someway in the SMU
248	 * to start getting events that way.
249	 */
250
251	printk(KERN_INFO "SMU: message interrupt !\n");
252
253	/* It's an edge interrupt, nothing to do */
254	return IRQ_HANDLED;
255}
256
257
258/*
259 * Queued command management.
260 *
261 */
262
263int smu_queue_cmd(struct smu_cmd *cmd)
264{
265	unsigned long flags;
266
267	if (smu == NULL)
268		return -ENODEV;
269	if (cmd->data_len > SMU_MAX_DATA ||
270	    cmd->reply_len > SMU_MAX_DATA)
271		return -EINVAL;
272
273	cmd->status = 1;
274	spin_lock_irqsave(&smu->lock, flags);
275	list_add_tail(&cmd->link, &smu->cmd_list);
276	if (smu->cmd_cur == NULL)
277		smu_start_cmd();
278	spin_unlock_irqrestore(&smu->lock, flags);
279
280	/* Workaround for early calls when irq isn't available */
281	if (!smu_irq_inited || !smu->db_irq)
282		smu_spinwait_cmd(cmd);
283
284	return 0;
285}
286EXPORT_SYMBOL(smu_queue_cmd);
287
288
289int smu_queue_simple(struct smu_simple_cmd *scmd, u8 command,
290		     unsigned int data_len,
291		     void (*done)(struct smu_cmd *cmd, void *misc),
292		     void *misc, ...)
293{
294	struct smu_cmd *cmd = &scmd->cmd;
295	va_list list;
296	int i;
297
298	if (data_len > sizeof(scmd->buffer))
299		return -EINVAL;
300
301	memset(scmd, 0, sizeof(*scmd));
302	cmd->cmd = command;
303	cmd->data_len = data_len;
304	cmd->data_buf = scmd->buffer;
305	cmd->reply_len = sizeof(scmd->buffer);
306	cmd->reply_buf = scmd->buffer;
307	cmd->done = done;
308	cmd->misc = misc;
309
310	va_start(list, misc);
311	for (i = 0; i < data_len; ++i)
312		scmd->buffer[i] = (u8)va_arg(list, int);
313	va_end(list);
314
315	return smu_queue_cmd(cmd);
316}
317EXPORT_SYMBOL(smu_queue_simple);
318
319
320void smu_poll(void)
321{
322	u8 gpio;
323
324	if (smu == NULL)
325		return;
326
327	gpio = pmac_do_feature_call(PMAC_FTR_READ_GPIO, NULL, smu->doorbell);
328	if ((gpio & 7) == 7)
329		smu_db_intr(smu->db_irq, smu);
330}
331EXPORT_SYMBOL(smu_poll);
332
333
334void smu_done_complete(struct smu_cmd *cmd, void *misc)
335{
336	struct completion *comp = misc;
337
338	complete(comp);
339}
340EXPORT_SYMBOL(smu_done_complete);
341
342
343void smu_spinwait_cmd(struct smu_cmd *cmd)
344{
345	while(cmd->status == 1)
346		smu_poll();
347}
348EXPORT_SYMBOL(smu_spinwait_cmd);
349
350
351/* RTC low level commands */
352static inline int bcd2hex (int n)
353{
354	return (((n & 0xf0) >> 4) * 10) + (n & 0xf);
355}
356
357
358static inline int hex2bcd (int n)
359{
360	return ((n / 10) << 4) + (n % 10);
361}
362
363
364static inline void smu_fill_set_rtc_cmd(struct smu_cmd_buf *cmd_buf,
365					struct rtc_time *time)
366{
367	cmd_buf->cmd = 0x8e;
368	cmd_buf->length = 8;
369	cmd_buf->data[0] = 0x80;
370	cmd_buf->data[1] = hex2bcd(time->tm_sec);
371	cmd_buf->data[2] = hex2bcd(time->tm_min);
372	cmd_buf->data[3] = hex2bcd(time->tm_hour);
373	cmd_buf->data[4] = time->tm_wday;
374	cmd_buf->data[5] = hex2bcd(time->tm_mday);
375	cmd_buf->data[6] = hex2bcd(time->tm_mon) + 1;
376	cmd_buf->data[7] = hex2bcd(time->tm_year - 100);
377}
378
379
380int smu_get_rtc_time(struct rtc_time *time, int spinwait)
381{
382	struct smu_simple_cmd cmd;
383	int rc;
384
385	if (smu == NULL)
386		return -ENODEV;
387
388	memset(time, 0, sizeof(struct rtc_time));
389	rc = smu_queue_simple(&cmd, SMU_CMD_RTC_COMMAND, 1, NULL, NULL,
390			      SMU_CMD_RTC_GET_DATETIME);
391	if (rc)
392		return rc;
393	smu_spinwait_simple(&cmd);
394
395	time->tm_sec = bcd2hex(cmd.buffer[0]);
396	time->tm_min = bcd2hex(cmd.buffer[1]);
397	time->tm_hour = bcd2hex(cmd.buffer[2]);
398	time->tm_wday = bcd2hex(cmd.buffer[3]);
399	time->tm_mday = bcd2hex(cmd.buffer[4]);
400	time->tm_mon = bcd2hex(cmd.buffer[5]) - 1;
401	time->tm_year = bcd2hex(cmd.buffer[6]) + 100;
402
403	return 0;
404}
405
406
407int smu_set_rtc_time(struct rtc_time *time, int spinwait)
408{
409	struct smu_simple_cmd cmd;
410	int rc;
411
412	if (smu == NULL)
413		return -ENODEV;
414
415	rc = smu_queue_simple(&cmd, SMU_CMD_RTC_COMMAND, 8, NULL, NULL,
416			      SMU_CMD_RTC_SET_DATETIME,
417			      hex2bcd(time->tm_sec),
418			      hex2bcd(time->tm_min),
419			      hex2bcd(time->tm_hour),
420			      time->tm_wday,
421			      hex2bcd(time->tm_mday),
422			      hex2bcd(time->tm_mon) + 1,
423			      hex2bcd(time->tm_year - 100));
424	if (rc)
425		return rc;
426	smu_spinwait_simple(&cmd);
427
428	return 0;
429}
430
431
432void smu_shutdown(void)
433{
434	struct smu_simple_cmd cmd;
435
436	if (smu == NULL)
437		return;
438
439	if (smu_queue_simple(&cmd, SMU_CMD_POWER_COMMAND, 9, NULL, NULL,
440			     'S', 'H', 'U', 'T', 'D', 'O', 'W', 'N', 0))
441		return;
442	smu_spinwait_simple(&cmd);
443	for (;;)
444		;
445}
446
447
448void smu_restart(void)
449{
450	struct smu_simple_cmd cmd;
451
452	if (smu == NULL)
453		return;
454
455	if (smu_queue_simple(&cmd, SMU_CMD_POWER_COMMAND, 8, NULL, NULL,
456			     'R', 'E', 'S', 'T', 'A', 'R', 'T', 0))
457		return;
458	smu_spinwait_simple(&cmd);
459	for (;;)
460		;
461}
462
463
464int smu_present(void)
465{
466	return smu != NULL;
467}
468EXPORT_SYMBOL(smu_present);
469
470
471int __init smu_init (void)
472{
473	struct device_node *np;
474	const u32 *data;
475	int ret = 0;
476
477        np = of_find_node_by_type(NULL, "smu");
478        if (np == NULL)
479		return -ENODEV;
480
481	printk(KERN_INFO "SMU: Driver %s %s\n", VERSION, AUTHOR);
482
483	/*
484	 * SMU based G5s need some memory below 2Gb. Thankfully this is
485	 * called at a time where memblock is still available.
486	 */
487	smu_cmdbuf_abs = memblock_phys_alloc_range(4096, 4096, 0, 0x80000000UL);
488	if (smu_cmdbuf_abs == 0) {
489		printk(KERN_ERR "SMU: Command buffer allocation failed !\n");
490		ret = -EINVAL;
491		goto fail_np;
492	}
493
494	smu = memblock_alloc(sizeof(struct smu_device), SMP_CACHE_BYTES);
495	if (!smu)
496		panic("%s: Failed to allocate %zu bytes\n", __func__,
497		      sizeof(struct smu_device));
498
499	spin_lock_init(&smu->lock);
500	INIT_LIST_HEAD(&smu->cmd_list);
501	INIT_LIST_HEAD(&smu->cmd_i2c_list);
502	smu->of_node = np;
503	smu->db_irq = 0;
504	smu->msg_irq = 0;
505
506	/* smu_cmdbuf_abs is in the low 2G of RAM, can be converted to a
507	 * 32 bits value safely
508	 */
509	smu->cmd_buf_abs = (u32)smu_cmdbuf_abs;
510	smu->cmd_buf = __va(smu_cmdbuf_abs);
511
512	smu->db_node = of_find_node_by_name(NULL, "smu-doorbell");
513	if (smu->db_node == NULL) {
514		printk(KERN_ERR "SMU: Can't find doorbell GPIO !\n");
515		ret = -ENXIO;
516		goto fail_bootmem;
517	}
518	data = of_get_property(smu->db_node, "reg", NULL);
519	if (data == NULL) {
520		printk(KERN_ERR "SMU: Can't find doorbell GPIO address !\n");
521		ret = -ENXIO;
522		goto fail_db_node;
523	}
524
525	/* Current setup has one doorbell GPIO that does both doorbell
526	 * and ack. GPIOs are at 0x50, best would be to find that out
527	 * in the device-tree though.
528	 */
529	smu->doorbell = *data;
530	if (smu->doorbell < 0x50)
531		smu->doorbell += 0x50;
532
533	/* Now look for the smu-interrupt GPIO */
534	do {
535		smu->msg_node = of_find_node_by_name(NULL, "smu-interrupt");
536		if (smu->msg_node == NULL)
537			break;
538		data = of_get_property(smu->msg_node, "reg", NULL);
539		if (data == NULL) {
540			of_node_put(smu->msg_node);
541			smu->msg_node = NULL;
542			break;
543		}
544		smu->msg = *data;
545		if (smu->msg < 0x50)
546			smu->msg += 0x50;
547	} while(0);
548
549	/* Doorbell buffer is currently hard-coded, I didn't find a proper
550	 * device-tree entry giving the address. Best would probably to use
551	 * an offset for K2 base though, but let's do it that way for now.
552	 */
553	smu->db_buf = ioremap(0x8000860c, 0x1000);
554	if (smu->db_buf == NULL) {
555		printk(KERN_ERR "SMU: Can't map doorbell buffer pointer !\n");
556		ret = -ENXIO;
557		goto fail_msg_node;
558	}
559
560	/* U3 has an issue with NAP mode when issuing SMU commands */
561	smu->broken_nap = pmac_get_uninorth_variant() < 4;
562	if (smu->broken_nap)
563		printk(KERN_INFO "SMU: using NAP mode workaround\n");
564
565	sys_ctrler = SYS_CTRLER_SMU;
566	return 0;
567
568fail_msg_node:
569	of_node_put(smu->msg_node);
570fail_db_node:
571	of_node_put(smu->db_node);
572fail_bootmem:
573	memblock_free(__pa(smu), sizeof(struct smu_device));
574	smu = NULL;
575fail_np:
576	of_node_put(np);
577	return ret;
578}
579
580
581static int smu_late_init(void)
582{
583	if (!smu)
584		return 0;
585
586	timer_setup(&smu->i2c_timer, smu_i2c_retry, 0);
587
588	if (smu->db_node) {
589		smu->db_irq = irq_of_parse_and_map(smu->db_node, 0);
590		if (!smu->db_irq)
591			printk(KERN_ERR "smu: failed to map irq for node %pOF\n",
592			       smu->db_node);
593	}
594	if (smu->msg_node) {
595		smu->msg_irq = irq_of_parse_and_map(smu->msg_node, 0);
596		if (!smu->msg_irq)
597			printk(KERN_ERR "smu: failed to map irq for node %pOF\n",
598			       smu->msg_node);
599	}
600
601	/*
602	 * Try to request the interrupts
603	 */
604
605	if (smu->db_irq) {
606		if (request_irq(smu->db_irq, smu_db_intr,
607				IRQF_SHARED, "SMU doorbell", smu) < 0) {
608			printk(KERN_WARNING "SMU: can't "
609			       "request interrupt %d\n",
610			       smu->db_irq);
611			smu->db_irq = 0;
612		}
613	}
614
615	if (smu->msg_irq) {
616		if (request_irq(smu->msg_irq, smu_msg_intr,
617				IRQF_SHARED, "SMU message", smu) < 0) {
618			printk(KERN_WARNING "SMU: can't "
619			       "request interrupt %d\n",
620			       smu->msg_irq);
621			smu->msg_irq = 0;
622		}
623	}
624
625	smu_irq_inited = 1;
626	return 0;
627}
628/* This has to be before arch_initcall as the low i2c stuff relies on the
629 * above having been done before we reach arch_initcalls
630 */
631core_initcall(smu_late_init);
632
633/*
634 * sysfs visibility
635 */
636
637static void smu_expose_childs(struct work_struct *unused)
638{
639	struct device_node *np;
640
641	for_each_child_of_node(smu->of_node, np)
642		if (of_device_is_compatible(np, "smu-sensors"))
643			of_platform_device_create(np, "smu-sensors",
644						  &smu->of_dev->dev);
645}
646
647static DECLARE_WORK(smu_expose_childs_work, smu_expose_childs);
648
649static int smu_platform_probe(struct platform_device* dev)
650{
651	if (!smu)
652		return -ENODEV;
653	smu->of_dev = dev;
654
655	/*
656	 * Ok, we are matched, now expose all i2c busses. We have to defer
657	 * that unfortunately or it would deadlock inside the device model
658	 */
659	schedule_work(&smu_expose_childs_work);
660
661	return 0;
662}
663
664static const struct of_device_id smu_platform_match[] =
665{
666	{
667		.type		= "smu",
668	},
669	{},
670};
671
672static struct platform_driver smu_of_platform_driver =
673{
674	.driver = {
675		.name = "smu",
676		.of_match_table = smu_platform_match,
677	},
678	.probe		= smu_platform_probe,
679};
680
681static int __init smu_init_sysfs(void)
682{
683	/*
684	 * For now, we don't power manage machines with an SMU chip,
685	 * I'm a bit too far from figuring out how that works with those
686	 * new chipsets, but that will come back and bite us
687	 */
688	platform_driver_register(&smu_of_platform_driver);
689	return 0;
690}
691
692device_initcall(smu_init_sysfs);
693
694struct platform_device *smu_get_ofdev(void)
695{
696	if (!smu)
697		return NULL;
698	return smu->of_dev;
699}
700
701EXPORT_SYMBOL_GPL(smu_get_ofdev);
702
703/*
704 * i2c interface
705 */
706
707static void smu_i2c_complete_command(struct smu_i2c_cmd *cmd, int fail)
708{
709	void (*done)(struct smu_i2c_cmd *cmd, void *misc) = cmd->done;
710	void *misc = cmd->misc;
711	unsigned long flags;
712
713	/* Check for read case */
714	if (!fail && cmd->read) {
715		if (cmd->pdata[0] < 1)
716			fail = 1;
717		else
718			memcpy(cmd->info.data, &cmd->pdata[1],
719			       cmd->info.datalen);
720	}
721
722	DPRINTK("SMU: completing, success: %d\n", !fail);
723
724	/* Update status and mark no pending i2c command with lock
725	 * held so nobody comes in while we dequeue an eventual
726	 * pending next i2c command
727	 */
728	spin_lock_irqsave(&smu->lock, flags);
729	smu->cmd_i2c_cur = NULL;
730	wmb();
731	cmd->status = fail ? -EIO : 0;
732
733	/* Is there another i2c command waiting ? */
734	if (!list_empty(&smu->cmd_i2c_list)) {
735		struct smu_i2c_cmd *newcmd;
736
737		/* Fetch it, new current, remove from list */
738		newcmd = list_entry(smu->cmd_i2c_list.next,
739				    struct smu_i2c_cmd, link);
740		smu->cmd_i2c_cur = newcmd;
741		list_del(&cmd->link);
742
743		/* Queue with low level smu */
744		list_add_tail(&cmd->scmd.link, &smu->cmd_list);
745		if (smu->cmd_cur == NULL)
746			smu_start_cmd();
747	}
748	spin_unlock_irqrestore(&smu->lock, flags);
749
750	/* Call command completion handler if any */
751	if (done)
752		done(cmd, misc);
753
754}
755
756
757static void smu_i2c_retry(struct timer_list *unused)
758{
759	struct smu_i2c_cmd	*cmd = smu->cmd_i2c_cur;
760
761	DPRINTK("SMU: i2c failure, requeuing...\n");
762
763	/* requeue command simply by resetting reply_len */
764	cmd->pdata[0] = 0xff;
765	cmd->scmd.reply_len = sizeof(cmd->pdata);
766	smu_queue_cmd(&cmd->scmd);
767}
768
769
770static void smu_i2c_low_completion(struct smu_cmd *scmd, void *misc)
771{
772	struct smu_i2c_cmd	*cmd = misc;
773	int			fail = 0;
774
775	DPRINTK("SMU: i2c compl. stage=%d status=%x pdata[0]=%x rlen: %x\n",
776		cmd->stage, scmd->status, cmd->pdata[0], scmd->reply_len);
777
778	/* Check for possible status */
779	if (scmd->status < 0)
780		fail = 1;
781	else if (cmd->read) {
782		if (cmd->stage == 0)
783			fail = cmd->pdata[0] != 0;
784		else
785			fail = cmd->pdata[0] >= 0x80;
786	} else {
787		fail = cmd->pdata[0] != 0;
788	}
789
790	/* Handle failures by requeuing command, after 5ms interval
791	 */
792	if (fail && --cmd->retries > 0) {
793		DPRINTK("SMU: i2c failure, starting timer...\n");
794		BUG_ON(cmd != smu->cmd_i2c_cur);
795		if (!smu_irq_inited) {
796			mdelay(5);
797			smu_i2c_retry(NULL);
798			return;
799		}
800		mod_timer(&smu->i2c_timer, jiffies + msecs_to_jiffies(5));
801		return;
802	}
803
804	/* If failure or stage 1, command is complete */
805	if (fail || cmd->stage != 0) {
806		smu_i2c_complete_command(cmd, fail);
807		return;
808	}
809
810	DPRINTK("SMU: going to stage 1\n");
811
812	/* Ok, initial command complete, now poll status */
813	scmd->reply_buf = cmd->pdata;
814	scmd->reply_len = sizeof(cmd->pdata);
815	scmd->data_buf = cmd->pdata;
816	scmd->data_len = 1;
817	cmd->pdata[0] = 0;
818	cmd->stage = 1;
819	cmd->retries = 20;
820	smu_queue_cmd(scmd);
821}
822
823
824int smu_queue_i2c(struct smu_i2c_cmd *cmd)
825{
826	unsigned long flags;
827
828	if (smu == NULL)
829		return -ENODEV;
830
831	/* Fill most fields of scmd */
832	cmd->scmd.cmd = SMU_CMD_I2C_COMMAND;
833	cmd->scmd.done = smu_i2c_low_completion;
834	cmd->scmd.misc = cmd;
835	cmd->scmd.reply_buf = cmd->pdata;
836	cmd->scmd.reply_len = sizeof(cmd->pdata);
837	cmd->scmd.data_buf = (u8 *)(char *)&cmd->info;
838	cmd->scmd.status = 1;
839	cmd->stage = 0;
840	cmd->pdata[0] = 0xff;
841	cmd->retries = 20;
842	cmd->status = 1;
843
844	/* Check transfer type, sanitize some "info" fields
845	 * based on transfer type and do more checking
846	 */
847	cmd->info.caddr = cmd->info.devaddr;
848	cmd->read = cmd->info.devaddr & 0x01;
849	switch(cmd->info.type) {
850	case SMU_I2C_TRANSFER_SIMPLE:
851		memset(&cmd->info.sublen, 0, 4);
852		break;
853	case SMU_I2C_TRANSFER_COMBINED:
854		cmd->info.devaddr &= 0xfe;
855		fallthrough;
856	case SMU_I2C_TRANSFER_STDSUB:
857		if (cmd->info.sublen > 3)
858			return -EINVAL;
859		break;
860	default:
861		return -EINVAL;
862	}
863
864	/* Finish setting up command based on transfer direction
865	 */
866	if (cmd->read) {
867		if (cmd->info.datalen > SMU_I2C_READ_MAX)
868			return -EINVAL;
869		memset(cmd->info.data, 0xff, cmd->info.datalen);
870		cmd->scmd.data_len = 9;
871	} else {
872		if (cmd->info.datalen > SMU_I2C_WRITE_MAX)
873			return -EINVAL;
874		cmd->scmd.data_len = 9 + cmd->info.datalen;
875	}
876
877	DPRINTK("SMU: i2c enqueuing command\n");
878	DPRINTK("SMU:   %s, len=%d bus=%x addr=%x sub0=%x type=%x\n",
879		cmd->read ? "read" : "write", cmd->info.datalen,
880		cmd->info.bus, cmd->info.caddr,
881		cmd->info.subaddr[0], cmd->info.type);
882
883
884	/* Enqueue command in i2c list, and if empty, enqueue also in
885	 * main command list
886	 */
887	spin_lock_irqsave(&smu->lock, flags);
888	if (smu->cmd_i2c_cur == NULL) {
889		smu->cmd_i2c_cur = cmd;
890		list_add_tail(&cmd->scmd.link, &smu->cmd_list);
891		if (smu->cmd_cur == NULL)
892			smu_start_cmd();
893	} else
894		list_add_tail(&cmd->link, &smu->cmd_i2c_list);
895	spin_unlock_irqrestore(&smu->lock, flags);
896
897	return 0;
898}
899
900/*
901 * Handling of "partitions"
902 */
903
904static int smu_read_datablock(u8 *dest, unsigned int addr, unsigned int len)
905{
906	DECLARE_COMPLETION_ONSTACK(comp);
907	unsigned int chunk;
908	struct smu_cmd cmd;
909	int rc;
910	u8 params[8];
911
912	/* We currently use a chunk size of 0xe. We could check the
913	 * SMU firmware version and use bigger sizes though
914	 */
915	chunk = 0xe;
916
917	while (len) {
918		unsigned int clen = min(len, chunk);
919
920		cmd.cmd = SMU_CMD_MISC_ee_COMMAND;
921		cmd.data_len = 7;
922		cmd.data_buf = params;
923		cmd.reply_len = chunk;
924		cmd.reply_buf = dest;
925		cmd.done = smu_done_complete;
926		cmd.misc = &comp;
927		params[0] = SMU_CMD_MISC_ee_GET_DATABLOCK_REC;
928		params[1] = 0x4;
929		*((u32 *)&params[2]) = addr;
930		params[6] = clen;
931
932		rc = smu_queue_cmd(&cmd);
933		if (rc)
934			return rc;
935		wait_for_completion(&comp);
936		if (cmd.status != 0)
937			return rc;
938		if (cmd.reply_len != clen) {
939			printk(KERN_DEBUG "SMU: short read in "
940			       "smu_read_datablock, got: %d, want: %d\n",
941			       cmd.reply_len, clen);
942			return -EIO;
943		}
944		len -= clen;
945		addr += clen;
946		dest += clen;
947	}
948	return 0;
949}
950
951static struct smu_sdbp_header *smu_create_sdb_partition(int id)
952{
953	DECLARE_COMPLETION_ONSTACK(comp);
954	struct smu_simple_cmd cmd;
955	unsigned int addr, len, tlen;
956	struct smu_sdbp_header *hdr;
957	struct property *prop;
958
959	/* First query the partition info */
960	DPRINTK("SMU: Query partition infos ... (irq=%d)\n", smu->db_irq);
961	smu_queue_simple(&cmd, SMU_CMD_PARTITION_COMMAND, 2,
962			 smu_done_complete, &comp,
963			 SMU_CMD_PARTITION_LATEST, id);
964	wait_for_completion(&comp);
965	DPRINTK("SMU: done, status: %d, reply_len: %d\n",
966		cmd.cmd.status, cmd.cmd.reply_len);
967
968	/* Partition doesn't exist (or other error) */
969	if (cmd.cmd.status != 0 || cmd.cmd.reply_len != 6)
970		return NULL;
971
972	/* Fetch address and length from reply */
973	addr = *((u16 *)cmd.buffer);
974	len = cmd.buffer[3] << 2;
975	/* Calucluate total length to allocate, including the 17 bytes
976	 * for "sdb-partition-XX" that we append at the end of the buffer
977	 */
978	tlen = sizeof(struct property) + len + 18;
979
980	prop = kzalloc(tlen, GFP_KERNEL);
981	if (prop == NULL)
982		return NULL;
983	hdr = (struct smu_sdbp_header *)(prop + 1);
984	prop->name = ((char *)prop) + tlen - 18;
985	sprintf(prop->name, "sdb-partition-%02x", id);
986	prop->length = len;
987	prop->value = hdr;
988	prop->next = NULL;
989
990	/* Read the datablock */
991	if (smu_read_datablock((u8 *)hdr, addr, len)) {
992		printk(KERN_DEBUG "SMU: datablock read failed while reading "
993		       "partition %02x !\n", id);
994		goto failure;
995	}
996
997	/* Got it, check a few things and create the property */
998	if (hdr->id != id) {
999		printk(KERN_DEBUG "SMU: Reading partition %02x and got "
1000		       "%02x !\n", id, hdr->id);
1001		goto failure;
1002	}
1003	if (of_add_property(smu->of_node, prop)) {
1004		printk(KERN_DEBUG "SMU: Failed creating sdb-partition-%02x "
1005		       "property !\n", id);
1006		goto failure;
1007	}
1008
1009	return hdr;
1010 failure:
1011	kfree(prop);
1012	return NULL;
1013}
1014
1015/* Note: Only allowed to return error code in pointers (using ERR_PTR)
1016 * when interruptible is 1
1017 */
1018static const struct smu_sdbp_header *__smu_get_sdb_partition(int id,
1019		unsigned int *size, int interruptible)
1020{
1021	char pname[32];
1022	const struct smu_sdbp_header *part;
1023
1024	if (!smu)
1025		return NULL;
1026
1027	sprintf(pname, "sdb-partition-%02x", id);
1028
1029	DPRINTK("smu_get_sdb_partition(%02x)\n", id);
1030
1031	if (interruptible) {
1032		int rc;
1033		rc = mutex_lock_interruptible(&smu_part_access);
1034		if (rc)
1035			return ERR_PTR(rc);
1036	} else
1037		mutex_lock(&smu_part_access);
1038
1039	part = of_get_property(smu->of_node, pname, size);
1040	if (part == NULL) {
1041		DPRINTK("trying to extract from SMU ...\n");
1042		part = smu_create_sdb_partition(id);
1043		if (part != NULL && size)
1044			*size = part->len << 2;
1045	}
1046	mutex_unlock(&smu_part_access);
1047	return part;
1048}
1049
1050const struct smu_sdbp_header *smu_get_sdb_partition(int id, unsigned int *size)
1051{
1052	return __smu_get_sdb_partition(id, size, 0);
1053}
1054EXPORT_SYMBOL(smu_get_sdb_partition);
1055
1056
1057/*
1058 * Userland driver interface
1059 */
1060
1061
1062static LIST_HEAD(smu_clist);
1063static DEFINE_SPINLOCK(smu_clist_lock);
1064
1065enum smu_file_mode {
1066	smu_file_commands,
1067	smu_file_events,
1068	smu_file_closing
1069};
1070
1071struct smu_private
1072{
1073	struct list_head	list;
1074	enum smu_file_mode	mode;
1075	int			busy;
1076	struct smu_cmd		cmd;
1077	spinlock_t		lock;
1078	wait_queue_head_t	wait;
1079	u8			buffer[SMU_MAX_DATA];
1080};
1081
1082
1083static int smu_open(struct inode *inode, struct file *file)
1084{
1085	struct smu_private *pp;
1086	unsigned long flags;
1087
1088	pp = kzalloc(sizeof(struct smu_private), GFP_KERNEL);
1089	if (pp == 0)
1090		return -ENOMEM;
1091	spin_lock_init(&pp->lock);
1092	pp->mode = smu_file_commands;
1093	init_waitqueue_head(&pp->wait);
1094
1095	mutex_lock(&smu_mutex);
1096	spin_lock_irqsave(&smu_clist_lock, flags);
1097	list_add(&pp->list, &smu_clist);
1098	spin_unlock_irqrestore(&smu_clist_lock, flags);
1099	file->private_data = pp;
1100	mutex_unlock(&smu_mutex);
1101
1102	return 0;
1103}
1104
1105
1106static void smu_user_cmd_done(struct smu_cmd *cmd, void *misc)
1107{
1108	struct smu_private *pp = misc;
1109
1110	wake_up_all(&pp->wait);
1111}
1112
1113
1114static ssize_t smu_write(struct file *file, const char __user *buf,
1115			 size_t count, loff_t *ppos)
1116{
1117	struct smu_private *pp = file->private_data;
1118	unsigned long flags;
1119	struct smu_user_cmd_hdr hdr;
1120	int rc = 0;
1121
1122	if (pp->busy)
1123		return -EBUSY;
1124	else if (copy_from_user(&hdr, buf, sizeof(hdr)))
1125		return -EFAULT;
1126	else if (hdr.cmdtype == SMU_CMDTYPE_WANTS_EVENTS) {
1127		pp->mode = smu_file_events;
1128		return 0;
1129	} else if (hdr.cmdtype == SMU_CMDTYPE_GET_PARTITION) {
1130		const struct smu_sdbp_header *part;
1131		part = __smu_get_sdb_partition(hdr.cmd, NULL, 1);
1132		if (part == NULL)
1133			return -EINVAL;
1134		else if (IS_ERR(part))
1135			return PTR_ERR(part);
1136		return 0;
1137	} else if (hdr.cmdtype != SMU_CMDTYPE_SMU)
1138		return -EINVAL;
1139	else if (pp->mode != smu_file_commands)
1140		return -EBADFD;
1141	else if (hdr.data_len > SMU_MAX_DATA)
1142		return -EINVAL;
1143
1144	spin_lock_irqsave(&pp->lock, flags);
1145	if (pp->busy) {
1146		spin_unlock_irqrestore(&pp->lock, flags);
1147		return -EBUSY;
1148	}
1149	pp->busy = 1;
1150	pp->cmd.status = 1;
1151	spin_unlock_irqrestore(&pp->lock, flags);
1152
1153	if (copy_from_user(pp->buffer, buf + sizeof(hdr), hdr.data_len)) {
1154		pp->busy = 0;
1155		return -EFAULT;
1156	}
1157
1158	pp->cmd.cmd = hdr.cmd;
1159	pp->cmd.data_len = hdr.data_len;
1160	pp->cmd.reply_len = SMU_MAX_DATA;
1161	pp->cmd.data_buf = pp->buffer;
1162	pp->cmd.reply_buf = pp->buffer;
1163	pp->cmd.done = smu_user_cmd_done;
1164	pp->cmd.misc = pp;
1165	rc = smu_queue_cmd(&pp->cmd);
1166	if (rc < 0)
1167		return rc;
1168	return count;
1169}
1170
1171
1172static ssize_t smu_read_command(struct file *file, struct smu_private *pp,
1173				char __user *buf, size_t count)
1174{
1175	DECLARE_WAITQUEUE(wait, current);
1176	struct smu_user_reply_hdr hdr;
1177	unsigned long flags;
1178	int size, rc = 0;
1179
1180	if (!pp->busy)
1181		return 0;
1182	if (count < sizeof(struct smu_user_reply_hdr))
1183		return -EOVERFLOW;
1184	spin_lock_irqsave(&pp->lock, flags);
1185	if (pp->cmd.status == 1) {
1186		if (file->f_flags & O_NONBLOCK) {
1187			spin_unlock_irqrestore(&pp->lock, flags);
1188			return -EAGAIN;
1189		}
1190		add_wait_queue(&pp->wait, &wait);
1191		for (;;) {
1192			set_current_state(TASK_INTERRUPTIBLE);
1193			rc = 0;
1194			if (pp->cmd.status != 1)
1195				break;
1196			rc = -ERESTARTSYS;
1197			if (signal_pending(current))
1198				break;
1199			spin_unlock_irqrestore(&pp->lock, flags);
1200			schedule();
1201			spin_lock_irqsave(&pp->lock, flags);
1202		}
1203		set_current_state(TASK_RUNNING);
1204		remove_wait_queue(&pp->wait, &wait);
1205	}
1206	spin_unlock_irqrestore(&pp->lock, flags);
1207	if (rc)
1208		return rc;
1209	if (pp->cmd.status != 0)
1210		pp->cmd.reply_len = 0;
1211	size = sizeof(hdr) + pp->cmd.reply_len;
1212	if (count < size)
1213		size = count;
1214	rc = size;
1215	hdr.status = pp->cmd.status;
1216	hdr.reply_len = pp->cmd.reply_len;
1217	if (copy_to_user(buf, &hdr, sizeof(hdr)))
1218		return -EFAULT;
1219	size -= sizeof(hdr);
1220	if (size && copy_to_user(buf + sizeof(hdr), pp->buffer, size))
1221		return -EFAULT;
1222	pp->busy = 0;
1223
1224	return rc;
1225}
1226
1227
1228static ssize_t smu_read_events(struct file *file, struct smu_private *pp,
1229			       char __user *buf, size_t count)
1230{
1231	/* Not implemented */
1232	msleep_interruptible(1000);
1233	return 0;
1234}
1235
1236
1237static ssize_t smu_read(struct file *file, char __user *buf,
1238			size_t count, loff_t *ppos)
1239{
1240	struct smu_private *pp = file->private_data;
1241
1242	if (pp->mode == smu_file_commands)
1243		return smu_read_command(file, pp, buf, count);
1244	if (pp->mode == smu_file_events)
1245		return smu_read_events(file, pp, buf, count);
1246
1247	return -EBADFD;
1248}
1249
1250static __poll_t smu_fpoll(struct file *file, poll_table *wait)
1251{
1252	struct smu_private *pp = file->private_data;
1253	__poll_t mask = 0;
1254	unsigned long flags;
1255
1256	if (pp == 0)
1257		return 0;
1258
1259	if (pp->mode == smu_file_commands) {
1260		poll_wait(file, &pp->wait, wait);
1261
1262		spin_lock_irqsave(&pp->lock, flags);
1263		if (pp->busy && pp->cmd.status != 1)
1264			mask |= EPOLLIN;
1265		spin_unlock_irqrestore(&pp->lock, flags);
1266	}
1267	if (pp->mode == smu_file_events) {
1268		/* Not yet implemented */
1269	}
1270	return mask;
1271}
1272
1273static int smu_release(struct inode *inode, struct file *file)
1274{
1275	struct smu_private *pp = file->private_data;
1276	unsigned long flags;
1277	unsigned int busy;
1278
1279	if (pp == 0)
1280		return 0;
1281
1282	file->private_data = NULL;
1283
1284	/* Mark file as closing to avoid races with new request */
1285	spin_lock_irqsave(&pp->lock, flags);
1286	pp->mode = smu_file_closing;
1287	busy = pp->busy;
1288
1289	/* Wait for any pending request to complete */
1290	if (busy && pp->cmd.status == 1) {
1291		DECLARE_WAITQUEUE(wait, current);
1292
1293		add_wait_queue(&pp->wait, &wait);
1294		for (;;) {
1295			set_current_state(TASK_UNINTERRUPTIBLE);
1296			if (pp->cmd.status != 1)
1297				break;
1298			spin_unlock_irqrestore(&pp->lock, flags);
1299			schedule();
1300			spin_lock_irqsave(&pp->lock, flags);
1301		}
1302		set_current_state(TASK_RUNNING);
1303		remove_wait_queue(&pp->wait, &wait);
1304	}
1305	spin_unlock_irqrestore(&pp->lock, flags);
1306
1307	spin_lock_irqsave(&smu_clist_lock, flags);
1308	list_del(&pp->list);
1309	spin_unlock_irqrestore(&smu_clist_lock, flags);
1310	kfree(pp);
1311
1312	return 0;
1313}
1314
1315
1316static const struct file_operations smu_device_fops = {
1317	.llseek		= no_llseek,
1318	.read		= smu_read,
1319	.write		= smu_write,
1320	.poll		= smu_fpoll,
1321	.open		= smu_open,
1322	.release	= smu_release,
1323};
1324
1325static struct miscdevice pmu_device = {
1326	MISC_DYNAMIC_MINOR, "smu", &smu_device_fops
1327};
1328
1329static int smu_device_init(void)
1330{
1331	if (!smu)
1332		return -ENODEV;
1333	if (misc_register(&pmu_device) < 0)
1334		printk(KERN_ERR "via-pmu: cannot register misc device.\n");
1335	return 0;
1336}
1337device_initcall(smu_device_init);
1338