xref: /openbmc/linux/drivers/sbus/char/envctrl.c (revision 9bd5910d)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* envctrl.c: Temperature and Fan monitoring on Machines providing it.
3  *
4  * Copyright (C) 1998  Eddie C. Dost  (ecd@skynet.be)
5  * Copyright (C) 2000  Vinh Truong    (vinh.truong@eng.sun.com)
6  * VT - The implementation is to support Sun Microelectronics (SME) platform
7  *      environment monitoring.  SME platforms use pcf8584 as the i2c bus
8  *      controller to access pcf8591 (8-bit A/D and D/A converter) and
9  *      pcf8571 (256 x 8-bit static low-voltage RAM with I2C-bus interface).
10  *      At board level, it follows SME Firmware I2C Specification. Reference:
11  * 	http://www-eu2.semiconductors.com/pip/PCF8584P
12  * 	http://www-eu2.semiconductors.com/pip/PCF8574AP
13  * 	http://www-eu2.semiconductors.com/pip/PCF8591P
14  *
15  * EB - Added support for CP1500 Global Address and PS/Voltage monitoring.
16  * 		Eric Brower <ebrower@usa.net>
17  *
18  * DB - Audit every copy_to_user in envctrl_read.
19  *              Daniele Bellucci <bellucda@tiscali.it>
20  */
21 
22 #include <linux/module.h>
23 #include <linux/kthread.h>
24 #include <linux/delay.h>
25 #include <linux/ioport.h>
26 #include <linux/miscdevice.h>
27 #include <linux/kmod.h>
28 #include <linux/reboot.h>
29 #include <linux/slab.h>
30 #include <linux/of.h>
31 #include <linux/of_device.h>
32 
33 #include <linux/uaccess.h>
34 #include <asm/envctrl.h>
35 #include <asm/io.h>
36 
37 #define DRIVER_NAME	"envctrl"
38 #define PFX		DRIVER_NAME ": "
39 
40 #define ENVCTRL_MINOR	162
41 
42 #define PCF8584_ADDRESS	0x55
43 
44 #define CONTROL_PIN	0x80
45 #define CONTROL_ES0	0x40
46 #define CONTROL_ES1	0x20
47 #define CONTROL_ES2	0x10
48 #define CONTROL_ENI	0x08
49 #define CONTROL_STA	0x04
50 #define CONTROL_STO	0x02
51 #define CONTROL_ACK	0x01
52 
53 #define STATUS_PIN	0x80
54 #define STATUS_STS	0x20
55 #define STATUS_BER	0x10
56 #define STATUS_LRB	0x08
57 #define STATUS_AD0	0x08
58 #define STATUS_AAB	0x04
59 #define STATUS_LAB	0x02
60 #define STATUS_BB	0x01
61 
62 /*
63  * CLK Mode Register.
64  */
65 #define BUS_CLK_90	0x00
66 #define BUS_CLK_45	0x01
67 #define BUS_CLK_11	0x02
68 #define BUS_CLK_1_5	0x03
69 
70 #define CLK_3		0x00
71 #define CLK_4_43	0x10
72 #define CLK_6		0x14
73 #define CLK_8		0x18
74 #define CLK_12		0x1c
75 
76 #define OBD_SEND_START	0xc5    /* value to generate I2c_bus START condition */
77 #define OBD_SEND_STOP 	0xc3    /* value to generate I2c_bus STOP condition */
78 
79 /* Monitor type of i2c child device.
80  * Firmware definitions.
81  */
82 #define PCF8584_MAX_CHANNELS            8
83 #define PCF8584_GLOBALADDR_TYPE			6  /* global address monitor */
84 #define PCF8584_FANSTAT_TYPE            3  /* fan status monitor */
85 #define PCF8584_VOLTAGE_TYPE            2  /* voltage monitor    */
86 #define PCF8584_TEMP_TYPE	        	1  /* temperature monitor*/
87 
88 /* Monitor type of i2c child device.
89  * Driver definitions.
90  */
91 #define ENVCTRL_NOMON				0
92 #define ENVCTRL_CPUTEMP_MON			1    /* cpu temperature monitor */
93 #define ENVCTRL_CPUVOLTAGE_MON	  	2    /* voltage monitor         */
94 #define ENVCTRL_FANSTAT_MON  		3    /* fan status monitor      */
95 #define ENVCTRL_ETHERTEMP_MON		4    /* ethernet temperature */
96 					     /* monitor                     */
97 #define ENVCTRL_VOLTAGESTAT_MON	  	5    /* voltage status monitor  */
98 #define ENVCTRL_MTHRBDTEMP_MON		6    /* motherboard temperature */
99 #define ENVCTRL_SCSITEMP_MON		7    /* scsi temperature */
100 #define ENVCTRL_GLOBALADDR_MON		8    /* global address */
101 
102 /* Child device type.
103  * Driver definitions.
104  */
105 #define I2C_ADC				0    /* pcf8591 */
106 #define I2C_GPIO			1    /* pcf8571 */
107 
108 /* Data read from child device may need to decode
109  * through a data table and a scale.
110  * Translation type as defined by firmware.
111  */
112 #define ENVCTRL_TRANSLATE_NO		0
113 #define ENVCTRL_TRANSLATE_PARTIAL	1
114 #define ENVCTRL_TRANSLATE_COMBINED	2
115 #define ENVCTRL_TRANSLATE_FULL		3     /* table[data] */
116 #define ENVCTRL_TRANSLATE_SCALE		4     /* table[data]/scale */
117 
118 /* Driver miscellaneous definitions. */
119 #define ENVCTRL_MAX_CPU			4
120 #define CHANNEL_DESC_SZ			256
121 
122 /* Mask values for combined GlobalAddress/PowerStatus node */
123 #define ENVCTRL_GLOBALADDR_ADDR_MASK 	0x1F
124 #define ENVCTRL_GLOBALADDR_PSTAT_MASK	0x60
125 
126 /* Node 0x70 ignored on CompactPCI CP1400/1500 platforms
127  * (see envctrl_init_i2c_child)
128  */
129 #define ENVCTRL_CPCI_IGNORED_NODE		0x70
130 
131 #define PCF8584_DATA	0x00
132 #define PCF8584_CSR	0x01
133 
134 /* Each child device can be monitored by up to PCF8584_MAX_CHANNELS.
135  * Property of a port or channel as defined by the firmware.
136  */
137 struct pcf8584_channel {
138         unsigned char chnl_no;
139         unsigned char io_direction;
140         unsigned char type;
141         unsigned char last;
142 };
143 
144 /* Each child device may have one or more tables of bytes to help decode
145  * data. Table property as defined by the firmware.
146  */
147 struct pcf8584_tblprop {
148         unsigned int type;
149         unsigned int scale;
150         unsigned int offset; /* offset from the beginning of the table */
151         unsigned int size;
152 };
153 
154 /* i2c child */
155 struct i2c_child_t {
156 	/* Either ADC or GPIO. */
157 	unsigned char i2ctype;
158         unsigned long addr;
159         struct pcf8584_channel chnl_array[PCF8584_MAX_CHANNELS];
160 
161 	/* Channel info. */
162 	unsigned int total_chnls;	/* Number of monitor channels. */
163 	unsigned char fan_mask;		/* Byte mask for fan status channels. */
164 	unsigned char voltage_mask;	/* Byte mask for voltage status channels. */
165         struct pcf8584_tblprop tblprop_array[PCF8584_MAX_CHANNELS];
166 
167 	/* Properties of all monitor channels. */
168 	unsigned int total_tbls;	/* Number of monitor tables. */
169         char *tables;			/* Pointer to table(s). */
170 	char chnls_desc[CHANNEL_DESC_SZ]; /* Channel description. */
171 	char mon_type[PCF8584_MAX_CHANNELS];
172 };
173 
174 static void __iomem *i2c;
175 static struct i2c_child_t i2c_childlist[ENVCTRL_MAX_CPU*2];
176 static unsigned char chnls_mask[] = { 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80 };
177 static unsigned int warning_temperature = 0;
178 static unsigned int shutdown_temperature = 0;
179 static char read_cpu;
180 
181 /* Forward declarations. */
182 static struct i2c_child_t *envctrl_get_i2c_child(unsigned char);
183 
184 /* Function Description: Test the PIN bit (Pending Interrupt Not)
185  * 			 to test when serial transmission is completed .
186  * Return : None.
187  */
188 static void envtrl_i2c_test_pin(void)
189 {
190 	int limit = 1000000;
191 
192 	while (--limit > 0) {
193 		if (!(readb(i2c + PCF8584_CSR) & STATUS_PIN))
194 			break;
195 		udelay(1);
196 	}
197 
198 	if (limit <= 0)
199 		printk(KERN_INFO PFX "Pin status will not clear.\n");
200 }
201 
202 /* Function Description: Test busy bit.
203  * Return : None.
204  */
205 static void envctrl_i2c_test_bb(void)
206 {
207 	int limit = 1000000;
208 
209 	while (--limit > 0) {
210 		/* Busy bit 0 means busy. */
211 		if (readb(i2c + PCF8584_CSR) & STATUS_BB)
212 			break;
213 		udelay(1);
214 	}
215 
216 	if (limit <= 0)
217 		printk(KERN_INFO PFX "Busy bit will not clear.\n");
218 }
219 
220 /* Function Description: Send the address for a read access.
221  * Return : 0 if not acknowledged, otherwise acknowledged.
222  */
223 static int envctrl_i2c_read_addr(unsigned char addr)
224 {
225 	envctrl_i2c_test_bb();
226 
227 	/* Load address. */
228 	writeb(addr + 1, i2c + PCF8584_DATA);
229 
230 	envctrl_i2c_test_bb();
231 
232 	writeb(OBD_SEND_START, i2c + PCF8584_CSR);
233 
234 	/* Wait for PIN. */
235 	envtrl_i2c_test_pin();
236 
237 	/* CSR 0 means acknowledged. */
238 	if (!(readb(i2c + PCF8584_CSR) & STATUS_LRB)) {
239 		return readb(i2c + PCF8584_DATA);
240 	} else {
241 		writeb(OBD_SEND_STOP, i2c + PCF8584_CSR);
242 		return 0;
243 	}
244 }
245 
246 /* Function Description: Send the address for write mode.
247  * Return : None.
248  */
249 static void envctrl_i2c_write_addr(unsigned char addr)
250 {
251 	envctrl_i2c_test_bb();
252 	writeb(addr, i2c + PCF8584_DATA);
253 
254 	/* Generate Start condition. */
255 	writeb(OBD_SEND_START, i2c + PCF8584_CSR);
256 }
257 
258 /* Function Description: Read 1 byte of data from addr
259  *			 set by envctrl_i2c_read_addr()
260  * Return : Data from address set by envctrl_i2c_read_addr().
261  */
262 static unsigned char envctrl_i2c_read_data(void)
263 {
264 	envtrl_i2c_test_pin();
265 	writeb(CONTROL_ES0, i2c + PCF8584_CSR);  /* Send neg ack. */
266 	return readb(i2c + PCF8584_DATA);
267 }
268 
269 /* Function Description: Instruct the device which port to read data from.
270  * Return : None.
271  */
272 static void envctrl_i2c_write_data(unsigned char port)
273 {
274 	envtrl_i2c_test_pin();
275 	writeb(port, i2c + PCF8584_DATA);
276 }
277 
278 /* Function Description: Generate Stop condition after last byte is sent.
279  * Return : None.
280  */
281 static void envctrl_i2c_stop(void)
282 {
283 	envtrl_i2c_test_pin();
284 	writeb(OBD_SEND_STOP, i2c + PCF8584_CSR);
285 }
286 
287 /* Function Description: Read adc device.
288  * Return : Data at address and port.
289  */
290 static unsigned char envctrl_i2c_read_8591(unsigned char addr, unsigned char port)
291 {
292 	/* Send address. */
293 	envctrl_i2c_write_addr(addr);
294 
295 	/* Setup port to read. */
296 	envctrl_i2c_write_data(port);
297 	envctrl_i2c_stop();
298 
299 	/* Read port. */
300 	envctrl_i2c_read_addr(addr);
301 
302 	/* Do a single byte read and send stop. */
303 	envctrl_i2c_read_data();
304 	envctrl_i2c_stop();
305 
306 	return readb(i2c + PCF8584_DATA);
307 }
308 
309 /* Function Description: Read gpio device.
310  * Return : Data at address.
311  */
312 static unsigned char envctrl_i2c_read_8574(unsigned char addr)
313 {
314 	unsigned char rd;
315 
316 	envctrl_i2c_read_addr(addr);
317 
318 	/* Do a single byte read and send stop. */
319 	rd = envctrl_i2c_read_data();
320 	envctrl_i2c_stop();
321 	return rd;
322 }
323 
324 /* Function Description: Decode data read from an adc device using firmware
325  *                       table.
326  * Return: Number of read bytes. Data is stored in bufdata in ascii format.
327  */
328 static int envctrl_i2c_data_translate(unsigned char data, int translate_type,
329 				      int scale, char *tbl, char *bufdata)
330 {
331 	int len = 0;
332 
333 	switch (translate_type) {
334 	case ENVCTRL_TRANSLATE_NO:
335 		/* No decode necessary. */
336 		len = 1;
337 		bufdata[0] = data;
338 		break;
339 
340 	case ENVCTRL_TRANSLATE_FULL:
341 		/* Decode this way: data = table[data]. */
342 		len = 1;
343 		bufdata[0] = tbl[data];
344 		break;
345 
346 	case ENVCTRL_TRANSLATE_SCALE:
347 		/* Decode this way: data = table[data]/scale */
348 		sprintf(bufdata,"%d ", (tbl[data] * 10) / (scale));
349 		len = strlen(bufdata);
350 		bufdata[len - 1] = bufdata[len - 2];
351 		bufdata[len - 2] = '.';
352 		break;
353 
354 	default:
355 		break;
356 	}
357 
358 	return len;
359 }
360 
361 /* Function Description: Read cpu-related data such as cpu temperature, voltage.
362  * Return: Number of read bytes. Data is stored in bufdata in ascii format.
363  */
364 static int envctrl_read_cpu_info(int cpu, struct i2c_child_t *pchild,
365 				 char mon_type, unsigned char *bufdata)
366 {
367 	unsigned char data;
368 	int i;
369 	char *tbl, j = -1;
370 
371 	/* Find the right monitor type and channel. */
372 	for (i = 0; i < PCF8584_MAX_CHANNELS; i++) {
373 		if (pchild->mon_type[i] == mon_type) {
374 			if (++j == cpu) {
375 				break;
376 			}
377 		}
378 	}
379 
380 	if (j != cpu)
381 		return 0;
382 
383         /* Read data from address and port. */
384 	data = envctrl_i2c_read_8591((unsigned char)pchild->addr,
385 				     (unsigned char)pchild->chnl_array[i].chnl_no);
386 
387 	/* Find decoding table. */
388 	tbl = pchild->tables + pchild->tblprop_array[i].offset;
389 
390 	return envctrl_i2c_data_translate(data, pchild->tblprop_array[i].type,
391 					  pchild->tblprop_array[i].scale,
392 					  tbl, bufdata);
393 }
394 
395 /* Function Description: Read noncpu-related data such as motherboard
396  *                       temperature.
397  * Return: Number of read bytes. Data is stored in bufdata in ascii format.
398  */
399 static int envctrl_read_noncpu_info(struct i2c_child_t *pchild,
400 				    char mon_type, unsigned char *bufdata)
401 {
402 	unsigned char data;
403 	int i;
404 	char *tbl = NULL;
405 
406 	for (i = 0; i < PCF8584_MAX_CHANNELS; i++) {
407 		if (pchild->mon_type[i] == mon_type)
408 			break;
409 	}
410 
411 	if (i >= PCF8584_MAX_CHANNELS)
412 		return 0;
413 
414         /* Read data from address and port. */
415 	data = envctrl_i2c_read_8591((unsigned char)pchild->addr,
416 				     (unsigned char)pchild->chnl_array[i].chnl_no);
417 
418 	/* Find decoding table. */
419 	tbl = pchild->tables + pchild->tblprop_array[i].offset;
420 
421 	return envctrl_i2c_data_translate(data, pchild->tblprop_array[i].type,
422 					  pchild->tblprop_array[i].scale,
423 					  tbl, bufdata);
424 }
425 
426 /* Function Description: Read fan status.
427  * Return : Always 1 byte. Status stored in bufdata.
428  */
429 static int envctrl_i2c_fan_status(struct i2c_child_t *pchild,
430 				  unsigned char data,
431 				  char *bufdata)
432 {
433 	unsigned char tmp, ret = 0;
434 	int i, j = 0;
435 
436 	tmp = data & pchild->fan_mask;
437 
438 	if (tmp == pchild->fan_mask) {
439 		/* All bits are on. All fans are functioning. */
440 		ret = ENVCTRL_ALL_FANS_GOOD;
441 	} else if (tmp == 0) {
442 		/* No bits are on. No fans are functioning. */
443 		ret = ENVCTRL_ALL_FANS_BAD;
444 	} else {
445 		/* Go through all channels, mark 'on' the matched bits.
446 		 * Notice that fan_mask may have discontiguous bits but
447 		 * return mask are always contiguous. For example if we
448 		 * monitor 4 fans at channels 0,1,2,4, the return mask
449 		 * should be 00010000 if only fan at channel 4 is working.
450 		 */
451 		for (i = 0; i < PCF8584_MAX_CHANNELS;i++) {
452 			if (pchild->fan_mask & chnls_mask[i]) {
453 				if (!(chnls_mask[i] & tmp))
454 					ret |= chnls_mask[j];
455 
456 				j++;
457 			}
458 		}
459 	}
460 
461 	bufdata[0] = ret;
462 	return 1;
463 }
464 
465 /* Function Description: Read global addressing line.
466  * Return : Always 1 byte. Status stored in bufdata.
467  */
468 static int envctrl_i2c_globaladdr(struct i2c_child_t *pchild,
469 				  unsigned char data,
470 				  char *bufdata)
471 {
472 	/* Translatation table is not necessary, as global
473 	 * addr is the integer value of the GA# bits.
474 	 *
475 	 * NOTE: MSB is documented as zero, but I see it as '1' always....
476 	 *
477 	 * -----------------------------------------------
478 	 * | 0 | FAL | DEG | GA4 | GA3 | GA2 | GA1 | GA0 |
479 	 * -----------------------------------------------
480 	 * GA0 - GA4	integer value of Global Address (backplane slot#)
481 	 * DEG			0 = cPCI Power supply output is starting to degrade
482 	 * 				1 = cPCI Power supply output is OK
483 	 * FAL			0 = cPCI Power supply has failed
484 	 * 				1 = cPCI Power supply output is OK
485 	 */
486 	bufdata[0] = (data & ENVCTRL_GLOBALADDR_ADDR_MASK);
487 	return 1;
488 }
489 
490 /* Function Description: Read standard voltage and power supply status.
491  * Return : Always 1 byte. Status stored in bufdata.
492  */
493 static unsigned char envctrl_i2c_voltage_status(struct i2c_child_t *pchild,
494 						unsigned char data,
495 						char *bufdata)
496 {
497 	unsigned char tmp, ret = 0;
498 	int i, j = 0;
499 
500 	tmp = data & pchild->voltage_mask;
501 
502 	/* Two channels are used to monitor voltage and power supply. */
503 	if (tmp == pchild->voltage_mask) {
504 		/* All bits are on. Voltage and power supply are okay. */
505 		ret = ENVCTRL_VOLTAGE_POWERSUPPLY_GOOD;
506 	} else if (tmp == 0) {
507 		/* All bits are off. Voltage and power supply are bad */
508 		ret = ENVCTRL_VOLTAGE_POWERSUPPLY_BAD;
509 	} else {
510 		/* Either voltage or power supply has problem. */
511 		for (i = 0; i < PCF8584_MAX_CHANNELS; i++) {
512 			if (pchild->voltage_mask & chnls_mask[i]) {
513 				j++;
514 
515 				/* Break out when there is a mismatch. */
516 				if (!(chnls_mask[i] & tmp))
517 					break;
518 			}
519 		}
520 
521 		/* Make a wish that hardware will always use the
522 		 * first channel for voltage and the second for
523 		 * power supply.
524 		 */
525 		if (j == 1)
526 			ret = ENVCTRL_VOLTAGE_BAD;
527 		else
528 			ret = ENVCTRL_POWERSUPPLY_BAD;
529 	}
530 
531 	bufdata[0] = ret;
532 	return 1;
533 }
534 
535 /* Function Description: Read a byte from /dev/envctrl. Mapped to user read().
536  * Return: Number of read bytes. 0 for error.
537  */
538 static ssize_t
539 envctrl_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
540 {
541 	struct i2c_child_t *pchild;
542 	unsigned char data[10];
543 	int ret = 0;
544 
545 	/* Get the type of read as decided in ioctl() call.
546 	 * Find the appropriate i2c child.
547 	 * Get the data and put back to the user buffer.
548 	 */
549 
550 	switch ((int)(long)file->private_data) {
551 	case ENVCTRL_RD_WARNING_TEMPERATURE:
552 		if (warning_temperature == 0)
553 			return 0;
554 
555 		data[0] = (unsigned char)(warning_temperature);
556 		ret = 1;
557 		if (copy_to_user(buf, data, ret))
558 			ret = -EFAULT;
559 		break;
560 
561 	case ENVCTRL_RD_SHUTDOWN_TEMPERATURE:
562 		if (shutdown_temperature == 0)
563 			return 0;
564 
565 		data[0] = (unsigned char)(shutdown_temperature);
566 		ret = 1;
567 		if (copy_to_user(buf, data, ret))
568 			ret = -EFAULT;
569 		break;
570 
571 	case ENVCTRL_RD_MTHRBD_TEMPERATURE:
572 		if (!(pchild = envctrl_get_i2c_child(ENVCTRL_MTHRBDTEMP_MON)))
573 			return 0;
574 		ret = envctrl_read_noncpu_info(pchild, ENVCTRL_MTHRBDTEMP_MON, data);
575 		if (copy_to_user(buf, data, ret))
576 			ret = -EFAULT;
577 		break;
578 
579 	case ENVCTRL_RD_CPU_TEMPERATURE:
580 		if (!(pchild = envctrl_get_i2c_child(ENVCTRL_CPUTEMP_MON)))
581 			return 0;
582 		ret = envctrl_read_cpu_info(read_cpu, pchild, ENVCTRL_CPUTEMP_MON, data);
583 
584 		/* Reset cpu to the default cpu0. */
585 		if (copy_to_user(buf, data, ret))
586 			ret = -EFAULT;
587 		break;
588 
589 	case ENVCTRL_RD_CPU_VOLTAGE:
590 		if (!(pchild = envctrl_get_i2c_child(ENVCTRL_CPUVOLTAGE_MON)))
591 			return 0;
592 		ret = envctrl_read_cpu_info(read_cpu, pchild, ENVCTRL_CPUVOLTAGE_MON, data);
593 
594 		/* Reset cpu to the default cpu0. */
595 		if (copy_to_user(buf, data, ret))
596 			ret = -EFAULT;
597 		break;
598 
599 	case ENVCTRL_RD_SCSI_TEMPERATURE:
600 		if (!(pchild = envctrl_get_i2c_child(ENVCTRL_SCSITEMP_MON)))
601 			return 0;
602 		ret = envctrl_read_noncpu_info(pchild, ENVCTRL_SCSITEMP_MON, data);
603 		if (copy_to_user(buf, data, ret))
604 			ret = -EFAULT;
605 		break;
606 
607 	case ENVCTRL_RD_ETHERNET_TEMPERATURE:
608 		if (!(pchild = envctrl_get_i2c_child(ENVCTRL_ETHERTEMP_MON)))
609 			return 0;
610 		ret = envctrl_read_noncpu_info(pchild, ENVCTRL_ETHERTEMP_MON, data);
611 		if (copy_to_user(buf, data, ret))
612 			ret = -EFAULT;
613 		break;
614 
615 	case ENVCTRL_RD_FAN_STATUS:
616 		if (!(pchild = envctrl_get_i2c_child(ENVCTRL_FANSTAT_MON)))
617 			return 0;
618 		data[0] = envctrl_i2c_read_8574(pchild->addr);
619 		ret = envctrl_i2c_fan_status(pchild,data[0], data);
620 		if (copy_to_user(buf, data, ret))
621 			ret = -EFAULT;
622 		break;
623 
624 	case ENVCTRL_RD_GLOBALADDRESS:
625 		if (!(pchild = envctrl_get_i2c_child(ENVCTRL_GLOBALADDR_MON)))
626 			return 0;
627 		data[0] = envctrl_i2c_read_8574(pchild->addr);
628 		ret = envctrl_i2c_globaladdr(pchild, data[0], data);
629 		if (copy_to_user(buf, data, ret))
630 			ret = -EFAULT;
631 		break;
632 
633 	case ENVCTRL_RD_VOLTAGE_STATUS:
634 		if (!(pchild = envctrl_get_i2c_child(ENVCTRL_VOLTAGESTAT_MON)))
635 			/* If voltage monitor not present, check for CPCI equivalent */
636 			if (!(pchild = envctrl_get_i2c_child(ENVCTRL_GLOBALADDR_MON)))
637 				return 0;
638 		data[0] = envctrl_i2c_read_8574(pchild->addr);
639 		ret = envctrl_i2c_voltage_status(pchild, data[0], data);
640 		if (copy_to_user(buf, data, ret))
641 			ret = -EFAULT;
642 		break;
643 
644 	default:
645 		break;
646 
647 	}
648 
649 	return ret;
650 }
651 
652 /* Function Description: Command what to read.  Mapped to user ioctl().
653  * Return: Gives 0 for implemented commands, -EINVAL otherwise.
654  */
655 static long
656 envctrl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
657 {
658 	char __user *infobuf;
659 
660 	switch (cmd) {
661 	case ENVCTRL_RD_WARNING_TEMPERATURE:
662 	case ENVCTRL_RD_SHUTDOWN_TEMPERATURE:
663 	case ENVCTRL_RD_MTHRBD_TEMPERATURE:
664 	case ENVCTRL_RD_FAN_STATUS:
665 	case ENVCTRL_RD_VOLTAGE_STATUS:
666 	case ENVCTRL_RD_ETHERNET_TEMPERATURE:
667 	case ENVCTRL_RD_SCSI_TEMPERATURE:
668 	case ENVCTRL_RD_GLOBALADDRESS:
669 		file->private_data = (void *)(long)cmd;
670 		break;
671 
672 	case ENVCTRL_RD_CPU_TEMPERATURE:
673 	case ENVCTRL_RD_CPU_VOLTAGE:
674 		/* Check to see if application passes in any cpu number,
675 		 * the default is cpu0.
676 		 */
677 		infobuf = (char __user *) arg;
678 		if (infobuf == NULL) {
679 			read_cpu = 0;
680 		}else {
681 			get_user(read_cpu, infobuf);
682 		}
683 
684 		/* Save the command for use when reading. */
685 		file->private_data = (void *)(long)cmd;
686 		break;
687 
688 	default:
689 		return -EINVAL;
690 	}
691 
692 	return 0;
693 }
694 
695 /* Function Description: open device. Mapped to user open().
696  * Return: Always 0.
697  */
698 static int
699 envctrl_open(struct inode *inode, struct file *file)
700 {
701 	file->private_data = NULL;
702 	return 0;
703 }
704 
705 /* Function Description: Open device. Mapped to user close().
706  * Return: Always 0.
707  */
708 static int
709 envctrl_release(struct inode *inode, struct file *file)
710 {
711 	return 0;
712 }
713 
714 static const struct file_operations envctrl_fops = {
715 	.owner =		THIS_MODULE,
716 	.read =			envctrl_read,
717 	.unlocked_ioctl =	envctrl_ioctl,
718 	.compat_ioctl =		compat_ptr_ioctl,
719 	.open =			envctrl_open,
720 	.release =		envctrl_release,
721 	.llseek =		noop_llseek,
722 };
723 
724 static struct miscdevice envctrl_dev = {
725 	ENVCTRL_MINOR,
726 	"envctrl",
727 	&envctrl_fops
728 };
729 
730 /* Function Description: Set monitor type based on firmware description.
731  * Return: None.
732  */
733 static void envctrl_set_mon(struct i2c_child_t *pchild,
734 			    const char *chnl_desc,
735 			    int chnl_no)
736 {
737 	/* Firmware only has temperature type.  It does not distinguish
738 	 * different kinds of temperatures.  We use channel description
739 	 * to disinguish them.
740 	 */
741 	if (!(strcmp(chnl_desc,"temp,cpu")) ||
742 	    !(strcmp(chnl_desc,"temp,cpu0")) ||
743 	    !(strcmp(chnl_desc,"temp,cpu1")) ||
744 	    !(strcmp(chnl_desc,"temp,cpu2")) ||
745 	    !(strcmp(chnl_desc,"temp,cpu3")))
746 		pchild->mon_type[chnl_no] = ENVCTRL_CPUTEMP_MON;
747 
748 	if (!(strcmp(chnl_desc,"vddcore,cpu0")) ||
749 	    !(strcmp(chnl_desc,"vddcore,cpu1")) ||
750 	    !(strcmp(chnl_desc,"vddcore,cpu2")) ||
751 	    !(strcmp(chnl_desc,"vddcore,cpu3")))
752 		pchild->mon_type[chnl_no] = ENVCTRL_CPUVOLTAGE_MON;
753 
754 	if (!(strcmp(chnl_desc,"temp,motherboard")))
755 		pchild->mon_type[chnl_no] = ENVCTRL_MTHRBDTEMP_MON;
756 
757 	if (!(strcmp(chnl_desc,"temp,scsi")))
758 		pchild->mon_type[chnl_no] = ENVCTRL_SCSITEMP_MON;
759 
760 	if (!(strcmp(chnl_desc,"temp,ethernet")))
761 		pchild->mon_type[chnl_no] = ENVCTRL_ETHERTEMP_MON;
762 }
763 
764 /* Function Description: Initialize monitor channel with channel desc,
765  *                       decoding tables, monitor type, optional properties.
766  * Return: None.
767  */
768 static void envctrl_init_adc(struct i2c_child_t *pchild, struct device_node *dp)
769 {
770 	int i = 0, len;
771 	const char *pos;
772 	const unsigned int *pval;
773 
774 	/* Firmware describe channels into a stream separated by a '\0'. */
775 	pos = of_get_property(dp, "channels-description", &len);
776 
777 	while (len > 0) {
778 		int l = strlen(pos) + 1;
779 		envctrl_set_mon(pchild, pos, i++);
780 		len -= l;
781 		pos += l;
782 	}
783 
784 	/* Get optional properties. */
785 	pval = of_get_property(dp, "warning-temp", NULL);
786 	if (pval)
787 		warning_temperature = *pval;
788 
789 	pval = of_get_property(dp, "shutdown-temp", NULL);
790 	if (pval)
791 		shutdown_temperature = *pval;
792 }
793 
794 /* Function Description: Initialize child device monitoring fan status.
795  * Return: None.
796  */
797 static void envctrl_init_fanstat(struct i2c_child_t *pchild)
798 {
799 	int i;
800 
801 	/* Go through all channels and set up the mask. */
802 	for (i = 0; i < pchild->total_chnls; i++)
803 		pchild->fan_mask |= chnls_mask[(pchild->chnl_array[i]).chnl_no];
804 
805 	/* We only need to know if this child has fan status monitored.
806 	 * We don't care which channels since we have the mask already.
807 	 */
808 	pchild->mon_type[0] = ENVCTRL_FANSTAT_MON;
809 }
810 
811 /* Function Description: Initialize child device for global addressing line.
812  * Return: None.
813  */
814 static void envctrl_init_globaladdr(struct i2c_child_t *pchild)
815 {
816 	int i;
817 
818 	/* Voltage/PowerSupply monitoring is piggybacked
819 	 * with Global Address on CompactPCI.  See comments
820 	 * within envctrl_i2c_globaladdr for bit assignments.
821 	 *
822 	 * The mask is created here by assigning mask bits to each
823 	 * bit position that represents PCF8584_VOLTAGE_TYPE data.
824 	 * Channel numbers are not consecutive within the globaladdr
825 	 * node (why?), so we use the actual counter value as chnls_mask
826 	 * index instead of the chnl_array[x].chnl_no value.
827 	 *
828 	 * NOTE: This loop could be replaced with a constant representing
829 	 * a mask of bits 5&6 (ENVCTRL_GLOBALADDR_PSTAT_MASK).
830 	 */
831 	for (i = 0; i < pchild->total_chnls; i++) {
832 		if (PCF8584_VOLTAGE_TYPE == pchild->chnl_array[i].type) {
833 			pchild->voltage_mask |= chnls_mask[i];
834 		}
835 	}
836 
837 	/* We only need to know if this child has global addressing
838 	 * line monitored.  We don't care which channels since we know
839 	 * the mask already (ENVCTRL_GLOBALADDR_ADDR_MASK).
840 	 */
841 	pchild->mon_type[0] = ENVCTRL_GLOBALADDR_MON;
842 }
843 
844 /* Initialize child device monitoring voltage status. */
845 static void envctrl_init_voltage_status(struct i2c_child_t *pchild)
846 {
847 	int i;
848 
849 	/* Go through all channels and set up the mask. */
850 	for (i = 0; i < pchild->total_chnls; i++)
851 		pchild->voltage_mask |= chnls_mask[(pchild->chnl_array[i]).chnl_no];
852 
853 	/* We only need to know if this child has voltage status monitored.
854 	 * We don't care which channels since we have the mask already.
855 	 */
856 	pchild->mon_type[0] = ENVCTRL_VOLTAGESTAT_MON;
857 }
858 
859 /* Function Description: Initialize i2c child device.
860  * Return: None.
861  */
862 static void envctrl_init_i2c_child(struct device_node *dp,
863 				   struct i2c_child_t *pchild)
864 {
865 	int len, i, tbls_size = 0;
866 	const void *pval;
867 
868 	/* Get device address. */
869 	pval = of_get_property(dp, "reg", &len);
870 	memcpy(&pchild->addr, pval, len);
871 
872 	/* Get tables property.  Read firmware temperature tables. */
873 	pval = of_get_property(dp, "translation", &len);
874 	if (pval && len > 0) {
875 		memcpy(pchild->tblprop_array, pval, len);
876                 pchild->total_tbls = len / sizeof(struct pcf8584_tblprop);
877 		for (i = 0; i < pchild->total_tbls; i++) {
878 			if ((pchild->tblprop_array[i].size + pchild->tblprop_array[i].offset) > tbls_size) {
879 				tbls_size = pchild->tblprop_array[i].size + pchild->tblprop_array[i].offset;
880 			}
881 		}
882 
883                 pchild->tables = kmalloc(tbls_size, GFP_KERNEL);
884 		if (pchild->tables == NULL){
885 			printk(KERN_ERR PFX "Failed to allocate table.\n");
886 			return;
887 		}
888 		pval = of_get_property(dp, "tables", &len);
889                 if (!pval || len <= 0) {
890 			printk(KERN_ERR PFX "Failed to get table.\n");
891 			return;
892 		}
893 		memcpy(pchild->tables, pval, len);
894 	}
895 
896 	/* SPARCengine ASM Reference Manual (ref. SMI doc 805-7581-04)
897 	 * sections 2.5, 3.5, 4.5 state node 0x70 for CP1400/1500 is
898 	 * "For Factory Use Only."
899 	 *
900 	 * We ignore the node on these platforms by assigning the
901 	 * 'NULL' monitor type.
902 	 */
903 	if (ENVCTRL_CPCI_IGNORED_NODE == pchild->addr) {
904 		struct device_node *root_node;
905 		int len;
906 
907 		root_node = of_find_node_by_path("/");
908 		if (of_node_name_eq(root_node, "SUNW,UltraSPARC-IIi-cEngine")) {
909 			for (len = 0; len < PCF8584_MAX_CHANNELS; ++len) {
910 				pchild->mon_type[len] = ENVCTRL_NOMON;
911 			}
912 			of_node_put(root_node);
913 			return;
914 		}
915 		of_node_put(root_node);
916 	}
917 
918 	/* Get the monitor channels. */
919 	pval = of_get_property(dp, "channels-in-use", &len);
920 	memcpy(pchild->chnl_array, pval, len);
921 	pchild->total_chnls = len / sizeof(struct pcf8584_channel);
922 
923 	for (i = 0; i < pchild->total_chnls; i++) {
924 		switch (pchild->chnl_array[i].type) {
925 		case PCF8584_TEMP_TYPE:
926 			envctrl_init_adc(pchild, dp);
927 			break;
928 
929 		case PCF8584_GLOBALADDR_TYPE:
930 			envctrl_init_globaladdr(pchild);
931 			i = pchild->total_chnls;
932 			break;
933 
934 		case PCF8584_FANSTAT_TYPE:
935 			envctrl_init_fanstat(pchild);
936 			i = pchild->total_chnls;
937 			break;
938 
939 		case PCF8584_VOLTAGE_TYPE:
940 			if (pchild->i2ctype == I2C_ADC) {
941 				envctrl_init_adc(pchild,dp);
942 			} else {
943 				envctrl_init_voltage_status(pchild);
944 			}
945 			i = pchild->total_chnls;
946 			break;
947 
948 		default:
949 			break;
950 		}
951 	}
952 }
953 
954 /* Function Description: Search the child device list for a device.
955  * Return : The i2c child if found. NULL otherwise.
956  */
957 static struct i2c_child_t *envctrl_get_i2c_child(unsigned char mon_type)
958 {
959 	int i, j;
960 
961 	for (i = 0; i < ENVCTRL_MAX_CPU*2; i++) {
962 		for (j = 0; j < PCF8584_MAX_CHANNELS; j++) {
963 			if (i2c_childlist[i].mon_type[j] == mon_type) {
964 				return (struct i2c_child_t *)(&(i2c_childlist[i]));
965 			}
966 		}
967 	}
968 	return NULL;
969 }
970 
971 static void envctrl_do_shutdown(void)
972 {
973 	static int inprog = 0;
974 
975 	if (inprog != 0)
976 		return;
977 
978 	inprog = 1;
979 	printk(KERN_CRIT "kenvctrld: WARNING: Shutting down the system now.\n");
980 	orderly_poweroff(true);
981 }
982 
983 static struct task_struct *kenvctrld_task;
984 
985 static int kenvctrld(void *__unused)
986 {
987 	int poll_interval;
988 	int whichcpu;
989 	char tempbuf[10];
990 	struct i2c_child_t *cputemp;
991 
992 	if (NULL == (cputemp = envctrl_get_i2c_child(ENVCTRL_CPUTEMP_MON))) {
993 		printk(KERN_ERR  PFX
994 		       "kenvctrld unable to monitor CPU temp-- exiting\n");
995 		return -ENODEV;
996 	}
997 
998 	poll_interval = 5000; /* TODO env_mon_interval */
999 
1000 	printk(KERN_INFO PFX "%s starting...\n", current->comm);
1001 	for (;;) {
1002 		msleep_interruptible(poll_interval);
1003 
1004 		if (kthread_should_stop())
1005 			break;
1006 
1007 		for (whichcpu = 0; whichcpu < ENVCTRL_MAX_CPU; ++whichcpu) {
1008 			if (0 < envctrl_read_cpu_info(whichcpu, cputemp,
1009 						      ENVCTRL_CPUTEMP_MON,
1010 						      tempbuf)) {
1011 				if (tempbuf[0] >= shutdown_temperature) {
1012 					printk(KERN_CRIT
1013 						"%s: WARNING: CPU%i temperature %i C meets or exceeds "\
1014 						"shutdown threshold %i C\n",
1015 						current->comm, whichcpu,
1016 						tempbuf[0], shutdown_temperature);
1017 					envctrl_do_shutdown();
1018 				}
1019 			}
1020 		}
1021 	}
1022 	printk(KERN_INFO PFX "%s exiting...\n", current->comm);
1023 	return 0;
1024 }
1025 
1026 static int envctrl_probe(struct platform_device *op)
1027 {
1028 	struct device_node *dp;
1029 	int index, err;
1030 
1031 	if (i2c)
1032 		return -EINVAL;
1033 
1034 	i2c = of_ioremap(&op->resource[0], 0, 0x2, DRIVER_NAME);
1035 	if (!i2c)
1036 		return -ENOMEM;
1037 
1038 	index = 0;
1039 	dp = op->dev.of_node->child;
1040 	while (dp) {
1041 		if (of_node_name_eq(dp, "gpio")) {
1042 			i2c_childlist[index].i2ctype = I2C_GPIO;
1043 			envctrl_init_i2c_child(dp, &(i2c_childlist[index++]));
1044 		} else if (of_node_name_eq(dp, "adc")) {
1045 			i2c_childlist[index].i2ctype = I2C_ADC;
1046 			envctrl_init_i2c_child(dp, &(i2c_childlist[index++]));
1047 		}
1048 
1049 		dp = dp->sibling;
1050 	}
1051 
1052 	/* Set device address. */
1053 	writeb(CONTROL_PIN, i2c + PCF8584_CSR);
1054 	writeb(PCF8584_ADDRESS, i2c + PCF8584_DATA);
1055 
1056 	/* Set system clock and SCL frequencies. */
1057 	writeb(CONTROL_PIN | CONTROL_ES1, i2c + PCF8584_CSR);
1058 	writeb(CLK_4_43 | BUS_CLK_90, i2c + PCF8584_DATA);
1059 
1060 	/* Enable serial interface. */
1061 	writeb(CONTROL_PIN | CONTROL_ES0 | CONTROL_ACK, i2c + PCF8584_CSR);
1062 	udelay(200);
1063 
1064 	/* Register the device as a minor miscellaneous device. */
1065 	err = misc_register(&envctrl_dev);
1066 	if (err) {
1067 		printk(KERN_ERR PFX "Unable to get misc minor %d\n",
1068 		       envctrl_dev.minor);
1069 		goto out_iounmap;
1070 	}
1071 
1072 	/* Note above traversal routine post-incremented 'i' to accommodate
1073 	 * a next child device, so we decrement before reverse-traversal of
1074 	 * child devices.
1075 	 */
1076 	printk(KERN_INFO PFX "Initialized ");
1077 	for (--index; index >= 0; --index) {
1078 		printk("[%s 0x%lx]%s",
1079 			(I2C_ADC == i2c_childlist[index].i2ctype) ? "adc" :
1080 			((I2C_GPIO == i2c_childlist[index].i2ctype) ? "gpio" : "unknown"),
1081 			i2c_childlist[index].addr, (0 == index) ? "\n" : " ");
1082 	}
1083 
1084 	kenvctrld_task = kthread_run(kenvctrld, NULL, "kenvctrld");
1085 	if (IS_ERR(kenvctrld_task)) {
1086 		err = PTR_ERR(kenvctrld_task);
1087 		goto out_deregister;
1088 	}
1089 
1090 	return 0;
1091 
1092 out_deregister:
1093 	misc_deregister(&envctrl_dev);
1094 out_iounmap:
1095 	of_iounmap(&op->resource[0], i2c, 0x2);
1096 	for (index = 0; index < ENVCTRL_MAX_CPU * 2; index++)
1097 		kfree(i2c_childlist[index].tables);
1098 
1099 	return err;
1100 }
1101 
1102 static int envctrl_remove(struct platform_device *op)
1103 {
1104 	int index;
1105 
1106 	kthread_stop(kenvctrld_task);
1107 
1108 	of_iounmap(&op->resource[0], i2c, 0x2);
1109 	misc_deregister(&envctrl_dev);
1110 
1111 	for (index = 0; index < ENVCTRL_MAX_CPU * 2; index++)
1112 		kfree(i2c_childlist[index].tables);
1113 
1114 	return 0;
1115 }
1116 
1117 static const struct of_device_id envctrl_match[] = {
1118 	{
1119 		.name = "i2c",
1120 		.compatible = "i2cpcf,8584",
1121 	},
1122 	{},
1123 };
1124 MODULE_DEVICE_TABLE(of, envctrl_match);
1125 
1126 static struct platform_driver envctrl_driver = {
1127 	.driver = {
1128 		.name = DRIVER_NAME,
1129 		.of_match_table = envctrl_match,
1130 	},
1131 	.probe		= envctrl_probe,
1132 	.remove		= envctrl_remove,
1133 };
1134 
1135 module_platform_driver(envctrl_driver);
1136 
1137 MODULE_LICENSE("GPL");
1138