1 /***************************************************************************
2 * Copyright (C) 2010-2012 Hans de Goede <hdegoede@redhat.com> *
4 * This program is free software; you can redistribute it and/or modify *
5 * it under the terms of the GNU General Public License as published by *
6 * the Free Software Foundation; either version 2 of the License, or *
7 * (at your option) any later version. *
9 * This program is distributed in the hope that it will be useful, *
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of *
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
12 * GNU General Public License for more details. *
14 * You should have received a copy of the GNU General Public License *
15 * along with this program; if not, write to the *
16 * Free Software Foundation, Inc., *
17 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
18 ***************************************************************************/
20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22 #include <linux/module.h>
23 #include <linux/init.h>
24 #include <linux/platform_device.h>
25 #include <linux/err.h>
27 #include <linux/acpi.h>
28 #include <linux/delay.h>
30 #include <linux/watchdog.h>
31 #include <linux/miscdevice.h>
32 #include <linux/uaccess.h>
33 #include <linux/slab.h>
34 #include "sch56xx-common.h"
36 /* Insmod parameters */
37 static int nowayout
= WATCHDOG_NOWAYOUT
;
38 module_param(nowayout
, int, 0);
39 MODULE_PARM_DESC(nowayout
, "Watchdog cannot be stopped once started (default="
40 __MODULE_STRING(WATCHDOG_NOWAYOUT
) ")");
42 #define SIO_SCH56XX_LD_EM 0x0C /* Embedded uController Logical Dev */
43 #define SIO_UNLOCK_KEY 0x55 /* Key to enable Super-I/O */
44 #define SIO_LOCK_KEY 0xAA /* Key to disable Super-I/O */
46 #define SIO_REG_LDSEL 0x07 /* Logical device select */
47 #define SIO_REG_DEVID 0x20 /* Device ID */
48 #define SIO_REG_ENABLE 0x30 /* Logical device enable */
49 #define SIO_REG_ADDR 0x66 /* Logical device address (2 bytes) */
51 #define SIO_SCH5627_ID 0xC6 /* Chipset ID */
52 #define SIO_SCH5636_ID 0xC7 /* Chipset ID */
54 #define REGION_LENGTH 10
56 #define SCH56XX_CMD_READ 0x02
57 #define SCH56XX_CMD_WRITE 0x03
59 /* Watchdog registers */
60 #define SCH56XX_REG_WDOG_PRESET 0x58B
61 #define SCH56XX_REG_WDOG_CONTROL 0x58C
62 #define SCH56XX_WDOG_TIME_BASE_SEC 0x01
63 #define SCH56XX_REG_WDOG_OUTPUT_ENABLE 0x58E
64 #define SCH56XX_WDOG_OUTPUT_ENABLE 0x02
66 struct sch56xx_watchdog_data
{
68 struct mutex
*io_lock
;
69 struct watchdog_info wdinfo
;
70 struct watchdog_device wddev
;
73 u8 watchdog_output_enable
;
76 static struct platform_device
*sch56xx_pdev
;
78 /* Super I/O functions */
79 static inline int superio_inb(int base
, int reg
)
85 static inline int superio_enter(int base
)
87 /* Don't step on other drivers' I/O space by accident */
88 if (!request_muxed_region(base
, 2, "sch56xx")) {
89 pr_err("I/O address 0x%04x already in use\n", base
);
93 outb(SIO_UNLOCK_KEY
, base
);
98 static inline void superio_select(int base
, int ld
)
100 outb(SIO_REG_LDSEL
, base
);
104 static inline void superio_exit(int base
)
106 outb(SIO_LOCK_KEY
, base
);
107 release_region(base
, 2);
110 static int sch56xx_send_cmd(u16 addr
, u8 cmd
, u16 reg
, u8 v
)
115 * According to SMSC for the commands we use the maximum time for
116 * the EM to respond is 15 ms, but testing shows in practice it
117 * responds within 15-32 reads, so we first busy poll, and if
118 * that fails sleep a bit and try again until we are way past
119 * the 15 ms maximum response time.
121 const int max_busy_polls
= 64;
122 const int max_lazy_polls
= 32;
124 /* (Optional) Write-Clear the EC to Host Mailbox Register */
128 /* Set Mailbox Address Pointer to first location in Region 1 */
129 outb(0x00, addr
+ 2);
130 outb(0x80, addr
+ 3);
132 /* Write Request Packet Header */
133 outb(cmd
, addr
+ 4); /* VREG Access Type read:0x02 write:0x03 */
134 outb(0x01, addr
+ 5); /* # of Entries: 1 Byte (8-bit) */
135 outb(0x04, addr
+ 2); /* Mailbox AP to first data entry loc. */
137 /* Write Value field */
138 if (cmd
== SCH56XX_CMD_WRITE
)
141 /* Write Address field */
142 outb(reg
& 0xff, addr
+ 6);
143 outb(reg
>> 8, addr
+ 7);
145 /* Execute the Random Access Command */
146 outb(0x01, addr
); /* Write 01h to the Host-to-EC register */
148 /* EM Interface Polling "Algorithm" */
149 for (i
= 0; i
< max_busy_polls
+ max_lazy_polls
; i
++) {
150 if (i
>= max_busy_polls
)
152 /* Read Interrupt source Register */
154 /* Write Clear the interrupt source bits */
157 /* Command Completed ? */
161 if (i
== max_busy_polls
+ max_lazy_polls
) {
162 pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n",
168 * According to SMSC we may need to retry this, but sofar I've always
169 * seen this succeed in 1 try.
171 for (i
= 0; i
< max_busy_polls
; i
++) {
172 /* Read EC-to-Host Register */
174 /* Command Completed ? */
179 pr_warn("EC reports: 0x%02x reading virtual register 0x%04hx\n",
180 (unsigned int)val
, reg
);
182 if (i
== max_busy_polls
) {
183 pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n",
189 * According to the SMSC app note we should now do:
191 * Set Mailbox Address Pointer to first location in Region 1 *
192 * outb(0x00, addr + 2);
193 * outb(0x80, addr + 3);
195 * But if we do that things don't work, so let's not.
198 /* Read Value field */
199 if (cmd
== SCH56XX_CMD_READ
)
200 return inb(addr
+ 4);
205 int sch56xx_read_virtual_reg(u16 addr
, u16 reg
)
207 return sch56xx_send_cmd(addr
, SCH56XX_CMD_READ
, reg
, 0);
209 EXPORT_SYMBOL(sch56xx_read_virtual_reg
);
211 int sch56xx_write_virtual_reg(u16 addr
, u16 reg
, u8 val
)
213 return sch56xx_send_cmd(addr
, SCH56XX_CMD_WRITE
, reg
, val
);
215 EXPORT_SYMBOL(sch56xx_write_virtual_reg
);
217 int sch56xx_read_virtual_reg16(u16 addr
, u16 reg
)
221 /* Read LSB first, this will cause the matching MSB to be latched */
222 lsb
= sch56xx_read_virtual_reg(addr
, reg
);
226 msb
= sch56xx_read_virtual_reg(addr
, reg
+ 1);
230 return lsb
| (msb
<< 8);
232 EXPORT_SYMBOL(sch56xx_read_virtual_reg16
);
234 int sch56xx_read_virtual_reg12(u16 addr
, u16 msb_reg
, u16 lsn_reg
,
239 /* Read MSB first, this will cause the matching LSN to be latched */
240 msb
= sch56xx_read_virtual_reg(addr
, msb_reg
);
244 lsn
= sch56xx_read_virtual_reg(addr
, lsn_reg
);
249 return (msb
<< 4) | (lsn
>> 4);
251 return (msb
<< 4) | (lsn
& 0x0f);
253 EXPORT_SYMBOL(sch56xx_read_virtual_reg12
);
259 static int watchdog_set_timeout(struct watchdog_device
*wddev
,
260 unsigned int timeout
)
262 struct sch56xx_watchdog_data
*data
= watchdog_get_drvdata(wddev
);
263 unsigned int resolution
;
267 /* 1 second or 60 second resolution? */
273 if (timeout
< resolution
|| timeout
> (resolution
* 255))
277 control
= data
->watchdog_control
| SCH56XX_WDOG_TIME_BASE_SEC
;
279 control
= data
->watchdog_control
& ~SCH56XX_WDOG_TIME_BASE_SEC
;
281 if (data
->watchdog_control
!= control
) {
282 mutex_lock(data
->io_lock
);
283 ret
= sch56xx_write_virtual_reg(data
->addr
,
284 SCH56XX_REG_WDOG_CONTROL
,
286 mutex_unlock(data
->io_lock
);
290 data
->watchdog_control
= control
;
294 * Remember new timeout value, but do not write as that (re)starts
295 * the watchdog countdown.
297 data
->watchdog_preset
= DIV_ROUND_UP(timeout
, resolution
);
298 wddev
->timeout
= data
->watchdog_preset
* resolution
;
303 static int watchdog_start(struct watchdog_device
*wddev
)
305 struct sch56xx_watchdog_data
*data
= watchdog_get_drvdata(wddev
);
310 * The sch56xx's watchdog cannot really be started / stopped
311 * it is always running, but we can avoid the timer expiring
312 * from causing a system reset by clearing the output enable bit.
314 * The sch56xx's watchdog will set the watchdog event bit, bit 0
315 * of the second interrupt source register (at base-address + 9),
316 * when the timer expires.
318 * This will only cause a system reset if the 0-1 flank happens when
319 * output enable is true. Setting output enable after the flank will
320 * not cause a reset, nor will the timer expiring a second time.
321 * This means we must clear the watchdog event bit in case it is set.
323 * The timer may still be running (after a recent watchdog_stop) and
324 * mere milliseconds away from expiring, so the timer must be reset
328 mutex_lock(data
->io_lock
);
330 /* 1. Reset the watchdog countdown counter */
331 ret
= sch56xx_write_virtual_reg(data
->addr
, SCH56XX_REG_WDOG_PRESET
,
332 data
->watchdog_preset
);
336 /* 2. Enable output */
337 val
= data
->watchdog_output_enable
| SCH56XX_WDOG_OUTPUT_ENABLE
;
338 ret
= sch56xx_write_virtual_reg(data
->addr
,
339 SCH56XX_REG_WDOG_OUTPUT_ENABLE
, val
);
343 data
->watchdog_output_enable
= val
;
345 /* 3. Clear the watchdog event bit if set */
346 val
= inb(data
->addr
+ 9);
348 outb(0x01, data
->addr
+ 9);
351 mutex_unlock(data
->io_lock
);
355 static int watchdog_trigger(struct watchdog_device
*wddev
)
357 struct sch56xx_watchdog_data
*data
= watchdog_get_drvdata(wddev
);
360 /* Reset the watchdog countdown counter */
361 mutex_lock(data
->io_lock
);
362 ret
= sch56xx_write_virtual_reg(data
->addr
, SCH56XX_REG_WDOG_PRESET
,
363 data
->watchdog_preset
);
364 mutex_unlock(data
->io_lock
);
369 static int watchdog_stop(struct watchdog_device
*wddev
)
371 struct sch56xx_watchdog_data
*data
= watchdog_get_drvdata(wddev
);
375 val
= data
->watchdog_output_enable
& ~SCH56XX_WDOG_OUTPUT_ENABLE
;
376 mutex_lock(data
->io_lock
);
377 ret
= sch56xx_write_virtual_reg(data
->addr
,
378 SCH56XX_REG_WDOG_OUTPUT_ENABLE
, val
);
379 mutex_unlock(data
->io_lock
);
383 data
->watchdog_output_enable
= val
;
387 static const struct watchdog_ops watchdog_ops
= {
388 .owner
= THIS_MODULE
,
389 .start
= watchdog_start
,
390 .stop
= watchdog_stop
,
391 .ping
= watchdog_trigger
,
392 .set_timeout
= watchdog_set_timeout
,
395 struct sch56xx_watchdog_data
*sch56xx_watchdog_register(struct device
*parent
,
396 u16 addr
, u32 revision
, struct mutex
*io_lock
, int check_enabled
)
398 struct sch56xx_watchdog_data
*data
;
399 int err
, control
, output_enable
;
401 /* Cache the watchdog registers */
404 sch56xx_read_virtual_reg(addr
, SCH56XX_REG_WDOG_CONTROL
);
406 sch56xx_read_virtual_reg(addr
, SCH56XX_REG_WDOG_OUTPUT_ENABLE
);
407 mutex_unlock(io_lock
);
411 if (output_enable
< 0)
413 if (check_enabled
&& !(output_enable
& SCH56XX_WDOG_OUTPUT_ENABLE
)) {
414 pr_warn("Watchdog not enabled by BIOS, not registering\n");
418 data
= kzalloc(sizeof(struct sch56xx_watchdog_data
), GFP_KERNEL
);
423 data
->io_lock
= io_lock
;
425 strlcpy(data
->wdinfo
.identity
, "sch56xx watchdog",
426 sizeof(data
->wdinfo
.identity
));
427 data
->wdinfo
.firmware_version
= revision
;
428 data
->wdinfo
.options
= WDIOF_KEEPALIVEPING
| WDIOF_SETTIMEOUT
;
430 data
->wdinfo
.options
|= WDIOF_MAGICCLOSE
;
432 data
->wddev
.info
= &data
->wdinfo
;
433 data
->wddev
.ops
= &watchdog_ops
;
434 data
->wddev
.parent
= parent
;
435 data
->wddev
.timeout
= 60;
436 data
->wddev
.min_timeout
= 1;
437 data
->wddev
.max_timeout
= 255 * 60;
439 set_bit(WDOG_NO_WAY_OUT
, &data
->wddev
.status
);
440 if (output_enable
& SCH56XX_WDOG_OUTPUT_ENABLE
)
441 set_bit(WDOG_ACTIVE
, &data
->wddev
.status
);
443 /* Since the watchdog uses a downcounter there is no register to read
444 the BIOS set timeout from (if any was set at all) ->
445 Choose a preset which will give us a 1 minute timeout */
446 if (control
& SCH56XX_WDOG_TIME_BASE_SEC
)
447 data
->watchdog_preset
= 60; /* seconds */
449 data
->watchdog_preset
= 1; /* minute */
451 data
->watchdog_control
= control
;
452 data
->watchdog_output_enable
= output_enable
;
454 watchdog_set_drvdata(&data
->wddev
, data
);
455 err
= watchdog_register_device(&data
->wddev
);
457 pr_err("Registering watchdog chardev: %d\n", err
);
464 EXPORT_SYMBOL(sch56xx_watchdog_register
);
466 void sch56xx_watchdog_unregister(struct sch56xx_watchdog_data
*data
)
468 watchdog_unregister_device(&data
->wddev
);
471 EXPORT_SYMBOL(sch56xx_watchdog_unregister
);
474 * platform dev find, add and remove functions
477 static int __init
sch56xx_find(int sioaddr
, const char **name
)
480 unsigned short address
;
483 err
= superio_enter(sioaddr
);
487 devid
= superio_inb(sioaddr
, SIO_REG_DEVID
);
496 pr_debug("Unsupported device id: 0x%02x\n",
497 (unsigned int)devid
);
502 superio_select(sioaddr
, SIO_SCH56XX_LD_EM
);
504 if (!(superio_inb(sioaddr
, SIO_REG_ENABLE
) & 0x01)) {
505 pr_warn("Device not activated\n");
511 * Warning the order of the low / high byte is the other way around
512 * as on most other superio devices!!
514 address
= superio_inb(sioaddr
, SIO_REG_ADDR
) |
515 superio_inb(sioaddr
, SIO_REG_ADDR
+ 1) << 8;
517 pr_warn("Base address not set\n");
524 superio_exit(sioaddr
);
528 static int __init
sch56xx_device_add(int address
, const char *name
)
530 struct resource res
= {
532 .end
= address
+ REGION_LENGTH
- 1,
533 .flags
= IORESOURCE_IO
,
537 sch56xx_pdev
= platform_device_alloc(name
, address
);
541 res
.name
= sch56xx_pdev
->name
;
542 err
= acpi_check_resource_conflict(&res
);
544 goto exit_device_put
;
546 err
= platform_device_add_resources(sch56xx_pdev
, &res
, 1);
548 pr_err("Device resource addition failed\n");
549 goto exit_device_put
;
552 err
= platform_device_add(sch56xx_pdev
);
554 pr_err("Device addition failed\n");
555 goto exit_device_put
;
561 platform_device_put(sch56xx_pdev
);
566 static int __init
sch56xx_init(void)
569 const char *name
= NULL
;
571 address
= sch56xx_find(0x4e, &name
);
573 address
= sch56xx_find(0x2e, &name
);
577 return sch56xx_device_add(address
, name
);
580 static void __exit
sch56xx_exit(void)
582 platform_device_unregister(sch56xx_pdev
);
585 MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code");
586 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
587 MODULE_LICENSE("GPL");
589 module_init(sch56xx_init
);
590 module_exit(sch56xx_exit
);