cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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pcwd.c (26550B)


      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * PC Watchdog Driver
      4 * by Ken Hollis (khollis@bitgate.com)
      5 *
      6 * Permission granted from Simon Machell (smachell@berkprod.com)
      7 * Written for the Linux Kernel, and GPLed by Ken Hollis
      8 *
      9 * 960107	Added request_region routines, modulized the whole thing.
     10 * 960108	Fixed end-of-file pointer (Thanks to Dan Hollis), added
     11 *		WD_TIMEOUT define.
     12 * 960216	Added eof marker on the file, and changed verbose messages.
     13 * 960716	Made functional and cosmetic changes to the source for
     14 *		inclusion in Linux 2.0.x kernels, thanks to Alan Cox.
     15 * 960717	Removed read/seek routines, replaced with ioctl.  Also, added
     16 *		check_region command due to Alan's suggestion.
     17 * 960821	Made changes to compile in newer 2.0.x kernels.  Added
     18 *		"cold reboot sense" entry.
     19 * 960825	Made a few changes to code, deleted some defines and made
     20 *		typedefs to replace them.  Made heartbeat reset only available
     21 *		via ioctl, and removed the write routine.
     22 * 960828	Added new items for PC Watchdog Rev.C card.
     23 * 960829	Changed around all of the IOCTLs, added new features,
     24 *		added watchdog disable/re-enable routines.  Added firmware
     25 *		version reporting.  Added read routine for temperature.
     26 *		Removed some extra defines, added an autodetect Revision
     27 *		routine.
     28 * 961006	Revised some documentation, fixed some cosmetic bugs.  Made
     29 *		drivers to panic the system if it's overheating at bootup.
     30 * 961118	Changed some verbiage on some of the output, tidied up
     31 *		code bits, and added compatibility to 2.1.x.
     32 * 970912	Enabled board on open and disable on close.
     33 * 971107	Took account of recent VFS changes (broke read).
     34 * 971210	Disable board on initialisation in case board already ticking.
     35 * 971222	Changed open/close for temperature handling
     36 *		Michael Meskes <meskes@debian.org>.
     37 * 980112	Used minor numbers from include/linux/miscdevice.h
     38 * 990403	Clear reset status after reading control status register in
     39 *		pcwd_showprevstate(). [Marc Boucher <marc@mbsi.ca>]
     40 * 990605	Made changes to code to support Firmware 1.22a, added
     41 *		fairly useless proc entry.
     42 * 990610	removed said useless proc code for the merge <alan>
     43 * 000403	Removed last traces of proc code. <davej>
     44 * 011214	Added nowayout module option to override
     45 *		CONFIG_WATCHDOG_NOWAYOUT <Matt_Domsch@dell.com>
     46 *		Added timeout module option to override default
     47 */
     48
     49/*
     50 *	A bells and whistles driver is available from http://www.pcwd.de/
     51 *	More info available at http://www.berkprod.com/ or
     52 *	http://www.pcwatchdog.com/
     53 */
     54
     55#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
     56
     57#include <linux/module.h>	/* For module specific items */
     58#include <linux/moduleparam.h>	/* For new moduleparam's */
     59#include <linux/types.h>	/* For standard types (like size_t) */
     60#include <linux/errno.h>	/* For the -ENODEV/... values */
     61#include <linux/kernel.h>	/* For printk/panic/... */
     62#include <linux/delay.h>	/* For mdelay function */
     63#include <linux/timer.h>	/* For timer related operations */
     64#include <linux/jiffies.h>	/* For jiffies stuff */
     65#include <linux/miscdevice.h>	/* For struct miscdevice */
     66#include <linux/watchdog.h>	/* For the watchdog specific items */
     67#include <linux/reboot.h>	/* For kernel_power_off() */
     68#include <linux/init.h>		/* For __init/__exit/... */
     69#include <linux/fs.h>		/* For file operations */
     70#include <linux/isa.h>		/* For isa devices */
     71#include <linux/ioport.h>	/* For io-port access */
     72#include <linux/spinlock.h>	/* For spin_lock/spin_unlock/... */
     73#include <linux/uaccess.h>	/* For copy_to_user/put_user/... */
     74#include <linux/io.h>		/* For inb/outb/... */
     75
     76/* Module and version information */
     77#define WATCHDOG_VERSION "1.20"
     78#define WATCHDOG_DATE "18 Feb 2007"
     79#define WATCHDOG_DRIVER_NAME "ISA-PC Watchdog"
     80#define WATCHDOG_NAME "pcwd"
     81#define DRIVER_VERSION WATCHDOG_DRIVER_NAME " driver, v" WATCHDOG_VERSION "\n"
     82
     83/*
     84 * It should be noted that PCWD_REVISION_B was removed because A and B
     85 * are essentially the same types of card, with the exception that B
     86 * has temperature reporting.  Since I didn't receive a Rev.B card,
     87 * the Rev.B card is not supported.  (It's a good thing too, as they
     88 * are no longer in production.)
     89 */
     90#define	PCWD_REVISION_A		1
     91#define	PCWD_REVISION_C		2
     92
     93/*
     94 * These are the auto-probe addresses available.
     95 *
     96 * Revision A only uses ports 0x270 and 0x370.  Revision C introduced 0x350.
     97 * Revision A has an address range of 2 addresses, while Revision C has 4.
     98 */
     99#define PCWD_ISA_NR_CARDS	3
    100static int pcwd_ioports[] = { 0x270, 0x350, 0x370, 0x000 };
    101
    102/*
    103 * These are the defines that describe the control status bits for the
    104 * PCI-PC Watchdog card.
    105*/
    106/* Port 1 : Control Status #1 for the PC Watchdog card, revision A. */
    107#define WD_WDRST		0x01	/* Previously reset state */
    108#define WD_T110			0x02	/* Temperature overheat sense */
    109#define WD_HRTBT		0x04	/* Heartbeat sense */
    110#define WD_RLY2			0x08	/* External relay triggered */
    111#define WD_SRLY2		0x80	/* Software external relay triggered */
    112/* Port 1 : Control Status #1 for the PC Watchdog card, revision C. */
    113#define WD_REVC_WTRP		0x01	/* Watchdog Trip status */
    114#define WD_REVC_HRBT		0x02	/* Watchdog Heartbeat */
    115#define WD_REVC_TTRP		0x04	/* Temperature Trip status */
    116#define WD_REVC_RL2A		0x08	/* Relay 2 activated by
    117							on-board processor */
    118#define WD_REVC_RL1A		0x10	/* Relay 1 active */
    119#define WD_REVC_R2DS		0x40	/* Relay 2 disable */
    120#define WD_REVC_RLY2		0x80	/* Relay 2 activated? */
    121/* Port 2 : Control Status #2 */
    122#define WD_WDIS			0x10	/* Watchdog Disabled */
    123#define WD_ENTP			0x20	/* Watchdog Enable Temperature Trip */
    124#define WD_SSEL			0x40	/* Watchdog Switch Select
    125							(1:SW1 <-> 0:SW2) */
    126#define WD_WCMD			0x80	/* Watchdog Command Mode */
    127
    128/* max. time we give an ISA watchdog card to process a command */
    129/* 500ms for each 4 bit response (according to spec.) */
    130#define ISA_COMMAND_TIMEOUT     1000
    131
    132/* Watchdog's internal commands */
    133#define CMD_ISA_IDLE			0x00
    134#define CMD_ISA_VERSION_INTEGER		0x01
    135#define CMD_ISA_VERSION_TENTH		0x02
    136#define CMD_ISA_VERSION_HUNDRETH	0x03
    137#define CMD_ISA_VERSION_MINOR		0x04
    138#define CMD_ISA_SWITCH_SETTINGS		0x05
    139#define CMD_ISA_RESET_PC		0x06
    140#define CMD_ISA_ARM_0			0x07
    141#define CMD_ISA_ARM_30			0x08
    142#define CMD_ISA_ARM_60			0x09
    143#define CMD_ISA_DELAY_TIME_2SECS	0x0A
    144#define CMD_ISA_DELAY_TIME_4SECS	0x0B
    145#define CMD_ISA_DELAY_TIME_8SECS	0x0C
    146#define CMD_ISA_RESET_RELAYS		0x0D
    147
    148/* Watchdog's Dip Switch heartbeat values */
    149static const int heartbeat_tbl[] = {
    150	20,	/* OFF-OFF-OFF	= 20 Sec  */
    151	40,	/* OFF-OFF-ON	= 40 Sec  */
    152	60,	/* OFF-ON-OFF	=  1 Min  */
    153	300,	/* OFF-ON-ON	=  5 Min  */
    154	600,	/* ON-OFF-OFF	= 10 Min  */
    155	1800,	/* ON-OFF-ON	= 30 Min  */
    156	3600,	/* ON-ON-OFF	=  1 Hour */
    157	7200,	/* ON-ON-ON	=  2 hour */
    158};
    159
    160/*
    161 * We are using an kernel timer to do the pinging of the watchdog
    162 * every ~500ms. We try to set the internal heartbeat of the
    163 * watchdog to 2 ms.
    164 */
    165
    166#define WDT_INTERVAL (HZ/2+1)
    167
    168/* We can only use 1 card due to the /dev/watchdog restriction */
    169static int cards_found;
    170
    171/* internal variables */
    172static unsigned long open_allowed;
    173static char expect_close;
    174static int temp_panic;
    175
    176/* this is private data for each ISA-PC watchdog card */
    177static struct {
    178	char fw_ver_str[6];		/* The cards firmware version */
    179	int revision;			/* The card's revision */
    180	int supports_temp;		/* Whether or not the card has
    181						a temperature device */
    182	int command_mode;		/* Whether or not the card is in
    183						command mode */
    184	int boot_status;		/* The card's boot status */
    185	int io_addr;			/* The cards I/O address */
    186	spinlock_t io_lock;		/* the lock for io operations */
    187	struct timer_list timer;	/* The timer that pings the watchdog */
    188	unsigned long next_heartbeat;	/* the next_heartbeat for the timer */
    189} pcwd_private;
    190
    191/* module parameters */
    192#define QUIET	0	/* Default */
    193#define VERBOSE	1	/* Verbose */
    194#define DEBUG	2	/* print fancy stuff too */
    195static int debug = QUIET;
    196module_param(debug, int, 0);
    197MODULE_PARM_DESC(debug,
    198		"Debug level: 0=Quiet, 1=Verbose, 2=Debug (default=0)");
    199
    200/* default heartbeat = delay-time from dip-switches */
    201#define WATCHDOG_HEARTBEAT 0
    202static int heartbeat = WATCHDOG_HEARTBEAT;
    203module_param(heartbeat, int, 0);
    204MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. "
    205	"(2 <= heartbeat <= 7200 or 0=delay-time from dip-switches, default="
    206				__MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
    207
    208static bool nowayout = WATCHDOG_NOWAYOUT;
    209module_param(nowayout, bool, 0);
    210MODULE_PARM_DESC(nowayout,
    211		"Watchdog cannot be stopped once started (default="
    212				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
    213
    214/*
    215 *	Internal functions
    216 */
    217
    218static int send_isa_command(int cmd)
    219{
    220	int i;
    221	int control_status;
    222	int port0, last_port0;	/* Double read for stabilising */
    223
    224	if (debug >= DEBUG)
    225		pr_debug("sending following data cmd=0x%02x\n", cmd);
    226
    227	/* The WCMD bit must be 1 and the command is only 4 bits in size */
    228	control_status = (cmd & 0x0F) | WD_WCMD;
    229	outb_p(control_status, pcwd_private.io_addr + 2);
    230	udelay(ISA_COMMAND_TIMEOUT);
    231
    232	port0 = inb_p(pcwd_private.io_addr);
    233	for (i = 0; i < 25; ++i) {
    234		last_port0 = port0;
    235		port0 = inb_p(pcwd_private.io_addr);
    236
    237		if (port0 == last_port0)
    238			break;	/* Data is stable */
    239
    240		udelay(250);
    241	}
    242
    243	if (debug >= DEBUG)
    244		pr_debug("received following data for cmd=0x%02x: port0=0x%02x last_port0=0x%02x\n",
    245			 cmd, port0, last_port0);
    246
    247	return port0;
    248}
    249
    250static int set_command_mode(void)
    251{
    252	int i, found = 0, count = 0;
    253
    254	/* Set the card into command mode */
    255	spin_lock(&pcwd_private.io_lock);
    256	while ((!found) && (count < 3)) {
    257		i = send_isa_command(CMD_ISA_IDLE);
    258
    259		if (i == 0x00)
    260			found = 1;
    261		else if (i == 0xF3) {
    262			/* Card does not like what we've done to it */
    263			outb_p(0x00, pcwd_private.io_addr + 2);
    264			udelay(1200);	/* Spec says wait 1ms */
    265			outb_p(0x00, pcwd_private.io_addr + 2);
    266			udelay(ISA_COMMAND_TIMEOUT);
    267		}
    268		count++;
    269	}
    270	spin_unlock(&pcwd_private.io_lock);
    271	pcwd_private.command_mode = found;
    272
    273	if (debug >= DEBUG)
    274		pr_debug("command_mode=%d\n", pcwd_private.command_mode);
    275
    276	return found;
    277}
    278
    279static void unset_command_mode(void)
    280{
    281	/* Set the card into normal mode */
    282	spin_lock(&pcwd_private.io_lock);
    283	outb_p(0x00, pcwd_private.io_addr + 2);
    284	udelay(ISA_COMMAND_TIMEOUT);
    285	spin_unlock(&pcwd_private.io_lock);
    286
    287	pcwd_private.command_mode = 0;
    288
    289	if (debug >= DEBUG)
    290		pr_debug("command_mode=%d\n", pcwd_private.command_mode);
    291}
    292
    293static inline void pcwd_check_temperature_support(void)
    294{
    295	if (inb(pcwd_private.io_addr) != 0xF0)
    296		pcwd_private.supports_temp = 1;
    297}
    298
    299static inline void pcwd_get_firmware(void)
    300{
    301	int one, ten, hund, minor;
    302
    303	strcpy(pcwd_private.fw_ver_str, "ERROR");
    304
    305	if (set_command_mode()) {
    306		one = send_isa_command(CMD_ISA_VERSION_INTEGER);
    307		ten = send_isa_command(CMD_ISA_VERSION_TENTH);
    308		hund = send_isa_command(CMD_ISA_VERSION_HUNDRETH);
    309		minor = send_isa_command(CMD_ISA_VERSION_MINOR);
    310		sprintf(pcwd_private.fw_ver_str, "%c.%c%c%c",
    311					one, ten, hund, minor);
    312	}
    313	unset_command_mode();
    314
    315	return;
    316}
    317
    318static inline int pcwd_get_option_switches(void)
    319{
    320	int option_switches = 0;
    321
    322	if (set_command_mode()) {
    323		/* Get switch settings */
    324		option_switches = send_isa_command(CMD_ISA_SWITCH_SETTINGS);
    325	}
    326
    327	unset_command_mode();
    328	return option_switches;
    329}
    330
    331static void pcwd_show_card_info(void)
    332{
    333	int option_switches;
    334
    335	/* Get some extra info from the hardware (in command/debug/diag mode) */
    336	if (pcwd_private.revision == PCWD_REVISION_A)
    337		pr_info("ISA-PC Watchdog (REV.A) detected at port 0x%04x\n",
    338			pcwd_private.io_addr);
    339	else if (pcwd_private.revision == PCWD_REVISION_C) {
    340		pcwd_get_firmware();
    341		pr_info("ISA-PC Watchdog (REV.C) detected at port 0x%04x (Firmware version: %s)\n",
    342			pcwd_private.io_addr, pcwd_private.fw_ver_str);
    343		option_switches = pcwd_get_option_switches();
    344		pr_info("Option switches (0x%02x): Temperature Reset Enable=%s, Power On Delay=%s\n",
    345			option_switches,
    346			((option_switches & 0x10) ? "ON" : "OFF"),
    347			((option_switches & 0x08) ? "ON" : "OFF"));
    348
    349		/* Reprogram internal heartbeat to 2 seconds */
    350		if (set_command_mode()) {
    351			send_isa_command(CMD_ISA_DELAY_TIME_2SECS);
    352			unset_command_mode();
    353		}
    354	}
    355
    356	if (pcwd_private.supports_temp)
    357		pr_info("Temperature Option Detected\n");
    358
    359	if (pcwd_private.boot_status & WDIOF_CARDRESET)
    360		pr_info("Previous reboot was caused by the card\n");
    361
    362	if (pcwd_private.boot_status & WDIOF_OVERHEAT) {
    363		pr_emerg("Card senses a CPU Overheat. Panicking!\n");
    364		pr_emerg("CPU Overheat\n");
    365	}
    366
    367	if (pcwd_private.boot_status == 0)
    368		pr_info("No previous trip detected - Cold boot or reset\n");
    369}
    370
    371static void pcwd_timer_ping(struct timer_list *unused)
    372{
    373	int wdrst_stat;
    374
    375	/* If we got a heartbeat pulse within the WDT_INTERVAL
    376	 * we agree to ping the WDT */
    377	if (time_before(jiffies, pcwd_private.next_heartbeat)) {
    378		/* Ping the watchdog */
    379		spin_lock(&pcwd_private.io_lock);
    380		if (pcwd_private.revision == PCWD_REVISION_A) {
    381			/*  Rev A cards are reset by setting the
    382			    WD_WDRST bit in register 1 */
    383			wdrst_stat = inb_p(pcwd_private.io_addr);
    384			wdrst_stat &= 0x0F;
    385			wdrst_stat |= WD_WDRST;
    386
    387			outb_p(wdrst_stat, pcwd_private.io_addr + 1);
    388		} else {
    389			/* Re-trigger watchdog by writing to port 0 */
    390			outb_p(0x00, pcwd_private.io_addr);
    391		}
    392
    393		/* Re-set the timer interval */
    394		mod_timer(&pcwd_private.timer, jiffies + WDT_INTERVAL);
    395
    396		spin_unlock(&pcwd_private.io_lock);
    397	} else {
    398		pr_warn("Heartbeat lost! Will not ping the watchdog\n");
    399	}
    400}
    401
    402static int pcwd_start(void)
    403{
    404	int stat_reg;
    405
    406	pcwd_private.next_heartbeat = jiffies + (heartbeat * HZ);
    407
    408	/* Start the timer */
    409	mod_timer(&pcwd_private.timer, jiffies + WDT_INTERVAL);
    410
    411	/* Enable the port */
    412	if (pcwd_private.revision == PCWD_REVISION_C) {
    413		spin_lock(&pcwd_private.io_lock);
    414		outb_p(0x00, pcwd_private.io_addr + 3);
    415		udelay(ISA_COMMAND_TIMEOUT);
    416		stat_reg = inb_p(pcwd_private.io_addr + 2);
    417		spin_unlock(&pcwd_private.io_lock);
    418		if (stat_reg & WD_WDIS) {
    419			pr_info("Could not start watchdog\n");
    420			return -EIO;
    421		}
    422	}
    423
    424	if (debug >= VERBOSE)
    425		pr_debug("Watchdog started\n");
    426
    427	return 0;
    428}
    429
    430static int pcwd_stop(void)
    431{
    432	int stat_reg;
    433
    434	/* Stop the timer */
    435	del_timer(&pcwd_private.timer);
    436
    437	/*  Disable the board  */
    438	if (pcwd_private.revision == PCWD_REVISION_C) {
    439		spin_lock(&pcwd_private.io_lock);
    440		outb_p(0xA5, pcwd_private.io_addr + 3);
    441		udelay(ISA_COMMAND_TIMEOUT);
    442		outb_p(0xA5, pcwd_private.io_addr + 3);
    443		udelay(ISA_COMMAND_TIMEOUT);
    444		stat_reg = inb_p(pcwd_private.io_addr + 2);
    445		spin_unlock(&pcwd_private.io_lock);
    446		if ((stat_reg & WD_WDIS) == 0) {
    447			pr_info("Could not stop watchdog\n");
    448			return -EIO;
    449		}
    450	}
    451
    452	if (debug >= VERBOSE)
    453		pr_debug("Watchdog stopped\n");
    454
    455	return 0;
    456}
    457
    458static int pcwd_keepalive(void)
    459{
    460	/* user land ping */
    461	pcwd_private.next_heartbeat = jiffies + (heartbeat * HZ);
    462
    463	if (debug >= DEBUG)
    464		pr_debug("Watchdog keepalive signal send\n");
    465
    466	return 0;
    467}
    468
    469static int pcwd_set_heartbeat(int t)
    470{
    471	if (t < 2 || t > 7200) /* arbitrary upper limit */
    472		return -EINVAL;
    473
    474	heartbeat = t;
    475
    476	if (debug >= VERBOSE)
    477		pr_debug("New heartbeat: %d\n", heartbeat);
    478
    479	return 0;
    480}
    481
    482static int pcwd_get_status(int *status)
    483{
    484	int control_status;
    485
    486	*status = 0;
    487	spin_lock(&pcwd_private.io_lock);
    488	if (pcwd_private.revision == PCWD_REVISION_A)
    489		/* Rev A cards return status information from
    490		 * the base register, which is used for the
    491		 * temperature in other cards. */
    492		control_status = inb(pcwd_private.io_addr);
    493	else {
    494		/* Rev C cards return card status in the base
    495		 * address + 1 register. And use different bits
    496		 * to indicate a card initiated reset, and an
    497		 * over-temperature condition. And the reboot
    498		 * status can be reset. */
    499		control_status = inb(pcwd_private.io_addr + 1);
    500	}
    501	spin_unlock(&pcwd_private.io_lock);
    502
    503	if (pcwd_private.revision == PCWD_REVISION_A) {
    504		if (control_status & WD_WDRST)
    505			*status |= WDIOF_CARDRESET;
    506
    507		if (control_status & WD_T110) {
    508			*status |= WDIOF_OVERHEAT;
    509			if (temp_panic) {
    510				pr_info("Temperature overheat trip!\n");
    511				kernel_power_off();
    512			}
    513		}
    514	} else {
    515		if (control_status & WD_REVC_WTRP)
    516			*status |= WDIOF_CARDRESET;
    517
    518		if (control_status & WD_REVC_TTRP) {
    519			*status |= WDIOF_OVERHEAT;
    520			if (temp_panic) {
    521				pr_info("Temperature overheat trip!\n");
    522				kernel_power_off();
    523			}
    524		}
    525	}
    526
    527	return 0;
    528}
    529
    530static int pcwd_clear_status(void)
    531{
    532	int control_status;
    533
    534	if (pcwd_private.revision == PCWD_REVISION_C) {
    535		spin_lock(&pcwd_private.io_lock);
    536
    537		if (debug >= VERBOSE)
    538			pr_info("clearing watchdog trip status\n");
    539
    540		control_status = inb_p(pcwd_private.io_addr + 1);
    541
    542		if (debug >= DEBUG) {
    543			pr_debug("status was: 0x%02x\n", control_status);
    544			pr_debug("sending: 0x%02x\n",
    545				 (control_status & WD_REVC_R2DS));
    546		}
    547
    548		/* clear reset status & Keep Relay 2 disable state as it is */
    549		outb_p((control_status & WD_REVC_R2DS),
    550						pcwd_private.io_addr + 1);
    551
    552		spin_unlock(&pcwd_private.io_lock);
    553	}
    554	return 0;
    555}
    556
    557static int pcwd_get_temperature(int *temperature)
    558{
    559	/* check that port 0 gives temperature info and no command results */
    560	if (pcwd_private.command_mode)
    561		return -1;
    562
    563	*temperature = 0;
    564	if (!pcwd_private.supports_temp)
    565		return -ENODEV;
    566
    567	/*
    568	 * Convert celsius to fahrenheit, since this was
    569	 * the decided 'standard' for this return value.
    570	 */
    571	spin_lock(&pcwd_private.io_lock);
    572	*temperature = ((inb(pcwd_private.io_addr)) * 9 / 5) + 32;
    573	spin_unlock(&pcwd_private.io_lock);
    574
    575	if (debug >= DEBUG) {
    576		pr_debug("temperature is: %d F\n", *temperature);
    577	}
    578
    579	return 0;
    580}
    581
    582/*
    583 *	/dev/watchdog handling
    584 */
    585
    586static long pcwd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
    587{
    588	int rv;
    589	int status;
    590	int temperature;
    591	int new_heartbeat;
    592	int __user *argp = (int __user *)arg;
    593	static const struct watchdog_info ident = {
    594		.options =		WDIOF_OVERHEAT |
    595					WDIOF_CARDRESET |
    596					WDIOF_KEEPALIVEPING |
    597					WDIOF_SETTIMEOUT |
    598					WDIOF_MAGICCLOSE,
    599		.firmware_version =	1,
    600		.identity =		"PCWD",
    601	};
    602
    603	switch (cmd) {
    604	case WDIOC_GETSUPPORT:
    605		if (copy_to_user(argp, &ident, sizeof(ident)))
    606			return -EFAULT;
    607		return 0;
    608
    609	case WDIOC_GETSTATUS:
    610		pcwd_get_status(&status);
    611		return put_user(status, argp);
    612
    613	case WDIOC_GETBOOTSTATUS:
    614		return put_user(pcwd_private.boot_status, argp);
    615
    616	case WDIOC_GETTEMP:
    617		if (pcwd_get_temperature(&temperature))
    618			return -EFAULT;
    619
    620		return put_user(temperature, argp);
    621
    622	case WDIOC_SETOPTIONS:
    623		if (pcwd_private.revision == PCWD_REVISION_C) {
    624			if (get_user(rv, argp))
    625				return -EFAULT;
    626
    627			if (rv & WDIOS_DISABLECARD) {
    628				status = pcwd_stop();
    629				if (status < 0)
    630					return status;
    631			}
    632			if (rv & WDIOS_ENABLECARD) {
    633				status = pcwd_start();
    634				if (status < 0)
    635					return status;
    636			}
    637			if (rv & WDIOS_TEMPPANIC)
    638				temp_panic = 1;
    639		}
    640		return -EINVAL;
    641
    642	case WDIOC_KEEPALIVE:
    643		pcwd_keepalive();
    644		return 0;
    645
    646	case WDIOC_SETTIMEOUT:
    647		if (get_user(new_heartbeat, argp))
    648			return -EFAULT;
    649
    650		if (pcwd_set_heartbeat(new_heartbeat))
    651			return -EINVAL;
    652
    653		pcwd_keepalive();
    654		fallthrough;
    655
    656	case WDIOC_GETTIMEOUT:
    657		return put_user(heartbeat, argp);
    658
    659	default:
    660		return -ENOTTY;
    661	}
    662
    663	return 0;
    664}
    665
    666static ssize_t pcwd_write(struct file *file, const char __user *buf, size_t len,
    667			  loff_t *ppos)
    668{
    669	if (len) {
    670		if (!nowayout) {
    671			size_t i;
    672
    673			/* In case it was set long ago */
    674			expect_close = 0;
    675
    676			for (i = 0; i != len; i++) {
    677				char c;
    678
    679				if (get_user(c, buf + i))
    680					return -EFAULT;
    681				if (c == 'V')
    682					expect_close = 42;
    683			}
    684		}
    685		pcwd_keepalive();
    686	}
    687	return len;
    688}
    689
    690static int pcwd_open(struct inode *inode, struct file *file)
    691{
    692	if (test_and_set_bit(0, &open_allowed))
    693		return -EBUSY;
    694	if (nowayout)
    695		__module_get(THIS_MODULE);
    696	/* Activate */
    697	pcwd_start();
    698	pcwd_keepalive();
    699	return stream_open(inode, file);
    700}
    701
    702static int pcwd_close(struct inode *inode, struct file *file)
    703{
    704	if (expect_close == 42)
    705		pcwd_stop();
    706	else {
    707		pr_crit("Unexpected close, not stopping watchdog!\n");
    708		pcwd_keepalive();
    709	}
    710	expect_close = 0;
    711	clear_bit(0, &open_allowed);
    712	return 0;
    713}
    714
    715/*
    716 *	/dev/temperature handling
    717 */
    718
    719static ssize_t pcwd_temp_read(struct file *file, char __user *buf, size_t count,
    720			 loff_t *ppos)
    721{
    722	int temperature;
    723
    724	if (pcwd_get_temperature(&temperature))
    725		return -EFAULT;
    726
    727	if (copy_to_user(buf, &temperature, 1))
    728		return -EFAULT;
    729
    730	return 1;
    731}
    732
    733static int pcwd_temp_open(struct inode *inode, struct file *file)
    734{
    735	if (!pcwd_private.supports_temp)
    736		return -ENODEV;
    737
    738	return stream_open(inode, file);
    739}
    740
    741static int pcwd_temp_close(struct inode *inode, struct file *file)
    742{
    743	return 0;
    744}
    745
    746/*
    747 *	Kernel Interfaces
    748 */
    749
    750static const struct file_operations pcwd_fops = {
    751	.owner		= THIS_MODULE,
    752	.llseek		= no_llseek,
    753	.write		= pcwd_write,
    754	.unlocked_ioctl	= pcwd_ioctl,
    755	.compat_ioctl	= compat_ptr_ioctl,
    756	.open		= pcwd_open,
    757	.release	= pcwd_close,
    758};
    759
    760static struct miscdevice pcwd_miscdev = {
    761	.minor =	WATCHDOG_MINOR,
    762	.name =		"watchdog",
    763	.fops =		&pcwd_fops,
    764};
    765
    766static const struct file_operations pcwd_temp_fops = {
    767	.owner		= THIS_MODULE,
    768	.llseek		= no_llseek,
    769	.read		= pcwd_temp_read,
    770	.open		= pcwd_temp_open,
    771	.release	= pcwd_temp_close,
    772};
    773
    774static struct miscdevice temp_miscdev = {
    775	.minor =	TEMP_MINOR,
    776	.name =		"temperature",
    777	.fops =		&pcwd_temp_fops,
    778};
    779
    780/*
    781 *	Init & exit routines
    782 */
    783
    784static inline int get_revision(void)
    785{
    786	int r = PCWD_REVISION_C;
    787
    788	spin_lock(&pcwd_private.io_lock);
    789	/* REV A cards use only 2 io ports; test
    790	 * presumes a floating bus reads as 0xff. */
    791	if ((inb(pcwd_private.io_addr + 2) == 0xFF) ||
    792	    (inb(pcwd_private.io_addr + 3) == 0xFF))
    793		r = PCWD_REVISION_A;
    794	spin_unlock(&pcwd_private.io_lock);
    795
    796	return r;
    797}
    798
    799/*
    800 *  The ISA cards have a heartbeat bit in one of the registers, which
    801 *  register is card dependent.  The heartbeat bit is monitored, and if
    802 *  found, is considered proof that a Berkshire card has been found.
    803 *  The initial rate is once per second at board start up, then twice
    804 *  per second for normal operation.
    805 */
    806static int pcwd_isa_match(struct device *dev, unsigned int id)
    807{
    808	int base_addr = pcwd_ioports[id];
    809	int port0, last_port0;	/* Reg 0, in case it's REV A */
    810	int port1, last_port1;	/* Register 1 for REV C cards */
    811	int i;
    812	int retval;
    813
    814	if (debug >= DEBUG)
    815		pr_debug("pcwd_isa_match id=%d\n", id);
    816
    817	if (!request_region(base_addr, 4, "PCWD")) {
    818		pr_info("Port 0x%04x unavailable\n", base_addr);
    819		return 0;
    820	}
    821
    822	retval = 0;
    823
    824	port0 = inb_p(base_addr);	/* For REV A boards */
    825	port1 = inb_p(base_addr + 1);	/* For REV C boards */
    826	if (port0 != 0xff || port1 != 0xff) {
    827		/* Not an 'ff' from a floating bus, so must be a card! */
    828		for (i = 0; i < 4; ++i) {
    829
    830			msleep(500);
    831
    832			last_port0 = port0;
    833			last_port1 = port1;
    834
    835			port0 = inb_p(base_addr);
    836			port1 = inb_p(base_addr + 1);
    837
    838			/* Has either hearbeat bit changed?  */
    839			if ((port0 ^ last_port0) & WD_HRTBT ||
    840			    (port1 ^ last_port1) & WD_REVC_HRBT) {
    841				retval = 1;
    842				break;
    843			}
    844		}
    845	}
    846	release_region(base_addr, 4);
    847
    848	return retval;
    849}
    850
    851static int pcwd_isa_probe(struct device *dev, unsigned int id)
    852{
    853	int ret;
    854
    855	if (debug >= DEBUG)
    856		pr_debug("pcwd_isa_probe id=%d\n", id);
    857
    858	cards_found++;
    859	if (cards_found == 1)
    860		pr_info("v%s Ken Hollis (kenji@bitgate.com)\n",
    861							WATCHDOG_VERSION);
    862
    863	if (cards_found > 1) {
    864		pr_err("This driver only supports 1 device\n");
    865		return -ENODEV;
    866	}
    867
    868	if (pcwd_ioports[id] == 0x0000) {
    869		pr_err("No I/O-Address for card detected\n");
    870		return -ENODEV;
    871	}
    872	pcwd_private.io_addr = pcwd_ioports[id];
    873
    874	spin_lock_init(&pcwd_private.io_lock);
    875
    876	/* Check card's revision */
    877	pcwd_private.revision = get_revision();
    878
    879	if (!request_region(pcwd_private.io_addr,
    880		(pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4, "PCWD")) {
    881		pr_err("I/O address 0x%04x already in use\n",
    882		       pcwd_private.io_addr);
    883		ret = -EIO;
    884		goto error_request_region;
    885	}
    886
    887	/* Initial variables */
    888	pcwd_private.supports_temp = 0;
    889	temp_panic = 0;
    890	pcwd_private.boot_status = 0x0000;
    891
    892	/* get the boot_status */
    893	pcwd_get_status(&pcwd_private.boot_status);
    894
    895	/* clear the "card caused reboot" flag */
    896	pcwd_clear_status();
    897
    898	timer_setup(&pcwd_private.timer, pcwd_timer_ping, 0);
    899
    900	/*  Disable the board  */
    901	pcwd_stop();
    902
    903	/*  Check whether or not the card supports the temperature device */
    904	pcwd_check_temperature_support();
    905
    906	/* Show info about the card itself */
    907	pcwd_show_card_info();
    908
    909	/* If heartbeat = 0 then we use the heartbeat from the dip-switches */
    910	if (heartbeat == 0)
    911		heartbeat = heartbeat_tbl[(pcwd_get_option_switches() & 0x07)];
    912
    913	/* Check that the heartbeat value is within it's range;
    914	   if not reset to the default */
    915	if (pcwd_set_heartbeat(heartbeat)) {
    916		pcwd_set_heartbeat(WATCHDOG_HEARTBEAT);
    917		pr_info("heartbeat value must be 2 <= heartbeat <= 7200, using %d\n",
    918			WATCHDOG_HEARTBEAT);
    919	}
    920
    921	if (pcwd_private.supports_temp) {
    922		ret = misc_register(&temp_miscdev);
    923		if (ret) {
    924			pr_err("cannot register miscdev on minor=%d (err=%d)\n",
    925			       TEMP_MINOR, ret);
    926			goto error_misc_register_temp;
    927		}
    928	}
    929
    930	ret = misc_register(&pcwd_miscdev);
    931	if (ret) {
    932		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
    933		       WATCHDOG_MINOR, ret);
    934		goto error_misc_register_watchdog;
    935	}
    936
    937	pr_info("initialized. heartbeat=%d sec (nowayout=%d)\n",
    938		heartbeat, nowayout);
    939
    940	return 0;
    941
    942error_misc_register_watchdog:
    943	if (pcwd_private.supports_temp)
    944		misc_deregister(&temp_miscdev);
    945error_misc_register_temp:
    946	release_region(pcwd_private.io_addr,
    947			(pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
    948error_request_region:
    949	pcwd_private.io_addr = 0x0000;
    950	cards_found--;
    951	return ret;
    952}
    953
    954static void pcwd_isa_remove(struct device *dev, unsigned int id)
    955{
    956	if (debug >= DEBUG)
    957		pr_debug("pcwd_isa_remove id=%d\n", id);
    958
    959	/*  Disable the board  */
    960	if (!nowayout)
    961		pcwd_stop();
    962
    963	/* Deregister */
    964	misc_deregister(&pcwd_miscdev);
    965	if (pcwd_private.supports_temp)
    966		misc_deregister(&temp_miscdev);
    967	release_region(pcwd_private.io_addr,
    968			(pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
    969	pcwd_private.io_addr = 0x0000;
    970	cards_found--;
    971}
    972
    973static void pcwd_isa_shutdown(struct device *dev, unsigned int id)
    974{
    975	if (debug >= DEBUG)
    976		pr_debug("pcwd_isa_shutdown id=%d\n", id);
    977
    978	pcwd_stop();
    979}
    980
    981static struct isa_driver pcwd_isa_driver = {
    982	.match		= pcwd_isa_match,
    983	.probe		= pcwd_isa_probe,
    984	.remove		= pcwd_isa_remove,
    985	.shutdown	= pcwd_isa_shutdown,
    986	.driver		= {
    987		.owner	= THIS_MODULE,
    988		.name	= WATCHDOG_NAME,
    989	},
    990};
    991
    992module_isa_driver(pcwd_isa_driver, PCWD_ISA_NR_CARDS);
    993
    994MODULE_AUTHOR("Ken Hollis <kenji@bitgate.com>, "
    995		"Wim Van Sebroeck <wim@iguana.be>");
    996MODULE_DESCRIPTION("Berkshire ISA-PC Watchdog driver");
    997MODULE_VERSION(WATCHDOG_VERSION);
    998MODULE_LICENSE("GPL");