Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  *	AMD Elan SC520 processor Watchdog Timer driver
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  *	Based on acquirewdt.c by Alan Cox,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  *	     and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  *	The authors do NOT admit liability nor provide warranty for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  *	any of this software. This material is provided "AS-IS" in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10)  *	the hope that it may be useful for others.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12)  *	(c) Copyright 2001    Scott Jennings <linuxdrivers@oro.net>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13)  *           9/27 - 2001      [Initial release]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15)  *	Additional fixes Alan Cox
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16)  *	-	Fixed formatting
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17)  *	-	Removed debug printks
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18)  *	-	Fixed SMP built kernel deadlock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19)  *	-	Switched to private locks not lock_kernel
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20)  *	-	Used ioremap/writew/readw
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21)  *	-	Added NOWAYOUT support
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22)  *	4/12 - 2002 Changes by Rob Radez <rob@osinvestor.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23)  *	-	Change comments
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24)  *	-	Eliminate fop_llseek
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25)  *	-	Change CONFIG_WATCHDOG_NOWAYOUT semantics
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26)  *	-	Add KERN_* tags to printks
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27)  *	-	fix possible wdt_is_open race
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28)  *	-	Report proper capabilities in watchdog_info
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29)  *	-	Add WDIOC_{GETSTATUS, GETBOOTSTATUS, SETTIMEOUT,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30)  *		GETTIMEOUT, SETOPTIONS} ioctls
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31)  *	09/8 - 2003 Changes by Wim Van Sebroeck <wim@iguana.be>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32)  *	-	cleanup of trailing spaces
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33)  *	-	added extra printk's for startup problems
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34)  *	-	use module_param
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35)  *	-	made timeout (the emulated heartbeat) a module_param
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36)  *	-	made the keepalive ping an internal subroutine
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37)  *	3/27 - 2004 Changes by Sean Young <sean@mess.org>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38)  *	-	set MMCR_BASE to 0xfffef000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39)  *	-	CBAR does not need to be read
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40)  *	-	removed debugging printks
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42)  *  This WDT driver is different from most other Linux WDT
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43)  *  drivers in that the driver will ping the watchdog by itself,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44)  *  because this particular WDT has a very short timeout (1.6
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45)  *  seconds) and it would be insane to count on any userspace
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46)  *  daemon always getting scheduled within that time frame.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48)  *  This driver uses memory mapped IO, and spinlock.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) #include <linux/moduleparam.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) #include <linux/types.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) #include <linux/timer.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) #include <linux/miscdevice.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) #include <linux/watchdog.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) #include <linux/fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) #include <linux/ioport.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) #include <linux/notifier.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) #include <linux/reboot.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) #include <linux/init.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) #include <linux/jiffies.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) #include <linux/io.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) #include <linux/uaccess.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70)  * The AMD Elan SC520 timeout value is 492us times a power of 2 (0-7)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72)  *   0: 492us    2: 1.01s    4: 4.03s   6: 16.22s
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73)  *   1: 503ms    3: 2.01s    5: 8.05s   7: 32.21s
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75)  * We will program the SC520 watchdog for a timeout of 2.01s.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76)  * If we reset the watchdog every ~250ms we should be safe.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) #define WDT_INTERVAL (HZ/4+1)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82)  * We must not require too good response from the userspace daemon.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83)  * Here we require the userspace daemon to send us a heartbeat
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84)  * char to /dev/watchdog every 30 seconds.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) #define WATCHDOG_TIMEOUT 30		/* 30 sec default timeout */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) static int timeout = WATCHDOG_TIMEOUT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) module_param(timeout, int, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) MODULE_PARM_DESC(timeout,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 	"Watchdog timeout in seconds. (1 <= timeout <= 3600, default="
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 				__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) static bool nowayout = WATCHDOG_NOWAYOUT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) module_param(nowayout, bool, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) MODULE_PARM_DESC(nowayout,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 		"Watchdog cannot be stopped once started (default="
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102)  * AMD Elan SC520 - Watchdog Timer Registers
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) #define MMCR_BASE	0xfffef000	/* The default base address */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) #define OFFS_WDTMRCTL	0xCB0	/* Watchdog Timer Control Register */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) /* WDT Control Register bit definitions */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) #define WDT_EXP_SEL_01	0x0001	/* [01] Time-out = 496 us (with 33 Mhz clk). */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) #define WDT_EXP_SEL_02	0x0002	/* [02] Time-out = 508 ms (with 33 Mhz clk). */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) #define WDT_EXP_SEL_03	0x0004	/* [03] Time-out = 1.02 s (with 33 Mhz clk). */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) #define WDT_EXP_SEL_04	0x0008	/* [04] Time-out = 2.03 s (with 33 Mhz clk). */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) #define WDT_EXP_SEL_05	0x0010	/* [05] Time-out = 4.07 s (with 33 Mhz clk). */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) #define WDT_EXP_SEL_06	0x0020	/* [06] Time-out = 8.13 s (with 33 Mhz clk). */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) #define WDT_EXP_SEL_07	0x0040	/* [07] Time-out = 16.27s (with 33 Mhz clk). */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) #define WDT_EXP_SEL_08	0x0080	/* [08] Time-out = 32.54s (with 33 Mhz clk). */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) #define WDT_IRQ_FLG	0x1000	/* [12] Interrupt Request Flag */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) #define WDT_WRST_ENB	0x4000	/* [14] Watchdog Timer Reset Enable */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) #define WDT_ENB		0x8000	/* [15] Watchdog Timer Enable */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) static __u16 __iomem *wdtmrctl;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) static void wdt_timer_ping(struct timer_list *);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) static DEFINE_TIMER(timer, wdt_timer_ping);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) static unsigned long next_heartbeat;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) static unsigned long wdt_is_open;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) static char wdt_expect_close;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) static DEFINE_SPINLOCK(wdt_spinlock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130)  *	Whack the dog
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) static void wdt_timer_ping(struct timer_list *unused)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 	/* If we got a heartbeat pulse within the WDT_US_INTERVAL
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 	 * we agree to ping the WDT
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	if (time_before(jiffies, next_heartbeat)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 		/* Ping the WDT */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 		spin_lock(&wdt_spinlock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 		writew(0xAAAA, wdtmrctl);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 		writew(0x5555, wdtmrctl);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 		spin_unlock(&wdt_spinlock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 		/* Re-set the timer interval */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 		mod_timer(&timer, jiffies + WDT_INTERVAL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 	} else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 		pr_warn("Heartbeat lost! Will not ping the watchdog\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152)  *	Utility routines
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) static void wdt_config(int writeval)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 	/* buy some time (ping) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 	spin_lock_irqsave(&wdt_spinlock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 	readw(wdtmrctl);	/* ensure write synchronization */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 	writew(0xAAAA, wdtmrctl);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 	writew(0x5555, wdtmrctl);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 	/* unlock WDT = make WDT configuration register writable one time */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	writew(0x3333, wdtmrctl);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	writew(0xCCCC, wdtmrctl);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	/* write WDT configuration register */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 	writew(writeval, wdtmrctl);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	spin_unlock_irqrestore(&wdt_spinlock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) static int wdt_startup(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	next_heartbeat = jiffies + (timeout * HZ);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	/* Start the timer */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 	mod_timer(&timer, jiffies + WDT_INTERVAL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 	/* Start the watchdog */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 	wdt_config(WDT_ENB | WDT_WRST_ENB | WDT_EXP_SEL_04);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 	pr_info("Watchdog timer is now enabled\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) static int wdt_turnoff(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 	/* Stop the timer */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 	del_timer_sync(&timer);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 	/* Stop the watchdog */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 	wdt_config(0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 	pr_info("Watchdog timer is now disabled...\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) static int wdt_keepalive(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 	/* user land ping */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 	next_heartbeat = jiffies + (timeout * HZ);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) static int wdt_set_heartbeat(int t)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 	if ((t < 1) || (t > 3600))	/* arbitrary upper limit */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 	timeout = t;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215)  *	/dev/watchdog handling
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) static ssize_t fop_write(struct file *file, const char __user *buf,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 						size_t count, loff_t *ppos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 	/* See if we got the magic character 'V' and reload the timer */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 	if (count) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 		if (!nowayout) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 			size_t ofs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 			/* note: just in case someone wrote the magic character
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 			 * five months ago... */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 			wdt_expect_close = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 			/* now scan */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 			for (ofs = 0; ofs != count; ofs++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 				char c;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 				if (get_user(c, buf + ofs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 					return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 				if (c == 'V')
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 					wdt_expect_close = 42;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 		/* Well, anyhow someone wrote to us, we should
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 		   return that favour */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 		wdt_keepalive();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) 	return count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) static int fop_open(struct inode *inode, struct file *file)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 	/* Just in case we're already talking to someone... */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 	if (test_and_set_bit(0, &wdt_is_open))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 		return -EBUSY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 	if (nowayout)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 		__module_get(THIS_MODULE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 	/* Good, fire up the show */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 	wdt_startup();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 	return stream_open(inode, file);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) static int fop_close(struct inode *inode, struct file *file)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 	if (wdt_expect_close == 42)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 		wdt_turnoff();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 	else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 		pr_crit("Unexpected close, not stopping watchdog!\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 		wdt_keepalive();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 	clear_bit(0, &wdt_is_open);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 	wdt_expect_close = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 	void __user *argp = (void __user *)arg;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 	int __user *p = argp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 	static const struct watchdog_info ident = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 							| WDIOF_MAGICCLOSE,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 		.firmware_version = 1,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 		.identity = "SC520",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) 	};
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) 	switch (cmd) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) 	case WDIOC_GETSUPPORT:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) 		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) 	case WDIOC_GETSTATUS:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 	case WDIOC_GETBOOTSTATUS:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) 		return put_user(0, p);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) 	case WDIOC_SETOPTIONS:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) 	{
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) 		int new_options, retval = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) 		if (get_user(new_options, p))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 			return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 		if (new_options & WDIOS_DISABLECARD) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) 			wdt_turnoff();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 			retval = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) 		if (new_options & WDIOS_ENABLECARD) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) 			wdt_startup();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) 			retval = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) 		return retval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) 	case WDIOC_KEEPALIVE:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) 		wdt_keepalive();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) 	case WDIOC_SETTIMEOUT:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) 	{
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) 		int new_timeout;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) 		if (get_user(new_timeout, p))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) 			return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) 		if (wdt_set_heartbeat(new_timeout))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) 			return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) 		wdt_keepalive();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) 		fallthrough;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) 	case WDIOC_GETTIMEOUT:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) 		return put_user(timeout, p);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) 	default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) 		return -ENOTTY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) static const struct file_operations wdt_fops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) 	.owner		= THIS_MODULE,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) 	.llseek		= no_llseek,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) 	.write		= fop_write,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) 	.open		= fop_open,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) 	.release	= fop_close,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) 	.unlocked_ioctl	= fop_ioctl,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339) 	.compat_ioctl	= compat_ptr_ioctl,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) static struct miscdevice wdt_miscdev = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) 	.minor	= WATCHDOG_MINOR,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) 	.name	= "watchdog",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) 	.fops	= &wdt_fops,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349)  *	Notifier for system down
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) 	void *unused)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) 	if (code == SYS_DOWN || code == SYS_HALT)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) 		wdt_turnoff();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) 	return NOTIFY_DONE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361)  *	The WDT needs to learn about soft shutdowns in order to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362)  *	turn the timebomb registers off.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365) static struct notifier_block wdt_notifier = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366) 	.notifier_call = wdt_notify_sys,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369) static void __exit sc520_wdt_unload(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371) 	if (!nowayout)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) 		wdt_turnoff();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) 	/* Deregister */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375) 	misc_deregister(&wdt_miscdev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376) 	unregister_reboot_notifier(&wdt_notifier);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377) 	iounmap(wdtmrctl);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) static int __init sc520_wdt_init(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382) 	int rc = -EBUSY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384) 	/* Check that the timeout value is within it's range ;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 385) 	   if not reset to the default */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 386) 	if (wdt_set_heartbeat(timeout)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 387) 		wdt_set_heartbeat(WATCHDOG_TIMEOUT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 388) 		pr_info("timeout value must be 1 <= timeout <= 3600, using %d\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 389) 			WATCHDOG_TIMEOUT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 390) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 391) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 392) 	wdtmrctl = ioremap(MMCR_BASE + OFFS_WDTMRCTL, 2);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 393) 	if (!wdtmrctl) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 394) 		pr_err("Unable to remap memory\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 395) 		rc = -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 396) 		goto err_out_region2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 397) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 398) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 399) 	rc = register_reboot_notifier(&wdt_notifier);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 400) 	if (rc) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 401) 		pr_err("cannot register reboot notifier (err=%d)\n", rc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 402) 		goto err_out_ioremap;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 403) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 404) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 405) 	rc = misc_register(&wdt_miscdev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 406) 	if (rc) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 407) 		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 408) 		       WATCHDOG_MINOR, rc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 409) 		goto err_out_notifier;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 410) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 411) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 412) 	pr_info("WDT driver for SC520 initialised. timeout=%d sec (nowayout=%d)\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 413) 		timeout, nowayout);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 414) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 415) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 416) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 417) err_out_notifier:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 418) 	unregister_reboot_notifier(&wdt_notifier);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 419) err_out_ioremap:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 420) 	iounmap(wdtmrctl);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 421) err_out_region2:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 422) 	return rc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 423) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 424) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 425) module_init(sc520_wdt_init);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 426) module_exit(sc520_wdt_unload);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 427) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 428) MODULE_AUTHOR("Scott and Bill Jennings");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 429) MODULE_DESCRIPTION(
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 430) 	"Driver for watchdog timer in AMD \"Elan\" SC520 uProcessor");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 431) MODULE_LICENSE("GPL");