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662 lines
16 KiB
662 lines
16 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* cpwd.c - driver implementation for hardware watchdog |
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* timers found on Sun Microsystems CP1400 and CP1500 boards. |
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* |
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* This device supports both the generic Linux watchdog |
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* interface and Solaris-compatible ioctls as best it is |
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* able. |
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* |
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* NOTE: CP1400 systems appear to have a defective intr_mask |
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* register on the PLD, preventing the disabling of |
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* timer interrupts. We use a timer to periodically |
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* reset 'stopped' watchdogs on affected platforms. |
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* |
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* Copyright (c) 2000 Eric Brower ([email protected]) |
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* Copyright (C) 2008 David S. Miller <[email protected]> |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/fs.h> |
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#include <linux/errno.h> |
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#include <linux/major.h> |
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#include <linux/miscdevice.h> |
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#include <linux/interrupt.h> |
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#include <linux/ioport.h> |
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#include <linux/timer.h> |
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#include <linux/compat.h> |
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#include <linux/slab.h> |
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#include <linux/mutex.h> |
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#include <linux/io.h> |
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#include <linux/of.h> |
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#include <linux/of_device.h> |
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#include <linux/uaccess.h> |
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|
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#include <asm/irq.h> |
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#include <asm/watchdog.h> |
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#define DRIVER_NAME "cpwd" |
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#define WD_OBPNAME "watchdog" |
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#define WD_BADMODEL "SUNW,501-5336" |
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#define WD_BTIMEOUT (jiffies + (HZ * 1000)) |
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#define WD_BLIMIT 0xFFFF |
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#define WD0_MINOR 212 |
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#define WD1_MINOR 213 |
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#define WD2_MINOR 214 |
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/* Internal driver definitions. */ |
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#define WD0_ID 0 |
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#define WD1_ID 1 |
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#define WD2_ID 2 |
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#define WD_NUMDEVS 3 |
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#define WD_INTR_OFF 0 |
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#define WD_INTR_ON 1 |
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#define WD_STAT_INIT 0x01 /* Watchdog timer is initialized */ |
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#define WD_STAT_BSTOP 0x02 /* Watchdog timer is brokenstopped */ |
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#define WD_STAT_SVCD 0x04 /* Watchdog interrupt occurred */ |
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|
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/* Register value definitions |
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*/ |
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#define WD0_INTR_MASK 0x01 /* Watchdog device interrupt masks */ |
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#define WD1_INTR_MASK 0x02 |
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#define WD2_INTR_MASK 0x04 |
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#define WD_S_RUNNING 0x01 /* Watchdog device status running */ |
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#define WD_S_EXPIRED 0x02 /* Watchdog device status expired */ |
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struct cpwd { |
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void __iomem *regs; |
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spinlock_t lock; |
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unsigned int irq; |
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unsigned long timeout; |
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bool enabled; |
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bool reboot; |
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bool broken; |
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bool initialized; |
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struct { |
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struct miscdevice misc; |
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void __iomem *regs; |
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u8 intr_mask; |
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u8 runstatus; |
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u16 timeout; |
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} devs[WD_NUMDEVS]; |
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}; |
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static DEFINE_MUTEX(cpwd_mutex); |
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static struct cpwd *cpwd_device; |
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|
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/* Sun uses Altera PLD EPF8820ATC144-4 |
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* providing three hardware watchdogs: |
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* |
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* 1) RIC - sends an interrupt when triggered |
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* 2) XIR - asserts XIR_B_RESET when triggered, resets CPU |
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* 3) POR - asserts POR_B_RESET when triggered, resets CPU, backplane, board |
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* |
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*** Timer register block definition (struct wd_timer_regblk) |
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* |
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* dcntr and limit registers (halfword access): |
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* ------------------- |
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* | 15 | ...| 1 | 0 | |
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* ------------------- |
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* |- counter val -| |
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* ------------------- |
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* dcntr - Current 16-bit downcounter value. |
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* When downcounter reaches '0' watchdog expires. |
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* Reading this register resets downcounter with |
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* 'limit' value. |
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* limit - 16-bit countdown value in 1/10th second increments. |
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* Writing this register begins countdown with input value. |
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* Reading from this register does not affect counter. |
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* NOTES: After watchdog reset, dcntr and limit contain '1' |
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* |
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* status register (byte access): |
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* --------------------------- |
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* | 7 | ... | 2 | 1 | 0 | |
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* --------------+------------ |
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* |- UNUSED -| EXP | RUN | |
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* --------------------------- |
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* status- Bit 0 - Watchdog is running |
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* Bit 1 - Watchdog has expired |
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* |
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*** PLD register block definition (struct wd_pld_regblk) |
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* |
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* intr_mask register (byte access): |
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* --------------------------------- |
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* | 7 | ... | 3 | 2 | 1 | 0 | |
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* +-------------+------------------ |
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* |- UNUSED -| WD3 | WD2 | WD1 | |
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* --------------------------------- |
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* WD3 - 1 == Interrupt disabled for watchdog 3 |
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* WD2 - 1 == Interrupt disabled for watchdog 2 |
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* WD1 - 1 == Interrupt disabled for watchdog 1 |
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* |
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* pld_status register (byte access): |
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* UNKNOWN, MAGICAL MYSTERY REGISTER |
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* |
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*/ |
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#define WD_TIMER_REGSZ 16 |
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#define WD0_OFF 0 |
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#define WD1_OFF (WD_TIMER_REGSZ * 1) |
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#define WD2_OFF (WD_TIMER_REGSZ * 2) |
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#define PLD_OFF (WD_TIMER_REGSZ * 3) |
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#define WD_DCNTR 0x00 |
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#define WD_LIMIT 0x04 |
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#define WD_STATUS 0x08 |
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#define PLD_IMASK (PLD_OFF + 0x00) |
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#define PLD_STATUS (PLD_OFF + 0x04) |
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static struct timer_list cpwd_timer; |
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static int wd0_timeout; |
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static int wd1_timeout; |
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static int wd2_timeout; |
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module_param(wd0_timeout, int, 0); |
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MODULE_PARM_DESC(wd0_timeout, "Default watchdog0 timeout in 1/10secs"); |
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module_param(wd1_timeout, int, 0); |
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MODULE_PARM_DESC(wd1_timeout, "Default watchdog1 timeout in 1/10secs"); |
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module_param(wd2_timeout, int, 0); |
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MODULE_PARM_DESC(wd2_timeout, "Default watchdog2 timeout in 1/10secs"); |
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MODULE_AUTHOR("Eric Brower <[email protected]>"); |
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MODULE_DESCRIPTION("Hardware watchdog driver for Sun Microsystems CP1400/1500"); |
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MODULE_LICENSE("GPL"); |
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static void cpwd_writew(u16 val, void __iomem *addr) |
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{ |
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writew(cpu_to_le16(val), addr); |
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} |
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static u16 cpwd_readw(void __iomem *addr) |
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{ |
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u16 val = readw(addr); |
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return le16_to_cpu(val); |
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} |
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static void cpwd_writeb(u8 val, void __iomem *addr) |
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{ |
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writeb(val, addr); |
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} |
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static u8 cpwd_readb(void __iomem *addr) |
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{ |
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return readb(addr); |
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} |
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|
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/* Enable or disable watchdog interrupts |
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* Because of the CP1400 defect this should only be |
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* called during initialzation or by wd_[start|stop]timer() |
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* |
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* index - sub-device index, or -1 for 'all' |
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* enable - non-zero to enable interrupts, zero to disable |
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*/ |
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static void cpwd_toggleintr(struct cpwd *p, int index, int enable) |
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{ |
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unsigned char curregs = cpwd_readb(p->regs + PLD_IMASK); |
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unsigned char setregs = |
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(index == -1) ? |
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(WD0_INTR_MASK | WD1_INTR_MASK | WD2_INTR_MASK) : |
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(p->devs[index].intr_mask); |
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if (enable == WD_INTR_ON) |
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curregs &= ~setregs; |
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else |
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curregs |= setregs; |
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cpwd_writeb(curregs, p->regs + PLD_IMASK); |
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} |
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/* Restarts timer with maximum limit value and |
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* does not unset 'brokenstop' value. |
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*/ |
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static void cpwd_resetbrokentimer(struct cpwd *p, int index) |
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{ |
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cpwd_toggleintr(p, index, WD_INTR_ON); |
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cpwd_writew(WD_BLIMIT, p->devs[index].regs + WD_LIMIT); |
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} |
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/* Timer method called to reset stopped watchdogs-- |
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* because of the PLD bug on CP1400, we cannot mask |
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* interrupts within the PLD so me must continually |
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* reset the timers ad infinitum. |
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*/ |
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static void cpwd_brokentimer(struct timer_list *unused) |
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{ |
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struct cpwd *p = cpwd_device; |
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int id, tripped = 0; |
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/* kill a running timer instance, in case we |
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* were called directly instead of by kernel timer |
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*/ |
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if (timer_pending(&cpwd_timer)) |
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del_timer(&cpwd_timer); |
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for (id = 0; id < WD_NUMDEVS; id++) { |
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if (p->devs[id].runstatus & WD_STAT_BSTOP) { |
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++tripped; |
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cpwd_resetbrokentimer(p, id); |
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} |
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} |
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if (tripped) { |
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/* there is at least one timer brokenstopped-- reschedule */ |
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cpwd_timer.expires = WD_BTIMEOUT; |
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add_timer(&cpwd_timer); |
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} |
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} |
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/* Reset countdown timer with 'limit' value and continue countdown. |
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* This will not start a stopped timer. |
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*/ |
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static void cpwd_pingtimer(struct cpwd *p, int index) |
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{ |
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if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING) |
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cpwd_readw(p->devs[index].regs + WD_DCNTR); |
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} |
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/* Stop a running watchdog timer-- the timer actually keeps |
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* running, but the interrupt is masked so that no action is |
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* taken upon expiration. |
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*/ |
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static void cpwd_stoptimer(struct cpwd *p, int index) |
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{ |
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if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING) { |
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cpwd_toggleintr(p, index, WD_INTR_OFF); |
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if (p->broken) { |
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p->devs[index].runstatus |= WD_STAT_BSTOP; |
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cpwd_brokentimer(NULL); |
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} |
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} |
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} |
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/* Start a watchdog timer with the specified limit value |
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* If the watchdog is running, it will be restarted with |
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* the provided limit value. |
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* |
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* This function will enable interrupts on the specified |
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* watchdog. |
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*/ |
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static void cpwd_starttimer(struct cpwd *p, int index) |
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{ |
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if (p->broken) |
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p->devs[index].runstatus &= ~WD_STAT_BSTOP; |
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p->devs[index].runstatus &= ~WD_STAT_SVCD; |
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cpwd_writew(p->devs[index].timeout, p->devs[index].regs + WD_LIMIT); |
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cpwd_toggleintr(p, index, WD_INTR_ON); |
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} |
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static int cpwd_getstatus(struct cpwd *p, int index) |
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{ |
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unsigned char stat = cpwd_readb(p->devs[index].regs + WD_STATUS); |
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unsigned char intr = cpwd_readb(p->devs[index].regs + PLD_IMASK); |
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unsigned char ret = WD_STOPPED; |
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/* determine STOPPED */ |
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if (!stat) |
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return ret; |
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/* determine EXPIRED vs FREERUN vs RUNNING */ |
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else if (WD_S_EXPIRED & stat) { |
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ret = WD_EXPIRED; |
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} else if (WD_S_RUNNING & stat) { |
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if (intr & p->devs[index].intr_mask) { |
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ret = WD_FREERUN; |
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} else { |
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/* Fudge WD_EXPIRED status for defective CP1400-- |
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* IF timer is running |
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* AND brokenstop is set |
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* AND an interrupt has been serviced |
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* we are WD_EXPIRED. |
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* |
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* IF timer is running |
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* AND brokenstop is set |
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* AND no interrupt has been serviced |
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* we are WD_FREERUN. |
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*/ |
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if (p->broken && |
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(p->devs[index].runstatus & WD_STAT_BSTOP)) { |
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if (p->devs[index].runstatus & WD_STAT_SVCD) { |
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ret = WD_EXPIRED; |
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} else { |
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/* we could as well pretend |
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* we are expired */ |
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ret = WD_FREERUN; |
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} |
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} else { |
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ret = WD_RUNNING; |
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} |
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} |
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} |
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/* determine SERVICED */ |
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if (p->devs[index].runstatus & WD_STAT_SVCD) |
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ret |= WD_SERVICED; |
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return ret; |
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} |
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static irqreturn_t cpwd_interrupt(int irq, void *dev_id) |
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{ |
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struct cpwd *p = dev_id; |
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/* Only WD0 will interrupt-- others are NMI and we won't |
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* see them here.... |
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*/ |
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spin_lock_irq(&p->lock); |
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cpwd_stoptimer(p, WD0_ID); |
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p->devs[WD0_ID].runstatus |= WD_STAT_SVCD; |
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spin_unlock_irq(&p->lock); |
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return IRQ_HANDLED; |
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} |
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static int cpwd_open(struct inode *inode, struct file *f) |
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{ |
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struct cpwd *p = cpwd_device; |
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mutex_lock(&cpwd_mutex); |
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switch (iminor(inode)) { |
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case WD0_MINOR: |
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case WD1_MINOR: |
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case WD2_MINOR: |
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break; |
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default: |
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mutex_unlock(&cpwd_mutex); |
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return -ENODEV; |
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} |
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/* Register IRQ on first open of device */ |
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if (!p->initialized) { |
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if (request_irq(p->irq, &cpwd_interrupt, |
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IRQF_SHARED, DRIVER_NAME, p)) { |
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pr_err("Cannot register IRQ %d\n", p->irq); |
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mutex_unlock(&cpwd_mutex); |
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return -EBUSY; |
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} |
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p->initialized = true; |
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} |
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mutex_unlock(&cpwd_mutex); |
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return stream_open(inode, f); |
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} |
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static int cpwd_release(struct inode *inode, struct file *file) |
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{ |
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return 0; |
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} |
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static long cpwd_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
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{ |
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static const struct watchdog_info info = { |
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.options = WDIOF_SETTIMEOUT, |
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.firmware_version = 1, |
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.identity = DRIVER_NAME, |
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}; |
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void __user *argp = (void __user *)arg; |
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struct inode *inode = file_inode(file); |
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int index = iminor(inode) - WD0_MINOR; |
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struct cpwd *p = cpwd_device; |
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int setopt = 0; |
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switch (cmd) { |
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/* Generic Linux IOCTLs */ |
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case WDIOC_GETSUPPORT: |
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if (copy_to_user(argp, &info, sizeof(struct watchdog_info))) |
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return -EFAULT; |
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break; |
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case WDIOC_GETSTATUS: |
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case WDIOC_GETBOOTSTATUS: |
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if (put_user(0, (int __user *)argp)) |
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return -EFAULT; |
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break; |
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case WDIOC_KEEPALIVE: |
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cpwd_pingtimer(p, index); |
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break; |
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case WDIOC_SETOPTIONS: |
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if (copy_from_user(&setopt, argp, sizeof(unsigned int))) |
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return -EFAULT; |
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if (setopt & WDIOS_DISABLECARD) { |
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if (p->enabled) |
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return -EINVAL; |
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cpwd_stoptimer(p, index); |
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} else if (setopt & WDIOS_ENABLECARD) { |
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cpwd_starttimer(p, index); |
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} else { |
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return -EINVAL; |
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} |
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break; |
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/* Solaris-compatible IOCTLs */ |
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case WIOCGSTAT: |
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setopt = cpwd_getstatus(p, index); |
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if (copy_to_user(argp, &setopt, sizeof(unsigned int))) |
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return -EFAULT; |
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break; |
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case WIOCSTART: |
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cpwd_starttimer(p, index); |
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break; |
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case WIOCSTOP: |
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if (p->enabled) |
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return -EINVAL; |
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cpwd_stoptimer(p, index); |
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break; |
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default: |
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return -EINVAL; |
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} |
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return 0; |
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} |
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static long cpwd_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
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{ |
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return cpwd_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); |
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} |
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static ssize_t cpwd_write(struct file *file, const char __user *buf, |
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size_t count, loff_t *ppos) |
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{ |
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struct inode *inode = file_inode(file); |
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struct cpwd *p = cpwd_device; |
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int index = iminor(inode); |
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if (count) { |
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cpwd_pingtimer(p, index); |
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return 1; |
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} |
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return 0; |
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} |
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static ssize_t cpwd_read(struct file *file, char __user *buffer, |
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size_t count, loff_t *ppos) |
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{ |
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return -EINVAL; |
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} |
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static const struct file_operations cpwd_fops = { |
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.owner = THIS_MODULE, |
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.unlocked_ioctl = cpwd_ioctl, |
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.compat_ioctl = cpwd_compat_ioctl, |
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.open = cpwd_open, |
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.write = cpwd_write, |
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.read = cpwd_read, |
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.release = cpwd_release, |
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.llseek = no_llseek, |
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}; |
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static int cpwd_probe(struct platform_device *op) |
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{ |
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struct device_node *options; |
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const char *str_prop; |
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const void *prop_val; |
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int i, err = -EINVAL; |
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struct cpwd *p; |
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if (cpwd_device) |
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return -EINVAL; |
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p = devm_kzalloc(&op->dev, sizeof(*p), GFP_KERNEL); |
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if (!p) |
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return -ENOMEM; |
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p->irq = op->archdata.irqs[0]; |
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spin_lock_init(&p->lock); |
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p->regs = of_ioremap(&op->resource[0], 0, |
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4 * WD_TIMER_REGSZ, DRIVER_NAME); |
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if (!p->regs) { |
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pr_err("Unable to map registers\n"); |
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return -ENOMEM; |
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} |
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options = of_find_node_by_path("/options"); |
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if (!options) { |
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err = -ENODEV; |
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pr_err("Unable to find /options node\n"); |
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goto out_iounmap; |
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} |
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prop_val = of_get_property(options, "watchdog-enable?", NULL); |
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p->enabled = (prop_val ? true : false); |
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prop_val = of_get_property(options, "watchdog-reboot?", NULL); |
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p->reboot = (prop_val ? true : false); |
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str_prop = of_get_property(options, "watchdog-timeout", NULL); |
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if (str_prop) |
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p->timeout = simple_strtoul(str_prop, NULL, 10); |
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of_node_put(options); |
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|
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/* CP1400s seem to have broken PLD implementations-- the |
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* interrupt_mask register cannot be written, so no timer |
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* interrupts can be masked within the PLD. |
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*/ |
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str_prop = of_get_property(op->dev.of_node, "model", NULL); |
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p->broken = (str_prop && !strcmp(str_prop, WD_BADMODEL)); |
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|
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if (!p->enabled) |
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cpwd_toggleintr(p, -1, WD_INTR_OFF); |
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|
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for (i = 0; i < WD_NUMDEVS; i++) { |
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static const char *cpwd_names[] = { "RIC", "XIR", "POR" }; |
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static int *parms[] = { &wd0_timeout, |
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&wd1_timeout, |
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&wd2_timeout }; |
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struct miscdevice *mp = &p->devs[i].misc; |
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mp->minor = WD0_MINOR + i; |
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mp->name = cpwd_names[i]; |
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mp->fops = &cpwd_fops; |
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|
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p->devs[i].regs = p->regs + (i * WD_TIMER_REGSZ); |
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p->devs[i].intr_mask = (WD0_INTR_MASK << i); |
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p->devs[i].runstatus &= ~WD_STAT_BSTOP; |
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p->devs[i].runstatus |= WD_STAT_INIT; |
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p->devs[i].timeout = p->timeout; |
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if (*parms[i]) |
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p->devs[i].timeout = *parms[i]; |
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|
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err = misc_register(&p->devs[i].misc); |
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if (err) { |
|
pr_err("Could not register misc device for dev %d\n", |
|
i); |
|
goto out_unregister; |
|
} |
|
} |
|
|
|
if (p->broken) { |
|
timer_setup(&cpwd_timer, cpwd_brokentimer, 0); |
|
cpwd_timer.expires = WD_BTIMEOUT; |
|
|
|
pr_info("PLD defect workaround enabled for model %s\n", |
|
WD_BADMODEL); |
|
} |
|
|
|
platform_set_drvdata(op, p); |
|
cpwd_device = p; |
|
return 0; |
|
|
|
out_unregister: |
|
for (i--; i >= 0; i--) |
|
misc_deregister(&p->devs[i].misc); |
|
|
|
out_iounmap: |
|
of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ); |
|
|
|
return err; |
|
} |
|
|
|
static int cpwd_remove(struct platform_device *op) |
|
{ |
|
struct cpwd *p = platform_get_drvdata(op); |
|
int i; |
|
|
|
for (i = 0; i < WD_NUMDEVS; i++) { |
|
misc_deregister(&p->devs[i].misc); |
|
|
|
if (!p->enabled) { |
|
cpwd_stoptimer(p, i); |
|
if (p->devs[i].runstatus & WD_STAT_BSTOP) |
|
cpwd_resetbrokentimer(p, i); |
|
} |
|
} |
|
|
|
if (p->broken) |
|
del_timer_sync(&cpwd_timer); |
|
|
|
if (p->initialized) |
|
free_irq(p->irq, p); |
|
|
|
of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ); |
|
|
|
cpwd_device = NULL; |
|
|
|
return 0; |
|
} |
|
|
|
static const struct of_device_id cpwd_match[] = { |
|
{ |
|
.name = "watchdog", |
|
}, |
|
{}, |
|
}; |
|
MODULE_DEVICE_TABLE(of, cpwd_match); |
|
|
|
static struct platform_driver cpwd_driver = { |
|
.driver = { |
|
.name = DRIVER_NAME, |
|
.of_match_table = cpwd_match, |
|
}, |
|
.probe = cpwd_probe, |
|
.remove = cpwd_remove, |
|
}; |
|
|
|
module_platform_driver(cpwd_driver);
|
|
|