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317 lines
7.4 KiB
317 lines
7.4 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Intel Atom E6xx Watchdog driver |
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* |
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* Copyright (C) 2011 Alexander Stein |
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* <[email protected]> |
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*/ |
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#include <linux/module.h> |
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#include <linux/moduleparam.h> |
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#include <linux/platform_device.h> |
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#include <linux/io.h> |
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#include <linux/kernel.h> |
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#include <linux/types.h> |
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#include <linux/watchdog.h> |
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#include <linux/seq_file.h> |
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#include <linux/debugfs.h> |
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#include <linux/uaccess.h> |
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#include <linux/spinlock.h> |
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#define DRIVER_NAME "ie6xx_wdt" |
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#define PV1 0x00 |
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#define PV2 0x04 |
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#define RR0 0x0c |
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#define RR1 0x0d |
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#define WDT_RELOAD 0x01 |
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#define WDT_TOUT 0x02 |
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#define WDTCR 0x10 |
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#define WDT_PRE_SEL 0x04 |
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#define WDT_RESET_SEL 0x08 |
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#define WDT_RESET_EN 0x10 |
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#define WDT_TOUT_EN 0x20 |
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#define DCR 0x14 |
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#define WDTLR 0x18 |
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#define WDT_LOCK 0x01 |
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#define WDT_ENABLE 0x02 |
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#define WDT_TOUT_CNF 0x03 |
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#define MIN_TIME 1 |
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#define MAX_TIME (10 * 60) /* 10 minutes */ |
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#define DEFAULT_TIME 60 |
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static unsigned int timeout = DEFAULT_TIME; |
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module_param(timeout, uint, 0); |
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MODULE_PARM_DESC(timeout, |
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"Default Watchdog timer setting (" |
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__MODULE_STRING(DEFAULT_TIME) "s)." |
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"The range is from 1 to 600"); |
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static bool nowayout = WATCHDOG_NOWAYOUT; |
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module_param(nowayout, bool, 0); |
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MODULE_PARM_DESC(nowayout, |
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"Watchdog cannot be stopped once started (default=" |
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
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static u8 resetmode = 0x10; |
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module_param(resetmode, byte, 0); |
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MODULE_PARM_DESC(resetmode, |
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"Resetmode bits: 0x08 warm reset (cold reset otherwise), " |
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"0x10 reset enable, 0x20 disable toggle GPIO[4] (default=0x10)"); |
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static struct { |
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unsigned short sch_wdtba; |
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spinlock_t unlock_sequence; |
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#ifdef CONFIG_DEBUG_FS |
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struct dentry *debugfs; |
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#endif |
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} ie6xx_wdt_data; |
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/* |
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* This is needed to write to preload and reload registers |
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* struct ie6xx_wdt_data.unlock_sequence must be used |
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* to prevent sequence interrupts |
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*/ |
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static void ie6xx_wdt_unlock_registers(void) |
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{ |
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outb(0x80, ie6xx_wdt_data.sch_wdtba + RR0); |
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outb(0x86, ie6xx_wdt_data.sch_wdtba + RR0); |
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} |
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static int ie6xx_wdt_ping(struct watchdog_device *wdd) |
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{ |
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spin_lock(&ie6xx_wdt_data.unlock_sequence); |
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ie6xx_wdt_unlock_registers(); |
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outb(WDT_RELOAD, ie6xx_wdt_data.sch_wdtba + RR1); |
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spin_unlock(&ie6xx_wdt_data.unlock_sequence); |
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return 0; |
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} |
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static int ie6xx_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t) |
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{ |
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u32 preload; |
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u64 clock; |
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u8 wdtcr; |
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/* Watchdog clock is PCI Clock (33MHz) */ |
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clock = 33000000; |
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/* and the preload value is loaded into [34:15] of the down counter */ |
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preload = (t * clock) >> 15; |
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/* |
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* Manual states preload must be one less. |
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* Does not wrap as t is at least 1 |
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*/ |
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preload -= 1; |
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spin_lock(&ie6xx_wdt_data.unlock_sequence); |
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/* Set ResetMode & Enable prescaler for range 10ms to 10 min */ |
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wdtcr = resetmode & 0x38; |
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outb(wdtcr, ie6xx_wdt_data.sch_wdtba + WDTCR); |
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ie6xx_wdt_unlock_registers(); |
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outl(0, ie6xx_wdt_data.sch_wdtba + PV1); |
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ie6xx_wdt_unlock_registers(); |
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outl(preload, ie6xx_wdt_data.sch_wdtba + PV2); |
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ie6xx_wdt_unlock_registers(); |
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outb(WDT_RELOAD | WDT_TOUT, ie6xx_wdt_data.sch_wdtba + RR1); |
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spin_unlock(&ie6xx_wdt_data.unlock_sequence); |
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wdd->timeout = t; |
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return 0; |
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} |
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static int ie6xx_wdt_start(struct watchdog_device *wdd) |
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{ |
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ie6xx_wdt_set_timeout(wdd, wdd->timeout); |
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/* Enable the watchdog timer */ |
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spin_lock(&ie6xx_wdt_data.unlock_sequence); |
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outb(WDT_ENABLE, ie6xx_wdt_data.sch_wdtba + WDTLR); |
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spin_unlock(&ie6xx_wdt_data.unlock_sequence); |
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return 0; |
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} |
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static int ie6xx_wdt_stop(struct watchdog_device *wdd) |
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{ |
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if (inb(ie6xx_wdt_data.sch_wdtba + WDTLR) & WDT_LOCK) |
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return -1; |
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/* Disable the watchdog timer */ |
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spin_lock(&ie6xx_wdt_data.unlock_sequence); |
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outb(0, ie6xx_wdt_data.sch_wdtba + WDTLR); |
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spin_unlock(&ie6xx_wdt_data.unlock_sequence); |
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return 0; |
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} |
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static const struct watchdog_info ie6xx_wdt_info = { |
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.identity = "Intel Atom E6xx Watchdog", |
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.options = WDIOF_SETTIMEOUT | |
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WDIOF_MAGICCLOSE | |
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WDIOF_KEEPALIVEPING, |
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}; |
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static const struct watchdog_ops ie6xx_wdt_ops = { |
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.owner = THIS_MODULE, |
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.start = ie6xx_wdt_start, |
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.stop = ie6xx_wdt_stop, |
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.ping = ie6xx_wdt_ping, |
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.set_timeout = ie6xx_wdt_set_timeout, |
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}; |
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static struct watchdog_device ie6xx_wdt_dev = { |
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.info = &ie6xx_wdt_info, |
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.ops = &ie6xx_wdt_ops, |
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.min_timeout = MIN_TIME, |
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.max_timeout = MAX_TIME, |
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}; |
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#ifdef CONFIG_DEBUG_FS |
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static int ie6xx_wdt_show(struct seq_file *s, void *unused) |
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{ |
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seq_printf(s, "PV1 = 0x%08x\n", |
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inl(ie6xx_wdt_data.sch_wdtba + PV1)); |
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seq_printf(s, "PV2 = 0x%08x\n", |
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inl(ie6xx_wdt_data.sch_wdtba + PV2)); |
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seq_printf(s, "RR = 0x%08x\n", |
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inw(ie6xx_wdt_data.sch_wdtba + RR0)); |
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seq_printf(s, "WDTCR = 0x%08x\n", |
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inw(ie6xx_wdt_data.sch_wdtba + WDTCR)); |
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seq_printf(s, "DCR = 0x%08x\n", |
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inl(ie6xx_wdt_data.sch_wdtba + DCR)); |
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seq_printf(s, "WDTLR = 0x%08x\n", |
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inw(ie6xx_wdt_data.sch_wdtba + WDTLR)); |
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seq_printf(s, "\n"); |
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return 0; |
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} |
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DEFINE_SHOW_ATTRIBUTE(ie6xx_wdt); |
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static void ie6xx_wdt_debugfs_init(void) |
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{ |
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/* /sys/kernel/debug/ie6xx_wdt */ |
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ie6xx_wdt_data.debugfs = debugfs_create_file("ie6xx_wdt", |
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S_IFREG | S_IRUGO, NULL, NULL, &ie6xx_wdt_fops); |
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} |
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static void ie6xx_wdt_debugfs_exit(void) |
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{ |
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debugfs_remove(ie6xx_wdt_data.debugfs); |
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} |
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#else |
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static void ie6xx_wdt_debugfs_init(void) |
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{ |
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} |
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static void ie6xx_wdt_debugfs_exit(void) |
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{ |
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} |
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#endif |
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static int ie6xx_wdt_probe(struct platform_device *pdev) |
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{ |
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struct resource *res; |
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u8 wdtlr; |
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int ret; |
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res = platform_get_resource(pdev, IORESOURCE_IO, 0); |
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if (!res) |
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return -ENODEV; |
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if (!request_region(res->start, resource_size(res), pdev->name)) { |
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dev_err(&pdev->dev, "Watchdog region 0x%llx already in use!\n", |
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(u64)res->start); |
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return -EBUSY; |
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} |
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ie6xx_wdt_data.sch_wdtba = res->start; |
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dev_dbg(&pdev->dev, "WDT = 0x%X\n", ie6xx_wdt_data.sch_wdtba); |
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ie6xx_wdt_dev.timeout = timeout; |
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watchdog_set_nowayout(&ie6xx_wdt_dev, nowayout); |
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ie6xx_wdt_dev.parent = &pdev->dev; |
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spin_lock_init(&ie6xx_wdt_data.unlock_sequence); |
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wdtlr = inb(ie6xx_wdt_data.sch_wdtba + WDTLR); |
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if (wdtlr & WDT_LOCK) |
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dev_warn(&pdev->dev, |
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"Watchdog Timer is Locked (Reg=0x%x)\n", wdtlr); |
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ie6xx_wdt_debugfs_init(); |
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ret = watchdog_register_device(&ie6xx_wdt_dev); |
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if (ret) |
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goto misc_register_error; |
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return 0; |
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misc_register_error: |
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ie6xx_wdt_debugfs_exit(); |
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release_region(res->start, resource_size(res)); |
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ie6xx_wdt_data.sch_wdtba = 0; |
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return ret; |
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} |
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static int ie6xx_wdt_remove(struct platform_device *pdev) |
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{ |
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struct resource *res; |
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res = platform_get_resource(pdev, IORESOURCE_IO, 0); |
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ie6xx_wdt_stop(NULL); |
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watchdog_unregister_device(&ie6xx_wdt_dev); |
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ie6xx_wdt_debugfs_exit(); |
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release_region(res->start, resource_size(res)); |
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ie6xx_wdt_data.sch_wdtba = 0; |
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return 0; |
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} |
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static struct platform_driver ie6xx_wdt_driver = { |
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.probe = ie6xx_wdt_probe, |
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.remove = ie6xx_wdt_remove, |
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.driver = { |
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.name = DRIVER_NAME, |
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}, |
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}; |
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static int __init ie6xx_wdt_init(void) |
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{ |
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/* Check boot parameters to verify that their initial values */ |
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/* are in range. */ |
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if ((timeout < MIN_TIME) || |
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(timeout > MAX_TIME)) { |
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pr_err("Watchdog timer: value of timeout %d (dec) " |
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"is out of range from %d to %d (dec)\n", |
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timeout, MIN_TIME, MAX_TIME); |
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return -EINVAL; |
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} |
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return platform_driver_register(&ie6xx_wdt_driver); |
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} |
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static void __exit ie6xx_wdt_exit(void) |
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{ |
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platform_driver_unregister(&ie6xx_wdt_driver); |
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} |
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late_initcall(ie6xx_wdt_init); |
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module_exit(ie6xx_wdt_exit); |
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MODULE_AUTHOR("Alexander Stein <[email protected]>"); |
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MODULE_DESCRIPTION("Intel Atom E6xx Watchdog Device Driver"); |
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MODULE_LICENSE("GPL"); |
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MODULE_ALIAS("platform:" DRIVER_NAME);
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