347 lines
8.6 KiB
C
347 lines
8.6 KiB
C
/*
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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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* <alexander.stein@systec-electronic.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General
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* Public License as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be
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* useful, but WITHOUT ANY WARRANTY; without even the implied
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* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* PURPOSE. See the GNU General Public License for more details.
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the Free
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* Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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* The full GNU General Public License is included in this
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* distribution in the file called COPYING.
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*
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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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struct spinlock 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_dbg_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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static int ie6xx_wdt_dbg_open(struct inode *inode, struct file *file)
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{
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return single_open(file, ie6xx_wdt_dbg_show, NULL);
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}
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static const struct file_operations ie6xx_wdt_dbg_operations = {
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.open = ie6xx_wdt_dbg_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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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_dbg_operations);
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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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dev_err(&pdev->dev,
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"Watchdog timer: cannot register device (err =%d)\n",
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ret);
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goto misc_register_error;
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}
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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 <alexander.stein@systec-electronic.com>");
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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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