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1// SPDX-License-Identifier: GPL-2.0+2/*3 * Watchdog driver for the SA11x0/PXA2xx4 *5 * (c) Copyright 2000 Oleg Drokin <green@crimea.edu>6 * Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk>7 *8 * Neither Oleg Drokin nor iXcelerator.com admit liability nor provide9 * warranty for any of this software. This material is provided10 * "AS-IS" and at no charge.11 *12 * (c) Copyright 2000 Oleg Drokin <green@crimea.edu>13 *14 * 27/11/2000 Initial release15 */16 17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt18 19#include <linux/module.h>20#include <linux/moduleparam.h>21#include <linux/clk.h>22#include <linux/types.h>23#include <linux/kernel.h>24#include <linux/fs.h>25#include <linux/platform_device.h>26#include <linux/miscdevice.h>27#include <linux/watchdog.h>28#include <linux/init.h>29#include <linux/io.h>30#include <linux/bitops.h>31#include <linux/uaccess.h>32#include <linux/timex.h>33 34#define REG_OSMR0 0x0000 /* OS timer Match Reg. 0 */35#define REG_OSMR1 0x0004 /* OS timer Match Reg. 1 */36#define REG_OSMR2 0x0008 /* OS timer Match Reg. 2 */37#define REG_OSMR3 0x000c /* OS timer Match Reg. 3 */38#define REG_OSCR 0x0010 /* OS timer Counter Reg. */39#define REG_OSSR 0x0014 /* OS timer Status Reg. */40#define REG_OWER 0x0018 /* OS timer Watch-dog Enable Reg. */41#define REG_OIER 0x001C /* OS timer Interrupt Enable Reg. */42 43#define OSSR_M3 (1 << 3) /* Match status channel 3 */44#define OSSR_M2 (1 << 2) /* Match status channel 2 */45#define OSSR_M1 (1 << 1) /* Match status channel 1 */46#define OSSR_M0 (1 << 0) /* Match status channel 0 */47 48#define OWER_WME (1 << 0) /* Watchdog Match Enable */49 50#define OIER_E3 (1 << 3) /* Interrupt enable channel 3 */51#define OIER_E2 (1 << 2) /* Interrupt enable channel 2 */52#define OIER_E1 (1 << 1) /* Interrupt enable channel 1 */53#define OIER_E0 (1 << 0) /* Interrupt enable channel 0 */54 55static unsigned long oscr_freq;56static unsigned long sa1100wdt_users;57static unsigned int pre_margin;58static int boot_status;59static void __iomem *reg_base;60 61static inline void sa1100_wr(u32 val, u32 offset)62{63 writel_relaxed(val, reg_base + offset);64}65 66static inline u32 sa1100_rd(u32 offset)67{68 return readl_relaxed(reg_base + offset);69}70 71/*72 * Allow only one person to hold it open73 */74static int sa1100dog_open(struct inode *inode, struct file *file)75{76 if (test_and_set_bit(1, &sa1100wdt_users))77 return -EBUSY;78 79 /* Activate SA1100 Watchdog timer */80 sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_OSMR3);81 sa1100_wr(OSSR_M3, REG_OSSR);82 sa1100_wr(OWER_WME, REG_OWER);83 sa1100_wr(sa1100_rd(REG_OIER) | OIER_E3, REG_OIER);84 return stream_open(inode, file);85}86 87/*88 * The watchdog cannot be disabled.89 *90 * Previous comments suggested that turning off the interrupt by91 * clearing REG_OIER[E3] would prevent the watchdog timing out but this92 * does not appear to be true (at least on the PXA255).93 */94static int sa1100dog_release(struct inode *inode, struct file *file)95{96 pr_crit("Device closed - timer will not stop\n");97 clear_bit(1, &sa1100wdt_users);98 return 0;99}100 101static ssize_t sa1100dog_write(struct file *file, const char __user *data,102 size_t len, loff_t *ppos)103{104 if (len)105 /* Refresh OSMR3 timer. */106 sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_OSMR3);107 return len;108}109 110static const struct watchdog_info ident = {111 .options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT112 | WDIOF_KEEPALIVEPING,113 .identity = "SA1100/PXA255 Watchdog",114 .firmware_version = 1,115};116 117static long sa1100dog_ioctl(struct file *file, unsigned int cmd,118 unsigned long arg)119{120 int ret = -ENOTTY;121 int time;122 void __user *argp = (void __user *)arg;123 int __user *p = argp;124 125 switch (cmd) {126 case WDIOC_GETSUPPORT:127 ret = copy_to_user(argp, &ident,128 sizeof(ident)) ? -EFAULT : 0;129 break;130 131 case WDIOC_GETSTATUS:132 ret = put_user(0, p);133 break;134 135 case WDIOC_GETBOOTSTATUS:136 ret = put_user(boot_status, p);137 break;138 139 case WDIOC_KEEPALIVE:140 sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_OSMR3);141 ret = 0;142 break;143 144 case WDIOC_SETTIMEOUT:145 ret = get_user(time, p);146 if (ret)147 break;148 149 if (time <= 0 || (oscr_freq * (long long)time >= 0xffffffff)) {150 ret = -EINVAL;151 break;152 }153 154 pre_margin = oscr_freq * time;155 sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_OSMR3);156 fallthrough;157 158 case WDIOC_GETTIMEOUT:159 ret = put_user(pre_margin / oscr_freq, p);160 break;161 }162 return ret;163}164 165static const struct file_operations sa1100dog_fops = {166 .owner = THIS_MODULE,167 .write = sa1100dog_write,168 .unlocked_ioctl = sa1100dog_ioctl,169 .compat_ioctl = compat_ptr_ioctl,170 .open = sa1100dog_open,171 .release = sa1100dog_release,172};173 174static struct miscdevice sa1100dog_miscdev = {175 .minor = WATCHDOG_MINOR,176 .name = "watchdog",177 .fops = &sa1100dog_fops,178};179 180static int margin = 60; /* (secs) Default is 1 minute */181static struct clk *clk;182 183static int sa1100dog_probe(struct platform_device *pdev)184{185 int ret;186 int *platform_data;187 struct resource *res;188 189 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);190 if (!res)191 return -ENXIO;192 reg_base = devm_ioremap(&pdev->dev, res->start, resource_size(res));193 if (!reg_base)194 return -ENOMEM;195 196 clk = clk_get(NULL, "OSTIMER0");197 if (IS_ERR(clk)) {198 pr_err("SA1100/PXA2xx Watchdog Timer: clock not found: %d\n",199 (int) PTR_ERR(clk));200 return PTR_ERR(clk);201 }202 203 ret = clk_prepare_enable(clk);204 if (ret) {205 pr_err("SA1100/PXA2xx Watchdog Timer: clock failed to prepare+enable: %d\n",206 ret);207 goto err;208 }209 210 oscr_freq = clk_get_rate(clk);211 212 platform_data = pdev->dev.platform_data;213 if (platform_data && *platform_data)214 boot_status = WDIOF_CARDRESET;215 pre_margin = oscr_freq * margin;216 217 ret = misc_register(&sa1100dog_miscdev);218 if (ret == 0) {219 pr_info("SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n",220 margin);221 return 0;222 }223 224 clk_disable_unprepare(clk);225err:226 clk_put(clk);227 return ret;228}229 230static void sa1100dog_remove(struct platform_device *pdev)231{232 misc_deregister(&sa1100dog_miscdev);233 clk_disable_unprepare(clk);234 clk_put(clk);235}236 237static struct platform_driver sa1100dog_driver = {238 .driver.name = "sa1100_wdt",239 .probe = sa1100dog_probe,240 .remove_new = sa1100dog_remove,241};242module_platform_driver(sa1100dog_driver);243 244MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>");245MODULE_DESCRIPTION("SA1100/PXA2xx Watchdog");246 247module_param(margin, int, 0);248MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");249 250MODULE_LICENSE("GPL");251