12e62c498SMarcus Folkesson // SPDX-License-Identifier: GPL-2.0+ 2c283cf2cSMatteo Croce /* 3c283cf2cSMatteo Croce * drivers/watchdog/ar7_wdt.c 4c283cf2cSMatteo Croce * 5c283cf2cSMatteo Croce * Copyright (C) 2007 Nicolas Thill <nico@openwrt.org> 6c283cf2cSMatteo Croce * Copyright (c) 2005 Enrik Berkhan <Enrik.Berkhan@akk.org> 7c283cf2cSMatteo Croce * 8c283cf2cSMatteo Croce * Some code taken from: 9c283cf2cSMatteo Croce * National Semiconductor SCx200 Watchdog support 10c283cf2cSMatteo Croce * Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> 11c283cf2cSMatteo Croce * 12c283cf2cSMatteo Croce */ 13c283cf2cSMatteo Croce 1427c766aaSJoe Perches #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 1527c766aaSJoe Perches 16c283cf2cSMatteo Croce #include <linux/module.h> 17c283cf2cSMatteo Croce #include <linux/moduleparam.h> 18c283cf2cSMatteo Croce #include <linux/errno.h> 19c283cf2cSMatteo Croce #include <linux/miscdevice.h> 2064d4062aSFlorian Fainelli #include <linux/platform_device.h> 21c283cf2cSMatteo Croce #include <linux/watchdog.h> 22c283cf2cSMatteo Croce #include <linux/fs.h> 23c283cf2cSMatteo Croce #include <linux/ioport.h> 24c283cf2cSMatteo Croce #include <linux/io.h> 25c283cf2cSMatteo Croce #include <linux/uaccess.h> 26780019ddSFlorian Fainelli #include <linux/clk.h> 27c283cf2cSMatteo Croce 28c283cf2cSMatteo Croce #include <asm/addrspace.h> 29c5e7f5a3SFlorian Fainelli #include <asm/mach-ar7/ar7.h> 30c283cf2cSMatteo Croce 31c283cf2cSMatteo Croce #define LONGNAME "TI AR7 Watchdog Timer" 32c283cf2cSMatteo Croce 33c283cf2cSMatteo Croce MODULE_AUTHOR("Nicolas Thill <nico@openwrt.org>"); 34c283cf2cSMatteo Croce MODULE_DESCRIPTION(LONGNAME); 35c283cf2cSMatteo Croce MODULE_LICENSE("GPL"); 36c283cf2cSMatteo Croce 37c283cf2cSMatteo Croce static int margin = 60; 38c283cf2cSMatteo Croce module_param(margin, int, 0); 39c283cf2cSMatteo Croce MODULE_PARM_DESC(margin, "Watchdog margin in seconds"); 40c283cf2cSMatteo Croce 4186a1e189SWim Van Sebroeck static bool nowayout = WATCHDOG_NOWAYOUT; 4286a1e189SWim Van Sebroeck module_param(nowayout, bool, 0); 43c283cf2cSMatteo Croce MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close"); 44c283cf2cSMatteo Croce 45c283cf2cSMatteo Croce #define READ_REG(x) readl((void __iomem *)&(x)) 46c283cf2cSMatteo Croce #define WRITE_REG(x, v) writel((v), (void __iomem *)&(x)) 47c283cf2cSMatteo Croce 48c283cf2cSMatteo Croce struct ar7_wdt { 49c283cf2cSMatteo Croce u32 kick_lock; 50c283cf2cSMatteo Croce u32 kick; 51c283cf2cSMatteo Croce u32 change_lock; 52c283cf2cSMatteo Croce u32 change; 53c283cf2cSMatteo Croce u32 disable_lock; 54c283cf2cSMatteo Croce u32 disable; 55c283cf2cSMatteo Croce u32 prescale_lock; 56c283cf2cSMatteo Croce u32 prescale; 57c283cf2cSMatteo Croce }; 58c283cf2cSMatteo Croce 59670d59c0SAlan Cox static unsigned long wdt_is_open; 60c283cf2cSMatteo Croce static unsigned expect_close; 611334f329SAxel Lin static DEFINE_SPINLOCK(wdt_lock); 62c283cf2cSMatteo Croce 63c283cf2cSMatteo Croce /* XXX currently fixed, allows max margin ~68.72 secs */ 64c283cf2cSMatteo Croce #define prescale_value 0xffff 65c283cf2cSMatteo Croce 6664d4062aSFlorian Fainelli /* Resource of the WDT registers */ 6764d4062aSFlorian Fainelli static struct resource *ar7_regs_wdt; 68c283cf2cSMatteo Croce /* Pointer to the remapped WDT IO space */ 69c283cf2cSMatteo Croce static struct ar7_wdt *ar7_wdt; 70c283cf2cSMatteo Croce 71780019ddSFlorian Fainelli static struct clk *vbus_clk; 72780019ddSFlorian Fainelli 73c283cf2cSMatteo Croce static void ar7_wdt_kick(u32 value) 74c283cf2cSMatteo Croce { 75c283cf2cSMatteo Croce WRITE_REG(ar7_wdt->kick_lock, 0x5555); 76c283cf2cSMatteo Croce if ((READ_REG(ar7_wdt->kick_lock) & 3) == 1) { 77c283cf2cSMatteo Croce WRITE_REG(ar7_wdt->kick_lock, 0xaaaa); 78c283cf2cSMatteo Croce if ((READ_REG(ar7_wdt->kick_lock) & 3) == 3) { 79c283cf2cSMatteo Croce WRITE_REG(ar7_wdt->kick, value); 80c283cf2cSMatteo Croce return; 81c283cf2cSMatteo Croce } 82c283cf2cSMatteo Croce } 8327c766aaSJoe Perches pr_err("failed to unlock WDT kick reg\n"); 84c283cf2cSMatteo Croce } 85c283cf2cSMatteo Croce 86c283cf2cSMatteo Croce static void ar7_wdt_prescale(u32 value) 87c283cf2cSMatteo Croce { 88c283cf2cSMatteo Croce WRITE_REG(ar7_wdt->prescale_lock, 0x5a5a); 89c283cf2cSMatteo Croce if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 1) { 90c283cf2cSMatteo Croce WRITE_REG(ar7_wdt->prescale_lock, 0xa5a5); 91c283cf2cSMatteo Croce if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 3) { 92c283cf2cSMatteo Croce WRITE_REG(ar7_wdt->prescale, value); 93c283cf2cSMatteo Croce return; 94c283cf2cSMatteo Croce } 95c283cf2cSMatteo Croce } 9627c766aaSJoe Perches pr_err("failed to unlock WDT prescale reg\n"); 97c283cf2cSMatteo Croce } 98c283cf2cSMatteo Croce 99c283cf2cSMatteo Croce static void ar7_wdt_change(u32 value) 100c283cf2cSMatteo Croce { 101c283cf2cSMatteo Croce WRITE_REG(ar7_wdt->change_lock, 0x6666); 102c283cf2cSMatteo Croce if ((READ_REG(ar7_wdt->change_lock) & 3) == 1) { 103c283cf2cSMatteo Croce WRITE_REG(ar7_wdt->change_lock, 0xbbbb); 104c283cf2cSMatteo Croce if ((READ_REG(ar7_wdt->change_lock) & 3) == 3) { 105c283cf2cSMatteo Croce WRITE_REG(ar7_wdt->change, value); 106c283cf2cSMatteo Croce return; 107c283cf2cSMatteo Croce } 108c283cf2cSMatteo Croce } 10927c766aaSJoe Perches pr_err("failed to unlock WDT change reg\n"); 110c283cf2cSMatteo Croce } 111c283cf2cSMatteo Croce 112c283cf2cSMatteo Croce static void ar7_wdt_disable(u32 value) 113c283cf2cSMatteo Croce { 114c283cf2cSMatteo Croce WRITE_REG(ar7_wdt->disable_lock, 0x7777); 115c283cf2cSMatteo Croce if ((READ_REG(ar7_wdt->disable_lock) & 3) == 1) { 116c283cf2cSMatteo Croce WRITE_REG(ar7_wdt->disable_lock, 0xcccc); 117c283cf2cSMatteo Croce if ((READ_REG(ar7_wdt->disable_lock) & 3) == 2) { 118c283cf2cSMatteo Croce WRITE_REG(ar7_wdt->disable_lock, 0xdddd); 119c283cf2cSMatteo Croce if ((READ_REG(ar7_wdt->disable_lock) & 3) == 3) { 120c283cf2cSMatteo Croce WRITE_REG(ar7_wdt->disable, value); 121c283cf2cSMatteo Croce return; 122c283cf2cSMatteo Croce } 123c283cf2cSMatteo Croce } 124c283cf2cSMatteo Croce } 12527c766aaSJoe Perches pr_err("failed to unlock WDT disable reg\n"); 126c283cf2cSMatteo Croce } 127c283cf2cSMatteo Croce 128c283cf2cSMatteo Croce static void ar7_wdt_update_margin(int new_margin) 129c283cf2cSMatteo Croce { 130c283cf2cSMatteo Croce u32 change; 131780019ddSFlorian Fainelli u32 vbus_rate; 132c283cf2cSMatteo Croce 133780019ddSFlorian Fainelli vbus_rate = clk_get_rate(vbus_clk); 134780019ddSFlorian Fainelli change = new_margin * (vbus_rate / prescale_value); 135670d59c0SAlan Cox if (change < 1) 136670d59c0SAlan Cox change = 1; 137670d59c0SAlan Cox if (change > 0xffff) 138670d59c0SAlan Cox change = 0xffff; 139c283cf2cSMatteo Croce ar7_wdt_change(change); 140780019ddSFlorian Fainelli margin = change * prescale_value / vbus_rate; 14127c766aaSJoe Perches pr_info("timer margin %d seconds (prescale %d, change %d, freq %d)\n", 142780019ddSFlorian Fainelli margin, prescale_value, change, vbus_rate); 143c283cf2cSMatteo Croce } 144c283cf2cSMatteo Croce 145c283cf2cSMatteo Croce static void ar7_wdt_enable_wdt(void) 146c283cf2cSMatteo Croce { 14727c766aaSJoe Perches pr_debug("enabling watchdog timer\n"); 148c283cf2cSMatteo Croce ar7_wdt_disable(1); 149c283cf2cSMatteo Croce ar7_wdt_kick(1); 150c283cf2cSMatteo Croce } 151c283cf2cSMatteo Croce 152c283cf2cSMatteo Croce static void ar7_wdt_disable_wdt(void) 153c283cf2cSMatteo Croce { 15427c766aaSJoe Perches pr_debug("disabling watchdog timer\n"); 155c283cf2cSMatteo Croce ar7_wdt_disable(0); 156c283cf2cSMatteo Croce } 157c283cf2cSMatteo Croce 158c283cf2cSMatteo Croce static int ar7_wdt_open(struct inode *inode, struct file *file) 159c283cf2cSMatteo Croce { 160c283cf2cSMatteo Croce /* only allow one at a time */ 161670d59c0SAlan Cox if (test_and_set_bit(0, &wdt_is_open)) 162c283cf2cSMatteo Croce return -EBUSY; 163c283cf2cSMatteo Croce ar7_wdt_enable_wdt(); 164c283cf2cSMatteo Croce expect_close = 0; 165c283cf2cSMatteo Croce 166c283cf2cSMatteo Croce return nonseekable_open(inode, file); 167c283cf2cSMatteo Croce } 168c283cf2cSMatteo Croce 169c283cf2cSMatteo Croce static int ar7_wdt_release(struct inode *inode, struct file *file) 170c283cf2cSMatteo Croce { 171c283cf2cSMatteo Croce if (!expect_close) 17227c766aaSJoe Perches pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n"); 173c283cf2cSMatteo Croce else if (!nowayout) 174c283cf2cSMatteo Croce ar7_wdt_disable_wdt(); 175670d59c0SAlan Cox clear_bit(0, &wdt_is_open); 176c283cf2cSMatteo Croce return 0; 177c283cf2cSMatteo Croce } 178c283cf2cSMatteo Croce 179c283cf2cSMatteo Croce static ssize_t ar7_wdt_write(struct file *file, const char *data, 180c283cf2cSMatteo Croce size_t len, loff_t *ppos) 181c283cf2cSMatteo Croce { 182c283cf2cSMatteo Croce /* check for a magic close character */ 183c283cf2cSMatteo Croce if (len) { 184c283cf2cSMatteo Croce size_t i; 185c283cf2cSMatteo Croce 186670d59c0SAlan Cox spin_lock(&wdt_lock); 187c283cf2cSMatteo Croce ar7_wdt_kick(1); 188670d59c0SAlan Cox spin_unlock(&wdt_lock); 189c283cf2cSMatteo Croce 190c283cf2cSMatteo Croce expect_close = 0; 191c283cf2cSMatteo Croce for (i = 0; i < len; ++i) { 192c283cf2cSMatteo Croce char c; 193c283cf2cSMatteo Croce if (get_user(c, data + i)) 194c283cf2cSMatteo Croce return -EFAULT; 195c283cf2cSMatteo Croce if (c == 'V') 196c283cf2cSMatteo Croce expect_close = 1; 197c283cf2cSMatteo Croce } 198c283cf2cSMatteo Croce 199c283cf2cSMatteo Croce } 200c283cf2cSMatteo Croce return len; 201c283cf2cSMatteo Croce } 202c283cf2cSMatteo Croce 203670d59c0SAlan Cox static long ar7_wdt_ioctl(struct file *file, 204c283cf2cSMatteo Croce unsigned int cmd, unsigned long arg) 205c283cf2cSMatteo Croce { 20642747d71SWim Van Sebroeck static const struct watchdog_info ident = { 207c283cf2cSMatteo Croce .identity = LONGNAME, 208c283cf2cSMatteo Croce .firmware_version = 1, 209e73a7802SWim Van Sebroeck .options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | 210e73a7802SWim Van Sebroeck WDIOF_MAGICCLOSE), 211c283cf2cSMatteo Croce }; 212c283cf2cSMatteo Croce int new_margin; 213c283cf2cSMatteo Croce 214c283cf2cSMatteo Croce switch (cmd) { 215c283cf2cSMatteo Croce case WDIOC_GETSUPPORT: 216c283cf2cSMatteo Croce if (copy_to_user((struct watchdog_info *)arg, &ident, 217c283cf2cSMatteo Croce sizeof(ident))) 218c283cf2cSMatteo Croce return -EFAULT; 219c283cf2cSMatteo Croce return 0; 220c283cf2cSMatteo Croce case WDIOC_GETSTATUS: 221c283cf2cSMatteo Croce case WDIOC_GETBOOTSTATUS: 222c283cf2cSMatteo Croce if (put_user(0, (int *)arg)) 223c283cf2cSMatteo Croce return -EFAULT; 224c283cf2cSMatteo Croce return 0; 225c283cf2cSMatteo Croce case WDIOC_KEEPALIVE: 226c283cf2cSMatteo Croce ar7_wdt_kick(1); 227c283cf2cSMatteo Croce return 0; 228c283cf2cSMatteo Croce case WDIOC_SETTIMEOUT: 229c283cf2cSMatteo Croce if (get_user(new_margin, (int *)arg)) 230c283cf2cSMatteo Croce return -EFAULT; 231c283cf2cSMatteo Croce if (new_margin < 1) 232c283cf2cSMatteo Croce return -EINVAL; 233c283cf2cSMatteo Croce 234670d59c0SAlan Cox spin_lock(&wdt_lock); 235c283cf2cSMatteo Croce ar7_wdt_update_margin(new_margin); 236c283cf2cSMatteo Croce ar7_wdt_kick(1); 237670d59c0SAlan Cox spin_unlock(&wdt_lock); 238c283cf2cSMatteo Croce 239c283cf2cSMatteo Croce case WDIOC_GETTIMEOUT: 240c283cf2cSMatteo Croce if (put_user(margin, (int *)arg)) 241c283cf2cSMatteo Croce return -EFAULT; 242c283cf2cSMatteo Croce return 0; 2430c06090cSWim Van Sebroeck default: 2440c06090cSWim Van Sebroeck return -ENOTTY; 245c283cf2cSMatteo Croce } 246c283cf2cSMatteo Croce } 247c283cf2cSMatteo Croce 248b47a166eSJan Engelhardt static const struct file_operations ar7_wdt_fops = { 249c283cf2cSMatteo Croce .owner = THIS_MODULE, 250c283cf2cSMatteo Croce .write = ar7_wdt_write, 251670d59c0SAlan Cox .unlocked_ioctl = ar7_wdt_ioctl, 252c283cf2cSMatteo Croce .open = ar7_wdt_open, 253c283cf2cSMatteo Croce .release = ar7_wdt_release, 2546038f373SArnd Bergmann .llseek = no_llseek, 255c283cf2cSMatteo Croce }; 256c283cf2cSMatteo Croce 257c283cf2cSMatteo Croce static struct miscdevice ar7_wdt_miscdev = { 258c283cf2cSMatteo Croce .minor = WATCHDOG_MINOR, 259c283cf2cSMatteo Croce .name = "watchdog", 260c283cf2cSMatteo Croce .fops = &ar7_wdt_fops, 261c283cf2cSMatteo Croce }; 262c283cf2cSMatteo Croce 2632d991a16SBill Pemberton static int ar7_wdt_probe(struct platform_device *pdev) 264c283cf2cSMatteo Croce { 265c283cf2cSMatteo Croce int rc; 266c283cf2cSMatteo Croce 26764d4062aSFlorian Fainelli ar7_regs_wdt = 26864d4062aSFlorian Fainelli platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs"); 2694c271bb6SThierry Reding ar7_wdt = devm_ioremap_resource(&pdev->dev, ar7_regs_wdt); 2704c271bb6SThierry Reding if (IS_ERR(ar7_wdt)) 2714c271bb6SThierry Reding return PTR_ERR(ar7_wdt); 272c283cf2cSMatteo Croce 273780019ddSFlorian Fainelli vbus_clk = clk_get(NULL, "vbus"); 274780019ddSFlorian Fainelli if (IS_ERR(vbus_clk)) { 27527c766aaSJoe Perches pr_err("could not get vbus clock\n"); 276ae21cc20SJulia Lawall return PTR_ERR(vbus_clk); 277780019ddSFlorian Fainelli } 278780019ddSFlorian Fainelli 279c283cf2cSMatteo Croce ar7_wdt_disable_wdt(); 280c283cf2cSMatteo Croce ar7_wdt_prescale(prescale_value); 281c283cf2cSMatteo Croce ar7_wdt_update_margin(margin); 282c283cf2cSMatteo Croce 283c283cf2cSMatteo Croce rc = misc_register(&ar7_wdt_miscdev); 284c283cf2cSMatteo Croce if (rc) { 28527c766aaSJoe Perches pr_err("unable to register misc device\n"); 286c283cf2cSMatteo Croce goto out; 287ae21cc20SJulia Lawall } 288ae21cc20SJulia Lawall return 0; 289c283cf2cSMatteo Croce 290c283cf2cSMatteo Croce out: 291ae21cc20SJulia Lawall clk_put(vbus_clk); 292ae21cc20SJulia Lawall vbus_clk = NULL; 293c283cf2cSMatteo Croce return rc; 294c283cf2cSMatteo Croce } 295c283cf2cSMatteo Croce 2964b12b896SBill Pemberton static int ar7_wdt_remove(struct platform_device *pdev) 297c283cf2cSMatteo Croce { 298c283cf2cSMatteo Croce misc_deregister(&ar7_wdt_miscdev); 299ae21cc20SJulia Lawall clk_put(vbus_clk); 300ae21cc20SJulia Lawall vbus_clk = NULL; 30164d4062aSFlorian Fainelli return 0; 30264d4062aSFlorian Fainelli } 30364d4062aSFlorian Fainelli 30464d4062aSFlorian Fainelli static void ar7_wdt_shutdown(struct platform_device *pdev) 30564d4062aSFlorian Fainelli { 30664d4062aSFlorian Fainelli if (!nowayout) 30764d4062aSFlorian Fainelli ar7_wdt_disable_wdt(); 30864d4062aSFlorian Fainelli } 30964d4062aSFlorian Fainelli 31064d4062aSFlorian Fainelli static struct platform_driver ar7_wdt_driver = { 31164d4062aSFlorian Fainelli .probe = ar7_wdt_probe, 31282268714SBill Pemberton .remove = ar7_wdt_remove, 31364d4062aSFlorian Fainelli .shutdown = ar7_wdt_shutdown, 31464d4062aSFlorian Fainelli .driver = { 31564d4062aSFlorian Fainelli .name = "ar7_wdt", 31664d4062aSFlorian Fainelli }, 31764d4062aSFlorian Fainelli }; 31864d4062aSFlorian Fainelli 319b8ec6118SAxel Lin module_platform_driver(ar7_wdt_driver); 320