/* * sunxi Watchdog Driver * * Copyright (c) 2013 Carlo Caione * 2012 Henrik Nordstrom * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Based on xen_wdt.c * (c) Copyright 2010 Novell, Inc. */ #include <linux/clk.h> #include <linux/delay.h> #include <linux/err.h> #include <linux/init.h> #include <linux/io.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/of.h> #include <linux/of_device.h> #include <linux/platform_device.h> #include <linux/types.h> #include <linux/watchdog.h> #define WDT_MAX_TIMEOUT 16 #define WDT_MIN_TIMEOUT 1 #define WDT_TIMEOUT_MASK 0x0F #define WDT_CTRL_RELOAD ((1 << 0) | (0x0a57 << 1)) #define WDT_MODE_EN (1 << 0) #define DRV_NAME "sunxi-wdt" #define DRV_VERSION "1.0" static bool nowayout = WATCHDOG_NOWAYOUT; static unsigned int timeout = WDT_MAX_TIMEOUT; /* * This structure stores the register offsets for different variants * of Allwinner's watchdog hardware. */ struct sunxi_wdt_reg { u8 wdt_ctrl; u8 wdt_cfg; u8 wdt_mode; u8 wdt_timeout_shift; u8 wdt_reset_mask; u8 wdt_reset_val; }; struct sunxi_wdt_dev { struct watchdog_device wdt_dev; void __iomem *wdt_base; const struct sunxi_wdt_reg *wdt_regs; }; /* * wdt_timeout_map maps the watchdog timer interval value in seconds to * the value of the register WDT_MODE at bits .wdt_timeout_shift ~ +3 * * [timeout seconds] = register value * */ static const int wdt_timeout_map[] = { [1] = 0x1, /* 1s */ [2] = 0x2, /* 2s */ [3] = 0x3, /* 3s */ [4] = 0x4, /* 4s */ [5] = 0x5, /* 5s */ [6] = 0x6, /* 6s */ [8] = 0x7, /* 8s */ [10] = 0x8, /* 10s */ [12] = 0x9, /* 12s */ [14] = 0xA, /* 14s */ [16] = 0xB, /* 16s */ }; static int sunxi_wdt_restart(struct watchdog_device *wdt_dev, unsigned long action, void *data) { struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); void __iomem *wdt_base = sunxi_wdt->wdt_base; const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs; u32 val; /* Set system reset function */ val = readl(wdt_base + regs->wdt_cfg); val &= ~(regs->wdt_reset_mask); val |= regs->wdt_reset_val; writel(val, wdt_base + regs->wdt_cfg); /* Set lowest timeout and enable watchdog */ val = readl(wdt_base + regs->wdt_mode); val &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift); val |= WDT_MODE_EN; writel(val, wdt_base + regs->wdt_mode); /* * Restart the watchdog. The default (and lowest) interval * value for the watchdog is 0.5s. */ writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl); while (1) { mdelay(5); val = readl(wdt_base + regs->wdt_mode); val |= WDT_MODE_EN; writel(val, wdt_base + regs->wdt_mode); } return 0; } static int sunxi_wdt_ping(struct watchdog_device *wdt_dev) { struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); void __iomem *wdt_base = sunxi_wdt->wdt_base; const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs; writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl); return 0; } static int sunxi_wdt_set_timeout(struct watchdog_device *wdt_dev, unsigned int timeout) { struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); void __iomem *wdt_base = sunxi_wdt->wdt_base; const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs; u32 reg; if (wdt_timeout_map[timeout] == 0) timeout++; sunxi_wdt->wdt_dev.timeout = timeout; reg = readl(wdt_base + regs->wdt_mode); reg &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift); reg |= wdt_timeout_map[timeout] << regs->wdt_timeout_shift; writel(reg, wdt_base + regs->wdt_mode); sunxi_wdt_ping(wdt_dev); return 0; } static int sunxi_wdt_stop(struct watchdog_device *wdt_dev) { struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); void __iomem *wdt_base = sunxi_wdt->wdt_base; const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs; writel(0, wdt_base + regs->wdt_mode); return 0; } static int sunxi_wdt_start(struct watchdog_device *wdt_dev) { u32 reg; struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); void __iomem *wdt_base = sunxi_wdt->wdt_base; const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs; int ret; ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev, sunxi_wdt->wdt_dev.timeout); if (ret < 0) return ret; /* Set system reset function */ reg = readl(wdt_base + regs->wdt_cfg); reg &= ~(regs->wdt_reset_mask); reg |= regs->wdt_reset_val; writel(reg, wdt_base + regs->wdt_cfg); /* Enable watchdog */ reg = readl(wdt_base + regs->wdt_mode); reg |= WDT_MODE_EN; writel(reg, wdt_base + regs->wdt_mode); return 0; } static const struct watchdog_info sunxi_wdt_info = { .identity = DRV_NAME, .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, }; static const struct watchdog_ops sunxi_wdt_ops = { .owner = THIS_MODULE, .start = sunxi_wdt_start, .stop = sunxi_wdt_stop, .ping = sunxi_wdt_ping, .set_timeout = sunxi_wdt_set_timeout, .restart = sunxi_wdt_restart, }; static const struct sunxi_wdt_reg sun4i_wdt_reg = { .wdt_ctrl = 0x00, .wdt_cfg = 0x04, .wdt_mode = 0x04, .wdt_timeout_shift = 3, .wdt_reset_mask = 0x02, .wdt_reset_val = 0x02, }; static const struct sunxi_wdt_reg sun6i_wdt_reg = { .wdt_ctrl = 0x10, .wdt_cfg = 0x14, .wdt_mode = 0x18, .wdt_timeout_shift = 4, .wdt_reset_mask = 0x03, .wdt_reset_val = 0x01, }; static const struct of_device_id sunxi_wdt_dt_ids[] = { { .compatible = "allwinner,sun4i-a10-wdt", .data = &sun4i_wdt_reg }, { .compatible = "allwinner,sun6i-a31-wdt", .data = &sun6i_wdt_reg }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids); static int sunxi_wdt_probe(struct platform_device *pdev) { struct sunxi_wdt_dev *sunxi_wdt; const struct of_device_id *device; struct resource *res; int err; sunxi_wdt = devm_kzalloc(&pdev->dev, sizeof(*sunxi_wdt), GFP_KERNEL); if (!sunxi_wdt) return -EINVAL; device = of_match_device(sunxi_wdt_dt_ids, &pdev->dev); if (!device) return -ENODEV; sunxi_wdt->wdt_regs = device->data; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); sunxi_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(sunxi_wdt->wdt_base)) return PTR_ERR(sunxi_wdt->wdt_base); sunxi_wdt->wdt_dev.info = &sunxi_wdt_info; sunxi_wdt->wdt_dev.ops = &sunxi_wdt_ops; sunxi_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT; sunxi_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT; sunxi_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT; sunxi_wdt->wdt_dev.parent = &pdev->dev; watchdog_init_timeout(&sunxi_wdt->wdt_dev, timeout, &pdev->dev); watchdog_set_nowayout(&sunxi_wdt->wdt_dev, nowayout); watchdog_set_restart_priority(&sunxi_wdt->wdt_dev, 128); watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt); sunxi_wdt_stop(&sunxi_wdt->wdt_dev); watchdog_stop_on_reboot(&sunxi_wdt->wdt_dev); err = devm_watchdog_register_device(&pdev->dev, &sunxi_wdt->wdt_dev); if (unlikely(err)) return err; dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)", sunxi_wdt->wdt_dev.timeout, nowayout); return 0; } static struct platform_driver sunxi_wdt_driver = { .probe = sunxi_wdt_probe, .driver = { .name = DRV_NAME, .of_match_table = sunxi_wdt_dt_ids, }, }; module_platform_driver(sunxi_wdt_driver); module_param(timeout, uint, 0); MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds"); module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>"); MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>"); MODULE_DESCRIPTION("sunxi WatchDog Timer Driver"); MODULE_VERSION(DRV_VERSION);