diff options
Diffstat (limited to 'drivers/watchdog/ixp4xx_wdt.c')
| -rw-r--r-- | drivers/watchdog/ixp4xx_wdt.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/drivers/watchdog/ixp4xx_wdt.c b/drivers/watchdog/ixp4xx_wdt.c new file mode 100644 index 0000000000..ec0c08652e --- /dev/null +++ b/drivers/watchdog/ixp4xx_wdt.c @@ -0,0 +1,197 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * drivers/char/watchdog/ixp4xx_wdt.c + * + * Watchdog driver for Intel IXP4xx network processors + * + * Author: Deepak Saxena <dsaxena@plexity.net> + * Author: Linus Walleij <linus.walleij@linaro.org> + * + * Copyright 2004 (c) MontaVista, Software, Inc. + * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu> + */ + +#include <linux/module.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/watchdog.h> +#include <linux/bits.h> +#include <linux/platform_device.h> +#include <linux/clk.h> +#include <linux/soc/ixp4xx/cpu.h> + +struct ixp4xx_wdt { + struct watchdog_device wdd; + void __iomem *base; + unsigned long rate; +}; + +/* Fallback if we do not have a clock for this */ +#define IXP4XX_TIMER_FREQ 66666000 + +/* Registers after the timer registers */ +#define IXP4XX_OSWT_OFFSET 0x14 /* Watchdog Timer */ +#define IXP4XX_OSWE_OFFSET 0x18 /* Watchdog Enable */ +#define IXP4XX_OSWK_OFFSET 0x1C /* Watchdog Key */ +#define IXP4XX_OSST_OFFSET 0x20 /* Timer Status */ + +#define IXP4XX_OSST_TIMER_WDOG_PEND 0x00000008 +#define IXP4XX_OSST_TIMER_WARM_RESET 0x00000010 +#define IXP4XX_WDT_KEY 0x0000482E +#define IXP4XX_WDT_RESET_ENABLE 0x00000001 +#define IXP4XX_WDT_IRQ_ENABLE 0x00000002 +#define IXP4XX_WDT_COUNT_ENABLE 0x00000004 + +static inline +struct ixp4xx_wdt *to_ixp4xx_wdt(struct watchdog_device *wdd) +{ + return container_of(wdd, struct ixp4xx_wdt, wdd); +} + +static int ixp4xx_wdt_start(struct watchdog_device *wdd) +{ + struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd); + + __raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET); + __raw_writel(0, iwdt->base + IXP4XX_OSWE_OFFSET); + __raw_writel(wdd->timeout * iwdt->rate, + iwdt->base + IXP4XX_OSWT_OFFSET); + __raw_writel(IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE, + iwdt->base + IXP4XX_OSWE_OFFSET); + __raw_writel(0, iwdt->base + IXP4XX_OSWK_OFFSET); + + return 0; +} + +static int ixp4xx_wdt_stop(struct watchdog_device *wdd) +{ + struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd); + + __raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET); + __raw_writel(0, iwdt->base + IXP4XX_OSWE_OFFSET); + __raw_writel(0, iwdt->base + IXP4XX_OSWK_OFFSET); + + return 0; +} + +static int ixp4xx_wdt_set_timeout(struct watchdog_device *wdd, + unsigned int timeout) +{ + wdd->timeout = timeout; + if (watchdog_active(wdd)) + ixp4xx_wdt_start(wdd); + + return 0; +} + +static int ixp4xx_wdt_restart(struct watchdog_device *wdd, + unsigned long action, void *data) +{ + struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd); + + __raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET); + __raw_writel(0, iwdt->base + IXP4XX_OSWT_OFFSET); + __raw_writel(IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE, + iwdt->base + IXP4XX_OSWE_OFFSET); + + return 0; +} + +static const struct watchdog_ops ixp4xx_wdt_ops = { + .start = ixp4xx_wdt_start, + .stop = ixp4xx_wdt_stop, + .set_timeout = ixp4xx_wdt_set_timeout, + .restart = ixp4xx_wdt_restart, + .owner = THIS_MODULE, +}; + +/* + * The A0 version of the IXP422 had a bug in the watchdog making + * is useless, but we still need to use it to restart the system + * as it is the only way, so in this special case we register a + * "dummy" watchdog that doesn't really work, but will support + * the restart operation. + */ +static int ixp4xx_wdt_dummy(struct watchdog_device *wdd) +{ + return 0; +} + +static const struct watchdog_ops ixp4xx_wdt_restart_only_ops = { + .start = ixp4xx_wdt_dummy, + .stop = ixp4xx_wdt_dummy, + .restart = ixp4xx_wdt_restart, + .owner = THIS_MODULE, +}; + +static const struct watchdog_info ixp4xx_wdt_info = { + .options = WDIOF_KEEPALIVEPING + | WDIOF_MAGICCLOSE + | WDIOF_SETTIMEOUT, + .identity = KBUILD_MODNAME, +}; + +static int ixp4xx_wdt_probe(struct platform_device *pdev) +{ + static const struct watchdog_ops *iwdt_ops; + struct device *dev = &pdev->dev; + struct ixp4xx_wdt *iwdt; + struct clk *clk; + int ret; + + if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) { + dev_info(dev, "Rev. A0 IXP42x CPU detected - only restart supported\n"); + iwdt_ops = &ixp4xx_wdt_restart_only_ops; + } else { + iwdt_ops = &ixp4xx_wdt_ops; + } + + iwdt = devm_kzalloc(dev, sizeof(*iwdt), GFP_KERNEL); + if (!iwdt) + return -ENOMEM; + iwdt->base = (void __iomem *)dev->platform_data; + + /* + * Retrieve rate from a fixed clock from the device tree if + * the parent has that, else use the default clock rate. + */ + clk = devm_clk_get_enabled(dev->parent, NULL); + if (!IS_ERR(clk)) + iwdt->rate = clk_get_rate(clk); + + if (!iwdt->rate) + iwdt->rate = IXP4XX_TIMER_FREQ; + + iwdt->wdd.info = &ixp4xx_wdt_info; + iwdt->wdd.ops = iwdt_ops; + iwdt->wdd.min_timeout = 1; + iwdt->wdd.max_timeout = U32_MAX / iwdt->rate; + iwdt->wdd.parent = dev; + /* Default to 60 seconds */ + iwdt->wdd.timeout = 60U; + watchdog_init_timeout(&iwdt->wdd, 0, dev); + + if (__raw_readl(iwdt->base + IXP4XX_OSST_OFFSET) & + IXP4XX_OSST_TIMER_WARM_RESET) + iwdt->wdd.bootstatus = WDIOF_CARDRESET; + + ret = devm_watchdog_register_device(dev, &iwdt->wdd); + if (ret) + return ret; + + dev_info(dev, "IXP4xx watchdog available\n"); + + return 0; +} + +static struct platform_driver ixp4xx_wdt_driver = { + .probe = ixp4xx_wdt_probe, + .driver = { + .name = "ixp4xx-watchdog", + }, +}; +module_platform_driver(ixp4xx_wdt_driver); + +MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>"); +MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog"); +MODULE_LICENSE("GPL"); |