diff options
Diffstat (limited to 'drivers/watchdog/bcm2835_wdt.c')
| -rw-r--r-- | drivers/watchdog/bcm2835_wdt.c | 160 |
1 files changed, 109 insertions, 51 deletions
diff --git a/drivers/watchdog/bcm2835_wdt.c b/drivers/watchdog/bcm2835_wdt.c index 61566fc47f84..9fcfee63905b 100644 --- a/drivers/watchdog/bcm2835_wdt.c +++ b/drivers/watchdog/bcm2835_wdt.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0+ /* * Watchdog driver for Broadcom BCM2835 * @@ -7,42 +8,61 @@ * * Copyright (C) 2013 Lubomir Rintel <lkundrak@v3.sk> * - * 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. */ +#include <linux/delay.h> #include <linux/types.h> +#include <linux/mfd/bcm2835-pm.h> #include <linux/module.h> #include <linux/io.h> #include <linux/watchdog.h> #include <linux/platform_device.h> #include <linux/of_address.h> -#include <linux/miscdevice.h> +#include <linux/of_platform.h> #define PM_RSTC 0x1c +#define PM_RSTS 0x20 #define PM_WDOG 0x24 #define PM_PASSWORD 0x5a000000 #define PM_WDOG_TIME_SET 0x000fffff #define PM_RSTC_WRCFG_CLR 0xffffffcf +#define PM_RSTS_HADWRH_SET 0x00000040 #define PM_RSTC_WRCFG_SET 0x00000030 #define PM_RSTC_WRCFG_FULL_RESET 0x00000020 #define PM_RSTC_RESET 0x00000102 +/* + * The Raspberry Pi firmware uses the RSTS register to know which partition + * to boot from. The partition value is spread into bits 0, 2, 4, 6, 8, 10. + * Partition 63 is a special partition used by the firmware to indicate halt. + */ +#define PM_RSTS_RASPBERRYPI_HALT 0x555 + #define SECS_TO_WDOG_TICKS(x) ((x) << 16) #define WDOG_TICKS_TO_SECS(x) ((x) >> 16) +#define WDOG_TICKS_TO_MSECS(x) ((x) * 1000 >> 16) struct bcm2835_wdt { void __iomem *base; spinlock_t lock; }; +static struct bcm2835_wdt *bcm2835_power_off_wdt; + static unsigned int heartbeat; static bool nowayout = WATCHDOG_NOWAYOUT; +static bool bcm2835_wdt_is_running(struct bcm2835_wdt *wdt) +{ + uint32_t cur; + + cur = readl(wdt->base + PM_RSTC); + + return !!(cur & PM_RSTC_WRCFG_FULL_RESET); +} + static int bcm2835_wdt_start(struct watchdog_device *wdog) { struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog); @@ -67,13 +87,6 @@ static int bcm2835_wdt_stop(struct watchdog_device *wdog) struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog); writel_relaxed(PM_PASSWORD | PM_RSTC_RESET, wdt->base + PM_RSTC); - dev_info(wdog->dev, "Watchdog timer stopped"); - return 0; -} - -static int bcm2835_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t) -{ - wdog->timeout = t; return 0; } @@ -85,15 +98,40 @@ static unsigned int bcm2835_wdt_get_timeleft(struct watchdog_device *wdog) return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET); } -static struct watchdog_ops bcm2835_wdt_ops = { +static void __bcm2835_restart(struct bcm2835_wdt *wdt) +{ + u32 val; + + /* use a timeout of 10 ticks (~150us) */ + writel_relaxed(10 | PM_PASSWORD, wdt->base + PM_WDOG); + val = readl_relaxed(wdt->base + PM_RSTC); + val &= PM_RSTC_WRCFG_CLR; + val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET; + writel_relaxed(val, wdt->base + PM_RSTC); + + /* No sleeping, possibly atomic. */ + mdelay(1); +} + +static int bcm2835_restart(struct watchdog_device *wdog, + unsigned long action, void *data) +{ + struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog); + + __bcm2835_restart(wdt); + + return 0; +} + +static const struct watchdog_ops bcm2835_wdt_ops = { .owner = THIS_MODULE, .start = bcm2835_wdt_start, .stop = bcm2835_wdt_stop, - .set_timeout = bcm2835_wdt_set_timeout, .get_timeleft = bcm2835_wdt_get_timeleft, + .restart = bcm2835_restart, }; -static struct watchdog_info bcm2835_wdt_info = { +static const struct watchdog_info bcm2835_wdt_info = { .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, .identity = "Broadcom BCM2835 Watchdog timer", @@ -103,75 +141,95 @@ static struct watchdog_device bcm2835_wdt_wdd = { .info = &bcm2835_wdt_info, .ops = &bcm2835_wdt_ops, .min_timeout = 1, - .max_timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET), + .max_hw_heartbeat_ms = WDOG_TICKS_TO_MSECS(PM_WDOG_TIME_SET), .timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET), }; +/* + * We can't really power off, but if we do the normal reset scheme, and + * indicate to bootcode.bin not to reboot, then most of the chip will be + * powered off. + */ +static void bcm2835_power_off(void) +{ + struct bcm2835_wdt *wdt = bcm2835_power_off_wdt; + u32 val; + + /* + * We set the watchdog hard reset bit here to distinguish this reset + * from the normal (full) reset. bootcode.bin will not reboot after a + * hard reset. + */ + val = readl_relaxed(wdt->base + PM_RSTS); + val |= PM_PASSWORD | PM_RSTS_RASPBERRYPI_HALT; + writel_relaxed(val, wdt->base + PM_RSTS); + + /* Continue with normal reset mechanism */ + __bcm2835_restart(wdt); +} + static int bcm2835_wdt_probe(struct platform_device *pdev) { + struct bcm2835_pm *pm = dev_get_drvdata(pdev->dev.parent); struct device *dev = &pdev->dev; - struct device_node *np = dev->of_node; struct bcm2835_wdt *wdt; int err; wdt = devm_kzalloc(dev, sizeof(struct bcm2835_wdt), GFP_KERNEL); - if (!wdt) { - dev_err(dev, "Failed to allocate memory for watchdog device"); + if (!wdt) return -ENOMEM; - } - platform_set_drvdata(pdev, wdt); spin_lock_init(&wdt->lock); - wdt->base = of_iomap(np, 0); - if (!wdt->base) { - dev_err(dev, "Failed to remap watchdog regs"); - return -ENODEV; - } + wdt->base = pm->base; watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt); watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev); watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout); - err = watchdog_register_device(&bcm2835_wdt_wdd); - if (err) { - dev_err(dev, "Failed to register watchdog device"); - iounmap(wdt->base); - return err; + bcm2835_wdt_wdd.parent = dev; + if (bcm2835_wdt_is_running(wdt)) { + /* + * The currently active timeout value (set by the + * bootloader) may be different from the module + * heartbeat parameter or the value in device + * tree. But we just need to set WDOG_HW_RUNNING, + * because then the framework will "immediately" ping + * the device, updating the timeout. + */ + set_bit(WDOG_HW_RUNNING, &bcm2835_wdt_wdd.status); } - dev_info(dev, "Broadcom BCM2835 watchdog timer"); - return 0; -} + watchdog_set_restart_priority(&bcm2835_wdt_wdd, 128); -static int bcm2835_wdt_remove(struct platform_device *pdev) -{ - struct bcm2835_wdt *wdt = platform_get_drvdata(pdev); + watchdog_stop_on_reboot(&bcm2835_wdt_wdd); + err = devm_watchdog_register_device(dev, &bcm2835_wdt_wdd); + if (err) + return err; - watchdog_unregister_device(&bcm2835_wdt_wdd); - iounmap(wdt->base); + if (of_device_is_system_power_controller(pdev->dev.parent->of_node)) { + if (!pm_power_off) { + pm_power_off = bcm2835_power_off; + bcm2835_power_off_wdt = wdt; + } else { + dev_info(dev, "Poweroff handler already present!\n"); + } + } + dev_info(dev, "Broadcom BCM2835 watchdog timer"); return 0; } -static void bcm2835_wdt_shutdown(struct platform_device *pdev) +static void bcm2835_wdt_remove(struct platform_device *pdev) { - bcm2835_wdt_stop(&bcm2835_wdt_wdd); + if (pm_power_off == bcm2835_power_off) + pm_power_off = NULL; } -static const struct of_device_id bcm2835_wdt_of_match[] = { - { .compatible = "brcm,bcm2835-pm-wdt", }, - {}, -}; -MODULE_DEVICE_TABLE(of, bcm2835_wdt_of_match); - static struct platform_driver bcm2835_wdt_driver = { .probe = bcm2835_wdt_probe, .remove = bcm2835_wdt_remove, - .shutdown = bcm2835_wdt_shutdown, .driver = { .name = "bcm2835-wdt", - .owner = THIS_MODULE, - .of_match_table = bcm2835_wdt_of_match, }, }; module_platform_driver(bcm2835_wdt_driver); @@ -183,7 +241,7 @@ module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); +MODULE_ALIAS("platform:bcm2835-wdt"); MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>"); MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer"); MODULE_LICENSE("GPL"); -MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |