diff options
Diffstat (limited to 'drivers/watchdog/kempld_wdt.c')
| -rw-r--r-- | drivers/watchdog/kempld_wdt.c | 552 |
1 files changed, 552 insertions, 0 deletions
diff --git a/drivers/watchdog/kempld_wdt.c b/drivers/watchdog/kempld_wdt.c new file mode 100644 index 000000000..40bd518ed --- /dev/null +++ b/drivers/watchdog/kempld_wdt.c @@ -0,0 +1,552 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Kontron PLD watchdog driver + * + * Copyright (c) 2010-2013 Kontron Europe GmbH + * Author: Michael Brunner <michael.brunner@kontron.com> + * + * Note: From the PLD watchdog point of view timeout and pretimeout are + * defined differently than in the kernel. + * First the pretimeout stage runs out before the timeout stage gets + * active. + * + * Kernel/API: P-----| pretimeout + * |-----------------------T timeout + * Watchdog: |-----------------P pretimeout_stage + * |-----T timeout_stage + */ + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/uaccess.h> +#include <linux/watchdog.h> +#include <linux/platform_device.h> +#include <linux/mfd/kempld.h> + +#define KEMPLD_WDT_STAGE_TIMEOUT(x) (0x1b + (x) * 4) +#define KEMPLD_WDT_STAGE_CFG(x) (0x18 + (x)) +#define STAGE_CFG_GET_PRESCALER(x) (((x) & 0x30) >> 4) +#define STAGE_CFG_SET_PRESCALER(x) (((x) & 0x3) << 4) +#define STAGE_CFG_PRESCALER_MASK 0x30 +#define STAGE_CFG_ACTION_MASK 0x7 +#define STAGE_CFG_ASSERT (1 << 3) + +#define KEMPLD_WDT_MAX_STAGES 2 +#define KEMPLD_WDT_KICK 0x16 +#define KEMPLD_WDT_CFG 0x17 +#define KEMPLD_WDT_CFG_ENABLE 0x10 +#define KEMPLD_WDT_CFG_ENABLE_LOCK 0x8 +#define KEMPLD_WDT_CFG_GLOBAL_LOCK 0x80 + +enum { + ACTION_NONE = 0, + ACTION_RESET, + ACTION_NMI, + ACTION_SMI, + ACTION_SCI, + ACTION_DELAY, +}; + +enum { + STAGE_TIMEOUT = 0, + STAGE_PRETIMEOUT, +}; + +enum { + PRESCALER_21 = 0, + PRESCALER_17, + PRESCALER_12, +}; + +static const u32 kempld_prescaler[] = { + [PRESCALER_21] = (1 << 21) - 1, + [PRESCALER_17] = (1 << 17) - 1, + [PRESCALER_12] = (1 << 12) - 1, + 0, +}; + +struct kempld_wdt_stage { + unsigned int id; + u32 mask; +}; + +struct kempld_wdt_data { + struct kempld_device_data *pld; + struct watchdog_device wdd; + unsigned int pretimeout; + struct kempld_wdt_stage stage[KEMPLD_WDT_MAX_STAGES]; +#ifdef CONFIG_PM + u8 pm_status_store; +#endif +}; + +#define DEFAULT_TIMEOUT 30 /* seconds */ +#define DEFAULT_PRETIMEOUT 0 + +static unsigned int timeout = DEFAULT_TIMEOUT; +module_param(timeout, uint, 0); +MODULE_PARM_DESC(timeout, + "Watchdog timeout in seconds. (>=0, default=" + __MODULE_STRING(DEFAULT_TIMEOUT) ")"); + +static unsigned int pretimeout = DEFAULT_PRETIMEOUT; +module_param(pretimeout, uint, 0); +MODULE_PARM_DESC(pretimeout, + "Watchdog pretimeout in seconds. (>=0, default=" + __MODULE_STRING(DEFAULT_PRETIMEOUT) ")"); + +static bool nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, + "Watchdog cannot be stopped once started (default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +static int kempld_wdt_set_stage_action(struct kempld_wdt_data *wdt_data, + struct kempld_wdt_stage *stage, + u8 action) +{ + struct kempld_device_data *pld = wdt_data->pld; + u8 stage_cfg; + + if (!stage || !stage->mask) + return -EINVAL; + + kempld_get_mutex(pld); + stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id)); + stage_cfg &= ~STAGE_CFG_ACTION_MASK; + stage_cfg |= (action & STAGE_CFG_ACTION_MASK); + + if (action == ACTION_RESET) + stage_cfg |= STAGE_CFG_ASSERT; + else + stage_cfg &= ~STAGE_CFG_ASSERT; + + kempld_write8(pld, KEMPLD_WDT_STAGE_CFG(stage->id), stage_cfg); + kempld_release_mutex(pld); + + return 0; +} + +static int kempld_wdt_set_stage_timeout(struct kempld_wdt_data *wdt_data, + struct kempld_wdt_stage *stage, + unsigned int timeout) +{ + struct kempld_device_data *pld = wdt_data->pld; + u32 prescaler; + u64 stage_timeout64; + u32 stage_timeout; + u32 remainder; + u8 stage_cfg; + + prescaler = kempld_prescaler[PRESCALER_21]; + + if (!stage) + return -EINVAL; + + stage_timeout64 = (u64)timeout * pld->pld_clock; + remainder = do_div(stage_timeout64, prescaler); + if (remainder) + stage_timeout64++; + + if (stage_timeout64 > stage->mask) + return -EINVAL; + + stage_timeout = stage_timeout64 & stage->mask; + + kempld_get_mutex(pld); + stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id)); + stage_cfg &= ~STAGE_CFG_PRESCALER_MASK; + stage_cfg |= STAGE_CFG_SET_PRESCALER(PRESCALER_21); + kempld_write8(pld, KEMPLD_WDT_STAGE_CFG(stage->id), stage_cfg); + kempld_write32(pld, KEMPLD_WDT_STAGE_TIMEOUT(stage->id), + stage_timeout); + kempld_release_mutex(pld); + + return 0; +} + +/* + * kempld_get_mutex must be called prior to calling this function. + */ +static unsigned int kempld_wdt_get_timeout(struct kempld_wdt_data *wdt_data, + struct kempld_wdt_stage *stage) +{ + struct kempld_device_data *pld = wdt_data->pld; + unsigned int timeout; + u64 stage_timeout; + u32 prescaler; + u32 remainder; + u8 stage_cfg; + + if (!stage->mask) + return 0; + + stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id)); + stage_timeout = kempld_read32(pld, KEMPLD_WDT_STAGE_TIMEOUT(stage->id)); + prescaler = kempld_prescaler[STAGE_CFG_GET_PRESCALER(stage_cfg)]; + + stage_timeout = (stage_timeout & stage->mask) * prescaler; + remainder = do_div(stage_timeout, pld->pld_clock); + if (remainder) + stage_timeout++; + + timeout = stage_timeout; + WARN_ON_ONCE(timeout != stage_timeout); + + return timeout; +} + +static int kempld_wdt_set_timeout(struct watchdog_device *wdd, + unsigned int timeout) +{ + struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd); + struct kempld_wdt_stage *pretimeout_stage; + struct kempld_wdt_stage *timeout_stage; + int ret; + + timeout_stage = &wdt_data->stage[STAGE_TIMEOUT]; + pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT]; + + if (pretimeout_stage->mask && wdt_data->pretimeout > 0) + timeout = wdt_data->pretimeout; + + ret = kempld_wdt_set_stage_action(wdt_data, timeout_stage, + ACTION_RESET); + if (ret) + return ret; + ret = kempld_wdt_set_stage_timeout(wdt_data, timeout_stage, + timeout); + if (ret) + return ret; + + wdd->timeout = timeout; + return 0; +} + +static int kempld_wdt_set_pretimeout(struct watchdog_device *wdd, + unsigned int pretimeout) +{ + struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd); + struct kempld_wdt_stage *pretimeout_stage; + u8 action = ACTION_NONE; + int ret; + + pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT]; + + if (!pretimeout_stage->mask) + return -ENXIO; + + if (pretimeout > wdd->timeout) + return -EINVAL; + + if (pretimeout > 0) + action = ACTION_NMI; + + ret = kempld_wdt_set_stage_action(wdt_data, pretimeout_stage, + action); + if (ret) + return ret; + ret = kempld_wdt_set_stage_timeout(wdt_data, pretimeout_stage, + wdd->timeout - pretimeout); + if (ret) + return ret; + + wdt_data->pretimeout = pretimeout; + return 0; +} + +static void kempld_wdt_update_timeouts(struct kempld_wdt_data *wdt_data) +{ + struct kempld_device_data *pld = wdt_data->pld; + struct kempld_wdt_stage *pretimeout_stage; + struct kempld_wdt_stage *timeout_stage; + unsigned int pretimeout, timeout; + + pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT]; + timeout_stage = &wdt_data->stage[STAGE_TIMEOUT]; + + kempld_get_mutex(pld); + pretimeout = kempld_wdt_get_timeout(wdt_data, pretimeout_stage); + timeout = kempld_wdt_get_timeout(wdt_data, timeout_stage); + kempld_release_mutex(pld); + + if (pretimeout) + wdt_data->pretimeout = timeout; + else + wdt_data->pretimeout = 0; + + wdt_data->wdd.timeout = pretimeout + timeout; +} + +static int kempld_wdt_start(struct watchdog_device *wdd) +{ + struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd); + struct kempld_device_data *pld = wdt_data->pld; + u8 status; + int ret; + + ret = kempld_wdt_set_timeout(wdd, wdd->timeout); + if (ret) + return ret; + + kempld_get_mutex(pld); + status = kempld_read8(pld, KEMPLD_WDT_CFG); + status |= KEMPLD_WDT_CFG_ENABLE; + kempld_write8(pld, KEMPLD_WDT_CFG, status); + status = kempld_read8(pld, KEMPLD_WDT_CFG); + kempld_release_mutex(pld); + + /* Check if the watchdog was enabled */ + if (!(status & KEMPLD_WDT_CFG_ENABLE)) + return -EACCES; + + return 0; +} + +static int kempld_wdt_stop(struct watchdog_device *wdd) +{ + struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd); + struct kempld_device_data *pld = wdt_data->pld; + u8 status; + + kempld_get_mutex(pld); + status = kempld_read8(pld, KEMPLD_WDT_CFG); + status &= ~KEMPLD_WDT_CFG_ENABLE; + kempld_write8(pld, KEMPLD_WDT_CFG, status); + status = kempld_read8(pld, KEMPLD_WDT_CFG); + kempld_release_mutex(pld); + + /* Check if the watchdog was disabled */ + if (status & KEMPLD_WDT_CFG_ENABLE) + return -EACCES; + + return 0; +} + +static int kempld_wdt_keepalive(struct watchdog_device *wdd) +{ + struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd); + struct kempld_device_data *pld = wdt_data->pld; + + kempld_get_mutex(pld); + kempld_write8(pld, KEMPLD_WDT_KICK, 'K'); + kempld_release_mutex(pld); + + return 0; +} + +static long kempld_wdt_ioctl(struct watchdog_device *wdd, unsigned int cmd, + unsigned long arg) +{ + struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd); + void __user *argp = (void __user *)arg; + int ret = -ENOIOCTLCMD; + int __user *p = argp; + int new_value; + + switch (cmd) { + case WDIOC_SETPRETIMEOUT: + if (get_user(new_value, p)) + return -EFAULT; + ret = kempld_wdt_set_pretimeout(wdd, new_value); + if (ret) + return ret; + ret = kempld_wdt_keepalive(wdd); + break; + case WDIOC_GETPRETIMEOUT: + ret = put_user(wdt_data->pretimeout, (int __user *)arg); + break; + } + + return ret; +} + +static int kempld_wdt_probe_stages(struct watchdog_device *wdd) +{ + struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd); + struct kempld_device_data *pld = wdt_data->pld; + struct kempld_wdt_stage *pretimeout_stage; + struct kempld_wdt_stage *timeout_stage; + u8 index, data, data_orig; + u32 mask; + int i, j; + + pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT]; + timeout_stage = &wdt_data->stage[STAGE_TIMEOUT]; + + pretimeout_stage->mask = 0; + timeout_stage->mask = 0; + + for (i = 0; i < 3; i++) { + index = KEMPLD_WDT_STAGE_TIMEOUT(i); + mask = 0; + + kempld_get_mutex(pld); + /* Probe each byte individually. */ + for (j = 0; j < 4; j++) { + data_orig = kempld_read8(pld, index + j); + kempld_write8(pld, index + j, 0x00); + data = kempld_read8(pld, index + j); + /* A failed write means this byte is reserved */ + if (data != 0x00) + break; + kempld_write8(pld, index + j, data_orig); + mask |= 0xff << (j * 8); + } + kempld_release_mutex(pld); + + /* Assign available stages to timeout and pretimeout */ + if (!timeout_stage->mask) { + timeout_stage->mask = mask; + timeout_stage->id = i; + } else { + if (pld->feature_mask & KEMPLD_FEATURE_BIT_NMI) { + pretimeout_stage->mask = timeout_stage->mask; + timeout_stage->mask = mask; + pretimeout_stage->id = timeout_stage->id; + timeout_stage->id = i; + } + break; + } + } + + if (!timeout_stage->mask) + return -ENODEV; + + return 0; +} + +static const struct watchdog_info kempld_wdt_info = { + .identity = "KEMPLD Watchdog", + .options = WDIOF_SETTIMEOUT | + WDIOF_KEEPALIVEPING | + WDIOF_MAGICCLOSE | + WDIOF_PRETIMEOUT +}; + +static const struct watchdog_ops kempld_wdt_ops = { + .owner = THIS_MODULE, + .start = kempld_wdt_start, + .stop = kempld_wdt_stop, + .ping = kempld_wdt_keepalive, + .set_timeout = kempld_wdt_set_timeout, + .ioctl = kempld_wdt_ioctl, +}; + +static int kempld_wdt_probe(struct platform_device *pdev) +{ + struct kempld_device_data *pld = dev_get_drvdata(pdev->dev.parent); + struct kempld_wdt_data *wdt_data; + struct device *dev = &pdev->dev; + struct watchdog_device *wdd; + u8 status; + int ret = 0; + + wdt_data = devm_kzalloc(dev, sizeof(*wdt_data), GFP_KERNEL); + if (!wdt_data) + return -ENOMEM; + + wdt_data->pld = pld; + wdd = &wdt_data->wdd; + wdd->parent = dev; + + kempld_get_mutex(pld); + status = kempld_read8(pld, KEMPLD_WDT_CFG); + kempld_release_mutex(pld); + + /* Enable nowayout if watchdog is already locked */ + if (status & (KEMPLD_WDT_CFG_ENABLE_LOCK | + KEMPLD_WDT_CFG_GLOBAL_LOCK)) { + if (!nowayout) + dev_warn(dev, + "Forcing nowayout - watchdog lock enabled!\n"); + nowayout = true; + } + + wdd->info = &kempld_wdt_info; + wdd->ops = &kempld_wdt_ops; + + watchdog_set_drvdata(wdd, wdt_data); + watchdog_set_nowayout(wdd, nowayout); + + ret = kempld_wdt_probe_stages(wdd); + if (ret) + return ret; + + kempld_wdt_set_timeout(wdd, timeout); + kempld_wdt_set_pretimeout(wdd, pretimeout); + + /* Check if watchdog is already enabled */ + if (status & KEMPLD_WDT_CFG_ENABLE) { + /* Get current watchdog settings */ + kempld_wdt_update_timeouts(wdt_data); + dev_info(dev, "Watchdog was already enabled\n"); + } + + platform_set_drvdata(pdev, wdt_data); + watchdog_stop_on_reboot(wdd); + watchdog_stop_on_unregister(wdd); + ret = devm_watchdog_register_device(dev, wdd); + if (ret) + return ret; + + dev_info(dev, "Watchdog registered with %ds timeout\n", wdd->timeout); + + return 0; +} + +#ifdef CONFIG_PM +/* Disable watchdog if it is active during suspend */ +static int kempld_wdt_suspend(struct platform_device *pdev, + pm_message_t message) +{ + struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev); + struct kempld_device_data *pld = wdt_data->pld; + struct watchdog_device *wdd = &wdt_data->wdd; + + kempld_get_mutex(pld); + wdt_data->pm_status_store = kempld_read8(pld, KEMPLD_WDT_CFG); + kempld_release_mutex(pld); + + kempld_wdt_update_timeouts(wdt_data); + + if (wdt_data->pm_status_store & KEMPLD_WDT_CFG_ENABLE) + return kempld_wdt_stop(wdd); + + return 0; +} + +/* Enable watchdog and configure it if necessary */ +static int kempld_wdt_resume(struct platform_device *pdev) +{ + struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev); + struct watchdog_device *wdd = &wdt_data->wdd; + + /* + * If watchdog was stopped before suspend be sure it gets disabled + * again, for the case BIOS has enabled it during resume + */ + if (wdt_data->pm_status_store & KEMPLD_WDT_CFG_ENABLE) + return kempld_wdt_start(wdd); + else + return kempld_wdt_stop(wdd); +} +#else +#define kempld_wdt_suspend NULL +#define kempld_wdt_resume NULL +#endif + +static struct platform_driver kempld_wdt_driver = { + .driver = { + .name = "kempld-wdt", + }, + .probe = kempld_wdt_probe, + .suspend = kempld_wdt_suspend, + .resume = kempld_wdt_resume, +}; + +module_platform_driver(kempld_wdt_driver); + +MODULE_DESCRIPTION("KEM PLD Watchdog Driver"); +MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>"); +MODULE_LICENSE("GPL"); |