diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/watchdog/sprd_wdt.c | 381 |
1 files changed, 381 insertions, 0 deletions
diff --git a/drivers/watchdog/sprd_wdt.c b/drivers/watchdog/sprd_wdt.c new file mode 100644 index 000000000..4e689b6ff --- /dev/null +++ b/drivers/watchdog/sprd_wdt.c @@ -0,0 +1,381 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Spreadtrum watchdog driver + * Copyright (C) 2017 Spreadtrum - http://www.spreadtrum.com + */ + +#include <linux/bitops.h> +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/platform_device.h> +#include <linux/watchdog.h> + +#define SPRD_WDT_LOAD_LOW 0x0 +#define SPRD_WDT_LOAD_HIGH 0x4 +#define SPRD_WDT_CTRL 0x8 +#define SPRD_WDT_INT_CLR 0xc +#define SPRD_WDT_INT_RAW 0x10 +#define SPRD_WDT_INT_MSK 0x14 +#define SPRD_WDT_CNT_LOW 0x18 +#define SPRD_WDT_CNT_HIGH 0x1c +#define SPRD_WDT_LOCK 0x20 +#define SPRD_WDT_IRQ_LOAD_LOW 0x2c +#define SPRD_WDT_IRQ_LOAD_HIGH 0x30 + +/* WDT_CTRL */ +#define SPRD_WDT_INT_EN_BIT BIT(0) +#define SPRD_WDT_CNT_EN_BIT BIT(1) +#define SPRD_WDT_NEW_VER_EN BIT(2) +#define SPRD_WDT_RST_EN_BIT BIT(3) + +/* WDT_INT_CLR */ +#define SPRD_WDT_INT_CLEAR_BIT BIT(0) +#define SPRD_WDT_RST_CLEAR_BIT BIT(3) + +/* WDT_INT_RAW */ +#define SPRD_WDT_INT_RAW_BIT BIT(0) +#define SPRD_WDT_RST_RAW_BIT BIT(3) +#define SPRD_WDT_LD_BUSY_BIT BIT(4) + +/* 1s equal to 32768 counter steps */ +#define SPRD_WDT_CNT_STEP 32768 + +#define SPRD_WDT_UNLOCK_KEY 0xe551 +#define SPRD_WDT_MIN_TIMEOUT 3 +#define SPRD_WDT_MAX_TIMEOUT 60 + +#define SPRD_WDT_CNT_HIGH_SHIFT 16 +#define SPRD_WDT_LOW_VALUE_MASK GENMASK(15, 0) +#define SPRD_WDT_LOAD_TIMEOUT 11 + +struct sprd_wdt { + void __iomem *base; + struct watchdog_device wdd; + struct clk *enable; + struct clk *rtc_enable; + int irq; +}; + +static inline struct sprd_wdt *to_sprd_wdt(struct watchdog_device *wdd) +{ + return container_of(wdd, struct sprd_wdt, wdd); +} + +static inline void sprd_wdt_lock(void __iomem *addr) +{ + writel_relaxed(0x0, addr + SPRD_WDT_LOCK); +} + +static inline void sprd_wdt_unlock(void __iomem *addr) +{ + writel_relaxed(SPRD_WDT_UNLOCK_KEY, addr + SPRD_WDT_LOCK); +} + +static irqreturn_t sprd_wdt_isr(int irq, void *dev_id) +{ + struct sprd_wdt *wdt = (struct sprd_wdt *)dev_id; + + sprd_wdt_unlock(wdt->base); + writel_relaxed(SPRD_WDT_INT_CLEAR_BIT, wdt->base + SPRD_WDT_INT_CLR); + sprd_wdt_lock(wdt->base); + watchdog_notify_pretimeout(&wdt->wdd); + return IRQ_HANDLED; +} + +static u32 sprd_wdt_get_cnt_value(struct sprd_wdt *wdt) +{ + u32 val; + + val = readl_relaxed(wdt->base + SPRD_WDT_CNT_HIGH) << + SPRD_WDT_CNT_HIGH_SHIFT; + val |= readl_relaxed(wdt->base + SPRD_WDT_CNT_LOW) & + SPRD_WDT_LOW_VALUE_MASK; + + return val; +} + +static int sprd_wdt_load_value(struct sprd_wdt *wdt, u32 timeout, + u32 pretimeout) +{ + u32 val, delay_cnt = 0; + u32 tmr_step = timeout * SPRD_WDT_CNT_STEP; + u32 prtmr_step = pretimeout * SPRD_WDT_CNT_STEP; + + /* + * Checking busy bit to make sure the previous loading operation is + * done. According to the specification, the busy bit would be set + * after a new loading operation and last 2 or 3 RTC clock + * cycles (about 60us~92us). + */ + do { + val = readl_relaxed(wdt->base + SPRD_WDT_INT_RAW); + if (!(val & SPRD_WDT_LD_BUSY_BIT)) + break; + + usleep_range(10, 100); + } while (delay_cnt++ < SPRD_WDT_LOAD_TIMEOUT); + + if (delay_cnt >= SPRD_WDT_LOAD_TIMEOUT) + return -EBUSY; + + sprd_wdt_unlock(wdt->base); + writel_relaxed((tmr_step >> SPRD_WDT_CNT_HIGH_SHIFT) & + SPRD_WDT_LOW_VALUE_MASK, wdt->base + SPRD_WDT_LOAD_HIGH); + writel_relaxed((tmr_step & SPRD_WDT_LOW_VALUE_MASK), + wdt->base + SPRD_WDT_LOAD_LOW); + writel_relaxed((prtmr_step >> SPRD_WDT_CNT_HIGH_SHIFT) & + SPRD_WDT_LOW_VALUE_MASK, + wdt->base + SPRD_WDT_IRQ_LOAD_HIGH); + writel_relaxed(prtmr_step & SPRD_WDT_LOW_VALUE_MASK, + wdt->base + SPRD_WDT_IRQ_LOAD_LOW); + sprd_wdt_lock(wdt->base); + + return 0; +} + +static int sprd_wdt_enable(struct sprd_wdt *wdt) +{ + u32 val; + int ret; + + ret = clk_prepare_enable(wdt->enable); + if (ret) + return ret; + ret = clk_prepare_enable(wdt->rtc_enable); + if (ret) { + clk_disable_unprepare(wdt->enable); + return ret; + } + + sprd_wdt_unlock(wdt->base); + val = readl_relaxed(wdt->base + SPRD_WDT_CTRL); + val |= SPRD_WDT_NEW_VER_EN; + writel_relaxed(val, wdt->base + SPRD_WDT_CTRL); + sprd_wdt_lock(wdt->base); + return 0; +} + +static void sprd_wdt_disable(void *_data) +{ + struct sprd_wdt *wdt = _data; + + sprd_wdt_unlock(wdt->base); + writel_relaxed(0x0, wdt->base + SPRD_WDT_CTRL); + sprd_wdt_lock(wdt->base); + + clk_disable_unprepare(wdt->rtc_enable); + clk_disable_unprepare(wdt->enable); +} + +static int sprd_wdt_start(struct watchdog_device *wdd) +{ + struct sprd_wdt *wdt = to_sprd_wdt(wdd); + u32 val; + int ret; + + ret = sprd_wdt_load_value(wdt, wdd->timeout, wdd->pretimeout); + if (ret) + return ret; + + sprd_wdt_unlock(wdt->base); + val = readl_relaxed(wdt->base + SPRD_WDT_CTRL); + val |= SPRD_WDT_CNT_EN_BIT | SPRD_WDT_INT_EN_BIT | SPRD_WDT_RST_EN_BIT; + writel_relaxed(val, wdt->base + SPRD_WDT_CTRL); + sprd_wdt_lock(wdt->base); + set_bit(WDOG_HW_RUNNING, &wdd->status); + + return 0; +} + +static int sprd_wdt_stop(struct watchdog_device *wdd) +{ + struct sprd_wdt *wdt = to_sprd_wdt(wdd); + u32 val; + + sprd_wdt_unlock(wdt->base); + val = readl_relaxed(wdt->base + SPRD_WDT_CTRL); + val &= ~(SPRD_WDT_CNT_EN_BIT | SPRD_WDT_RST_EN_BIT | + SPRD_WDT_INT_EN_BIT); + writel_relaxed(val, wdt->base + SPRD_WDT_CTRL); + sprd_wdt_lock(wdt->base); + return 0; +} + +static int sprd_wdt_set_timeout(struct watchdog_device *wdd, + u32 timeout) +{ + struct sprd_wdt *wdt = to_sprd_wdt(wdd); + + if (timeout == wdd->timeout) + return 0; + + wdd->timeout = timeout; + + return sprd_wdt_load_value(wdt, timeout, wdd->pretimeout); +} + +static int sprd_wdt_set_pretimeout(struct watchdog_device *wdd, + u32 new_pretimeout) +{ + struct sprd_wdt *wdt = to_sprd_wdt(wdd); + + if (new_pretimeout < wdd->min_timeout) + return -EINVAL; + + wdd->pretimeout = new_pretimeout; + + return sprd_wdt_load_value(wdt, wdd->timeout, new_pretimeout); +} + +static u32 sprd_wdt_get_timeleft(struct watchdog_device *wdd) +{ + struct sprd_wdt *wdt = to_sprd_wdt(wdd); + u32 val; + + val = sprd_wdt_get_cnt_value(wdt); + return val / SPRD_WDT_CNT_STEP; +} + +static const struct watchdog_ops sprd_wdt_ops = { + .owner = THIS_MODULE, + .start = sprd_wdt_start, + .stop = sprd_wdt_stop, + .set_timeout = sprd_wdt_set_timeout, + .set_pretimeout = sprd_wdt_set_pretimeout, + .get_timeleft = sprd_wdt_get_timeleft, +}; + +static const struct watchdog_info sprd_wdt_info = { + .options = WDIOF_SETTIMEOUT | + WDIOF_PRETIMEOUT | + WDIOF_MAGICCLOSE | + WDIOF_KEEPALIVEPING, + .identity = "Spreadtrum Watchdog Timer", +}; + +static int sprd_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct sprd_wdt *wdt; + int ret; + + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); + if (!wdt) + return -ENOMEM; + + wdt->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(wdt->base)) + return PTR_ERR(wdt->base); + + wdt->enable = devm_clk_get(dev, "enable"); + if (IS_ERR(wdt->enable)) { + dev_err(dev, "can't get the enable clock\n"); + return PTR_ERR(wdt->enable); + } + + wdt->rtc_enable = devm_clk_get(dev, "rtc_enable"); + if (IS_ERR(wdt->rtc_enable)) { + dev_err(dev, "can't get the rtc enable clock\n"); + return PTR_ERR(wdt->rtc_enable); + } + + wdt->irq = platform_get_irq(pdev, 0); + if (wdt->irq < 0) + return wdt->irq; + + ret = devm_request_irq(dev, wdt->irq, sprd_wdt_isr, IRQF_NO_SUSPEND, + "sprd-wdt", (void *)wdt); + if (ret) { + dev_err(dev, "failed to register irq\n"); + return ret; + } + + wdt->wdd.info = &sprd_wdt_info; + wdt->wdd.ops = &sprd_wdt_ops; + wdt->wdd.parent = dev; + wdt->wdd.min_timeout = SPRD_WDT_MIN_TIMEOUT; + wdt->wdd.max_timeout = SPRD_WDT_MAX_TIMEOUT; + wdt->wdd.timeout = SPRD_WDT_MAX_TIMEOUT; + + ret = sprd_wdt_enable(wdt); + if (ret) { + dev_err(dev, "failed to enable wdt\n"); + return ret; + } + ret = devm_add_action_or_reset(dev, sprd_wdt_disable, wdt); + if (ret) { + dev_err(dev, "Failed to add wdt disable action\n"); + return ret; + } + + watchdog_set_nowayout(&wdt->wdd, WATCHDOG_NOWAYOUT); + watchdog_init_timeout(&wdt->wdd, 0, dev); + + ret = devm_watchdog_register_device(dev, &wdt->wdd); + if (ret) { + sprd_wdt_disable(wdt); + return ret; + } + platform_set_drvdata(pdev, wdt); + + return 0; +} + +static int __maybe_unused sprd_wdt_pm_suspend(struct device *dev) +{ + struct sprd_wdt *wdt = dev_get_drvdata(dev); + + if (watchdog_active(&wdt->wdd)) + sprd_wdt_stop(&wdt->wdd); + sprd_wdt_disable(wdt); + + return 0; +} + +static int __maybe_unused sprd_wdt_pm_resume(struct device *dev) +{ + struct sprd_wdt *wdt = dev_get_drvdata(dev); + int ret; + + ret = sprd_wdt_enable(wdt); + if (ret) + return ret; + + if (watchdog_active(&wdt->wdd)) + ret = sprd_wdt_start(&wdt->wdd); + + return ret; +} + +static const struct dev_pm_ops sprd_wdt_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(sprd_wdt_pm_suspend, + sprd_wdt_pm_resume) +}; + +static const struct of_device_id sprd_wdt_match_table[] = { + { .compatible = "sprd,sp9860-wdt", }, + {}, +}; +MODULE_DEVICE_TABLE(of, sprd_wdt_match_table); + +static struct platform_driver sprd_watchdog_driver = { + .probe = sprd_wdt_probe, + .driver = { + .name = "sprd-wdt", + .of_match_table = sprd_wdt_match_table, + .pm = &sprd_wdt_pm_ops, + }, +}; +module_platform_driver(sprd_watchdog_driver); + +MODULE_AUTHOR("Eric Long <eric.long@spreadtrum.com>"); +MODULE_DESCRIPTION("Spreadtrum Watchdog Timer Controller Driver"); +MODULE_LICENSE("GPL v2"); |