diff options
Diffstat (limited to 'drivers/watchdog/zx2967_wdt.c')
| -rw-r--r-- | drivers/watchdog/zx2967_wdt.c | 289 |
1 files changed, 289 insertions, 0 deletions
diff --git a/drivers/watchdog/zx2967_wdt.c b/drivers/watchdog/zx2967_wdt.c new file mode 100644 index 000000000..9261f7c77 --- /dev/null +++ b/drivers/watchdog/zx2967_wdt.c @@ -0,0 +1,289 @@ +/* + * watchdog driver for ZTE's zx2967 family + * + * Copyright (C) 2017 ZTE Ltd. + * + * Author: Baoyou Xie <baoyou.xie@linaro.org> + * + * License terms: GNU General Public License (GPL) version 2 + */ + +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/mfd/syscon.h> +#include <linux/module.h> +#include <linux/of_address.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> +#include <linux/reset.h> +#include <linux/watchdog.h> + +#define ZX2967_WDT_CFG_REG 0x4 +#define ZX2967_WDT_LOAD_REG 0x8 +#define ZX2967_WDT_REFRESH_REG 0x18 +#define ZX2967_WDT_START_REG 0x1c + +#define ZX2967_WDT_REFRESH_MASK GENMASK(5, 0) + +#define ZX2967_WDT_CFG_DIV(n) ((((n) & 0xff) - 1) << 8) +#define ZX2967_WDT_START_EN 0x1 + +/* + * Hardware magic number. + * When watchdog reg is written, the lowest 16 bits are valid, but + * the highest 16 bits should be always this number. + */ +#define ZX2967_WDT_WRITEKEY (0x1234 << 16) +#define ZX2967_WDT_VAL_MASK GENMASK(15, 0) + +#define ZX2967_WDT_DIV_DEFAULT 16 +#define ZX2967_WDT_DEFAULT_TIMEOUT 32 +#define ZX2967_WDT_MIN_TIMEOUT 1 +#define ZX2967_WDT_MAX_TIMEOUT 524 +#define ZX2967_WDT_MAX_COUNT 0xffff + +#define ZX2967_WDT_CLK_FREQ 0x8000 + +#define ZX2967_WDT_FLAG_REBOOT_MON BIT(0) + +struct zx2967_wdt { + struct watchdog_device wdt_device; + void __iomem *reg_base; + struct clk *clock; +}; + +static inline u32 zx2967_wdt_readl(struct zx2967_wdt *wdt, u16 reg) +{ + return readl_relaxed(wdt->reg_base + reg); +} + +static inline void zx2967_wdt_writel(struct zx2967_wdt *wdt, u16 reg, u32 val) +{ + writel_relaxed(val | ZX2967_WDT_WRITEKEY, wdt->reg_base + reg); +} + +static void zx2967_wdt_refresh(struct zx2967_wdt *wdt) +{ + u32 val; + + val = zx2967_wdt_readl(wdt, ZX2967_WDT_REFRESH_REG); + /* + * Bit 4-5, 1 and 2: refresh config info + * Bit 2-3, 1 and 2: refresh counter + * Bit 0-1, 1 and 2: refresh int-value + * we shift each group value between 1 and 2 to refresh all data. + */ + val ^= ZX2967_WDT_REFRESH_MASK; + zx2967_wdt_writel(wdt, ZX2967_WDT_REFRESH_REG, + val & ZX2967_WDT_VAL_MASK); +} + +static int +zx2967_wdt_set_timeout(struct watchdog_device *wdd, unsigned int timeout) +{ + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd); + unsigned int divisor = ZX2967_WDT_DIV_DEFAULT; + u32 count; + + count = timeout * ZX2967_WDT_CLK_FREQ; + if (count > divisor * ZX2967_WDT_MAX_COUNT) + divisor = DIV_ROUND_UP(count, ZX2967_WDT_MAX_COUNT); + count = DIV_ROUND_UP(count, divisor); + zx2967_wdt_writel(wdt, ZX2967_WDT_CFG_REG, + ZX2967_WDT_CFG_DIV(divisor) & ZX2967_WDT_VAL_MASK); + zx2967_wdt_writel(wdt, ZX2967_WDT_LOAD_REG, + count & ZX2967_WDT_VAL_MASK); + zx2967_wdt_refresh(wdt); + wdd->timeout = (count * divisor) / ZX2967_WDT_CLK_FREQ; + + return 0; +} + +static void __zx2967_wdt_start(struct zx2967_wdt *wdt) +{ + u32 val; + + val = zx2967_wdt_readl(wdt, ZX2967_WDT_START_REG); + val |= ZX2967_WDT_START_EN; + zx2967_wdt_writel(wdt, ZX2967_WDT_START_REG, + val & ZX2967_WDT_VAL_MASK); +} + +static void __zx2967_wdt_stop(struct zx2967_wdt *wdt) +{ + u32 val; + + val = zx2967_wdt_readl(wdt, ZX2967_WDT_START_REG); + val &= ~ZX2967_WDT_START_EN; + zx2967_wdt_writel(wdt, ZX2967_WDT_START_REG, + val & ZX2967_WDT_VAL_MASK); +} + +static int zx2967_wdt_start(struct watchdog_device *wdd) +{ + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd); + + zx2967_wdt_set_timeout(wdd, wdd->timeout); + __zx2967_wdt_start(wdt); + + return 0; +} + +static int zx2967_wdt_stop(struct watchdog_device *wdd) +{ + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd); + + __zx2967_wdt_stop(wdt); + + return 0; +} + +static int zx2967_wdt_keepalive(struct watchdog_device *wdd) +{ + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd); + + zx2967_wdt_refresh(wdt); + + return 0; +} + +#define ZX2967_WDT_OPTIONS \ + (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE) +static const struct watchdog_info zx2967_wdt_ident = { + .options = ZX2967_WDT_OPTIONS, + .identity = "zx2967 watchdog", +}; + +static const struct watchdog_ops zx2967_wdt_ops = { + .owner = THIS_MODULE, + .start = zx2967_wdt_start, + .stop = zx2967_wdt_stop, + .ping = zx2967_wdt_keepalive, + .set_timeout = zx2967_wdt_set_timeout, +}; + +static void zx2967_wdt_reset_sysctrl(struct device *dev) +{ + int ret; + void __iomem *regmap; + unsigned int offset, mask, config; + struct of_phandle_args out_args; + + ret = of_parse_phandle_with_fixed_args(dev->of_node, + "zte,wdt-reset-sysctrl", 3, 0, &out_args); + if (ret) + return; + + offset = out_args.args[0]; + config = out_args.args[1]; + mask = out_args.args[2]; + + regmap = syscon_node_to_regmap(out_args.np); + if (IS_ERR(regmap)) { + of_node_put(out_args.np); + return; + } + + regmap_update_bits(regmap, offset, mask, config); + of_node_put(out_args.np); +} + +static int zx2967_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct zx2967_wdt *wdt; + struct resource *base; + int ret; + struct reset_control *rstc; + + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); + if (!wdt) + return -ENOMEM; + + platform_set_drvdata(pdev, wdt); + + wdt->wdt_device.info = &zx2967_wdt_ident; + wdt->wdt_device.ops = &zx2967_wdt_ops; + wdt->wdt_device.timeout = ZX2967_WDT_DEFAULT_TIMEOUT; + wdt->wdt_device.max_timeout = ZX2967_WDT_MAX_TIMEOUT; + wdt->wdt_device.min_timeout = ZX2967_WDT_MIN_TIMEOUT; + wdt->wdt_device.parent = &pdev->dev; + + base = platform_get_resource(pdev, IORESOURCE_MEM, 0); + wdt->reg_base = devm_ioremap_resource(dev, base); + if (IS_ERR(wdt->reg_base)) + return PTR_ERR(wdt->reg_base); + + zx2967_wdt_reset_sysctrl(dev); + + wdt->clock = devm_clk_get(dev, NULL); + if (IS_ERR(wdt->clock)) { + dev_err(dev, "failed to find watchdog clock source\n"); + return PTR_ERR(wdt->clock); + } + + ret = clk_prepare_enable(wdt->clock); + if (ret < 0) { + dev_err(dev, "failed to enable clock\n"); + return ret; + } + clk_set_rate(wdt->clock, ZX2967_WDT_CLK_FREQ); + + rstc = devm_reset_control_get_exclusive(dev, NULL); + if (IS_ERR(rstc)) { + dev_err(dev, "failed to get rstc"); + ret = PTR_ERR(rstc); + goto err; + } + + reset_control_assert(rstc); + reset_control_deassert(rstc); + + watchdog_set_drvdata(&wdt->wdt_device, wdt); + watchdog_init_timeout(&wdt->wdt_device, + ZX2967_WDT_DEFAULT_TIMEOUT, dev); + watchdog_set_nowayout(&wdt->wdt_device, WATCHDOG_NOWAYOUT); + + ret = watchdog_register_device(&wdt->wdt_device); + if (ret) + goto err; + + dev_info(dev, "watchdog enabled (timeout=%d sec, nowayout=%d)", + wdt->wdt_device.timeout, WATCHDOG_NOWAYOUT); + + return 0; + +err: + clk_disable_unprepare(wdt->clock); + return ret; +} + +static int zx2967_wdt_remove(struct platform_device *pdev) +{ + struct zx2967_wdt *wdt = platform_get_drvdata(pdev); + + watchdog_unregister_device(&wdt->wdt_device); + clk_disable_unprepare(wdt->clock); + + return 0; +} + +static const struct of_device_id zx2967_wdt_match[] = { + { .compatible = "zte,zx296718-wdt", }, + {} +}; +MODULE_DEVICE_TABLE(of, zx2967_wdt_match); + +static struct platform_driver zx2967_wdt_driver = { + .probe = zx2967_wdt_probe, + .remove = zx2967_wdt_remove, + .driver = { + .name = "zx2967-wdt", + .of_match_table = of_match_ptr(zx2967_wdt_match), + }, +}; +module_platform_driver(zx2967_wdt_driver); + +MODULE_AUTHOR("Baoyou Xie <baoyou.xie@linaro.org>"); +MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver"); +MODULE_LICENSE("GPL v2"); |