diff options
Diffstat (limited to 'drivers/watchdog/lantiq_wdt.c')
| -rw-r--r-- | drivers/watchdog/lantiq_wdt.c | 288 |
1 files changed, 288 insertions, 0 deletions
diff --git a/drivers/watchdog/lantiq_wdt.c b/drivers/watchdog/lantiq_wdt.c new file mode 100644 index 000000000..6fab504af --- /dev/null +++ b/drivers/watchdog/lantiq_wdt.c @@ -0,0 +1,288 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * + * Copyright (C) 2010 John Crispin <john@phrozen.org> + * Copyright (C) 2017 Hauke Mehrtens <hauke@hauke-m.de> + * Based on EP93xx wdt driver + */ + +#include <linux/module.h> +#include <linux/bitops.h> +#include <linux/watchdog.h> +#include <linux/of_platform.h> +#include <linux/uaccess.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/regmap.h> +#include <linux/mfd/syscon.h> + +#include <lantiq_soc.h> + +#define LTQ_XRX_RCU_RST_STAT 0x0014 +#define LTQ_XRX_RCU_RST_STAT_WDT BIT(31) + +/* CPU0 Reset Source Register */ +#define LTQ_FALCON_SYS1_CPU0RS 0x0060 +/* reset cause mask */ +#define LTQ_FALCON_SYS1_CPU0RS_MASK 0x0007 +#define LTQ_FALCON_SYS1_CPU0RS_WDT 0x02 + +/* + * Section 3.4 of the datasheet + * The password sequence protects the WDT control register from unintended + * write actions, which might cause malfunction of the WDT. + * + * essentially the following two magic passwords need to be written to allow + * IO access to the WDT core + */ +#define LTQ_WDT_CR_PW1 0x00BE0000 +#define LTQ_WDT_CR_PW2 0x00DC0000 + +#define LTQ_WDT_CR 0x0 /* watchdog control register */ +#define LTQ_WDT_CR_GEN BIT(31) /* enable bit */ +/* Pre-warning limit set to 1/16 of max WDT period */ +#define LTQ_WDT_CR_PWL (0x3 << 26) +/* set clock divider to 0x40000 */ +#define LTQ_WDT_CR_CLKDIV (0x3 << 24) +#define LTQ_WDT_CR_PW_MASK GENMASK(23, 16) /* Password field */ +#define LTQ_WDT_CR_MAX_TIMEOUT ((1 << 16) - 1) /* The reload field is 16 bit */ +#define LTQ_WDT_SR 0x8 /* watchdog status register */ +#define LTQ_WDT_SR_EN BIT(31) /* Enable */ +#define LTQ_WDT_SR_VALUE_MASK GENMASK(15, 0) /* Timer value */ + +#define LTQ_WDT_DIVIDER 0x40000 + +static bool nowayout = WATCHDOG_NOWAYOUT; + +struct ltq_wdt_hw { + int (*bootstatus_get)(struct device *dev); +}; + +struct ltq_wdt_priv { + struct watchdog_device wdt; + void __iomem *membase; + unsigned long clk_rate; +}; + +static u32 ltq_wdt_r32(struct ltq_wdt_priv *priv, u32 offset) +{ + return __raw_readl(priv->membase + offset); +} + +static void ltq_wdt_w32(struct ltq_wdt_priv *priv, u32 val, u32 offset) +{ + __raw_writel(val, priv->membase + offset); +} + +static void ltq_wdt_mask(struct ltq_wdt_priv *priv, u32 clear, u32 set, + u32 offset) +{ + u32 val = ltq_wdt_r32(priv, offset); + + val &= ~(clear); + val |= set; + ltq_wdt_w32(priv, val, offset); +} + +static struct ltq_wdt_priv *ltq_wdt_get_priv(struct watchdog_device *wdt) +{ + return container_of(wdt, struct ltq_wdt_priv, wdt); +} + +static struct watchdog_info ltq_wdt_info = { + .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | + WDIOF_CARDRESET, + .identity = "ltq_wdt", +}; + +static int ltq_wdt_start(struct watchdog_device *wdt) +{ + struct ltq_wdt_priv *priv = ltq_wdt_get_priv(wdt); + u32 timeout; + + timeout = wdt->timeout * priv->clk_rate; + + ltq_wdt_mask(priv, LTQ_WDT_CR_PW_MASK, LTQ_WDT_CR_PW1, LTQ_WDT_CR); + /* write the second magic plus the configuration and new timeout */ + ltq_wdt_mask(priv, LTQ_WDT_CR_PW_MASK | LTQ_WDT_CR_MAX_TIMEOUT, + LTQ_WDT_CR_GEN | LTQ_WDT_CR_PWL | LTQ_WDT_CR_CLKDIV | + LTQ_WDT_CR_PW2 | timeout, + LTQ_WDT_CR); + + return 0; +} + +static int ltq_wdt_stop(struct watchdog_device *wdt) +{ + struct ltq_wdt_priv *priv = ltq_wdt_get_priv(wdt); + + ltq_wdt_mask(priv, LTQ_WDT_CR_PW_MASK, LTQ_WDT_CR_PW1, LTQ_WDT_CR); + ltq_wdt_mask(priv, LTQ_WDT_CR_GEN | LTQ_WDT_CR_PW_MASK, + LTQ_WDT_CR_PW2, LTQ_WDT_CR); + + return 0; +} + +static int ltq_wdt_ping(struct watchdog_device *wdt) +{ + struct ltq_wdt_priv *priv = ltq_wdt_get_priv(wdt); + u32 timeout; + + timeout = wdt->timeout * priv->clk_rate; + + ltq_wdt_mask(priv, LTQ_WDT_CR_PW_MASK, LTQ_WDT_CR_PW1, LTQ_WDT_CR); + /* write the second magic plus the configuration and new timeout */ + ltq_wdt_mask(priv, LTQ_WDT_CR_PW_MASK | LTQ_WDT_CR_MAX_TIMEOUT, + LTQ_WDT_CR_PW2 | timeout, LTQ_WDT_CR); + + return 0; +} + +static unsigned int ltq_wdt_get_timeleft(struct watchdog_device *wdt) +{ + struct ltq_wdt_priv *priv = ltq_wdt_get_priv(wdt); + u64 timeout; + + timeout = ltq_wdt_r32(priv, LTQ_WDT_SR) & LTQ_WDT_SR_VALUE_MASK; + return do_div(timeout, priv->clk_rate); +} + +static const struct watchdog_ops ltq_wdt_ops = { + .owner = THIS_MODULE, + .start = ltq_wdt_start, + .stop = ltq_wdt_stop, + .ping = ltq_wdt_ping, + .get_timeleft = ltq_wdt_get_timeleft, +}; + +static int ltq_wdt_xrx_bootstatus_get(struct device *dev) +{ + struct regmap *rcu_regmap; + u32 val; + int err; + + rcu_regmap = syscon_regmap_lookup_by_phandle(dev->of_node, "regmap"); + if (IS_ERR(rcu_regmap)) + return PTR_ERR(rcu_regmap); + + err = regmap_read(rcu_regmap, LTQ_XRX_RCU_RST_STAT, &val); + if (err) + return err; + + if (val & LTQ_XRX_RCU_RST_STAT_WDT) + return WDIOF_CARDRESET; + + return 0; +} + +static int ltq_wdt_falcon_bootstatus_get(struct device *dev) +{ + struct regmap *rcu_regmap; + u32 val; + int err; + + rcu_regmap = syscon_regmap_lookup_by_phandle(dev->of_node, + "lantiq,rcu"); + if (IS_ERR(rcu_regmap)) + return PTR_ERR(rcu_regmap); + + err = regmap_read(rcu_regmap, LTQ_FALCON_SYS1_CPU0RS, &val); + if (err) + return err; + + if ((val & LTQ_FALCON_SYS1_CPU0RS_MASK) == LTQ_FALCON_SYS1_CPU0RS_WDT) + return WDIOF_CARDRESET; + + return 0; +} + +static int ltq_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct ltq_wdt_priv *priv; + struct watchdog_device *wdt; + struct clk *clk; + const struct ltq_wdt_hw *ltq_wdt_hw; + int ret; + u32 status; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->membase = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(priv->membase)) + return PTR_ERR(priv->membase); + + /* we do not need to enable the clock as it is always running */ + clk = clk_get_io(); + priv->clk_rate = clk_get_rate(clk) / LTQ_WDT_DIVIDER; + if (!priv->clk_rate) { + dev_err(dev, "clock rate less than divider %i\n", + LTQ_WDT_DIVIDER); + return -EINVAL; + } + + wdt = &priv->wdt; + wdt->info = <q_wdt_info; + wdt->ops = <q_wdt_ops; + wdt->min_timeout = 1; + wdt->max_timeout = LTQ_WDT_CR_MAX_TIMEOUT / priv->clk_rate; + wdt->timeout = wdt->max_timeout; + wdt->parent = dev; + + ltq_wdt_hw = of_device_get_match_data(dev); + if (ltq_wdt_hw && ltq_wdt_hw->bootstatus_get) { + ret = ltq_wdt_hw->bootstatus_get(dev); + if (ret >= 0) + wdt->bootstatus = ret; + } + + watchdog_set_nowayout(wdt, nowayout); + watchdog_init_timeout(wdt, 0, dev); + + status = ltq_wdt_r32(priv, LTQ_WDT_SR); + if (status & LTQ_WDT_SR_EN) { + /* + * If the watchdog is already running overwrite it with our + * new settings. Stop is not needed as the start call will + * replace all settings anyway. + */ + ltq_wdt_start(wdt); + set_bit(WDOG_HW_RUNNING, &wdt->status); + } + + return devm_watchdog_register_device(dev, wdt); +} + +static const struct ltq_wdt_hw ltq_wdt_xrx100 = { + .bootstatus_get = ltq_wdt_xrx_bootstatus_get, +}; + +static const struct ltq_wdt_hw ltq_wdt_falcon = { + .bootstatus_get = ltq_wdt_falcon_bootstatus_get, +}; + +static const struct of_device_id ltq_wdt_match[] = { + { .compatible = "lantiq,wdt", .data = NULL }, + { .compatible = "lantiq,xrx100-wdt", .data = <q_wdt_xrx100 }, + { .compatible = "lantiq,falcon-wdt", .data = <q_wdt_falcon }, + {}, +}; +MODULE_DEVICE_TABLE(of, ltq_wdt_match); + +static struct platform_driver ltq_wdt_driver = { + .probe = ltq_wdt_probe, + .driver = { + .name = "wdt", + .of_match_table = ltq_wdt_match, + }, +}; + +module_platform_driver(ltq_wdt_driver); + +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); +MODULE_AUTHOR("John Crispin <john@phrozen.org>"); +MODULE_DESCRIPTION("Lantiq SoC Watchdog"); +MODULE_LICENSE("GPL"); |