From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- drivers/watchdog/rzn1_wdt.c | 187 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 187 insertions(+) create mode 100644 drivers/watchdog/rzn1_wdt.c (limited to 'drivers/watchdog/rzn1_wdt.c') diff --git a/drivers/watchdog/rzn1_wdt.c b/drivers/watchdog/rzn1_wdt.c new file mode 100644 index 0000000000..980c1717ad --- /dev/null +++ b/drivers/watchdog/rzn1_wdt.c @@ -0,0 +1,187 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Renesas RZ/N1 Watchdog timer. + * This is a 12-bit timer driver from a (62.5/16384) MHz clock. It can't even + * cope with 2 seconds. + * + * Copyright 2018 Renesas Electronics Europe Ltd. + * + * Derived from Ralink RT288x watchdog timer. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define DEFAULT_TIMEOUT 60 + +#define RZN1_WDT_RETRIGGER 0x0 +#define RZN1_WDT_RETRIGGER_RELOAD_VAL 0 +#define RZN1_WDT_RETRIGGER_RELOAD_VAL_MASK 0xfff +#define RZN1_WDT_RETRIGGER_PRESCALE BIT(12) +#define RZN1_WDT_RETRIGGER_ENABLE BIT(13) +#define RZN1_WDT_RETRIGGER_WDSI (0x2 << 14) + +#define RZN1_WDT_PRESCALER 16384 +#define RZN1_WDT_MAX 4095 + +struct rzn1_watchdog { + struct watchdog_device wdtdev; + void __iomem *base; + unsigned long clk_rate_khz; +}; + +static inline uint32_t max_heart_beat_ms(unsigned long clk_rate_khz) +{ + return (RZN1_WDT_MAX * RZN1_WDT_PRESCALER) / clk_rate_khz; +} + +static inline uint32_t compute_reload_value(uint32_t tick_ms, + unsigned long clk_rate_khz) +{ + return (tick_ms * clk_rate_khz) / RZN1_WDT_PRESCALER; +} + +static int rzn1_wdt_ping(struct watchdog_device *w) +{ + struct rzn1_watchdog *wdt = watchdog_get_drvdata(w); + + /* Any value retrigggers the watchdog */ + writel(0, wdt->base + RZN1_WDT_RETRIGGER); + + return 0; +} + +static int rzn1_wdt_start(struct watchdog_device *w) +{ + struct rzn1_watchdog *wdt = watchdog_get_drvdata(w); + u32 val; + + /* + * The hardware allows you to write to this reg only once. + * Since this includes the reload value, there is no way to change the + * timeout once started. Also note that the WDT clock is half the bus + * fabric clock rate, so if the bus fabric clock rate is changed after + * the WDT is started, the WDT interval will be wrong. + */ + val = RZN1_WDT_RETRIGGER_WDSI; + val |= RZN1_WDT_RETRIGGER_ENABLE; + val |= RZN1_WDT_RETRIGGER_PRESCALE; + val |= compute_reload_value(w->max_hw_heartbeat_ms, wdt->clk_rate_khz); + writel(val, wdt->base + RZN1_WDT_RETRIGGER); + + return 0; +} + +static irqreturn_t rzn1_wdt_irq(int irq, void *_wdt) +{ + pr_crit("RZN1 Watchdog. Initiating system reboot\n"); + emergency_restart(); + + return IRQ_HANDLED; +} + +static struct watchdog_info rzn1_wdt_info = { + .identity = "RZ/N1 Watchdog", + .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, +}; + +static const struct watchdog_ops rzn1_wdt_ops = { + .owner = THIS_MODULE, + .start = rzn1_wdt_start, + .ping = rzn1_wdt_ping, +}; + +static int rzn1_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct rzn1_watchdog *wdt; + struct device_node *np = dev->of_node; + struct clk *clk; + unsigned long clk_rate; + int ret; + int irq; + + 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); + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return irq; + + ret = devm_request_irq(dev, irq, rzn1_wdt_irq, 0, + np->name, wdt); + if (ret) { + dev_err(dev, "failed to request irq %d\n", irq); + return ret; + } + + clk = devm_clk_get_enabled(dev, NULL); + if (IS_ERR(clk)) { + dev_err(dev, "failed to get the clock\n"); + return PTR_ERR(clk); + } + + clk_rate = clk_get_rate(clk); + if (!clk_rate) { + dev_err(dev, "failed to get the clock rate\n"); + return -EINVAL; + } + + wdt->clk_rate_khz = clk_rate / 1000; + wdt->wdtdev.info = &rzn1_wdt_info, + wdt->wdtdev.ops = &rzn1_wdt_ops, + wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS, + wdt->wdtdev.parent = dev; + /* + * The period of the watchdog cannot be changed once set + * and is limited to a very short period. + * Configure it for a 1s period once and for all, and + * rely on the heart-beat provided by the watchdog core + * to make this usable by the user-space. + */ + wdt->wdtdev.max_hw_heartbeat_ms = max_heart_beat_ms(wdt->clk_rate_khz); + if (wdt->wdtdev.max_hw_heartbeat_ms > 1000) + wdt->wdtdev.max_hw_heartbeat_ms = 1000; + + wdt->wdtdev.timeout = DEFAULT_TIMEOUT; + ret = watchdog_init_timeout(&wdt->wdtdev, 0, dev); + if (ret) + return ret; + + watchdog_set_drvdata(&wdt->wdtdev, wdt); + + return devm_watchdog_register_device(dev, &wdt->wdtdev); +} + + +static const struct of_device_id rzn1_wdt_match[] = { + { .compatible = "renesas,rzn1-wdt" }, + {}, +}; +MODULE_DEVICE_TABLE(of, rzn1_wdt_match); + +static struct platform_driver rzn1_wdt_driver = { + .probe = rzn1_wdt_probe, + .driver = { + .name = KBUILD_MODNAME, + .of_match_table = rzn1_wdt_match, + }, +}; + +module_platform_driver(rzn1_wdt_driver); + +MODULE_DESCRIPTION("Renesas RZ/N1 hardware watchdog"); +MODULE_AUTHOR("Phil Edworthy "); +MODULE_LICENSE("GPL"); -- cgit v1.2.3