// SPDX-License-Identifier: GPL-2.0 /* * Renesas RZ/G2L WDT Watchdog Driver * * Copyright (C) 2021 Renesas Electronics Corporation */ #include #include #include #include #include #include #include #include #include #include #include #include #define WDTCNT 0x00 #define WDTSET 0x04 #define WDTTIM 0x08 #define WDTINT 0x0C #define WDTCNT_WDTEN BIT(0) #define WDTINT_INTDISP BIT(0) #define WDT_DEFAULT_TIMEOUT 60U /* Setting period time register only 12 bit set in WDTSET[31:20] */ #define WDTSET_COUNTER_MASK (0xFFF00000) #define WDTSET_COUNTER_VAL(f) ((f) << 20) #define F2CYCLE_NSEC(f) (1000000000 / (f)) 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) ")"); struct rzg2l_wdt_priv { void __iomem *base; struct watchdog_device wdev; struct reset_control *rstc; unsigned long osc_clk_rate; unsigned long delay; struct clk *pclk; struct clk *osc_clk; }; static void rzg2l_wdt_wait_delay(struct rzg2l_wdt_priv *priv) { /* delay timer when change the setting register */ ndelay(priv->delay); } static u32 rzg2l_wdt_get_cycle_usec(unsigned long cycle, u32 wdttime) { u64 timer_cycle_us = 1024 * 1024ULL * (wdttime + 1) * MICRO; return div64_ul(timer_cycle_us, cycle); } static void rzg2l_wdt_write(struct rzg2l_wdt_priv *priv, u32 val, unsigned int reg) { if (reg == WDTSET) val &= WDTSET_COUNTER_MASK; writel_relaxed(val, priv->base + reg); /* Registers other than the WDTINT is always synchronized with WDT_CLK */ if (reg != WDTINT) rzg2l_wdt_wait_delay(priv); } static void rzg2l_wdt_init_timeout(struct watchdog_device *wdev) { struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev); u32 time_out; /* Clear Lapsed Time Register and clear Interrupt */ rzg2l_wdt_write(priv, WDTINT_INTDISP, WDTINT); /* 2 consecutive overflow cycle needed to trigger reset */ time_out = (wdev->timeout * (MICRO / 2)) / rzg2l_wdt_get_cycle_usec(priv->osc_clk_rate, 0); rzg2l_wdt_write(priv, WDTSET_COUNTER_VAL(time_out), WDTSET); } static int rzg2l_wdt_start(struct watchdog_device *wdev) { struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev); pm_runtime_get_sync(wdev->parent); /* Initialize time out */ rzg2l_wdt_init_timeout(wdev); /* Initialize watchdog counter register */ rzg2l_wdt_write(priv, 0, WDTTIM); /* Enable watchdog timer*/ rzg2l_wdt_write(priv, WDTCNT_WDTEN, WDTCNT); return 0; } static int rzg2l_wdt_stop(struct watchdog_device *wdev) { struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev); pm_runtime_put(wdev->parent); reset_control_reset(priv->rstc); return 0; } static int rzg2l_wdt_restart(struct watchdog_device *wdev, unsigned long action, void *data) { struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev); /* Reset the module before we modify any register */ reset_control_reset(priv->rstc); clk_prepare_enable(priv->pclk); clk_prepare_enable(priv->osc_clk); /* smallest counter value to reboot soon */ rzg2l_wdt_write(priv, WDTSET_COUNTER_VAL(1), WDTSET); /* Enable watchdog timer*/ rzg2l_wdt_write(priv, WDTCNT_WDTEN, WDTCNT); return 0; } static const struct watchdog_info rzg2l_wdt_ident = { .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, .identity = "Renesas RZ/G2L WDT Watchdog", }; static int rzg2l_wdt_ping(struct watchdog_device *wdev) { struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev); rzg2l_wdt_write(priv, WDTINT_INTDISP, WDTINT); return 0; } static const struct watchdog_ops rzg2l_wdt_ops = { .owner = THIS_MODULE, .start = rzg2l_wdt_start, .stop = rzg2l_wdt_stop, .ping = rzg2l_wdt_ping, .restart = rzg2l_wdt_restart, }; static void rzg2l_wdt_reset_assert_pm_disable(void *data) { struct watchdog_device *wdev = data; struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev); pm_runtime_disable(wdev->parent); reset_control_assert(priv->rstc); } static int rzg2l_wdt_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct rzg2l_wdt_priv *priv; unsigned long pclk_rate; int ret; priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; priv->base = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(priv->base)) return PTR_ERR(priv->base); /* Get watchdog main clock */ priv->osc_clk = devm_clk_get(&pdev->dev, "oscclk"); if (IS_ERR(priv->osc_clk)) return dev_err_probe(&pdev->dev, PTR_ERR(priv->osc_clk), "no oscclk"); priv->osc_clk_rate = clk_get_rate(priv->osc_clk); if (!priv->osc_clk_rate) return dev_err_probe(&pdev->dev, -EINVAL, "oscclk rate is 0"); /* Get Peripheral clock */ priv->pclk = devm_clk_get(&pdev->dev, "pclk"); if (IS_ERR(priv->pclk)) return dev_err_probe(&pdev->dev, PTR_ERR(priv->pclk), "no pclk"); pclk_rate = clk_get_rate(priv->pclk); if (!pclk_rate) return dev_err_probe(&pdev->dev, -EINVAL, "pclk rate is 0"); priv->delay = F2CYCLE_NSEC(priv->osc_clk_rate) * 6 + F2CYCLE_NSEC(pclk_rate) * 9; priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL); if (IS_ERR(priv->rstc)) return dev_err_probe(&pdev->dev, PTR_ERR(priv->rstc), "failed to get cpg reset"); reset_control_deassert(priv->rstc); pm_runtime_enable(&pdev->dev); priv->wdev.info = &rzg2l_wdt_ident; priv->wdev.ops = &rzg2l_wdt_ops; priv->wdev.parent = dev; priv->wdev.min_timeout = 1; priv->wdev.max_timeout = rzg2l_wdt_get_cycle_usec(priv->osc_clk_rate, 0xfff) / USEC_PER_SEC; priv->wdev.timeout = WDT_DEFAULT_TIMEOUT; watchdog_set_drvdata(&priv->wdev, priv); ret = devm_add_action_or_reset(&pdev->dev, rzg2l_wdt_reset_assert_pm_disable, &priv->wdev); if (ret < 0) return ret; watchdog_set_nowayout(&priv->wdev, nowayout); watchdog_stop_on_unregister(&priv->wdev); ret = watchdog_init_timeout(&priv->wdev, 0, dev); if (ret) dev_warn(dev, "Specified timeout invalid, using default"); return devm_watchdog_register_device(&pdev->dev, &priv->wdev); } static const struct of_device_id rzg2l_wdt_ids[] = { { .compatible = "renesas,rzg2l-wdt", }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, rzg2l_wdt_ids); static struct platform_driver rzg2l_wdt_driver = { .driver = { .name = "rzg2l_wdt", .of_match_table = rzg2l_wdt_ids, }, .probe = rzg2l_wdt_probe, }; module_platform_driver(rzg2l_wdt_driver); MODULE_DESCRIPTION("Renesas RZ/G2L WDT Watchdog Driver"); MODULE_AUTHOR("Biju Das "); MODULE_LICENSE("GPL v2");