diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/watchdog/rzg2l_wdt.c | 334 |
1 files changed, 334 insertions, 0 deletions
diff --git a/drivers/watchdog/rzg2l_wdt.c b/drivers/watchdog/rzg2l_wdt.c new file mode 100644 index 000000000..d404953d0 --- /dev/null +++ b/drivers/watchdog/rzg2l_wdt.c @@ -0,0 +1,334 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Renesas RZ/G2L WDT Watchdog Driver + * + * Copyright (C) 2021 Renesas Electronics Corporation + */ +#include <linux/bitops.h> +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/reset.h> +#include <linux/units.h> +#include <linux/watchdog.h> + +#define WDTCNT 0x00 +#define WDTSET 0x04 +#define WDTTIM 0x08 +#define WDTINT 0x0C +#define PECR 0x10 +#define PEEN 0x14 +#define WDTCNT_WDTEN BIT(0) +#define WDTINT_INTDISP BIT(0) +#define PEEN_FORCE 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)) + +#define RZV2M_A_NSEC 730 + +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) ")"); + +enum rz_wdt_type { + WDT_RZG2L, + WDT_RZV2M, +}; + +struct rzg2l_wdt_priv { + void __iomem *base; + struct watchdog_device wdev; + struct reset_control *rstc; + unsigned long osc_clk_rate; + unsigned long delay; + unsigned long minimum_assertion_period; + struct clk *pclk; + struct clk *osc_clk; + enum rz_wdt_type devtype; +}; + +static int rzg2l_wdt_reset(struct rzg2l_wdt_priv *priv) +{ + int err, status; + + if (priv->devtype == WDT_RZV2M) { + /* WDT needs TYPE-B reset control */ + err = reset_control_assert(priv->rstc); + if (err) + return err; + ndelay(priv->minimum_assertion_period); + err = reset_control_deassert(priv->rstc); + if (err) + return err; + err = read_poll_timeout(reset_control_status, status, + status != 1, 0, 1000, false, + priv->rstc); + } else { + err = reset_control_reset(priv->rstc); + } + + return err; +} + +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); + + rzg2l_wdt_reset(priv); + pm_runtime_put(wdev->parent); + + return 0; +} + +static int rzg2l_wdt_set_timeout(struct watchdog_device *wdev, unsigned int timeout) +{ + wdev->timeout = timeout; + + /* + * If the watchdog is active, reset the module for updating the WDTSET + * register by calling rzg2l_wdt_stop() (which internally calls reset_control_reset() + * to reset the module) so that it is updated with new timeout values. + */ + if (watchdog_active(wdev)) { + rzg2l_wdt_stop(wdev); + rzg2l_wdt_start(wdev); + } + + 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); + + clk_prepare_enable(priv->pclk); + clk_prepare_enable(priv->osc_clk); + + if (priv->devtype == WDT_RZG2L) { + /* Generate Reset (WDTRSTB) Signal on parity error */ + rzg2l_wdt_write(priv, 0, PECR); + + /* Force parity error */ + rzg2l_wdt_write(priv, PEEN_FORCE, PEEN); + } else { + /* RZ/V2M doesn't have parity error registers */ + rzg2l_wdt_reset(priv); + + wdev->timeout = 0; + + /* 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); + + /* Wait 2 consecutive overflow cycles for reset */ + mdelay(DIV_ROUND_UP(2 * 0xFFFFF * 1000, priv->osc_clk_rate)); + } + + 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, + .set_timeout = rzg2l_wdt_set_timeout, + .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"); + + ret = reset_control_deassert(priv->rstc); + if (ret) + return dev_err_probe(dev, ret, "failed to deassert"); + + priv->devtype = (uintptr_t)of_device_get_match_data(dev); + + if (priv->devtype == WDT_RZV2M) { + priv->minimum_assertion_period = RZV2M_A_NSEC + + 3 * F2CYCLE_NSEC(pclk_rate) + 5 * + max(F2CYCLE_NSEC(priv->osc_clk_rate), + F2CYCLE_NSEC(pclk_rate)); + } + + 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", .data = (void *)WDT_RZG2L }, + { .compatible = "renesas,rzv2m-wdt", .data = (void *)WDT_RZV2M }, + { /* 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 <biju.das.jz@bp.renesas.com>"); +MODULE_LICENSE("GPL v2"); |