Re: [PATCH v3 5/5] watchdog: Add Renesas RZ/N1 Watchdog driver

[Jean-Jacques Hiblot]

Hi Geert, Guenter,

What is the status of this patch ? There has been no comment on v3, I
had hoped it could go in the next version.
Thanks,
Jean-Jacques


Le lun. 21 févr. 2022 à 10:51, Jean-Jacques Hiblot
<jjhiblot@xxxxxxxxxxxxxxx> a écrit :

>
> From: Phil Edworthy <phil.edworthy@xxxxxxxxxxx>
>
> This is a driver for the standard WDT on the RZ/N1 devices. This WDT has
> very limited timeout capabilities. However, it can reset the device.
> To do so, the corresponding bits in the SysCtrl RSTEN register need to
> be enabled. This is not done by this driver.
>
> Signed-off-by: Phil Edworthy <phil.edworthy@xxxxxxxxxxx>
> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@xxxxxxxxxxxxxxx>
> ---
>  drivers/watchdog/Kconfig    |   8 ++
>  drivers/watchdog/Makefile   |   1 +
>  drivers/watchdog/rzn1_wdt.c | 206 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 215 insertions(+)
>  create mode 100644 drivers/watchdog/rzn1_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index c8fa79da23b3..ba6e4ebef404 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -883,6 +883,14 @@ config RENESAS_RZAWDT
>           This driver adds watchdog support for the integrated watchdogs in the
>           Renesas RZ/A SoCs. These watchdogs can be used to reset a system.
>
> +config RENESAS_RZN1WDT
> +       tristate "Renesas RZ/N1 watchdog"
> +       depends on ARCH_RENESAS || COMPILE_TEST
> +       select WATCHDOG_CORE
> +       help
> +         This driver adds watchdog support for the integrated watchdogs in the
> +         Renesas RZ/N1 SoCs. These watchdogs can be used to reset a system.
> +
>  config RENESAS_RZG2LWDT
>         tristate "Renesas RZ/G2L WDT Watchdog"
>         depends on ARCH_RENESAS || COMPILE_TEST
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index f7da867e8782..38d38564f47b 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -84,6 +84,7 @@ obj-$(CONFIG_LPC18XX_WATCHDOG) += lpc18xx_wdt.o
>  obj-$(CONFIG_BCM7038_WDT) += bcm7038_wdt.o
>  obj-$(CONFIG_RENESAS_WDT) += renesas_wdt.o
>  obj-$(CONFIG_RENESAS_RZAWDT) += rza_wdt.o
> +obj-$(CONFIG_RENESAS_RZN1WDT) += rzn1_wdt.o
>  obj-$(CONFIG_RENESAS_RZG2LWDT) += rzg2l_wdt.o
>  obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o
>  obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o
> diff --git a/drivers/watchdog/rzn1_wdt.c b/drivers/watchdog/rzn1_wdt.c
> new file mode 100644
> index 000000000000..7f5884e5d460
> --- /dev/null
> +++ b/drivers/watchdog/rzn1_wdt.c
> @@ -0,0 +1,206 @@
> +// 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 <linux/clk.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/platform_device.h>
> +#include <linux/watchdog.h>
> +
> +#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          wdt;
> +       void __iomem                    *base;
> +       unsigned long                   clk_rate;
> +};
> +
> +#define to_rzn1_watchdog(_ptr) \
> +       container_of(_ptr, struct rzn1_watchdog, wdt)
> +
> +static inline uint32_t get_max_heart_beat(unsigned long clk_rate)
> +{
> +       return (RZN1_WDT_MAX * RZN1_WDT_PRESCALER) / (clk_rate / 1000);
> +}
> +
> +static inline uint32_t compute_reload_value(uint32_t tick_ms,
> +                                           unsigned long clk_rate)
> +{
> +       return (tick_ms * (clk_rate / 1000)) / RZN1_WDT_PRESCALER;
> +}
> +
> +static int rzn1_wdt_ping(struct watchdog_device *w)
> +{
> +       struct rzn1_watchdog *wdt = to_rzn1_watchdog(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 = to_rzn1_watchdog(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);
> +       writel(val, wdt->base + RZN1_WDT_RETRIGGER);
> +
> +       return 0;
> +}
> +
> +static irqreturn_t rzn1_wdt_irq(int irq, void *_wdt)
> +{
> +       struct rzn1_watchdog *wdt = (struct rzn1_watchdog *)_wdt;
> +
> +       dev_info(wdt->wdt.parent, "%s triggered\n", __func__);
> +       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 const struct watchdog_device rzn1_wdt = {
> +       .info = &rzn1_wdt_info,
> +       .ops = &rzn1_wdt_ops,
> +       .status = WATCHDOG_NOWAYOUT_INIT_STATUS,
> +};
> +
> +static void rzn1_wdt_clk_disable_unprepare(void *data)
> +{
> +       clk_disable_unprepare(data);
> +}
> +
> +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;
> +       int ret;
> +       int irq;
> +
> +       wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
> +       if (!wdt)
> +               return -ENOMEM;
> +
> +       wdt->wdt = rzn1_wdt;
> +       wdt->wdt.parent = dev;
> +
> +       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(dev, NULL);
> +       if (IS_ERR(clk)) {
> +               dev_err(dev, "failed to get the clock\n");
> +               return PTR_ERR(clk);
> +       }
> +
> +       ret = clk_prepare_enable(clk);
> +       if (ret) {
> +               dev_err(dev, "failed to prepare/enable the clock\n");
> +               return ret;
> +       }
> +
> +       ret = devm_add_action_or_reset(dev, rzn1_wdt_clk_disable_unprepare,
> +                                      clk);
> +       if (ret) {
> +               dev_err(dev, "failed to register clock unprepare callback\n");
> +               return ret;
> +       }
> +
> +       wdt->clk_rate = clk_get_rate(clk);
> +       if (!wdt->clk_rate) {
> +               dev_err(dev, "failed to get the clock rate\n");
> +               return -EINVAL;
> +       }
> +
> +       /*
> +        * 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->wdt.max_hw_heartbeat_ms = get_max_heart_beat(wdt->clk_rate);
> +       if (wdt->wdt.max_hw_heartbeat_ms > 1000)
> +               wdt->wdt.max_hw_heartbeat_ms = 1000;
> +
> +       wdt->wdt.timeout = DEFAULT_TIMEOUT;
> +       ret = watchdog_init_timeout(&wdt->wdt, 0, dev);
> +
> +       return devm_watchdog_register_device(dev, &wdt->wdt);
> +}
> +
> +
> +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 <phil.edworthy@xxxxxxxxxxx>");
> +MODULE_LICENSE("GPL v2");
> --
> 2.25.1
>