On Mon, Nov 02, 2020 at 01:23:11PM +0800, vijayakannan.ayyathurai@xxxxxxxxx wrote:
> From: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@xxxxxxxxx>
>
> Intel Keembay Soc requires watchdog timer support.
> Add watchdog driver to enable this.
>
> Signed-off-by: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@xxxxxxxxx>
> Acked-by: Mark Gross <mgross@xxxxxxxxxxxxxxx>
> Acked-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> ---
> drivers/watchdog/Kconfig | 13 ++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/keembay_wdt.c | 293 +++++++++++++++++++++++++++++++++
> 3 files changed, 307 insertions(+)
> create mode 100644 drivers/watchdog/keembay_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index fd7968635e6d..f412cf2d0f1a 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -2163,4 +2163,17 @@ config USBPCWATCHDOG
>
> Most people will say N.
>
> +config KEEMBAY_WATCHDOG
> + tristate "Intel Keem Bay SoC non-secure watchdog"
> + depends on ARCH_KEEMBAY || (ARM64 && COMPILE_TEST)
> + select WATCHDOG_CORE
> + help
> + This option enable support for an In-secure watchdog timer driver for
> + Intel Keem Bay SoC. This WDT has a 32 bit timer and decrements in every
> + count unit. An interrupt will be triggered, when the count crosses
> + the thershold configured in the register.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called keembay_wdt.
> +
> endif # WATCHDOG
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 071a2e50be98..f6f9f434f407 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -146,6 +146,7 @@ obj-$(CONFIG_INTEL_MEI_WDT) += mei_wdt.o
> obj-$(CONFIG_NI903X_WDT) += ni903x_wdt.o
> obj-$(CONFIG_NIC7018_WDT) += nic7018_wdt.o
> obj-$(CONFIG_MLX_WDT) += mlx_wdt.o
> +obj-$(CONFIG_KEEMBAY_WATCHDOG) += keembay_wdt.o
>
> # M68K Architecture
> obj-$(CONFIG_M54xx_WATCHDOG) += m54xx_wdt.o
> diff --git a/drivers/watchdog/keembay_wdt.c b/drivers/watchdog/keembay_wdt.c
> new file mode 100644
> index 000000000000..889e43fb95ac
> --- /dev/null
> +++ b/drivers/watchdog/keembay_wdt.c
> @@ -0,0 +1,293 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Watchdog driver for Intel Keem Bay non-secure watchdog.
> + *
> + * Copyright (C) 2020 Intel Corporation
> + */
> +
> +#include <linux/arm-smccc.h>
> +#include <linux/bits.h>
> +#include <linux/clk.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/limits.h>
> +#include <linux/module.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/platform_device.h>
> +#include <linux/reboot.h>
> +#include <linux/watchdog.h>
> +
> +/* Non-secure watchdog register offsets */
> +#define TIM_WATCHDOG 0x0
> +#define TIM_WATCHDOG_INT_THRES 0x4
> +#define TIM_WDOG_EN 0x8
> +#define TIM_SAFE 0xc
> +
> +#define WDT_ISR_MASK GENMASK(9, 8)
> +#define WDT_ISR_CLEAR 0x8200ff18
> +#define WDT_UNLOCK 0xf1d0dead
> +#define WDT_LOAD_MAX U32_MAX
> +#define WDT_LOAD_MIN 1
> +#define WDT_TIMEOUT 5
> +
> +static unsigned int timeout = WDT_TIMEOUT;
> +module_param(timeout, int, 0);
> +MODULE_PARM_DESC(timeout, "Watchdog timeout period in seconds (default = "
> + __MODULE_STRING(WDT_TIMEOUT) ")");
> +
> +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 keembay_wdt {
> + struct watchdog_device wdd;
> + struct clk *clk;
> + unsigned int rate;
> + int to_irq;
> + int th_irq;
> + void __iomem *base;
> +};
> +
> +static inline u32 keembay_wdt_readl(struct keembay_wdt *wdt, u32 offset)
> +{
> + return readl(wdt->base + offset);
> +}
> +
> +static inline void keembay_wdt_writel(struct keembay_wdt *wdt,
> + u32 offset, u32 val)
> +{
> + writel(WDT_UNLOCK, wdt->base + TIM_SAFE);
> + writel(val, wdt->base + offset);
> +}
> +
> +static void keembay_wdt_set_timeout_reg(struct watchdog_device *wdog, bool ping)
> +{
> + struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
> + u32 th_val = 0;
> +
> + if (ping)
> + keembay_wdt_writel(wdt, TIM_WATCHDOG, wdog->timeout * wdt->rate);
> +
> + if (wdog->pretimeout)
> + th_val = wdog->timeout - wdog->pretimeout;
> +
> + keembay_wdt_writel(wdt, TIM_WATCHDOG_INT_THRES, th_val * wdt->rate);
> +
> + if (ping)
> + keembay_wdt_writel(wdt, TIM_WATCHDOG, wdog->timeout * wdt->rate);
> +}
> +
> +static int keembay_wdt_start(struct watchdog_device *wdog)
> +{
> + struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
> +
> + keembay_wdt_set_timeout_reg(wdog, 0);
The second parameter is bool, so please use true/false.
Anyway, why does starting the watchdog require setting the pretimeout
register, but not setting the timeout register ?
> + keembay_wdt_writel(wdt, TIM_WDOG_EN, 1);
> +
> + return 0;
> +}
> +
> +static int keembay_wdt_stop(struct watchdog_device *wdog)
> +{
> + struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
> +
> + keembay_wdt_writel(wdt, TIM_WDOG_EN, 0);
> +
> + return 0;
> +}
> +
> +static int keembay_wdt_ping(struct watchdog_device *wdog)
> +{
> + keembay_wdt_set_timeout_reg(wdog, 1);
Each ping requires setting the timeout twice, plus setting the
pretimeout ? Really ?
Is this document somewhere. I think I'll want to confirm this with
the specification. The TIM_WATCHDOG register seems to need a lot
of updates, and I'd like to have some confirmation that this is
really necessary.
> +
> + return 0;
> +}
> +
> +static int keembay_wdt_set_timeout(struct watchdog_device *wdog, u32 t)
> +{
> + u32 actual = min(t, wdog->max_timeout);
> +
min() is unnecessary.
> + wdog->timeout = actual;
> + keembay_wdt_set_timeout_reg(wdog, 0);
Why does setting the timeout require setting the pretimeout register,
but not setting the timeout register ?
> +
> + return 0;
> +}
> +
> +static int keembay_wdt_set_pretimeout(struct watchdog_device *wdog, u32 t)
> +{
> + if (t < wdog->min_timeout || t >= wdog->timeout)
> + return -EINVAL;
Validated by watchdog core.
> +
> + wdog->pretimeout = t;
> + keembay_wdt_set_timeout_reg(wdog, 0);
> +
> + return 0;
> +}
> +
> +static unsigned int keembay_wdt_get_timeleft(struct watchdog_device *wdog)
> +{
> + struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
> +
> + return keembay_wdt_readl(wdt, TIM_WATCHDOG) / wdt->rate;
> +}
> +
> +/*
> + * SMC call is used to clear the interrupt bits, because the TIM_GEN_CONFIG
> + * register is in the secure bank.
> + */
> +static irqreturn_t keembay_wdt_to_isr(int irq, void *dev_id)
> +{
> + struct keembay_wdt *wdt = dev_id;
> + struct arm_smccc_res res;
> +
> + keembay_wdt_writel(wdt, TIM_WATCHDOG, 1);
> + arm_smccc_smc(WDT_ISR_CLEAR, WDT_ISR_MASK, 0, 0, 0, 0, 0, 0, &res);
> + dev_crit(wdt->wdd.parent, "Intel Keem Bay non-sec wdt timeout.\n");
> + emergency_restart();
> +
> + return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t keembay_wdt_th_isr(int irq, void *dev_id)
> +{
> + struct keembay_wdt *wdt = dev_id;
> + struct arm_smccc_res res;
> + u32 th_val = 0;
> +
> + if (wdt->wdd.pretimeout)
> + th_val = wdt->wdd.timeout - wdt->wdd.pretimeout;
> +
> + keembay_wdt_writel(wdt, TIM_WATCHDOG, th_val * wdt->rate + 1);
> + arm_smccc_smc(WDT_ISR_CLEAR, WDT_ISR_MASK, 0, 0, 0, 0, 0, 0, &res);
> + dev_crit(wdt->wdd.parent, "Intel Keem Bay non-sec wdt pre-timeout.\n");
> + watchdog_notify_pretimeout(&wdt->wdd);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static const struct watchdog_info keembay_wdt_info = {
> + .identity = "Intel Keem Bay Watchdog Timer",
> + .options = WDIOF_SETTIMEOUT |
> + WDIOF_PRETIMEOUT |
> + WDIOF_MAGICCLOSE |
> + WDIOF_KEEPALIVEPING,
> +};
> +
> +static const struct watchdog_ops keembay_wdt_ops = {
> + .owner = THIS_MODULE,
> + .start = keembay_wdt_start,
> + .stop = keembay_wdt_stop,
> + .ping = keembay_wdt_ping,
> + .set_timeout = keembay_wdt_set_timeout,
> + .set_pretimeout = keembay_wdt_set_pretimeout,
> + .get_timeleft = keembay_wdt_get_timeleft,
> +};
> +
> +static int keembay_wdt_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct keembay_wdt *wdt;
> + int ret;
> +
> + 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);
> +
> + /* we do not need to enable the clock as it is enabled by default */
> + wdt->clk = devm_clk_get(dev, NULL);
> + if (IS_ERR(wdt->clk))
> + return dev_err_probe(dev, PTR_ERR(wdt->clk), "Failed to get clock\n");
> +
> + wdt->rate = clk_get_rate(wdt->clk);
> + if (!wdt->rate)
> + return dev_err_probe(dev, -EINVAL, "Failed to get clock rate\n");
> +
> + wdt->th_irq = platform_get_irq_byname(pdev, "threshold");
> + if (wdt->th_irq < 0)
> + return dev_err_probe(dev, wdt->th_irq, "Failed to get IRQ for threshold\n");
> +
> + ret = devm_request_irq(dev, wdt->th_irq, keembay_wdt_th_isr, 0,
> + "keembay-wdt", wdt);
> + if (ret)
> + return dev_err_probe(dev, ret, "Failed to request IRQ for threshold\n");
> +
> + wdt->to_irq = platform_get_irq_byname(pdev, "timeout");
> + if (wdt->to_irq < 0)
> + return dev_err_probe(dev, wdt->to_irq, "Failed to get IRQ for timeout\n");
> +
> + ret = devm_request_irq(dev, wdt->to_irq, keembay_wdt_to_isr, 0,
> + "keembay-wdt", wdt);
> + if (ret)
> + return dev_err_probe(dev, ret, "Failed to request IRQ for timeout\n");
> +
> + wdt->wdd.parent = dev;
> + wdt->wdd.info = &keembay_wdt_info;
> + wdt->wdd.ops = &keembay_wdt_ops;
> + wdt->wdd.min_timeout = WDT_LOAD_MIN;
> + wdt->wdd.max_timeout = WDT_LOAD_MAX / wdt->rate;
> + wdt->wdd.timeout = WDT_TIMEOUT;
> +
> + watchdog_set_drvdata(&wdt->wdd, wdt);
> + watchdog_set_nowayout(&wdt->wdd, nowayout);
> + watchdog_init_timeout(&wdt->wdd, timeout, dev);
> + keembay_wdt_set_timeout(&wdt->wdd, wdt->wdd.timeout);
> +
> + ret = watchdog_register_device(&wdt->wdd);
> + if (ret)
> + return dev_err_probe(dev, ret, "Failed to register watchdog device.\n");
> +
> + platform_set_drvdata(pdev, wdt);
> + dev_info(dev, "Initial timeout %d sec%s.\n",
> + wdt->wdd.timeout, nowayout ? ", nowayout" : "");
> +
> + return 0;
> +}
> +
> +static int __maybe_unused keembay_wdt_suspend(struct device *dev)
> +{
> + struct keembay_wdt *wdt = dev_get_drvdata(dev);
> +
> + if (watchdog_active(&wdt->wdd))
> + return keembay_wdt_stop(&wdt->wdd);
> +
> + return 0;
> +}
> +
> +static int __maybe_unused keembay_wdt_resume(struct device *dev)
> +{
> + struct keembay_wdt *wdt = dev_get_drvdata(dev);
> +
> + if (watchdog_active(&wdt->wdd))
> + return keembay_wdt_start(&wdt->wdd);
> +
> + return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(keembay_wdt_pm_ops, keembay_wdt_suspend,
> + keembay_wdt_resume);
> +
> +static const struct of_device_id keembay_wdt_match[] = {
> + { .compatible = "intel,keembay-wdt" },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, keembay_wdt_match);
> +
> +static struct platform_driver keembay_wdt_driver = {
> + .probe = keembay_wdt_probe,
No remove function ? What happens if someone unloads
the driver ?
> + .driver = {
> + .name = "keembay_wdt",
> + .of_match_table = keembay_wdt_match,
> + .pm = &keembay_wdt_pm_ops,
> + },
> +};
> +
> +module_platform_driver(keembay_wdt_driver);
> +
> +MODULE_DESCRIPTION("Intel Keem Bay SoC watchdog driver");
> +MODULE_AUTHOR("Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@xxxxxxxxx");
> +MODULE_LICENSE("GPL v2");
> --
> 2.17.1
>
