Hi Dave,
On 15 September 2015 at 16:38, Dave Young <dyoung@xxxxxxxxxx> wrote:
> On 08/25/15 at 01:01am, fu.wei@xxxxxxxxxx wrote:
>> From: Fu Wei <fu.wei@xxxxxxxxxx>
>>
>> This driver bases on linux kernel watchdog framework, and
>> use "pretimeout" in the framework. It supports getting timeout and
>> pretimeout from parameter and FDT at the driver init stage.
>> In first timeout, the interrupt routine run panic to save
>> system context.
>>
>> Signed-off-by: Fu Wei <fu.wei@xxxxxxxxxx>
>> ---
>> drivers/watchdog/Kconfig | 14 ++
>> drivers/watchdog/Makefile | 1 +
>> drivers/watchdog/sbsa_gwdt.c | 459 +++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 474 insertions(+)
>>
>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>> index 241fafd..b2734f0 100644
>> --- a/drivers/watchdog/Kconfig
>> +++ b/drivers/watchdog/Kconfig
>> @@ -173,6 +173,20 @@ config ARM_SP805_WATCHDOG
>> ARM Primecell SP805 Watchdog timer. This will reboot your system when
>> the timeout is reached.
>>
>> +config ARM_SBSA_WATCHDOG
>> + tristate "ARM SBSA Generic Watchdog"
>> + depends on ARM64
>> + depends on ARM_ARCH_TIMER
>> + select WATCHDOG_CORE
>> + help
>> + ARM SBSA Generic Watchdog. This watchdog has two Watchdog timeouts.
>> + The first timeout will trigger a panic; the second timeout will
>> + trigger a system reset.
>> + More details: ARM DEN0029B - Server Base System Architecture (SBSA)
>> +
>> + To compile this driver as module, choose M here: The module
>> + will be called sbsa_gwdt.
>> +
>> config AT91RM9200_WATCHDOG
>> tristate "AT91RM9200 watchdog"
>> depends on SOC_AT91RM9200 && MFD_SYSCON
>> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
>> index 59ea9a1..be8e7c5 100644
>> --- a/drivers/watchdog/Makefile
>> +++ b/drivers/watchdog/Makefile
>> @@ -30,6 +30,7 @@ obj-$(CONFIG_USBPCWATCHDOG) += pcwd_usb.o
>>
>> # ARM Architecture
>> obj-$(CONFIG_ARM_SP805_WATCHDOG) += sp805_wdt.o
>> +obj-$(CONFIG_ARM_SBSA_WATCHDOG) += sbsa_gwdt.o
>> obj-$(CONFIG_AT91RM9200_WATCHDOG) += at91rm9200_wdt.o
>> obj-$(CONFIG_AT91SAM9X_WATCHDOG) += at91sam9_wdt.o
>> obj-$(CONFIG_CADENCE_WATCHDOG) += cadence_wdt.o
>> diff --git a/drivers/watchdog/sbsa_gwdt.c b/drivers/watchdog/sbsa_gwdt.c
>> new file mode 100644
>> index 0000000..7ae45cc
>> --- /dev/null
>> +++ b/drivers/watchdog/sbsa_gwdt.c
>> @@ -0,0 +1,459 @@
>> +/*
>> + * SBSA(Server Base System Architecture) Generic Watchdog driver
>> + *
>> + * Copyright (c) 2015, Linaro Ltd.
>> + * Author: Fu Wei <fu.wei@xxxxxxxxxx>
>> + * Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License 2 as published
>> + * by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> + * GNU General Public License for more details.
>> + *
>> + * The SBSA Generic watchdog driver is compatible with the pretimeout
>> + * concept of Linux kernel.
>> + * The timeout and pretimeout are determined by WCV or WOR.
>> + * The first watch period is set by writing WCV directly, that can
>> + * support more than 10s timeout at the maximum system counter
>> + * frequency (400MHz).
>> + * When WS0 is triggered, the second watch period (pretimeout) is
>> + * determined by one of these registers:
>> + * (1)WOR: 32bit register, this gives a maximum watch period of
>> + * around 10s at the maximum system counter frequency. It's loaded
>> + * automatically by hardware.
>> + * (2)WCV: If the pretimeout value is greater then "max_wor_timeout",
>> + * it will be loaded in WS0 interrupt routine. If system is in
>> + * ws0_mode (reboot by kexec/kdump in panic with watchdog enabled
>> + * and WS0 == true), the ping operation will only reload WCV.
>
> Below is the field comment about ws0_mode, it says ws0_mode is only
> for rebooting in second stage timeout, but kexec/kdump can reboot in
> either first or second stage
Great thanks for your feedback.
yes, if kexec/kdump reboot the system before the WS0, ws0_mode may not be set.
in this case, if WS0 is triggered during the reboot(AFAIK, panic will
disable irq, and in the early boot stage of system, irq is disabled,
too.), ws0_mode will be set at the next "open" in kdump kernel
if WS0 haven't triggered until the watchdog is opened again in kdump
kernel , ws0_mode won't be set.
ws0_mode doesn't indicate if the system is in the kdump kernel, it
indicates that if WS0 is triggered, when the watchdog is initialized.
Do I answer your question?
> * @ws0_mode: indicate the system boot in the second stage timeout.
>
>
>> + * More details about the hardware specification of this device:
>> + * ARM DEN0029B - Server Base System Architecture (SBSA)
>> + *
>> + * Kernel/API: P------------------| pretimeout
>> + * |----------------------------------------T timeout
>> + * SBSA GWDT: P---WOR (or WCV)---WS1 pretimeout
>> + * |-------WCV----------WS0~~~(ws0_mode)~~~~T timeout
>> + */
>> +
>> +#include <linux/io.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/module.h>
>> +#include <linux/moduleparam.h>
>> +#include <linux/of.h>
>> +#include <linux/of_device.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/uaccess.h>
>> +#include <linux/watchdog.h>
>> +#include <asm/arch_timer.h>
>> +
>> +/* SBSA Generic Watchdog register definitions */
>> +/* refresh frame */
>> +#define SBSA_GWDT_WRR 0x000
>> +
>> +/* control frame */
>> +#define SBSA_GWDT_WCS 0x000
>> +#define SBSA_GWDT_WOR 0x008
>> +#define SBSA_GWDT_WCV_LO 0x010
>> +#define SBSA_GWDT_WCV_HI 0x014
>> +
>> +/* refresh/control frame */
>> +#define SBSA_GWDT_W_IIDR 0xfcc
>> +#define SBSA_GWDT_IDR 0xfd0
>> +
>> +/* Watchdog Control and Status Register */
>> +#define SBSA_GWDT_WCS_EN BIT(0)
>> +#define SBSA_GWDT_WCS_WS0 BIT(1)
>> +#define SBSA_GWDT_WCS_WS1 BIT(2)
>> +
>> +/**
>> + * struct sbsa_gwdt - Internal representation of the SBSA GWDT
>> + * @wdd: kernel watchdog_device structure
>> + * @clk: store the System Counter clock frequency, in Hz.
>> + * @ws0_mode: indicate the system boot in the second stage timeout.
>> + * @max_wor_timeout: the maximum timeout value for WOR (in seconds).
>> + * @refresh_base: Virtual address of the watchdog refresh frame
>> + * @control_base: Virtual address of the watchdog control frame
>> + */
>> +struct sbsa_gwdt {
>> + struct watchdog_device wdd;
>> + u32 clk;
>> + bool ws0_mode;
>> + int max_wor_timeout;
>> + void __iomem *refresh_base;
>> + void __iomem *control_base;
>> +};
>> +
>> +#define to_sbsa_gwdt(e) container_of(e, struct sbsa_gwdt, wdd)
>> +
>> +#define DEFAULT_TIMEOUT 30 /* seconds, the 1st + 2nd watch periods*/
>> +#define DEFAULT_PRETIMEOUT 10 /* seconds, the 2nd watch period*/
>> +
>> +static unsigned int timeout;
>> +module_param(timeout, uint, 0);
>> +MODULE_PARM_DESC(timeout,
>> + "Watchdog timeout in seconds. (>=0, default="
>> + __MODULE_STRING(DEFAULT_TIMEOUT) ")");
>> +
>> +static unsigned int pretimeout;
>> +module_param(pretimeout, uint, 0);
>> +MODULE_PARM_DESC(pretimeout,
>> + "Watchdog pretimeout in seconds. (>=0, default="
>> + __MODULE_STRING(DEFAULT_PRETIMEOUT) ")");
>> +
>> +static bool nowayout = WATCHDOG_NOWAYOUT;
>> +module_param(nowayout, bool, S_IRUGO);
>> +MODULE_PARM_DESC(nowayout,
>> + "Watchdog cannot be stopped once started (default="
>> + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
>> +
>> +/*
>> + * help functions for accessing 64bit WCV register
>> + */
>> +static u64 sbsa_gwdt_get_wcv(struct watchdog_device *wdd)
>> +{
>> + u32 wcv_lo, wcv_hi;
>> + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
>> +
>> + do {
>> + wcv_hi = readl_relaxed(gwdt->control_base + SBSA_GWDT_WCV_HI);
>> + wcv_lo = readl_relaxed(gwdt->control_base + SBSA_GWDT_WCV_LO);
>> + } while (wcv_hi != readl_relaxed(gwdt->control_base +
>> + SBSA_GWDT_WCV_HI));
>> +
>> + return (((u64)wcv_hi << 32) | wcv_lo);
>> +}
>> +
>> +static void sbsa_gwdt_set_wcv(struct watchdog_device *wdd, unsigned int t)
>> +{
>> + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
>> + u64 wcv;
>> +
>> + wcv = arch_counter_get_cntvct() + (u64)t * gwdt->clk;
>> +
>> + writel_relaxed(upper_32_bits(wcv),
>> + gwdt->control_base + SBSA_GWDT_WCV_HI);
>> + writel_relaxed(lower_32_bits(wcv),
>> + gwdt->control_base + SBSA_GWDT_WCV_LO);
>> +}
>> +
>> +/*
>> + * inline functions for reloading 64bit WCV register
>> + */
>> +static inline void reload_pretimeout_to_wcv(struct watchdog_device *wdd)
>> +{
>> + sbsa_gwdt_set_wcv(wdd, wdd->pretimeout);
>> +}
>> +
>> +static inline void reload_first_stage_to_wcv(struct watchdog_device *wdd)
>> +{
>> + sbsa_gwdt_set_wcv(wdd, wdd->timeout - wdd->pretimeout);
>> +}
>> +
>> +/*
>> + * watchdog operation functions
>> + */
>> +static int sbsa_gwdt_set_timeout(struct watchdog_device *wdd,
>> + unsigned int timeout)
>> +{
>> + wdd->timeout = timeout;
>> +
>> + return 0;
>> +}
>> +
>> +static int sbsa_gwdt_set_pretimeout(struct watchdog_device *wdd,
>> + unsigned int pretimeout)
>> +{
>> + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
>> + u32 wor;
>> +
>> + wdd->pretimeout = pretimeout;
>> +
>> + /* If ws0_mode == true, we won't touch WOR */
>> + if (!gwdt->ws0_mode) {
>> + if (!pretimeout)
>> + /*
>> + * If pretimeout is 0, it gives driver a timeslot (1s)
>> + * to update WCV after an explicit refresh
>> + * (sbsa_gwdt_start)
>> + */
>> + wor = gwdt->clk;
>> + else
>> + if (pretimeout > gwdt->max_wor_timeout)
>> + wor = U32_MAX;
>> + else
>> + wor = pretimeout * gwdt->clk;
>> +
>> + /* wtite WOR, that will cause an explicit watchdog refresh */
>> + writel_relaxed(wor, gwdt->control_base + SBSA_GWDT_WOR);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static unsigned int sbsa_gwdt_get_timeleft(struct watchdog_device *wdd)
>> +{
>> + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
>> + u64 timeleft = sbsa_gwdt_get_wcv(wdd) - arch_counter_get_cntvct();
>> +
>> + do_div(timeleft, gwdt->clk);
>> +
>> + return timeleft;
>> +}
>> +
>> +static int sbsa_gwdt_keepalive(struct watchdog_device *wdd)
>> +{
>> + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
>> +
>> + if (gwdt->ws0_mode)
>> + reload_pretimeout_to_wcv(wdd);
>> + else
>> + reload_first_stage_to_wcv(wdd);
>> +
>> + return 0;
>> +}
>> +
>> +static int sbsa_gwdt_start(struct watchdog_device *wdd)
>> +{
>> + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
>> +
>> + /* If ws0_mode == true, the watchdog is enabled */
>> + if (!gwdt->ws0_mode)
>> + /* writing WCS will cause an explicit watchdog refresh */
>> + writel_relaxed(SBSA_GWDT_WCS_EN,
>> + gwdt->control_base + SBSA_GWDT_WCS);
>> +
>> + return sbsa_gwdt_keepalive(wdd);
>> +}
>> +
>> +static int sbsa_gwdt_stop(struct watchdog_device *wdd)
>> +{
>> + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
>> +
>> + writel_relaxed(0, gwdt->control_base + SBSA_GWDT_WCS);
>> + /*
>> + * Writing WCS has caused an explicit watchdog refresh.
>> + * Both watchdog signals are deasserted, so clean ws0_mode flag.
>> + */
>> + gwdt->ws0_mode = false;
>> +
>> + return 0;
>> +}
>> +
>> +static irqreturn_t sbsa_gwdt_interrupt(int irq, void *dev_id)
>> +{
>> + struct sbsa_gwdt *gwdt = (struct sbsa_gwdt *)dev_id;
>> + struct watchdog_device *wdd = &gwdt->wdd;
>> +
>> + /* We don't use pretimeout, trigger WS1 now */
>> + if (!wdd->pretimeout)
>> + sbsa_gwdt_set_wcv(wdd, 0);
>> +
>> + /*
>> + * The pretimeout is valid, go panic
>> + * If pretimeout is greater then "max_wor_timeout",
>> + * reload the right value to WCV, then panic
>> + */
>> + if (wdd->pretimeout > gwdt->max_wor_timeout)
>> + reload_pretimeout_to_wcv(wdd);
>> + panic("SBSA Watchdog pre-timeout");
>> +
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static struct watchdog_info sbsa_gwdt_info = {
>> + .identity = "SBSA Generic Watchdog",
>> + .options = WDIOF_SETTIMEOUT |
>> + WDIOF_KEEPALIVEPING |
>> + WDIOF_MAGICCLOSE |
>> + WDIOF_PRETIMEOUT |
>> + WDIOF_CARDRESET,
>> +};
>> +
>> +static struct watchdog_ops sbsa_gwdt_ops = {
>> + .owner = THIS_MODULE,
>> + .start = sbsa_gwdt_start,
>> + .stop = sbsa_gwdt_stop,
>> + .ping = sbsa_gwdt_keepalive,
>> + .set_timeout = sbsa_gwdt_set_timeout,
>> + .set_pretimeout = sbsa_gwdt_set_pretimeout,
>> + .get_timeleft = sbsa_gwdt_get_timeleft,
>> +};
>> +
>> +static int sbsa_gwdt_probe(struct platform_device *pdev)
>> +{
>> + void __iomem *rf_base, *cf_base;
>> + struct device *dev = &pdev->dev;
>> + struct watchdog_device *wdd;
>> + struct sbsa_gwdt *gwdt;
>> + struct resource *res;
>> + int ret, irq;
>> + u32 status;
>> +
>> + gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL);
>> + if (!gwdt)
>> + return -ENOMEM;
>> + platform_set_drvdata(pdev, gwdt);
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + cf_base = devm_ioremap_resource(dev, res);
>> + if (IS_ERR(cf_base))
>> + return PTR_ERR(cf_base);
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
>> + rf_base = devm_ioremap_resource(dev, res);
>> + if (IS_ERR(rf_base))
>> + return PTR_ERR(rf_base);
>> +
>> + irq = platform_get_irq(pdev, 0);
>> + if (irq < 0) {
>> + dev_err(dev, "unable to get ws0 interrupt.\n");
>> + return irq;
>> + }
>> +
>> + /*
>> + * Get the frequency of system counter from the cp15 interface of ARM
>> + * Generic timer. We don't need to check it, because if it returns "0",
>> + * system would panic in very early stage.
>> + */
>> + gwdt->clk = arch_timer_get_cntfrq();
>> + gwdt->refresh_base = rf_base;
>> + gwdt->control_base = cf_base;
>> + gwdt->max_wor_timeout = U32_MAX / gwdt->clk;
>> + gwdt->ws0_mode = false;
>> +
>> + wdd = &gwdt->wdd;
>> + wdd->parent = dev;
>> + wdd->info = &sbsa_gwdt_info;
>> + wdd->ops = &sbsa_gwdt_ops;
>> + watchdog_set_drvdata(wdd, gwdt);
>> + watchdog_set_nowayout(wdd, nowayout);
>> +
>> + wdd->min_pretimeout = 0;
>> + wdd->min_timeout = 1;
>> +
>> + /*
>> + * Because the maximum of gwdt->clk is 400MHz and the maximum of WCV is
>> + * U64_MAX, so the result of (U64_MAX / gwdt->clk) is always greater
>> + * than U32_MAX. And the maximum of "unsigned int" is U32_MAX on ARM64.
>> + * So we set the maximum value of pretimeout and timeout below.
>> + */
>> + wdd->max_pretimeout = U32_MAX - 1;
>> + wdd->max_timeout = U32_MAX;
>> +
>> + wdd->pretimeout = DEFAULT_PRETIMEOUT;
>> + wdd->timeout = DEFAULT_TIMEOUT;
>> + watchdog_init_timeouts(wdd, pretimeout, timeout, dev);
>> +
>> + status = readl_relaxed(gwdt->control_base + SBSA_GWDT_WCS);
>> + if (status & SBSA_GWDT_WCS_WS1) {
>> + dev_warn(dev, "System reset by WDT.\n");
>> + wdd->bootstatus |= WDIOF_CARDRESET;
>> + } else if (status == (SBSA_GWDT_WCS_WS0 | SBSA_GWDT_WCS_EN)) {
>> + gwdt->ws0_mode = true;
>> + }
>> +
>> + ret = devm_request_irq(dev, irq, sbsa_gwdt_interrupt, 0,
>> + pdev->name, gwdt);
>> + if (ret) {
>> + dev_err(dev, "unable to request IRQ %d\n", irq);
>> + return ret;
>> + }
>> +
>> + ret = watchdog_register_device(wdd);
>> + if (ret)
>> + return ret;
>> +
>> + /* If ws0_mode == true, the line won't update WOR */
>> + sbsa_gwdt_set_pretimeout(wdd, wdd->pretimeout);
>> +
>> + /*
>> + * If watchdog is already enabled, do a ping operation
>> + * to keep system running
>> + */
>> + if (status & SBSA_GWDT_WCS_EN)
>> + sbsa_gwdt_keepalive(wdd);
>> +
>> + dev_info(dev, "Initialized with %ds timeout, %ds pretimeout @ %u Hz%s\n",
>> + wdd->timeout, wdd->pretimeout, gwdt->clk,
>> + status & SBSA_GWDT_WCS_EN ?
>> + gwdt->ws0_mode ? " [second stage]" : " [enabled]" :
>> + "");
>> +
>> + return 0;
>> +}
>> +
>> +static void sbsa_gwdt_shutdown(struct platform_device *pdev)
>> +{
>> + struct sbsa_gwdt *gwdt = platform_get_drvdata(pdev);
>> +
>> + sbsa_gwdt_stop(&gwdt->wdd);
>> +}
>> +
>> +static int sbsa_gwdt_remove(struct platform_device *pdev)
>> +{
>> + struct sbsa_gwdt *gwdt = platform_get_drvdata(pdev);
>> +
>> + watchdog_unregister_device(&gwdt->wdd);
>> +
>> + return 0;
>> +}
>> +
>> +/* Disable watchdog if it is active during suspend */
>> +static int __maybe_unused sbsa_gwdt_suspend(struct device *dev)
>> +{
>> + struct sbsa_gwdt *gwdt = dev_get_drvdata(dev);
>> +
>> + if (watchdog_active(&gwdt->wdd))
>> + sbsa_gwdt_stop(&gwdt->wdd);
>> +
>> + return 0;
>> +}
>> +
>> +/* Enable watchdog and configure it if necessary */
>> +static int __maybe_unused sbsa_gwdt_resume(struct device *dev)
>> +{
>> + struct sbsa_gwdt *gwdt = dev_get_drvdata(dev);
>> +
>> + if (watchdog_active(&gwdt->wdd))
>> + sbsa_gwdt_start(&gwdt->wdd);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct dev_pm_ops sbsa_gwdt_pm_ops = {
>> + SET_SYSTEM_SLEEP_PM_OPS(sbsa_gwdt_suspend, sbsa_gwdt_resume)
>> +};
>> +
>> +static const struct of_device_id sbsa_gwdt_of_match[] = {
>> + { .compatible = "arm,sbsa-gwdt", },
>> + {},
>> +};
>> +MODULE_DEVICE_TABLE(of, sbsa_gwdt_of_match);
>> +
>> +static const struct platform_device_id sbsa_gwdt_pdev_match[] = {
>> + { .name = "sbsa-gwdt", },
>> + {},
>> +};
>> +MODULE_DEVICE_TABLE(platform, sbsa_gwdt_pdev_match);
>> +
>> +static struct platform_driver sbsa_gwdt_driver = {
>> + .driver = {
>> + .name = "sbsa-gwdt",
>> + .pm = &sbsa_gwdt_pm_ops,
>> + .of_match_table = sbsa_gwdt_of_match,
>> + },
>> + .probe = sbsa_gwdt_probe,
>> + .remove = sbsa_gwdt_remove,
>> + .shutdown = sbsa_gwdt_shutdown,
>> + .id_table = sbsa_gwdt_pdev_match,
>> +};
>> +
>> +module_platform_driver(sbsa_gwdt_driver);
>> +
>> +MODULE_DESCRIPTION("SBSA Generic Watchdog Driver");
>> +MODULE_AUTHOR("Fu Wei <fu.wei@xxxxxxxxxx>");
>> +MODULE_AUTHOR("Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>");
>> +MODULE_LICENSE("GPL v2");
>> --
>> 2.4.3
>>
--
Best regards,
Fu Wei
Software Engineer
Red Hat Software (Beijing) Co.,Ltd.Shanghai Branch
Ph: +86 21 61221326(direct)
Ph: +86 186 2020 4684 (mobile)
Room 1512, Regus One Corporate Avenue,Level 15,
One Corporate Avenue,222 Hubin Road,Huangpu District,
Shanghai,China 200021
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