[LEDE-DEV] [PATCH] cns3xxx: restore mpcore watchdog

Koen Vandeputte koen.vandeputte at ncentric.com
Tue Jan 10 05:34:57 PST 2017


Adds the mpcore watchdog driver for kernel 4.4 as it was originally
present up to kernel 3.12

- Disabled by default for now, but can be simply enabled in kernelconfig
- Currently does not contain the latest patches as mentioned here:

https://git.kernel.org/cgit/linux/kernel/git/next/linux-
next.git/commit/?id=6e63a3a294fdf91eaaac1061a9c7a5f53d16ac25

Tested on cns3xxx (GW2388)

[    0.700000] mpcore_wdt: MPcore Watchdog Timer: 0.1. mpcore_noboot=0
mpcore_margin=60 sec (nowayout= 1)
[    3.490000] mpcore_wdt mpcore_wdt: enabling watchdog
[    3.490000] init: - watchdog -
[    8.750000] procd: - watchdog -

Signed-off-by: Koen Vandeputte <koen.vandeputte at ncentric.com>
---
 target/linux/cns3xxx/config-4.4                    |   1 +
 .../patches-4.4/300-restore-mpcore-watchdog.patch  | 502 +++++++++++++++++++++
 2 files changed, 503 insertions(+)
 create mode 100644 target/linux/cns3xxx/patches-4.4/300-restore-mpcore-watchdog.patch

diff --git a/target/linux/cns3xxx/config-4.4 b/target/linux/cns3xxx/config-4.4
index 4745f4e..ffc1f02 100644
--- a/target/linux/cns3xxx/config-4.4
+++ b/target/linux/cns3xxx/config-4.4
@@ -182,6 +182,7 @@ CONFIG_MMC_SDHCI_CNS3XXX=y
 CONFIG_MMC_SDHCI_PLTFM=y
 # CONFIG_MMC_TIFM_SD is not set
 CONFIG_MODULES_USE_ELF_REL=y
+# CONFIG_MPCORE_WATCHDOG is not set
 CONFIG_MTD_M25P80=y
 # CONFIG_MTD_OF_PARTS is not set
 CONFIG_MTD_PHYSMAP=y
diff --git a/target/linux/cns3xxx/patches-4.4/300-restore-mpcore-watchdog.patch b/target/linux/cns3xxx/patches-4.4/300-restore-mpcore-watchdog.patch
new file mode 100644
index 0000000..156dcaa
--- /dev/null
+++ b/target/linux/cns3xxx/patches-4.4/300-restore-mpcore-watchdog.patch
@@ -0,0 +1,502 @@
+--- a/Documentation/watchdog/watchdog-parameters.txt
++++ b/Documentation/watchdog/watchdog-parameters.txt
+@@ -196,6 +196,14 @@ reset: Watchdog Interrupt/Reset Mode. 0
+ nowayout: Watchdog cannot be stopped once started
+ 	(default=kernel config parameter)
+ -------------------------------------------------
++mpcore_wdt:
++mpcore_margin: MPcore timer margin in seconds.
++	(0 < mpcore_margin < 65536, default=60)
++nowayout: Watchdog cannot be stopped once started
++	(default=kernel config parameter)
++mpcore_noboot: MPcore watchdog action, set to 1 to ignore reboots,
++	0 to reboot (default=0
++--------------------------------------------------
+ mv64x60_wdt:
+ nowayout: Watchdog cannot be stopped once started
+ 	(default=kernel config parameter)
+--- a/drivers/watchdog/Kconfig
++++ b/drivers/watchdog/Kconfig
+@@ -297,6 +297,15 @@ config DW_WATCHDOG
+ 	  To compile this driver as a module, choose M here: the
+ 	  module will be called dw_wdt.
+ 
++config MPCORE_WATCHDOG
++	tristate "MPcore watchdog"
++	depends on HAVE_ARM_TWD
++	help
++	  Watchdog timer embedded into the MPcore system.
++
++	  To compile this driver as a module, choose M here: the
++	  module will be called mpcore_wdt.
++
+ config EP93XX_WATCHDOG
+ 	tristate "EP93xx Watchdog"
+ 	depends on ARCH_EP93XX
+--- a/drivers/watchdog/Makefile
++++ b/drivers/watchdog/Makefile
+@@ -43,6 +43,7 @@ obj-$(CONFIG_S3C2410_WATCHDOG) += s3c241
+ obj-$(CONFIG_SA1100_WATCHDOG) += sa1100_wdt.o
+ obj-$(CONFIG_SAMA5D4_WATCHDOG) += sama5d4_wdt.o
+ obj-$(CONFIG_DW_WATCHDOG) += dw_wdt.o
++obj-$(CONFIG_MPCORE_WATCHDOG) += mpcore_wdt.o
+ obj-$(CONFIG_EP93XX_WATCHDOG) += ep93xx_wdt.o
+ obj-$(CONFIG_PNX4008_WATCHDOG) += pnx4008_wdt.o
+ obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
+--- /dev/null
++++ b/drivers/watchdog/mpcore_wdt.c
+@@ -0,0 +1,454 @@
++/*
++ *	Watchdog driver for the mpcore watchdog timer
++ *
++ *	(c) Copyright 2004 ARM Limited
++ *
++ *	Based on the SoftDog driver:
++ *	(c) Copyright 1996 Alan Cox <alan at lxorguk.ukuu.org.uk>,
++ *						All Rights Reserved.
++ *
++ *	This program is free software; you can redistribute it and/or
++ *	modify it under the terms of the GNU General Public License
++ *	as published by the Free Software Foundation; either version
++ *	2 of the License, or (at your option) any later version.
++ *
++ *	Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
++ *	warranty for any of this software. This material is provided
++ *	"AS-IS" and at no charge.
++ *
++ *	(c) Copyright 1995    Alan Cox <alan at lxorguk.ukuu.org.uk>
++ *
++ */
++
++#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
++
++#include <linux/module.h>
++#include <linux/moduleparam.h>
++#include <linux/types.h>
++#include <linux/miscdevice.h>
++#include <linux/watchdog.h>
++#include <linux/fs.h>
++#include <linux/reboot.h>
++#include <linux/init.h>
++#include <linux/interrupt.h>
++#include <linux/platform_device.h>
++#include <linux/uaccess.h>
++#include <linux/slab.h>
++#include <linux/io.h>
++
++#include <asm/smp_twd.h>
++
++struct mpcore_wdt {
++	unsigned long	timer_alive;
++	struct device	*dev;
++	void __iomem	*base;
++	int		irq;
++	unsigned int	perturb;
++	char		expect_close;
++};
++
++static struct platform_device *mpcore_wdt_pdev;
++static DEFINE_SPINLOCK(wdt_lock);
++
++#define TIMER_MARGIN	60
++static int mpcore_margin = TIMER_MARGIN;
++module_param(mpcore_margin, int, 0);
++MODULE_PARM_DESC(mpcore_margin,
++	"MPcore timer margin in seconds. (0 < mpcore_margin < 65536, default="
++				__MODULE_STRING(TIMER_MARGIN) ")");
++
++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) ")");
++
++#define ONLY_TESTING	0
++static int mpcore_noboot = ONLY_TESTING;
++module_param(mpcore_noboot, int, 0);
++MODULE_PARM_DESC(mpcore_noboot, "MPcore watchdog action, "
++	"set to 1 to ignore reboots, 0 to reboot (default="
++					__MODULE_STRING(ONLY_TESTING) ")");
++
++/*
++ *	This is the interrupt handler.  Note that we only use this
++ *	in testing mode, so don't actually do a reboot here.
++ */
++static irqreturn_t mpcore_wdt_fire(int irq, void *arg)
++{
++	struct mpcore_wdt *wdt = arg;
++
++	/* Check it really was our interrupt */
++	if (readl(wdt->base + TWD_WDOG_INTSTAT)) {
++		dev_crit(wdt->dev, "Triggered - Reboot ignored\n");
++		/* Clear the interrupt on the watchdog */
++		writel(1, wdt->base + TWD_WDOG_INTSTAT);
++		return IRQ_HANDLED;
++	}
++	return IRQ_NONE;
++}
++
++/*
++ *	mpcore_wdt_keepalive - reload the timer
++ *
++ *	Note that the spec says a DIFFERENT value must be written to the reload
++ *	register each time.  The "perturb" variable deals with this by adding 1
++ *	to the count every other time the function is called.
++ */
++static void mpcore_wdt_keepalive(struct mpcore_wdt *wdt)
++{
++	unsigned long count;
++
++	spin_lock(&wdt_lock);
++	/* Assume prescale is set to 256 */
++	count =  __raw_readl(wdt->base + TWD_WDOG_COUNTER);
++	count = (0xFFFFFFFFU - count) * (HZ / 5);
++	count = (count / 256) * mpcore_margin;
++
++	/* Reload the counter */
++	writel(count + wdt->perturb, wdt->base + TWD_WDOG_LOAD);
++	wdt->perturb = wdt->perturb ? 0 : 1;
++	spin_unlock(&wdt_lock);
++}
++
++static void mpcore_wdt_stop(struct mpcore_wdt *wdt)
++{
++	spin_lock(&wdt_lock);
++	writel(0x12345678, wdt->base + TWD_WDOG_DISABLE);
++	writel(0x87654321, wdt->base + TWD_WDOG_DISABLE);
++	writel(0x0, wdt->base + TWD_WDOG_CONTROL);
++	spin_unlock(&wdt_lock);
++}
++
++static void mpcore_wdt_start(struct mpcore_wdt *wdt)
++{
++	dev_info(wdt->dev, "enabling watchdog\n");
++
++	/* This loads the count register but does NOT start the count yet */
++	mpcore_wdt_keepalive(wdt);
++
++	if (mpcore_noboot) {
++		/* Enable watchdog - prescale=256, watchdog mode=0, enable=1 */
++		writel(0x0000FF01, wdt->base + TWD_WDOG_CONTROL);
++	} else {
++		/* Enable watchdog - prescale=256, watchdog mode=1, enable=1 */
++		writel(0x0000FF09, wdt->base + TWD_WDOG_CONTROL);
++	}
++}
++
++static int mpcore_wdt_set_heartbeat(int t)
++{
++	if (t < 0x0001 || t > 0xFFFF)
++		return -EINVAL;
++
++	mpcore_margin = t;
++	return 0;
++}
++
++/*
++ *	/dev/watchdog handling
++ */
++static int mpcore_wdt_open(struct inode *inode, struct file *file)
++{
++	struct mpcore_wdt *wdt = platform_get_drvdata(mpcore_wdt_pdev);
++
++	if (test_and_set_bit(0, &wdt->timer_alive))
++		return -EBUSY;
++
++	if (nowayout)
++		__module_get(THIS_MODULE);
++
++	file->private_data = wdt;
++
++	/*
++	 *	Activate timer
++	 */
++	mpcore_wdt_start(wdt);
++
++	return nonseekable_open(inode, file);
++}
++
++static int mpcore_wdt_release(struct inode *inode, struct file *file)
++{
++	struct mpcore_wdt *wdt = file->private_data;
++
++	/*
++	 *	Shut off the timer.
++	 *	Lock it in if it's a module and we set nowayout
++	 */
++	if (wdt->expect_close == 42)
++		mpcore_wdt_stop(wdt);
++	else {
++		dev_crit(wdt->dev,
++			 "unexpected close, not stopping watchdog!\n");
++		mpcore_wdt_keepalive(wdt);
++	}
++	clear_bit(0, &wdt->timer_alive);
++	wdt->expect_close = 0;
++	return 0;
++}
++
++static ssize_t mpcore_wdt_write(struct file *file, const char *data,
++						size_t len, loff_t *ppos)
++{
++	struct mpcore_wdt *wdt = file->private_data;
++
++	/*
++	 *	Refresh the timer.
++	 */
++	if (len) {
++		if (!nowayout) {
++			size_t i;
++
++			/* In case it was set long ago */
++			wdt->expect_close = 0;
++
++			for (i = 0; i != len; i++) {
++				char c;
++
++				if (get_user(c, data + i))
++					return -EFAULT;
++				if (c == 'V')
++					wdt->expect_close = 42;
++			}
++		}
++		mpcore_wdt_keepalive(wdt);
++	}
++	return len;
++}
++
++static const struct watchdog_info ident = {
++	.options		= WDIOF_SETTIMEOUT |
++				  WDIOF_KEEPALIVEPING |
++				  WDIOF_MAGICCLOSE,
++	.identity		= "MPcore Watchdog",
++};
++
++static long mpcore_wdt_ioctl(struct file *file, unsigned int cmd,
++							unsigned long arg)
++{
++	struct mpcore_wdt *wdt = file->private_data;
++	int ret;
++	union {
++		struct watchdog_info ident;
++		int i;
++	} uarg;
++
++	if (_IOC_DIR(cmd) && _IOC_SIZE(cmd) > sizeof(uarg))
++		return -ENOTTY;
++
++	if (_IOC_DIR(cmd) & _IOC_WRITE) {
++		ret = copy_from_user(&uarg, (void __user *)arg, _IOC_SIZE(cmd));
++		if (ret)
++			return -EFAULT;
++	}
++
++	switch (cmd) {
++	case WDIOC_GETSUPPORT:
++		uarg.ident = ident;
++		ret = 0;
++		break;
++
++	case WDIOC_GETSTATUS:
++	case WDIOC_GETBOOTSTATUS:
++		uarg.i = 0;
++		ret = 0;
++		break;
++
++	case WDIOC_SETOPTIONS:
++		ret = -EINVAL;
++		if (uarg.i & WDIOS_DISABLECARD) {
++			mpcore_wdt_stop(wdt);
++			ret = 0;
++		}
++		if (uarg.i & WDIOS_ENABLECARD) {
++			mpcore_wdt_start(wdt);
++			ret = 0;
++		}
++		break;
++
++	case WDIOC_KEEPALIVE:
++		mpcore_wdt_keepalive(wdt);
++		ret = 0;
++		break;
++
++	case WDIOC_SETTIMEOUT:
++		ret = mpcore_wdt_set_heartbeat(uarg.i);
++		if (ret)
++			break;
++
++		mpcore_wdt_keepalive(wdt);
++		/* Fall */
++	case WDIOC_GETTIMEOUT:
++		uarg.i = mpcore_margin;
++		ret = 0;
++		break;
++
++	default:
++		return -ENOTTY;
++	}
++
++	if (ret == 0 && _IOC_DIR(cmd) & _IOC_READ) {
++		ret = copy_to_user((void __user *)arg, &uarg, _IOC_SIZE(cmd));
++		if (ret)
++			ret = -EFAULT;
++	}
++	return ret;
++}
++
++/*
++ *	System shutdown handler.  Turn off the watchdog if we're
++ *	restarting or halting the system.
++ */
++static void mpcore_wdt_shutdown(struct platform_device *pdev)
++{
++	struct mpcore_wdt *wdt = platform_get_drvdata(pdev);
++
++	if (system_state == SYSTEM_RESTART || system_state == SYSTEM_HALT)
++		mpcore_wdt_stop(wdt);
++}
++
++/*
++ *	Kernel Interfaces
++ */
++static const struct file_operations mpcore_wdt_fops = {
++	.owner		= THIS_MODULE,
++	.llseek		= no_llseek,
++	.write		= mpcore_wdt_write,
++	.unlocked_ioctl	= mpcore_wdt_ioctl,
++	.open		= mpcore_wdt_open,
++	.release	= mpcore_wdt_release,
++};
++
++static struct miscdevice mpcore_wdt_miscdev = {
++	.minor		= WATCHDOG_MINOR,
++	.name		= "watchdog",
++	.fops		= &mpcore_wdt_fops,
++};
++
++static int mpcore_wdt_probe(struct platform_device *pdev)
++{
++	struct mpcore_wdt *wdt;
++	struct resource *res;
++	int ret;
++
++	/* We only accept one device, and it must have an id of -1 */
++	if (pdev->id != -1)
++		return -ENODEV;
++
++	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
++	if (!res)
++		return -ENODEV;
++
++	wdt = devm_kzalloc(&pdev->dev, sizeof(struct mpcore_wdt), GFP_KERNEL);
++	if (!wdt)
++		return -ENOMEM;
++
++	wdt->dev = &pdev->dev;
++	wdt->irq = platform_get_irq(pdev, 0);
++	if (wdt->irq >= 0) {
++		ret = devm_request_irq(wdt->dev, wdt->irq, mpcore_wdt_fire, 0,
++				"mpcore_wdt", wdt);
++		if (ret) {
++			dev_err(wdt->dev,
++				"cannot register IRQ%d for watchdog\n",
++				wdt->irq);
++			return ret;
++		}
++	}
++
++	wdt->base = devm_ioremap(wdt->dev, res->start, resource_size(res));
++	if (!wdt->base)
++		return -ENOMEM;
++
++	mpcore_wdt_miscdev.parent = &pdev->dev;
++	ret = misc_register(&mpcore_wdt_miscdev);
++	if (ret) {
++		dev_err(wdt->dev,
++			"cannot register miscdev on minor=%d (err=%d)\n",
++			WATCHDOG_MINOR, ret);
++		return ret;
++	}
++
++	mpcore_wdt_stop(wdt);
++	platform_set_drvdata(pdev, wdt);
++	mpcore_wdt_pdev = pdev;
++
++	return 0;
++}
++
++static int mpcore_wdt_remove(struct platform_device *pdev)
++{
++	misc_deregister(&mpcore_wdt_miscdev);
++
++	mpcore_wdt_pdev = NULL;
++
++	return 0;
++}
++
++#ifdef CONFIG_PM
++static int mpcore_wdt_suspend(struct platform_device *pdev, pm_message_t msg)
++{
++	struct mpcore_wdt *wdt = platform_get_drvdata(pdev);
++	mpcore_wdt_stop(wdt);		/* Turn the WDT off */
++	return 0;
++}
++
++static int mpcore_wdt_resume(struct platform_device *pdev)
++{
++	struct mpcore_wdt *wdt = platform_get_drvdata(pdev);
++	/* re-activate timer */
++	if (test_bit(0, &wdt->timer_alive))
++		mpcore_wdt_start(wdt);
++	return 0;
++}
++#else
++#define mpcore_wdt_suspend	NULL
++#define mpcore_wdt_resume	NULL
++#endif
++
++/* work with hotplug and coldplug */
++MODULE_ALIAS("platform:mpcore_wdt");
++
++static struct platform_driver mpcore_wdt_driver = {
++	.probe		= mpcore_wdt_probe,
++	.remove		= mpcore_wdt_remove,
++	.suspend	= mpcore_wdt_suspend,
++	.resume		= mpcore_wdt_resume,
++	.shutdown	= mpcore_wdt_shutdown,
++	.driver		= {
++		.owner	= THIS_MODULE,
++		.name	= "mpcore_wdt",
++	},
++};
++
++static int __init mpcore_wdt_init(void)
++{
++	/*
++	 * Check that the margin value is within it's range;
++	 * if not reset to the default
++	 */
++	if (mpcore_wdt_set_heartbeat(mpcore_margin)) {
++		mpcore_wdt_set_heartbeat(TIMER_MARGIN);
++		pr_info("mpcore_margin value must be 0 < mpcore_margin < 65536, using %d\n",
++			TIMER_MARGIN);
++	}
++
++	pr_info("MPcore Watchdog Timer: 0.1. mpcore_noboot=%d mpcore_margin=%d sec (nowayout= %d)\n",
++		mpcore_noboot, mpcore_margin, nowayout);
++
++	return platform_driver_register(&mpcore_wdt_driver);
++}
++
++static void __exit mpcore_wdt_exit(void)
++{
++	platform_driver_unregister(&mpcore_wdt_driver);
++}
++
++module_init(mpcore_wdt_init);
++module_exit(mpcore_wdt_exit);
++
++MODULE_AUTHOR("ARM Limited");
++MODULE_DESCRIPTION("MPcore Watchdog Device Driver");
++MODULE_LICENSE("GPL");
++MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
-- 
2.7.4




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