Patchwork [1/2] watchdog: Basic support for GE Fanuc's FPGA based watchdog timer

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Submitter Martyn Welch
Date Nov. 10, 2008, 12:31 p.m.
Message ID <20081110123125.8608.2251.stgit@ubuntu8041.localdomain>
Download mbox | patch
Permalink /patch/8003/
State Accepted, archived
Delegated to: Kumar Gala
Headers show

Comments

Martyn Welch - Nov. 10, 2008, 12:31 p.m.
GE Fanuc SBC610

Support for the FPGA based watchdog timer as found on GE Fanuc's SBC310,
SBC610 and PPC9A Single Board Computers.

This patch adds support for the watchdog timer found in one of the devices
FPGAs. There are two identical watchdog timers at different offsets in the
above mentioned boards, this driver is capable of supporting one of them.
The watchdog timers are also capable of generating interrupts at a
user-configurable threshold, though support for this operation is currently
not supported by the driver.

Signed-off-by: Martyn Welch <martyn.welch@gefanuc.com>
---

 drivers/watchdog/Kconfig   |    6 +
 drivers/watchdog/Makefile  |    1 
 drivers/watchdog/gef_wdt.c |  333 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 340 insertions(+), 0 deletions(-)
Kumar Gala - Jan. 7, 2009, 4:27 a.m.
On Nov 10, 2008, at 6:31 AM, Martyn Welch wrote:

> GE Fanuc SBC610
>
> Support for the FPGA based watchdog timer as found on GE Fanuc's  
> SBC310,
> SBC610 and PPC9A Single Board Computers.
>
> This patch adds support for the watchdog timer found in one of the  
> devices
> FPGAs. There are two identical watchdog timers at different offsets  
> in the
> above mentioned boards, this driver is capable of supporting one of  
> them.
> The watchdog timers are also capable of generating interrupts at a
> user-configurable threshold, though support for this operation is  
> currently
> not supported by the driver.
>
> Signed-off-by: Martyn Welch <martyn.welch@gefanuc.com>
> ---
>
> drivers/watchdog/Kconfig   |    6 +
> drivers/watchdog/Makefile  |    1
> drivers/watchdog/gef_wdt.c |  333 +++++++++++++++++++++++++++++++++++ 
> +++++++++
> 3 files changed, 340 insertions(+), 0 deletions(-)

Wim,

Any status of acceptance of this?

- k
Wim Van Sebroeck - Jan. 7, 2009, 7:56 a.m.
Hi Kumar,

> >drivers/watchdog/Kconfig   |    6 +
> >drivers/watchdog/Makefile  |    1
> >drivers/watchdog/gef_wdt.c |  333 +++++++++++++++++++++++++++++++++++ 
> >+++++++++
> >3 files changed, 340 insertions(+), 0 deletions(-)
> 
> Wim,
> 
> Any status of acceptance of this?

I started reviewing it on sunday. It looks OK so you can expect inclusion in my -next tree this week.
A couple of days later I would like to forward it to Linus for mainline inclusion. It would like to have it in 2.6.29.

Kind regards,
Wim.
Wim Van Sebroeck - Jan. 7, 2009, 9:48 p.m.
Hi All,

> Any status of acceptance of this?

I changed the ioctl to an unlocked ioctl and removed the temperature ioctl call.
It's now in my linux-2.6-watchdog-next tree. Can someone verify that it still works?
(http://git.kernel.org/?p=linux/kernel/git/wim/linux-2.6-watchdog-next.git;a=summary)

Kumar,

the second patch is also in. Do we keep in in the watchdog tree since it almost doesn't
touch the powerpc arch or do you want it in your tree?

Kind regards,
Wim.
Kumar Gala - Jan. 7, 2009, 9:50 p.m.
On Jan 7, 2009, at 3:48 PM, Wim Van Sebroeck wrote:

> Hi All,
>
>> Any status of acceptance of this?
>
> I changed the ioctl to an unlocked ioctl and removed the temperature  
> ioctl call.
> It's now in my linux-2.6-watchdog-next tree. Can someone verify that  
> it still works?
> (http://git.kernel.org/?p=linux/kernel/git/wim/linux-2.6-watchdog-next.git;a=summary 
> )
>
> Kumar,
>
> the second patch is also in. Do we keep in in the watchdog tree  
> since it almost doesn't
> touch the powerpc arch or do you want it in your tree?

If you have it in your tree to pull go ahead and send it via  
watchdog.  (I assume this will be for 2.6.29)

- k
Wim Van Sebroeck - Jan. 7, 2009, 10:12 p.m.
Hi Kumar,

> >the second patch is also in. Do we keep in in the watchdog tree  
> >since it almost doesn't
> >touch the powerpc arch or do you want it in your tree?
> 
> If you have it in your tree to pull go ahead and send it via  
> watchdog.  (I assume this will be for 2.6.29)

Ok. Will do it like that. And yes it is for 2.6.29.

Kind regards,
Wim.
Martyn Welch - Jan. 8, 2009, 10:06 a.m.
Wim Van Sebroeck wrote:
> Hi All,
> 
>> Any status of acceptance of this?
> 
> I changed the ioctl to an unlocked ioctl and removed the temperature ioctl call.
> It's now in my linux-2.6-watchdog-next tree. Can someone verify that it still works?
> (http://git.kernel.org/?p=linux/kernel/git/wim/linux-2.6-watchdog-next.git;a=summary)
> 

Hi Wim,

Thank you for reviewing these patches. I have made the changes you have on my dev tree and, whilst I don't have an SBC610 to hand, I have checked the driver on a similar board which also uses the same watchdog and it's still working as expected.

Martyn

Patch

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 1a22fe7..df91e88 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -778,6 +778,12 @@  config BOOKE_WDT
 	  Please see Documentation/watchdog/watchdog-api.txt for
 	  more information.
 
+config GEF_WDT
+	tristate "GE Fanuc Watchdog Timer"
+	depends on GEF_SBC610
+	---help---
+	  Watchdog timer found in a number of GE Fanuc single board computers.
+
 # PPC64 Architecture
 
 config WATCHDOG_RTAS
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index e352bbb..be7e1d3 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -114,6 +114,7 @@  obj-$(CONFIG_MPC5200_WDT) += mpc5200_wdt.o
 obj-$(CONFIG_8xxx_WDT) += mpc8xxx_wdt.o
 obj-$(CONFIG_MV64X60_WDT) += mv64x60_wdt.o
 obj-$(CONFIG_BOOKE_WDT) += booke_wdt.o
+obj-$(CONFIG_GEF_WDT) += gef_wdt.o
 
 # PPC64 Architecture
 obj-$(CONFIG_WATCHDOG_RTAS) += wdrtas.o
diff --git a/drivers/watchdog/gef_wdt.c b/drivers/watchdog/gef_wdt.c
new file mode 100644
index 0000000..f82ef9c
--- /dev/null
+++ b/drivers/watchdog/gef_wdt.c
@@ -0,0 +1,333 @@ 
+/*
+ * GE Fanuc watchdog userspace interface
+ *
+ * Author:  Martyn Welch <martyn.welch@gefanuc.com>
+ *
+ * Copyright 2008 GE Fanuc Intelligent Platforms Embedded Systems, Inc.
+ *
+ * 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.
+ *
+ * Based on: mv64x60_wdt.c (MV64X60 watchdog userspace interface)
+ *   Author: James Chapman <jchapman@katalix.com>
+ */
+
+/* TODO:
+ * This driver does not provide support for the hardwares capability of sending
+ * an interrupt at a programmable threshold.
+ *
+ * This driver currently can only support 1 watchdog - there are 2 in the
+ * hardware that this driver supports. Thus one could be configured as a
+ * process-based watchdog (via /dev/watchdog), the second (using the interrupt
+ * capabilities) a kernel-based watchdog.
+ */
+
+#include <linux/kernel.h>
+#include <linux/compiler.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+
+#include <sysdev/fsl_soc.h>
+
+/*
+ * The watchdog configuration register contains a pair of 2-bit fields,
+ *   1.  a reload field, bits 27-26, which triggers a reload of
+ *       the countdown register, and
+ *   2.  an enable field, bits 25-24, which toggles between
+ *       enabling and disabling the watchdog timer.
+ * Bit 31 is a read-only field which indicates whether the
+ * watchdog timer is currently enabled.
+ *
+ * The low 24 bits contain the timer reload value.
+ */
+#define GEF_WDC_ENABLE_SHIFT	24
+#define GEF_WDC_SERVICE_SHIFT	26
+#define GEF_WDC_ENABLED_SHIFT	31
+
+#define GEF_WDC_ENABLED_TRUE	1
+#define GEF_WDC_ENABLED_FALSE	0
+
+/* Flags bits */
+#define GEF_WDOG_FLAG_OPENED	0
+
+static unsigned long wdt_flags;
+static int wdt_status;
+static void __iomem *gef_wdt_regs;
+static int gef_wdt_timeout;
+static int gef_wdt_count;
+static unsigned int bus_clk;
+static char expect_close;
+static DEFINE_SPINLOCK(gef_wdt_spinlock);
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+
+static int gef_wdt_toggle_wdc(int enabled_predicate, int field_shift)
+{
+	u32 data;
+	u32 enabled;
+	int ret = 0;
+
+	spin_lock(&gef_wdt_spinlock);
+	data = ioread32be(gef_wdt_regs);
+	enabled = (data >> GEF_WDC_ENABLED_SHIFT) & 1;
+
+	/* only toggle the requested field if enabled state matches predicate */
+	if ((enabled ^ enabled_predicate) == 0) {
+		/* We write a 1, then a 2 -- to the appropriate field */
+		data = (1 << field_shift) | gef_wdt_count;
+		iowrite32be(data, gef_wdt_regs);
+
+		data = (2 << field_shift) | gef_wdt_count;
+		iowrite32be(data, gef_wdt_regs);
+		ret = 1;
+	}
+	spin_unlock(&gef_wdt_spinlock);
+
+	return ret;
+}
+
+static void gef_wdt_service(void)
+{
+	gef_wdt_toggle_wdc(GEF_WDC_ENABLED_TRUE,
+		GEF_WDC_SERVICE_SHIFT);
+}
+
+static void gef_wdt_handler_enable(void)
+{
+	if (gef_wdt_toggle_wdc(GEF_WDC_ENABLED_FALSE,
+				   GEF_WDC_ENABLE_SHIFT)) {
+		gef_wdt_service();
+		printk(KERN_NOTICE "gef_wdt: watchdog activated\n");
+	}
+}
+
+static void gef_wdt_handler_disable(void)
+{
+	if (gef_wdt_toggle_wdc(GEF_WDC_ENABLED_TRUE,
+				   GEF_WDC_ENABLE_SHIFT))
+		printk(KERN_NOTICE "gef_wdt: watchdog deactivated\n");
+}
+
+static void gef_wdt_set_timeout(unsigned int timeout)
+{
+	/* maximum bus cycle count is 0xFFFFFFFF */
+	if (timeout > 0xFFFFFFFF / bus_clk)
+		timeout = 0xFFFFFFFF / bus_clk;
+
+	/* Register only holds upper 24 bits, bit shifted into lower 24 */
+	gef_wdt_count = (timeout * bus_clk) >> 8;
+	gef_wdt_timeout = timeout;
+}
+
+
+static ssize_t gef_wdt_write(struct file *file, const char __user *data,
+				 size_t len, loff_t *ppos)
+{
+	if (len) {
+		if (!nowayout) {
+			size_t i;
+
+			expect_close = 0;
+
+			for (i = 0; i != len; i++) {
+				char c;
+				if (get_user(c, data + i))
+					return -EFAULT;
+				if (c == 'V')
+					expect_close = 42;
+			}
+		}
+		gef_wdt_service();
+	}
+
+	return len;
+}
+
+static int gef_wdt_ioctl(struct inode *inode, struct file *file,
+			     unsigned int cmd, unsigned long arg)
+{
+	int timeout;
+	int options;
+	void __user *argp = (void __user *)arg;
+	static struct watchdog_info info = {
+		.options =	WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
+				WDIOF_KEEPALIVEPING,
+		.firmware_version = 0,
+		.identity = "GE Fanuc watchdog",
+	};
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		if (copy_to_user(argp, &info, sizeof(info)))
+			return -EFAULT;
+		break;
+
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		if (put_user(wdt_status, (int __user *)argp))
+			return -EFAULT;
+		wdt_status &= ~WDIOF_KEEPALIVEPING;
+		break;
+
+	case WDIOC_GETTEMP:
+		return -EOPNOTSUPP;
+
+	case WDIOC_SETOPTIONS:
+		if (get_user(options, (int __user *)argp))
+			return -EFAULT;
+
+		if (options & WDIOS_DISABLECARD)
+			gef_wdt_handler_disable();
+
+		if (options & WDIOS_ENABLECARD)
+			gef_wdt_handler_enable();
+		break;
+
+	case WDIOC_KEEPALIVE:
+		gef_wdt_service();
+		wdt_status |= WDIOF_KEEPALIVEPING;
+		break;
+
+	case WDIOC_SETTIMEOUT:
+		if (get_user(timeout, (int __user *)argp))
+			return -EFAULT;
+		gef_wdt_set_timeout(timeout);
+		/* Fall through */
+
+	case WDIOC_GETTIMEOUT:
+		if (put_user(gef_wdt_timeout, (int __user *)argp))
+			return -EFAULT;
+		break;
+
+	default:
+		return -ENOTTY;
+	}
+
+	return 0;
+}
+
+static int gef_wdt_open(struct inode *inode, struct file *file)
+{
+	if (test_and_set_bit(GEF_WDOG_FLAG_OPENED, &wdt_flags))
+		return -EBUSY;
+
+	if (nowayout)
+		__module_get(THIS_MODULE);
+
+	gef_wdt_handler_enable();
+
+	return nonseekable_open(inode, file);
+}
+
+static int gef_wdt_release(struct inode *inode, struct file *file)
+{
+	if (expect_close == 42)
+		gef_wdt_handler_disable();
+	else {
+		printk(KERN_CRIT
+		       "gef_wdt: unexpected close, not stopping timer!\n");
+		gef_wdt_service();
+	}
+	expect_close = 0;
+
+	clear_bit(GEF_WDOG_FLAG_OPENED, &wdt_flags);
+
+	return 0;
+}
+
+static const struct file_operations gef_wdt_fops = {
+	.owner = THIS_MODULE,
+	.llseek = no_llseek,
+	.write = gef_wdt_write,
+	.ioctl = gef_wdt_ioctl,
+	.open = gef_wdt_open,
+	.release = gef_wdt_release,
+};
+
+static struct miscdevice gef_wdt_miscdev = {
+	.minor = WATCHDOG_MINOR,
+	.name = "watchdog",
+	.fops = &gef_wdt_fops,
+};
+
+
+static int __devinit gef_wdt_probe(struct of_device *dev,
+	const struct of_device_id *match)
+{
+	int timeout = 10;
+	u32 freq;
+
+	bus_clk = 133; /* in MHz */
+
+	freq = fsl_get_sys_freq();
+	if (freq > 0)
+		bus_clk = freq;
+
+	/* Map devices registers into memory */
+	gef_wdt_regs = of_iomap(dev->node, 0);
+	if (gef_wdt_regs == NULL)
+		return -ENOMEM;
+
+	gef_wdt_set_timeout(timeout);
+
+	gef_wdt_handler_disable();	/* in case timer was already running */
+
+	return misc_register(&gef_wdt_miscdev);
+}
+
+static int __devexit gef_wdt_remove(struct platform_device *dev)
+{
+	misc_deregister(&gef_wdt_miscdev);
+
+	gef_wdt_handler_disable();
+
+	iounmap(gef_wdt_regs);
+
+	return 0;
+}
+
+static const struct of_device_id gef_wdt_ids[] = {
+	{
+		.compatible = "gef,fpga-wdt",
+	},
+	{},
+};
+
+static struct of_platform_driver gef_wdt_driver = {
+	.owner		= THIS_MODULE,
+	.name		= "gef_wdt",
+	.match_table	= gef_wdt_ids,
+	.probe		= gef_wdt_probe,
+};
+
+static int __init gef_wdt_init(void)
+{
+	printk(KERN_INFO "GE Fanuc watchdog driver\n");
+	return of_register_platform_driver(&gef_wdt_driver);
+}
+
+static void __exit gef_wdt_exit(void)
+{
+	of_unregister_platform_driver(&gef_wdt_driver);
+}
+
+module_init(gef_wdt_init);
+module_exit(gef_wdt_exit);
+
+MODULE_AUTHOR("Martyn Welch <martyn.welch@gefanuc.com>");
+MODULE_DESCRIPTION("GE Fanuc watchdog driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_ALIAS("platform: gef_wdt");