mpc8xx watchdog timer (2.4.22-bk26)

Hi,

the attached patch adds support for the internal watchdog of the mpc8xx
series of CPUs including the watchdog user space interface. It has been
tested on the D-Box2 board which requires this patch because the
watchdog timer is enabled by its boot loader. It should work on other
8xx boards as well.

Any comments?

Regards,
Andreas
===== arch/ppc/kernel/Makefile 1.34 vs edited =====
--- 1.34/arch/ppc/kernel/Makefile	Fri Aug 29 06:31:27 2003
+++ edited/arch/ppc/kernel/Makefile	Tue Sep 30 05:01:44 2003
@@ -64,6 +64,9 @@
 obj-$(CONFIG_PPC4xx_DMA)	+= ppc4xx_dma.o
 obj-$(CONFIG_PPC4xx_EDMA)	+= ppc4xx_sgdma.o
 obj-$(CONFIG_8xx)		+= m8xx_setup.o ppc8xx_pic.o
+ifdef CONFIG_8xx_WDT
+obj-y				+= m8xx_wdt.o
+endif
 ifeq ($(CONFIG_8xx),y)
 obj-$(CONFIG_PCI)		+= qspan_pci.o
 ifndef CONFIG_MATH_EMULATION
===== arch/ppc/kernel/m8xx_setup.c 1.22 vs edited =====
--- 1.22/arch/ppc/kernel/m8xx_setup.c	Thu Jul  3 18:56:34 2003
+++ edited/arch/ppc/kernel/m8xx_setup.c	Tue Sep 30 05:01:46 2003
@@ -58,6 +58,7 @@
 
 extern unsigned long find_available_memory(void);
 extern void m8xx_cpm_reset(uint);
+extern void m8xx_wdt_handler_install(bd_t *bp);
 
 void __init
 m8xx_setup_arch(void)
@@ -184,6 +185,13 @@
 	if (request_irq(DEC_INTERRUPT, timebase_interrupt, 0, "tbint",
 				NULL) != 0)
 		panic("Could not allocate timer IRQ!");
+
+#ifdef CONFIG_8xx_WDT
+	/* Install watchdog timer handler early because it might be
+	 * already enabled by the bootloader
+	 */
+	m8xx_wdt_handler_install(binfo);
+#endif
 }
 
 /* The RTC on the MPC8xx is an internal register.
===== arch/ppc/kernel/ppc_ksyms.c 1.36 vs edited =====
--- 1.36/arch/ppc/kernel/ppc_ksyms.c	Sat Sep 27 06:10:40 2003
+++ edited/arch/ppc/kernel/ppc_ksyms.c	Tue Sep 30 05:33:27 2003
@@ -357,6 +357,12 @@
 EXPORT_SYMBOL(cpm_free_handler);
 EXPORT_SYMBOL(m8xx_cpm_hostalloc);
 EXPORT_SYMBOL(m8xx_cpm_dpalloc);
+#ifdef CONFIG_8xx_WDT
+extern int m8xx_wdt_get_timeout(void);
+extern void m8xx_wdt_reset(void);
+EXPORT_SYMBOL(m8xx_wdt_get_timeout);
+EXPORT_SYMBOL(m8xx_wdt_reset);
+#endif /* CONFIG_8xx_WDT */
 #endif /* CONFIG_8xx */
 
 /* Those should really be inline */
===== drivers/char/Config.in 1.58 vs edited =====
--- 1.58/drivers/char/Config.in	Thu Sep 25 05:54:18 2003
+++ edited/drivers/char/Config.in	Tue Sep 30 05:01:48 2003
@@ -254,6 +254,7 @@
    fi
    tristate '  ZF MachZ Watchdog' CONFIG_MACHZ_WDT
    dep_tristate '  AMD 766/768 TCO Timer/Watchdog' CONFIG_AMD7XX_TCO $CONFIG_EXPERIMENTAL
+   dep_tristate '  MPC8xx Watchdog Timer' CONFIG_8xx_WDT $CONFIG_8xx
 fi
 endmenu
 
===== drivers/char/Makefile 1.37 vs edited =====
--- 1.37/drivers/char/Makefile	Wed Aug 27 22:18:26 2003
+++ edited/drivers/char/Makefile	Tue Sep 30 05:01:49 2003
@@ -305,6 +305,7 @@
 obj-$(CONFIG_WAFER_WDT) += wafer5823wdt.o
 obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
 obj-$(CONFIG_AMD7XX_TCO) += amd7xx_tco.o
+obj-$(CONFIG_8xx_WDT) += mpc8xx_wdt.o
 
 subdir-$(CONFIG_MWAVE) += mwave
 ifeq ($(CONFIG_MWAVE),y)
===== arch/ppc/kernel/m8xx_wdt.c 1.0 vs 1.1 =====
--- /dev/null	Thu Jan  1 01:00:00 1970
+++ 1.1/arch/ppc/kernel/m8xx_wdt.c	Tue Sep 30 05:34:45 2003
@@ -0,0 +1,103 @@
+/*
+ * m8xx_wdt.c - MPC8xx watchdog driver
+ *
+ * Copyright (C) 2002 Florian Schirmer <jolt@tuxbox.org>
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <asm/8xx_immap.h>
+
+static int wdt_timeout;
+
+void m8xx_wdt_reset(void)
+{
+	volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
+
+	imap->im_siu_conf.sc_swsr = 0x556c;	/* write magic1 */
+	imap->im_siu_conf.sc_swsr = 0xaa39;	/* write magic2 */
+}
+
+static void m8xx_wdt_interrupt(int irq, void *dev, struct pt_regs *regs)
+{
+	volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
+
+	m8xx_wdt_reset();
+
+	imap->im_sit.sit_piscr |= PISCR_PS;	/* clear irq */
+}
+
+void __init m8xx_wdt_handler_install(bd_t *binfo)
+{
+	volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
+	u32 pitc;
+	u32 sypcr;
+	u32 pitrtclk;
+
+	sypcr = imap->im_siu_conf.sc_sypcr;
+
+	if (!(sypcr & 0x04)) {
+		printk(KERN_NOTICE "m8xx_wdt: wdt disabled (SYPCR: 0x%08X)\n", sypcr);
+		return;
+	}
+
+	m8xx_wdt_reset();
+
+	printk(KERN_NOTICE "m8xx_wdt: active wdt found (SWTC: 0x%04X, SWP: 0x%01X)\n",
+			(sypcr >> 16), sypcr & 0x01);
+
+	wdt_timeout = (sypcr >> 16) & 0xFFFF;
+
+	if (!wdt_timeout)
+		wdt_timeout = 0xFFFF;
+
+	if (sypcr & 0x01)
+		wdt_timeout *= 2048;
+
+	/*
+	 * Fire trigger if half of the wdt ticked down 
+	 */
+
+	if (imap->im_sit.sit_rtcsc & RTCSC_38K)
+		pitrtclk = 9600;
+	else
+		pitrtclk = 8192;
+
+	if ((wdt_timeout) > (UINT_MAX / pitrtclk))
+		pitc = wdt_timeout / binfo->bi_intfreq * pitrtclk / 2;
+	else
+		pitc = pitrtclk * wdt_timeout / binfo->bi_intfreq / 2;
+
+	imap->im_sit.sit_pitc = pitc << 16;
+	imap->im_sit.sit_piscr = (mk_int_int_mask(PIT_INTERRUPT) << 8) | PISCR_PIE | PISCR_PTE;
+
+	if (request_irq(PIT_INTERRUPT, m8xx_wdt_interrupt, 0, "watchdog", NULL))
+		panic("m8xx_wdt: could not allocate watchdog irq!");
+
+	printk(KERN_NOTICE "m8xx_wdt: keep-alive trigger installed (PITC: 0x%04X)\n", pitc);
+
+	wdt_timeout /= binfo->bi_intfreq;
+}
+
+int m8xx_wdt_get_timeout(void)
+{
+	return wdt_timeout;
+}
+
===== drivers/char/mpc8xx_wdt.c 1.0 vs 1.1 =====
--- /dev/null	Thu Jan  1 01:00:00 1970
+++ 1.1/drivers/char/mpc8xx_wdt.c	Tue Sep 30 05:34:51 2003
@@ -0,0 +1,183 @@
+/*
+ * mpc8xx_wdt.c - MPC8xx watchdog userspace interface
+ *
+ * Copyright (C) 2002 Florian Schirmer <jolt@tuxbox.org>
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/watchdog.h>
+#include <asm/8xx_immap.h>
+#include <asm/uaccess.h>
+
+extern int m8xx_wdt_get_timeout(void);
+extern void m8xx_wdt_reset(void);
+
+static struct semaphore wdt_sem;
+static int wdt_status;
+
+static struct watchdog_info ident = {
+	.identity = "MPC8xx watchdog",
+	.options = WDIOF_KEEPALIVEPING,
+};
+
+static void mpc8xx_wdt_handler_disable(void)
+{
+	volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
+
+	imap->im_sit.sit_piscr &= ~(PISCR_PIE | PISCR_PTE);
+
+	printk(KERN_NOTICE "mpc8xx_wdt: keep-alive handler deactivated\n");
+}
+
+static void mpc8xx_wdt_handler_enable(void)
+{
+	volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
+
+	imap->im_sit.sit_piscr |= PISCR_PIE | PISCR_PTE;
+
+	printk(KERN_NOTICE "mpc8xx_wdt: keep-alive handler activated\n");
+}
+
+static int mpc8xx_wdt_open(struct inode *inode, struct file *file)
+{
+	switch (MINOR(inode->i_rdev)) {
+	case WATCHDOG_MINOR:
+		if (down_trylock(&wdt_sem))
+			return -EBUSY;
+
+		m8xx_wdt_reset();
+		mpc8xx_wdt_handler_disable();
+		break;
+
+	default:
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int mpc8xx_wdt_release(struct inode *inode, struct file *file)
+{
+	m8xx_wdt_reset();
+
+#if !defined(CONFIG_WATCHDOG_NOWAYOUT)
+	mpc8xx_wdt_handler_enable();
+#endif
+
+	up(&wdt_sem);
+
+	return 0;
+}
+
+static ssize_t mpc8xx_wdt_write(struct file *file, const char *data,
+				size_t len, loff_t * ppos)
+{
+	/* Can't seek (pwrite) on this device */
+	if (ppos != &file->f_pos)
+		return -ESPIPE;
+
+	if (!len)
+		return 0;
+
+	m8xx_wdt_reset();
+
+	return 1;
+}
+
+static int mpc8xx_wdt_ioctl(struct inode *inode, struct file *file,
+			    unsigned int cmd, unsigned long arg)
+{
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		if (copy_to_user((void *)arg, &ident, sizeof(ident)))
+			return -EFAULT;
+		break;
+
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		if (put_user(wdt_status, (int *)arg))
+			return -EFAULT;
+		wdt_status &= ~WDIOF_KEEPALIVEPING;
+		break;
+
+	case WDIOC_KEEPALIVE:
+		m8xx_wdt_reset();
+		wdt_status |= WDIOF_KEEPALIVEPING;
+		break;
+
+	case WDIOC_GETTIMEOUT:
+	{
+		int timeout = m8xx_wdt_get_timeout();
+		if (put_user(timeout, (int *)arg))
+			return -EFAULT;
+		break;
+	}
+
+	default:
+		return -ENOTTY;
+	}
+
+	return 0;
+}
+
+static struct file_operations mpc8xx_wdt_fops = {
+	.owner = THIS_MODULE,
+	.write = mpc8xx_wdt_write,
+	.ioctl = mpc8xx_wdt_ioctl,
+	.open = mpc8xx_wdt_open,
+	.release = mpc8xx_wdt_release,
+};
+
+static struct miscdevice mpc8xx_wdt_miscdev = {
+	.minor = WATCHDOG_MINOR,
+	.name = "watchdog",
+	.fops = &mpc8xx_wdt_fops,
+};
+
+static int __init mpc8xx_wdt_init(void)
+{
+	int ret;
+
+	sema_init(&wdt_sem, 1);
+
+	if ((ret = misc_register(&mpc8xx_wdt_miscdev))) {
+		printk(KERN_WARNING "mpc8xx_wdt: cound not register userspace interface\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static void __exit mpc8xx_wdt_exit(void)
+{
+	misc_deregister(&mpc8xx_wdt_miscdev);
+
+	m8xx_wdt_reset();
+	mpc8xx_wdt_handler_enable();
+}
+
+module_init(mpc8xx_wdt_init);
+module_exit(mpc8xx_wdt_exit);
+
+MODULE_AUTHOR("Florian Schirmer <jolt@tuxbox.org>");
+MODULE_DESCRIPTION("MPC8xx watchdog driver");
+MODULE_LICENSE("GPL");