Add C5471 watchdog driver

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@66 42af7a65-404d-4744-a932-0658087f49c3

ChangeLog

@@ -36,4 +36,5 @@
 
 	* Add dirent.h, opendir(), readdir(), closedir(), etc.
 	* Added 'ls' command to nsh
+	* Added C5471 watchdog driver
 

arch/c5471/include/watchdog.h

+/************************************************************
+ * watchdog.h
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name Gregory Nutt nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ************************************************************/
+
+#ifndef __ARCH_WATCHDOG_H
+#define __ARCH_WATCHDOG_H
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+/************************************************************
+ * Definitions
+ ************************************************************/
+
+/* IOCTL commands supported by the C5471 watchdog driver */
+
+#define WDIOC_KEEPALIVE 0x5701  /* Restart the watchdog timer */
+
+/************************************************************
+ * Private Data
+ ************************************************************/
+
+/************************************************************
+ * Private Functions
+ ************************************************************/
+
+/************************************************************
+ * Public Functions
+ ************************************************************/
+
+#endif /* __ARCH_WATCHDOG_H */

arch/c5471/src/Makefile

@@ -51,7 +51,7 @@ CSRCS		= up_initialize.c up_initialstate.c up_idle.c up_doirq.c \
 		  up_exit.c up_assert.c up_blocktask.c up_unblocktask.c \
 		  up_releasepending.c up_reprioritizertr.c up_copystate.c \
 		  up_schedulesigaction.c up_sigdeliver.c up_serial.c \
-		  up_delay.c up_allocateheap.c up_leds.c
+		  up_delay.c up_allocateheap.c up_leds.c up_watchdog.c
 COBJS		= $(CSRCS:.c=.o)
 
 SRCS		= $(ASRCS) $(CSRCS)

arch/c5471/src/up_internal.h

@@ -142,6 +142,10 @@ extern void up_vectorfiq(void);
 extern void up_earlyserialinit(void);
 extern void up_serialinit(void);
 
+/* Defined in up_watchdog.c */
+
+extern void up_wdtinit(void);
+
 /* Defined in up_timerisr.c */
 
 extern void up_timerinit(void);

arch/c5471/src/up_watchdog.c

+/**************************************************************************
+ * up_watchdog.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name Gregory Nutt nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ **************************************************************************/
+
+/**************************************************************************
+ * Included Files
+ **************************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+#include <stdio.h>
+#include <debug.h>
+#include <errno.h>
+#include <nuttx/fs.h>
+#include <nuttx/irq.h>
+#include <arch/watchdog.h>
+#include "c5471.h"
+
+/**************************************************************************
+ * Definitions
+ **************************************************************************/
+
+#undef CONFIG_SOFTWARE_TEST
+#undef CONFIG_SOFTWARE_REBOOT
+#undef CONFIG_WATCHDOG_STRICT
+
+#define MAX_WDT_USEC           353200
+#define MAX_PRESCALER          256
+#define C5471_TIMER_STOP       0
+
+#define C5471_TIMER_PRESCALER  0x07          /* Bits 0-2: Prescale value */
+#define C5471_TIMER_STARTBIT   (1 << 3)      /* Bit 3: Start timer bit */
+#define C5471_TIMER_AUTORELOAD (1 << 4)      /* Bit 4: Auto-reload timer */
+#define C5471_TIMER_LOADTIM    (0xffff << 5) /* Bits 20-5: Load timer value */
+#define C5471_TIMER_MODE       (1 << 21)     /* Bit 21: Timer mode */
+#define C5471_DISABLE_VALUE1   (0xf5 << 22)  /* Bits 29-22: WD disable */
+#define C5471_DISABLE_VALUE2   (0xa0 << 22)
+
+#define CLOCK_KHZ              47500
+#define CLOCK_MHZx2            95
+
+/* Macros to manage access to to watchdog timer macros */
+
+#define c5471_wdt_cntl  (*(volatile uint32*)C5471_TIMER0_CTRL)
+#define c5471_wdt_count (*(volatile uint32*)C5471_TIMER0_CNT)
+
+/**************************************************************************
+ * Private Types
+ **************************************************************************/
+
+/**************************************************************************
+ * Private Function Prototypes
+ **************************************************************************/
+
+/* Local implementation of timer interface */
+
+static inline unsigned int wdt_prescaletoptv(unsigned int prescale);
+
+static int     wdt_setusec(uint32 usec);
+static int     wdt_interrupt(int irq, void *context);
+
+static int     wdt_open(struct file *filep);
+static int     wdt_close(struct file *filep);
+static ssize_t wdt_read(struct file *filep, char *buffer, size_t buflen);
+static ssize_t wdt_write(struct file *filep, const char *buffer, size_t buflen);
+static int     wdt_ioctl(struct file *filep, int cmd, uint32 arg);
+
+/**************************************************************************
+ * Private Data
+ **************************************************************************/
+
+static boolean g_wdtopen;
+
+struct file_operations g_wdtops =
+{
+  .open  = wdt_open,
+  .close = wdt_close,
+  .read  = wdt_read,
+  .write = wdt_write,
+  .ioctl = wdt_ioctl,
+};
+
+/**************************************************************************
+ * Private Functions
+ **************************************************************************/
+
+/**************************************************************************
+ * Name: wdt_prescaletoptv
+ **************************************************************************/
+
+static inline unsigned int wdt_prescaletoptv(unsigned int prescale)
+{
+  unsigned int ptv = 0;
+
+  if (prescale > 255)
+    {
+      ptv = 7;
+    }
+  else
+    {
+      unsigned int value = prescale >> 1;
+
+      /* 0: 0-2
+       * 1: 3-4
+       * 2: 5-8
+       * 3: 9-16
+       * 4: 17-32
+       * 5: 33-64
+       * 6: 65-128
+       * 7: 129-
+       */
+
+      while (value > 1)
+        {
+          value >>= 1;
+          ptv++;
+        }
+    }
+
+  dbg("prescale=%d -> ptv=%d\n", prescale, ptv);
+  return ptv;
+}
+
+/**************************************************************************
+ * Name: wdt_setusec
+ **************************************************************************/
+
+static int wdt_setusec(uint32 usec)
+{
+  /* prescaler: clock / prescaler = #clock ticks per counter in ptv
+   * divisor:   #counts until the interrupt comes.
+   */
+
+  uint32 prescaler = MAX_PRESCALER;
+  uint32 divisor   = 1;
+  uint32 mode;
+
+  dbg("usec=%d\n", usec);
+
+  /* Calculate a value of prescaler and divisor that will be able
+   * to count to the usec.  It may not be exact or the best
+   * possible set, but it's a quick and simple algorithm.
+   *
+   *    divisor max = 0x10000
+   *    prescaler max = MAX_PRESCALER
+   */
+
+  do
+    {
+      divisor = (CLOCK_MHZx2 * usec) / (prescaler * 2);
+      dbg("divisor=0x%x prescaler=0x%x\n", divisor, prescaler);
+
+      if (divisor >= 0x10000)
+        {
+          if (prescaler == MAX_PRESCALER)
+            { 
+              /* This is the max possible ~2.5 seconds. */
+
+              dbg("prescaler=0x%x too big!\n", prescaler);
+              return ERROR;
+            }
+
+          prescaler <<= 1;
+          if (prescaler > MAX_PRESCALER)
+            {
+              prescaler = MAX_PRESCALER;
+            }
+        }
+    }
+  while (divisor >= 0x10000);
+
+  dbg("prescaler=0x%x divisor=0x%x\n", prescaler, divisor);
+
+  mode  = wdt_prescaletoptv(prescaler);
+  mode &= ~C5471_TIMER_AUTORELOAD; /* One shot mode. */
+  mode |= divisor << 5;
+  dbg("mode=0x%x\n", mode);
+
+  c5471_wdt_cntl = mode;
+
+  /* Now start the watchdog */
+
+  c5471_wdt_cntl |= C5471_TIMER_STARTBIT;
+  dbg("cntl_timer=0x%x\n", c5471_wdt_cntl);
+
+  return 0;
+}
+
+/**************************************************************************
+ * Private Functions
+ **************************************************************************/
+
+/**************************************************************************
+ * Name: wdt_interrupt
+ **************************************************************************/
+
+static int wdt_interrupt(int irq, void *context)
+{
+  dbg("expired\n");
+
+#if defined(CONFIG_SOFTWARE_REBOOT)
+#  if defined(CONFIG_SOFTWARE_TEST)
+  dbg("  Test only\n");
+#  else
+  dbg("  Re-booting\n");
+#    warning "Add logic to reset CPU here"
+#  endif
+#else
+  dbg("  No reboot\n");
+#endif
+  return OK;
+}
+
+/**************************************************************************
+ * Name: wdt_read
+ **************************************************************************/
+
+static ssize_t wdt_read(struct file *filep, char *buffer, size_t buflen)
+{
+  /* We are going to return "NNNNNNNN NNNNNNNN."  The followig logic will
+   * not work if the user provides a buffer smaller than 18 bytes.
+   */
+
+  dbg("buflen=%d\n", buflen);
+  if (buflen >= 18)
+    {
+      sprintf(buffer, "#08x %08x\n", c5471_wdt_cntl, c5471_wdt_count);
+      return 18;
+    }
+  return 0;
+}
+
+/**************************************************************************
+ * Name: wdt_write
+ **************************************************************************/
+
+static ssize_t wdt_write(struct file *filep, const char *buffer, size_t buflen)
+{
+  dbg("buflen=%d\n", buflen);
+  if (buflen)
+    {
+      /* Reset the timer to the maximum delay */
+
+      wdt_setusec(MAX_WDT_USEC);
+      return 1;
+    }
+
+  return 0;
+}
+
+/**************************************************************************
+ * Name: wdt_ioctl
+ **************************************************************************/
+
+static int wdt_ioctl(struct file *filep, int cmd, uint32 arg)
+{
+  dbg("ioctl Call: cmd=0x%x arg=0x%x", cmd, arg);
+
+  /* Process the the IOCTL command (see arch/watchdog.h) */
+
+  switch(cmd)
+    {
+    case WDIOC_KEEPALIVE:
+      wdt_setusec(MAX_WDT_USEC);
+      break;
+
+    default:
+      *get_errno_ptr() = ENOTTY;
+      return ERROR;
+    }
+
+  return OK;
+}
+
+/**************************************************************************
+ * Name: wdt_open
+ **************************************************************************/
+
+static int wdt_open(struct file *filep)
+{
+  dbg("");
+
+  if (g_wdtopen)
+    {
+      *get_errno_ptr() = EBUSY;
+    }
+
+  /* This will automatically load the timer with its max
+   * count and start it running.
+   */
+
+  c5471_wdt_cntl = C5471_DISABLE_VALUE1;
+  c5471_wdt_cntl = C5471_DISABLE_VALUE2;
+
+  g_wdtopen = TRUE;
+  return OK;
+}
+
+/**************************************************************************
+ * Name: wdt_close
+ **************************************************************************/
+
+static int wdt_close(struct file *filep)
+{
+  dbg("");
+
+  /* The task controlling the watchdog has terminated.  Take the timer
+   *  the
+   * watchdog in interrupt mode -- we are going to reset unless the
+   * reopened again soon.
+   */
+
+#ifndef CONFIG_WATCHDOG_STRICT
+  c5471_wdt_cntl = C5471_TIMER_MODE;
+#endif
+
+  g_wdtopen = FALSE;
+  return 0;
+}
+
+/**************************************************************************
+ * Public Functions
+ **************************************************************************/
+
+/**************************************************************************
+ * Name: up_wdtinit
+ **************************************************************************/
+
+int up_wdtinit(void)
+{
+  int ret;
+
+  dbg("C547x Watchdog Driver\n");
+
+  /* Register as /dev/wdt */
+
+  ret = register_inode("/dev/wdt", &g_wdtops, 0666, NULL);
+  if (ret)
+    {
+      return ERROR;
+    }
+
+  /* Register for an interrupt level callback through wdt_interrupt */
+
+  dbg("Attach to IRQ=%d\n", C5471_IRQ_WATCHDOG);
+
+  /* Make sure that the timer is stopped */
+
+  c5471_wdt_cntl = C5471_TIMER_STOP;
+
+  /* Request the interrupt. */
+
+  ret = irq_attach(C5471_IRQ_WATCHDOG, wdt_interrupt);
+  if (ret)
+    {
+      unregister_inode("/dev/wdt");
+      return ERROR;
+    }
+
+  return OK;
+}