arch/sh/include/asm/watchdog.h

   1 /*
   2  * include/asm-sh/watchdog.h
   3  *
   4  * Copyright (C) 2002, 2003 Paul Mundt
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the
   8  * Free Software Foundation; either version 2 of the License, or (at your
   9  * option) any later version.
  10  */
  11 #ifndef __ASM_SH_WATCHDOG_H
  12 #define __ASM_SH_WATCHDOG_H
  13 #ifdef __KERNEL__
  14
  15 #include <linux/types.h>
  16 #include <cpu/watchdog.h>
  17 #include <asm/io.h>
  18
  19 /*
  20  * See cpu-sh2/watchdog.h for explanation of this stupidity..
  21  */
  22 #ifndef WTCNT_R
  23 #  define WTCNT_R       WTCNT
  24 #endif
  25
  26 #ifndef WTCSR_R
  27 #  define WTCSR_R       WTCSR
  28 #endif
  29
  30 #define WTCNT_HIGH      0x5a
  31 #define WTCSR_HIGH      0xa5
  32
  33 #define WTCSR_CKS2      0x04
  34 #define WTCSR_CKS1      0x02
  35 #define WTCSR_CKS0      0x01
  36
  37 /*
  38  * CKS0-2 supports a number of clock division ratios. At the time the watchdog
  39  * is enabled, it defaults to a 41 usec overflow period .. we overload this to
  40  * something a little more reasonable, and really can't deal with anything
  41  * lower than WTCSR_CKS_1024, else we drop back into the usec range.
  42  *
  43  * Clock Division Ratio         Overflow Period
  44  * --------------------------------------------
  45  *     1/32 (initial value)       41 usecs
  46  *     1/64                       82 usecs
  47  *     1/128                     164 usecs
  48  *     1/256                     328 usecs
  49  *     1/512                     656 usecs
  50  *     1/1024                   1.31 msecs
  51  *     1/2048                   2.62 msecs
  52  *     1/4096                   5.25 msecs
  53  */
  54 #define WTCSR_CKS_32    0x00
  55 #define WTCSR_CKS_64    0x01
  56 #define WTCSR_CKS_128   0x02
  57 #define WTCSR_CKS_256   0x03
  58 #define WTCSR_CKS_512   0x04
  59 #define WTCSR_CKS_1024  0x05
  60 #define WTCSR_CKS_2048  0x06
  61 #define WTCSR_CKS_4096  0x07
  62
  63 /**
  64  *      sh_wdt_read_cnt - Read from Counter
  65  *      Reads back the WTCNT value.
  66  */
  67 static inline __u8 sh_wdt_read_cnt(void)
  68 {
  69         return ctrl_inb(WTCNT_R);
  70 }
  71
  72 /**
  73  *      sh_wdt_write_cnt - Write to Counter
  74  *      @val: Value to write
  75  *
  76  *      Writes the given value @val to the lower byte of the timer counter.
  77  *      The upper byte is set manually on each write.
  78  */
  79 static inline void sh_wdt_write_cnt(__u8 val)
  80 {
  81         ctrl_outw((WTCNT_HIGH << 8) | (__u16)val, WTCNT);
  82 }
  83
  84 /**
  85  *      sh_wdt_read_csr - Read from Control/Status Register
  86  *
  87  *      Reads back the WTCSR value.
  88  */
  89 static inline __u8 sh_wdt_read_csr(void)
  90 {
  91         return ctrl_inb(WTCSR_R);
  92 }
  93
  94 /**
  95  *      sh_wdt_write_csr - Write to Control/Status Register
  96  *      @val: Value to write
  97  *
  98  *      Writes the given value @val to the lower byte of the control/status
  99  *      register. The upper byte is set manually on each write.
 100  */
 101 static inline void sh_wdt_write_csr(__u8 val)
 102 {
 103         ctrl_outw((WTCSR_HIGH << 8) | (__u16)val, WTCSR);
 104 }
 105
 106 #endif /* __KERNEL__ */
 107 #endif /* __ASM_SH_WATCHDOG_H */