libgloss/arc/arc-timer.c

   1 /*
   2  * arc-timer.c -- provide API for ARC timers.
   3  *
   4  * Copyright (c) 2024 Synopsys Inc.
   5  *
   6  * The authors hereby grant permission to use, copy, modify, distribute,
   7  * and license this software and its documentation for any purpose, provided
   8  * that existing copyright notices are retained in all copies and that this
   9  * notice is included verbatim in any distributions. No written agreement,
  10  * license, or royalty fee is required for any of the authorized uses.
  11  * Modifications to this software may be copyrighted by their authors
  12  * and need not follow the licensing terms described here, provided that
  13  * the new terms are clearly indicated on the first page of each file where
  14  * they apply.
  15  *
  16  */
  17
  18 #include "arc-specific.h"
  19
  20 #define ARC_TIM_BUILD           0x75
  21 #define ARC_TIM_BUILD_VER_MASK  0x00FF
  22 #define ARC_TIM_BUILD_TIM0_FL   0x0100
  23 #define ARC_TIM_BUILD_TIM1_FL   0x0200
  24
  25 #define ARC_TIM_COUNT0          0x21
  26 #define ARC_TIM_CONTROL0        0x22
  27 #define ARC_TIM_LIMIT0          0x23
  28
  29 #define ARC_TIM_COUNT1          0x100
  30 #define ARC_TIM_CONTROL1        0x101
  31 #define ARC_TIM_LIMIT1          0x102
  32
  33 #define ARC_TIM_CONTROL_NH_FL   0x0002
  34
  35 /* Timer used by '_default' functions.  */
  36 const unsigned int arc_timer_default = 0;
  37
  38 /* Check if given timer exists.  */
  39 static int
  40 _arc_timer_present (unsigned int tim)
  41 {
  42   unsigned int bcr = read_aux_reg (ARC_TIM_BUILD);
  43   unsigned int ver = bcr & ARC_TIM_BUILD_VER_MASK;
  44
  45   if (ver == 0)
  46     return 0;
  47   else if (ver == 1)
  48     return 1;
  49   else if (tim == 0)
  50     return ((bcr & ARC_TIM_BUILD_TIM0_FL) != 0);
  51   else if (tim == 1)
  52     return ((bcr & ARC_TIM_BUILD_TIM1_FL) != 0);
  53   else
  54     return 0;
  55 }
  56
  57 /* Get raw value of a given timer.  */
  58 static unsigned int
  59 _arc_timer_read (unsigned int tim)
  60 {
  61   if (_arc_timer_present (tim))
  62     {
  63       if (tim == 0)
  64         return read_aux_reg (ARC_TIM_COUNT0);
  65       else if (tim == 1)
  66         return read_aux_reg (ARC_TIM_COUNT1);
  67     }
  68
  69   return 0;
  70 }
  71
  72 /*
  73  * Set default values to a given timer.
  74  * Defaults: Not Halted bit is set, limit is 0xFFFFFFFF, count set to 0.
  75  */
  76 static void
  77 _arc_timer_reset (unsigned int tim)
  78 {
  79   unsigned int ctrl, tim_control, tim_count, tim_limit;
  80
  81   if (_arc_timer_present (tim))
  82     {
  83       if (tim == 0)
  84         {
  85           tim_control = ARC_TIM_CONTROL0;
  86           tim_count = ARC_TIM_COUNT0;
  87           tim_limit = ARC_TIM_LIMIT0;
  88         }
  89       else if (tim == 1)
  90         {
  91           tim_control = ARC_TIM_CONTROL1;
  92           tim_count = ARC_TIM_COUNT1;
  93           tim_limit = ARC_TIM_LIMIT1;
  94         }
  95       else
  96         {
  97           return;
  98         }
  99
 100       ctrl = read_aux_reg (tim_control);
 101       /* Disable timer interrupt when programming.  */
 102       write_aux_reg (0, tim_control);
 103       /* Default limit is 24-bit, increase it to 32-bit.  */
 104       write_aux_reg (0xFFFFFFFF, tim_limit);
 105       /* Set NH bit to count only when processor is running.  */
 106       write_aux_reg (ctrl | ARC_TIM_CONTROL_NH_FL, tim_control);
 107       write_aux_reg (0, tim_count);
 108     }
 109 }
 110
 111
 112 /* Check if arc_timer_default exists.  */
 113 int
 114 _arc_timer_default_present (void)
 115 {
 116   return _arc_timer_present (arc_timer_default);
 117 }
 118
 119 /* Read arc_timer_default value.  */
 120 unsigned int
 121 _arc_timer_default_read (void)
 122 {
 123   return _arc_timer_read (arc_timer_default);
 124 }
 125
 126 /* Reset arc_timer_default.  */
 127 void
 128 _arc_timer_default_reset (void)
 129 {
 130   _arc_timer_reset (arc_timer_default);
 131 }