target/linux/brcm63xx/patches-2.6.25/100-bcm963xx_add_new_timer_code.patch

   1 From 7d6656dc127b54e53e507e8f264bb7e14e620cad Mon Sep 17 00:00:00 2001
   2 From: Axel Gembe <ago@bastart.eu.org>
   3 Date: Sat, 17 May 2008 15:02:39 +0200
   4 Subject: [PATCH] bcm963xx: add new timer code
   5
   6 This basically selects the new generic MIPS timer code for BCM963xx and
   7 simplifies the timer setup code.
   8
   9 Signed-off-by: Axel Gembe <ago@bastart.eu.org>
  10 ---
  11  arch/mips/Kconfig         |    2 +
  12  arch/mips/bcm963xx/time.c |   64 ++++++++++++++++++++------------------------
  13  2 files changed, 31 insertions(+), 35 deletions(-)
  14
  15 --- a/arch/mips/Kconfig
  16 +++ b/arch/mips/Kconfig
  17 @@ -67,6 +67,8 @@
  18         select HW_HAS_PCI
  19         select DMA_NONCOHERENT
  20         select IRQ_CPU
  21 +       select CEVT_R4K
  22 +       select CSRC_R4K
  23         help
  24           This is a fmaily of boards based on the Broadcom MIPS32
  25
  26 --- a/arch/mips/bcm963xx/time.c
  27 +++ b/arch/mips/bcm963xx/time.c
  28 @@ -1,6 +1,7 @@
  29  /*
  30  <:copyright-gpl
  31   Copyright 2004 Broadcom Corp. All Rights Reserved.
  32 + Copyright (C) 2008 Axel Gembe <ago@bastart.eu.org>
  33
  34   This program is free software; you can distribute it and/or modify it
  35   under the terms of the GNU General Public License (Version 2) as
  36 @@ -40,50 +41,43 @@
  37  #include <bcm_map_part.h>
  38  #include <bcm_intr.h>
  39
  40 -static unsigned long r4k_offset;       /* Amount to increment compare reg each time */
  41 -static unsigned long r4k_cur;          /* What counter should be at next timer irq */
  42 -
  43 -/*  *********************************************************************
  44 -    *  calculateCpuSpeed()
  45 -    *      Calculate the BCM6348 CPU speed by reading the PLL strap register
  46 -    *      and applying the following formula:
  47 -    *      cpu_clk = (.25 * 64MHz freq) * (N1 + 1) * (N2 + 2) / (M1_CPU + 1)
  48 -    *  Input parameters:
  49 -    *      none
  50 -    *  Return value:
  51 -    *      none
  52 -    ********************************************************************* */
  53 -
  54 +/*
  55 + * calculateCpuSpeed()
  56 + *
  57 + * Calculate the BCM6348 CPU speed by reading the PLL strap register and applying
  58 + * the following formula:
  59 + *
  60 + * cpu_clk = (.25 * 64MHz freq) * (N1 + 1) * (N2 + 2) / (M1_CPU + 1)
  61 + */
  62  static inline unsigned long __init calculateCpuSpeed(void)
  63  {
  64 -    u32 pllStrap = PERF->PllStrap;
  65 -    int n1 = (pllStrap & PLL_N1_MASK) >> PLL_N1_SHFT;
  66 -    int n2 = (pllStrap & PLL_N2_MASK) >> PLL_N2_SHFT;
  67 -    int m1cpu = (pllStrap & PLL_M1_CPU_MASK) >> PLL_M1_CPU_SHFT;
  68 +       u32 pllStrap;
  69 +       int n1, n2, m1cpu;
  70 +
  71 +       pllStrap = PERF->PllStrap;
  72 +       n1 = (pllStrap & PLL_N1_MASK) >> PLL_N1_SHFT;
  73 +       n2 = (pllStrap & PLL_N2_MASK) >> PLL_N2_SHFT;
  74 +       m1cpu = (pllStrap & PLL_M1_CPU_MASK) >> PLL_M1_CPU_SHFT;
  75
  76         return (16 * (n1 + 1) * (n2 + 2) / (m1cpu + 1)) * 1000000;
  77  }
  78
  79
  80 -static inline unsigned long __init cal_r4koff(void)
  81 -{
  82 -       mips_hpt_frequency = calculateCpuSpeed() / 2;
  83 -       return (mips_hpt_frequency / HZ);
  84 -}
  85 -
  86  void __init plat_time_init(void)
  87  {
  88 -       unsigned int est_freq, flags;
  89 -       local_irq_save(flags);
  90 +       unsigned long cpu_clock;
  91 +
  92 +       cpu_clock = calculateCpuSpeed();
  93 +
  94 +       printk("CPU frequency %lu.%02lu MHz\n", cpu_clock / 1000000,
  95 +               (cpu_clock % 1000000) * 100 / 1000000);
  96 +
  97 +       mips_hpt_frequency = cpu_clock / 2;
  98
  99 -       printk("calculating r4koff... ");
 100 -       r4k_offset = cal_r4koff();
 101 -       printk("%08lx(%d)\n", r4k_offset, (int)r4k_offset);
 102 -
 103 -       est_freq = 2 * r4k_offset * HZ;
 104 -       est_freq += 5000;   /* round */
 105 -       est_freq -= est_freq % 10000;
 106 -       printk("CPU frequency %d.%02d MHz\n", est_freq / 1000000,
 107 -                  (est_freq % 1000000) * 100 / 1000000);
 108 -       local_irq_restore(flags);
 109 +       /*
 110 +        * Use deterministic values for initial counter interrupt
 111 +        * so that calibrate delay avoids encountering a counter wrap.
 112 +        */
 113 +       write_c0_count(0);
 114 +       write_c0_compare(0xffff);
 115  }