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 Index: linux-2.6.25.4/arch/mips/Kconfig
  16 ===================================================================
  17 --- linux-2.6.25.4.orig/arch/mips/Kconfig
  18 +++ linux-2.6.25.4/arch/mips/Kconfig
  19 @@ -67,6 +67,8 @@ config BCM963XX
  20         select HW_HAS_PCI
  21         select DMA_NONCOHERENT
  22         select IRQ_CPU
  23 +       select CEVT_R4K
  24 +       select CSRC_R4K
  25         help
  26           This is a fmaily of boards based on the Broadcom MIPS32
  27
  28 Index: linux-2.6.25.4/arch/mips/bcm963xx/time.c
  29 ===================================================================
  30 --- linux-2.6.25.4.orig/arch/mips/bcm963xx/time.c
  31 +++ linux-2.6.25.4/arch/mips/bcm963xx/time.c
  32 @@ -1,6 +1,7 @@
  33  /*
  34  <:copyright-gpl
  35   Copyright 2004 Broadcom Corp. All Rights Reserved.
  36 + Copyright (C) 2008 Axel Gembe <ago@bastart.eu.org>
  37
  38   This program is free software; you can distribute it and/or modify it
  39   under the terms of the GNU General Public License (Version 2) as
  40 @@ -40,50 +41,43 @@
  41  #include <bcm_map_part.h>
  42  #include <bcm_intr.h>
  43
  44 -static unsigned long r4k_offset;       /* Amount to increment compare reg each time */
  45 -static unsigned long r4k_cur;          /* What counter should be at next timer irq */
  46 -
  47 -/*  *********************************************************************
  48 -    *  calculateCpuSpeed()
  49 -    *      Calculate the BCM6348 CPU speed by reading the PLL strap register
  50 -    *      and applying the following formula:
  51 -    *      cpu_clk = (.25 * 64MHz freq) * (N1 + 1) * (N2 + 2) / (M1_CPU + 1)
  52 -    *  Input parameters:
  53 -    *      none
  54 -    *  Return value:
  55 -    *      none
  56 -    ********************************************************************* */
  57 -
  58 +/*
  59 + * calculateCpuSpeed()
  60 + *
  61 + * Calculate the BCM6348 CPU speed by reading the PLL strap register and applying
  62 + * the following formula:
  63 + *
  64 + * cpu_clk = (.25 * 64MHz freq) * (N1 + 1) * (N2 + 2) / (M1_CPU + 1)
  65 + */
  66  static inline unsigned long __init calculateCpuSpeed(void)
  67  {
  68 -    u32 pllStrap = PERF->PllStrap;
  69 -    int n1 = (pllStrap & PLL_N1_MASK) >> PLL_N1_SHFT;
  70 -    int n2 = (pllStrap & PLL_N2_MASK) >> PLL_N2_SHFT;
  71 -    int m1cpu = (pllStrap & PLL_M1_CPU_MASK) >> PLL_M1_CPU_SHFT;
  72 +       u32 pllStrap;
  73 +       int n1, n2, m1cpu;
  74 +
  75 +       pllStrap = PERF->PllStrap;
  76 +       n1 = (pllStrap & PLL_N1_MASK) >> PLL_N1_SHFT;
  77 +       n2 = (pllStrap & PLL_N2_MASK) >> PLL_N2_SHFT;
  78 +       m1cpu = (pllStrap & PLL_M1_CPU_MASK) >> PLL_M1_CPU_SHFT;
  79
  80         return (16 * (n1 + 1) * (n2 + 2) / (m1cpu + 1)) * 1000000;
  81  }
  82
  83
  84 -static inline unsigned long __init cal_r4koff(void)
  85 -{
  86 -       mips_hpt_frequency = calculateCpuSpeed() / 2;
  87 -       return (mips_hpt_frequency / HZ);
  88 -}
  89 -
  90  void __init plat_time_init(void)
  91  {
  92 -       unsigned int est_freq, flags;
  93 -       local_irq_save(flags);
  94 +       unsigned long cpu_clock;
  95 +
  96 +       cpu_clock = calculateCpuSpeed();
  97 +
  98 +       printk("CPU frequency %lu.%02lu MHz\n", cpu_clock / 1000000,
  99 +               (cpu_clock % 1000000) * 100 / 1000000);
 100 +
 101 +       mips_hpt_frequency = cpu_clock / 2;
 102
 103 -       printk("calculating r4koff... ");
 104 -       r4k_offset = cal_r4koff();
 105 -       printk("%08lx(%d)\n", r4k_offset, (int)r4k_offset);
 106 -
 107 -       est_freq = 2 * r4k_offset * HZ;
 108 -       est_freq += 5000;   /* round */
 109 -       est_freq -= est_freq % 10000;
 110 -       printk("CPU frequency %d.%02d MHz\n", est_freq / 1000000,
 111 -                  (est_freq % 1000000) * 100 / 1000000);
 112 -       local_irq_restore(flags);
 113 +       /*
 114 +        * Use deterministic values for initial counter interrupt
 115 +        * so that calibrate delay avoids encountering a counter wrap.
 116 +        */
 117 +       write_c0_count(0);
 118 +       write_c0_compare(0xffff);
 119  }