linux/drivers/cpufreq/ppc_cbe_cpufreq_pervasive.c
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   1/*
   2 * pervasive backend for the cbe_cpufreq driver
   3 *
   4 * This driver makes use of the pervasive unit to
   5 * engage the desired frequency.
   6 *
   7 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
   8 *
   9 * Author: Christian Krafft <krafft@de.ibm.com>
  10 *
  11 * This program is free software; you can redistribute it and/or modify
  12 * it under the terms of the GNU General Public License as published by
  13 * the Free Software Foundation; either version 2, or (at your option)
  14 * any later version.
  15 *
  16 * This program is distributed in the hope that it will be useful,
  17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 * GNU General Public License for more details.
  20 *
  21 * You should have received a copy of the GNU General Public License
  22 * along with this program; if not, write to the Free Software
  23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  24 */
  25
  26#include <linux/io.h>
  27#include <linux/kernel.h>
  28#include <linux/time.h>
  29#include <asm/machdep.h>
  30#include <asm/hw_irq.h>
  31#include <asm/cell-regs.h>
  32
  33#include "ppc_cbe_cpufreq.h"
  34
  35/* to write to MIC register */
  36static u64 MIC_Slow_Fast_Timer_table[] = {
  37        [0 ... 7] = 0x007fc00000000000ull,
  38};
  39
  40/* more values for the MIC */
  41static u64 MIC_Slow_Next_Timer_table[] = {
  42        0x0000240000000000ull,
  43        0x0000268000000000ull,
  44        0x000029C000000000ull,
  45        0x00002D0000000000ull,
  46        0x0000300000000000ull,
  47        0x0000334000000000ull,
  48        0x000039C000000000ull,
  49        0x00003FC000000000ull,
  50};
  51
  52
  53int cbe_cpufreq_set_pmode(int cpu, unsigned int pmode)
  54{
  55        struct cbe_pmd_regs __iomem *pmd_regs;
  56        struct cbe_mic_tm_regs __iomem *mic_tm_regs;
  57        unsigned long flags;
  58        u64 value;
  59#ifdef DEBUG
  60        long time;
  61#endif
  62
  63        local_irq_save(flags);
  64
  65        mic_tm_regs = cbe_get_cpu_mic_tm_regs(cpu);
  66        pmd_regs = cbe_get_cpu_pmd_regs(cpu);
  67
  68#ifdef DEBUG
  69        time = jiffies;
  70#endif
  71
  72        out_be64(&mic_tm_regs->slow_fast_timer_0, MIC_Slow_Fast_Timer_table[pmode]);
  73        out_be64(&mic_tm_regs->slow_fast_timer_1, MIC_Slow_Fast_Timer_table[pmode]);
  74
  75        out_be64(&mic_tm_regs->slow_next_timer_0, MIC_Slow_Next_Timer_table[pmode]);
  76        out_be64(&mic_tm_regs->slow_next_timer_1, MIC_Slow_Next_Timer_table[pmode]);
  77
  78        value = in_be64(&pmd_regs->pmcr);
  79        /* set bits to zero */
  80        value &= 0xFFFFFFFFFFFFFFF8ull;
  81        /* set bits to next pmode */
  82        value |= pmode;
  83
  84        out_be64(&pmd_regs->pmcr, value);
  85
  86#ifdef DEBUG
  87        /* wait until new pmode appears in status register */
  88        value = in_be64(&pmd_regs->pmsr) & 0x07;
  89        while (value != pmode) {
  90                cpu_relax();
  91                value = in_be64(&pmd_regs->pmsr) & 0x07;
  92        }
  93
  94        time = jiffies  - time;
  95        time = jiffies_to_msecs(time);
  96        pr_debug("had to wait %lu ms for a transition using " \
  97                 "pervasive unit\n", time);
  98#endif
  99        local_irq_restore(flags);
 100
 101        return 0;
 102}
 103
 104
 105int cbe_cpufreq_get_pmode(int cpu)
 106{
 107        int ret;
 108        struct cbe_pmd_regs __iomem *pmd_regs;
 109
 110        pmd_regs = cbe_get_cpu_pmd_regs(cpu);
 111        ret = in_be64(&pmd_regs->pmsr) & 0x07;
 112
 113        return ret;
 114}
 115
 116
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