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cbe_cpufreq_pervasive.c

/*
 * pervasive backend for the cbe_cpufreq driver
 *
 * This driver makes use of the pervasive unit to
 * engage the desired frequency.
 *
 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
 *
 * Author: Christian Krafft <krafft@de.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <asm/machdep.h>
#include <asm/hw_irq.h>
#include <asm/cell-regs.h>

#include "cbe_cpufreq.h"

/* to write to MIC register */
static u64 MIC_Slow_Fast_Timer_table[] = {
      [0 ... 7] = 0x007fc00000000000ull,
};

/* more values for the MIC */
static u64 MIC_Slow_Next_Timer_table[] = {
      0x0000240000000000ull,
      0x0000268000000000ull,
      0x000029C000000000ull,
      0x00002D0000000000ull,
      0x0000300000000000ull,
      0x0000334000000000ull,
      0x000039C000000000ull,
      0x00003FC000000000ull,
};


int cbe_cpufreq_set_pmode(int cpu, unsigned int pmode)
{
      struct cbe_pmd_regs __iomem *pmd_regs;
      struct cbe_mic_tm_regs __iomem *mic_tm_regs;
      u64 flags;
      u64 value;
#ifdef DEBUG
      long time;
#endif

      local_irq_save(flags);

      mic_tm_regs = cbe_get_cpu_mic_tm_regs(cpu);
      pmd_regs = cbe_get_cpu_pmd_regs(cpu);

#ifdef DEBUG
      time = jiffies;
#endif

      out_be64(&mic_tm_regs->slow_fast_timer_0, MIC_Slow_Fast_Timer_table[pmode]);
      out_be64(&mic_tm_regs->slow_fast_timer_1, MIC_Slow_Fast_Timer_table[pmode]);

      out_be64(&mic_tm_regs->slow_next_timer_0, MIC_Slow_Next_Timer_table[pmode]);
      out_be64(&mic_tm_regs->slow_next_timer_1, MIC_Slow_Next_Timer_table[pmode]);

      value = in_be64(&pmd_regs->pmcr);
      /* set bits to zero */
      value &= 0xFFFFFFFFFFFFFFF8ull;
      /* set bits to next pmode */
      value |= pmode;

      out_be64(&pmd_regs->pmcr, value);

#ifdef DEBUG
      /* wait until new pmode appears in status register */
      value = in_be64(&pmd_regs->pmsr) & 0x07;
      while (value != pmode) {
            cpu_relax();
            value = in_be64(&pmd_regs->pmsr) & 0x07;
      }

      time = jiffies  - time;
      time = jiffies_to_msecs(time);
      pr_debug("had to wait %lu ms for a transition using " \
             "pervasive unit\n", time);
#endif
      local_irq_restore(flags);

      return 0;
}


int cbe_cpufreq_get_pmode(int cpu)
{
      int ret;
      struct cbe_pmd_regs __iomem *pmd_regs;

      pmd_regs = cbe_get_cpu_pmd_regs(cpu);
      ret = in_be64(&pmd_regs->pmsr) & 0x07;

      return ret;
}


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