cbe_cpufreq_pervasive.c

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/*
 * 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 <[email protected]>
 *
 * 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;
    unsigned long 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;
}