csrc-powertv.c

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/*
 * Copyright (C) 2008 Scientific-Atlanta, Inc.
 *
 * 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
 * of the License, 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
/*
 * The file comes from kernel/csrc-r4k.c
 */
#include <linux/clocksource.h>
#include <linux/init.h>

#include <asm/time.h>           /* Not included in linux/time.h */

#include <asm/mach-powertv/asic_regs.h>
#include "powertv-clock.h"

/* MIPS PLL Register Definitions */
#define PLL_GET_M(x)        (((x) >> 8) & 0x000000FF)
#define PLL_GET_N(x)        (((x) >> 16) & 0x000000FF)
#define PLL_GET_P(x)        (((x) >> 24) & 0x00000007)

/*
 * returns:  Clock frequency in kHz
 */
unsigned int __init mips_get_pll_freq(void)
{
    unsigned int pll_reg, m, n, p;
    unsigned int fin = 54000; /* Base frequency in kHz */
    unsigned int fout;

    /* Read PLL register setting */
    pll_reg = asic_read(mips_pll_setup);
    m = PLL_GET_M(pll_reg);
    n = PLL_GET_N(pll_reg);
    p = PLL_GET_P(pll_reg);
    pr_info("MIPS PLL Register:0x%x  M=%d  N=%d  P=%d\n", pll_reg, m, n, p);

    /* Calculate clock frequency = (2 * N * 54MHz) / (M * (2**P)) */
    fout = ((2 * n * fin) / (m * (0x01 << p)));

    pr_info("MIPS Clock Freq=%d kHz\n", fout);

    return fout;
}

static cycle_t c0_hpt_read(struct clocksource *cs)
{
    return read_c0_count();
}

static struct clocksource clocksource_mips = {
    .name       = "powertv-counter",
    .read       = c0_hpt_read,
    .mask       = CLOCKSOURCE_MASK(32),
    .flags      = CLOCK_SOURCE_IS_CONTINUOUS,
};

static void __init powertv_c0_hpt_clocksource_init(void)
{
    unsigned int pll_freq = mips_get_pll_freq();

    pr_info("CPU frequency %d.%02d MHz\n", pll_freq / 1000,
        (pll_freq % 1000) * 100 / 1000);

    mips_hpt_frequency = pll_freq / 2 * 1000;

    clocksource_mips.rating = 200 + mips_hpt_frequency / 10000000;

    clocksource_register_hz(&clocksource_mips, mips_hpt_frequency);
}

struct tim_c {
    unsigned int hi;
    unsigned int lo;
};

static struct tim_c *tim_c;

static cycle_t tim_c_read(struct clocksource *cs)
{
    unsigned int hi;
    unsigned int next_hi;
    unsigned int lo;

    hi = readl(&tim_c->hi);

    for (;;) {
        lo = readl(&tim_c->lo);
        next_hi = readl(&tim_c->hi);
        if (next_hi == hi)
            break;
        hi = next_hi;
    }

pr_crit("%s: read %llx\n", __func__, ((u64) hi << 32) | lo);
    return ((u64) hi << 32) | lo;
}

#define TIM_C_SIZE      48      /* # bits in the timer */

static struct clocksource clocksource_tim_c = {
    .name       = "powertv-tim_c",
    .read       = tim_c_read,
    .mask       = CLOCKSOURCE_MASK(TIM_C_SIZE),
    .flags      = CLOCK_SOURCE_IS_CONTINUOUS,
};

static void __init powertv_tim_c_clocksource_init(void)
{
    const unsigned long counts_per_second = 27000000 / 8;

    clocksource_tim_c.rating = 200;

    clocksource_register_hz(&clocksource_tim_c, counts_per_second);
    tim_c = (struct tim_c *) asic_reg_addr(tim_ch);
}

void __init powertv_clocksource_init(void)
{
    powertv_c0_hpt_clocksource_init();
    powertv_tim_c_clocksource_init();
}