clock-sh3.c

linux 内核源代码

/*
 * arch/sh/kernel/cpu/sh3/clock-sh3.c
 *
 * Generic SH-3 support for the clock framework
 *
 *  Copyright (C) 2005  Paul Mundt
 *
 * FRQCR parsing hacked out of arch/sh/kernel/time.c
 *
 *  Copyright (C) 1999  Tetsuya Okada & Niibe Yutaka
 *  Copyright (C) 2000  Philipp Rumpf <[e-mail]>
 *  Copyright (C) 2002, 2003, 2004  Paul Mundt
 *  Copyright (C) 2002  M. R. Brown  <[e-mail]>
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/init.h>
#include <linux/kernel.h>
#include <asm/clock.h>
#include <asm/freq.h>
#include <asm/io.h>

static int stc_multipliers[] = { 1, 2, 3, 4, 6, 1, 1, 1 };
static int ifc_divisors[]    = { 1, 2, 3, 4, 1, 1, 1, 1 };
static int pfc_divisors[]    = { 1, 2, 3, 4, 6, 1, 1, 1 };

static void master_clk_init(struct clk *clk)
{
	int frqcr = ctrl_inw(FRQCR);
	int idx = ((frqcr & 0x2000) >> 11) | (frqcr & 0x0003);

	clk->rate *= pfc_divisors[idx];
}

static struct clk_ops sh3_master_clk_ops = {
	.init		= master_clk_init,
};

static void module_clk_recalc(struct clk *clk)
{
	int frqcr = ctrl_inw(FRQCR);
	int idx = ((frqcr & 0x2000) >> 11) | (frqcr & 0x0003);

	clk->rate = clk->parent->rate / pfc_divisors[idx];
}

static struct clk_ops sh3_module_clk_ops = {
	.recalc		= module_clk_recalc,
};

static void bus_clk_recalc(struct clk *clk)
{
	int frqcr = ctrl_inw(FRQCR);
	int idx = ((frqcr & 0x8000) >> 13) | ((frqcr & 0x0030) >> 4);

	clk->rate = clk->parent->rate / stc_multipliers[idx];
}

static struct clk_ops sh3_bus_clk_ops = {
	.recalc		= bus_clk_recalc,
};

static void cpu_clk_recalc(struct clk *clk)
{
	int frqcr = ctrl_inw(FRQCR);
	int idx = ((frqcr & 0x4000) >> 12) | ((frqcr & 0x000c) >> 2);

	clk->rate = clk->parent->rate / ifc_divisors[idx];
}

static struct clk_ops sh3_cpu_clk_ops = {
	.recalc		= cpu_clk_recalc,
};

static struct clk_ops *sh3_clk_ops[] = {
	&sh3_master_clk_ops,
	&sh3_module_clk_ops,
	&sh3_bus_clk_ops,
	&sh3_cpu_clk_ops,
};

void __init arch_init_clk_ops(struct clk_ops **ops, int idx)
{
	if (idx < ARRAY_SIZE(sh3_clk_ops))
		*ops = sh3_clk_ops[idx];
}