path: root/arch/sh/kernel/cpu/sh4a/clock-sh7722.c

/*
 * arch/sh/kernel/cpu/sh4a/clock-sh7722.c
 *
 * SH7343, SH7722 & SH7366 support for the clock framework
 *
 * Copyright (c) 2006-2007 Nomad Global Solutions Inc
 * Based on code for sh7343 by Paul Mundt
 *
 * 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 <linux/io.h>
#include <linux/errno.h>
#include <linux/stringify.h>
#include <asm/clock.h>
#include <asm/freq.h>

#define N  (-1)
#define NM (-2)
#define ROUND_NEAREST 0
#define ROUND_DOWN -1
#define ROUND_UP   +1

static int adjust_algos[][3] = {
	{},	/* NO_CHANGE */
	{ NM, N, 1 },   /* N:1, N:1 */
	{ 3, 2, 2 },	/* 3:2:2 */
	{ 5, 2, 2 },    /* 5:2:2 */
	{ N, 1, 1 },	/* N:1:1 */

	{ N, 1 },	/* N:1 */

	{ N, 1 },	/* N:1 */
	{ 3, 2 },
	{ 4, 3 },
	{ 5, 4 },

	{ N, 1 }
};

static unsigned long adjust_pair_of_clocks(unsigned long r1, unsigned long r2,
			int m1, int m2, int round_flag)
{
	unsigned long rem, div;
	int the_one = 0;

	pr_debug( "Actual values: r1 = %ld\n", r1);
	pr_debug( "...............r2 = %ld\n", r2);

	if (m1 == m2) {
		r2 = r1;
		pr_debug( "setting equal rates: r2 now %ld\n", r2);
	} else if ((m2 == N  && m1 == 1) ||
		   (m2 == NM && m1 == N)) { /* N:1 or NM:N */
		pr_debug( "Setting rates as 1:N (N:N*M)\n");
		rem = r2 % r1;
		pr_debug( "...remainder = %ld\n", rem);
		if (rem) {
			div = r2 / r1;
			pr_debug( "...div = %ld\n", div);
			switch (round_flag) {
			case ROUND_NEAREST:
				the_one = rem >= r1/2 ? 1 : 0; break;
			case ROUND_UP:
				the_one = 1; break;
			case ROUND_DOWN:
				the_one = 0; break;
			}

			r2 = r1 * (div + the_one);
			pr_debug( "...setting r2 to %ld\n", r2);
		}
	} else if ((m2 == 1  && m1 == N) ||
		   (m2 == N && m1 == NM)) { /* 1:N or N:NM */
		pr_debug( "Setting rates as N:1 (N*M:N)\n");
		rem = r1 % r2;
		pr_debug( "...remainder = %ld\n", rem);
		if (rem) {
			div = r1 / r2;
			pr_debug( "...div = %ld\n", div);
			switch (round_flag) {
			case ROUND_NEAREST:
				the_one = rem > r2/2 ? 1 : 0; break;
			case ROUND_UP:
				the_one = 0; break;
			case ROUND_DOWN:
				the_one = 1; break;
			}

			r2 = r1 / (div + the_one);
			pr_debug( "...setting r2 to %ld\n", r2);
		}
	} else { /* value:value */
		pr_debug( "Setting rates as %d:%d\n", m1, m2);
		div = r1 / m1;
		r2 = div * m2;
		pr_debug( "...div = %ld\n", div);
		pr_debug( "...setting r2 to %ld\n", r2);
	}

	return r2;
}

static void adjust_clocks(int originate, int *l, unsigned long v[],
			  int n_in_line)
{
	int x;

	pr_debug( "Go down from %d...\n", originate);
	/* go up recalculation clocks */
	for (x = originate; x>0; x -- )
		v[x-1] = adjust_pair_of_clocks(v[x], v[x-1],
					l[x], l[x-1],
					ROUND_UP);

	pr_debug( "Go up from %d...\n", originate);
	/* go down recalculation clocks */
	for (x = originate; x<n_in_line - 1; x ++ )
		v[x+1] = adjust_pair_of_clocks(v[x], v[x+1],
					l[x], l[x+1],
					ROUND_UP);
}


/*
 * SH7722 uses a common set of multipliers and divisors, so this
 * is quite simple..
 */

#if defined(CONFIG_CPU_SUBTYPE_SH7724)
#define STCPLL(frqcr) ((((frqcr >> 24) & 0x3f) + 1) * 2)
#else
#define STCPLL(frqcr) (((frqcr >> 24) & 0x1f) + 1)
#endif

/*
 * Instead of having two separate multipliers/divisors set, like this:
 *
 * static int multipliers[] = { 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1 };
 * static int divisors[] = { 1, 3, 2, 5, 3, 4, 5, 6, 8, 10, 12, 16, 20 };
 *
 * I created the divisors2 array, which is used to calculate rate like
 *   rate = parent * 2 / divisors2[ divisor ];
*/
#if defined(CONFIG_CPU_SUBTYPE_SH7724)
static int divisors2[] = { 4, 1, 8, 12, 16, 24, 32, 1, 48, 64, 72, 96, 1, 144