s3c2410.c

/* S3C2410 register manipulating module

Copyright (C) 2016 Arnie97

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.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

*/

#include "s3c2410.h"

const unsigned valid_mpllcon_values[] = {
	// custom value
	0x34023,

	// from PLL value selection table in S3C2410 datasheet
	0x52023, 0x52013, 0x78023, 0xa1033, 0x8e023, 0x52022,

	// hp default
	0x43012,

	0x47012, 0x69022, 0x70022, 0x7f022, 0x69012, 0x96022,
	0x74012, 0x52021, 0x5a021, 0x44011, 0x47011, 0x4d011,
	0x55011, 0x58011, 0xa1031, 0
};


inline float
mpllcon_to_freq(struct mpllcon *reg, unsigned fin)
{
	unsigned
		m = reg->mdiv + 8,
		p = reg->pdiv + 2,
		s = reg->sdiv;

	return (float)fin * m / (p << s);
}


int
is_valid_mpllcon(unsigned *reg)
{
	// iterate over mpllcon values
	// and return on the first match
	for (unsigned *p = valid_mpllcon_values; *p; p++) {
		if (*reg == *p) {
			// if mpll is set to hp default, return 1
			// otherwise, return 2
			return p == valid_mpllcon_values + 7? 1: 2;
		}
	}

	return 0;
}


inline float
clkslow_to_freq(struct clkslow *reg, unsigned fin)
{
	if (reg->slow_bit) {
		// slow mode
		if (reg->slow_val) {
			return (float)fin / (2 * reg->slow_val);
		}
		return fin;
	} else {
		// normal mode
		return 0;
	}
}


inline unsigned
freq_to_access_cycle(unsigned freq)
{
	unsigned desired_clock = freq / 24;
	const char clocks[] = {1, 2, 3, 4, 6, 8, 10, 14};
	for (int i = 2; i < sizeof(clocks) / sizeof(*clocks); i++) {
		if (desired_clock <= clocks[i]) {
			return i;
		}
	}
}