1/*
  2 * Copyright (C) 2008 Scientific-Atlanta, Inc.
  3 *
  4 * This program is free software; you can redistribute it and/or
  5 * modify it under the terms of the GNU General Public License
  6 * as published by the Free Software Foundation; either version 2
  7 * of the License, or (at your option) any later version.
  8 *
  9 * This program is distributed in the hope that it will be useful,
 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12 * GNU General Public License for more details.
 13 *
 14 * You should have received a copy of the GNU General Public License
 15 * along with this program; if not, write to the Free Software
 16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 17 */
 18/*
 19 * The file comes from kernel/csrc-r4k.c
 20 */
 21#include <linux/clocksource.h>
 22#include <linux/init.h>
 23
 24#include <asm/time.h>			/* Not included in linux/time.h */
 25
 26#include <asm/mach-powertv/asic_regs.h>
 27#include "powertv-clock.h"
 28
 29/* MIPS PLL Register Definitions */
 30#define PLL_GET_M(x)		(((x) >> 8) & 0x000000FF)
 31#define PLL_GET_N(x)		(((x) >> 16) & 0x000000FF)
 32#define PLL_GET_P(x)		(((x) >> 24) & 0x00000007)
 33
 34/*
 35 * returns:  Clock frequency in kHz
 36 */
 37unsigned int __init mips_get_pll_freq(void)
 38{
 39	unsigned int pll_reg, m, n, p;
 40	unsigned int fin = 54000; /* Base frequency in kHz */
 41	unsigned int fout;
 42
 43	/* Read PLL register setting */
 44	pll_reg = asic_read(mips_pll_setup);
 45	m = PLL_GET_M(pll_reg);
 46	n = PLL_GET_N(pll_reg);
 47	p = PLL_GET_P(pll_reg);
 48	pr_info("MIPS PLL Register:0x%x  M=%d  N=%d  P=%d\n", pll_reg, m, n, p);
 49
 50	/* Calculate clock frequency = (2 * N * 54MHz) / (M * (2**P)) */
 51	fout = ((2 * n * fin) / (m * (0x01 << p)));
 52
 53	pr_info("MIPS Clock Freq=%d kHz\n", fout);
 54
 55	return fout;
 56}
 57
 58static cycle_t c0_hpt_read(struct clocksource *cs)
 59{
 60	return read_c0_count();
 61}
 62
 63static struct clocksource clocksource_mips = {
 64	.name		= "powertv-counter",
 65	.read		= c0_hpt_read,
 66	.mask		= CLOCKSOURCE_MASK(32),
 67	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 68};
 69
 70static void __init powertv_c0_hpt_clocksource_init(void)
 71{
 72	unsigned int pll_freq = mips_get_pll_freq();
 73
 74	pr_info("CPU frequency %d.%02d MHz\n", pll_freq / 1000,
 75		(pll_freq % 1000) * 100 / 1000);
 76
 77	mips_hpt_frequency = pll_freq / 2 * 1000;
 78
 79	clocksource_mips.rating = 200 + mips_hpt_frequency / 10000000;
 80
 81	clocksource_register_hz(&clocksource_mips, mips_hpt_frequency);
 82}
 83
 84/**
 85 * struct tim_c - free running counter
 86 * @hi:	High 16 bits of the counter
 87 * @lo:	Low 32 bits of the counter
 88 *
 89 * Lays out the structure of the free running counter in memory. This counter
 90 * increments at a rate of 27 MHz/8 on all platforms.
 91 */
 92struct tim_c {
 93	unsigned int hi;
 94	unsigned int lo;
 95};
 96
 97static struct tim_c *tim_c;
 98
 99static cycle_t tim_c_read(struct clocksource *cs)
100{
101	unsigned int hi;
102	unsigned int next_hi;
103	unsigned int lo;
104
105	hi = readl(&tim_c->hi);
106
107	for (;;) {
108		lo = readl(&tim_c->lo);
109		next_hi = readl(&tim_c->hi);
110		if (next_hi == hi)
111			break;
112		hi = next_hi;
113	}
114
115pr_crit("%s: read %llx\n", __func__, ((u64) hi << 32) | lo);
116	return ((u64) hi << 32) | lo;
117}
118
119#define TIM_C_SIZE		48		/* # bits in the timer */
120
121static struct clocksource clocksource_tim_c = {
122	.name		= "powertv-tim_c",
123	.read		= tim_c_read,
124	.mask		= CLOCKSOURCE_MASK(TIM_C_SIZE),
125	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
126};
127
128/**
129 * powertv_tim_c_clocksource_init - set up a clock source for the TIM_C clock
130 *
131 * We know that TIM_C counts at 27 MHz/8, so each cycle corresponds to
132 * 1 / (27,000,000/8) seconds.
133 */
134static void __init powertv_tim_c_clocksource_init(void)
135{
136	const unsigned long	counts_per_second = 27000000 / 8;
137
138	clocksource_tim_c.rating = 200;
139
140	clocksource_register_hz(&clocksource_tim_c, counts_per_second);
141	tim_c = (struct tim_c *) asic_reg_addr(tim_ch);
142}
143
144/**
145 powertv_clocksource_init - initialize all clocksources
146 */
147void __init powertv_clocksource_init(void)
148{
149	powertv_c0_hpt_clocksource_init();
150	powertv_tim_c_clocksource_init();
151}