1/*
2 * Copyright (C) 2000,2001,2004 Broadcom Corporation
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/*
20 * These are routines to set up and handle interrupts from the
21 * bcm1480 general purpose timer 0.  We're using the timer as a
22 * system clock, so we set it up to run at 100 Hz.  On every
23 * interrupt, we update our idea of what the time of day is,
24 * then call do_timer() in the architecture-independent kernel
25 * code to do general bookkeeping (e.g. update jiffies, run
26 * bottom halves, etc.)
27 */
28#include <linux/interrupt.h>
29#include <linux/sched.h>
30#include <linux/spinlock.h>
31#include <linux/kernel_stat.h>
32
33#include <asm/irq.h>
34#include <asm/addrspace.h>
35#include <asm/time.h>
36#include <asm/io.h>
37
38#include <asm/sibyte/bcm1480_regs.h>
39#include <asm/sibyte/sb1250_regs.h>
40#include <asm/sibyte/bcm1480_int.h>
41#include <asm/sibyte/bcm1480_scd.h>
42
43#include <asm/sibyte/sb1250.h>
44
45
46#define IMR_IP2_VAL	K_BCM1480_INT_MAP_I0
47#define IMR_IP3_VAL	K_BCM1480_INT_MAP_I1
48#define IMR_IP4_VAL	K_BCM1480_INT_MAP_I2
49
50#ifdef CONFIG_SIMULATION
51#define BCM1480_HPT_VALUE	50000
52#else
53#define BCM1480_HPT_VALUE	1000000
54#endif
55
56extern int bcm1480_steal_irq(int irq);
57
58void bcm1480_time_init(void)
59{
60	int cpu = smp_processor_id();
61	int irq = K_BCM1480_INT_TIMER_0+cpu;
62
63	/* Only have 4 general purpose timers */
64	if (cpu > 3) {
65		BUG();
66	}
67
68	bcm1480_mask_irq(cpu, irq);
69
70	/* Map the timer interrupt to ip[4] of this cpu */
71	__raw_writeq(IMR_IP4_VAL, IOADDR(A_BCM1480_IMR_REGISTER(cpu, R_BCM1480_IMR_INTERRUPT_MAP_BASE_H)
72	      + (irq<<3)));
73
74	/* the general purpose timer ticks at 1 Mhz independent of the rest of the system */
75	/* Disable the timer and set up the count */
76	__raw_writeq(0, IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
77	__raw_writeq(
78		BCM1480_HPT_VALUE/HZ
79		, IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT)));
80
81	/* Set the timer running */
82	__raw_writeq(M_SCD_TIMER_ENABLE|M_SCD_TIMER_MODE_CONTINUOUS,
83	      IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
84
85	bcm1480_unmask_irq(cpu, irq);
86	bcm1480_steal_irq(irq);
87	/*
88	 * This interrupt is "special" in that it doesn't use the request_irq
89	 * way to hook the irq line.  The timer interrupt is initialized early
90	 * enough to make this a major pain, and it's also firing enough to
91	 * warrant a bit of special case code.  bcm1480_timer_interrupt is
92	 * called directly from irq_handler.S when IP[4] is set during an
93	 * interrupt
94	 */
95}
96
97void bcm1480_timer_interrupt(void)
98{
99	int cpu = smp_processor_id();
100	int irq = K_BCM1480_INT_TIMER_0 + cpu;
101
102	/* Reset the timer */
103	__raw_writeq(M_SCD_TIMER_ENABLE|M_SCD_TIMER_MODE_CONTINUOUS,
104	      IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
105
106	if (cpu == 0) {
107		/*
108		 * CPU 0 handles the global timer interrupt job
109		 */
110		ll_timer_interrupt(irq);
111	}
112	else {
113		/*
114		 * other CPUs should just do profiling and process accounting
115		 */
116		ll_local_timer_interrupt(irq);
117	}
118}
119
120static cycle_t bcm1480_hpt_read(void)
121{
122	/* We assume this function is called xtime_lock held. */
123	unsigned long count =
124		__raw_readq(IOADDR(A_SCD_TIMER_REGISTER(0, R_SCD_TIMER_CNT)));
125	return (jiffies + 1) * (BCM1480_HPT_VALUE / HZ) - count;
126}
127
128void __init bcm1480_hpt_setup(void)
129{
130	clocksource_mips.read = bcm1480_hpt_read;
131	mips_hpt_frequency = BCM1480_HPT_VALUE;
132}
133