aboutsummaryrefslogtreecommitdiff
path: root/arch/mips/kernel/cevt-sb1250.c
blob: 200f2778bf3660f8acb6cbc4b9eef72f37f0418e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
/*
 * Copyright (C) 2000, 2001 Broadcom Corporation
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
#include <linux/clockchips.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/percpu.h>
#include <linux/smp.h>

#include <asm/addrspace.h>
#include <asm/io.h>
#include <asm/time.h>

#include <asm/sibyte/sb1250.h>
#include <asm/sibyte/sb1250_regs.h>
#include <asm/sibyte/sb1250_int.h>
#include <asm/sibyte/sb1250_scd.h>

#define IMR_IP2_VAL	K_INT_MAP_I0
#define IMR_IP3_VAL	K_INT_MAP_I1
#define IMR_IP4_VAL	K_INT_MAP_I2

/*
 * The general purpose timer ticks at 1MHz independent if
 * the rest of the system
 */
static void sibyte_set_mode(enum clock_event_mode mode,
			   struct clock_event_device *evt)
{
	unsigned int cpu = smp_processor_id();
	void __iomem *cfg, *init;

	cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
	init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));

	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
		__raw_writeq(0, cfg);
		__raw_writeq((V_SCD_TIMER_FREQ / HZ) - 1, init);
		__raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
			     cfg);
		break;

	case CLOCK_EVT_MODE_ONESHOT:
		/* Stop the timer until we actually program a shot */
	case CLOCK_EVT_MODE_SHUTDOWN:
		__raw_writeq(0, cfg);
		break;

	case CLOCK_EVT_MODE_UNUSED:	/* shuddup gcc */
	case CLOCK_EVT_MODE_RESUME:
		;
	}
}

static int sibyte_next_event(unsigned long delta, struct clock_event_device *cd)
{
	unsigned int cpu = smp_processor_id();
	void __iomem *cfg, *init;

	cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
	init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));

	__raw_writeq(0, cfg);
	__raw_writeq(delta - 1, init);
	__raw_writeq(M_SCD_TIMER_ENABLE, cfg);

	return 0;
}

static irqreturn_t sibyte_counter_handler(int irq, void *dev_id)
{
	unsigned int cpu = smp_processor_id();
	struct clock_event_device *cd = dev_id;
	void __iomem *cfg;
	unsigned long tmode;

	if (cd->mode == CLOCK_EVT_MODE_PERIODIC)
		tmode = M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS;
	else
		tmode = 0;

	/* ACK interrupt */
	cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
	____raw_writeq(tmode, cfg);

	cd->event_handler(cd);

	return IRQ_HANDLED;
}

static DEFINE_PER_CPU(struct clock_event_device, sibyte_hpt_clockevent);
static DEFINE_PER_CPU(struct irqaction, sibyte_hpt_irqaction);
static DEFINE_PER_CPU(char [18], sibyte_hpt_name);

void __cpuinit sb1250_clockevent_init(void)
{
	unsigned int cpu = smp_processor_id();
	unsigned int irq = K_INT_TIMER_0 + cpu;
	struct irqaction *action = &per_cpu(sibyte_hpt_irqaction, cpu);
	struct clock_event_device *cd = &per_cpu(sibyte_hpt_clockevent, cpu);
	unsigned char *name = per_cpu(sibyte_hpt_name, cpu);

	/* Only have 4 general purpose timers, and we use last one as hpt */
	BUG_ON(cpu > 2);

	sprintf(name, "sb1250-counter-%d", cpu);
	cd->name		= name;
	cd->features		= CLOCK_EVT_FEAT_PERIODIC |
				  CLOCK_EVT_FEAT_ONESHOT;
	clockevent_set_clock(cd, V_SCD_TIMER_FREQ);
	cd->max_delta_ns	= clockevent_delta2ns(0x7fffff, cd);
	cd->min_delta_ns	= clockevent_delta2ns(2, cd);
	cd->rating		= 200;
	cd->irq			= irq;
	cd->cpumask		= cpumask_of(cpu);
	cd->set_next_event	= sibyte_next_event;
	cd->set_mode		= sibyte_set_mode;
	clockevents_register_device(cd);

	sb1250_mask_irq(cpu, irq);

	/*
	 * Map the timer interrupt to IP[4] of this cpu
	 */
	__raw_writeq(IMR_IP4_VAL,
		     IOADDR(A_IMR_REGISTER(cpu, R_IMR_INTERRUPT_MAP_BASE) +
			    (irq << 3)));

	sb1250_unmask_irq(cpu, irq);

	action->handler = sibyte_counter_handler;
	action->flags	= IRQF_PERCPU | IRQF_TIMER;
	action->name	= name;
	action->dev_id	= cd;

	irq_set_affinity(irq, cpumask_of(cpu));
	setup_irq(irq, action);
}