2 * Copyright (C) 2000,2001,2004 Broadcom Corporation
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.
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.
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.
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.)
28 #include <linux/clockchips.h>
29 #include <linux/interrupt.h>
30 #include <linux/percpu.h>
31 #include <linux/spinlock.h>
34 #include <asm/addrspace.h>
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>
43 #include <asm/sibyte/sb1250.h>
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
50 #ifdef CONFIG_SIMULATION
51 #define BCM1480_HPT_VALUE 50000
53 #define BCM1480_HPT_VALUE 1000000
56 extern int bcm1480_steal_irq(int irq);
58 void __init plat_time_init(void)
60 unsigned int cpu = smp_processor_id();
61 unsigned int irq = K_BCM1480_INT_TIMER_0 + cpu;
63 BUG_ON(cpu > 3); /* Only have 4 general purpose timers */
65 bcm1480_mask_irq(cpu, irq);
67 /* Map the timer interrupt to ip[4] of this cpu */
68 __raw_writeq(IMR_IP4_VAL, IOADDR(A_BCM1480_IMR_REGISTER(cpu, R_BCM1480_IMR_INTERRUPT_MAP_BASE_H)
71 bcm1480_unmask_irq(cpu, irq);
72 bcm1480_steal_irq(irq);
76 * The general purpose timer ticks at 1 Mhz independent if
77 * the rest of the system
79 static void sibyte_set_mode(enum clock_event_mode mode,
80 struct clock_event_device *evt)
82 unsigned int cpu = smp_processor_id();
83 void __iomem *timer_cfg, *timer_init;
85 timer_cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
86 timer_init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));
89 case CLOCK_EVT_MODE_PERIODIC:
90 __raw_writeq(0, timer_cfg);
91 __raw_writeq(BCM1480_HPT_VALUE / HZ - 1, timer_init);
92 __raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
96 case CLOCK_EVT_MODE_ONESHOT:
97 /* Stop the timer until we actually program a shot */
98 case CLOCK_EVT_MODE_SHUTDOWN:
99 __raw_writeq(0, timer_cfg);
102 case CLOCK_EVT_MODE_UNUSED: /* shuddup gcc */
103 case CLOCK_EVT_MODE_RESUME:
108 static int sibyte_next_event(unsigned long delta, struct clock_event_device *cd)
110 unsigned int cpu = smp_processor_id();
111 void __iomem *timer_init;
115 timer_init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));
116 cnt = __raw_readq(timer_init);
118 __raw_writeq(cnt, timer_init);
119 res = ((long)(__raw_readq(timer_init) - cnt ) > 0) ? -ETIME : 0;
124 static DEFINE_PER_CPU(struct clock_event_device, sibyte_hpt_clockevent);
126 static irqreturn_t sibyte_counter_handler(int irq, void *dev_id)
128 unsigned int cpu = smp_processor_id();
129 struct clock_event_device *cd = &per_cpu(sibyte_hpt_clockevent, cpu);
131 /* Reset the timer */
132 __raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
133 IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
134 cd->event_handler(cd);
139 static struct irqaction sibyte_counter_irqaction = {
140 .handler = sibyte_counter_handler,
141 .flags = IRQF_DISABLED | IRQF_PERCPU,
146 * This interrupt is "special" in that it doesn't use the request_irq
147 * way to hook the irq line. The timer interrupt is initialized early
148 * enough to make this a major pain, and it's also firing enough to
149 * warrant a bit of special case code. bcm1480_timer_interrupt is
150 * called directly from irq_handler.S when IP[4] is set during an
153 void __cpuinit sb1480_clockevent_init(void)
155 unsigned int cpu = smp_processor_id();
156 unsigned int irq = K_BCM1480_INT_TIMER_0 + cpu;
157 struct clock_event_device *cd = &per_cpu(sibyte_hpt_clockevent, cpu);
159 cd->name = "bcm1480-counter";
160 cd->features = CLOCK_EVT_FEAT_PERIODIC |
161 CLOCK_EVT_MODE_ONESHOT;
162 cd->set_next_event = sibyte_next_event;
163 cd->set_mode = sibyte_set_mode;
165 clockevent_set_clock(cd, BCM1480_HPT_VALUE);
167 setup_irq(irq, &sibyte_counter_irqaction);
170 static cycle_t bcm1480_hpt_read(void)
172 /* We assume this function is called xtime_lock held. */
173 unsigned long count =
174 __raw_readq(IOADDR(A_SCD_TIMER_REGISTER(0, R_SCD_TIMER_CNT)));
175 return (jiffies + 1) * (BCM1480_HPT_VALUE / HZ) - count;
178 struct clocksource bcm1480_clocksource = {
181 .read = bcm1480_hpt_read,
182 .mask = CLOCKSOURCE_MASK(32),
184 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
187 void __init sb1480_clocksource_init(void)
189 struct clocksource *cs = &bcm1480_clocksource;
191 clocksource_set_clock(cs, BCM1480_HPT_VALUE);
192 clocksource_register(cs);
195 void __init bcm1480_hpt_setup(void)
197 mips_hpt_frequency = BCM1480_HPT_VALUE;
198 sb1480_clocksource_init();
199 sb1480_clockevent_init();