2 * Copyright (C) 2000, 2001 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 * sb1250 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/interrupt.h>
29 #include <linux/sched.h>
30 #include <linux/spinlock.h>
31 #include <linux/kernel_stat.h>
34 #include <asm/ptrace.h>
35 #include <asm/addrspace.h>
39 #include <asm/sibyte/sb1250.h>
40 #include <asm/sibyte/sb1250_regs.h>
41 #include <asm/sibyte/sb1250_int.h>
42 #include <asm/sibyte/sb1250_scd.h>
45 #define IMR_IP2_VAL K_INT_MAP_I0
46 #define IMR_IP3_VAL K_INT_MAP_I1
47 #define IMR_IP4_VAL K_INT_MAP_I2
49 #define SB1250_HPT_NUM 3
50 #define SB1250_HPT_VALUE M_SCD_TIMER_CNT /* max value */
51 #define SB1250_HPT_SHIFT ((sizeof(unsigned int)*8)-V_SCD_TIMER_WIDTH)
54 extern int sb1250_steal_irq(int irq
);
56 static unsigned int sb1250_hpt_read(void);
57 static void sb1250_hpt_init(unsigned int);
59 static unsigned int hpt_offset
;
61 void __init
sb1250_hpt_setup(void)
63 int cpu
= smp_processor_id();
66 /* Setup hpt using timer #3 but do not enable irq for it */
67 __raw_writeq(0, IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM
, R_SCD_TIMER_CFG
)));
68 __raw_writeq(SB1250_HPT_VALUE
,
69 IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM
, R_SCD_TIMER_INIT
)));
70 __raw_writeq(M_SCD_TIMER_ENABLE
| M_SCD_TIMER_MODE_CONTINUOUS
,
71 IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM
, R_SCD_TIMER_CFG
)));
74 * we need to fill 32 bits, so just use the upper 23 bits and pretend
75 * the timer is going 512Mhz instead of 1Mhz
77 mips_hpt_frequency
= V_SCD_TIMER_FREQ
<< SB1250_HPT_SHIFT
;
78 mips_hpt_init
= sb1250_hpt_init
;
79 mips_hpt_read
= sb1250_hpt_read
;
84 void sb1250_time_init(void)
86 int cpu
= smp_processor_id();
87 int irq
= K_INT_TIMER_0
+cpu
;
89 /* Only have 4 general purpose timers, and we use last one as hpt */
94 sb1250_mask_irq(cpu
, irq
);
96 /* Map the timer interrupt to ip[4] of this cpu */
97 __raw_writeq(IMR_IP4_VAL
,
98 IOADDR(A_IMR_REGISTER(cpu
, R_IMR_INTERRUPT_MAP_BASE
) +
101 /* the general purpose timer ticks at 1 Mhz independent if the rest of the system */
102 /* Disable the timer and set up the count */
103 __raw_writeq(0, IOADDR(A_SCD_TIMER_REGISTER(cpu
, R_SCD_TIMER_CFG
)));
104 #ifdef CONFIG_SIMULATION
105 __raw_writeq((50000 / HZ
) - 1,
106 IOADDR(A_SCD_TIMER_REGISTER(cpu
, R_SCD_TIMER_INIT
)));
108 __raw_writeq((V_SCD_TIMER_FREQ
/ HZ
) - 1,
109 IOADDR(A_SCD_TIMER_REGISTER(cpu
, R_SCD_TIMER_INIT
)));
112 /* Set the timer running */
113 __raw_writeq(M_SCD_TIMER_ENABLE
| M_SCD_TIMER_MODE_CONTINUOUS
,
114 IOADDR(A_SCD_TIMER_REGISTER(cpu
, R_SCD_TIMER_CFG
)));
116 sb1250_unmask_irq(cpu
, irq
);
117 sb1250_steal_irq(irq
);
119 * This interrupt is "special" in that it doesn't use the request_irq
120 * way to hook the irq line. The timer interrupt is initialized early
121 * enough to make this a major pain, and it's also firing enough to
122 * warrant a bit of special case code. sb1250_timer_interrupt is
123 * called directly from irq_handler.S when IP[4] is set during an
128 void sb1250_timer_interrupt(struct pt_regs
*regs
)
130 int cpu
= smp_processor_id();
131 int irq
= K_INT_TIMER_0
+ cpu
;
134 ____raw_writeq(M_SCD_TIMER_ENABLE
| M_SCD_TIMER_MODE_CONTINUOUS
,
135 IOADDR(A_SCD_TIMER_REGISTER(cpu
, R_SCD_TIMER_CFG
)));
139 * CPU 0 handles the global timer interrupt job
141 ll_timer_interrupt(irq
, regs
);
145 * other CPUs should just do profiling and process accounting
147 ll_local_timer_interrupt(irq
, regs
);
152 * The HPT is free running from SB1250_HPT_VALUE down to 0 then starts over
153 * again. There's no easy way to set to a specific value so store init value
154 * in hpt_offset and subtract each time.
156 * Note: Timer isn't full 32bits so shift it into the upper part making
157 * it appear to run at a higher frequency.
159 static unsigned int sb1250_hpt_read(void)
163 count
= G_SCD_TIMER_CNT(__raw_readq(IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM
, R_SCD_TIMER_CNT
))));
165 count
= (SB1250_HPT_VALUE
- count
) << SB1250_HPT_SHIFT
;
167 return count
- hpt_offset
;
170 static void sb1250_hpt_init(unsigned int count
)