174 lines
5.1 KiB
C
174 lines
5.1 KiB
C
/*
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* Copyright (C) 2000, 2001 Broadcom Corporation
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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/*
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* These are routines to set up and handle interrupts from the
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* sb1250 general purpose timer 0. We're using the timer as a
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* system clock, so we set it up to run at 100 Hz. On every
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* interrupt, we update our idea of what the time of day is,
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* then call do_timer() in the architecture-independent kernel
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* code to do general bookkeeping (e.g. update jiffies, run
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* bottom halves, etc.)
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*/
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#include <linux/interrupt.h>
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#include <linux/sched.h>
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#include <linux/spinlock.h>
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#include <linux/kernel_stat.h>
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#include <asm/irq.h>
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#include <asm/addrspace.h>
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#include <asm/time.h>
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#include <asm/io.h>
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#include <asm/sibyte/sb1250.h>
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#include <asm/sibyte/sb1250_regs.h>
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#include <asm/sibyte/sb1250_int.h>
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#include <asm/sibyte/sb1250_scd.h>
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#define IMR_IP2_VAL K_INT_MAP_I0
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#define IMR_IP3_VAL K_INT_MAP_I1
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#define IMR_IP4_VAL K_INT_MAP_I2
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#define SB1250_HPT_NUM 3
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#define SB1250_HPT_VALUE M_SCD_TIMER_CNT /* max value */
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#define SB1250_HPT_SHIFT ((sizeof(unsigned int)*8)-V_SCD_TIMER_WIDTH)
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extern int sb1250_steal_irq(int irq);
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static unsigned int sb1250_hpt_read(void);
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static void sb1250_hpt_init(unsigned int);
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static unsigned int hpt_offset;
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void __init sb1250_hpt_setup(void)
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{
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int cpu = smp_processor_id();
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if (!cpu) {
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/* Setup hpt using timer #3 but do not enable irq for it */
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__raw_writeq(0, IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CFG)));
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__raw_writeq(SB1250_HPT_VALUE,
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IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_INIT)));
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__raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
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IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CFG)));
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/*
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* we need to fill 32 bits, so just use the upper 23 bits and pretend
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* the timer is going 512Mhz instead of 1Mhz
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*/
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mips_hpt_frequency = V_SCD_TIMER_FREQ << SB1250_HPT_SHIFT;
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mips_hpt_init = sb1250_hpt_init;
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mips_hpt_read = sb1250_hpt_read;
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}
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}
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void sb1250_time_init(void)
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{
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int cpu = smp_processor_id();
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int irq = K_INT_TIMER_0+cpu;
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/* Only have 4 general purpose timers, and we use last one as hpt */
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if (cpu > 2) {
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BUG();
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}
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sb1250_mask_irq(cpu, irq);
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/* Map the timer interrupt to ip[4] of this cpu */
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__raw_writeq(IMR_IP4_VAL,
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IOADDR(A_IMR_REGISTER(cpu, R_IMR_INTERRUPT_MAP_BASE) +
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(irq << 3)));
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/* the general purpose timer ticks at 1 Mhz independent if the rest of the system */
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/* Disable the timer and set up the count */
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__raw_writeq(0, IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
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#ifdef CONFIG_SIMULATION
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__raw_writeq((50000 / HZ) - 1,
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IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT)));
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#else
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__raw_writeq((V_SCD_TIMER_FREQ / HZ) - 1,
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IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT)));
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#endif
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/* Set the timer running */
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__raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
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IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
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sb1250_unmask_irq(cpu, irq);
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sb1250_steal_irq(irq);
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/*
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* This interrupt is "special" in that it doesn't use the request_irq
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* way to hook the irq line. The timer interrupt is initialized early
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* enough to make this a major pain, and it's also firing enough to
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* warrant a bit of special case code. sb1250_timer_interrupt is
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* called directly from irq_handler.S when IP[4] is set during an
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* interrupt
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*/
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}
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void sb1250_timer_interrupt(void)
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{
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int cpu = smp_processor_id();
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int irq = K_INT_TIMER_0 + cpu;
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/* ACK interrupt */
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____raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
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IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
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if (cpu == 0) {
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/*
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* CPU 0 handles the global timer interrupt job
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*/
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ll_timer_interrupt(irq);
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}
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else {
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/*
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* other CPUs should just do profiling and process accounting
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*/
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ll_local_timer_interrupt(irq);
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}
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}
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/*
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* The HPT is free running from SB1250_HPT_VALUE down to 0 then starts over
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* again. There's no easy way to set to a specific value so store init value
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* in hpt_offset and subtract each time.
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*
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* Note: Timer isn't full 32bits so shift it into the upper part making
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* it appear to run at a higher frequency.
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*/
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static unsigned int sb1250_hpt_read(void)
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{
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unsigned int count;
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count = G_SCD_TIMER_CNT(__raw_readq(IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CNT))));
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count = (SB1250_HPT_VALUE - count) << SB1250_HPT_SHIFT;
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return count - hpt_offset;
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}
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static void sb1250_hpt_init(unsigned int count)
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{
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hpt_offset = count;
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return;
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}
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