8dfa741f14
We have no guarantee by the generic time code that the timer is stopped when the ->next_event method is called. Modifying the Timer Initial Count register while the timer is enabled has UNPREDICTABLE effect according to the BCM1250/BCM1125/BCM1125H User Manual. So stop the timer before reprogramming. This is a paranoia fix; no ill effects have been observed previously. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
153 lines
4.4 KiB
C
153 lines
4.4 KiB
C
/*
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* Copyright (C) 2000,2001,2004 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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#include <linux/clockchips.h>
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#include <linux/interrupt.h>
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#include <linux/percpu.h>
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#include <asm/addrspace.h>
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#include <asm/io.h>
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#include <asm/time.h>
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#include <asm/sibyte/bcm1480_regs.h>
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#include <asm/sibyte/sb1250_regs.h>
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#include <asm/sibyte/bcm1480_int.h>
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#include <asm/sibyte/bcm1480_scd.h>
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#include <asm/sibyte/sb1250.h>
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#define IMR_IP2_VAL K_BCM1480_INT_MAP_I0
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#define IMR_IP3_VAL K_BCM1480_INT_MAP_I1
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#define IMR_IP4_VAL K_BCM1480_INT_MAP_I2
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/*
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* The general purpose timer ticks at 1MHz independent if
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* the rest of the system
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*/
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static void sibyte_set_mode(enum clock_event_mode mode,
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struct clock_event_device *evt)
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{
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unsigned int cpu = smp_processor_id();
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void __iomem *cfg, *init;
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cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
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init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));
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switch (mode) {
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case CLOCK_EVT_MODE_PERIODIC:
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__raw_writeq(0, cfg);
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__raw_writeq((V_SCD_TIMER_FREQ / HZ) - 1, init);
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__raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
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cfg);
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break;
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case CLOCK_EVT_MODE_ONESHOT:
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/* Stop the timer until we actually program a shot */
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case CLOCK_EVT_MODE_SHUTDOWN:
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__raw_writeq(0, cfg);
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break;
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case CLOCK_EVT_MODE_UNUSED: /* shuddup gcc */
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case CLOCK_EVT_MODE_RESUME:
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;
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}
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}
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static int sibyte_next_event(unsigned long delta, struct clock_event_device *cd)
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{
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unsigned int cpu = smp_processor_id();
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void __iomem *cfg, *init;
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cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
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init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));
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__raw_writeq(0, cfg);
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__raw_writeq(delta - 1, init);
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__raw_writeq(M_SCD_TIMER_ENABLE, cfg);
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return 0;
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}
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static irqreturn_t sibyte_counter_handler(int irq, void *dev_id)
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{
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unsigned int cpu = smp_processor_id();
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struct clock_event_device *cd = dev_id;
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void __iomem *cfg;
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unsigned long tmode;
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if (cd->mode == CLOCK_EVT_MODE_PERIODIC)
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tmode = M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS;
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else
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tmode = 0;
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/* ACK interrupt */
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cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
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____raw_writeq(tmode, cfg);
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cd->event_handler(cd);
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return IRQ_HANDLED;
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}
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static DEFINE_PER_CPU(struct clock_event_device, sibyte_hpt_clockevent);
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static DEFINE_PER_CPU(struct irqaction, sibyte_hpt_irqaction);
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static DEFINE_PER_CPU(char [18], sibyte_hpt_name);
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void __cpuinit sb1480_clockevent_init(void)
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{
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unsigned int cpu = smp_processor_id();
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unsigned int irq = K_BCM1480_INT_TIMER_0 + cpu;
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struct irqaction *action = &per_cpu(sibyte_hpt_irqaction, cpu);
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struct clock_event_device *cd = &per_cpu(sibyte_hpt_clockevent, cpu);
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unsigned char *name = per_cpu(sibyte_hpt_name, cpu);
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BUG_ON(cpu > 3); /* Only have 4 general purpose timers */
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sprintf(name, "bcm1480-counter-%d", cpu);
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cd->name = name;
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cd->features = CLOCK_EVT_FEAT_PERIODIC |
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CLOCK_EVT_FEAT_ONESHOT;
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clockevent_set_clock(cd, V_SCD_TIMER_FREQ);
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cd->max_delta_ns = clockevent_delta2ns(0x7fffff, cd);
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cd->min_delta_ns = clockevent_delta2ns(2, cd);
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cd->rating = 200;
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cd->irq = irq;
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cd->cpumask = cpumask_of_cpu(cpu);
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cd->set_next_event = sibyte_next_event;
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cd->set_mode = sibyte_set_mode;
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clockevents_register_device(cd);
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bcm1480_mask_irq(cpu, irq);
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/*
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* Map the timer interrupt to IP[4] of this cpu
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*/
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__raw_writeq(IMR_IP4_VAL,
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IOADDR(A_BCM1480_IMR_REGISTER(cpu,
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R_BCM1480_IMR_INTERRUPT_MAP_BASE_H) + (irq << 3)));
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bcm1480_unmask_irq(cpu, irq);
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action->handler = sibyte_counter_handler;
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action->flags = IRQF_DISABLED | IRQF_PERCPU;
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action->mask = cpumask_of_cpu(cpu);
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action->name = name;
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action->dev_id = cd;
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irq_set_affinity(irq, cpumask_of_cpu(cpu));
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setup_irq(irq, action);
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}
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