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sparc32, leon: Remove separate "ticker" timer for SMP

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This reduces the need from two timers to one timer.

Moreover, without this patch, when the "ticker" timer triggers timer_cs_read via
tick_periodic it reads the value of the usual timer it can get an wrapped timer
value without timer_cs_internal_counter having been updated leading to the clock
going backwards. This effectively hangs one cpu that gets stuck in
update_wall_time with an offset slightly smaller than 0xffffffffffffffff.

Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Andreas Larsson 2013-06-10 08:53:28 +02:00 committed by David S. Miller
parent 117a0c5fc9
commit 1ffbc51a0d
3 changed files with 26 additions and 45 deletions
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2
arch/sparc/include/asm/leon.h
View File

@ -135,7 +135,7 @@ static inline int sparc_leon3_cpuid(void)
#ifdef CONFIG_SMP
# define LEON3_IRQ_IPI_DEFAULT 13
# define LEON3_IRQ_TICKER (leon3_ticker_irq)
# define LEON3_IRQ_TICKER (leon3_gptimer_irq)
# define LEON3_IRQ_CROSS_CALL 15
#endif

1
arch/sparc/include/asm/leon_amba.h
View File

@ -47,6 +47,7 @@ struct amba_prom_registers {
#define LEON3_GPTIMER_LD 4
#define LEON3_GPTIMER_IRQEN 8
#define LEON3_GPTIMER_SEPIRQ 8
#define LEON3_GPTIMER_TIMERS 0x7
#define LEON23_REG_TIMER_CONTROL_EN 0x00000001 /* 1 = enable counting */
/* 0 = hold scalar and counter */

68
arch/sparc/kernel/leon_kernel.c
View File

@ -38,7 +38,6 @@ static DEFINE_SPINLOCK(leon_irq_lock);
unsigned long leon3_gptimer_irq; /* interrupt controller irq number */
unsigned long leon3_gptimer_idx; /* Timer Index (0..6) within Timer Core */
int leon3_ticker_irq; /* Timer ticker IRQ */
unsigned int sparc_leon_eirq;
#define LEON_IMASK(cpu) (&leon3_irqctrl_regs->mask[cpu])
#define LEON_IACK (&leon3_irqctrl_regs->iclear)
@ -278,6 +277,9 @@ irqreturn_t leon_percpu_timer_ce_interrupt(int irq, void *unused)
leon_clear_profile_irq(cpu);
if (cpu == boot_cpu_id)
timer_interrupt(irq, NULL);
ce = &per_cpu(sparc32_clockevent, cpu);
irq_enter();
@ -299,6 +301,7 @@ void __init leon_init_timers(void)
int icsel;
int ampopts;
int err;
u32 config;
sparc_config.get_cycles_offset = leon_cycles_offset;
sparc_config.cs_period = 1000000 / HZ;
@ -377,23 +380,6 @@ void __init leon_init_timers(void)
LEON3_BYPASS_STORE_PA(
&leon3_gptimer_regs->e[leon3_gptimer_idx].ctrl, 0);
#ifdef CONFIG_SMP
leon3_ticker_irq = leon3_gptimer_irq + 1 + leon3_gptimer_idx;
if (!(LEON3_BYPASS_LOAD_PA(&leon3_gptimer_regs->config) &
(1<<LEON3_GPTIMER_SEPIRQ))) {
printk(KERN_ERR "timer not configured with separate irqs\n");
BUG();
}
LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx+1].val,
0);
LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx+1].rld,
(((1000000/HZ) - 1)));
LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx+1].ctrl,
0);
#endif
/*
* The IRQ controller may (if implemented) consist of multiple
* IRQ controllers, each mapped on a 4Kb boundary.
@ -416,13 +402,6 @@ void __init leon_init_timers(void)
if (eirq != 0)
leon_eirq_setup(eirq);
irq = _leon_build_device_irq(NULL, leon3_gptimer_irq+leon3_gptimer_idx);
err = request_irq(irq, timer_interrupt, IRQF_TIMER, "timer", NULL);
if (err) {
printk(KERN_ERR "unable to attach timer IRQ%d\n", irq);
prom_halt();
}
#ifdef CONFIG_SMP
{
unsigned long flags;
@ -439,30 +418,31 @@ void __init leon_init_timers(void)
}
#endif
config = LEON3_BYPASS_LOAD_PA(&leon3_gptimer_regs->config);
if (config & (1 << LEON3_GPTIMER_SEPIRQ))
leon3_gptimer_irq += leon3_gptimer_idx;
else if ((config & LEON3_GPTIMER_TIMERS) > 1)
pr_warn("GPTIMER uses shared irqs, using other timers of the same core will fail.\n");
#ifdef CONFIG_SMP
/* Install per-cpu IRQ handler for broadcasted ticker */
irq = leon_build_device_irq(leon3_gptimer_irq, handle_percpu_irq,
"per-cpu", 0);
err = request_irq(irq, leon_percpu_timer_ce_interrupt,
IRQF_PERCPU | IRQF_TIMER, "timer", NULL);
#else
irq = _leon_build_device_irq(NULL, leon3_gptimer_irq);
err = request_irq(irq, timer_interrupt, IRQF_TIMER, "timer", NULL);
#endif
if (err) {
pr_err("Unable to attach timer IRQ%d\n", irq);
prom_halt();
}
LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].ctrl,
LEON3_GPTIMER_EN |
LEON3_GPTIMER_RL |
LEON3_GPTIMER_LD |
LEON3_GPTIMER_IRQEN);
#ifdef CONFIG_SMP
/* Install per-cpu IRQ handler for broadcasted ticker */
irq = leon_build_device_irq(leon3_ticker_irq, handle_percpu_irq,
"per-cpu", 0);
err = request_irq(irq, leon_percpu_timer_ce_interrupt,
IRQF_PERCPU | IRQF_TIMER, "ticker",
NULL);
if (err) {
printk(KERN_ERR "unable to attach ticker IRQ%d\n", irq);
prom_halt();
}
LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx+1].ctrl,
LEON3_GPTIMER_EN |
LEON3_GPTIMER_RL |
LEON3_GPTIMER_LD |
LEON3_GPTIMER_IRQEN);
#endif
return;
bad:
printk(KERN_ERR "No Timer/irqctrl found\n");