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authorAndreas Larsson <andreas@gaisler.com>2013-06-10 06:53:28 (GMT)
committerDavid S. Miller <davem@davemloft.net>2013-06-19 09:10:29 (GMT)
commit1ffbc51a0d00e52983c70aa7c8dbc7b621d6287d (patch)
tree3b5e0a1a91a2dfde1b93d2d3295d1170ffe2bae3
parent117a0c5fc9c2d06045bd217385b2b39ea426b5a6 (diff)
downloadlinux-1ffbc51a0d00e52983c70aa7c8dbc7b621d6287d.tar.xz
sparc32, leon: Remove separate "ticker" timer for SMP
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>
-rw-r--r--arch/sparc/include/asm/leon.h2
-rw-r--r--arch/sparc/include/asm/leon_amba.h1
-rw-r--r--arch/sparc/kernel/leon_kernel.c54
3 files changed, 19 insertions, 38 deletions
diff --git a/arch/sparc/include/asm/leon.h b/arch/sparc/include/asm/leon.h
index 15a7169..b836e92 100644
--- a/arch/sparc/include/asm/leon.h
+++ b/arch/sparc/include/asm/leon.h
@@ -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
diff --git a/arch/sparc/include/asm/leon_amba.h b/arch/sparc/include/asm/leon_amba.h
index f3034ed..24ec48c 100644
--- a/arch/sparc/include/asm/leon_amba.h
+++ b/arch/sparc/include/asm/leon_amba.h
@@ -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 */
diff --git a/arch/sparc/kernel/leon_kernel.c b/arch/sparc/kernel/leon_kernel.c
index 7c0231d..b7c6897 100644
--- a/arch/sparc/kernel/leon_kernel.c
+++ b/arch/sparc/kernel/leon_kernel.c
@@ -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
- LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].ctrl,
- LEON3_GPTIMER_EN |
- LEON3_GPTIMER_RL |
- LEON3_GPTIMER_LD |
- LEON3_GPTIMER_IRQEN);
+ 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_ticker_irq, handle_percpu_irq,
+ 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, "ticker",
- NULL);
+ 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) {
- printk(KERN_ERR "unable to attach ticker IRQ%d\n", irq);
+ pr_err("Unable to attach timer IRQ%d\n", irq);
prom_halt();
}
-
- LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx+1].ctrl,
+ LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].ctrl,
LEON3_GPTIMER_EN |
LEON3_GPTIMER_RL |
LEON3_GPTIMER_LD |
LEON3_GPTIMER_IRQEN);
-#endif
return;
bad:
printk(KERN_ERR "No Timer/irqctrl found\n");