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Commit 1ffbc51a authored by Andreas Larsson's avatar Andreas Larsson Committed by David S. Miller
Browse files

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: default avatarAndreas Larsson <andreas@gaisler.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 117a0c5f

arch/sparc/include/asm/leon.h

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/sparc/include/asm/leon_amba.h

+1 −0
Original line number Diff line number Diff line
@@ -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 */

arch/sparc/kernel/leon_kernel.c

+17 −37
Original line number Diff line number Diff line
@@ -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");