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Commit f02cf469 authored by Maciej W. Rozycki's avatar Maciej W. Rozycki Committed by Ralf Baechle
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MIPS: DEC: Implement FPU interrupt counter 



Implement a cheap way to count FPU interrupts for R2k/R3k DECstation
systems.  Do this manually in handcoded assembly, rather than calling
`kstat_incr_irq_this_cpu' that would require setting up a stack frame
and a lot of redirection.  This is not going to be a problem because the
FPU interrupt is local to the CPU and also there is one CPU only anyway.

So at bootstrap determine the address of the correct location within
`struct irq_desc', and then only refer to it directly in the interrupt
handler.

Signed-off-by: default avatarMaciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9713/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 7aecd5ca

arch/mips/dec/int-handler.S

+6 −1
Original line number Diff line number Diff line
@@ -267,8 +267,13 @@ handle_it: 


#ifdef CONFIG_32BIT

fpu:

		j	handle_fpe_int

		lw	t0,fpu_kstat_irq

		nop

		lw	t1,(t0)

		nop

		addu	t1,1

		j	handle_fpe_int

		 sw	t1,(t0)

#endif



spurious:

arch/mips/dec/setup.c

+13 −3
Original line number Diff line number Diff line
@@ -12,13 +12,15 @@ 
#include <linux/init.h>

#include <linux/interrupt.h>

#include <linux/ioport.h>

#include <linux/irq.h>

#include <linux/irqnr.h>

#include <linux/module.h>

#include <linux/param.h>

#include <linux/percpu-defs.h>

#include <linux/sched.h>

#include <linux/spinlock.h>

#include <linux/types.h>

#include <linux/pm.h>

#include <linux/irq.h>



#include <asm/bootinfo.h>

#include <asm/cpu.h>
@@ -98,6 +100,7 @@ int_ptr asic_mask_nr_tbl[DEC_MAX_ASIC_INTS][2] = { 
	{ { .i = ~0 }, { .p = asic_intr_unimplemented } },

};

int cpu_fpu_mask = DEC_CPU_IRQ_MASK(DEC_CPU_INR_FPU);

int *fpu_kstat_irq;



static struct irqaction ioirq = {

	.handler = no_action,
@@ -755,8 +758,15 @@ void __init arch_init_irq(void) 
		dec_interrupt[DEC_IRQ_HALT] = -1;



	/* Register board interrupts: FPU and cascade. */

	if (dec_interrupt[DEC_IRQ_FPU] >= 0)

		setup_irq(dec_interrupt[DEC_IRQ_FPU], &fpuirq);

	if (dec_interrupt[DEC_IRQ_FPU] >= 0) {

		struct irq_desc *desc_fpu;

		int irq_fpu;



		irq_fpu = dec_interrupt[DEC_IRQ_FPU];

		setup_irq(irq_fpu, &fpuirq);

		desc_fpu = irq_to_desc(irq_fpu);

		fpu_kstat_irq = this_cpu_ptr(desc_fpu->kstat_irqs);

	}

	if (dec_interrupt[DEC_IRQ_CASCADE] >= 0)

		setup_irq(dec_interrupt[DEC_IRQ_CASCADE], &ioirq);