Commit e4ee69c8 authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt Committed by Linus Torvalds
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[PATCH] ppc32: Bump PMU interrupt priority 



The Power Management Unit on PowerMacs is very sensitive to timeouts during
async message exchanges.  It uses rather crude protocol based on a shift
register with an interrupt and is almost continuously exchanging messages with
the host CPU on laptops.

This patch adds a routine to the open_pic driver to be able to select a PMU
driver so that it bumps it's interrupt priority to above the normal level.

This will allow PMU interrupts to occur while another interrupt is pending,
and thus reduce the risk of machine beeing abruptly shutdown by the PMU due to
a timeout in PMU communication caused by excessive interrupt latency.  The
problem is very rare, and usually just doesn't happen, but it is still useful
to make things even more robust.

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent bb165746

arch/ppc/syslib/open_pic.c

+19 −7
Original line number Diff line number Diff line
@@ -370,8 +370,9 @@ void __init openpic_init(int offset) 
	/* Initialize IPI interrupts */

	if ( ppc_md.progress ) ppc_md.progress("openpic: ipi",0x3bb);

	for (i = 0; i < OPENPIC_NUM_IPI; i++) {

		/* Disabled, Priority 10..13 */

		openpic_initipi(i, 10+i, OPENPIC_VEC_IPI+i+offset);

		/* Disabled, increased priorities 10..13 */

		openpic_initipi(i, OPENPIC_PRIORITY_IPI_BASE+i,

				OPENPIC_VEC_IPI+i+offset);

		/* IPIs are per-CPU */

		irq_desc[OPENPIC_VEC_IPI+i+offset].status |= IRQ_PER_CPU;

		irq_desc[OPENPIC_VEC_IPI+i+offset].handler = &open_pic_ipi;
@@ -399,8 +400,9 @@ void __init openpic_init(int offset) 
		if (sense & IRQ_SENSE_MASK)

			irq_desc[i+offset].status = IRQ_LEVEL;



		/* Enabled, Priority 8 */

		openpic_initirq(i, 8, i+offset, (sense & IRQ_POLARITY_MASK),

		/* Enabled, Default priority */

		openpic_initirq(i, OPENPIC_PRIORITY_DEFAULT, i+offset,

				(sense & IRQ_POLARITY_MASK),

				(sense & IRQ_SENSE_MASK));

		/* Processor 0 */

		openpic_mapirq(i, CPU_MASK_CPU0, CPU_MASK_NONE);
@@ -655,6 +657,18 @@ static void __init openpic_maptimer(u_int timer, cpumask_t cpumask) 
		      cpus_addr(phys)[0]);

}



/*

 * Change the priority of an interrupt

 */

void __init

openpic_set_irq_priority(u_int irq, u_int pri)

{

	check_arg_irq(irq);

	openpic_safe_writefield(&ISR[irq - open_pic_irq_offset]->Vector_Priority,

				OPENPIC_PRIORITY_MASK,

				pri << OPENPIC_PRIORITY_SHIFT);

}



/*

 * Initalize the interrupt source which will generate an NMI.

 * This raises the interrupt's priority from 8 to 9.
@@ -665,9 +679,7 @@ void __init 
openpic_init_nmi_irq(u_int irq)

{

	check_arg_irq(irq);

	openpic_safe_writefield(&ISR[irq - open_pic_irq_offset]->Vector_Priority,

				OPENPIC_PRIORITY_MASK,

				9 << OPENPIC_PRIORITY_SHIFT);

	openpic_set_irq_priority(irq, OPENPIC_PRIORITY_NMI);

}



/*

drivers/macintosh/via-pmu.c

+10 −0
Original line number Diff line number Diff line
@@ -63,6 +63,10 @@ 
#include <asm/backlight.h>

#endif



#ifdef CONFIG_PPC32

#include <asm/open_pic.h>

#endif



/* Some compile options */

#undef SUSPEND_USES_PMU

#define DEBUG_SLEEP
@@ -407,6 +411,12 @@ static int __init via_pmu_start(void) 
	batt_req.complete = 1;

#endif



#ifdef CONFIG_PPC32

	if (pmu_kind == PMU_KEYLARGO_BASED)

		openpic_set_irq_priority(vias->intrs[0].line,

					 OPENPIC_PRIORITY_DEFAULT + 1);

#endif



	if (request_irq(vias->intrs[0].line, via_pmu_interrupt, 0, "VIA-PMU",

			(void *)0)) {

		printk(KERN_ERR "VIA-PMU: can't get irq %d\n",

include/asm-ppc/open_pic.h

+6 −0
Original line number Diff line number Diff line
@@ -25,6 +25,11 @@ 
#define OPENPIC_VEC_IPI		118	/* and up */

#define OPENPIC_VEC_SPURIOUS	255



/* Priorities */

#define OPENPIC_PRIORITY_IPI_BASE	10

#define OPENPIC_PRIORITY_DEFAULT	4

#define OPENPIC_PRIORITY_NMI		9



/* OpenPIC IRQ controller structure */

extern struct hw_interrupt_type open_pic;
@@ -42,6 +47,7 @@ extern int epic_serial_mode; 
extern void openpic_set_sources(int first_irq, int num_irqs, void __iomem *isr);

extern void openpic_init(int linux_irq_offset);

extern void openpic_init_nmi_irq(u_int irq);

extern void openpic_set_irq_priority(u_int irq, u_int pri);

extern void openpic_hookup_cascade(u_int irq, char *name,

				   int (*cascade_fn)(struct pt_regs *));

extern u_int openpic_irq(void);

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