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Commit 7d01c880 authored by Stephen Rothwell's avatar Stephen Rothwell
Browse files

powerpc: iSeries has only 256 IRQs 



The iSeries Hypervisor only allows us to specify IRQ numbers up to 255 (it
has a u8 field to pass it in).  This patch allows platforms to specify a
maximum to the virtual IRQ numbers we will use and has iSeries set that
to 255.  If not set, the maximum is NR_IRQS - 1 (as before).

Signed-off-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
parent 6246b612

arch/powerpc/kernel/irq.c

+22 −14
Original line number Diff line number Diff line
@@ -272,18 +272,26 @@ unsigned int virt_irq_to_real_map[NR_IRQS]; 
 * Don't use virtual irqs 0, 1, 2 for devices.

 * The pcnet32 driver considers interrupt numbers < 2 to be invalid,

 * and 2 is the XICS IPI interrupt.

 * We limit virtual irqs to 17 less than NR_IRQS so that when we

 * offset them by 16 (to reserve the first 16 for ISA interrupts)

 * we don't end up with an interrupt number >= NR_IRQS.

 * We limit virtual irqs to __irq_offet_value less than virt_irq_max so

 * that when we offset them we don't end up with an interrupt

 * number >= virt_irq_max.

 */

#define MIN_VIRT_IRQ	3

#define MAX_VIRT_IRQ	(NR_IRQS - NUM_ISA_INTERRUPTS - 1)

#define NR_VIRT_IRQS	(MAX_VIRT_IRQ - MIN_VIRT_IRQ + 1)



unsigned int virt_irq_max;

static unsigned int max_virt_irq;

static unsigned int nr_virt_irqs;



void

virt_irq_init(void)

{

	int i;



	if ((virt_irq_max == 0) || (virt_irq_max > (NR_IRQS - 1)))

		virt_irq_max = NR_IRQS - 1;

	max_virt_irq = virt_irq_max - __irq_offset_value;

	nr_virt_irqs = max_virt_irq - MIN_VIRT_IRQ + 1;



	for (i = 0; i < NR_IRQS; i++)

		virt_irq_to_real_map[i] = UNDEFINED_IRQ;

}
@@ -308,17 +316,17 @@ int virt_irq_create_mapping(unsigned int real_irq) 
		return real_irq;

	}



	/* map to a number between MIN_VIRT_IRQ and MAX_VIRT_IRQ */

	/* map to a number between MIN_VIRT_IRQ and max_virt_irq */

	virq = real_irq;

	if (virq > MAX_VIRT_IRQ)

		virq = (virq % NR_VIRT_IRQS) + MIN_VIRT_IRQ;

	if (virq > max_virt_irq)

		virq = (virq % nr_virt_irqs) + MIN_VIRT_IRQ;



	/* search for this number or a free slot */

	first_virq = virq;

	while (virt_irq_to_real_map[virq] != UNDEFINED_IRQ) {

		if (virt_irq_to_real_map[virq] == real_irq)

			return virq;

		if (++virq > MAX_VIRT_IRQ)

		if (++virq > max_virt_irq)

			virq = MIN_VIRT_IRQ;

		if (virq == first_virq)

			goto nospace;	/* oops, no free slots */
@@ -330,8 +338,8 @@ int virt_irq_create_mapping(unsigned int real_irq) 
 nospace:

	if (!warned) {

		printk(KERN_CRIT "Interrupt table is full\n");

		printk(KERN_CRIT "Increase NR_IRQS (currently %d) "

		       "in your kernel sources and rebuild.\n", NR_IRQS);

		printk(KERN_CRIT "Increase virt_irq_max (currently %d) "

		       "in your kernel sources and rebuild.\n", virt_irq_max);

		warned = 1;

	}

	return NO_IRQ;
@@ -349,8 +357,8 @@ unsigned int real_irq_to_virt_slowpath(unsigned int real_irq) 


	virq = real_irq;



	if (virq > MAX_VIRT_IRQ)

		virq = (virq % NR_VIRT_IRQS) + MIN_VIRT_IRQ;

	if (virq > max_virt_irq)

		virq = (virq % nr_virt_irqs) + MIN_VIRT_IRQ;



	first_virq = virq;
@@ -360,7 +368,7 @@ unsigned int real_irq_to_virt_slowpath(unsigned int real_irq) 


		virq++;



		if (virq >= MAX_VIRT_IRQ)

		if (virq >= max_virt_irq)

			virq = 0;



	} while (first_virq != virq);

arch/powerpc/platforms/iseries/setup.c

+7 −0
Original line number Diff line number Diff line
@@ -54,6 +54,7 @@ 
#include <asm/iseries/hv_lp_event.h>

#include <asm/iseries/lpar_map.h>

#include <asm/udbg.h>

#include <asm/irq.h>



#include "naca.h"

#include "setup.h"
@@ -684,6 +685,12 @@ static int __init iseries_probe(void) 
	powerpc_firmware_features |= FW_FEATURE_ISERIES;

	powerpc_firmware_features |= FW_FEATURE_LPAR;



	/*

	 * The Hypervisor only allows us up to 256 interrupt

	 * sources (the irq number is passed in a u8).

	 */

	virt_irq_max = 255;



	return 1;

}

include/asm-powerpc/irq.h

+7 −0
Original line number Diff line number Diff line
@@ -54,6 +54,13 @@ 
 */

extern unsigned int virt_irq_to_real_map[NR_IRQS];



/* The maximum virtual IRQ number that we support.  This

 * can be set by the platform and will be reduced by the

 * value of __irq_offset_value.  It defaults to and is

 * capped by (NR_IRQS - 1).

 */

extern unsigned int virt_irq_max;



/* Create a mapping for a real_irq if it doesn't already exist.

 * Return the virtual irq as a convenience.

 */