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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: Stephen Rothwell <sfr@canb.auug.org.au>
This commit is contained in:
Stephen Rothwell 2006-04-04 14:49:48 +10:00
parent 6246b6128b
commit 7d01c88085
3 changed files with 36 additions and 14 deletions
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36
arch/powerpc/kernel/irq.c
View File

@ -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);

7
arch/powerpc/platforms/iseries/setup.c
View File

@ -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;
}

7
include/asm-powerpc/irq.h
View File

@ -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.
*/