3 patches against linuxppc_dev-2.4.18-pre7

Hello

The attached patch fixes the following issues:

- arch/ppc/kernel/ppc4xx_pic.c
fixed constant in ppc405_pic_get_irq() (should be NR_AIC_IRQS as in ppc403_pic_get_irq())

Quoted 8 lines · David Müller (ELSOFT AG)

Hello

The attached patch fixes the following issues:

- arch/ppc/kernel/ppc4xx_pic.c
fixed constant in ppc405_pic_get_irq() (should be NR_AIC_IRQS as in ppc403_pic_get_irq())

David,

include/asm-ppc/irq.h
NR_IRQS = (NR_AIC_IRQS + NR_BOARD_IRQS) and was defined to allow cascading UIC's.
NR_BOARD_IRQS is defined in some of the board files and its default is in include/asm-ppc/ibm4xx.h

So i don't see the need to patch that file but the others look fine.

Hi

Quoted 13 lines · Armin Kuster

Quoted 8 lines · David Müller (ELSOFT AG)

Hello

The attached patch fixes the following issues:

- arch/ppc/kernel/ppc4xx_pic.c
fixed constant in ppc405_pic_get_irq() (should be NR_AIC_IRQS as in ppc403_pic_get_irq())

David,

Quoted 9 lines

include/asm-ppc/irq.h
NR_IRQS = (NR_AIC_IRQS + NR_BOARD_IRQS) and was defined to allow cascading UIC's.
NR_BOARD_IRQS is defined in some of the board files and its default is in include/asm-ppc/ibm4xx.h

So i don't see the need to patch that file but the others look fine.

Exactly, NR_IRQS is the the total number of irqs possible in the system as this number of irqs is reserved in the irq_desc table.

For example, we have a system with a PPC405GP and an additional PC like 8259 PIC pair, we have NR_AIC_IRQS (32) + NR_BOARD_IRQS (16) = NR_IRQS (48).

In ppc405_pic_get_irq() the following code is executed:

        irq = 32 - ffs(bits);

        if (irq == NR_IRQS)
                irq = -1;

        return(irq);

with NR_IRQS equal 48 the condition is never true !

This results in an endless while-loop in do_IRQ() in arch/ppc/kernel/irq.c

Either this or my understanding how things are working is totally wrong. ;-) Additionally, i don't see me why ppc403_pic_get_irq() is using NC_AIC_IRQS while ppc405_pic_get_irq() is using NR_IRQS. Shouldn't they be "symmetric".

Dave

Quoted 6 lines

In ppc405_pic_get_irq() the following code is executed:

        irq = 32 - ffs(bits);

Quoted 7 lines

        if (irq == NR_IRQS)
                irq = -1;

        return(irq);

with NR_IRQS equal 48 the condition is never true !

You might check the actual code generated for ffs() and verify it works -- I ended up recoding this routine because ffs() wasn't working correctly ... [ I forget the particulars, but the code generated and behavior were not correct ];