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SubjectFwd: [PATCH v2][for 2.6.28] powerpc/mpic: Add support for MPICs that only support a single CPU destination
Date
Greg,

Can you pick this up for stable-2.6.27.

- k

Begin forwarded message:

> From: Kumar Gala <galak@kernel.crashing.org>
> Date: October 28, 2008 11:01:39 PM CDT
> Cc: linuxppc-dev@ozlabs.org, tglx@linutronix.de, Paul Mackerras <paulus@samba.org
> >, davem@davemloft.net
> Subject: [PATCH v2][for 2.6.28] powerpc/mpic: Add support for MPICs
> that only support a single CPU destination
>
> The Freescale implementation of MPIC only allows a single CPU
> destination
> for non-IPI interrupts. We add a flag to the mpic_init to distinquish
> these variants of MPIC. We pull in the irq_choose_cpu from sparc64 to
> select a single CPU as the destination of the interrupt.
>
> This is to deal with the fact that the default smp affinity was
> changed by commit 18404756765c713a0be4eb1082920c04822ce588.
>
> Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
> ---
>
> Changed requested by Ben to use irq_choose_cpu from sparc64 land.
>
> - k
>
> arch/powerpc/include/asm/mpic.h | 2 +
> arch/powerpc/platforms/85xx/mpc85xx_ds.c | 3 +-
> arch/powerpc/platforms/86xx/pic.c | 3 +-
> arch/powerpc/sysdev/mpic.c | 59 +++++++++++++++++++++
> +++++++--
> 4 files changed, 61 insertions(+), 6 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/mpic.h b/arch/powerpc/include/
> asm/mpic.h
> index 34d9ac4..c2ccca5 100644
> --- a/arch/powerpc/include/asm/mpic.h
> +++ b/arch/powerpc/include/asm/mpic.h
> @@ -355,6 +355,8 @@ struct mpic
> #define MPIC_NO_BIAS 0x00000400
> /* Ignore NIRQS as reported by FRR */
> #define MPIC_BROKEN_FRR_NIRQS 0x00000800
> +/* Destination only supports a single CPU at a time */
> +#define MPIC_SINGLE_DEST_CPU 0x00001000
>
> /* MPIC HW modification ID */
> #define MPIC_REGSET_MASK 0xf0000000
> diff --git a/arch/powerpc/platforms/85xx/mpc85xx_ds.c b/arch/powerpc/
> platforms/85xx/mpc85xx_ds.c
> index 483b65c..613bf8c 100644
> --- a/arch/powerpc/platforms/85xx/mpc85xx_ds.c
> +++ b/arch/powerpc/platforms/85xx/mpc85xx_ds.c
> @@ -78,7 +78,8 @@ void __init mpc85xx_ds_pic_init(void)
>
> mpic = mpic_alloc(np, r.start,
> MPIC_PRIMARY | MPIC_WANTS_RESET |
> - MPIC_BIG_ENDIAN | MPIC_BROKEN_FRR_NIRQS,
> + MPIC_BIG_ENDIAN | MPIC_BROKEN_FRR_NIRQS |
> + MPIC_SINGLE_DEST_CPU,
> 0, 256, " OpenPIC ");
> BUG_ON(mpic == NULL);
> of_node_put(np);
> diff --git a/arch/powerpc/platforms/86xx/pic.c b/arch/powerpc/
> platforms/86xx/pic.c
> index 8881c5d..668275d 100644
> --- a/arch/powerpc/platforms/86xx/pic.c
> +++ b/arch/powerpc/platforms/86xx/pic.c
> @@ -44,7 +44,8 @@ void __init mpc86xx_init_irq(void)
>
> mpic = mpic_alloc(np, res.start,
> MPIC_PRIMARY | MPIC_WANTS_RESET |
> - MPIC_BIG_ENDIAN | MPIC_BROKEN_FRR_NIRQS,
> + MPIC_BIG_ENDIAN | MPIC_BROKEN_FRR_NIRQS |
> + MPIC_SINGLE_DEST_CPU,
> 0, 256, " MPIC ");
> of_node_put(np);
> BUG_ON(mpic == NULL);
> diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c
> index 8e3478c..f6299cc 100644
> --- a/arch/powerpc/sysdev/mpic.c
> +++ b/arch/powerpc/sysdev/mpic.c
> @@ -563,6 +563,51 @@ static void __init mpic_scan_ht_pics(struct
> mpic *mpic)
>
> #endif /* CONFIG_MPIC_U3_HT_IRQS */
>
> +#ifdef CONFIG_SMP
> +static int irq_choose_cpu(unsigned int virt_irq)
> +{
> + cpumask_t mask = irq_desc[virt_irq].affinity;
> + int cpuid;
> +
> + if (cpus_equal(mask, CPU_MASK_ALL)) {
> + static int irq_rover;
> + static DEFINE_SPINLOCK(irq_rover_lock);
> + unsigned long flags;
> +
> + /* Round-robin distribution... */
> + do_round_robin:
> + spin_lock_irqsave(&irq_rover_lock, flags);
> +
> + while (!cpu_online(irq_rover)) {
> + if (++irq_rover >= NR_CPUS)
> + irq_rover = 0;
> + }
> + cpuid = irq_rover;
> + do {
> + if (++irq_rover >= NR_CPUS)
> + irq_rover = 0;
> + } while (!cpu_online(irq_rover));
> +
> + spin_unlock_irqrestore(&irq_rover_lock, flags);
> + } else {
> + cpumask_t tmp;
> +
> + cpus_and(tmp, cpu_online_map, mask);
> +
> + if (cpus_empty(tmp))
> + goto do_round_robin;
> +
> + cpuid = first_cpu(tmp);
> + }
> +
> + return cpuid;
> +}
> +#else
> +static int irq_choose_cpu(unsigned int virt_irq)
> +{
> + return hard_smp_processor_id();
> +}
> +#endif
>
> #define mpic_irq_to_hw(virq) ((unsigned int)irq_map[virq].hwirq)
>
> @@ -777,12 +822,18 @@ void mpic_set_affinity(unsigned int irq,
> cpumask_t cpumask)
> struct mpic *mpic = mpic_from_irq(irq);
> unsigned int src = mpic_irq_to_hw(irq);
>
> - cpumask_t tmp;
> + if (mpic->flags & MPIC_SINGLE_DEST_CPU) {
> + int cpuid = irq_choose_cpu(irq);
>
> - cpus_and(tmp, cpumask, cpu_online_map);
> + mpic_irq_write(src, MPIC_INFO(IRQ_DESTINATION), 1 << cpuid);
> + } else {
> + cpumask_t tmp;
>
> - mpic_irq_write(src, MPIC_INFO(IRQ_DESTINATION),
> - mpic_physmask(cpus_addr(tmp)[0]));
> + cpus_and(tmp, cpumask, cpu_online_map);
> +
> + mpic_irq_write(src, MPIC_INFO(IRQ_DESTINATION),
> + mpic_physmask(cpus_addr(tmp)[0]));
> + }
> }
>
> static unsigned int mpic_type_to_vecpri(struct mpic *mpic, unsigned
> int type)
> --
> 1.5.5.1
>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev



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