Re: Fwd: [PATCH v2][for 2.6.28] powerpc/mpic: Add support forMPICs that only support a single CPU destination
From: Greg KH
Date: Tue Nov 11 2008 - 16:35:10 EST
On Wed, Nov 05, 2008 at 05:38:48PM -0600, Kumar Gala wrote:
> Greg,
>
> Can you pick this up for stable-2.6.27.
I don't see this in Linus's tree right now.
Am I missing it? Or do you know what the git commit id is?
thanks,
greg k-h
>> From: Kumar Gala <galak@xxxxxxxxxxxxxxxxxxx>
>> Date: October 28, 2008 11:01:39 PM CDT
>> Cc: linuxppc-dev@xxxxxxxxxx, tglx@xxxxxxxxxxxxx, Paul Mackerras
>> <paulus@xxxxxxxxx>, davem@xxxxxxxxxxxxx
>> 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@xxxxxxxxxxxxxxxxxxx>
>> ---
>>
>> 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
>>
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