On Tue, Apr 19, 2011 at 06:07:19PM +0200, Daniel Hellstrom wrote:
> A simple implementation of CPU affinity, the first CPU in
> the affinity CPU mask always takes the IRQ.
>
> Signed-off-by: Daniel Hellstrom <daniel@xxxxxxxxxxx>
> ---
> arch/sparc/kernel/leon_kernel.c | 66 +++++++++++++++++++++++++++++++++------
> 1 files changed, 56 insertions(+), 10 deletions(-)
>
> diff --git a/arch/sparc/kernel/leon_kernel.c b/arch/sparc/kernel/leon_kernel.c
> index 26acc75..e12f4e8 100644
> --- a/arch/sparc/kernel/leon_kernel.c
> +++ b/arch/sparc/kernel/leon_kernel.c
> @@ -100,25 +100,68 @@ static inline unsigned long get_irqmask(unsigned int irq)
> return mask;
> }
>
> +#ifdef CONFIG_SMP
> +static int irq_choose_cpu(const struct cpumask *affinity)
> +{
> + cpumask_t mask;
> +
> + cpus_and(mask, cpu_online_map, *affinity);
> + if (cpus_equal(mask, cpu_online_map) || cpus_empty(mask))
> + return leon3_boot_cpu;
> + else
> + return first_cpu(mask);
> +}
> +
> +int leon_set_affinity(struct irq_data *data, const struct cpumask *dest,
> + bool force)
> +{
> + unsigned long mask, oldmask, flags;
> + int oldcpu, newcpu;
> +
> + mask = (unsigned long)data->chip_data;
> + oldcpu = irq_choose_cpu(data->affinity);
> + newcpu = irq_choose_cpu(dest);
> +
> + if (oldcpu == newcpu)
> + goto out;
> +
> + /* unmask on old CPU first before enabling on the selected CPU */
> + spin_lock_irqsave(&leon_irq_lock, flags);
> + oldmask = LEON3_BYPASS_LOAD_PA(LEON_IMASK(oldcpu));
> + LEON3_BYPASS_STORE_PA(LEON_IMASK(oldcpu), (oldmask & ~mask));
> + oldmask = LEON3_BYPASS_LOAD_PA(LEON_IMASK(newcpu));
> + LEON3_BYPASS_STORE_PA(LEON_IMASK(newcpu), (oldmask | mask));
> + spin_unlock_irqrestore(&leon_irq_lock, flags);
> +out:
> + return IRQ_SET_MASK_OK;
> +}
> +#else
> +#define irq_choose_cpu(affinity) leon3_boot_cpu
> +#endif
We could always define the leon_set_affinity() function
to avoid ifdeffery in irq_chip definition.
The expense is that we define this function in both the
UP and SMP case - it is NOT called by the generic irq
layer in the UP case.
Sam
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