Sam Ravnborg wrote:
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.
Yes, that is what sparc64 does.
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.
Yes, it would increase the footprint to remove one ifdef. I could add a
"#define leon_set_affinity NULL" in the already present ifdef above to
avoid the extra ifdef in chip declaration?
Thanks,
Daniel
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