sparc32,leon: implement genirq CPU affinity

A simple implementation of CPU affinity, the first CPU in
the affinity CPU mask always takes the IRQ.

Signed-off-by: Daniel Hellstrom <daniel@gaisler.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 54 insertions, 10 deletions

diff --git a/arch/sparc/kernel/leon_kernel.c b/arch/sparc/kernel/leon_kernel.c
index d8fafeacb496..ab1458454422 100644
--- a/arch/sparc/kernel/leon_kernel.c
+++ b/arch/sparc/kernel/leon_kernel.c
@@ -99,25 +99,68 @@ 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 0;
+        else
+                return first_cpu(mask);
+}
+#else
+#define irq_choose_cpu(affinity) 0
+#endif
+
+static 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;
+}
+
 static void leon_unmask_irq(struct irq_data *data)
 {
         unsigned long mask, oldmask, flags;
+        int cpu;
 
         mask = (unsigned long)data->chip_data;
+        cpu = irq_choose_cpu(data->affinity);
         spin_lock_irqsave(&leon_irq_lock, flags);
-        oldmask = LEON3_BYPASS_LOAD_PA(LEON_IMASK(0));
-        LEON3_BYPASS_STORE_PA(LEON_IMASK(0), (oldmask | mask));
+        oldmask = LEON3_BYPASS_LOAD_PA(LEON_IMASK(cpu));
+        LEON3_BYPASS_STORE_PA(LEON_IMASK(cpu), (oldmask | mask));
         spin_unlock_irqrestore(&leon_irq_lock, flags);
 }
 
 static void leon_mask_irq(struct irq_data *data)
 {
         unsigned long mask, oldmask, flags;
+        int cpu;
 
         mask = (unsigned long)data->chip_data;
+        cpu = irq_choose_cpu(data->affinity);
         spin_lock_irqsave(&leon_irq_lock, flags);
-        oldmask = LEON3_BYPASS_LOAD_PA(LEON_IMASK(0));
-        LEON3_BYPASS_STORE_PA(LEON_IMASK(0), (oldmask & ~mask));
+        oldmask = LEON3_BYPASS_LOAD_PA(LEON_IMASK(cpu));
+        LEON3_BYPASS_STORE_PA(LEON_IMASK(cpu), (oldmask & ~mask));
         spin_unlock_irqrestore(&leon_irq_lock, flags);
 }
 
@@ -144,12 +187,13 @@ static void leon_eoi_irq(struct irq_data *data)
 }
 
 static struct irq_chip leon_irq = {
-        .name           = "leon",
-        .irq_startup    = leon_startup_irq,
-        .irq_shutdown   = leon_shutdown_irq,
-        .irq_mask       = leon_mask_irq,
-        .irq_unmask     = leon_unmask_irq,
-        .irq_eoi        = leon_eoi_irq,
+        .name                   = "leon",
+        .irq_startup            = leon_startup_irq,
+        .irq_shutdown           = leon_shutdown_irq,
+        .irq_mask               = leon_mask_irq,
+        .irq_unmask             = leon_unmask_irq,
+        .irq_eoi                = leon_eoi_irq,
+        .irq_set_affinity       = leon_set_affinity,
 };
 
 /*