MIPS: Loongson-3: support irq_set_affinity() in i8259 chip

With this patch we can set irq affinity via procfs, so as to improve
network performance.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J . Hill <Steven.Hill@cavium.com>
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16590/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/loongson64/loongson-3/irq.c b/arch/mips/loongson64/loongson-3/irq.c
index 2e6e205ed9b9e9930b6d222079f59eeb5b5d7d4a..7202e52cd0469251d198c50c97d081c4270ca341 100644 (file)
--- a/arch/mips/loongson64/loongson-3/irq.c
+++ b/arch/mips/loongson64/loongson-3/irq.c
@@ -10,32 +10,68 @@
 #include "smp.h"
 
 extern void loongson3_send_irq_by_ipi(int cpu, int irqs);
+
+unsigned int irq_cpu[16] = {[0 ... 15] = -1};
 unsigned int ht_irq[] = {0, 1, 3, 4, 5, 6, 7, 8, 12, 14, 15};
 unsigned int local_irq = 1<<0 | 1<<1 | 1<<2 | 1<<7 | 1<<8 | 1<<12;
 
+int plat_set_irq_affinity(struct irq_data *d, const struct cpumask *affinity,
+                         bool force)
+{
+       unsigned int cpu;
+       struct cpumask new_affinity;
+
+       /* I/O devices are connected on package-0 */
+       cpumask_copy(&new_affinity, affinity);
+       for_each_cpu(cpu, affinity)
+               if (cpu_data[cpu].package > 0)
+                       cpumask_clear_cpu(cpu, &new_affinity);
+
+       if (cpumask_empty(&new_affinity))
+               return -EINVAL;
+
+       cpumask_copy(d->common->affinity, &new_affinity);
+
+       return IRQ_SET_MASK_OK_NOCOPY;
+}
+
 static void ht_irqdispatch(void)
 {
-       unsigned int i, irq, irq0, irq1;
-       static unsigned int dest_cpu = 0;
+       unsigned int i, irq;
+       struct irq_data *irqd;
+       struct cpumask affinity;
 
        irq = LOONGSON_HT1_INT_VECTOR(0);
        LOONGSON_HT1_INT_VECTOR(0) = irq; /* Acknowledge the IRQs */
 
-       irq0 = irq & local_irq;  /* handled by local core */
-       irq1 = irq & ~local_irq; /* balanced by other cores */
+       for (i = 0; i < ARRAY_SIZE(ht_irq); i++) {
+               if (!(irq & (0x1 << ht_irq[i])))
+                       continue;
 
-       if (dest_cpu == 0 || !cpu_online(dest_cpu))
-               irq0 |= irq1;
-       else
-               loongson3_send_irq_by_ipi(dest_cpu, irq1);
+               /* handled by local core */
+               if (local_irq & (0x1 << ht_irq[i])) {
+                       do_IRQ(ht_irq[i]);
+                       continue;
+               }
 
-       dest_cpu = dest_cpu + 1;
-       if (dest_cpu >= num_possible_cpus() || cpu_data[dest_cpu].package > 0)
-               dest_cpu = 0;
+               irqd = irq_get_irq_data(ht_irq[i]);
+               cpumask_and(&affinity, irqd->common->affinity, cpu_active_mask);
+               if (cpumask_empty(&affinity)) {
+                       do_IRQ(ht_irq[i]);
+                       continue;
+               }
 
-       for (i = 0; i < ARRAY_SIZE(ht_irq); i++) {
-               if (irq0 & (0x1 << ht_irq[i]))
+               irq_cpu[ht_irq[i]] = cpumask_next(irq_cpu[ht_irq[i]], &affinity);
+               if (irq_cpu[ht_irq[i]] >= nr_cpu_ids)
+                       irq_cpu[ht_irq[i]] = cpumask_first(&affinity);
+
+               if (irq_cpu[ht_irq[i]] == 0) {
                        do_IRQ(ht_irq[i]);
+                       continue;
+               }
+
+               /* balanced by other cores */
+               loongson3_send_irq_by_ipi(irq_cpu[ht_irq[i]], (0x1 << ht_irq[i]));
        }
 }
 
@@ -135,11 +171,16 @@ void irq_router_init(void)
 
 void __init mach_init_irq(void)
 {
+       struct irq_chip *chip;
+
        clear_c0_status(ST0_IM | ST0_BEV);
 
        irq_router_init();
        mips_cpu_irq_init();
        init_i8259_irqs();
+       chip = irq_get_chip(I8259A_IRQ_BASE);
+       chip->irq_set_affinity = plat_set_irq_affinity;
+
        irq_set_chip_and_handler(LOONGSON_UART_IRQ,
                        &loongson_irq_chip, handle_level_irq);