[POWERPC] ps3: cleanup interrupt bmp routines

Change the PS3 interrupt bitmask routines to be lockless.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
Acked-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --git a/arch/powerpc/platforms/ps3/interrupt.c b/arch/powerpc/platforms/ps3/interrupt.c
index 7a4ca056dd3a1337ea5f33bc3aa0566749d98874..d3c97fbff7ef6263f35c4985ba370232d6cc0fcc 100644 (file)
--- a/arch/powerpc/platforms/ps3/interrupt.c
+++ b/arch/powerpc/platforms/ps3/interrupt.c
@@ -380,34 +380,50 @@ static void dump_bmp(struct ps3_private* pd) {};
 
 static void ps3_chip_mask(unsigned int virq)
 {
-       unsigned long flags;
        struct ps3_private *pd = get_irq_chip_data(virq);
+       unsigned long bit = 0x8000000000000000UL >> virq;
+       unsigned long *p = &pd->bmp.mask;
+       unsigned long old;
+       unsigned long flags;
 
        pr_debug("%s:%d: cpu %u, virq %d\n", __func__, __LINE__, pd->cpu, virq);
 
-       BUG_ON(virq < NUM_ISA_INTERRUPTS);
-       BUG_ON(virq > PS3_PLUG_MAX);
+       local_irq_save(flags);
+       asm volatile(
+                    "1:        ldarx %0,0,%3\n"
+                    "andc      %0,%0,%2\n"
+                    "stdcx.    %0,0,%3\n"
+                    "bne-      1b"
+                    : "=&r" (old), "+m" (*p)
+                    : "r" (bit), "r" (p)
+                    : "cc" );
 
-       spin_lock_irqsave(&pd->bmp.lock, flags);
-       pd->bmp.mask &= ~(0x8000000000000000UL >> virq);
        lv1_did_update_interrupt_mask(pd->node, pd->cpu);
-       spin_unlock_irqrestore(&pd->bmp.lock, flags);
+       local_irq_restore(flags);
 }
 
 static void ps3_chip_unmask(unsigned int virq)
 {
-       unsigned long flags;
        struct ps3_private *pd = get_irq_chip_data(virq);
+       unsigned long bit = 0x8000000000000000UL >> virq;
+       unsigned long *p = &pd->bmp.mask;
+       unsigned long old;
+       unsigned long flags;
 
        pr_debug("%s:%d: cpu %u, virq %d\n", __func__, __LINE__, pd->cpu, virq);
 
-       BUG_ON(virq < NUM_ISA_INTERRUPTS);
-       BUG_ON(virq > PS3_PLUG_MAX);
+       local_irq_save(flags);
+       asm volatile(
+                    "1:        ldarx %0,0,%3\n"
+                    "or        %0,%0,%2\n"
+                    "stdcx.    %0,0,%3\n"
+                    "bne-      1b"
+                    : "=&r" (old), "+m" (*p)
+                    : "r" (bit), "r" (p)
+                    : "cc" );
 
-       spin_lock_irqsave(&pd->bmp.lock, flags);
-       pd->bmp.mask |= (0x8000000000000000UL >> virq);
        lv1_did_update_interrupt_mask(pd->node, pd->cpu);
-       spin_unlock_irqrestore(&pd->bmp.lock, flags);
+       local_irq_restore(flags);
 }
 
 static void ps3_chip_eoi(unsigned int virq)
@@ -481,46 +497,21 @@ void __init ps3_register_ipi_debug_brk(unsigned int cpu, unsigned int virq)
                cpu, virq, pd->bmp.ipi_debug_brk_mask);
 }
 
-static int bmp_get_and_clear_status_bit(struct ps3_bmp *m)
+unsigned int ps3_get_irq(void)
 {
-       unsigned long flags;
-       unsigned int bit;
-       unsigned long x;
-
-       spin_lock_irqsave(&m->lock, flags);
+       struct ps3_private *pd = &__get_cpu_var(ps3_private);
+       unsigned long x = (pd->bmp.status & pd->bmp.mask);
+       unsigned int plug;
 
        /* check for ipi break first to stop this cpu ASAP */
 
-       if (m->status & m->ipi_debug_brk_mask) {
-               m->status &= ~m->ipi_debug_brk_mask;
-               spin_unlock_irqrestore(&m->lock, flags);
-               return __ilog2(m->ipi_debug_brk_mask);
-       }
-
-       x = (m->status & m->mask);
-
-       for (bit = NUM_ISA_INTERRUPTS, x <<= bit; x; bit++, x <<= 1)
-               if (x & 0x8000000000000000UL) {
-                       m->status &= ~(0x8000000000000000UL >> bit);
-                       spin_unlock_irqrestore(&m->lock, flags);
-                       return bit;
-               }
-
-       spin_unlock_irqrestore(&m->lock, flags);
-
-       pr_debug("%s:%d: not found\n", __func__, __LINE__);
-       return -1;
-}
-
-unsigned int ps3_get_irq(void)
-{
-       int plug;
-
-       struct ps3_private *pd = &__get_cpu_var(ps3_private);
+       if (x & pd->bmp.ipi_debug_brk_mask)
+               x &= pd->bmp.ipi_debug_brk_mask;
 
-       plug = bmp_get_and_clear_status_bit(&pd->bmp);
+       asm volatile("cntlzd %0,%1" : "=r" (plug) : "r" (x));
+       plug &= 0x3f;
 
-       if (plug < 1) {
+       if (unlikely(plug) == NO_IRQ) {
                pr_debug("%s:%d: no plug found: cpu %u\n", __func__, __LINE__,
                        pd->cpu);
                dump_bmp(&per_cpu(ps3_private, 0));
@@ -529,7 +520,7 @@ unsigned int ps3_get_irq(void)
        }
 
 #if defined(DEBUG)
-       if (plug < NUM_ISA_INTERRUPTS || plug > PS3_PLUG_MAX) {
+       if (unlikely(plug < NUM_ISA_INTERRUPTS || plug > PS3_PLUG_MAX)) {
                dump_bmp(&per_cpu(ps3_private, 0));
                dump_bmp(&per_cpu(ps3_private, 1));
                BUG();