[RFC patch 3/8] genirq: generic chip: Handle separate mask registers

[Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>]

[-- Attachment #1: genirq-handle-separate-mask-registers.patch --]
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From: Gerlando Falauto <gerlando.falauto-SkAbAL50j+5BDgjK7y7TUQ@public.gmane.org>

There are cases where all irq_chip_type instances have separate mask
registers, making a shared mask register cache unsuitable for the
purpose.

Introduce a new flag IRQ_GC_MASK_CACHE_PER_TYPE. If set, point the per
chip mask pointer to the per chip private mask cache instead.

[ tglx: Simplified code, renamed flag and massaged changelog ]

Signed-off-by: Gerlando Falauto <gerlando.falauto-SkAbAL50j+5BDgjK7y7TUQ@public.gmane.org>
Cc: Lennert Buytenhek <kernel-OLH4Qvv75CYX/NnBR394Jw@public.gmane.org>
Cc: Simon Guinot <simon-jKBdWWKqtFpg9hUCZPvPmw@public.gmane.org>
Cc: Joey Oravec <joravec-Vf0cVmJFnCtWk0Htik3J/w@public.gmane.org>
Cc: Ben Dooks <ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>
Cc: Nicolas Pitre <nico-vtqb6HGKxmzR7s880joybQ@public.gmane.org>
Cc: Jason Cooper <jason-NLaQJdtUoK4Be96aLqz0jA@public.gmane.org>
Cc: Andrew Lunn <andrew-g2DYL2Zd6BY@public.gmane.org>
Cc: Holger Brunck <Holger.Brunck-SkAbAL50j+5BDgjK7y7TUQ@public.gmane.org>
Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Signed-off-by: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
---
 include/linux/irq.h       |    2 ++
 kernel/irq/generic-chip.c |   17 ++++++++++-------
 2 files changed, 12 insertions(+), 7 deletions(-)

Index: linux-2.6/include/linux/irq.h
===================================================================
--- linux-2.6.orig/include/linux/irq.h
+++ linux-2.6/include/linux/irq.h
@@ -704,10 +704,12 @@ struct irq_chip_generic {
  * @IRQ_GC_INIT_NESTED_LOCK:	Set the lock class of the irqs to nested for
  *				irq chips which need to call irq_set_wake() on
  *				the parent irq. Usually GPIO implementations
+ * @IRQ_GC_MASK_CACHE_PER_TYPE:	Mask cache is chip type private
  */
 enum irq_gc_flags {
 	IRQ_GC_INIT_MASK_CACHE		= 1 << 0,
 	IRQ_GC_INIT_NESTED_LOCK		= 1 << 1,
+	IRQ_GC_MASK_CACHE_PER_TYPE	= 1 << 2,
 };
 
 /* Generic chip callback functions */
Index: linux-2.6/kernel/irq/generic-chip.c
===================================================================
--- linux-2.6.orig/kernel/irq/generic-chip.c
+++ linux-2.6/kernel/irq/generic-chip.c
@@ -241,18 +241,21 @@ void irq_setup_generic_chip(struct irq_c
 {
 	struct irq_chip_type *ct = gc->chip_types;
 	unsigned int i;
+	u32 *mskptr = &gc->mask_cache, mskreg = ct->regs.mask;
 
 	raw_spin_lock(&gc_lock);
 	list_add_tail(&gc->list, &gc_list);
 	raw_spin_unlock(&gc_lock);
 
-	/* Init mask cache ? */
-	if (flags & IRQ_GC_INIT_MASK_CACHE)
-		gc->mask_cache = irq_reg_readl(gc->reg_base + ct->regs.mask);
-
-	/* Initialize mask cache pointer */
-	for (i = 0; i < gc->num_ct; i++)
-		ct[i].mask_cache = &gc->mask_cache;
+	for (i = 0; i < gc->num_ct; i++) {
+		if (flags & IRQ_GC_MASK_CACHE_PER_TYPE) {
+			mskptr = &ct[i].mask_cache_priv;
+			mskreg = ct[i].regs.mask;
+		}
+		ct[i].mask_cache = mskptr;
+		if (flags & IRQ_GC_INIT_MASK_CACHE)
+			*mskptr = irq_reg_readl(gc->reg_base + mskreg);
+	}
 
 	for (i = gc->irq_base; msk; msk >>= 1, i++) {
 		if (!(msk & 0x01))