genirq: replace irq_gc_ack() with {set,clr}_bit variants (fwd)

This fixes a regression introduced by e59347a1 "arm: orion:
Use generic irq chip".

Depending on the device, interrupts acknowledgement is done by setting
or by clearing a dedicated register. Replace irq_gc_ack() with some
{set,clr}_bit variants allows to handle both cases.

Note that this patch affects the following SoCs: Davinci, Samsung and
Orion. Except for this last, the change is minor: irq_gc_ack() is just
renamed into irq_gc_ack_set_bit().

For the Orion SoCs, the edge GPIO interrupts support is currently
broken. irq_gc_ack() try to acknowledge a such interrupt by setting
the corresponding cause register bit. The Orion GPIO device expect the
opposite. To fix this issue, the irq_gc_ack_clr_bit() variant is used.

Tested on Network Space v2.
Reported-by: Joey Oravec <joravec@drewtech.com>
Signed-off-by: Simon Guinot <sguinot@lacie.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/mach-davinci/irq.c

@@ -53,7 +53,7 @@ davinci_alloc_gc(void __iomem *base, unsigned int irq_start, unsigned int num)
 
 	gc = irq_alloc_generic_chip("AINTC", 1, irq_start, base, handle_edge_irq);
 	ct = gc->chip_types;
-	ct->chip.irq_ack = irq_gc_ack;
+	ct->chip.irq_ack = irq_gc_ack_set_bit;
 	ct->chip.irq_mask = irq_gc_mask_clr_bit;
 	ct->chip.irq_unmask = irq_gc_mask_set_bit;
 

arch/arm/plat-orion/gpio.c

@@ -432,7 +432,7 @@ void __init orion_gpio_init(int gpio_base, int ngpio,
 	ct->regs.mask = ochip->mask_offset + GPIO_EDGE_MASK_OFF;
 	ct->regs.ack = GPIO_EDGE_CAUSE_OFF;
 	ct->type = IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING;
-	ct->chip.irq_ack = irq_gc_ack;
+	ct->chip.irq_ack = irq_gc_ack_clr_bit;
 	ct->chip.irq_mask = irq_gc_mask_clr_bit;
 	ct->chip.irq_unmask = irq_gc_mask_set_bit;
 	ct->chip.irq_set_type = gpio_irq_set_type;

arch/arm/plat-s5p/irq-gpioint.c

@@ -152,7 +152,7 @@ static __init int s5p_gpioint_add(struct s3c_gpio_chip *chip)
 	if (!gc)
 		return -ENOMEM;
 	ct = gc->chip_types;
-	ct->chip.irq_ack = irq_gc_ack;
+	ct->chip.irq_ack = irq_gc_ack_set_bit;
 	ct->chip.irq_mask = irq_gc_mask_set_bit;
 	ct->chip.irq_unmask = irq_gc_mask_clr_bit;
 	ct->chip.irq_set_type = s5p_gpioint_set_type,

arch/arm/plat-samsung/irq-uart.c

@@ -55,7 +55,7 @@ static void __init s3c_init_uart_irq(struct s3c_uart_irq *uirq)
 	gc = irq_alloc_generic_chip("s3c-uart", 1, uirq->base_irq, reg_base,
 				    handle_level_irq);
 	ct = gc->chip_types;
-	ct->chip.irq_ack = irq_gc_ack;
+	ct->chip.irq_ack = irq_gc_ack_set_bit;
 	ct->chip.irq_mask = irq_gc_mask_set_bit;
 	ct->chip.irq_unmask = irq_gc_mask_clr_bit;
 	ct->regs.ack = S3C64XX_UINTP;

include/linux/irq.h

@@ -676,7 +676,8 @@ void irq_gc_mask_disable_reg(struct irq_data *d);
 void irq_gc_mask_set_bit(struct irq_data *d);
 void irq_gc_mask_clr_bit(struct irq_data *d);
 void irq_gc_unmask_enable_reg(struct irq_data *d);
-void irq_gc_ack(struct irq_data *d);
+void irq_gc_ack_set_bit(struct irq_data *d);
+void irq_gc_ack_clr_bit(struct irq_data *d);
 void irq_gc_mask_disable_reg_and_ack(struct irq_data *d);
 void irq_gc_eoi(struct irq_data *d);
 int irq_gc_set_wake(struct irq_data *d, unsigned int on);

kernel/irq/generic-chip.c

@@ -101,10 +101,10 @@ void irq_gc_unmask_enable_reg(struct irq_data *d)
 }
 
 /**
- * irq_gc_ack - Ack pending interrupt
+ * irq_gc_ack_set_bit - Ack pending interrupt via setting bit
  * @d: irq_data
  */
-void irq_gc_ack(struct irq_data *d)
+void irq_gc_ack_set_bit(struct irq_data *d)
 {
 	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
 	u32 mask = 1 << (d->irq - gc->irq_base);
@@ -114,6 +114,20 @@ void irq_gc_ack(struct irq_data *d)
 	irq_gc_unlock(gc);
 }
 
+/**
+ * irq_gc_ack_clr_bit - Ack pending interrupt via clearing bit
+ * @d: irq_data
+ */
+void irq_gc_ack_clr_bit(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	u32 mask = ~(1 << (d->irq - gc->irq_base));
+
+	irq_gc_lock(gc);
+	irq_reg_writel(mask, gc->reg_base + cur_regs(d)->ack);
+	irq_gc_unlock(gc);
+}
+
 /**
  * irq_gc_mask_disable_reg_and_ack- Mask and ack pending interrupt
  * @d: irq_data