irqchip: dw-apb-ictl: Add PM support

This patch adds in support for S2R for dw-apb-ictl irqchip driver.

We can used relaxed variants in the resume hook because there's no DMA
at all here, the device type memory attribute can ensure the operations
order and relaxed version imply compiler barrier.

Signed-off-by: Jisheng Zhang <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Jason Cooper <[email protected]>

drivers/irqchip/irq-dw-apb-ictl.c

@@ -50,6 +50,21 @@ static void dw_apb_ictl_handler(unsigned int irq, struct irq_desc *desc)
 	chained_irq_exit(chip, desc);
 }
 
+#ifdef CONFIG_PM
+static void dw_apb_ictl_resume(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct irq_chip_type *ct = irq_data_get_chip_type(d);
+
+	irq_gc_lock(gc);
+	writel_relaxed(~0, gc->reg_base + ct->regs.enable);
+	writel_relaxed(*ct->mask_cache, gc->reg_base + ct->regs.mask);
+	irq_gc_unlock(gc);
+}
+#else
+#define dw_apb_ictl_resume	NULL
+#endif /* CONFIG_PM */
+
 static int __init dw_apb_ictl_init(struct device_node *np,
 				   struct device_node *parent)
 {
@@ -127,13 +142,17 @@ static int __init dw_apb_ictl_init(struct device_node *np,
 	gc->reg_base = iobase;
 
 	gc->chip_types[0].regs.mask = APB_INT_MASK_L;
+	gc->chip_types[0].regs.enable = APB_INT_ENABLE_L;
 	gc->chip_types[0].chip.irq_mask = irq_gc_mask_set_bit;
 	gc->chip_types[0].chip.irq_unmask = irq_gc_mask_clr_bit;
+	gc->chip_types[0].chip.irq_resume = dw_apb_ictl_resume;
 
 	if (nrirqs > 32) {
 		gc->chip_types[1].regs.mask = APB_INT_MASK_H;
+		gc->chip_types[1].regs.enable = APB_INT_ENABLE_H;
 		gc->chip_types[1].chip.irq_mask = irq_gc_mask_set_bit;
 		gc->chip_types[1].chip.irq_unmask = irq_gc_mask_clr_bit;
+		gc->chip_types[1].chip.irq_resume = dw_apb_ictl_resume;
 	}
 
 	irq_set_handler_data(irq, gc);