irqchip/loongson-liointc: Save/restore int_edge/int_pol registers during S3/S4

If int_edge/int_pol registers are configured to not be the default values, we
should save/restore them during S3/S4.

Signed-off-by: Yingkun Meng <[e-mail]>
Signed-off-by: Huacai Chen <[e-mail]>
Signed-off-by: Marc Zyngier <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/irqchip/irq-loongson-liointc.c

···
 	struct liointc_handler_data	handler[LIOINTC_NUM_PARENT];
 	void __iomem			*core_isr[LIOINTC_NUM_CORES];
 	u8				map_cache[LIOINTC_CHIP_IRQ];
+	u32				int_pol;
+	u32				int_edge;
 	bool				has_lpc_irq_errata;
 };
 
···
 	return 0;
 }
 
+static void liointc_suspend(struct irq_chip_generic *gc)
+{
+	struct liointc_priv *priv = gc->private;
+
+	priv->int_pol = readl(gc->reg_base + LIOINTC_REG_INTC_POL);
+	priv->int_edge = readl(gc->reg_base + LIOINTC_REG_INTC_EDGE);
+}
+
 static void liointc_resume(struct irq_chip_generic *gc)
 {
 	struct liointc_priv *priv = gc->private;
···
 	/* Restore map cache */
 	for (i = 0; i < LIOINTC_CHIP_IRQ; i++)
 		writeb(priv->map_cache[i], gc->reg_base + i);
+	writel(priv->int_pol, gc->reg_base + LIOINTC_REG_INTC_POL);
+	writel(priv->int_edge, gc->reg_base + LIOINTC_REG_INTC_EDGE);
 	/* Restore mask cache */
 	writel(gc->mask_cache, gc->reg_base + LIOINTC_REG_INTC_ENABLE);
 	irq_gc_unlock_irqrestore(gc, flags);
···
 	gc->private = priv;
 	gc->reg_base = base;
 	gc->domain = domain;
+	gc->suspend = liointc_suspend;
 	gc->resume = liointc_resume;
 
 	ct = gc->chip_types;