On Fri, 03 Dec 2021 07:34:25 +0000,
Qin Jian [off-list ref] wrote:

__assign_bit() on an MMIO mapping? No. Why do you think we have
separate MMIO accessors?

+	raw_spin_unlock_irqrestore(&sp_intc.lock, flags);
+}
+
+static void sp_intc_ack_irq(struct irq_data *d)
+{
+	u32 hwirq = d->hwirq;
+
+	if (unlikely(IS_GPIO_INT(hwirq) && TEST_STATE(hwirq, _IS_EDGE))) { // WORKAROUND
+		sp_intc_assign_bit(hwirq, REG_INTR_POLARITY, !TEST_STATE(hwirq, _IS_LOW));
+		ASSIGN_STATE(hwirq, _IS_ACTIVE, true);
+	}
+
+	sp_intc_assign_bit(hwirq, REG_INTR_CLEAR, 1);
+}
+
+static void sp_intc_mask_irq(struct irq_data *d)
+{
+	sp_intc_assign_bit(d->hwirq, REG_INTR_MASK, 0);
+}
+
+static void sp_intc_unmask_irq(struct irq_data *d)
+{
+	sp_intc_assign_bit(d->hwirq, REG_INTR_MASK, 1);
+}
+
+static int sp_intc_set_type(struct irq_data *d, unsigned int type)
+{
+	u32 hwirq = d->hwirq;
+	bool is_edge = !(type & IRQ_TYPE_LEVEL_MASK);
+	bool is_low = (type == IRQ_TYPE_LEVEL_LOW || type == IRQ_TYPE_EDGE_FALLING);
+
+	irq_set_handler_locked(d, is_edge ? handle_edge_irq : handle_level_irq);
+
+	if (unlikely(IS_GPIO_INT(hwirq) && is_edge)) { // WORKAROUND
+		/* store states */
+		ASSIGN_STATE(hwirq, _IS_EDGE, is_edge);
+		ASSIGN_STATE(hwirq, _IS_LOW, is_low);
+		ASSIGN_STATE(hwirq, _IS_ACTIVE, false);
+		/* change to level */
+		is_edge = false;
+	}
+
+	sp_intc_assign_bit(hwirq, REG_INTR_TYPE, is_edge);
+	sp_intc_assign_bit(hwirq, REG_INTR_POLARITY, is_low);
+
+	return 0;
+}
+
+static int sp_intc_get_ext_irq(int ext_num)
+{
+	void __iomem *base = ext_num ? REG_MASKED_EXT1 : REG_MASKED_EXT0;
+	u32 shift = ext_num ? GROUP_SHIFT_EXT1 : GROUP_SHIFT_EXT0;
+	u32 groups;
+	u32 pending_group;
+	u32 group;
+	u32 pending_irq;
+
+	groups = readl_relaxed(REG_INTR_GROUP);
+	pending_group = (groups >> shift) & GROUP_MASK;
+	if (!pending_group)
+		return -1;
+
+	group = fls(pending_group) - 1;
+	pending_irq = readl_relaxed(base + group * 4);
+	if (!pending_irq)
+		return -1;
+
+	return (group * 32) + fls(pending_irq) - 1;
+}
+
+static void sp_intc_handle_ext_cascaded(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	int ext_num = (int)irq_desc_get_handler_data(desc);
+	int hwirq;
+
+	chained_irq_enter(chip, desc);
+
+	while ((hwirq = sp_intc_get_ext_irq(ext_num)) >= 0) {
+		if (unlikely(IS_GPIO_INT(hwirq) && TEST_STATE(hwirq, _IS_ACTIVE))) { // WORKAROUND
+			ASSIGN_STATE(hwirq, _IS_ACTIVE, false);
+			sp_intc_assign_bit(hwirq, REG_INTR_POLARITY, TEST_STATE(hwirq, _IS_LOW));
+		} else {
+			generic_handle_domain_irq(sp_intc.domain, hwirq);
+		}
+	}
+
+	chained_irq_exit(chip, desc);
+}
+
+#ifdef CONFIG_SMP
+static int sp_intc_set_affinity(struct irq_data *d, const struct cpumask *mask, bool force)
+{
+	return -EINVAL;
+}
+#endif
+
+static struct irq_chip sp_intc_chip = {
+	.name = "sp_intc",
+	.irq_ack = sp_intc_ack_irq,
+	.irq_mask = sp_intc_mask_irq,
+	.irq_unmask = sp_intc_unmask_irq,
+	.irq_set_type = sp_intc_set_type,
+#ifdef CONFIG_SMP
+	.irq_set_affinity = sp_intc_set_affinity,
+#endif
+};
+
+static int sp_intc_irq_domain_map(struct irq_domain *domain,
+				  unsigned int irq, irq_hw_number_t hwirq)
+{
+	irq_set_chip_and_handler(irq, &sp_intc_chip, handle_level_irq);
+	irq_set_chip_data(irq, &sp_intc_chip);
+	irq_set_noprobe(irq);
+
+	return 0;
+}
+
+static const struct irq_domain_ops sp_intc_dm_ops = {
+	.xlate = irq_domain_xlate_twocell,
+	.map = sp_intc_irq_domain_map,
+};
+
+static int sp_intc_irq_map(struct device_node *node, int i)
+{
+	unsigned int irq;
+
+	irq = irq_of_parse_and_map(node, i);
+	if (!irq)
+		return -ENOENT;
+
+	irq_set_chained_handler_and_data(irq, sp_intc_handle_ext_cascaded, (void *)i);
+
+	return 0;
+}
+
+void sp_intc_set_ext(u32 hwirq, int ext_num)
+{
+	sp_intc_assign_bit(hwirq, REG_INTR_PRIORITY, !ext_num);
+}
+EXPORT_SYMBOL_GPL(sp_intc_set_ext);

No way. We don't export random symbols without a good justification,
and you didn't give any.

+
+int __init sp_intc_init_dt(struct device_node *node, struct device_node *parent)

This should be static.

+{
+	int i, ret;
+
+	sp_intc.g0 = of_iomap(node, 0);
+	if (!sp_intc.g0)
+		return -ENXIO;
+
+	sp_intc.g1 = of_iomap(node, 1);
+	if (!sp_intc.g1) {
+		ret = -ENXIO;
+		goto out_unmap0;
+	}
+
+	ret = sp_intc_irq_map(node, 0); // EXT_INT0
+	if (ret)
+		goto out_unmap1;
+
+	ret = sp_intc_irq_map(node, 1); // EXT_INT1
+	if (ret)
+		goto out_unmap1;
+
+	/* initial regs */
+	for (i = 0; i < SP_INTC_NR_GROUPS; i++) {
+		/* all mask */
+		writel_relaxed(0, REG_INTR_MASK + i * 4);
+		/* all edge */
+		writel_relaxed(~0, REG_INTR_TYPE + i * 4);
+		/* all high-active */
+		writel_relaxed(0, REG_INTR_POLARITY + i * 4);
+		/* all EXT_INT0 */
+		writel_relaxed(~0, REG_INTR_PRIORITY + i * 4);
+		/* all clear */
+		writel_relaxed(~0, REG_INTR_CLEAR + i * 4);
+	}
+
+	sp_intc.domain = irq_domain_add_linear(node, SP_INTC_NR_IRQS,
+					       &sp_intc_dm_ops, &sp_intc);
+	if (!sp_intc.domain) {
+		ret = -ENOMEM;
+		goto out_unmap1;
+	}
+
+	raw_spin_lock_init(&sp_intc.lock);
+
+	return 0;
+
+out_unmap1:
+	iounmap(sp_intc.g1);
+out_unmap0:
+	iounmap(sp_intc.g0);
+
+	return ret;
+}
+
+IRQCHIP_DECLARE(sp_intc, "sunplus,sp7021-intc", sp_intc_init_dt);

	M.

-- 
Without deviation from the norm, progress is not possible.