irqchip/stm32: Add multi-bank management

-Prepare to manage multi-bank of external interrupts
(N banks of 32 inputs).
-Prepare to manage registers offsets by compatible
(registers offsets could be different follow per stm32 platform).
Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

drivers/irqchip/irq-stm32-exti.c

@@ -14,27 +14,66 @@
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 
-#define EXTI_IMR	0x0
-#define EXTI_EMR	0x4
-#define EXTI_RTSR	0x8
-#define EXTI_FTSR	0xc
-#define EXTI_SWIER	0x10
-#define EXTI_PR		0x14
+#define IRQS_PER_BANK 32
+
+struct stm32_exti_bank {
+	u32 imr_ofst;
+	u32 emr_ofst;
+	u32 rtsr_ofst;
+	u32 ftsr_ofst;
+	u32 swier_ofst;
+	u32 pr_ofst;
+};
+
+static const struct stm32_exti_bank stm32f4xx_exti_b1 = {
+	.imr_ofst	= 0x00,
+	.emr_ofst	= 0x04,
+	.rtsr_ofst	= 0x08,
+	.ftsr_ofst	= 0x0C,
+	.swier_ofst	= 0x10,
+	.pr_ofst	= 0x14,
+};
+
+static const struct stm32_exti_bank *stm32f4xx_exti_banks[] = {
+	&stm32f4xx_exti_b1,
+};
+
+static unsigned long stm32_exti_pending(struct irq_chip_generic *gc)
+{
+	const struct stm32_exti_bank *stm32_bank = gc->private;
+
+	return irq_reg_readl(gc, stm32_bank->pr_ofst);
+}
+
+static void stm32_exti_irq_ack(struct irq_chip_generic *gc, u32 mask)
+{
+	const struct stm32_exti_bank *stm32_bank = gc->private;
+
+	irq_reg_writel(gc, mask, stm32_bank->pr_ofst);
+}
 
 static void stm32_irq_handler(struct irq_desc *desc)
 {
 	struct irq_domain *domain = irq_desc_get_handler_data(desc);
-	struct irq_chip_generic *gc = domain->gc->gc[0];
 	struct irq_chip *chip = irq_desc_get_chip(desc);
+	unsigned int virq, nbanks = domain->gc->num_chips;
+	struct irq_chip_generic *gc;
+	const struct stm32_exti_bank *stm32_bank;
 	unsigned long pending;
-	int n;
+	int n, i, irq_base = 0;
 
 	chained_irq_enter(chip, desc);
 
-	while ((pending = irq_reg_readl(gc, EXTI_PR))) {
-		for_each_set_bit(n, &pending, BITS_PER_LONG) {
-			generic_handle_irq(irq_find_mapping(domain, n));
-			irq_reg_writel(gc, BIT(n), EXTI_PR);
+	for (i = 0; i < nbanks; i++, irq_base += IRQS_PER_BANK) {
+		gc = irq_get_domain_generic_chip(domain, irq_base);
+		stm32_bank = gc->private;
+
+		while ((pending = stm32_exti_pending(gc))) {
+			for_each_set_bit(n, &pending, IRQS_PER_BANK) {
+				virq = irq_find_mapping(domain, irq_base + n);
+				generic_handle_irq(virq);
+				stm32_exti_irq_ack(gc, BIT(n));
+			}
 		}
 	}
 
@@ -44,13 +83,14 @@ static void stm32_irq_handler(struct irq_desc *desc)
 static int stm32_irq_set_type(struct irq_data *data, unsigned int type)
 {
 	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
-	int pin = data->hwirq;
+	const struct stm32_exti_bank *stm32_bank = gc->private;
+	int pin = data->hwirq % IRQS_PER_BANK;
 	u32 rtsr, ftsr;
 
 	irq_gc_lock(gc);
 
-	rtsr = irq_reg_readl(gc, EXTI_RTSR);
-	ftsr = irq_reg_readl(gc, EXTI_FTSR);
+	rtsr = irq_reg_readl(gc, stm32_bank->rtsr_ofst);
+	ftsr = irq_reg_readl(gc, stm32_bank->ftsr_ofst);
 
 	switch (type) {
 	case IRQ_TYPE_EDGE_RISING:
@@ -70,8 +110,8 @@ static int stm32_irq_set_type(struct irq_data *data, unsigned int type)
 		return -EINVAL;
 	}
 
-	irq_reg_writel(gc, rtsr, EXTI_RTSR);
-	irq_reg_writel(gc, ftsr, EXTI_FTSR);
+	irq_reg_writel(gc, rtsr, stm32_bank->rtsr_ofst);
+	irq_reg_writel(gc, ftsr, stm32_bank->ftsr_ofst);
 
 	irq_gc_unlock(gc);
 
@@ -81,17 +121,18 @@ static int stm32_irq_set_type(struct irq_data *data, unsigned int type)
 static int stm32_irq_set_wake(struct irq_data *data, unsigned int on)
 {
 	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
-	int pin = data->hwirq;
+	const struct stm32_exti_bank *stm32_bank = gc->private;
+	int pin = data->hwirq % IRQS_PER_BANK;
 	u32 emr;
 
 	irq_gc_lock(gc);
 
-	emr = irq_reg_readl(gc, EXTI_EMR);
+	emr = irq_reg_readl(gc, stm32_bank->emr_ofst);
 	if (on)
 		emr |= BIT(pin);
 	else
 		emr &= ~BIT(pin);
-	irq_reg_writel(gc, emr, EXTI_EMR);
+	irq_reg_writel(gc, emr, stm32_bank->emr_ofst);
 
 	irq_gc_unlock(gc);
 
@@ -101,11 +142,12 @@ static int stm32_irq_set_wake(struct irq_data *data, unsigned int on)
 static int stm32_exti_alloc(struct irq_domain *d, unsigned int virq,
 			    unsigned int nr_irqs, void *data)
 {
-	struct irq_chip_generic *gc = d->gc->gc[0];
+	struct irq_chip_generic *gc;
 	struct irq_fwspec *fwspec = data;
 	irq_hw_number_t hwirq;
 
 	hwirq = fwspec->param[0];
+	gc = irq_get_domain_generic_chip(d, hwirq);
 
 	irq_map_generic_chip(d, virq, hwirq);
 	irq_domain_set_info(d, virq, hwirq, &gc->chip_types->chip, gc,
@@ -129,8 +171,9 @@ struct irq_domain_ops irq_exti_domain_ops = {
 	.free	= stm32_exti_free,
 };
 
-static int __init stm32_exti_init(struct device_node *node,
-				  struct device_node *parent)
+static int
+__init stm32_exti_init(const struct stm32_exti_bank **stm32_exti_banks,
+		       int bank_nr, struct device_node *node)
 {
 	unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
 	int nr_irqs, nr_exti, ret, i;
@@ -144,14 +187,7 @@ static int __init stm32_exti_init(struct device_node *node,
 		return -ENOMEM;
 	}
 
-	/* Determine number of irqs supported */
-	writel_relaxed(~0UL, base + EXTI_RTSR);
-	nr_exti = fls(readl_relaxed(base + EXTI_RTSR));
-	writel_relaxed(0, base + EXTI_RTSR);
-
-	pr_info("%pOF: %d External IRQs detected\n", node, nr_exti);
-
-	domain = irq_domain_add_linear(node, nr_exti,
+	domain = irq_domain_add_linear(node, bank_nr * IRQS_PER_BANK,
 				       &irq_exti_domain_ops, NULL);
 	if (!domain) {
 		pr_err("%s: Could not register interrupt domain.\n",
@@ -160,7 +196,7 @@ static int __init stm32_exti_init(struct device_node *node,
 		goto out_unmap;
 	}
 
-	ret = irq_alloc_domain_generic_chips(domain, nr_exti, 1, "exti",
+	ret = irq_alloc_domain_generic_chips(domain, IRQS_PER_BANK, 1, "exti",
 					     handle_edge_irq, clr, 0, 0);
 	if (ret) {
 		pr_err("%pOF: Could not allocate generic interrupt chip.\n",
@@ -168,18 +204,32 @@ static int __init stm32_exti_init(struct device_node *node,
 		goto out_free_domain;
 	}
 
-	gc = domain->gc->gc[0];
+	for (i = 0; i < bank_nr; i++) {
+		const struct stm32_exti_bank *stm32_bank = stm32_exti_banks[i];
+		u32 irqs_mask;
+
+		gc = irq_get_domain_generic_chip(domain, i * IRQS_PER_BANK);
+
 		gc->reg_base = base;
 		gc->chip_types->type = IRQ_TYPE_EDGE_BOTH;
-	gc->chip_types->chip.name          = gc->chip_types[0].chip.name;
 		gc->chip_types->chip.irq_ack = irq_gc_ack_set_bit;
 		gc->chip_types->chip.irq_mask = irq_gc_mask_clr_bit;
 		gc->chip_types->chip.irq_unmask = irq_gc_mask_set_bit;
 		gc->chip_types->chip.irq_set_type = stm32_irq_set_type;
 		gc->chip_types->chip.irq_set_wake = stm32_irq_set_wake;
-	gc->chip_types->regs.ack           = EXTI_PR;
-	gc->chip_types->regs.mask          = EXTI_IMR;
-	gc->chip_types->handler            = handle_edge_irq;
+		gc->chip_types->regs.ack = stm32_bank->pr_ofst;
+		gc->chip_types->regs.mask = stm32_bank->imr_ofst;
+		gc->private = (void *)stm32_bank;
+
+		/* Determine number of irqs supported */
+		writel_relaxed(~0UL, base + stm32_bank->rtsr_ofst);
+		irqs_mask = readl_relaxed(base + stm32_bank->rtsr_ofst);
+		nr_exti = fls(readl_relaxed(base + stm32_bank->rtsr_ofst));
+		writel_relaxed(0, base + stm32_bank->rtsr_ofst);
+
+		pr_info("%s: bank%d, External IRQs available:%#x\n",
+			node->full_name, i, irqs_mask);
+	}
 
 	nr_irqs = of_irq_count(node);
 	for (i = 0; i < nr_irqs; i++) {
@@ -198,4 +248,11 @@ static int __init stm32_exti_init(struct device_node *node,
 	return ret;
 }
 
-IRQCHIP_DECLARE(stm32_exti, "st,stm32-exti", stm32_exti_init);
+static int __init stm32f4_exti_of_init(struct device_node *np,
+				       struct device_node *parent)
+{
+	return stm32_exti_init(stm32f4xx_exti_banks,
+			ARRAY_SIZE(stm32f4xx_exti_banks), np);
+}
+
+IRQCHIP_DECLARE(stm32f4_exti, "st,stm32-exti", stm32f4_exti_of_init);