[PATCH v6 7/7] irqchip: s3c24xx: add devicetree support

["Heiko Stübner" <heiko@sntech.de>]

Add the necessary code to initialize the interrupt controller
thru devicetree data using the irqchip infrastructure.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
---
 .../interrupt-controller/samsung,s3c24xx-irq.txt   |   53 +++++
 drivers/irqchip/irq-s3c24xx.c                      |  231 +++++++++++++++++++-
 2 files changed, 278 insertions(+), 6 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/interrupt-controller/samsung,s3c24xx-irq.txt

diff --git a/Documentation/devicetree/bindings/interrupt-controller/samsung,s3c24xx-irq.txt b/Documentation/devicetree/bindings/interrupt-controller/samsung,s3c24xx-irq.txt
new file mode 100644
index 0000000..c54c5a9
--- /dev/null
+++ b/Documentation/devicetree/bindings/interrupt-controller/samsung,s3c24xx-irq.txt
@@ -0,0 +1,53 @@
+Samsung S3C24XX Interrupt Controllers
+
+The S3C24XX SoCs contain a custom set of interrupt controllers providing a
+varying number of interrupt sources. The set consists of a main- and sub-
+controller and on newer SoCs even a second main controller.
+
+Required properties:
+- compatible: Compatible property value should be "samsung,s3c2410-irq"
+  for machines before s3c2416 and "samsung,s3c2416-irq" for s3c2416 and later.
+
+- reg: Physical base address of the controller and length of memory mapped
+  region.
+
+- interrupt-controller : Identifies the node as an interrupt controller
+
+- #interrupt-cells : Specifies the number of cells needed to encode an
+  interrupt source. The value shall be 4 and interrupt descriptor shall
+  have the following format:
+      <ctrl_num parent_irq ctrl_irq type>
+
+  ctrl_num contains the controller to use:
+      - 0 ... main controller
+      - 1 ... sub controller
+      - 2 ... second main controller on s3c2416 and s3c2450
+  parent_irq contains the parent bit in the main controller and will be
+             ignored in main controllers
+  ctrl_irq contains the interrupt bit of the controller
+  type contains the trigger type to use
+
+Example:
+
+	interrupt-controller@4a000000 {
+		compatible = "samsung,s3c2410-irq";
+		reg = <0x4a000000 0x100>;
+		interrupt-controller;
+		#interrupt-cells=<4>;
+	};
+
+	[...]
+
+	serial@50000000 {
+		compatible = "samsung,s3c2410-uart";
+		reg = <0x50000000 0x4000>;
+		interrupt-parent = <&subintc>;
+		interrupts = <1 28 0 4>, <1 28 1 4>;
+	};
+
+	rtc@57000000 {
+		compatible = "samsung,s3c2410-rtc";
+		reg = <0x57000000 0x100>;
+		interrupt-parent = <&intc>;
+		interrupts = <0 30 0 3>, <0 8 0 3>;
+	};
diff --git a/drivers/irqchip/irq-s3c24xx.c b/drivers/irqchip/irq-s3c24xx.c
index 02b82db..5e40b34 100644
--- a/drivers/irqchip/irq-s3c24xx.c
+++ b/drivers/irqchip/irq-s3c24xx.c
@@ -25,6 +25,9 @@
 #include <linux/ioport.h>
 #include <linux/device.h>
 #include <linux/irqdomain.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
 
 #include <asm/exception.h>
 #include <asm/mach/irq.h>
@@ -36,6 +39,8 @@
 #include <plat/regs-irqtype.h>
 #include <plat/pm.h>
 
+#include "irqchip.h"
+
 #define S3C_IRQTYPE_NONE	0
 #define S3C_IRQTYPE_EINT	1
 #define S3C_IRQTYPE_EDGE	2
@@ -94,7 +99,10 @@ static void s3c_irq_mask(struct irq_data *data)
 	if (parent_intc) {
 		parent_data = &parent_intc->irqs[irq_data->parent_irq];
 
-		/* check to see if we need to mask the parent IRQ */
+		/* check to see if we need to mask the parent IRQ
+		 * The parent_irq is always in main_intc, so the hwirq
+		 * for find_mapping does not need an offset in any case.
+		 */
 		if ((mask & parent_data->sub_bits) == parent_data->sub_bits) {
 			irqno = irq_find_mapping(parent_intc->domain,
 					 irq_data->parent_irq);
@@ -294,10 +302,18 @@ static void s3c_irq_demux(unsigned int irq, struct irq_desc *desc)
 {
 	struct irq_chip *chip = irq_desc_get_chip(desc);
 	struct s3c_irq_data *irq_data = irq_desc_get_chip_data(desc);
+	struct s3c_irq_intc *intc = irq_data->intc;
 	struct s3c_irq_intc *sub_intc = irq_data->sub_intc;
 	unsigned long src;
 	unsigned long msk;
 	unsigned int n;
+	unsigned int offset;
+
+	/* we're using individual domains for the non-dt case
+	 * and one big domain for the dt case where the subintc
+	 * starts at hwirq number 32.
+	 */
+	offset = (intc->domain->of_node) ? 32 : 0;
 
 	chained_irq_enter(chip, desc);
 
@@ -310,14 +326,15 @@ static void s3c_irq_demux(unsigned int irq, struct irq_desc *desc)
 	while (src) {
 		n = __ffs(src);
 		src &= ~(1 << n);
-		generic_handle_irq(irq_find_mapping(sub_intc->domain, n));
+		irq = irq_find_mapping(sub_intc->domain, offset + n);
+		generic_handle_irq(irq);
 	}
 
 	chained_irq_exit(chip, desc);
 }
 
 static inline int s3c24xx_handle_intc(struct s3c_irq_intc *intc,
-				      struct pt_regs *regs)
+				      struct pt_regs *regs, int intc_offset)
 {
 	int pnd;
 	int offset;
@@ -327,6 +344,10 @@ static inline int s3c24xx_handle_intc(struct s3c_irq_intc *intc,
 	if (!pnd)
 		return false;
 
+	/* non-dt machines use individual domains */
+	if (!intc->domain->of_node)
+		intc_offset = 0;
+
 	/* We have a problem that the INTOFFSET register does not always
 	 * show one interrupt. Occasionally we get two interrupts through
 	 * the prioritiser, and this causes the INTOFFSET register to show
@@ -343,7 +364,7 @@ static inline int s3c24xx_handle_intc(struct s3c_irq_intc *intc,
 	if (!(pnd & (1 << offset)))
 		offset =  __ffs(pnd);
 
-	irq = irq_find_mapping(intc->domain, offset);
+	irq = irq_find_mapping(intc->domain, intc_offset + offset);
 	handle_IRQ(irq, regs);
 	return true;
 }
@@ -352,11 +373,11 @@ asmlinkage void __exception_irq_entry s3c24xx_handle_irq(struct pt_regs *regs)
 {
 	do {
 		if (likely(s3c_intc[0]))
-			if (s3c24xx_handle_intc(s3c_intc[0], regs))
+			if (s3c24xx_handle_intc(s3c_intc[0], regs, 0))
 				continue;
 
 		if (s3c_intc[2])
-			if (s3c24xx_handle_intc(s3c_intc[2], regs))
+			if (s3c24xx_handle_intc(s3c_intc[2], regs, 64))
 				continue;
 
 		break;
@@ -1134,3 +1155,201 @@ void __init s3c2443_init_irq(void)
 					s3c_intc[0], 0x4a000018);
 }
 #endif
+
+#ifdef CONFIG_OF
+static int s3c24xx_irq_map_of(struct irq_domain *h, unsigned int virq,
+							irq_hw_number_t hw)
+{
+	unsigned int ctrl_num = hw / 32;
+	unsigned int intc_hw = hw % 32;
+	struct s3c_irq_intc *intc = s3c_intc[ctrl_num];
+	struct s3c_irq_intc *parent_intc = intc->parent;
+	struct s3c_irq_data *irq_data = &intc->irqs[intc_hw];
+
+	/* attach controller pointer to irq_data */
+	irq_data->intc = intc;
+	irq_data->offset = intc_hw;
+
+	if (!parent_intc)
+		irq_set_chip_and_handler(virq, &s3c_irq_chip, handle_edge_irq);
+	else
+		irq_set_chip_and_handler(virq, &s3c_irq_level_chip,
+					 handle_edge_irq);
+
+	irq_set_chip_data(virq, irq_data);
+
+	set_irq_flags(virq, IRQF_VALID);
+
+	return 0;
+}
+
+/* Translate our of irq notation
+ * format: <ctrl_num ctrl_irq parent_irq type>
+ */
+static int s3c24xx_irq_xlate_of(struct irq_domain *d, struct device_node *n,
+			const u32 *intspec, unsigned int intsize,
+			irq_hw_number_t *out_hwirq, unsigned int *out_type)
+{
+	struct s3c_irq_intc *intc;
+	struct s3c_irq_intc *parent_intc;
+	struct s3c_irq_data *irq_data;
+	struct s3c_irq_data *parent_irq_data;
+	int irqno;
+
+	if (WARN_ON(intsize < 4))
+		return -EINVAL;
+
+	if (intspec[0] > 2 || !s3c_intc[intspec[0]]) {
+		pr_err("controller number %d invalid\n", intspec[0]);
+		return -EINVAL;
+	}
+	intc = s3c_intc[intspec[0]];
+
+	*out_hwirq = intspec[0] * 32 + intspec[2];
+	*out_type = intspec[3] & IRQ_TYPE_SENSE_MASK;
+
+	parent_intc = intc->parent;
+	if (parent_intc) {
+		irq_data = &intc->irqs[intspec[2]];
+		irq_data->parent_irq = intspec[1];
+		parent_irq_data = &parent_intc->irqs[irq_data->parent_irq];
+		parent_irq_data->sub_intc = intc;
+		parent_irq_data->sub_bits |= (1UL << intspec[2]);
+
+		/* parent_intc is always s3c_intc[0], so no offset */
+		irqno = irq_create_mapping(parent_intc->domain, intspec[1]);
+		if (irqno < 0) {
+			pr_err("irq: could not map parent interrupt\n");
+			return irqno;
+		}
+
+		irq_set_chained_handler(irqno, s3c_irq_demux);
+	}
+
+	return 0;
+}
+
+static struct irq_domain_ops s3c24xx_irq_ops_of = {
+	.map = s3c24xx_irq_map_of,
+	.xlate = s3c24xx_irq_xlate_of,
+};
+
+struct s3c24xx_irq_of_ctrl {
+	char			*name;
+	unsigned long		offset;
+	struct s3c_irq_intc	**handle;
+	struct s3c_irq_intc	**parent;
+	struct irq_domain_ops	*ops;
+};
+
+static int __init s3c_init_intc_of(struct device_node *np,
+			struct device_node *interrupt_parent,
+			struct s3c24xx_irq_of_ctrl *s3c_ctrl, int num_ctrl)
+{
+	struct s3c_irq_intc *intc;
+	struct s3c24xx_irq_of_ctrl *ctrl;
+	struct irq_domain *domain;
+	void __iomem *reg_base;
+	int i;
+
+	reg_base = of_iomap(np, 0);
+	if (!reg_base) {
+		pr_err("irq-s3c24xx: could not map irq registers\n");
+		return -EINVAL;
+	}
+
+	domain = irq_domain_add_linear(np, num_ctrl * 32,
+						     &s3c24xx_irq_ops_of, NULL);
+	if (!domain) {
+		pr_err("irq: could not create irq-domain\n");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < num_ctrl; i++) {
+		ctrl = &s3c_ctrl[i];
+
+		pr_debug("irq: found controller %s\n", ctrl->name);
+
+		intc = kzalloc(sizeof(struct s3c_irq_intc), GFP_KERNEL);
+		if (!intc)
+			return -ENOMEM;
+
+		intc->domain = domain;
+		intc->irqs = kzalloc(sizeof(struct s3c_irq_data) * 32,
+				     GFP_KERNEL);
+		if (!intc->irqs) {
+			kfree(intc);
+			return -ENOMEM;
+		}
+
+		if (ctrl->parent) {
+			intc->reg_pending = reg_base + ctrl->offset;
+			intc->reg_mask = reg_base + ctrl->offset + 0x4;
+
+			if (*(ctrl->parent)) {
+				intc->parent = *(ctrl->parent);
+			} else {
+				pr_warn("irq: parent of %s missing\n",
+					ctrl->name);
+				kfree(intc->irqs);
+				kfree(intc);
+				continue;
+			}
+		} else {
+			intc->reg_pending = reg_base + ctrl->offset;
+			intc->reg_mask = reg_base + ctrl->offset + 0x08;
+			intc->reg_intpnd = reg_base + ctrl->offset + 0x10;
+		}
+
+		s3c24xx_clear_intc(intc);
+		s3c_intc[i] = intc;
+	}
+
+	set_handle_irq(s3c24xx_handle_irq);
+
+	return 0;
+}
+
+static struct s3c24xx_irq_of_ctrl s3c2410_ctrl[] = {
+	{
+		.name = "intc",
+		.offset = 0,
+	}, {
+		.name = "subintc",
+		.offset = 0x18,
+		.parent = &s3c_intc[0],
+	}
+};
+
+int __init s3c2410_init_intc_of(struct device_node *np,
+			struct device_node *interrupt_parent,
+			struct s3c24xx_irq_of_ctrl *ctrl, int num_ctrl)
+{
+	return s3c_init_intc_of(np, interrupt_parent,
+				s3c2410_ctrl, ARRAY_SIZE(s3c2410_ctrl));
+}
+IRQCHIP_DECLARE(s3c2410_irq, "samsung,s3c2410-irq", s3c2410_init_intc_of);
+
+static struct s3c24xx_irq_of_ctrl s3c2416_ctrl[] = {
+	{
+		.name = "intc",
+		.offset = 0,
+	}, {
+		.name = "subintc",
+		.offset = 0x18,
+		.parent = &s3c_intc[0],
+	}, {
+		.name = "intc2",
+		.offset = 0x40,
+	}
+};
+
+int __init s3c2416_init_intc_of(struct device_node *np,
+			struct device_node *interrupt_parent,
+			struct s3c24xx_irq_of_ctrl *ctrl, int num_ctrl)
+{
+	return s3c_init_intc_of(np, interrupt_parent,
+				s3c2416_ctrl, ARRAY_SIZE(s3c2416_ctrl));
+}
+IRQCHIP_DECLARE(s3c2416_irq, "samsung,s3c2416-irq", s3c2416_init_intc_of);
+#endif
-- 
1.7.10.4