Merge branch 'irqchip/crossbar' into irqchip/core

2 files changed, 179 insertions, 25 deletions

diff --git a/Documentation/devicetree/bindings/arm/omap/crossbar.txt b/Documentation/devicetree/bindings/arm/omap/crossbar.txt
index fb88585..4139db3 100644
--- a/Documentation/devicetree/bindings/arm/omap/crossbar.txt
+++ b/Documentation/devicetree/bindings/arm/omap/crossbar.txt
@@ -10,6 +10,7 @@ Required properties:
 - compatible : Should be "ti,irq-crossbar"
 - reg: Base address and the size of the crossbar registers.
 - ti,max-irqs: Total number of irqs available at the interrupt controller.
+- ti,max-crossbar-sources: Maximum number of crossbar sources that can be routed.
 - ti,reg-size: Size of a individual register in bytes. Every individual
 	    register is assumed to be of same size. Valid sizes are 1, 2, 4.
 - ti,irqs-reserved: List of the reserved irq lines that are not muxed using
@@ -17,11 +18,46 @@ Required properties:
 		 so crossbar bar driver should not consider them as free
 		 lines.
 
+Optional properties:
+- ti,irqs-skip: This is similar to "ti,irqs-reserved", but these are for
+  SOC-specific hard-wiring of those irqs which unexpectedly bypasses the
+  crossbar. These irqs have a crossbar register, but still cannot be used.
+
+- ti,irqs-safe-map: integer which maps to a safe configuration to use
+  when the interrupt controller irq is unused (when not provided, default is 0)
+
 Examples:
 		crossbar_mpu: @4a020000 {
 			compatible = "ti,irq-crossbar";
 			reg = <0x4a002a48 0x130>;
 			ti,max-irqs = <160>;
+			ti,max-crossbar-sources = <400>;
 			ti,reg-size = <2>;
 			ti,irqs-reserved = <0 1 2 3 5 6 131 132 139 140>;
+			ti,irqs-skip = <10 133 139 140>;
 		};
+
+Consumer:
+========
+See Documentation/devicetree/bindings/interrupt-controller/interrupts.txt and
+Documentation/devicetree/bindings/arm/gic.txt for further details.
+
+An interrupt consumer on an SoC using crossbar will use:
+	interrupts = <GIC_SPI request_number interrupt_level>
+When the request number is between 0 to that described by
+"ti,max-crossbar-sources", it is assumed to be a crossbar mapping. If the
+request_number is greater than "ti,max-crossbar-sources", then it is mapped as a
+quirky hardware mapping direct to GIC.
+
+Example:
+	device_x@0x4a023000 {
+		/* Crossbar 8 used */
+		interrupts = <GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>;
+		...
+	};
+
+	device_y@0x4a033000 {
+		/* Direct mapped GIC SPI 1 used */
+		interrupts = <GIC_SPI DIRECT_IRQ(1) IRQ_TYPE_LEVEL_HIGH>;
+		...
+	};
diff --git a/drivers/irqchip/irq-crossbar.c b/drivers/irqchip/irq-crossbar.c
index 3d15d16..85c2985 100644
--- a/drivers/irqchip/irq-crossbar.c
+++ b/drivers/irqchip/irq-crossbar.c
@@ -15,22 +15,31 @@
 #include <linux/of_irq.h>
 #include <linux/slab.h>
 #include <linux/irqchip/arm-gic.h>
+#include <linux/irqchip/irq-crossbar.h>
 
 #define IRQ_FREE	-1
+#define IRQ_RESERVED	-2
+#define IRQ_SKIP	-3
 #define GIC_IRQ_START	32
 
-/*
+/**
+ * struct crossbar_device - crossbar device description
  * @int_max: maximum number of supported interrupts
+ * @safe_map: safe default value to initialize the crossbar
+ * @max_crossbar_sources: Maximum number of crossbar sources
  * @irq_map: array of interrupts to crossbar number mapping
  * @crossbar_base: crossbar base address
  * @register_offsets: offsets for each irq number
+ * @write: register write function pointer
  */
 struct crossbar_device {
 	uint int_max;
+	uint safe_map;
+	uint max_crossbar_sources;
 	uint *irq_map;
 	void __iomem *crossbar_base;
 	int *register_offsets;
-	void (*write) (int, int);
+	void (*write)(int, int);
 };
 
 static struct crossbar_device *cb;
@@ -50,11 +59,22 @@ static inline void crossbar_writeb(int irq_no, int cb_no)
 	writeb(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
 }
 
+static inline int get_prev_map_irq(int cb_no)
+{
+	int i;
+
+	for (i = cb->int_max - 1; i >= 0; i--)
+		if (cb->irq_map[i] == cb_no)
+			return i;
+
+	return -ENODEV;
+}
+
 static inline int allocate_free_irq(int cb_no)
 {
 	int i;
 
-	for (i = 0; i < cb->int_max; i++) {
+	for (i = cb->int_max - 1; i >= 0; i--) {
 		if (cb->irq_map[i] == IRQ_FREE) {
 			cb->irq_map[i] = cb_no;
 			return i;
@@ -64,19 +84,47 @@ static inline int allocate_free_irq(int cb_no)
 	return -ENODEV;
 }
 
+static inline bool needs_crossbar_write(irq_hw_number_t hw)
+{
+	int cb_no;
+
+	if (hw > GIC_IRQ_START) {
+		cb_no = cb->irq_map[hw - GIC_IRQ_START];
+		if (cb_no != IRQ_RESERVED && cb_no != IRQ_SKIP)
+			return true;
+	}
+
+	return false;
+}
+
 static int crossbar_domain_map(struct irq_domain *d, unsigned int irq,
 			       irq_hw_number_t hw)
 {
-	cb->write(hw - GIC_IRQ_START, cb->irq_map[hw - GIC_IRQ_START]);
+	if (needs_crossbar_write(hw))
+		cb->write(hw - GIC_IRQ_START, cb->irq_map[hw - GIC_IRQ_START]);
+
 	return 0;
 }
 
+/**
+ * crossbar_domain_unmap - unmap a crossbar<->irq connection
+ * @d: domain of irq to unmap
+ * @irq: virq number
+ *
+ * We do not maintain a use count of total number of map/unmap
+ * calls for a particular irq to find out if a irq can be really
+ * unmapped. This is because unmap is called during irq_dispose_mapping(irq),
+ * after which irq is anyways unusable. So an explicit map has to be called
+ * after that.
+ */
 static void crossbar_domain_unmap(struct irq_domain *d, unsigned int irq)
 {
 	irq_hw_number_t hw = irq_get_irq_data(irq)->hwirq;
 
-	if (hw > GIC_IRQ_START)
+	if (needs_crossbar_write(hw)) {
 		cb->irq_map[hw - GIC_IRQ_START] = IRQ_FREE;
+		cb->write(hw - GIC_IRQ_START, cb->safe_map);
+	}
 }
 
 static int crossbar_domain_xlate(struct irq_domain *d,
@@ -85,18 +133,41 @@ static int crossbar_domain_xlate(struct irq_domain *d,
 				 unsigned long *out_hwirq,
 				 unsigned int *out_type)
 {
-	unsigned long ret;
+	int ret;
+	int req_num = intspec[1];
+	int direct_map_num;
+
+	if (req_num >= cb->max_crossbar_sources) {
+		direct_map_num = req_num - cb->max_crossbar_sources;
+		if (direct_map_num < cb->int_max) {
+			ret = cb->irq_map[direct_map_num];
+			if (ret == IRQ_RESERVED || ret == IRQ_SKIP) {
+				/* We use the interrupt num as h/w irq num */
+				ret = direct_map_num;
+				goto found;
+			}
+		}
+
+		pr_err("%s: requested crossbar number %d > max %d\n",
+		       __func__, req_num, cb->max_crossbar_sources);
+		return -EINVAL;
+	}
 
-	ret = allocate_free_irq(intspec[1]);
+	ret = get_prev_map_irq(req_num);
+	if (ret >= 0)
+		goto found;
 
-	if (IS_ERR_VALUE(ret))
+	ret = allocate_free_irq(req_num);
+
+	if (ret < 0)
 		return ret;
 
+found:
 	*out_hwirq = ret + GIC_IRQ_START;
 	return 0;
 }
 
-const struct irq_domain_ops routable_irq_domain_ops = {
+static const struct irq_domain_ops routable_irq_domain_ops = {
 	.map = crossbar_domain_map,
 	.unmap = crossbar_domain_unmap,
 	.xlate = crossbar_domain_xlate
@@ -104,22 +175,36 @@ const struct irq_domain_ops routable_irq_domain_ops = {
 
 static int __init crossbar_of_init(struct device_node *node)
 {
-	int i, size, max, reserved = 0, entry;
+	int i, size, max = 0, reserved = 0, entry;
 	const __be32 *irqsr;
+	int ret = -ENOMEM;
 
 	cb = kzalloc(sizeof(*cb), GFP_KERNEL);
 
 	if (!cb)
-		return -ENOMEM;
+		return ret;
 
 	cb->crossbar_base = of_iomap(node, 0);
 	if (!cb->crossbar_base)
-		goto err1;
+		goto err_cb;
+
+	of_property_read_u32(node, "ti,max-crossbar-sources",
+			     &cb->max_crossbar_sources);
+	if (!cb->max_crossbar_sources) {
+		pr_err("missing 'ti,max-crossbar-sources' property\n");
+		ret = -EINVAL;
+		goto err_base;
+	}
 
 	of_property_read_u32(node, "ti,max-irqs", &max);
-	cb->irq_map = kzalloc(max * sizeof(int), GFP_KERNEL);
+	if (!max) {
+		pr_err("missing 'ti,max-irqs' property\n");
+		ret = -EINVAL;
+		goto err_base;
+	}
+	cb->irq_map = kcalloc(max, sizeof(int), GFP_KERNEL);
 	if (!cb->irq_map)
-		goto err2;
+		goto err_base;
 
 	cb->int_max = max;
 
@@ -137,15 +222,35 @@ static int __init crossbar_of_init(struct device_node *node)
 						   i, &entry);
 			if (entry > max) {
 				pr_err("Invalid reserved entry\n");
-				goto err3;
+				ret = -EINVAL;
+				goto err_irq_map;
+			}
+			cb->irq_map[entry] = IRQ_RESERVED;
+		}
+	}
+
+	/* Skip irqs hardwired to bypass the crossbar */
+	irqsr = of_get_property(node, "ti,irqs-skip", &size);
+	if (irqsr) {
+		size /= sizeof(__be32);
+
+		for (i = 0; i < size; i++) {
+			of_property_read_u32_index(node,
+						   "ti,irqs-skip",
+						   i, &entry);
+			if (entry > max) {
+				pr_err("Invalid skip entry\n");
+				ret = -EINVAL;
+				goto err_irq_map;
 			}
-			cb->irq_map[entry] = 0;
+			cb->irq_map[entry] = IRQ_SKIP;
 		}
 	}
 
-	cb->register_offsets = kzalloc(max * sizeof(int), GFP_KERNEL);
+
+	cb->register_offsets = kcalloc(max, sizeof(int), GFP_KERNEL);
 	if (!cb->register_offsets)
-		goto err3;
+		goto err_irq_map;
 
 	of_property_read_u32(node, "ti,reg-size", &size);
 
@@ -161,7 +266,8 @@ static int __init crossbar_of_init(struct device_node *node)
 		break;
 	default:
 		pr_err("Invalid reg-size property\n");
-		goto err4;
+		ret = -EINVAL;
+		goto err_reg_offset;
 		break;
 	}
 
@@ -170,25 +276,37 @@ static int __init crossbar_of_init(struct device_node *node)
 	 * reserved irqs. so find and store the offsets once.
 	 */
 	for (i = 0; i < max; i++) {
-		if (!cb->irq_map[i])
+		if (cb->irq_map[i] == IRQ_RESERVED)
 			continue;
 
 		cb->register_offsets[i] = reserved;
 		reserved += size;
 	}
 
+	of_property_read_u32(node, "ti,irqs-safe-map", &cb->safe_map);
+	/* Initialize the crossbar with safe map to start with */
+	for (i = 0; i < max; i++) {
+		if (cb->irq_map[i] == IRQ_RESERVED ||
+		    cb->irq_map[i] == IRQ_SKIP)
+			continue;
+
+		cb->write(i, cb->safe_map);
+	}
+
 	register_routable_domain_ops(&routable_irq_domain_ops);
 	return 0;
 
-err4:
+err_reg_offset:
 	kfree(cb->register_offsets);
-err3:
+err_irq_map:
 	kfree(cb->irq_map);
-err2:
+err_base:
 	iounmap(cb->crossbar_base);
-err1:
+err_cb:
 	kfree(cb);
-	return -ENOMEM;
+
+	cb = NULL;
+	return ret;
 }
 
 static const struct of_device_id crossbar_match[] __initconst = {