drivers/irqchip/irq-crossbar.c - kernel/bruno - Git at Google

 /*
  *  drivers/irqchip/irq-crossbar.c
  *
  *  Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com
  *  Author: Sricharan R <r.sricharan@ti.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  */
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/of_address.h>
 #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);
 };

 static struct crossbar_device *cb;

 static inline void crossbar_writel(int irq_no, int cb_no)
 {
 	writel(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
 }

 static inline void crossbar_writew(int irq_no, int cb_no)
 {
 	writew(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
 }

 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 = cb->int_max - 1; i >= 0; i--) {
 		if (cb->irq_map[i] == IRQ_FREE) {
 			cb->irq_map[i] = cb_no;
 			return i;
 		}
 	}

 	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)
 {
 	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 (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,
 				 struct device_node *controller,
 				 const u32 *intspec, unsigned int intsize,
 				 unsigned long *out_hwirq,
 				 unsigned int *out_type)
 {
 	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 = get_prev_map_irq(req_num);
 	if (ret >= 0)
 		goto found;

 	ret = allocate_free_irq(req_num);

 	if (ret < 0)
 		return ret;

 found:
 	*out_hwirq = ret + GIC_IRQ_START;
 	return 0;
 }

 static const struct irq_domain_ops routable_irq_domain_ops = {
 	.map = crossbar_domain_map,
 	.unmap = crossbar_domain_unmap,
 	.xlate = crossbar_domain_xlate
 };

 static int __init crossbar_of_init(struct device_node *node)
 {
 	int i, size, max = 0, reserved = 0, entry;
 	const __be32 *irqsr;
 	int ret = -ENOMEM;

 	cb = kzalloc(sizeof(*cb), GFP_KERNEL);

 	if (!cb)
 		return ret;

 	cb->crossbar_base = of_iomap(node, 0);
 	if (!cb->crossbar_base)
 		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);
 	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 err_base;

 	cb->int_max = max;

 	for (i = 0; i < max; i++)
 		cb->irq_map[i] = IRQ_FREE;

 	/* Get and mark reserved irqs */
 	irqsr = of_get_property(node, "ti,irqs-reserved", &size);
 	if (irqsr) {
 		size /= sizeof(__be32);

 		for (i = 0; i < size; i++) {
 			of_property_read_u32_index(node,
 						   "ti,irqs-reserved",
 						   i, &entry);
 			if (entry >= max) {
 				pr_err("Invalid reserved entry\n");
 				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] = IRQ_SKIP;
 		}
 	}


 	cb->register_offsets = kcalloc(max, sizeof(int), GFP_KERNEL);
 	if (!cb->register_offsets)
 		goto err_irq_map;

 	of_property_read_u32(node, "ti,reg-size", &size);

 	switch (size) {
 	case 1:
 		cb->write = crossbar_writeb;
 		break;
 	case 2:
 		cb->write = crossbar_writew;
 		break;
 	case 4:
 		cb->write = crossbar_writel;
 		break;
 	default:
 		pr_err("Invalid reg-size property\n");
 		ret = -EINVAL;
 		goto err_reg_offset;
 		break;
 	}

 	/*
 	 * Register offsets are not linear because of the
 	 * reserved irqs. so find and store the offsets once.
 	 */
 	for (i = 0; i < max; 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;

 err_reg_offset:
 	kfree(cb->register_offsets);
 err_irq_map:
 	kfree(cb->irq_map);
 err_base:
 	iounmap(cb->crossbar_base);
 err_cb:
 	kfree(cb);

 	cb = NULL;
 	return ret;
 }

 static const struct of_device_id crossbar_match[] __initconst = {
 	{ .compatible = "ti,irq-crossbar" },
 	{}
 };

 int __init irqcrossbar_init(void)
 {
 	struct device_node *np;
 	np = of_find_matching_node(NULL, crossbar_match);
 	if (!np)
 		return -ENODEV;

 	crossbar_of_init(np);
 	return 0;
 }
	/*
	* drivers/irqchip/irq-crossbar.c
	*
	* Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com
	* Author: Sricharan R <r.sricharan@ti.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	*/
	#include <linux/err.h>
	#include <linux/io.h>
	#include <linux/of_address.h>
	#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);
	};

	static struct crossbar_device *cb;

	static inline void crossbar_writel(int irq_no, int cb_no)
	{
	writel(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
	}

	static inline void crossbar_writew(int irq_no, int cb_no)
	{
	writew(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
	}

	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 = cb->int_max - 1; i >= 0; i--) {
	if (cb->irq_map[i] == IRQ_FREE) {
	cb->irq_map[i] = cb_no;
	return i;
	}
	}

	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)
	{
	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 (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,
	struct device_node *controller,
	const u32 *intspec, unsigned int intsize,
	unsigned long *out_hwirq,
	unsigned int *out_type)
	{
	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 = get_prev_map_irq(req_num);
	if (ret >= 0)
	goto found;

	ret = allocate_free_irq(req_num);

	if (ret < 0)
	return ret;

	found:
	*out_hwirq = ret + GIC_IRQ_START;
	return 0;
	}

	static const struct irq_domain_ops routable_irq_domain_ops = {
	.map = crossbar_domain_map,
	.unmap = crossbar_domain_unmap,
	.xlate = crossbar_domain_xlate
	};

	static int __init crossbar_of_init(struct device_node *node)
	{
	int i, size, max = 0, reserved = 0, entry;
	const __be32 *irqsr;
	int ret = -ENOMEM;

	cb = kzalloc(sizeof(*cb), GFP_KERNEL);

	if (!cb)
	return ret;

	cb->crossbar_base = of_iomap(node, 0);
	if (!cb->crossbar_base)
	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);
	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 err_base;

	cb->int_max = max;

	for (i = 0; i < max; i++)
	cb->irq_map[i] = IRQ_FREE;

	/* Get and mark reserved irqs */
	irqsr = of_get_property(node, "ti,irqs-reserved", &size);
	if (irqsr) {
	size /= sizeof(__be32);

	for (i = 0; i < size; i++) {
	of_property_read_u32_index(node,
	"ti,irqs-reserved",
	i, &entry);
	if (entry >= max) {
	pr_err("Invalid reserved entry\n");
	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] = IRQ_SKIP;
	}
	}


	cb->register_offsets = kcalloc(max, sizeof(int), GFP_KERNEL);
	if (!cb->register_offsets)
	goto err_irq_map;

	of_property_read_u32(node, "ti,reg-size", &size);

	switch (size) {
	case 1:
	cb->write = crossbar_writeb;
	break;
	case 2:
	cb->write = crossbar_writew;
	break;
	case 4:
	cb->write = crossbar_writel;
	break;
	default:
	pr_err("Invalid reg-size property\n");
	ret = -EINVAL;
	goto err_reg_offset;
	break;
	}

	/*
	* Register offsets are not linear because of the
	* reserved irqs. so find and store the offsets once.
	*/
	for (i = 0; i < max; 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;

	err_reg_offset:
	kfree(cb->register_offsets);
	err_irq_map:
	kfree(cb->irq_map);
	err_base:
	iounmap(cb->crossbar_base);
	err_cb:
	kfree(cb);

	cb = NULL;
	return ret;
	}

	static const struct of_device_id crossbar_match[] __initconst = {
	{ .compatible = "ti,irq-crossbar" },
	{}
	};

	int __init irqcrossbar_init(void)
	{
	struct device_node *np;
	np = of_find_matching_node(NULL, crossbar_match);
	if (!np)
	return -ENODEV;

	crossbar_of_init(np);
	return 0;
	}