/*
   * Copyright (c) 2014 MediaTek Inc.
   * Author: Joe.C <yingjoe.chen@mediatek.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.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   */
  
  #include <linux/irq.h>

  #include <linux/irqchip.h>

  #include <linux/irqdomain.h>
  #include <linux/of.h>
  #include <linux/of_irq.h>
  #include <linux/of_address.h>
  #include <linux/io.h>
  #include <linux/slab.h>
  #include <linux/spinlock.h>

  struct mtk_sysirq_chip_data {
  	spinlock_t lock;

  	u32 nr_intpol_bases;
  	void __iomem **intpol_bases;
  	u32 *intpol_words;
  	u8 *intpol_idx;
  	u16 *which_word;

  };
  
  static int mtk_sysirq_set_type(struct irq_data *data, unsigned int type)
  {
  	irq_hw_number_t hwirq = data->hwirq;
  	struct mtk_sysirq_chip_data *chip_data = data->chip_data;

  	u8 intpol_idx = chip_data->intpol_idx[hwirq];
  	void __iomem *base;

  	u32 offset, reg_index, value;
  	unsigned long flags;
  	int ret;

  	base = chip_data->intpol_bases[intpol_idx];
  	reg_index = chip_data->which_word[hwirq];

  	offset = hwirq & 0x1f;

  
  	spin_lock_irqsave(&chip_data->lock, flags);

  	value = readl_relaxed(base + reg_index * 4);

  	if (type == IRQ_TYPE_LEVEL_LOW || type == IRQ_TYPE_EDGE_FALLING) {
  		if (type == IRQ_TYPE_LEVEL_LOW)
  			type = IRQ_TYPE_LEVEL_HIGH;
  		else
  			type = IRQ_TYPE_EDGE_RISING;
  		value |= (1 << offset);
  	} else {
  		value &= ~(1 << offset);
  	}

  	writel_relaxed(value, base + reg_index * 4);

  
  	data = data->parent_data;
  	ret = data->chip->irq_set_type(data, type);
  	spin_unlock_irqrestore(&chip_data->lock, flags);
  	return ret;
  }
  
  static struct irq_chip mtk_sysirq_chip = {
  	.name			= "MT_SYSIRQ",
  	.irq_mask		= irq_chip_mask_parent,
  	.irq_unmask		= irq_chip_unmask_parent,
  	.irq_eoi		= irq_chip_eoi_parent,
  	.irq_set_type		= mtk_sysirq_set_type,
  	.irq_retrigger		= irq_chip_retrigger_hierarchy,
  	.irq_set_affinity	= irq_chip_set_affinity_parent,
  };

  static int mtk_sysirq_domain_translate(struct irq_domain *d,
  				       struct irq_fwspec *fwspec,
  				       unsigned long *hwirq,
  				       unsigned int *type)

  {

  	if (is_of_node(fwspec->fwnode)) {
  		if (fwspec->param_count != 3)
  			return -EINVAL;

  		/* No PPI should point to this domain */
  		if (fwspec->param[0] != 0)
  			return -EINVAL;
  
  		*hwirq = fwspec->param[1];
  		*type = fwspec->param[2] & IRQ_TYPE_SENSE_MASK;
  		return 0;
  	}

  	return -EINVAL;

  }
  
  static int mtk_sysirq_domain_alloc(struct irq_domain *domain, unsigned int virq,
  				   unsigned int nr_irqs, void *arg)
  {
  	int i;
  	irq_hw_number_t hwirq;

  	struct irq_fwspec *fwspec = arg;
  	struct irq_fwspec gic_fwspec = *fwspec;

  	if (fwspec->param_count != 3)

  		return -EINVAL;
  
  	/* sysirq doesn't support PPI */

  	if (fwspec->param[0])

  		return -EINVAL;

  	hwirq = fwspec->param[1];

  	for (i = 0; i < nr_irqs; i++)
  		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
  					      &mtk_sysirq_chip,
  					      domain->host_data);

  	gic_fwspec.fwnode = domain->parent->fwnode;
  	return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, &gic_fwspec);

  }

  static const struct irq_domain_ops sysirq_domain_ops = {

  	.translate	= mtk_sysirq_domain_translate,
  	.alloc		= mtk_sysirq_domain_alloc,
  	.free		= irq_domain_free_irqs_common,

  };
  
  static int __init mtk_sysirq_of_init(struct device_node *node,
  				     struct device_node *parent)
  {
  	struct irq_domain *domain, *domain_parent;
  	struct mtk_sysirq_chip_data *chip_data;

  	int ret, size, intpol_num = 0, nr_intpol_bases = 0, i = 0;

  
  	domain_parent = irq_find_host(parent);
  	if (!domain_parent) {
  		pr_err("mtk_sysirq: interrupt-parent not found
  ");
  		return -EINVAL;
  	}
  
  	chip_data = kzalloc(sizeof(*chip_data), GFP_KERNEL);
  	if (!chip_data)
  		return -ENOMEM;

  	while (of_get_address(node, i++, NULL, NULL))
  		nr_intpol_bases++;
  
  	if (nr_intpol_bases == 0) {
  		pr_err("mtk_sysirq: base address not specified
  ");
  		ret = -EINVAL;
  		goto out_free_chip;
  	}
  
  	chip_data->intpol_words = kcalloc(nr_intpol_bases,
  					  sizeof(*chip_data->intpol_words),
  					  GFP_KERNEL);
  	if (!chip_data->intpol_words) {
  		ret = -ENOMEM;
  		goto out_free_chip;
  	}
  
  	chip_data->intpol_bases = kcalloc(nr_intpol_bases,
  					  sizeof(*chip_data->intpol_bases),
  					  GFP_KERNEL);
  	if (!chip_data->intpol_bases) {
  		ret = -ENOMEM;
  		goto out_free_intpol_words;
  	}
  
  	for (i = 0; i < nr_intpol_bases; i++) {
  		struct resource res;
  
  		ret = of_address_to_resource(node, i, &res);
  		size = resource_size(&res);
  		intpol_num += size * 8;
  		chip_data->intpol_words[i] = size / 4;
  		chip_data->intpol_bases[i] = of_iomap(node, i);
  		if (ret || !chip_data->intpol_bases[i]) {

  			pr_err("%pOF: couldn't map region %d
  ", node, i);

  			ret = -ENODEV;
  			goto out_free_intpol;
  		}
  	}
  
  	chip_data->intpol_idx = kcalloc(intpol_num,
  					sizeof(*chip_data->intpol_idx),
  					GFP_KERNEL);
  	if (!chip_data->intpol_idx) {
  		ret = -ENOMEM;
  		goto out_free_intpol;
  	}
  
  	chip_data->which_word = kcalloc(intpol_num,
  					sizeof(*chip_data->which_word),
  					GFP_KERNEL);
  	if (!chip_data->which_word) {
  		ret = -ENOMEM;
  		goto out_free_intpol_idx;
  	}
  
  	/*
  	 * assign an index of the intpol_bases for each irq
  	 * to set it fast later
  	 */
  	for (i = 0; i < intpol_num ; i++) {
  		u32 word = i / 32, j;
  
  		for (j = 0; word >= chip_data->intpol_words[j] ; j++)
  			word -= chip_data->intpol_words[j];
  
  		chip_data->intpol_idx[i] = j;
  		chip_data->which_word[i] = word;

  	}

  	domain = irq_domain_add_hierarchy(domain_parent, 0, intpol_num, node,

  					  &sysirq_domain_ops, chip_data);
  	if (!domain) {
  		ret = -ENOMEM;

  		goto out_free_which_word;

  	}
  	spin_lock_init(&chip_data->lock);
  
  	return 0;

  out_free_which_word:
  	kfree(chip_data->which_word);
  out_free_intpol_idx:
  	kfree(chip_data->intpol_idx);
  out_free_intpol:
  	for (i = 0; i < nr_intpol_bases; i++)
  		if (chip_data->intpol_bases[i])
  			iounmap(chip_data->intpol_bases[i]);
  	kfree(chip_data->intpol_bases);
  out_free_intpol_words:
  	kfree(chip_data->intpol_words);
  out_free_chip:

  	kfree(chip_data);
  	return ret;
  }
  IRQCHIP_DECLARE(mtk_sysirq, "mediatek,mt6577-sysirq", mtk_sysirq_of_init);