/*
   * Copyright (C) 2015 Hisilicon Limited, All Rights Reserved.
   * Author: Jun Ma <majun258@huawei.com>
   * Author: Yun Wu <wuyun.wu@huawei.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.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
   */

  #include <linux/interrupt.h>
  #include <linux/irqchip.h>

  #include <linux/module.h>

  #include <linux/msi.h>

  #include <linux/of_address.h>
  #include <linux/of_irq.h>
  #include <linux/of_platform.h>
  #include <linux/platform_device.h>
  #include <linux/slab.h>

  /* Interrupt numbers per mbigen node supported */
  #define IRQS_PER_MBIGEN_NODE		128
  
  /* 64 irqs (Pin0-pin63) are reserved for each mbigen chip */
  #define RESERVED_IRQ_PER_MBIGEN_CHIP	64
  
  /* The maximum IRQ pin number of mbigen chip(start from 0) */
  #define MAXIMUM_IRQ_PIN_NUM		1407
  
  /**
   * In mbigen vector register
   * bit[21:12]:	event id value
   * bit[11:0]:	device id
   */
  #define IRQ_EVENT_ID_SHIFT		12
  #define IRQ_EVENT_ID_MASK		0x3ff
  
  /* register range of each mbigen node */
  #define MBIGEN_NODE_OFFSET		0x1000
  
  /* offset of vector register in mbigen node */
  #define REG_MBIGEN_VEC_OFFSET		0x200

  /**

   * offset of clear register in mbigen node
   * This register is used to clear the status
   * of interrupt
   */
  #define REG_MBIGEN_CLEAR_OFFSET		0xa000
  
  /**
   * offset of interrupt type register
   * This register is used to configure interrupt
   * trigger type
   */
  #define REG_MBIGEN_TYPE_OFFSET		0x0
  
  /**

   * struct mbigen_device - holds the information of mbigen device.
   *
   * @pdev:		pointer to the platform device structure of mbigen chip.
   * @base:		mapped address of this mbigen chip.
   */
  struct mbigen_device {
  	struct platform_device	*pdev;
  	void __iomem		*base;
  };

  static inline unsigned int get_mbigen_vec_reg(irq_hw_number_t hwirq)
  {
  	unsigned int nid, pin;
  
  	hwirq -= RESERVED_IRQ_PER_MBIGEN_CHIP;
  	nid = hwirq / IRQS_PER_MBIGEN_NODE + 1;
  	pin = hwirq % IRQS_PER_MBIGEN_NODE;
  
  	return pin * 4 + nid * MBIGEN_NODE_OFFSET
  			+ REG_MBIGEN_VEC_OFFSET;
  }

  static inline void get_mbigen_type_reg(irq_hw_number_t hwirq,
  					u32 *mask, u32 *addr)
  {
  	unsigned int nid, irq_ofst, ofst;
  
  	hwirq -= RESERVED_IRQ_PER_MBIGEN_CHIP;
  	nid = hwirq / IRQS_PER_MBIGEN_NODE + 1;
  	irq_ofst = hwirq % IRQS_PER_MBIGEN_NODE;
  
  	*mask = 1 << (irq_ofst % 32);
  	ofst = irq_ofst / 32 * 4;
  
  	*addr = ofst + nid * MBIGEN_NODE_OFFSET
  		+ REG_MBIGEN_TYPE_OFFSET;
  }
  
  static inline void get_mbigen_clear_reg(irq_hw_number_t hwirq,
  					u32 *mask, u32 *addr)
  {
  	unsigned int ofst;
  
  	hwirq -= RESERVED_IRQ_PER_MBIGEN_CHIP;
  	ofst = hwirq / 32 * 4;
  
  	*mask = 1 << (hwirq % 32);
  	*addr = ofst + REG_MBIGEN_CLEAR_OFFSET;
  }
  
  static void mbigen_eoi_irq(struct irq_data *data)
  {
  	void __iomem *base = data->chip_data;
  	u32 mask, addr;
  
  	get_mbigen_clear_reg(data->hwirq, &mask, &addr);
  
  	writel_relaxed(mask, base + addr);
  
  	irq_chip_eoi_parent(data);
  }
  
  static int mbigen_set_type(struct irq_data *data, unsigned int type)
  {
  	void __iomem *base = data->chip_data;
  	u32 mask, addr, val;
  
  	if (type != IRQ_TYPE_LEVEL_HIGH && type != IRQ_TYPE_EDGE_RISING)
  		return -EINVAL;
  
  	get_mbigen_type_reg(data->hwirq, &mask, &addr);
  
  	val = readl_relaxed(base + addr);
  
  	if (type == IRQ_TYPE_LEVEL_HIGH)
  		val |= mask;
  	else
  		val &= ~mask;
  
  	writel_relaxed(val, base + addr);
  
  	return 0;
  }

  static struct irq_chip mbigen_irq_chip = {
  	.name =			"mbigen-v2",

  	.irq_mask =		irq_chip_mask_parent,
  	.irq_unmask =		irq_chip_unmask_parent,
  	.irq_eoi =		mbigen_eoi_irq,
  	.irq_set_type =		mbigen_set_type,
  	.irq_set_affinity =	irq_chip_set_affinity_parent,

  };
  
  static void mbigen_write_msg(struct msi_desc *desc, struct msi_msg *msg)
  {
  	struct irq_data *d = irq_get_irq_data(desc->irq);
  	void __iomem *base = d->chip_data;
  	u32 val;
  
  	base += get_mbigen_vec_reg(d->hwirq);
  	val = readl_relaxed(base);
  
  	val &= ~(IRQ_EVENT_ID_MASK << IRQ_EVENT_ID_SHIFT);
  	val |= (msg->data << IRQ_EVENT_ID_SHIFT);
  
  	/* The address of doorbell is encoded in mbigen register by default
  	 * So,we don't need to program the doorbell address at here
  	 */
  	writel_relaxed(val, base);
  }
  
  static int mbigen_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 != 2)
  			return -EINVAL;
  
  		if ((fwspec->param[0] > MAXIMUM_IRQ_PIN_NUM) ||
  			(fwspec->param[0] < RESERVED_IRQ_PER_MBIGEN_CHIP))
  			return -EINVAL;
  		else
  			*hwirq = fwspec->param[0];
  
  		/* If there is no valid irq type, just use the default type */
  		if ((fwspec->param[1] == IRQ_TYPE_EDGE_RISING) ||
  			(fwspec->param[1] == IRQ_TYPE_LEVEL_HIGH))
  			*type = fwspec->param[1];
  		else
  			return -EINVAL;
  
  		return 0;
  	}
  	return -EINVAL;
  }
  
  static int mbigen_irq_domain_alloc(struct irq_domain *domain,
  					unsigned int virq,
  					unsigned int nr_irqs,
  					void *args)
  {
  	struct irq_fwspec *fwspec = args;
  	irq_hw_number_t hwirq;
  	unsigned int type;
  	struct mbigen_device *mgn_chip;
  	int i, err;
  
  	err = mbigen_domain_translate(domain, fwspec, &hwirq, &type);
  	if (err)
  		return err;
  
  	err = platform_msi_domain_alloc(domain, virq, nr_irqs);
  	if (err)
  		return err;
  
  	mgn_chip = platform_msi_get_host_data(domain);
  
  	for (i = 0; i < nr_irqs; i++)
  		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
  				      &mbigen_irq_chip, mgn_chip->base);
  
  	return 0;
  }
  
  static struct irq_domain_ops mbigen_domain_ops = {
  	.translate	= mbigen_domain_translate,
  	.alloc		= mbigen_irq_domain_alloc,
  	.free		= irq_domain_free_irqs_common,
  };

  static int mbigen_device_probe(struct platform_device *pdev)
  {
  	struct mbigen_device *mgn_chip;

  	struct platform_device *child;

  	struct irq_domain *domain;

  	struct device_node *np;
  	struct device *parent;
  	struct resource *res;

  	u32 num_pins;

  
  	mgn_chip = devm_kzalloc(&pdev->dev, sizeof(*mgn_chip), GFP_KERNEL);
  	if (!mgn_chip)
  		return -ENOMEM;
  
  	mgn_chip->pdev = pdev;
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	mgn_chip->base = devm_ioremap_resource(&pdev->dev, res);
  	if (IS_ERR(mgn_chip->base))
  		return PTR_ERR(mgn_chip->base);

  	for_each_child_of_node(pdev->dev.of_node, np) {
  		if (!of_property_read_bool(np, "interrupt-controller"))
  			continue;

  		parent = platform_bus_type.dev_root;
  		child = of_platform_device_create(np, NULL, parent);

  		if (!child)
  			return -ENOMEM;

  		if (of_property_read_u32(child->dev.of_node, "num-pins",
  					 &num_pins) < 0) {
  			dev_err(&pdev->dev, "No num-pins property
  ");
  			return -EINVAL;
  		}
  
  		domain = platform_msi_create_device_domain(&child->dev, num_pins,
  							   mbigen_write_msg,
  							   &mbigen_domain_ops,
  							   mgn_chip);
  		if (!domain)
  			return -ENOMEM;
  	}

  	platform_set_drvdata(pdev, mgn_chip);

  	return 0;
  }
  
  static const struct of_device_id mbigen_of_match[] = {
  	{ .compatible = "hisilicon,mbigen-v2" },
  	{ /* END */ }
  };
  MODULE_DEVICE_TABLE(of, mbigen_of_match);
  
  static struct platform_driver mbigen_platform_driver = {
  	.driver = {
  		.name		= "Hisilicon MBIGEN-V2",
  		.owner		= THIS_MODULE,
  		.of_match_table	= mbigen_of_match,
  	},
  	.probe			= mbigen_device_probe,
  };
  
  module_platform_driver(mbigen_platform_driver);
  
  MODULE_AUTHOR("Jun Ma <majun258@huawei.com>");
  MODULE_AUTHOR("Yun Wu <wuyun.wu@huawei.com>");
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Hisilicon MBI Generator driver");