/*
   * Copyright (C) 2013-2015 ARM Limited, All Rights Reserved.
   * Author: Marc Zyngier <marc.zyngier@arm.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/acpi_iort.h>

  #include <linux/msi.h>
  #include <linux/of.h>
  #include <linux/of_irq.h>
  #include <linux/of_pci.h>

  static void its_mask_msi_irq(struct irq_data *d)
  {
  	pci_msi_mask_irq(d);
  	irq_chip_mask_parent(d);
  }
  
  static void its_unmask_msi_irq(struct irq_data *d)
  {
  	pci_msi_unmask_irq(d);
  	irq_chip_unmask_parent(d);
  }
  
  static struct irq_chip its_msi_irq_chip = {
  	.name			= "ITS-MSI",
  	.irq_unmask		= its_unmask_msi_irq,
  	.irq_mask		= its_mask_msi_irq,
  	.irq_eoi		= irq_chip_eoi_parent,
  	.irq_write_msi_msg	= pci_msi_domain_write_msg,
  };
  
  struct its_pci_alias {
  	struct pci_dev	*pdev;

  	u32		count;
  };
  
  static int its_pci_msi_vec_count(struct pci_dev *pdev)
  {
  	int msi, msix;
  
  	msi = max(pci_msi_vec_count(pdev), 0);
  	msix = max(pci_msix_vec_count(pdev), 0);
  
  	return max(msi, msix);
  }
  
  static int its_get_pci_alias(struct pci_dev *pdev, u16 alias, void *data)
  {
  	struct its_pci_alias *dev_alias = data;

  	if (pdev != dev_alias->pdev)

  		dev_alias->count += its_pci_msi_vec_count(pdev);

  
  	return 0;
  }
  
  static int its_pci_msi_prepare(struct irq_domain *domain, struct device *dev,
  			       int nvec, msi_alloc_info_t *info)
  {
  	struct pci_dev *pdev;
  	struct its_pci_alias dev_alias;

  	struct msi_domain_info *msi_info;

  
  	if (!dev_is_pci(dev))
  		return -EINVAL;

  	msi_info = msi_get_domain_info(domain->parent);

  	pdev = to_pci_dev(dev);
  	dev_alias.pdev = pdev;
  	dev_alias.count = nvec;
  
  	pci_for_each_dma_alias(pdev, its_get_pci_alias, &dev_alias);

  	/* ITS specific DeviceID, as the core ITS ignores dev. */

  	info->scratchpad[0].ul = pci_msi_domain_get_msi_rid(domain, pdev);

  
  	return msi_info->ops->msi_prepare(domain->parent,
  					  dev, dev_alias.count, info);

  }
  
  static struct msi_domain_ops its_pci_msi_ops = {
  	.msi_prepare	= its_pci_msi_prepare,
  };
  
  static struct msi_domain_info its_pci_msi_domain_info = {
  	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
  		   MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
  	.ops	= &its_pci_msi_ops,
  	.chip	= &its_msi_irq_chip,
  };

  static struct of_device_id its_device_id[] = {
  	{	.compatible	= "arm,gic-v3-its",	},
  	{},
  };

  static int __init its_pci_msi_init_one(struct fwnode_handle *handle,
  				       const char *name)

  {

  	struct irq_domain *parent;

  	parent = irq_find_matching_fwnode(handle, DOMAIN_BUS_NEXUS);
  	if (!parent || !msi_get_domain_info(parent)) {
  		pr_err("%s: Unable to locate ITS domain
  ", name);
  		return -ENXIO;
  	}
  
  	if (!pci_msi_create_irq_domain(handle, &its_pci_msi_domain_info,
  				       parent)) {
  		pr_err("%s: Unable to create PCI domain
  ", name);
  		return -ENOMEM;
  	}
  
  	return 0;
  }
  
  static int __init its_pci_of_msi_init(void)
  {
  	struct device_node *np;

  	for (np = of_find_matching_node(NULL, its_device_id); np;
  	     np = of_find_matching_node(np, its_device_id)) {
  		if (!of_property_read_bool(np, "msi-controller"))
  			continue;

  		if (its_pci_msi_init_one(of_node_to_fwnode(np), np->full_name))

  			continue;

  
  		pr_info("PCI/MSI: %s domain created
  ", np->full_name);
  	}
  
  	return 0;

  }

  #ifdef CONFIG_ACPI
  
  static int __init
  its_pci_msi_parse_madt(struct acpi_subtable_header *header,
  		       const unsigned long end)
  {
  	struct acpi_madt_generic_translator *its_entry;
  	struct fwnode_handle *dom_handle;
  	const char *node_name;
  	int err = -ENXIO;
  
  	its_entry = (struct acpi_madt_generic_translator *)header;
  	node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx",
  			      (long)its_entry->base_address);
  	dom_handle = iort_find_domain_token(its_entry->translation_id);
  	if (!dom_handle) {
  		pr_err("%s: Unable to locate ITS domain handle
  ", node_name);
  		goto out;
  	}
  
  	err = its_pci_msi_init_one(dom_handle, node_name);
  	if (!err)
  		pr_info("PCI/MSI: %s domain created
  ", node_name);
  
  out:
  	kfree(node_name);
  	return err;
  }
  
  static int __init its_pci_acpi_msi_init(void)
  {
  	acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
  			      its_pci_msi_parse_madt, 0);
  	return 0;
  }
  #else
  static int __init its_pci_acpi_msi_init(void)
  {
  	return 0;
  }
  #endif

  static int __init its_pci_msi_init(void)
  {
  	its_pci_of_msi_init();

  	its_pci_acpi_msi_init();

  
  	return 0;
  }

  early_initcall(its_pci_msi_init);