// SPDX-License-Identifier: GPL-2.0-only

  #include <linux/cpumask.h>

  #include <linux/kernel.h>
  #include <linux/string.h>
  #include <linux/errno.h>

  #include <linux/msi.h>

  #include <linux/irq.h>
  #include <linux/pci.h>

  #include <linux/irqdomain.h>

  
  #include <asm/hw_irq.h>
  #include <asm/irq_remapping.h>

  #include <asm/processor.h>
  #include <asm/x86_init.h>
  #include <asm/apic.h>

  #include <asm/hpet.h>

  #include "irq_remapping.h"

  int irq_remapping_enabled;

  int irq_remap_broken;

  int disable_sourceid_checking;
  int no_x2apic_optout;

  int disable_irq_post = 0;

  static int disable_irq_remap;

  static struct irq_remap_ops *remap_ops;

  static void irq_remapping_restore_boot_irq_mode(void)

  {
  	/*
  	 * With interrupt-remapping, for now we will use virtual wire A
  	 * mode, as virtual wire B is little complex (need to configure
  	 * both IOAPIC RTE as well as interrupt-remapping table entry).
  	 * As this gets called during crash dump, keep this simple for
  	 * now.
  	 */

  	if (boot_cpu_has(X86_FEATURE_APIC) || apic_from_smp_config())

  		disconnect_bsp_APIC(0);
  }
  
  static void __init irq_remapping_modify_x86_ops(void)
  {

  	x86_apic_ops.restore = irq_remapping_restore_boot_irq_mode;

  }

  static __init int setup_nointremap(char *str)
  {

  	disable_irq_remap = 1;

  	return 0;
  }
  early_param("nointremap", setup_nointremap);

  static __init int setup_irqremap(char *str)

  {
  	if (!str)
  		return -EINVAL;
  
  	while (*str) {

  		if (!strncmp(str, "on", 2)) {

  			disable_irq_remap = 0;

  			disable_irq_post = 0;
  		} else if (!strncmp(str, "off", 3)) {

  			disable_irq_remap = 1;

  			disable_irq_post = 1;
  		} else if (!strncmp(str, "nosid", 5))

  			disable_sourceid_checking = 1;
  		else if (!strncmp(str, "no_x2apic_optout", 16))
  			no_x2apic_optout = 1;

  		else if (!strncmp(str, "nopost", 6))
  			disable_irq_post = 1;

  
  		str += strcspn(str, ",");
  		while (*str == ',')
  			str++;
  	}
  
  	return 0;
  }

  early_param("intremap", setup_irqremap);

  void set_irq_remapping_broken(void)
  {
  	irq_remap_broken = 1;
  }

  bool irq_remapping_cap(enum irq_remap_cap cap)
  {
  	if (!remap_ops || disable_irq_post)

  		return false;

  
  	return (remap_ops->capability & (1 << cap));
  }
  EXPORT_SYMBOL_GPL(irq_remapping_cap);

  int __init irq_remapping_prepare(void)

  {

  	if (disable_irq_remap)

  		return -ENOSYS;

  	if (intel_irq_remap_ops.prepare() == 0)
  		remap_ops = &intel_irq_remap_ops;
  	else if (IS_ENABLED(CONFIG_AMD_IOMMU) &&
  		 amd_iommu_irq_ops.prepare() == 0)

  		remap_ops = &amd_iommu_irq_ops;

  	else if (IS_ENABLED(CONFIG_HYPERV_IOMMU) &&
  		 hyperv_irq_remap_ops.prepare() == 0)
  		remap_ops = &hyperv_irq_remap_ops;

  	else
  		return -ENOSYS;
  
  	return 0;

  }

  int __init irq_remapping_enable(void)

  {

  	int ret;

  	if (!remap_ops->enable)

  		return -ENODEV;

  	ret = remap_ops->enable();
  
  	if (irq_remapping_enabled)
  		irq_remapping_modify_x86_ops();
  
  	return ret;

  }

  void irq_remapping_disable(void)

  {

  	if (irq_remapping_enabled && remap_ops->disable)
  		remap_ops->disable();

  }

  int irq_remapping_reenable(int mode)

  {

  	if (irq_remapping_enabled && remap_ops->reenable)
  		return remap_ops->reenable(mode);

  	return 0;

  }

  int __init irq_remap_enable_fault_handling(void)

  {

  	if (!irq_remapping_enabled)
  		return 0;

  	if (!remap_ops->enable_faulting)

  		return -ENODEV;
  
  	return remap_ops->enable_faulting();
  }

  void panic_if_irq_remap(const char *msg)
  {
  	if (irq_remapping_enabled)
  		panic(msg);
  }

  /**

   * irq_remapping_get_irq_domain - Get the irqdomain serving the request @info
   * @info: interrupt allocation information, used to identify the IOMMU device
   *

   * Returns pointer to IRQ domain, or NULL on failure.
   */

  struct irq_domain *irq_remapping_get_irq_domain(struct irq_alloc_info *info)

  {
  	if (!remap_ops || !remap_ops->get_irq_domain)
  		return NULL;
  
  	return remap_ops->get_irq_domain(info);
  }