/*
   *  pci_irq.c - ACPI PCI Interrupt Routing ($Revision: 11 $)
   *
   *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   *  Copyright (C) 2002       Dominik Brodowski <devel@brodo.de>
   *  (c) Copyright 2008 Hewlett-Packard Development Company, L.P.
   *	Bjorn Helgaas <bjorn.helgaas@hp.com>
   *
   * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   *
   *  This program is free software; you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License as published by
   *  the Free Software Foundation; either version 2 of the License, or (at
   *  your option) any later version.
   *
   *  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, write to the Free Software Foundation, Inc.,
   *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
   *
   * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   */
  
  
  #include <linux/dmi.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/types.h>
  #include <linux/spinlock.h>
  #include <linux/pm.h>
  #include <linux/pci.h>
  #include <linux/acpi.h>
  #include <linux/slab.h>
  
  #define PREFIX "ACPI: "
  
  #define _COMPONENT		ACPI_PCI_COMPONENT
  ACPI_MODULE_NAME("pci_irq");
  
  struct acpi_prt_entry {
  	struct list_head	list;
  	struct acpi_pci_id	id;
  	u8			pin;
  	acpi_handle		link;
  	u32			index;		/* GSI, or link _CRS index */
  };
  
  static inline char pin_name(int pin)
  {
  	return 'A' + pin - 1;
  }
  
  /* --------------------------------------------------------------------------
                           PCI IRQ Routing Table (PRT) Support
     -------------------------------------------------------------------------- */
  
  /* http://bugzilla.kernel.org/show_bug.cgi?id=4773 */
  static const struct dmi_system_id medion_md9580[] = {
  	{
  		.ident = "Medion MD9580-F laptop",
  		.matches = {
  			DMI_MATCH(DMI_SYS_VENDOR, "MEDIONNB"),
  			DMI_MATCH(DMI_PRODUCT_NAME, "A555"),
  		},
  	},
  	{ }
  };
  
  /* http://bugzilla.kernel.org/show_bug.cgi?id=5044 */
  static const struct dmi_system_id dell_optiplex[] = {
  	{
  		.ident = "Dell Optiplex GX1",
  		.matches = {
  			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
  			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex GX1 600S+"),
  		},
  	},
  	{ }
  };
  
  /* http://bugzilla.kernel.org/show_bug.cgi?id=10138 */
  static const struct dmi_system_id hp_t5710[] = {
  	{
  		.ident = "HP t5710",
  		.matches = {
  			DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
  			DMI_MATCH(DMI_PRODUCT_NAME, "hp t5000 series"),
  			DMI_MATCH(DMI_BOARD_NAME, "098Ch"),
  		},
  	},
  	{ }
  };
  
  struct prt_quirk {
  	const struct dmi_system_id *system;
  	unsigned int		segment;
  	unsigned int		bus;
  	unsigned int		device;
  	unsigned char		pin;
  	const char		*source;	/* according to BIOS */
  	const char		*actual_source;
  };
  
  #define PCI_INTX_PIN(c)		(c - 'A' + 1)
  
  /*
   * These systems have incorrect _PRT entries.  The BIOS claims the PCI
   * interrupt at the listed segment/bus/device/pin is connected to the first
   * link device, but it is actually connected to the second.
   */
  static const struct prt_quirk prt_quirks[] = {
  	{ medion_md9580, 0, 0, 9, PCI_INTX_PIN('A'),
  		"\\_SB_.PCI0.ISA_.LNKA",
  		"\\_SB_.PCI0.ISA_.LNKB"},
  	{ dell_optiplex, 0, 0, 0xd, PCI_INTX_PIN('A'),
  		"\\_SB_.LNKB",
  		"\\_SB_.LNKA"},
  	{ hp_t5710, 0, 0, 1, PCI_INTX_PIN('A'),
  		"\\_SB_.PCI0.LNK1",
  		"\\_SB_.PCI0.LNK3"},
  };
  
  static void do_prt_fixups(struct acpi_prt_entry *entry,
  			  struct acpi_pci_routing_table *prt)
  {
  	int i;
  	const struct prt_quirk *quirk;
  
  	for (i = 0; i < ARRAY_SIZE(prt_quirks); i++) {
  		quirk = &prt_quirks[i];
  
  		/* All current quirks involve link devices, not GSIs */
  		if (!prt->source)
  			continue;
  
  		if (dmi_check_system(quirk->system) &&
  		    entry->id.segment == quirk->segment &&
  		    entry->id.bus == quirk->bus &&
  		    entry->id.device == quirk->device &&
  		    entry->pin == quirk->pin &&
  		    !strcmp(prt->source, quirk->source) &&
  		    strlen(prt->source) >= strlen(quirk->actual_source)) {
  			printk(KERN_WARNING PREFIX "firmware reports "
  				"%04x:%02x:%02x PCI INT %c connected to %s; "
  				"changing to %s
  ",
  				entry->id.segment, entry->id.bus,
  				entry->id.device, pin_name(entry->pin),
  				prt->source, quirk->actual_source);
  			strcpy(prt->source, quirk->actual_source);
  		}
  	}
  }
  
  static int acpi_pci_irq_check_entry(acpi_handle handle, struct pci_dev *dev,
  				  int pin, struct acpi_pci_routing_table *prt,
  				  struct acpi_prt_entry **entry_ptr)
  {
  	int segment = pci_domain_nr(dev->bus);
  	int bus = dev->bus->number;
  	int device = PCI_SLOT(dev->devfn);
  	struct acpi_prt_entry *entry;
  
  	if (((prt->address >> 16) & 0xffff) != device ||
  	    prt->pin + 1 != pin)
  		return -ENODEV;
  
  	entry = kzalloc(sizeof(struct acpi_prt_entry), GFP_KERNEL);
  	if (!entry)
  		return -ENOMEM;
  
  	/*
  	 * Note that the _PRT uses 0=INTA, 1=INTB, etc, while PCI uses
  	 * 1=INTA, 2=INTB.  We use the PCI encoding throughout, so convert
  	 * it here.
  	 */
  	entry->id.segment = segment;
  	entry->id.bus = bus;
  	entry->id.device = (prt->address >> 16) & 0xFFFF;
  	entry->pin = prt->pin + 1;
  
  	do_prt_fixups(entry, prt);
  
  	entry->index = prt->source_index;
  
  	/*
  	 * Type 1: Dynamic
  	 * ---------------
  	 * The 'source' field specifies the PCI interrupt link device used to
  	 * configure the IRQ assigned to this slot|dev|pin.  The 'source_index'
  	 * indicates which resource descriptor in the resource template (of
  	 * the link device) this interrupt is allocated from.
  	 * 
  	 * NOTE: Don't query the Link Device for IRQ information at this time
  	 *       because Link Device enumeration may not have occurred yet
  	 *       (e.g. exists somewhere 'below' this _PRT entry in the ACPI
  	 *       namespace).
  	 */
  	if (prt->source[0])
  		acpi_get_handle(handle, prt->source, &entry->link);
  
  	/*
  	 * Type 2: Static
  	 * --------------
  	 * The 'source' field is NULL, and the 'source_index' field specifies
  	 * the IRQ value, which is hardwired to specific interrupt inputs on
  	 * the interrupt controller.
  	 */
  
  	ACPI_DEBUG_PRINT_RAW((ACPI_DB_INFO,
  			      "      %04x:%02x:%02x[%c] -> %s[%d]
  ",
  			      entry->id.segment, entry->id.bus,
  			      entry->id.device, pin_name(entry->pin),
  			      prt->source, entry->index));
  
  	*entry_ptr = entry;
  
  	return 0;
  }
  
  static int acpi_pci_irq_find_prt_entry(struct pci_dev *dev,
  			  int pin, struct acpi_prt_entry **entry_ptr)
  {
  	acpi_status status;
  	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
  	struct acpi_pci_routing_table *entry;
  	acpi_handle handle = NULL;
  
  	if (dev->bus->bridge)
  		handle = ACPI_HANDLE(dev->bus->bridge);
  
  	if (!handle)
  		return -ENODEV;
  
  	/* 'handle' is the _PRT's parent (root bridge or PCI-PCI bridge) */
  	status = acpi_get_irq_routing_table(handle, &buffer);
  	if (ACPI_FAILURE(status)) {
  		kfree(buffer.pointer);
  		return -ENODEV;
  	}
  
  	entry = buffer.pointer;
  	while (entry && (entry->length > 0)) {
  		if (!acpi_pci_irq_check_entry(handle, dev, pin,
  						 entry, entry_ptr))
  			break;
  		entry = (struct acpi_pci_routing_table *)
  		    ((unsigned long)entry + entry->length);
  	}
  
  	kfree(buffer.pointer);
  	return 0;
  }
  
  /* --------------------------------------------------------------------------
                            PCI Interrupt Routing Support
     -------------------------------------------------------------------------- */
  #ifdef CONFIG_X86_IO_APIC
  extern int noioapicquirk;
  extern int noioapicreroute;
  
  static int bridge_has_boot_interrupt_variant(struct pci_bus *bus)
  {
  	struct pci_bus *bus_it;
  
  	for (bus_it = bus ; bus_it ; bus_it = bus_it->parent) {
  		if (!bus_it->self)
  			return 0;
  		if (bus_it->self->irq_reroute_variant)
  			return bus_it->self->irq_reroute_variant;
  	}
  	return 0;
  }
  
  /*
   * Some chipsets (e.g. Intel 6700PXH) generate a legacy INTx when the IRQ
   * entry in the chipset's IO-APIC is masked (as, e.g. the RT kernel does
   * during interrupt handling). When this INTx generation cannot be disabled,
   * we reroute these interrupts to their legacy equivalent to get rid of
   * spurious interrupts.
   */
  static int acpi_reroute_boot_interrupt(struct pci_dev *dev,
  				       struct acpi_prt_entry *entry)
  {
  	if (noioapicquirk || noioapicreroute) {
  		return 0;
  	} else {
  		switch (bridge_has_boot_interrupt_variant(dev->bus)) {
  		case 0:
  			/* no rerouting necessary */
  			return 0;
  		case INTEL_IRQ_REROUTE_VARIANT:
  			/*
  			 * Remap according to INTx routing table in 6700PXH
  			 * specs, intel order number 302628-002, section
  			 * 2.15.2. Other chipsets (80332, ...) have the same
  			 * mapping and are handled here as well.
  			 */
  			dev_info(&dev->dev, "PCI IRQ %d -> rerouted to legacy "
  				 "IRQ %d
  ", entry->index,
  				 (entry->index % 4) + 16);
  			entry->index = (entry->index % 4) + 16;
  			return 1;
  		default:
  			dev_warn(&dev->dev, "Cannot reroute IRQ %d to legacy "
  				 "IRQ: unknown mapping
  ", entry->index);
  			return -1;
  		}
  	}
  }
  #endif /* CONFIG_X86_IO_APIC */
  
  static struct acpi_prt_entry *acpi_pci_irq_lookup(struct pci_dev *dev, int pin)
  {
  	struct acpi_prt_entry *entry = NULL;
  	struct pci_dev *bridge;
  	u8 bridge_pin, orig_pin = pin;
  	int ret;
  
  	ret = acpi_pci_irq_find_prt_entry(dev, pin, &entry);
  	if (!ret && entry) {
  #ifdef CONFIG_X86_IO_APIC
  		acpi_reroute_boot_interrupt(dev, entry);
  #endif /* CONFIG_X86_IO_APIC */
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %s[%c] _PRT entry
  ",
  				  pci_name(dev), pin_name(pin)));
  		return entry;
  	}
  
  	/*
  	 * Attempt to derive an IRQ for this device from a parent bridge's
  	 * PCI interrupt routing entry (eg. yenta bridge and add-in card bridge).
  	 */
  	bridge = dev->bus->self;
  	while (bridge) {
  		pin = pci_swizzle_interrupt_pin(dev, pin);
  
  		if ((bridge->class >> 8) == PCI_CLASS_BRIDGE_CARDBUS) {
  			/* PC card has the same IRQ as its cardbridge */
  			bridge_pin = bridge->pin;
  			if (!bridge_pin) {
  				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  						  "No interrupt pin configured for device %s
  ",
  						  pci_name(bridge)));
  				return NULL;
  			}
  			pin = bridge_pin;
  		}
  
  		ret = acpi_pci_irq_find_prt_entry(bridge, pin, &entry);
  		if (!ret && entry) {
  			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  					 "Derived GSI for %s INT %c from %s
  ",
  					 pci_name(dev), pin_name(orig_pin),
  					 pci_name(bridge)));
  			return entry;
  		}
  
  		dev = bridge;
  		bridge = dev->bus->self;
  	}
  
  	dev_warn(&dev->dev, "can't derive routing for PCI INT %c
  ",
  		 pin_name(orig_pin));
  	return NULL;
  }
  
  int acpi_pci_irq_enable(struct pci_dev *dev)
  {
  	struct acpi_prt_entry *entry;
  	int gsi;
  	u8 pin;
  	int triggering = ACPI_LEVEL_SENSITIVE;
  	int polarity = ACPI_ACTIVE_LOW;
  	char *link = NULL;
  	char link_desc[16];
  	int rc;
  
  	pin = dev->pin;
  	if (!pin) {
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  				  "No interrupt pin configured for device %s
  ",
  				  pci_name(dev)));
  		return 0;
  	}
  
  	entry = acpi_pci_irq_lookup(dev, pin);
  	if (!entry) {
  		/*
  		 * IDE legacy mode controller IRQs are magic. Why do compat
  		 * extensions always make such a nasty mess.
  		 */
  		if (dev->class >> 8 == PCI_CLASS_STORAGE_IDE &&
  				(dev->class & 0x05) == 0)
  			return 0;
  	}
  
  	if (entry) {
  		if (entry->link)
  			gsi = acpi_pci_link_allocate_irq(entry->link,
  							 entry->index,
  							 &triggering, &polarity,
  							 &link);
  		else
  			gsi = entry->index;
  	} else
  		gsi = -1;
  
  	/*
  	 * No IRQ known to the ACPI subsystem - maybe the BIOS / 
  	 * driver reported one, then use it. Exit in any case.
  	 */
  	if (gsi < 0) {
  		u32 dev_gsi;
  		/* Interrupt Line values above 0xF are forbidden */
  		if (dev->irq > 0 && (dev->irq <= 0xF) &&
  		    (acpi_isa_irq_to_gsi(dev->irq, &dev_gsi) == 0)) {
  			dev_warn(&dev->dev, "PCI INT %c: no GSI - using ISA IRQ %d
  ",
  				 pin_name(pin), dev->irq);
  			acpi_register_gsi(&dev->dev, dev_gsi,
  					  ACPI_LEVEL_SENSITIVE,
  					  ACPI_ACTIVE_LOW);
  		} else {
  			dev_warn(&dev->dev, "PCI INT %c: no GSI
  ",
  				 pin_name(pin));
  		}
  
  		kfree(entry);
  		return 0;
  	}
  
  	rc = acpi_register_gsi(&dev->dev, gsi, triggering, polarity);
  	if (rc < 0) {
  		dev_warn(&dev->dev, "PCI INT %c: failed to register GSI
  ",
  			 pin_name(pin));
  		kfree(entry);
  		return rc;
  	}
  	dev->irq = rc;
  
  	if (link)
  		snprintf(link_desc, sizeof(link_desc), " -> Link[%s]", link);
  	else
  		link_desc[0] = '\0';
  
  	dev_dbg(&dev->dev, "PCI INT %c%s -> GSI %u (%s, %s) -> IRQ %d
  ",
  		pin_name(pin), link_desc, gsi,
  		(triggering == ACPI_LEVEL_SENSITIVE) ? "level" : "edge",
  		(polarity == ACPI_ACTIVE_LOW) ? "low" : "high", dev->irq);
  
  	kfree(entry);
  	return 0;
  }
  
  void acpi_pci_irq_disable(struct pci_dev *dev)
  {
  	struct acpi_prt_entry *entry;
  	int gsi;
  	u8 pin;
  
  	pin = dev->pin;
  	if (!pin)
  		return;
  
  	entry = acpi_pci_irq_lookup(dev, pin);
  	if (!entry)
  		return;
  
  	if (entry->link)
  		gsi = acpi_pci_link_free_irq(entry->link);
  	else
  		gsi = entry->index;
  
  	kfree(entry);
  
  	/*
  	 * TBD: It might be worth clearing dev->irq by magic constant
  	 * (e.g. PCI_UNDEFINED_IRQ).
  	 */
  
  	dev_dbg(&dev->dev, "PCI INT %c disabled
  ", pin_name(pin));
  	acpi_unregister_gsi(gsi);
  }