/*
  ** I/O Sapic Driver - PCI interrupt line support
  **
  **      (c) Copyright 1999 Grant Grundler
  **      (c) Copyright 1999 Hewlett-Packard Company
  **
  **      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.
  **
  ** The I/O sapic driver manages the Interrupt Redirection Table which is
  ** the control logic to convert PCI line based interrupts into a Message
  ** Signaled Interrupt (aka Transaction Based Interrupt, TBI).
  **
  ** Acronyms
  ** --------
  ** HPA  Hard Physical Address (aka MMIO address)
  ** IRQ  Interrupt ReQuest. Implies Line based interrupt.
  ** IRT	Interrupt Routing Table (provided by PAT firmware)
  ** IRdT Interrupt Redirection Table. IRQ line to TXN ADDR/DATA
  **      table which is implemented in I/O SAPIC.
  ** ISR  Interrupt Service Routine. aka Interrupt handler.
  ** MSI	Message Signaled Interrupt. PCI 2.2 functionality.
  **      aka Transaction Based Interrupt (or TBI).
  ** PA   Precision Architecture. HP's RISC architecture.
  ** RISC Reduced Instruction Set Computer.
  **
  **
  ** What's a Message Signalled Interrupt?
  ** -------------------------------------
  ** MSI is a write transaction which targets a processor and is similar
  ** to a processor write to memory or MMIO. MSIs can be generated by I/O
  ** devices as well as processors and require *architecture* to work.
  **
  ** PA only supports MSI. So I/O subsystems must either natively generate
  ** MSIs (e.g. GSC or HP-PB) or convert line based interrupts into MSIs
  ** (e.g. PCI and EISA).  IA64 supports MSIs via a "local SAPIC" which
  ** acts on behalf of a processor.
  **
  ** MSI allows any I/O device to interrupt any processor. This makes
  ** load balancing of the interrupt processing possible on an SMP platform.
  ** Interrupts are also ordered WRT to DMA data.  It's possible on I/O
  ** coherent systems to completely eliminate PIO reads from the interrupt
  ** path. The device and driver must be designed and implemented to
  ** guarantee all DMA has been issued (issues about atomicity here)
  ** before the MSI is issued. I/O status can then safely be read from
  ** DMA'd data by the ISR.
  **
  **
  ** PA Firmware
  ** -----------

  ** PA-RISC platforms have two fundamentally different types of firmware.

  ** For PCI devices, "Legacy" PDC initializes the "INTERRUPT_LINE" register
  ** and BARs similar to a traditional PC BIOS.
  ** The newer "PAT" firmware supports PDC calls which return tables.

  ** PAT firmware only initializes the PCI Console and Boot interface.
  ** With these tables, the OS can program all other PCI devices.

  **
  ** One such PAT PDC call returns the "Interrupt Routing Table" (IRT).
  ** The IRT maps each PCI slot's INTA-D "output" line to an I/O SAPIC
  ** input line.  If the IRT is not available, this driver assumes
  ** INTERRUPT_LINE register has been programmed by firmware. The latter
  ** case also means online addition of PCI cards can NOT be supported
  ** even if HW support is present.
  **
  ** All platforms with PAT firmware to date (Oct 1999) use one Interrupt
  ** Routing Table for the entire platform.
  **
  ** Where's the iosapic?
  ** --------------------
  ** I/O sapic is part of the "Core Electronics Complex". And on HP platforms
  ** it's integrated as part of the PCI bus adapter, "lba".  So no bus walk
  ** will discover I/O Sapic. I/O Sapic driver learns about each device
  ** when lba driver advertises the presence of the I/O sapic by calling
  ** iosapic_register().
  **
  **
  ** IRQ handling notes
  ** ------------------
  ** The IO-SAPIC can indicate to the CPU which interrupt was asserted.
  ** So, unlike the GSC-ASIC and Dino, we allocate one CPU interrupt per
  ** IO-SAPIC interrupt and call the device driver's handler directly.
  ** The IO-SAPIC driver hijacks the CPU interrupt handler so it can
  ** issue the End Of Interrupt command to the IO-SAPIC.
  **
  ** Overview of exported iosapic functions
  ** --------------------------------------
  ** (caveat: code isn't finished yet - this is just the plan)
  **
  ** iosapic_init:
  **   o initialize globals (lock, etc)
  **   o try to read IRT. Presence of IRT determines if this is
  **     a PAT platform or not.
  **
  ** iosapic_register():
  **   o create iosapic_info instance data structure
  **   o allocate vector_info array for this iosapic
  **   o initialize vector_info - read corresponding IRdT?
  **
  ** iosapic_xlate_pin: (only called by fixup_irq for PAT platform)
  **   o intr_pin = read cfg (INTERRUPT_PIN);
  **   o if (device under PCI-PCI bridge)
  **               translate slot/pin
  **
  ** iosapic_fixup_irq:
  **   o if PAT platform (IRT present)
  **	   intr_pin = iosapic_xlate_pin(isi,pcidev):
  **         intr_line = find IRT entry(isi, PCI_SLOT(pcidev), intr_pin)
  **         save IRT entry into vector_info later
  **         write cfg INTERRUPT_LINE (with intr_line)?
  **     else
  **         intr_line = pcidev->irq
  **         IRT pointer = NULL
  **     endif
  **   o locate vector_info (needs: isi, intr_line)
  **   o allocate processor "irq" and get txn_addr/data
  **   o request_irq(processor_irq,  iosapic_interrupt, vector_info,...)
  **
  ** iosapic_enable_irq:
  **   o clear any pending IRQ on that line
  **   o enable IRdT - call enable_irq(vector[line]->processor_irq)
  **   o write EOI in case line is already asserted.
  **
  ** iosapic_disable_irq:
  **   o disable IRdT - call disable_irq(vector[line]->processor_irq)
  */
  
  
  /* FIXME: determine which include files are really needed */
  #include <linux/types.h>
  #include <linux/kernel.h>
  #include <linux/spinlock.h>
  #include <linux/pci.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/interrupt.h>
  
  #include <asm/byteorder.h>	/* get in-line asm for swab */
  #include <asm/pdc.h>
  #include <asm/pdcpat.h>
  #include <asm/page.h>

  #include <asm/io.h>		/* read/write functions */
  #ifdef CONFIG_SUPERIO
  #include <asm/superio.h>
  #endif

  #include <asm/ropes.h>

  #include "iosapic_private.h"

  
  #define MODULE_NAME "iosapic"
  
  /* "local" compile flags */
  #undef PCI_BRIDGE_FUNCS
  #undef DEBUG_IOSAPIC
  #undef DEBUG_IOSAPIC_IRT
  
  
  #ifdef DEBUG_IOSAPIC
  #define DBG(x...) printk(x)
  #else /* DEBUG_IOSAPIC */
  #define DBG(x...)
  #endif /* DEBUG_IOSAPIC */
  
  #ifdef DEBUG_IOSAPIC_IRT
  #define DBG_IRT(x...) printk(x)
  #else
  #define DBG_IRT(x...)
  #endif
  
  #ifdef CONFIG_64BIT
  #define COMPARE_IRTE_ADDR(irte, hpa)	((irte)->dest_iosapic_addr == (hpa))
  #else
  #define COMPARE_IRTE_ADDR(irte, hpa)	\
  		((irte)->dest_iosapic_addr == ((hpa) | 0xffffffff00000000ULL))
  #endif
  
  #define IOSAPIC_REG_SELECT              0x00
  #define IOSAPIC_REG_WINDOW              0x10
  #define IOSAPIC_REG_EOI                 0x40
  
  #define IOSAPIC_REG_VERSION		0x1
  
  #define IOSAPIC_IRDT_ENTRY(idx)		(0x10+(idx)*2)
  #define IOSAPIC_IRDT_ENTRY_HI(idx)	(0x11+(idx)*2)
  
  static inline unsigned int iosapic_read(void __iomem *iosapic, unsigned int reg)
  {
  	writel(reg, iosapic + IOSAPIC_REG_SELECT);
  	return readl(iosapic + IOSAPIC_REG_WINDOW);
  }
  
  static inline void iosapic_write(void __iomem *iosapic, unsigned int reg, u32 val)
  {
  	writel(reg, iosapic + IOSAPIC_REG_SELECT);
  	writel(val, iosapic + IOSAPIC_REG_WINDOW);
  }
  
  #define IOSAPIC_VERSION_MASK	0x000000ff
  #define	IOSAPIC_VERSION(ver)	((int) (ver & IOSAPIC_VERSION_MASK))
  
  #define IOSAPIC_MAX_ENTRY_MASK          0x00ff0000
  #define IOSAPIC_MAX_ENTRY_SHIFT         0x10
  #define	IOSAPIC_IRDT_MAX_ENTRY(ver)	\
  	(int) (((ver) & IOSAPIC_MAX_ENTRY_MASK) >> IOSAPIC_MAX_ENTRY_SHIFT)
  
  /* bits in the "low" I/O Sapic IRdT entry */
  #define IOSAPIC_IRDT_ENABLE       0x10000
  #define IOSAPIC_IRDT_PO_LOW       0x02000
  #define IOSAPIC_IRDT_LEVEL_TRIG   0x08000
  #define IOSAPIC_IRDT_MODE_LPRI    0x00100
  
  /* bits in the "high" I/O Sapic IRdT entry */
  #define IOSAPIC_IRDT_ID_EID_SHIFT              0x10

  static DEFINE_SPINLOCK(iosapic_lock);

  
  static inline void iosapic_eoi(void __iomem *addr, unsigned int data)
  {
  	__raw_writel(data, addr);
  }
  
  /*
  ** REVISIT: future platforms may have more than one IRT.
  ** If so, the following three fields form a structure which
  ** then be linked into a list. Names are chosen to make searching
  ** for them easy - not necessarily accurate (eg "cell").
  **
  ** Alternative: iosapic_info could point to the IRT it's in.
  ** iosapic_register() could search a list of IRT's.
  */
  static struct irt_entry *irt_cell;
  static size_t irt_num_entry;
  
  static struct irt_entry *iosapic_alloc_irt(int num_entries)
  {
  	unsigned long a;
  
  	/* The IRT needs to be 8-byte aligned for the PDC call. 
  	 * Normally kmalloc would guarantee larger alignment, but
  	 * if CONFIG_DEBUG_SLAB is enabled, then we can get only
  	 * 4-byte alignment on 32-bit kernels
  	 */
  	a = (unsigned long)kmalloc(sizeof(struct irt_entry) * num_entries + 8, GFP_KERNEL);

  	a = (a + 7UL) & ~7UL;

  	return (struct irt_entry *)a;
  }
  
  /**
   * iosapic_load_irt - Fill in the interrupt routing table
   * @cell_num: The cell number of the CPU we're currently executing on
   * @irt: The address to place the new IRT at
   * @return The number of entries found
   *
   * The "Get PCI INT Routing Table Size" option returns the number of 
   * entries in the PCI interrupt routing table for the cell specified 
   * in the cell_number argument.  The cell number must be for a cell 
   * within the caller's protection domain.
   *
   * The "Get PCI INT Routing Table" option returns, for the cell 
   * specified in the cell_number argument, the PCI interrupt routing 
   * table in the caller allocated memory pointed to by mem_addr.
   * We assume the IRT only contains entries for I/O SAPIC and
   * calculate the size based on the size of I/O sapic entries.
   *
   * The PCI interrupt routing table entry format is derived from the
   * IA64 SAL Specification 2.4.   The PCI interrupt routing table defines
   * the routing of PCI interrupt signals between the PCI device output
   * "pins" and the IO SAPICs' input "lines" (including core I/O PCI
   * devices).  This table does NOT include information for devices/slots
   * behind PCI to PCI bridges. See PCI to PCI Bridge Architecture Spec.
   * for the architected method of routing of IRQ's behind PPB's.
   */
  
  
  static int __init
  iosapic_load_irt(unsigned long cell_num, struct irt_entry **irt)
  {
  	long status;              /* PDC return value status */
  	struct irt_entry *table;  /* start of interrupt routing tbl */
  	unsigned long num_entries = 0UL;
  
  	BUG_ON(!irt);
  
  	if (is_pdc_pat()) {
  		/* Use pat pdc routine to get interrupt routing table size */
  		DBG("calling get_irt_size (cell %ld)
  ", cell_num);
  		status = pdc_pat_get_irt_size(&num_entries, cell_num);
  		DBG("get_irt_size: %ld
  ", status);
  
  		BUG_ON(status != PDC_OK);
  		BUG_ON(num_entries == 0);
  
  		/*
  		** allocate memory for interrupt routing table
  		** This interface isn't really right. We are assuming
  		** the contents of the table are exclusively
  		** for I/O sapic devices.
  		*/
  		table = iosapic_alloc_irt(num_entries);
  		if (table == NULL) {
  			printk(KERN_WARNING MODULE_NAME ": read_irt : can "
  					"not alloc mem for IRT
  ");
  			return 0;
  		}
  
  		/* get PCI INT routing table */
  		status = pdc_pat_get_irt(table, cell_num);
  		DBG("pdc_pat_get_irt: %ld
  ", status);
  		WARN_ON(status != PDC_OK);
  	} else {
  		/*
  		** C3000/J5000 (and similar) platforms with Sprockets PDC
  		** will return exactly one IRT for all iosapics.
  		** So if we have one, don't need to get it again.
  		*/
  		if (irt_cell)
  			return 0;
  
  		/* Should be using the Elroy's HPA, but it's ignored anyway */
  		status = pdc_pci_irt_size(&num_entries, 0);
  		DBG("pdc_pci_irt_size: %ld
  ", status);
  
  		if (status != PDC_OK) {
  			/* Not a "legacy" system with I/O SAPIC either */
  			return 0;
  		}
  
  		BUG_ON(num_entries == 0);
  
  		table = iosapic_alloc_irt(num_entries);
  		if (!table) {
  			printk(KERN_WARNING MODULE_NAME ": read_irt : can "
  					"not alloc mem for IRT
  ");
  			return 0;
  		}
  
  		/* HPA ignored by this call too. */
  		status = pdc_pci_irt(num_entries, 0, table);
  		BUG_ON(status != PDC_OK);
  	}
  
  	/* return interrupt table address */
  	*irt = table;
  
  #ifdef DEBUG_IOSAPIC_IRT
  {
  	struct irt_entry *p = table;
  	int i;
  
  	printk(MODULE_NAME " Interrupt Routing Table (cell %ld)
  ", cell_num);
  	printk(MODULE_NAME " start = 0x%p num_entries %ld entry_size %d
  ",
  		table,
  		num_entries,
  		(int) sizeof(struct irt_entry));
  
  	for (i = 0 ; i < num_entries ; i++, p++) {
  		printk(MODULE_NAME " %02x %02x %02x %02x %02x %02x %02x %02x %08x%08x
  ",
  		p->entry_type, p->entry_length, p->interrupt_type,
  		p->polarity_trigger, p->src_bus_irq_devno, p->src_bus_id,
  		p->src_seg_id, p->dest_iosapic_intin,
  		((u32 *) p)[2],
  		((u32 *) p)[3]
  		);
  	}
  }
  #endif /* DEBUG_IOSAPIC_IRT */
  
  	return num_entries;
  }
  
  
  
  void __init iosapic_init(void)
  {
  	unsigned long cell = 0;
  
  	DBG("iosapic_init()
  ");
  
  #ifdef __LP64__
  	if (is_pdc_pat()) {
  		int status;
  		struct pdc_pat_cell_num cell_info;
  
  		status = pdc_pat_cell_get_number(&cell_info);
  		if (status == PDC_OK) {
  			cell = cell_info.cell_num;
  		}
  	}
  #endif
  
  	/* get interrupt routing table for this cell */
  	irt_num_entry = iosapic_load_irt(cell, &irt_cell);
  	if (irt_num_entry == 0)
  		irt_cell = NULL;	/* old PDC w/o iosapic */
  }
  
  
  /*
  ** Return the IRT entry in case we need to look something else up.
  */
  static struct irt_entry *
  irt_find_irqline(struct iosapic_info *isi, u8 slot, u8 intr_pin)
  {
  	struct irt_entry *i = irt_cell;
  	int cnt;	/* track how many entries we've looked at */
  	u8 irq_devno = (slot << IRT_DEV_SHIFT) | (intr_pin-1);
  
  	DBG_IRT("irt_find_irqline() SLOT %d pin %d
  ", slot, intr_pin);
  
  	for (cnt=0; cnt < irt_num_entry; cnt++, i++) {
  
  		/*
  		** Validate: entry_type, entry_length, interrupt_type
  		**
  		** Difference between validate vs compare is the former
  		** should print debug info and is not expected to "fail"
  		** on current platforms.
  		*/
  		if (i->entry_type != IRT_IOSAPIC_TYPE) {
  			DBG_IRT(KERN_WARNING MODULE_NAME ":find_irqline(0x%p): skipping entry %d type %d
  ", i, cnt, i->entry_type);
  			continue;
  		}
  		
  		if (i->entry_length != IRT_IOSAPIC_LENGTH) {
  			DBG_IRT(KERN_WARNING MODULE_NAME ":find_irqline(0x%p): skipping entry %d  length %d
  ", i, cnt, i->entry_length);
  			continue;
  		}
  
  		if (i->interrupt_type != IRT_VECTORED_INTR) {
  			DBG_IRT(KERN_WARNING MODULE_NAME ":find_irqline(0x%p): skipping entry  %d interrupt_type %d
  ", i, cnt, i->interrupt_type);
  			continue;
  		}
  
  		if (!COMPARE_IRTE_ADDR(i, isi->isi_hpa))
  			continue;
  
  		if ((i->src_bus_irq_devno & IRT_IRQ_DEVNO_MASK) != irq_devno)
  			continue;
  
  		/*
  		** Ignore: src_bus_id and rc_seg_id correlate with
  		**         iosapic_info->isi_hpa on HP platforms.
  		**         If needed, pass in "PFA" (aka config space addr)
  		**         instead of slot.
  		*/
  
  		/* Found it! */
  		return i;
  	}
  
  	printk(KERN_WARNING MODULE_NAME ": 0x%lx : no IRT entry for slot %d, pin %d
  ",
  			isi->isi_hpa, slot, intr_pin);
  	return NULL;
  }
  
  
  /*
  ** xlate_pin() supports the skewing of IRQ lines done by subsidiary bridges.
  ** Legacy PDC already does this translation for us and stores it in INTR_LINE.
  **
  ** PAT PDC needs to basically do what legacy PDC does:
  ** o read PIN
  ** o adjust PIN in case device is "behind" a PPB
  **     (eg 4-port 100BT and SCSI/LAN "Combo Card")
  ** o convert slot/pin to I/O SAPIC input line.
  **
  ** HP platforms only support:
  ** o one level of skewing for any number of PPBs
  ** o only support PCI-PCI Bridges.
  */
  static struct irt_entry *
  iosapic_xlate_pin(struct iosapic_info *isi, struct pci_dev *pcidev)
  {
  	u8 intr_pin, intr_slot;
  
  	pci_read_config_byte(pcidev, PCI_INTERRUPT_PIN, &intr_pin);
  
  	DBG_IRT("iosapic_xlate_pin(%s) SLOT %d pin %d
  ",
  		pcidev->slot_name, PCI_SLOT(pcidev->devfn), intr_pin);
  
  	if (intr_pin == 0) {
  		/* The device does NOT support/use IRQ lines.  */
  		return NULL;
  	}
  
  	/* Check if pcidev behind a PPB */

  	if (pcidev->bus->parent) {

  		/* Convert pcidev INTR_PIN into something we
  		** can lookup in the IRT.
  		*/
  #ifdef PCI_BRIDGE_FUNCS
  		/*
  		** Proposal #1:
  		**
  		** call implementation specific translation function
  		** This is architecturally "cleaner". HP-UX doesn't
  		** support other secondary bus types (eg. E/ISA) directly.
  		** May be needed for other processor (eg IA64) architectures
  		** or by some ambitous soul who wants to watch TV.
  		*/
  		if (pci_bridge_funcs->xlate_intr_line) {
  			intr_pin = pci_bridge_funcs->xlate_intr_line(pcidev);
  		}
  #else	/* PCI_BRIDGE_FUNCS */
  		struct pci_bus *p = pcidev->bus;
  		/*
  		** Proposal #2:
  		** The "pin" is skewed ((pin + dev - 1) % 4).
  		**
  		** This isn't very clean since I/O SAPIC must assume:
  		**   - all platforms only have PCI busses.
  		**   - only PCI-PCI bridge (eg not PCI-EISA, PCI-PCMCIA)
  		**   - IRQ routing is only skewed once regardless of
  		**     the number of PPB's between iosapic and device.
  		**     (Bit3 expansion chassis follows this rule)
  		**
  		** Advantage is it's really easy to implement.
  		*/

  		intr_pin = pci_swizzle_interrupt_pin(pcidev, intr_pin);

  #endif /* PCI_BRIDGE_FUNCS */
  
  		/*

  		 * Locate the host slot of the PPB.
  		 */
  		while (p->parent->parent)

  			p = p->parent;
  
  		intr_slot = PCI_SLOT(p->self->devfn);
  	} else {
  		intr_slot = PCI_SLOT(pcidev->devfn);
  	}
  	DBG_IRT("iosapic_xlate_pin:  bus %d slot %d pin %d
  ",

  			pcidev->bus->busn_res.start, intr_slot, intr_pin);

  
  	return irt_find_irqline(isi, intr_slot, intr_pin);
  }
  
  static void iosapic_rd_irt_entry(struct vector_info *vi , u32 *dp0, u32 *dp1)
  {
  	struct iosapic_info *isp = vi->iosapic;
  	u8 idx = vi->irqline;
  
  	*dp0 = iosapic_read(isp->addr, IOSAPIC_IRDT_ENTRY(idx));
  	*dp1 = iosapic_read(isp->addr, IOSAPIC_IRDT_ENTRY_HI(idx));
  }
  
  
  static void iosapic_wr_irt_entry(struct vector_info *vi, u32 dp0, u32 dp1)
  {
  	struct iosapic_info *isp = vi->iosapic;
  
  	DBG_IRT("iosapic_wr_irt_entry(): irq %d hpa %lx 0x%x 0x%x
  ",
  		vi->irqline, isp->isi_hpa, dp0, dp1);
  
  	iosapic_write(isp->addr, IOSAPIC_IRDT_ENTRY(vi->irqline), dp0);
  
  	/* Read the window register to flush the writes down to HW  */
  	dp0 = readl(isp->addr+IOSAPIC_REG_WINDOW);
  
  	iosapic_write(isp->addr, IOSAPIC_IRDT_ENTRY_HI(vi->irqline), dp1);
  
  	/* Read the window register to flush the writes down to HW  */
  	dp1 = readl(isp->addr+IOSAPIC_REG_WINDOW);
  }
  
  /*
  ** set_irt prepares the data (dp0, dp1) according to the vector_info
  ** and target cpu (id_eid).  dp0/dp1 are then used to program I/O SAPIC
  ** IRdT for the given "vector" (aka IRQ line).
  */
  static void
  iosapic_set_irt_data( struct vector_info *vi, u32 *dp0, u32 *dp1)
  {
  	u32 mode = 0;
  	struct irt_entry *p = vi->irte;
  
  	if ((p->polarity_trigger & IRT_PO_MASK) == IRT_ACTIVE_LO)
  		mode |= IOSAPIC_IRDT_PO_LOW;
  
  	if (((p->polarity_trigger >> IRT_EL_SHIFT) & IRT_EL_MASK) == IRT_LEVEL_TRIG)
  		mode |= IOSAPIC_IRDT_LEVEL_TRIG;
  
  	/*
  	** IA64 REVISIT
  	** PA doesn't support EXTINT or LPRIO bits.
  	*/
  
  	*dp0 = mode | (u32) vi->txn_data;
  
  	/*
  	** Extracting id_eid isn't a real clean way of getting it.
  	** But the encoding is the same for both PA and IA64 platforms.
  	*/
  	if (is_pdc_pat()) {
  		/*
  		** PAT PDC just hands it to us "right".
  		** txn_addr comes from cpu_data[x].txn_addr.
  		*/
  		*dp1 = (u32) (vi->txn_addr);
  	} else {
  		/* 
  		** eg if base_addr == 0xfffa0000),
  		**    we want to get 0xa0ff0000.
  		**
  		** eid	0x0ff00000 -> 0x00ff0000
  		** id	0x000ff000 -> 0xff000000
  		*/
  		*dp1 = (((u32)vi->txn_addr & 0x0ff00000) >> 4) |
  			(((u32)vi->txn_addr & 0x000ff000) << 12);
  	}
  	DBG_IRT("iosapic_set_irt_data(): 0x%x 0x%x
  ", *dp0, *dp1);
  }

  static void iosapic_mask_irq(struct irq_data *d)

  {
  	unsigned long flags;

  	struct vector_info *vi = irq_data_get_irq_chip_data(d);

  	u32 d0, d1;
  
  	spin_lock_irqsave(&iosapic_lock, flags);
  	iosapic_rd_irt_entry(vi, &d0, &d1);
  	d0 |= IOSAPIC_IRDT_ENABLE;
  	iosapic_wr_irt_entry(vi, d0, d1);
  	spin_unlock_irqrestore(&iosapic_lock, flags);
  }

  static void iosapic_unmask_irq(struct irq_data *d)

  {

  	struct vector_info *vi = irq_data_get_irq_chip_data(d);

  	u32 d0, d1;
  
  	/* data is initialized by fixup_irq */
  	WARN_ON(vi->txn_irq  == 0);
  
  	iosapic_set_irt_data(vi, &d0, &d1);
  	iosapic_wr_irt_entry(vi, d0, d1);
  
  #ifdef DEBUG_IOSAPIC_IRT
  {
  	u32 *t = (u32 *) ((ulong) vi->eoi_addr & ~0xffUL);
  	printk("iosapic_enable_irq(): regs %p", vi->eoi_addr);
  	for ( ; t < vi->eoi_addr; t++)
  		printk(" %x", readl(t));
  	printk("
  ");
  }
  
  printk("iosapic_enable_irq(): sel ");
  {
  	struct iosapic_info *isp = vi->iosapic;
  
  	for (d0=0x10; d0<0x1e; d0++) {
  		d1 = iosapic_read(isp->addr, d0);
  		printk(" %x", d1);
  	}
  }
  printk("
  ");
  #endif
  
  	/*
  	 * Issuing I/O SAPIC an EOI causes an interrupt IFF IRQ line is
  	 * asserted.  IRQ generally should not be asserted when a driver
  	 * enables their IRQ. It can lead to "interesting" race conditions
  	 * in the driver initialization sequence.
  	 */

  	DBG(KERN_DEBUG "enable_irq(%d): eoi(%p, 0x%x)
  ", d->irq,

  			vi->eoi_addr, vi->eoi_data);
  	iosapic_eoi(vi->eoi_addr, vi->eoi_data);

  }

  static void iosapic_eoi_irq(struct irq_data *d)

  {

  	struct vector_info *vi = irq_data_get_irq_chip_data(d);

  
  	iosapic_eoi(vi->eoi_addr, vi->eoi_data);

  	cpu_eoi_irq(d);

  }

  #ifdef CONFIG_SMP

  static int iosapic_set_affinity_irq(struct irq_data *d,
  				    const struct cpumask *dest, bool force)

  {

  	struct vector_info *vi = irq_data_get_irq_chip_data(d);

  	u32 d0, d1, dummy_d0;
  	unsigned long flags;

  	int dest_cpu;

  	dest_cpu = cpu_check_affinity(d, dest);

  	if (dest_cpu < 0)

  		return -1;

  	cpumask_copy(d->affinity, cpumask_of(dest_cpu));
  	vi->txn_addr = txn_affinity_addr(d->irq, dest_cpu);

  
  	spin_lock_irqsave(&iosapic_lock, flags);
  	/* d1 contains the destination CPU, so only want to set that
  	 * entry */
  	iosapic_rd_irt_entry(vi, &d0, &d1);
  	iosapic_set_irt_data(vi, &dummy_d0, &d1);
  	iosapic_wr_irt_entry(vi, d0, d1);
  	spin_unlock_irqrestore(&iosapic_lock, flags);

  
  	return 0;

  }
  #endif

  static struct irq_chip iosapic_interrupt_type = {

  	.name		=	"IO-SAPIC-level",
  	.irq_unmask	=	iosapic_unmask_irq,
  	.irq_mask	=	iosapic_mask_irq,
  	.irq_ack	=	cpu_ack_irq,
  	.irq_eoi	=	iosapic_eoi_irq,

  #ifdef CONFIG_SMP

  	.irq_set_affinity =	iosapic_set_affinity_irq,

  #endif

  };
  
  int iosapic_fixup_irq(void *isi_obj, struct pci_dev *pcidev)
  {
  	struct iosapic_info *isi = isi_obj;
  	struct irt_entry *irte = NULL;  /* only used if PAT PDC */
  	struct vector_info *vi;
  	int isi_line;	/* line used by device */
  
  	if (!isi) {
  		printk(KERN_WARNING MODULE_NAME ": hpa not registered for %s
  ",
  			pci_name(pcidev));
  		return -1;
  	}
  
  #ifdef CONFIG_SUPERIO
  	/*
  	 * HACK ALERT! (non-compliant PCI device support)
  	 *
  	 * All SuckyIO interrupts are routed through the PIC's on function 1.
  	 * But SuckyIO OHCI USB controller gets an IRT entry anyway because
  	 * it advertises INT D for INT_PIN.  Use that IRT entry to get the
  	 * SuckyIO interrupt routing for PICs on function 1 (*BLEECCHH*).
  	 */
  	if (is_superio_device(pcidev)) {
  		/* We must call superio_fixup_irq() to register the pdev */
  		pcidev->irq = superio_fixup_irq(pcidev);
  
  		/* Don't return if need to program the IOSAPIC's IRT... */
  		if (PCI_FUNC(pcidev->devfn) != SUPERIO_USB_FN)
  			return pcidev->irq;
  	}
  #endif /* CONFIG_SUPERIO */
  
  	/* lookup IRT entry for isi/slot/pin set */
  	irte = iosapic_xlate_pin(isi, pcidev);
  	if (!irte) {
  		printk("iosapic: no IRTE for %s (IRQ not connected?)
  ",
  				pci_name(pcidev));
  		return -1;
  	}
  	DBG_IRT("iosapic_fixup_irq(): irte %p %x %x %x %x %x %x %x %x
  ",
  		irte,
  		irte->entry_type,
  		irte->entry_length,
  		irte->polarity_trigger,
  		irte->src_bus_irq_devno,
  		irte->src_bus_id,
  		irte->src_seg_id,
  		irte->dest_iosapic_intin,
  		(u32) irte->dest_iosapic_addr);
  	isi_line = irte->dest_iosapic_intin;
  
  	/* get vector info for this input line */
  	vi = isi->isi_vector + isi_line;
  	DBG_IRT("iosapic_fixup_irq:  line %d vi 0x%p
  ", isi_line, vi);
  
  	/* If this IRQ line has already been setup, skip it */
  	if (vi->irte)
  		goto out;
  
  	vi->irte = irte;
  
  	/*
  	 * Allocate processor IRQ
  	 *
  	 * XXX/FIXME The txn_alloc_irq() code and related code should be
  	 * moved to enable_irq(). That way we only allocate processor IRQ
  	 * bits for devices that actually have drivers claiming them.
  	 * Right now we assign an IRQ to every PCI device present,
  	 * regardless of whether it's used or not.
  	 */
  	vi->txn_irq = txn_alloc_irq(8);
  
  	if (vi->txn_irq < 0)
  		panic("I/O sapic: couldn't get TXN IRQ
  ");
  
  	/* enable_irq() will use txn_* to program IRdT */
  	vi->txn_addr = txn_alloc_addr(vi->txn_irq);
  	vi->txn_data = txn_alloc_data(vi->txn_irq);
  
  	vi->eoi_addr = isi->addr + IOSAPIC_REG_EOI;
  	vi->eoi_data = cpu_to_le32(vi->txn_data);
  
  	cpu_claim_irq(vi->txn_irq, &iosapic_interrupt_type, vi);
  
   out:
  	pcidev->irq = vi->txn_irq;
  
  	DBG_IRT("iosapic_fixup_irq() %d:%d %x %x line %d irq %d
  ",
  		PCI_SLOT(pcidev->devfn), PCI_FUNC(pcidev->devfn),
  		pcidev->vendor, pcidev->device, isi_line, pcidev->irq);
  
  	return pcidev->irq;
  }

  static struct iosapic_info *iosapic_list;

  
  #ifdef CONFIG_64BIT

  int iosapic_serial_irq(struct parisc_device *dev)

  {

  	struct iosapic_info *isi;
  	struct irt_entry *irte;

  	struct vector_info *vi;

  	int cnt;
  	int intin;
  
  	intin = (dev->mod_info >> 24) & 15;

  
  	/* lookup IRT entry for isi/slot/pin set */

  	for (cnt = 0; cnt < irt_num_entry; cnt++) {
  		irte = &irt_cell[cnt];
  		if (COMPARE_IRTE_ADDR(irte, dev->mod0) &&
  		    irte->dest_iosapic_intin == intin)
  			break;
  	}
  	if (cnt >= irt_num_entry)
  		return 0; /* no irq found, force polling */

  
  	DBG_IRT("iosapic_serial_irq(): irte %p %x %x %x %x %x %x %x %x
  ",
  		irte,
  		irte->entry_type,
  		irte->entry_length,
  		irte->polarity_trigger,
  		irte->src_bus_irq_devno,
  		irte->src_bus_id,
  		irte->src_seg_id,
  		irte->dest_iosapic_intin,
  		(u32) irte->dest_iosapic_addr);

  
  	/* search for iosapic */
  	for (isi = iosapic_list; isi; isi = isi->isi_next)
  		if (isi->isi_hpa == dev->mod0)
  			break;
  	if (!isi)
  		return 0; /* no iosapic found, force polling */

  
  	/* get vector info for this input line */

  	vi = isi->isi_vector + intin;
  	DBG_IRT("iosapic_serial_irq:  line %d vi 0x%p
  ", iosapic_intin, vi);

  
  	/* If this IRQ line has already been setup, skip it */
  	if (vi->irte)
  		goto out;
  
  	vi->irte = irte;
  
  	/*
  	 * Allocate processor IRQ
  	 *
  	 * XXX/FIXME The txn_alloc_irq() code and related code should be
  	 * moved to enable_irq(). That way we only allocate processor IRQ
  	 * bits for devices that actually have drivers claiming them.
  	 * Right now we assign an IRQ to every PCI device present,
  	 * regardless of whether it's used or not.
  	 */
  	vi->txn_irq = txn_alloc_irq(8);
  
  	if (vi->txn_irq < 0)
  		panic("I/O sapic: couldn't get TXN IRQ
  ");
  
  	/* enable_irq() will use txn_* to program IRdT */
  	vi->txn_addr = txn_alloc_addr(vi->txn_irq);
  	vi->txn_data = txn_alloc_data(vi->txn_irq);
  
  	vi->eoi_addr = isi->addr + IOSAPIC_REG_EOI;
  	vi->eoi_data = cpu_to_le32(vi->txn_data);
  
  	cpu_claim_irq(vi->txn_irq, &iosapic_interrupt_type, vi);
  
   out:
  
  	return vi->txn_irq;
  }
  #endif

  
  /*
  ** squirrel away the I/O Sapic Version
  */
  static unsigned int
  iosapic_rd_version(struct iosapic_info *isi)
  {
  	return iosapic_read(isi->addr, IOSAPIC_REG_VERSION);
  }
  
  
  /*
  ** iosapic_register() is called by "drivers" with an integrated I/O SAPIC.
  ** Caller must be certain they have an I/O SAPIC and know its MMIO address.
  **
  **	o allocate iosapic_info and add it to the list
  **	o read iosapic version and squirrel that away
  **	o read size of IRdT.
  **	o allocate and initialize isi_vector[]
  **	o allocate irq region
  */
  void *iosapic_register(unsigned long hpa)
  {
  	struct iosapic_info *isi = NULL;
  	struct irt_entry *irte = irt_cell;
  	struct vector_info *vip;
  	int cnt;	/* track how many entries we've looked at */
  
  	/*
  	 * Astro based platforms can only support PCI OLARD if they implement
  	 * PAT PDC.  Legacy PDC omits LBAs with no PCI devices from the IRT.
  	 * Search the IRT and ignore iosapic's which aren't in the IRT.
  	 */
  	for (cnt=0; cnt < irt_num_entry; cnt++, irte++) {
  		WARN_ON(IRT_IOSAPIC_TYPE != irte->entry_type);
  		if (COMPARE_IRTE_ADDR(irte, hpa))
  			break;
  	}
  
  	if (cnt >= irt_num_entry) {
  		DBG("iosapic_register() ignoring 0x%lx (NOT FOUND)
  ", hpa);
  		return NULL;
  	}

  	isi = kzalloc(sizeof(struct iosapic_info), GFP_KERNEL);

  	if (!isi) {
  		BUG();
  		return NULL;
  	}

  	isi->addr = ioremap_nocache(hpa, 4096);

  	isi->isi_hpa = hpa;
  	isi->isi_version = iosapic_rd_version(isi);
  	isi->isi_num_vectors = IOSAPIC_IRDT_MAX_ENTRY(isi->isi_version) + 1;

  	vip = isi->isi_vector = kcalloc(isi->isi_num_vectors,
  					sizeof(struct vector_info), GFP_KERNEL);

  	if (vip == NULL) {
  		kfree(isi);
  		return NULL;
  	}

  	for (cnt=0; cnt < isi->isi_num_vectors; cnt++, vip++) {
  		vip->irqline = (unsigned char) cnt;
  		vip->iosapic = isi;
  	}

  	isi->isi_next = iosapic_list;
  	iosapic_list = isi;

  	return isi;
  }
  
  
  #ifdef DEBUG_IOSAPIC
  
  static void
  iosapic_prt_irt(void *irt, long num_entry)
  {
  	unsigned int i, *irp = (unsigned int *) irt;
  
  
  	printk(KERN_DEBUG MODULE_NAME ": Interrupt Routing Table (%lx entries)
  ", num_entry);
  
  	for (i=0; i<num_entry; i++, irp += 4) {
  		printk(KERN_DEBUG "%p : %2d %.8x %.8x %.8x %.8x
  ",
  					irp, i, irp[0], irp[1], irp[2], irp[3]);
  	}
  }
  
  
  static void
  iosapic_prt_vi(struct vector_info *vi)
  {
  	printk(KERN_DEBUG MODULE_NAME ": vector_info[%d] is at %p
  ", vi->irqline, vi);
  	printk(KERN_DEBUG "\t\tstatus:	 %.4x
  ", vi->status);
  	printk(KERN_DEBUG "\t\ttxn_irq:  %d
  ",  vi->txn_irq);
  	printk(KERN_DEBUG "\t\ttxn_addr: %lx
  ", vi->txn_addr);
  	printk(KERN_DEBUG "\t\ttxn_data: %lx
  ", vi->txn_data);
  	printk(KERN_DEBUG "\t\teoi_addr: %p
  ",  vi->eoi_addr);
  	printk(KERN_DEBUG "\t\teoi_data: %x
  ",  vi->eoi_data);
  }
  
  
  static void
  iosapic_prt_isi(struct iosapic_info *isi)
  {
  	printk(KERN_DEBUG MODULE_NAME ": io_sapic_info at %p
  ", isi);
  	printk(KERN_DEBUG "\t\tisi_hpa:       %lx
  ", isi->isi_hpa);
  	printk(KERN_DEBUG "\t\tisi_status:    %x
  ", isi->isi_status);
  	printk(KERN_DEBUG "\t\tisi_version:   %x
  ", isi->isi_version);
  	printk(KERN_DEBUG "\t\tisi_vector:    %p
  ", isi->isi_vector);
  }
  #endif /* DEBUG_IOSAPIC */