hw/pci-host/versatile.c - qemu - Git at Google

 /*
  * ARM Versatile/PB PCI host controller
  *
  * Copyright (c) 2006-2009 CodeSourcery.
  * Written by Paul Brook
  *
  * This code is licensed under the LGPL.
  */

 #include "qemu/osdep.h"
 #include "qemu/units.h"
 #include "hw/sysbus.h"
 #include "migration/vmstate.h"
 #include "hw/irq.h"
 #include "hw/pci/pci_device.h"
 #include "hw/pci/pci_bus.h"
 #include "hw/pci/pci_host.h"
 #include "hw/qdev-properties.h"
 #include "qemu/log.h"
 #include "qemu/module.h"
 #include "qom/object.h"

 /* Old and buggy versions of QEMU used the wrong mapping from
  * PCI IRQs to system interrupt lines. Unfortunately the Linux
  * kernel also had the corresponding bug in setting up interrupts
  * (so older kernels work on QEMU and not on real hardware).
  * We automatically detect these broken kernels and flip back
  * to the broken irq mapping by spotting guest writes to the
  * PCI_INTERRUPT_LINE register to see where the guest thinks
  * interrupts are going to be routed. So we start in state
  * ASSUME_OK on reset, and transition to either BROKEN or
  * FORCE_OK at the first write to an INTERRUPT_LINE register for
  * a slot where broken and correct interrupt mapping would differ.
  * Once in either BROKEN or FORCE_OK we never transition again;
  * this allows a newer kernel to use the INTERRUPT_LINE
  * registers arbitrarily once it has indicated that it isn't
  * broken in its init code somewhere.
  *
  * Unfortunately we have to cope with multiple different
  * variants on the broken kernel behaviour:
  *  phase I (before kernel commit 1bc39ac5d) kernels assume old
  *   QEMU behaviour, so they use IRQ 27 for all slots
  *  phase II (1bc39ac5d and later, but before e3e92a7be6) kernels
  *   swizzle IRQs between slots, but do it wrongly, so they
  *   work only for every fourth PCI card, and only if (like old
  *   QEMU) the PCI host device is at slot 0 rather than where
  *   the h/w actually puts it
  *  phase III (e3e92a7be6 and later) kernels still swizzle IRQs between
  *   slots wrongly, but add a fixed offset of 64 to everything
  *   they write to PCI_INTERRUPT_LINE.
  *
  * We live in hope of a mythical phase IV kernel which might
  * actually behave in ways that work on the hardware. Such a
  * kernel should probably start off by writing some value neither
  * 27 nor 91 to slot zero's PCI_INTERRUPT_LINE register to
  * disable the autodetection. After that it can do what it likes.
  *
  * Slot % 4 | hw | I  | II | III
  * -------------------------------
  *   0      | 29 | 27 | 27 | 91
  *   1      | 30 | 27 | 28 | 92
  *   2      | 27 | 27 | 29 | 93
  *   3      | 28 | 27 | 30 | 94
  *
  * Since our autodetection is not perfect we also provide a
  * property so the user can make us start in BROKEN or FORCE_OK
  * on reset if they know they have a bad or good kernel.
  */
 enum {
     PCI_VPB_IRQMAP_ASSUME_OK,
     PCI_VPB_IRQMAP_BROKEN,
     PCI_VPB_IRQMAP_FORCE_OK,
 };

 struct PCIVPBState {
     PCIHostState parent_obj;

     qemu_irq irq[4];
     MemoryRegion controlregs;
     MemoryRegion mem_config;
     MemoryRegion mem_config2;
     /* Containers representing the PCI address spaces */
     MemoryRegion pci_io_space;
     MemoryRegion pci_mem_space;
     /* Alias regions into PCI address spaces which we expose as sysbus regions.
      * The offsets into pci_mem_space are controlled by the imap registers.
      */
     MemoryRegion pci_io_window;
     MemoryRegion pci_mem_window[3];
     PCIBus pci_bus;
     PCIDevice pci_dev;

     /* Constant for life of device: */
     int realview;
     uint32_t mem_win_size[3];
     uint8_t irq_mapping_prop;

     /* Variable state: */
     uint32_t imap[3];
     uint32_t smap[3];
     uint32_t selfid;
     uint32_t flags;
     uint8_t irq_mapping;
 };
 typedef struct PCIVPBState PCIVPBState;

 static void pci_vpb_update_window(PCIVPBState *s, int i)
 {
     /* Adjust the offset of the alias region we use for
      * the memory window i to account for a change in the
      * value of the corresponding IMAP register.
      * Note that the semantics of the IMAP register differ
      * for realview and versatile variants of the controller.
      */
     hwaddr offset;
     if (s->realview) {
         /* Top bits of register (masked according to window size) provide
          * top bits of PCI address.
          */
         offset = s->imap[i] & ~(s->mem_win_size[i] - 1);
     } else {
         /* Bottom 4 bits of register provide top 4 bits of PCI address */
         offset = s->imap[i] << 28;
     }
     memory_region_set_alias_offset(&s->pci_mem_window[i], offset);
 }

 static void pci_vpb_update_all_windows(PCIVPBState *s)
 {
     /* Update all alias windows based on the current register state */
     int i;

     for (i = 0; i < 3; i++) {
         pci_vpb_update_window(s, i);
     }
 }

 static int pci_vpb_post_load(void *opaque, int version_id)
 {
     PCIVPBState *s = opaque;
     pci_vpb_update_all_windows(s);
     return 0;
 }

 static const VMStateDescription pci_vpb_vmstate = {
     .name = "versatile-pci",
     .version_id = 1,
     .minimum_version_id = 1,
     .post_load = pci_vpb_post_load,
     .fields = (VMStateField[]) {
         VMSTATE_UINT32_ARRAY(imap, PCIVPBState, 3),
         VMSTATE_UINT32_ARRAY(smap, PCIVPBState, 3),
         VMSTATE_UINT32(selfid, PCIVPBState),
         VMSTATE_UINT32(flags, PCIVPBState),
         VMSTATE_UINT8(irq_mapping, PCIVPBState),
         VMSTATE_END_OF_LIST()
     }
 };

 #define TYPE_VERSATILE_PCI "versatile_pci"
 DECLARE_INSTANCE_CHECKER(PCIVPBState, PCI_VPB,
                          TYPE_VERSATILE_PCI)

 #define TYPE_VERSATILE_PCI_HOST "versatile_pci_host"
 DECLARE_INSTANCE_CHECKER(PCIDevice, PCI_VPB_HOST,
                          TYPE_VERSATILE_PCI_HOST)

 typedef enum {
     PCI_IMAP0 = 0x0,
     PCI_IMAP1 = 0x4,
     PCI_IMAP2 = 0x8,
     PCI_SELFID = 0xc,
     PCI_FLAGS = 0x10,
     PCI_SMAP0 = 0x14,
     PCI_SMAP1 = 0x18,
     PCI_SMAP2 = 0x1c,
 } PCIVPBControlRegs;

 static void pci_vpb_reg_write(void *opaque, hwaddr addr,
                               uint64_t val, unsigned size)
 {
     PCIVPBState *s = opaque;

     switch (addr) {
     case PCI_IMAP0:
     case PCI_IMAP1:
     case PCI_IMAP2:
     {
         int win = (addr - PCI_IMAP0) >> 2;
         s->imap[win] = val;
         pci_vpb_update_window(s, win);
         break;
     }
     case PCI_SELFID:
         s->selfid = val;
         break;
     case PCI_FLAGS:
         s->flags = val;
         break;
     case PCI_SMAP0:
     case PCI_SMAP1:
     case PCI_SMAP2:
     {
         int win = (addr - PCI_SMAP0) >> 2;
         s->smap[win] = val;
         break;
     }
     default:
         qemu_log_mask(LOG_GUEST_ERROR,
                       "pci_vpb_reg_write: Bad offset %x\n", (int)addr);
         break;
     }
 }

 static uint64_t pci_vpb_reg_read(void *opaque, hwaddr addr,
                                  unsigned size)
 {
     PCIVPBState *s = opaque;

     switch (addr) {
     case PCI_IMAP0:
     case PCI_IMAP1:
     case PCI_IMAP2:
     {
         int win = (addr - PCI_IMAP0) >> 2;
         return s->imap[win];
     }
     case PCI_SELFID:
         return s->selfid;
     case PCI_FLAGS:
         return s->flags;
     case PCI_SMAP0:
     case PCI_SMAP1:
     case PCI_SMAP2:
     {
         int win = (addr - PCI_SMAP0) >> 2;
         return s->smap[win];
     }
     default:
         qemu_log_mask(LOG_GUEST_ERROR,
                       "pci_vpb_reg_read: Bad offset %x\n", (int)addr);
         return 0;
     }
 }

 static const MemoryRegionOps pci_vpb_reg_ops = {
     .read = pci_vpb_reg_read,
     .write = pci_vpb_reg_write,
     .endianness = DEVICE_NATIVE_ENDIAN,
     .valid = {
         .min_access_size = 4,
         .max_access_size = 4,
     },
 };

 static int pci_vpb_broken_irq(int slot, int irq)
 {
     /* Determine whether this IRQ value for this slot represents a
      * known broken Linux kernel behaviour for this slot.
      * Return one of the PCI_VPB_IRQMAP_ constants:
      *   BROKEN : if this definitely looks like a broken kernel
      *   FORCE_OK : if this definitely looks good
      *   ASSUME_OK : if we can't tell
      */
     slot %= PCI_NUM_PINS;

     if (irq == 27) {
         if (slot == 2) {
             /* Might be a Phase I kernel, or might be a fixed kernel,
              * since slot 2 is where we expect this IRQ.
              */
             return PCI_VPB_IRQMAP_ASSUME_OK;
         }
         /* Phase I kernel */
         return PCI_VPB_IRQMAP_BROKEN;
     }
     if (irq == slot + 27) {
         /* Phase II kernel */
         return PCI_VPB_IRQMAP_BROKEN;
     }
     if (irq == slot + 27 + 64) {
         /* Phase III kernel */
         return PCI_VPB_IRQMAP_BROKEN;
     }
     /* Anything else must be a fixed kernel, possibly using an
      * arbitrary irq map.
      */
     return PCI_VPB_IRQMAP_FORCE_OK;
 }

 static void pci_vpb_config_write(void *opaque, hwaddr addr,
                                  uint64_t val, unsigned size)
 {
     PCIVPBState *s = opaque;
     if (!s->realview && (addr & 0xff) == PCI_INTERRUPT_LINE
         && s->irq_mapping == PCI_VPB_IRQMAP_ASSUME_OK) {
         uint8_t devfn = addr >> 8;
         s->irq_mapping = pci_vpb_broken_irq(PCI_SLOT(devfn), val);
     }
     pci_data_write(&s->pci_bus, addr, val, size);
 }

 static uint64_t pci_vpb_config_read(void *opaque, hwaddr addr,
                                     unsigned size)
 {
     PCIVPBState *s = opaque;
     uint32_t val;
     val = pci_data_read(&s->pci_bus, addr, size);
     return val;
 }

 static const MemoryRegionOps pci_vpb_config_ops = {
     .read = pci_vpb_config_read,
     .write = pci_vpb_config_write,
     .endianness = DEVICE_NATIVE_ENDIAN,
 };

 static int pci_vpb_map_irq(PCIDevice *d, int irq_num)
 {
     PCIVPBState *s = container_of(pci_get_bus(d), PCIVPBState, pci_bus);

     if (s->irq_mapping == PCI_VPB_IRQMAP_BROKEN) {
         /* Legacy broken IRQ mapping for compatibility with old and
          * buggy Linux guests
          */
         return irq_num;
     }

     /* Slot to IRQ mapping for RealView Platform Baseboard 926 backplane
      *      name    slot    IntA    IntB    IntC    IntD
      *      A       31      IRQ28   IRQ29   IRQ30   IRQ27
      *      B       30      IRQ27   IRQ28   IRQ29   IRQ30
      *      C       29      IRQ30   IRQ27   IRQ28   IRQ29
      * Slot C is for the host bridge; A and B the peripherals.
      * Our output irqs 0..3 correspond to the baseboard's 27..30.
      *
      * This mapping function takes account of an oddity in the PB926
      * board wiring, where the FPGA's P_nINTA input is connected to
      * the INTB connection on the board PCI edge connector, P_nINTB
      * is connected to INTC, and so on, so everything is one number
      * further round from where you might expect.
      */
     return pci_swizzle_map_irq_fn(d, irq_num + 2);
 }

 static int pci_vpb_rv_map_irq(PCIDevice *d, int irq_num)
 {
     /* Slot to IRQ mapping for RealView EB and PB1176 backplane
      *      name    slot    IntA    IntB    IntC    IntD
      *      A       31      IRQ50   IRQ51   IRQ48   IRQ49
      *      B       30      IRQ49   IRQ50   IRQ51   IRQ48
      *      C       29      IRQ48   IRQ49   IRQ50   IRQ51
      * Slot C is for the host bridge; A and B the peripherals.
      * Our output irqs 0..3 correspond to the baseboard's 48..51.
      *
      * The PB1176 and EB boards don't have the PB926 wiring oddity
      * described above; P_nINTA connects to INTA, P_nINTB to INTB
      * and so on, which is why this mapping function is different.
      */
     return pci_swizzle_map_irq_fn(d, irq_num + 3);
 }

 static void pci_vpb_set_irq(void *opaque, int irq_num, int level)
 {
     qemu_irq *pic = opaque;

     qemu_set_irq(pic[irq_num], level);
 }

 static void pci_vpb_reset(DeviceState *d)
 {
     PCIVPBState *s = PCI_VPB(d);

     s->imap[0] = 0;
     s->imap[1] = 0;
     s->imap[2] = 0;
     s->smap[0] = 0;
     s->smap[1] = 0;
     s->smap[2] = 0;
     s->selfid = 0;
     s->flags = 0;
     s->irq_mapping = s->irq_mapping_prop;

     pci_vpb_update_all_windows(s);
 }

 static void pci_vpb_init(Object *obj)
 {
     PCIVPBState *s = PCI_VPB(obj);

     /* Window sizes for VersatilePB; realview_pci's init will override */
     s->mem_win_size[0] = 0x0c000000;
     s->mem_win_size[1] = 0x10000000;
     s->mem_win_size[2] = 0x10000000;
 }

 static void pci_vpb_realize(DeviceState *dev, Error **errp)
 {
     PCIVPBState *s = PCI_VPB(dev);
     PCIHostState *h = PCI_HOST_BRIDGE(dev);
     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
     pci_map_irq_fn mapfn;
     int i;

     memory_region_init(&s->pci_io_space, OBJECT(s), "pci_io", 4 * GiB);
     memory_region_init(&s->pci_mem_space, OBJECT(s), "pci_mem", 4 * GiB);

     pci_root_bus_init(&s->pci_bus, sizeof(s->pci_bus), dev, "pci",
                       &s->pci_mem_space, &s->pci_io_space,
                       PCI_DEVFN(11, 0), TYPE_PCI_BUS);
     h->bus = &s->pci_bus;

     object_initialize(&s->pci_dev, sizeof(s->pci_dev), TYPE_VERSATILE_PCI_HOST);

     for (i = 0; i < 4; i++) {
         sysbus_init_irq(sbd, &s->irq[i]);
     }

     if (s->realview) {
         mapfn = pci_vpb_rv_map_irq;
     } else {
         mapfn = pci_vpb_map_irq;
     }

     pci_bus_irqs(&s->pci_bus, pci_vpb_set_irq, s->irq, 4);
     pci_bus_map_irqs(&s->pci_bus, mapfn);

     /* Our memory regions are:
      * 0 : our control registers
      * 1 : PCI self config window
      * 2 : PCI config window
      * 3 : PCI IO window
      * 4..6 : PCI memory windows
      */
     memory_region_init_io(&s->controlregs, OBJECT(s), &pci_vpb_reg_ops, s,
                           "pci-vpb-regs", 0x1000);
     sysbus_init_mmio(sbd, &s->controlregs);
     memory_region_init_io(&s->mem_config, OBJECT(s), &pci_vpb_config_ops, s,
                           "pci-vpb-selfconfig", 0x1000000);
     sysbus_init_mmio(sbd, &s->mem_config);
     memory_region_init_io(&s->mem_config2, OBJECT(s), &pci_vpb_config_ops, s,
                           "pci-vpb-config", 0x1000000);
     sysbus_init_mmio(sbd, &s->mem_config2);

     /* The window into I/O space is always into a fixed base address;
      * its size is the same for both realview and versatile.
      */
     memory_region_init_alias(&s->pci_io_window, OBJECT(s), "pci-vbp-io-window",
                              &s->pci_io_space, 0, 0x100000);

     sysbus_init_mmio(sbd, &s->pci_io_space);

     /* Create the alias regions corresponding to our three windows onto
      * PCI memory space. The sizes vary from board to board; the base
      * offsets are guest controllable via the IMAP registers.
      */
     for (i = 0; i < 3; i++) {
         memory_region_init_alias(&s->pci_mem_window[i], OBJECT(s), "pci-vbp-window",
                                  &s->pci_mem_space, 0, s->mem_win_size[i]);
         sysbus_init_mmio(sbd, &s->pci_mem_window[i]);
     }

     /* TODO Remove once realize propagates to child devices. */
     qdev_realize(DEVICE(&s->pci_dev), BUS(&s->pci_bus), errp);
 }

 static void versatile_pci_host_realize(PCIDevice *d, Error **errp)
 {
     pci_set_word(d->config + PCI_STATUS,
                  PCI_STATUS_66MHZ | PCI_STATUS_DEVSEL_MEDIUM);
     pci_set_byte(d->config + PCI_LATENCY_TIMER, 0x10);
 }

 static void versatile_pci_host_class_init(ObjectClass *klass, void *data)
 {
     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
     DeviceClass *dc = DEVICE_CLASS(klass);

     k->realize = versatile_pci_host_realize;
     k->vendor_id = PCI_VENDOR_ID_XILINX;
     k->device_id = PCI_DEVICE_ID_XILINX_XC2VP30;
     k->class_id = PCI_CLASS_PROCESSOR_CO;
     /*
      * PCI-facing part of the host bridge, not usable without the
      * host-facing part, which can't be device_add'ed, yet.
      */
     dc->user_creatable = false;
 }

 static const TypeInfo versatile_pci_host_info = {
     .name          = TYPE_VERSATILE_PCI_HOST,
     .parent        = TYPE_PCI_DEVICE,
     .instance_size = sizeof(PCIDevice),
     .class_init    = versatile_pci_host_class_init,
     .interfaces = (InterfaceInfo[]) {
         { INTERFACE_CONVENTIONAL_PCI_DEVICE },
         { },
     },
 };

 static Property pci_vpb_properties[] = {
     DEFINE_PROP_UINT8("broken-irq-mapping", PCIVPBState, irq_mapping_prop,
                       PCI_VPB_IRQMAP_ASSUME_OK),
     DEFINE_PROP_END_OF_LIST()
 };

 static void pci_vpb_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);

     dc->realize = pci_vpb_realize;
     dc->reset = pci_vpb_reset;
     dc->vmsd = &pci_vpb_vmstate;
     device_class_set_props(dc, pci_vpb_properties);
 }

 static const TypeInfo pci_vpb_info = {
     .name          = TYPE_VERSATILE_PCI,
     .parent        = TYPE_PCI_HOST_BRIDGE,
     .instance_size = sizeof(PCIVPBState),
     .instance_init = pci_vpb_init,
     .class_init    = pci_vpb_class_init,
 };

 static void pci_realview_init(Object *obj)
 {
     PCIVPBState *s = PCI_VPB(obj);

     s->realview = 1;
     /* The PCI window sizes are different on Realview boards */
     s->mem_win_size[0] = 0x01000000;
     s->mem_win_size[1] = 0x04000000;
     s->mem_win_size[2] = 0x08000000;
 }

 static const TypeInfo pci_realview_info = {
     .name          = "realview_pci",
     .parent        = TYPE_VERSATILE_PCI,
     .instance_init = pci_realview_init,
 };

 static void versatile_pci_register_types(void)
 {
     type_register_static(&pci_vpb_info);
     type_register_static(&pci_realview_info);
     type_register_static(&versatile_pci_host_info);
 }

 type_init(versatile_pci_register_types)
	/*
	* ARM Versatile/PB PCI host controller
	*
	* Copyright (c) 2006-2009 CodeSourcery.
	* Written by Paul Brook
	*
	* This code is licensed under the LGPL.
	*/

	#include "qemu/osdep.h"
	#include "qemu/units.h"
	#include "hw/sysbus.h"
	#include "migration/vmstate.h"
	#include "hw/irq.h"
	#include "hw/pci/pci_device.h"
	#include "hw/pci/pci_bus.h"
	#include "hw/pci/pci_host.h"
	#include "hw/qdev-properties.h"
	#include "qemu/log.h"
	#include "qemu/module.h"
	#include "qom/object.h"

	/* Old and buggy versions of QEMU used the wrong mapping from
	* PCI IRQs to system interrupt lines. Unfortunately the Linux
	* kernel also had the corresponding bug in setting up interrupts
	* (so older kernels work on QEMU and not on real hardware).
	* We automatically detect these broken kernels and flip back
	* to the broken irq mapping by spotting guest writes to the
	* PCI_INTERRUPT_LINE register to see where the guest thinks
	* interrupts are going to be routed. So we start in state
	* ASSUME_OK on reset, and transition to either BROKEN or
	* FORCE_OK at the first write to an INTERRUPT_LINE register for
	* a slot where broken and correct interrupt mapping would differ.
	* Once in either BROKEN or FORCE_OK we never transition again;
	* this allows a newer kernel to use the INTERRUPT_LINE
	* registers arbitrarily once it has indicated that it isn't
	* broken in its init code somewhere.
	*
	* Unfortunately we have to cope with multiple different
	* variants on the broken kernel behaviour:
	* phase I (before kernel commit 1bc39ac5d) kernels assume old
	* QEMU behaviour, so they use IRQ 27 for all slots
	* phase II (1bc39ac5d and later, but before e3e92a7be6) kernels
	* swizzle IRQs between slots, but do it wrongly, so they
	* work only for every fourth PCI card, and only if (like old
	* QEMU) the PCI host device is at slot 0 rather than where
	* the h/w actually puts it
	* phase III (e3e92a7be6 and later) kernels still swizzle IRQs between
	* slots wrongly, but add a fixed offset of 64 to everything
	* they write to PCI_INTERRUPT_LINE.
	*
	* We live in hope of a mythical phase IV kernel which might
	* actually behave in ways that work on the hardware. Such a
	* kernel should probably start off by writing some value neither
	* 27 nor 91 to slot zero's PCI_INTERRUPT_LINE register to
	* disable the autodetection. After that it can do what it likes.
	*
	* Slot % 4 \| hw \| I \| II \| III
	* -------------------------------
	* 0 \| 29 \| 27 \| 27 \| 91
	* 1 \| 30 \| 27 \| 28 \| 92
	* 2 \| 27 \| 27 \| 29 \| 93
	* 3 \| 28 \| 27 \| 30 \| 94
	*
	* Since our autodetection is not perfect we also provide a
	* property so the user can make us start in BROKEN or FORCE_OK
	* on reset if they know they have a bad or good kernel.
	*/
	enum {
	PCI_VPB_IRQMAP_ASSUME_OK,
	PCI_VPB_IRQMAP_BROKEN,
	PCI_VPB_IRQMAP_FORCE_OK,
	};

	struct PCIVPBState {
	PCIHostState parent_obj;

	qemu_irq irq[4];
	MemoryRegion controlregs;
	MemoryRegion mem_config;
	MemoryRegion mem_config2;
	/* Containers representing the PCI address spaces */
	MemoryRegion pci_io_space;
	MemoryRegion pci_mem_space;
	/* Alias regions into PCI address spaces which we expose as sysbus regions.
	* The offsets into pci_mem_space are controlled by the imap registers.
	*/
	MemoryRegion pci_io_window;
	MemoryRegion pci_mem_window[3];
	PCIBus pci_bus;
	PCIDevice pci_dev;

	/* Constant for life of device: */
	int realview;
	uint32_t mem_win_size[3];
	uint8_t irq_mapping_prop;

	/* Variable state: */
	uint32_t imap[3];
	uint32_t smap[3];
	uint32_t selfid;
	uint32_t flags;
	uint8_t irq_mapping;
	};
	typedef struct PCIVPBState PCIVPBState;

	static void pci_vpb_update_window(PCIVPBState *s, int i)
	{
	/* Adjust the offset of the alias region we use for
	* the memory window i to account for a change in the
	* value of the corresponding IMAP register.
	* Note that the semantics of the IMAP register differ
	* for realview and versatile variants of the controller.
	*/
	hwaddr offset;
	if (s->realview) {
	/* Top bits of register (masked according to window size) provide
	* top bits of PCI address.
	*/
	offset = s->imap[i] & ~(s->mem_win_size[i] - 1);
	} else {
	/* Bottom 4 bits of register provide top 4 bits of PCI address */
	offset = s->imap[i] << 28;
	}
	memory_region_set_alias_offset(&s->pci_mem_window[i], offset);
	}

	static void pci_vpb_update_all_windows(PCIVPBState *s)
	{
	/* Update all alias windows based on the current register state */
	int i;

	for (i = 0; i < 3; i++) {
	pci_vpb_update_window(s, i);
	}
	}

	static int pci_vpb_post_load(void *opaque, int version_id)
	{
	PCIVPBState *s = opaque;
	pci_vpb_update_all_windows(s);
	return 0;
	}

	static const VMStateDescription pci_vpb_vmstate = {
	.name = "versatile-pci",
	.version_id = 1,
	.minimum_version_id = 1,
	.post_load = pci_vpb_post_load,
	.fields = (VMStateField[]) {
	VMSTATE_UINT32_ARRAY(imap, PCIVPBState, 3),
	VMSTATE_UINT32_ARRAY(smap, PCIVPBState, 3),
	VMSTATE_UINT32(selfid, PCIVPBState),
	VMSTATE_UINT32(flags, PCIVPBState),
	VMSTATE_UINT8(irq_mapping, PCIVPBState),
	VMSTATE_END_OF_LIST()
	}
	};

	#define TYPE_VERSATILE_PCI "versatile_pci"
	DECLARE_INSTANCE_CHECKER(PCIVPBState, PCI_VPB,
	TYPE_VERSATILE_PCI)

	#define TYPE_VERSATILE_PCI_HOST "versatile_pci_host"
	DECLARE_INSTANCE_CHECKER(PCIDevice, PCI_VPB_HOST,
	TYPE_VERSATILE_PCI_HOST)

	typedef enum {
	PCI_IMAP0 = 0x0,
	PCI_IMAP1 = 0x4,
	PCI_IMAP2 = 0x8,
	PCI_SELFID = 0xc,
	PCI_FLAGS = 0x10,
	PCI_SMAP0 = 0x14,
	PCI_SMAP1 = 0x18,
	PCI_SMAP2 = 0x1c,
	} PCIVPBControlRegs;

	static void pci_vpb_reg_write(void *opaque, hwaddr addr,
	uint64_t val, unsigned size)
	{
	PCIVPBState *s = opaque;

	switch (addr) {
	case PCI_IMAP0:
	case PCI_IMAP1:
	case PCI_IMAP2:
	{
	int win = (addr - PCI_IMAP0) >> 2;
	s->imap[win] = val;
	pci_vpb_update_window(s, win);
	break;
	}
	case PCI_SELFID:
	s->selfid = val;
	break;
	case PCI_FLAGS:
	s->flags = val;
	break;
	case PCI_SMAP0:
	case PCI_SMAP1:
	case PCI_SMAP2:
	{
	int win = (addr - PCI_SMAP0) >> 2;
	s->smap[win] = val;
	break;
	}
	default:
	qemu_log_mask(LOG_GUEST_ERROR,
	"pci_vpb_reg_write: Bad offset %x\n", (int)addr);
	break;
	}
	}

	static uint64_t pci_vpb_reg_read(void *opaque, hwaddr addr,
	unsigned size)
	{
	PCIVPBState *s = opaque;

	switch (addr) {
	case PCI_IMAP0:
	case PCI_IMAP1:
	case PCI_IMAP2:
	{
	int win = (addr - PCI_IMAP0) >> 2;
	return s->imap[win];
	}
	case PCI_SELFID:
	return s->selfid;
	case PCI_FLAGS:
	return s->flags;
	case PCI_SMAP0:
	case PCI_SMAP1:
	case PCI_SMAP2:
	{
	int win = (addr - PCI_SMAP0) >> 2;
	return s->smap[win];
	}
	default:
	qemu_log_mask(LOG_GUEST_ERROR,
	"pci_vpb_reg_read: Bad offset %x\n", (int)addr);
	return 0;
	}
	}

	static const MemoryRegionOps pci_vpb_reg_ops = {
	.read = pci_vpb_reg_read,
	.write = pci_vpb_reg_write,
	.endianness = DEVICE_NATIVE_ENDIAN,
	.valid = {
	.min_access_size = 4,
	.max_access_size = 4,
	},
	};

	static int pci_vpb_broken_irq(int slot, int irq)
	{
	/* Determine whether this IRQ value for this slot represents a
	* known broken Linux kernel behaviour for this slot.
	* Return one of the PCI_VPB_IRQMAP_ constants:
	* BROKEN : if this definitely looks like a broken kernel
	* FORCE_OK : if this definitely looks good
	* ASSUME_OK : if we can't tell
	*/
	slot %= PCI_NUM_PINS;

	if (irq == 27) {
	if (slot == 2) {
	/* Might be a Phase I kernel, or might be a fixed kernel,
	* since slot 2 is where we expect this IRQ.
	*/
	return PCI_VPB_IRQMAP_ASSUME_OK;
	}
	/* Phase I kernel */
	return PCI_VPB_IRQMAP_BROKEN;
	}
	if (irq == slot + 27) {
	/* Phase II kernel */
	return PCI_VPB_IRQMAP_BROKEN;
	}
	if (irq == slot + 27 + 64) {
	/* Phase III kernel */
	return PCI_VPB_IRQMAP_BROKEN;
	}
	/* Anything else must be a fixed kernel, possibly using an
	* arbitrary irq map.
	*/
	return PCI_VPB_IRQMAP_FORCE_OK;
	}

	static void pci_vpb_config_write(void *opaque, hwaddr addr,
	uint64_t val, unsigned size)
	{
	PCIVPBState *s = opaque;
	if (!s->realview && (addr & 0xff) == PCI_INTERRUPT_LINE
	&& s->irq_mapping == PCI_VPB_IRQMAP_ASSUME_OK) {
	uint8_t devfn = addr >> 8;
	s->irq_mapping = pci_vpb_broken_irq(PCI_SLOT(devfn), val);
	}
	pci_data_write(&s->pci_bus, addr, val, size);
	}

	static uint64_t pci_vpb_config_read(void *opaque, hwaddr addr,
	unsigned size)
	{
	PCIVPBState *s = opaque;
	uint32_t val;
	val = pci_data_read(&s->pci_bus, addr, size);
	return val;
	}

	static const MemoryRegionOps pci_vpb_config_ops = {
	.read = pci_vpb_config_read,
	.write = pci_vpb_config_write,
	.endianness = DEVICE_NATIVE_ENDIAN,
	};

	static int pci_vpb_map_irq(PCIDevice *d, int irq_num)
	{
	PCIVPBState *s = container_of(pci_get_bus(d), PCIVPBState, pci_bus);

	if (s->irq_mapping == PCI_VPB_IRQMAP_BROKEN) {
	/* Legacy broken IRQ mapping for compatibility with old and
	* buggy Linux guests
	*/
	return irq_num;
	}

	/* Slot to IRQ mapping for RealView Platform Baseboard 926 backplane
	* name slot IntA IntB IntC IntD
	* A 31 IRQ28 IRQ29 IRQ30 IRQ27
	* B 30 IRQ27 IRQ28 IRQ29 IRQ30
	* C 29 IRQ30 IRQ27 IRQ28 IRQ29
	* Slot C is for the host bridge; A and B the peripherals.
	* Our output irqs 0..3 correspond to the baseboard's 27..30.
	*
	* This mapping function takes account of an oddity in the PB926
	* board wiring, where the FPGA's P_nINTA input is connected to
	* the INTB connection on the board PCI edge connector, P_nINTB
	* is connected to INTC, and so on, so everything is one number
	* further round from where you might expect.
	*/
	return pci_swizzle_map_irq_fn(d, irq_num + 2);
	}

	static int pci_vpb_rv_map_irq(PCIDevice *d, int irq_num)
	{
	/* Slot to IRQ mapping for RealView EB and PB1176 backplane
	* name slot IntA IntB IntC IntD
	* A 31 IRQ50 IRQ51 IRQ48 IRQ49
	* B 30 IRQ49 IRQ50 IRQ51 IRQ48
	* C 29 IRQ48 IRQ49 IRQ50 IRQ51
	* Slot C is for the host bridge; A and B the peripherals.
	* Our output irqs 0..3 correspond to the baseboard's 48..51.
	*
	* The PB1176 and EB boards don't have the PB926 wiring oddity
	* described above; P_nINTA connects to INTA, P_nINTB to INTB
	* and so on, which is why this mapping function is different.
	*/
	return pci_swizzle_map_irq_fn(d, irq_num + 3);
	}

	static void pci_vpb_set_irq(void *opaque, int irq_num, int level)
	{
	qemu_irq *pic = opaque;

	qemu_set_irq(pic[irq_num], level);
	}

	static void pci_vpb_reset(DeviceState *d)
	{
	PCIVPBState *s = PCI_VPB(d);

	s->imap[0] = 0;
	s->imap[1] = 0;
	s->imap[2] = 0;
	s->smap[0] = 0;
	s->smap[1] = 0;
	s->smap[2] = 0;
	s->selfid = 0;
	s->flags = 0;
	s->irq_mapping = s->irq_mapping_prop;

	pci_vpb_update_all_windows(s);
	}

	static void pci_vpb_init(Object *obj)
	{
	PCIVPBState *s = PCI_VPB(obj);

	/* Window sizes for VersatilePB; realview_pci's init will override */
	s->mem_win_size[0] = 0x0c000000;
	s->mem_win_size[1] = 0x10000000;
	s->mem_win_size[2] = 0x10000000;
	}

	static void pci_vpb_realize(DeviceState dev, Error *errp)
	{
	PCIVPBState *s = PCI_VPB(dev);
	PCIHostState *h = PCI_HOST_BRIDGE(dev);
	SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
	pci_map_irq_fn mapfn;
	int i;

	memory_region_init(&s->pci_io_space, OBJECT(s), "pci_io", 4 * GiB);
	memory_region_init(&s->pci_mem_space, OBJECT(s), "pci_mem", 4 * GiB);

	pci_root_bus_init(&s->pci_bus, sizeof(s->pci_bus), dev, "pci",
	&s->pci_mem_space, &s->pci_io_space,
	PCI_DEVFN(11, 0), TYPE_PCI_BUS);
	h->bus = &s->pci_bus;

	object_initialize(&s->pci_dev, sizeof(s->pci_dev), TYPE_VERSATILE_PCI_HOST);

	for (i = 0; i < 4; i++) {
	sysbus_init_irq(sbd, &s->irq[i]);
	}

	if (s->realview) {
	mapfn = pci_vpb_rv_map_irq;
	} else {
	mapfn = pci_vpb_map_irq;
	}

	pci_bus_irqs(&s->pci_bus, pci_vpb_set_irq, s->irq, 4);
	pci_bus_map_irqs(&s->pci_bus, mapfn);

	/* Our memory regions are:
	* 0 : our control registers
	* 1 : PCI self config window
	* 2 : PCI config window
	* 3 : PCI IO window
	* 4..6 : PCI memory windows
	*/
	memory_region_init_io(&s->controlregs, OBJECT(s), &pci_vpb_reg_ops, s,
	"pci-vpb-regs", 0x1000);
	sysbus_init_mmio(sbd, &s->controlregs);
	memory_region_init_io(&s->mem_config, OBJECT(s), &pci_vpb_config_ops, s,
	"pci-vpb-selfconfig", 0x1000000);
	sysbus_init_mmio(sbd, &s->mem_config);
	memory_region_init_io(&s->mem_config2, OBJECT(s), &pci_vpb_config_ops, s,
	"pci-vpb-config", 0x1000000);
	sysbus_init_mmio(sbd, &s->mem_config2);

	/* The window into I/O space is always into a fixed base address;
	* its size is the same for both realview and versatile.
	*/
	memory_region_init_alias(&s->pci_io_window, OBJECT(s), "pci-vbp-io-window",
	&s->pci_io_space, 0, 0x100000);

	sysbus_init_mmio(sbd, &s->pci_io_space);

	/* Create the alias regions corresponding to our three windows onto
	* PCI memory space. The sizes vary from board to board; the base
	* offsets are guest controllable via the IMAP registers.
	*/
	for (i = 0; i < 3; i++) {
	memory_region_init_alias(&s->pci_mem_window[i], OBJECT(s), "pci-vbp-window",
	&s->pci_mem_space, 0, s->mem_win_size[i]);
	sysbus_init_mmio(sbd, &s->pci_mem_window[i]);
	}

	/* TODO Remove once realize propagates to child devices. */
	qdev_realize(DEVICE(&s->pci_dev), BUS(&s->pci_bus), errp);
	}

	static void versatile_pci_host_realize(PCIDevice d, Error *errp)
	{
	pci_set_word(d->config + PCI_STATUS,
	PCI_STATUS_66MHZ \| PCI_STATUS_DEVSEL_MEDIUM);
	pci_set_byte(d->config + PCI_LATENCY_TIMER, 0x10);
	}

	static void versatile_pci_host_class_init(ObjectClass klass, void data)
	{
	PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
	DeviceClass *dc = DEVICE_CLASS(klass);

	k->realize = versatile_pci_host_realize;
	k->vendor_id = PCI_VENDOR_ID_XILINX;
	k->device_id = PCI_DEVICE_ID_XILINX_XC2VP30;
	k->class_id = PCI_CLASS_PROCESSOR_CO;
	/*
	* PCI-facing part of the host bridge, not usable without the
	* host-facing part, which can't be device_add'ed, yet.
	*/
	dc->user_creatable = false;
	}

	static const TypeInfo versatile_pci_host_info = {
	.name = TYPE_VERSATILE_PCI_HOST,
	.parent = TYPE_PCI_DEVICE,
	.instance_size = sizeof(PCIDevice),
	.class_init = versatile_pci_host_class_init,
	.interfaces = (InterfaceInfo[]) {
	{ INTERFACE_CONVENTIONAL_PCI_DEVICE },
	{ },
	},
	};

	static Property pci_vpb_properties[] = {
	DEFINE_PROP_UINT8("broken-irq-mapping", PCIVPBState, irq_mapping_prop,
	PCI_VPB_IRQMAP_ASSUME_OK),
	DEFINE_PROP_END_OF_LIST()
	};

	static void pci_vpb_class_init(ObjectClass klass, void data)
	{
	DeviceClass *dc = DEVICE_CLASS(klass);

	dc->realize = pci_vpb_realize;
	dc->reset = pci_vpb_reset;
	dc->vmsd = &pci_vpb_vmstate;
	device_class_set_props(dc, pci_vpb_properties);
	}

	static const TypeInfo pci_vpb_info = {
	.name = TYPE_VERSATILE_PCI,
	.parent = TYPE_PCI_HOST_BRIDGE,
	.instance_size = sizeof(PCIVPBState),
	.instance_init = pci_vpb_init,
	.class_init = pci_vpb_class_init,
	};

	static void pci_realview_init(Object *obj)
	{
	PCIVPBState *s = PCI_VPB(obj);

	s->realview = 1;
	/* The PCI window sizes are different on Realview boards */
	s->mem_win_size[0] = 0x01000000;
	s->mem_win_size[1] = 0x04000000;
	s->mem_win_size[2] = 0x08000000;
	}

	static const TypeInfo pci_realview_info = {
	.name = "realview_pci",
	.parent = TYPE_VERSATILE_PCI,
	.instance_init = pci_realview_init,
	};

	static void versatile_pci_register_types(void)
	{
	type_register_static(&pci_vpb_info);
	type_register_static(&pci_realview_info);
	type_register_static(&versatile_pci_host_info);
	}

	type_init(versatile_pci_register_types)