#include <linux/export.h>
  #include <linux/kernel.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  
  #include <asm/addrspace.h>
  #include <asm/paccess.h>
  #include <asm/gio_device.h>
  #include <asm/sgi/gio.h>
  #include <asm/sgi/hpc3.h>
  #include <asm/sgi/mc.h>
  #include <asm/sgi/ip22.h>
  
  static struct bus_type gio_bus_type;
  
  static struct {
  	const char *name;
  	__u8	   id;
  } gio_name_table[] = {
  	{ .name = "SGI Impact", .id = 0x10 },
  	{ .name = "Phobos G160", .id = 0x35 },
  	{ .name = "Phobos G130", .id = 0x36 },
  	{ .name = "Phobos G100", .id = 0x37 },
  	{ .name = "Set Engineering GFE", .id = 0x38 },
  	/* fake IDs */
  	{ .name = "SGI Newport", .id = 0x7e },
  	{ .name = "SGI GR2/GR3", .id = 0x7f },
  };
  
  static void gio_bus_release(struct device *dev)
  {
  	kfree(dev);
  }
  
  static struct device gio_bus = {
  	.init_name = "gio",
  	.release = &gio_bus_release,
  };
  
  /**
   * gio_match_device - Tell if an of_device structure has a matching
   * gio_match structure
   * @ids: array of of device match structures to search in
   * @dev: the of device structure to match against
   *
   * Used by a driver to check whether an of_device present in the
   * system is in its list of supported devices.
   */
  const struct gio_device_id *gio_match_device(const struct gio_device_id *match,
  		     const struct gio_device *dev)
  {
  	const struct gio_device_id *ids;
  
  	for (ids = match; ids->id != 0xff; ids++)
  		if (ids->id == dev->id.id)
  			return ids;
  
  	return NULL;
  }
  EXPORT_SYMBOL_GPL(gio_match_device);
  
  struct gio_device *gio_dev_get(struct gio_device *dev)
  {
  	struct device *tmp;
  
  	if (!dev)
  		return NULL;
  	tmp = get_device(&dev->dev);
  	if (tmp)
  		return to_gio_device(tmp);
  	else
  		return NULL;
  }
  EXPORT_SYMBOL_GPL(gio_dev_get);
  
  void gio_dev_put(struct gio_device *dev)
  {
  	if (dev)
  		put_device(&dev->dev);
  }
  EXPORT_SYMBOL_GPL(gio_dev_put);
  
  /**
   * gio_release_dev - free an gio device structure when all users of it are finished.
   * @dev: device that's been disconnected
   *
   * Will be called only by the device core when all users of this gio device are
   * done.
   */
  void gio_release_dev(struct device *dev)
  {
  	struct gio_device *giodev;
  
  	giodev = to_gio_device(dev);
  	kfree(giodev);
  }
  EXPORT_SYMBOL_GPL(gio_release_dev);
  
  int gio_device_register(struct gio_device *giodev)
  {
  	giodev->dev.bus = &gio_bus_type;
  	giodev->dev.parent = &gio_bus;
  	return device_register(&giodev->dev);
  }
  EXPORT_SYMBOL_GPL(gio_device_register);
  
  void gio_device_unregister(struct gio_device *giodev)
  {
  	device_unregister(&giodev->dev);
  }
  EXPORT_SYMBOL_GPL(gio_device_unregister);
  
  static int gio_bus_match(struct device *dev, struct device_driver *drv)
  {
  	struct gio_device *gio_dev = to_gio_device(dev);
  	struct gio_driver *gio_drv = to_gio_driver(drv);
  
  	return gio_match_device(gio_drv->id_table, gio_dev) != NULL;
  }
  
  static int gio_device_probe(struct device *dev)
  {
  	int error = -ENODEV;
  	struct gio_driver *drv;
  	struct gio_device *gio_dev;
  	const struct gio_device_id *match;
  
  	drv = to_gio_driver(dev->driver);
  	gio_dev = to_gio_device(dev);
  
  	if (!drv->probe)
  		return error;
  
  	gio_dev_get(gio_dev);
  
  	match = gio_match_device(drv->id_table, gio_dev);
  	if (match)
  		error = drv->probe(gio_dev, match);
  	if (error)
  		gio_dev_put(gio_dev);
  
  	return error;
  }
  
  static int gio_device_remove(struct device *dev)
  {
  	struct gio_device *gio_dev = to_gio_device(dev);
  	struct gio_driver *drv = to_gio_driver(dev->driver);
  
  	if (dev->driver && drv->remove)
  		drv->remove(gio_dev);
  	return 0;
  }
  
  static void gio_device_shutdown(struct device *dev)
  {
  	struct gio_device *gio_dev = to_gio_device(dev);
  	struct gio_driver *drv = to_gio_driver(dev->driver);
  
  	if (dev->driver && drv->shutdown)
  		drv->shutdown(gio_dev);
  }
  
  static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
  			     char *buf)
  {
  	struct gio_device *gio_dev = to_gio_device(dev);
  	int len = snprintf(buf, PAGE_SIZE, "gio:%x
  ", gio_dev->id.id);
  
  	return (len >= PAGE_SIZE) ? (PAGE_SIZE - 1) : len;
  }
  
  static ssize_t name_show(struct device *dev,
  			 struct device_attribute *attr, char *buf)
  {
  	struct gio_device *giodev;
  
  	giodev = to_gio_device(dev);
  	return sprintf(buf, "%s", giodev->name);
  }
  
  static ssize_t id_show(struct device *dev,
  		       struct device_attribute *attr, char *buf)
  {
  	struct gio_device *giodev;
  
  	giodev = to_gio_device(dev);
  	return sprintf(buf, "%x", giodev->id.id);
  }
  
  static struct device_attribute gio_dev_attrs[] = {
  	__ATTR_RO(modalias),
  	__ATTR_RO(name),
  	__ATTR_RO(id),
  	__ATTR_NULL,
  };
  
  static int gio_device_uevent(struct device *dev, struct kobj_uevent_env *env)
  {
  	struct gio_device *gio_dev = to_gio_device(dev);
  
  	add_uevent_var(env, "MODALIAS=gio:%x", gio_dev->id.id);
  	return 0;
  }
  
  int gio_register_driver(struct gio_driver *drv)
  {
  	/* initialize common driver fields */
  	if (!drv->driver.name)
  		drv->driver.name = drv->name;
  	if (!drv->driver.owner)
  		drv->driver.owner = drv->owner;
  	drv->driver.bus = &gio_bus_type;
  
  	/* register with core */
  	return driver_register(&drv->driver);
  }
  EXPORT_SYMBOL_GPL(gio_register_driver);
  
  void gio_unregister_driver(struct gio_driver *drv)
  {
  	driver_unregister(&drv->driver);
  }
  EXPORT_SYMBOL_GPL(gio_unregister_driver);
  
  void gio_set_master(struct gio_device *dev)
  {
  	u32 tmp = sgimc->giopar;
  
  	switch (dev->slotno) {
  	case 0:
  		tmp |= SGIMC_GIOPAR_MASTERGFX;
  		break;
  	case 1:
  		tmp |= SGIMC_GIOPAR_MASTEREXP0;
  		break;
  	case 2:
  		tmp |= SGIMC_GIOPAR_MASTEREXP1;
  		break;
  	}
  	sgimc->giopar = tmp;
  }
  EXPORT_SYMBOL_GPL(gio_set_master);
  
  void ip22_gio_set_64bit(int slotno)
  {
  	u32 tmp = sgimc->giopar;
  
  	switch (slotno) {
  	case 0:
  		tmp |= SGIMC_GIOPAR_GFX64;
  		break;
  	case 1:
  		tmp |= SGIMC_GIOPAR_EXP064;
  		break;
  	case 2:
  		tmp |= SGIMC_GIOPAR_EXP164;
  		break;
  	}
  	sgimc->giopar = tmp;
  }
  
  static int ip22_gio_id(unsigned long addr, u32 *res)
  {
  	u8 tmp8;
  	u8 tmp16;
  	u32 tmp32;
  	u8 *ptr8;
  	u16 *ptr16;
  	u32 *ptr32;
  
  	ptr32 = (void *)CKSEG1ADDR(addr);
  	if (!get_dbe(tmp32, ptr32)) {
  		/*
  		 * We got no DBE, but this doesn't mean anything.
  		 * If GIO is pipelined (which can't be disabled
  		 * for GFX slot) we don't get a DBE, but we see
  		 * the transfer size as data. So we do an 8bit
  		 * and a 16bit access and check whether the common
  		 * data matches
  		 */
  		ptr8 = (void *)CKSEG1ADDR(addr + 3);
  		if (get_dbe(tmp8, ptr8)) {
  			/*
  			 * 32bit access worked, but 8bit doesn't
  			 * so we don't see phantom reads on
  			 * a pipelined bus, but a real card which
  			 * doesn't support 8 bit reads
  			 */
  			*res = tmp32;
  			return 1;
  		}
  		ptr16 = (void *)CKSEG1ADDR(addr + 2);
  		get_dbe(tmp16, ptr16);
  		if (tmp8 == (tmp16 & 0xff) &&
  		    tmp8 == (tmp32 & 0xff) &&
  		    tmp16 == (tmp32 & 0xffff)) {
  			*res = tmp32;
  			return 1;
  		}
  	}
  	return 0; /* nothing here */
  }
  
  #define HQ2_MYSTERY_OFFS       0x6A07C
  #define NEWPORT_USTATUS_OFFS   0xF133C
  
  static int ip22_is_gr2(unsigned long addr)
  {
  	u32 tmp;
  	u32 *ptr;
  
  	/* HQ2 only allows 32bit accesses */
  	ptr = (void *)CKSEG1ADDR(addr + HQ2_MYSTERY_OFFS);
  	if (!get_dbe(tmp, ptr)) {
  		if (tmp == 0xdeadbeef)
  			return 1;
  	}
  	return 0;
  }
  
  
  static void ip22_check_gio(int slotno, unsigned long addr, int irq)
  {
  	const char *name = "Unknown";
  	struct gio_device *gio_dev;
  	u32 tmp;
  	__u8 id;
  	int i;
  
  	/* first look for GR2/GR3 by checking mystery register */
  	if (ip22_is_gr2(addr))
  		tmp = 0x7f;
  	else {
  		if (!ip22_gio_id(addr, &tmp)) {
  			/*
  			 * no GIO signature at start address of slot
  			 * since Newport doesn't have one, we check if
  			 * user status register is readable
  			 */
  			if (ip22_gio_id(addr + NEWPORT_USTATUS_OFFS, &tmp))
  				tmp = 0x7e;
  			else
  				tmp = 0;
  		}
  	}
  	if (tmp) {
  		id = GIO_ID(tmp);
  		if (tmp & GIO_32BIT_ID) {
  			if (tmp & GIO_64BIT_IFACE)
  				ip22_gio_set_64bit(slotno);
  		}
  		for (i = 0; i < ARRAY_SIZE(gio_name_table); i++) {
  			if (id == gio_name_table[i].id) {
  				name = gio_name_table[i].name;
  				break;
  			}
  		}
  		printk(KERN_INFO "GIO: slot %d : %s (id %x)
  ",
  		       slotno, name, id);
  		gio_dev = kzalloc(sizeof *gio_dev, GFP_KERNEL);
  		gio_dev->name = name;
  		gio_dev->slotno = slotno;
  		gio_dev->id.id = id;
  		gio_dev->resource.start = addr;
  		gio_dev->resource.end = addr + 0x3fffff;
  		gio_dev->resource.flags = IORESOURCE_MEM;
  		gio_dev->irq = irq;
  		dev_set_name(&gio_dev->dev, "%d", slotno);
  		gio_device_register(gio_dev);
  	} else
  		printk(KERN_INFO "GIO: slot %d : Empty
  ", slotno);
  }
  
  static struct bus_type gio_bus_type = {
  	.name	   = "gio",
  	.dev_attrs = gio_dev_attrs,
  	.match	   = gio_bus_match,
  	.probe	   = gio_device_probe,
  	.remove	   = gio_device_remove,
  	.shutdown  = gio_device_shutdown,
  	.uevent	   = gio_device_uevent,
  };
  
  static struct resource gio_bus_resource = {
  	.start = GIO_SLOT_GFX_BASE,
  	.end   = GIO_SLOT_GFX_BASE + 0x9fffff,
  	.name  = "GIO Bus",
  	.flags = IORESOURCE_MEM,
  };
  
  int __init ip22_gio_init(void)
  {
  	unsigned int pbdma __maybe_unused;
  	int ret;
  
  	ret = device_register(&gio_bus);
  	if (ret) {
  		put_device(&gio_bus);
  		return ret;
  	}
  
  	ret = bus_register(&gio_bus_type);
  	if (!ret) {
  		request_resource(&iomem_resource, &gio_bus_resource);
  		printk(KERN_INFO "GIO: Probing bus...
  ");
  
  		if (ip22_is_fullhouse()) {
  			/* Indigo2 */
  			ip22_check_gio(0, GIO_SLOT_GFX_BASE, SGI_GIO_1_IRQ);
  			ip22_check_gio(1, GIO_SLOT_EXP0_BASE, SGI_GIO_1_IRQ);
  		} else {
  			/* Indy/Challenge S */
  			if (get_dbe(pbdma, (unsigned int *)&hpc3c1->pbdma[1]))
  				ip22_check_gio(0, GIO_SLOT_GFX_BASE,
  					       SGI_GIO_0_IRQ);
  			ip22_check_gio(1, GIO_SLOT_EXP0_BASE, SGI_GIOEXP0_IRQ);
  			ip22_check_gio(2, GIO_SLOT_EXP1_BASE, SGI_GIOEXP1_IRQ);
  		}
  	} else
  		device_unregister(&gio_bus);
  
  	return ret;
  }
  
  subsys_initcall(ip22_gio_init);