/******************************************************************************
   * platform-pci-unplug.c
   *
   * Xen platform PCI device driver
   * Copyright (c) 2010, Citrix
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms and conditions of the GNU General Public License,
   * version 2, as published by the Free Software Foundation.
   *
   * This program is distributed in the hope 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/init.h>
  #include <linux/io.h>
  #include <linux/module.h>
  
  #include <xen/platform_pci.h>
  
  #define XEN_PLATFORM_ERR_MAGIC -1
  #define XEN_PLATFORM_ERR_PROTOCOL -2
  #define XEN_PLATFORM_ERR_BLACKLIST -3
  
  /* store the value of xen_emul_unplug after the unplug is done */
  int xen_platform_pci_unplug;
  EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);

  #ifdef CONFIG_XEN_PVHVM

  static int xen_emul_unplug;

  static int check_platform_magic(void)

  {
  	short magic;
  	char protocol;
  
  	magic = inw(XEN_IOPORT_MAGIC);
  	if (magic != XEN_IOPORT_MAGIC_VAL) {
  		printk(KERN_ERR "Xen Platform PCI: unrecognised magic value
  ");
  		return XEN_PLATFORM_ERR_MAGIC;
  	}
  
  	protocol = inb(XEN_IOPORT_PROTOVER);
  
  	printk(KERN_DEBUG "Xen Platform PCI: I/O protocol version %d
  ",
  			protocol);
  
  	switch (protocol) {
  	case 1:
  		outw(XEN_IOPORT_LINUX_PRODNUM, XEN_IOPORT_PRODNUM);
  		outl(XEN_IOPORT_LINUX_DRVVER, XEN_IOPORT_DRVVER);
  		if (inw(XEN_IOPORT_MAGIC) != XEN_IOPORT_MAGIC_VAL) {
  			printk(KERN_ERR "Xen Platform: blacklisted by host
  ");
  			return XEN_PLATFORM_ERR_BLACKLIST;
  		}
  		break;
  	default:
  		printk(KERN_WARNING "Xen Platform PCI: unknown I/O protocol version");
  		return XEN_PLATFORM_ERR_PROTOCOL;
  	}
  
  	return 0;
  }

  void xen_unplug_emulated_devices(void)

  {
  	int r;

  	/* user explicitly requested no unplug */
  	if (xen_emul_unplug & XEN_UNPLUG_NEVER)
  		return;

  	/* check the version of the xen platform PCI device */
  	r = check_platform_magic();
  	/* If the version matches enable the Xen platform PCI driver.

  	 * Also enable the Xen platform PCI driver if the host does
  	 * not support the unplug protocol (XEN_PLATFORM_ERR_MAGIC)
  	 * but the user told us that unplugging is unnecessary. */

  	if (r && !(r == XEN_PLATFORM_ERR_MAGIC &&

  			(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY)))

  		return;
  	/* Set the default value of xen_emul_unplug depending on whether or
  	 * not the Xen PV frontends and the Xen platform PCI driver have
  	 * been compiled for this kernel (modules or built-in are both OK). */
  	if (!xen_emul_unplug) {
  		if (xen_must_unplug_nics()) {
  			printk(KERN_INFO "Netfront and the Xen platform PCI driver have "
  					"been compiled for this kernel: unplug emulated NICs.
  ");
  			xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
  		}
  		if (xen_must_unplug_disks()) {
  			printk(KERN_INFO "Blkfront and the Xen platform PCI driver have "
  					"been compiled for this kernel: unplug emulated disks.
  "
  					"You might have to change the root device
  "
  					"from /dev/hd[a-d] to /dev/xvd[a-d]
  "
  					"in your root= kernel command line option
  ");
  			xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
  		}
  	}
  	/* Now unplug the emulated devices */

  	if (!(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY))

  		outw(xen_emul_unplug, XEN_IOPORT_UNPLUG);
  	xen_platform_pci_unplug = xen_emul_unplug;
  }
  
  static int __init parse_xen_emul_unplug(char *arg)
  {
  	char *p, *q;
  	int l;
  
  	for (p = arg; p; p = q) {
  		q = strchr(p, ',');
  		if (q) {
  			l = q - p;
  			q++;
  		} else {
  			l = strlen(p);
  		}
  		if (!strncmp(p, "all", l))
  			xen_emul_unplug |= XEN_UNPLUG_ALL;
  		else if (!strncmp(p, "ide-disks", l))
  			xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
  		else if (!strncmp(p, "aux-ide-disks", l))
  			xen_emul_unplug |= XEN_UNPLUG_AUX_IDE_DISKS;
  		else if (!strncmp(p, "nics", l))
  			xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;

  		else if (!strncmp(p, "unnecessary", l))
  			xen_emul_unplug |= XEN_UNPLUG_UNNECESSARY;

  		else if (!strncmp(p, "never", l))
  			xen_emul_unplug |= XEN_UNPLUG_NEVER;

  		else
  			printk(KERN_WARNING "unrecognised option '%s' "
  				 "in parameter 'xen_emul_unplug'
  ", p);
  	}
  	return 0;
  }
  early_param("xen_emul_unplug", parse_xen_emul_unplug);

  #endif