/* pci-frv.c: low-level PCI access routines
   *
   * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
   * Written by David Howells (dhowells@redhat.com)
   * - Derived from the i386 equivalent stuff
   *
   * 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.
   */
  
  #include <linux/types.h>
  #include <linux/kernel.h>
  #include <linux/pci.h>
  #include <linux/init.h>
  #include <linux/ioport.h>
  #include <linux/errno.h>
  
  #include "pci-frv.h"
  
  /*
   * We need to avoid collisions with `mirrored' VGA ports
   * and other strange ISA hardware, so we always want the
   * addresses to be allocated in the 0x000-0x0ff region
   * modulo 0x400.
   *
   * Why? Because some silly external IO cards only decode
   * the low 10 bits of the IO address. The 0x00-0xff region
   * is reserved for motherboard devices that decode all 16
   * bits, so it's ok to allocate at, say, 0x2800-0x28ff,
   * but we want to try to avoid allocating at 0x2900-0x2bff
   * which might have be mirrored at 0x0100-0x03ff..
   */
  resource_size_t
  pcibios_align_resource(void *data, const struct resource *res,
  		       resource_size_t size, resource_size_t align)
  {
  	resource_size_t start = res->start;
  
  	if ((res->flags & IORESOURCE_IO) && (start & 0x300))
  		start = (start + 0x3ff) & ~0x3ff;
  
  	return start;
  }
  
  
  /*
   *  Handle resources of PCI devices.  If the world were perfect, we could
   *  just allocate all the resource regions and do nothing more.  It isn't.
   *  On the other hand, we cannot just re-allocate all devices, as it would
   *  require us to know lots of host bridge internals.  So we attempt to
   *  keep as much of the original configuration as possible, but tweak it
   *  when it's found to be wrong.
   *
   *  Known BIOS problems we have to work around:
   *	- I/O or memory regions not configured
   *	- regions configured, but not enabled in the command register
   *	- bogus I/O addresses above 64K used
   *	- expansion ROMs left enabled (this may sound harmless, but given
   *	  the fact the PCI specs explicitly allow address decoders to be
   *	  shared between expansion ROMs and other resource regions, it's
   *	  at least dangerous)
   *
   *  Our solution:
   *	(1) Allocate resources for all buses behind PCI-to-PCI bridges.
   *	    This gives us fixed barriers on where we can allocate.
   *	(2) Allocate resources for all enabled devices.  If there is
   *	    a collision, just mark the resource as unallocated. Also
   *	    disable expansion ROMs during this step.
   *	(3) Try to allocate resources for disabled devices.  If the
   *	    resources were assigned correctly, everything goes well,
   *	    if they weren't, they won't disturb allocation of other
   *	    resources.
   *	(4) Assign new addresses to resources which were either
   *	    not configured at all or misconfigured.  If explicitly
   *	    requested by the user, configure expansion ROM address
   *	    as well.
   */
  
  static void __init pcibios_allocate_bus_resources(struct list_head *bus_list)
  {
  	struct list_head *ln;
  	struct pci_bus *bus;
  	struct pci_dev *dev;
  	int idx;
  	struct resource *r;
  
  	/* Depth-First Search on bus tree */
  	for (ln=bus_list->next; ln != bus_list; ln=ln->next) {
  		bus = pci_bus_b(ln);
  		if ((dev = bus->self)) {
  			for (idx = PCI_BRIDGE_RESOURCES; idx < PCI_NUM_RESOURCES; idx++) {
  				r = &dev->resource[idx];
  				if (!r->start)
  					continue;
  				pci_claim_resource(dev, idx);
  			}
  		}
  		pcibios_allocate_bus_resources(&bus->children);
  	}
  }
  
  static void __init pcibios_allocate_resources(int pass)
  {
  	struct pci_dev *dev = NULL;
  	int idx, disabled;
  	u16 command;
  	struct resource *r;
  
  	for_each_pci_dev(dev) {
  		pci_read_config_word(dev, PCI_COMMAND, &command);
  		for(idx = 0; idx < 6; idx++) {
  			r = &dev->resource[idx];
  			if (r->parent)		/* Already allocated */
  				continue;
  			if (!r->start)		/* Address not assigned at all */
  				continue;
  			if (r->flags & IORESOURCE_IO)
  				disabled = !(command & PCI_COMMAND_IO);
  			else
  				disabled = !(command & PCI_COMMAND_MEMORY);
  			if (pass == disabled) {
  				DBG("PCI: Resource %08lx-%08lx (f=%lx, d=%d, p=%d)
  ",
  				    r->start, r->end, r->flags, disabled, pass);
  				if (pci_claim_resource(dev, idx) < 0) {
  					/* We'll assign a new address later */
  					r->end -= r->start;
  					r->start = 0;
  				}
  			}
  		}
  		if (!pass) {
  			r = &dev->resource[PCI_ROM_RESOURCE];
  			if (r->flags & IORESOURCE_ROM_ENABLE) {
  				/* Turn the ROM off, leave the resource region, but keep it unregistered. */
  				u32 reg;
  				DBG("PCI: Switching off ROM of %s
  ", pci_name(dev));
  				r->flags &= ~IORESOURCE_ROM_ENABLE;
  				pci_read_config_dword(dev, dev->rom_base_reg, &reg);
  				pci_write_config_dword(dev, dev->rom_base_reg, reg & ~PCI_ROM_ADDRESS_ENABLE);
  			}
  		}
  	}
  }
  
  static void __init pcibios_assign_resources(void)
  {
  	struct pci_dev *dev = NULL;
  	int idx;
  	struct resource *r;
  
  	for_each_pci_dev(dev) {
  		int class = dev->class >> 8;
  
  		/* Don't touch classless devices and host bridges */
  		if (!class || class == PCI_CLASS_BRIDGE_HOST)
  			continue;
  
  		for(idx=0; idx<6; idx++) {
  			r = &dev->resource[idx];
  
  			/*
  			 *  Don't touch IDE controllers and I/O ports of video cards!
  			 */
  			if ((class == PCI_CLASS_STORAGE_IDE && idx < 4) ||
  			    (class == PCI_CLASS_DISPLAY_VGA && (r->flags & IORESOURCE_IO)))
  				continue;
  
  			/*
  			 *  We shall assign a new address to this resource, either because
  			 *  the BIOS forgot to do so or because we have decided the old
  			 *  address was unusable for some reason.
  			 */
  			if (!r->start && r->end)
  				pci_assign_resource(dev, idx);
  		}
  
  		if (pci_probe & PCI_ASSIGN_ROMS) {
  			r = &dev->resource[PCI_ROM_RESOURCE];
  			r->end -= r->start;
  			r->start = 0;
  			if (r->end)
  				pci_assign_resource(dev, PCI_ROM_RESOURCE);
  		}
  	}
  }
  
  void __init pcibios_resource_survey(void)
  {
  	DBG("PCI: Allocating resources
  ");
  	pcibios_allocate_bus_resources(&pci_root_buses);
  	pcibios_allocate_resources(0);
  	pcibios_allocate_resources(1);
  	pcibios_assign_resources();
  }