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/* ASB2305 PCI resource stuff
*
* Copyright (C) 2001 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
* - Derived from arch/i386/pci-i386.c
* - Copyright 1997--2000 Martin Mares <mj@suse.cz>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, 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-asb2305.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 0
struct pci_dev *dev = data;
printk(KERN_DEBUG
"### PCIBIOS_ALIGN_RESOURCE(%s,,{%08lx-%08lx,%08lx},%lx)\n",
pci_name(dev),
res->start,
res->end,
res->flags,
size
);
#endif
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 pci_bus *bus;
struct pci_dev *dev;
int idx;
struct resource *r;
/* Depth-First Search on bus tree */
list_for_each_entry(bus, bus_list, node) {
dev = bus->self;
if (dev) {
for (idx = PCI_BRIDGE_RESOURCES;
idx < PCI_NUM_RESOURCES;
idx++) {
r = &dev->resource[idx];
if (!r->flags)
continue;
if (!r->start ||
pci_claim_bridge_resource(dev, idx) < 0) {
printk(KERN_ERR "PCI:"
" Cannot allocate resource"
" region %d of bridge %s\n",
idx, pci_name(dev));
/* Something is wrong with the region.
* Invalidate the resource to prevent
* child resource allocations in this
* range. */
r->start = r->end = 0;
r->flags = 0;
}
}
}
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 */
continue;
if (r->flags & IORESOURCE_IO)
disabled = !(command & PCI_COMMAND_IO);
else
disabled = !(command & PCI_COMMAND_MEMORY);
if (pass == disabled) {
DBG("PCI[%s]: Resource %08lx-%08lx"
" (f=%lx, d=%d, p=%d)\n",
pci_name(dev), r->start, r->end, r->flags,
disabled, pass);
if (pci_claim_resource(dev, idx) < 0) {
printk(KERN_ERR "PCI:"
" Cannot allocate resource"
" region %d of device %s\n",
idx, pci_name(dev));
/* 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\n",
pci_name(dev));
r->flags &= ~IORESOURCE_ROM_ENABLE;
pci_read_config_dword(
dev, dev->rom_base_reg, ®);
pci_write_config_dword(
dev, dev->rom_base_reg,
reg & ~PCI_ROM_ADDRESS_ENABLE);
}
}
}
}
static int __init pcibios_assign_resources(void)
{
struct pci_dev *dev = NULL;
struct resource *r;
/* Try to use BIOS settings for ROMs, otherwise let
pci_assign_unassigned_resources() allocate the new
addresses. */
for_each_pci_dev(dev) {
r = &dev->resource[PCI_ROM_RESOURCE];
if (!r->flags || !r->start)
continue;
if (pci_claim_resource(dev, PCI_ROM_RESOURCE) < 0) {
r->end -= r->start;
r->start = 0;
}
}
pci_assign_unassigned_resources();
return 0;
}
fs_initcall(pcibios_assign_resources);
void __init pcibios_resource_survey(void)
{
DBG("PCI: Allocating resources\n");
pcibios_allocate_bus_resources(&pci_root_buses);
pcibios_allocate_resources(0);
pcibios_allocate_resources(1);
}
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