/* 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..
*/
void
pcibios_align_resource(void *data, struct resource *res,
resource_size_t size, resource_size_t align)
{
if (res->flags & IORESOURCE_IO) {
resource_size_t start = res->start;
if (start & 0x300) {
start = (start + 0x3ff) & ~0x3ff;
res->start = 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, *pr;
/* 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;
pr = pci_find_parent_resource(dev, r);
if (!pr || request_resource(pr, r) < 0)
printk(KERN_ERR "PCI: Cannot allocate resource region %d of bridge %s\n", idx, pci_name(dev));
}
}
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, *pr;
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)\n",
r->start, r->end, r->flags, disabled, pass);
pr = pci_find_parent_resource(dev, r);
if (!pr || request_resource(pr, r) < 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 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\n");
pcibios_allocate_bus_resources(&pci_root_buses);
pcibios_allocate_resources(0);
pcibios_allocate_resources(1);
pcibios_assign_resources();
}
/*
* If we set up a device for bus mastering, we need to check the latency
* timer as certain crappy BIOSes forget to set it properly.
*/
unsigned int pcibios_max_latency = 255;
void pcibios_set_master(struct pci_dev *dev)
{
u8 lat;
pci_read_config_byte(dev, PCI_LATENCY_TIMER, &lat);
if (lat < 16)
lat = (64 <= pcibios_max_latency) ? 64 : pcibios_max_latency;
else if (lat > pcibios_max_latency)
lat = pcibios_max_latency;
else
return;
printk(KERN_DEBUG "PCI: Setting latency timer of device %s to %d\n", pci_name(dev), lat);
pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat);
}
