/*
* Low-Level PCI Access for i386 machines
*
* Copyright 1993, 1994 Drew Eckhardt
* Visionary Computing
* (Unix and Linux consulting and custom programming)
* Drew@Colorado.EDU
* +1 (303) 786-7975
*
* Drew's work was sponsored by:
* iX Multiuser Multitasking Magazine
* Hannover, Germany
* hm@ix.de
*
* Copyright 1997--2000 Martin Mares <mj@suse.cz>
*
* For more information, please consult the following manuals (look at
* http://www.pcisig.com/ for how to get them):
*
* PCI BIOS Specification
* PCI Local Bus Specification
* PCI to PCI Bridge Specification
* PCI System Design Guide
*
*
* CHANGELOG :
* Jun 17, 1994 : Modified to accommodate the broken pre-PCI BIOS SPECIFICATION
* Revision 2.0 present on <thys@dennis.ee.up.ac.za>'s ASUS mainboard.
*
* Jan 5, 1995 : Modified to probe PCI hardware at boot time by Frederic
* Potter, potter@cao-vlsi.ibp.fr
*
* Jan 10, 1995 : Modified to store the information about configured pci
* devices into a list, which can be accessed via /proc/pci by
* Curtis Varner, cvarner@cs.ucr.edu
*
* Jan 12, 1995 : CPU-PCI bridge optimization support by Frederic Potter.
* Alpha version. Intel & UMC chipset support only.
*
* Apr 16, 1995 : Source merge with the DEC Alpha PCI support. Most of the code
* moved to drivers/pci/pci.c.
*
* Dec 7, 1996 : Added support for direct configuration access of boards
* with Intel compatible access schemes (tsbogend@alpha.franken.de)
*
* Feb 3, 1997 : Set internal functions to static, save/restore flags
* avoid dead locks reading broken PCI BIOS, werner@suse.de
*
* Apr 26, 1997 : Fixed case when there is BIOS32, but not PCI BIOS
* (mj@atrey.karlin.mff.cuni.cz)
*
* May 7, 1997 : Added some missing cli()'s. [mj]
*
* Jun 20, 1997 : Corrected problems in "conf1" type accesses.
* (paubert@iram.es)
*
* Aug 2, 1997 : Split to PCI BIOS handling and direct PCI access parts
* and cleaned it up... Martin Mares <mj@atrey.karlin.mff.cuni.cz>
*
* Feb 6, 1998 : No longer using BIOS to find devices and device classes. [mj]
*
* May 1, 1998 : Support for peer host bridges. [mj]
*
* Jun 19, 1998 : Changed to use spinlocks, so that PCI configuration space
* can be accessed from interrupts even on SMP systems. [mj]
*
* August 1998 : Better support for peer host bridges and more paranoid
* checks for direct hardware access. Ugh, this file starts to look as
* a large gallery of common hardware bug workarounds (watch the comments)
* -- the PCI specs themselves are sane, but most implementors should be
* hit hard with \hammer scaled \magstep5. [mj]
*
* Jan 23, 1999 : More improvements to peer host bridge logic. i450NX fixup. [mj]
*
* Feb 8, 1999 : Added UM8886BF I/O address fixup. [mj]
*
* August 1999 : New resource management and configuration access stuff. [mj]
*
* Sep 19, 1999 : Use PCI IRQ routing tables for detection of peer host bridges.
* Based on ideas by Chris Frantz and David Hinds. [mj]
*
* Sep 28, 1999 : Handle unreported/unassigned IRQs. Thanks to Shuu Yamaguchi
* for a lot of patience during testing. [mj]
*
* Oct 8, 1999 : Split to pci-i386.c, pci-pc.c and pci-visws.c. [mj]
*/
#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-i386.h"
void
98 pcibios_update_resource(struct pci_dev *dev, struct resource *root,
struct resource *res, int resource)
{
u32 new, check;
int reg;
new = res->start | (res->flags & PCI_REGION_FLAG_MASK);
105 if (resource < 6) {
reg = PCI_BASE_ADDRESS_0 + 4*resource;
107 } else if (resource == PCI_ROM_RESOURCE) {
res->flags |= PCI_ROM_ADDRESS_ENABLE;
new |= PCI_ROM_ADDRESS_ENABLE;
reg = dev->rom_base_reg;
111 } else {
/* Somebody might have asked allocation of a non-standard resource */
113 return;
}
pci_write_config_dword(dev, reg, new);
pci_read_config_dword(dev, reg, &check);
118 if ((new ^ check) & ((new & PCI_BASE_ADDRESS_SPACE_IO) ? PCI_BASE_ADDRESS_IO_MASK : PCI_BASE_ADDRESS_MEM_MASK)) {
printk(KERN_ERR "PCI: Error while updating region "
"%s/%d (%08x != %08x)\n", dev->slot_name, resource,
new, check);
}
}
/*
* 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
139 pcibios_align_resource(void *data, struct resource *res, unsigned long size)
{
141 if (res->flags & IORESOURCE_IO) {
unsigned long start = res->start;
144 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.
*/
185 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 */
194 for (ln=bus_list->next; ln != bus_list; ln=ln->next) {
bus = pci_bus_b(ln);
196 if ((dev = bus->self)) {
197 for (idx = PCI_BRIDGE_RESOURCES; idx < PCI_NUM_RESOURCES; idx++) {
r = &dev->resource[idx];
199 if (!r->start)
200 continue;
pr = pci_find_parent_resource(dev, r);
202 if (!pr || request_resource(pr, r) < 0)
printk(KERN_ERR "PCI: Cannot allocate resource region %d of bridge %s\n", idx, dev->slot_name);
}
}
pcibios_allocate_bus_resources(&bus->children);
}
}
210 static void __init pcibios_allocate_resources(int pass)
{
struct pci_dev *dev;
int idx, disabled;
u16 command;
struct resource *r, *pr;
217 pci_for_each_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, dev->slot_name);
/* 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 & PCI_ROM_ADDRESS_ENABLE) {
/* Turn the ROM off, leave the resource region, but keep it unregistered. */
u32 reg;
DBG("PCI: Switching off ROM of %s\n", dev->slot_name);
r->flags &= ~PCI_ROM_ADDRESS_ENABLE;
pci_read_config_dword(dev, dev->rom_base_reg, ®);
pci_write_config_dword(dev, dev->rom_base_reg, reg & ~PCI_ROM_ADDRESS_ENABLE);
}
}
}
}
255 static void __init pcibios_assign_resources(void)
{
struct pci_dev *dev;
int idx;
struct resource *r;
261 pci_for_each_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);
}
}
}
297 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();
}
306 int pcibios_enable_resources(struct pci_dev *dev)
{
u16 cmd, old_cmd;
int idx;
struct resource *r;
pci_read_config_word(dev, PCI_COMMAND, &cmd);
old_cmd = cmd;
314 for(idx=0; idx<6; idx++) {
r = &dev->resource[idx];
316 if (!r->start && r->end) {
printk(KERN_ERR "PCI: Device %s not available because of resource collisions\n", dev->slot_name);
318 return -EINVAL;
}
320 if (r->flags & IORESOURCE_IO)
cmd |= PCI_COMMAND_IO;
322 if (r->flags & IORESOURCE_MEM)
cmd |= PCI_COMMAND_MEMORY;
}
325 if (dev->resource[PCI_ROM_RESOURCE].start)
cmd |= PCI_COMMAND_MEMORY;
327 if (cmd != old_cmd) {
printk("PCI: Enabling device %s (%04x -> %04x)\n", dev->slot_name, old_cmd, cmd);
pci_write_config_word(dev, PCI_COMMAND, cmd);
}
331 return 0;
}
/*
* 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;
340 void pcibios_set_master(struct pci_dev *dev)
{
u8 lat;
pci_read_config_byte(dev, PCI_LATENCY_TIMER, &lat);
344 if (lat < 16)
lat = (64 <= pcibios_max_latency) ? 64 : pcibios_max_latency;
346 else if (lat > pcibios_max_latency)
lat = pcibios_max_latency;
348 else
349 return;
printk("PCI: Setting latency timer of device %s to %d\n", dev->slot_name, lat);
pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat);
}