android_kernel_xiaomi_sm8350/arch/i386/pci/mmconfig.c
Linus Torvalds de8e7c1243 Revert "[PATCH] i386: Add MMCFG resources to i386 too"
This reverts commit de09bddb9d.  It tried
to reserve the MMCONFIG mmio memory ranges, but since the MMCONFIG
information is broken and often bogus (which is why we don't dare use it
most of the time _anyway_), it does more harm than good.

Cc: Jeff Chua <jeff.chua.linux@gmail.com>
Cc: Adrian Bunk <bunk@stusta.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-11-08 10:09:28 -08:00

221 lines
5.4 KiB
C

/*
* Copyright (C) 2004 Matthew Wilcox <matthew@wil.cx>
* Copyright (C) 2004 Intel Corp.
*
* This code is released under the GNU General Public License version 2.
*/
/*
* mmconfig.c - Low-level direct PCI config space access via MMCONFIG
*/
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/acpi.h>
#include <asm/e820.h>
#include "pci.h"
/* aperture is up to 256MB but BIOS may reserve less */
#define MMCONFIG_APER_MIN (2 * 1024*1024)
#define MMCONFIG_APER_MAX (256 * 1024*1024)
/* Assume systems with more busses have correct MCFG */
#define MAX_CHECK_BUS 16
#define mmcfg_virt_addr ((void __iomem *) fix_to_virt(FIX_PCIE_MCFG))
/* The base address of the last MMCONFIG device accessed */
static u32 mmcfg_last_accessed_device;
static DECLARE_BITMAP(fallback_slots, MAX_CHECK_BUS*32);
/*
* Functions for accessing PCI configuration space with MMCONFIG accesses
*/
static u32 get_base_addr(unsigned int seg, int bus, unsigned devfn)
{
int cfg_num = -1;
struct acpi_table_mcfg_config *cfg;
if (seg == 0 && bus < MAX_CHECK_BUS &&
test_bit(PCI_SLOT(devfn) + 32*bus, fallback_slots))
return 0;
while (1) {
++cfg_num;
if (cfg_num >= pci_mmcfg_config_num) {
break;
}
cfg = &pci_mmcfg_config[cfg_num];
if (cfg->pci_segment_group_number != seg)
continue;
if ((cfg->start_bus_number <= bus) &&
(cfg->end_bus_number >= bus))
return cfg->base_address;
}
/* Handle more broken MCFG tables on Asus etc.
They only contain a single entry for bus 0-0. Assume
this applies to all busses. */
cfg = &pci_mmcfg_config[0];
if (pci_mmcfg_config_num == 1 &&
cfg->pci_segment_group_number == 0 &&
(cfg->start_bus_number | cfg->end_bus_number) == 0)
return cfg->base_address;
/* Fall back to type 0 */
return 0;
}
/*
* This is always called under pci_config_lock
*/
static void pci_exp_set_dev_base(unsigned int base, int bus, int devfn)
{
u32 dev_base = base | (bus << 20) | (devfn << 12);
if (dev_base != mmcfg_last_accessed_device) {
mmcfg_last_accessed_device = dev_base;
set_fixmap_nocache(FIX_PCIE_MCFG, dev_base);
}
}
static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
unsigned int devfn, int reg, int len, u32 *value)
{
unsigned long flags;
u32 base;
if ((bus > 255) || (devfn > 255) || (reg > 4095)) {
*value = -1;
return -EINVAL;
}
base = get_base_addr(seg, bus, devfn);
if (!base)
return pci_conf1_read(seg,bus,devfn,reg,len,value);
spin_lock_irqsave(&pci_config_lock, flags);
pci_exp_set_dev_base(base, bus, devfn);
switch (len) {
case 1:
*value = readb(mmcfg_virt_addr + reg);
break;
case 2:
*value = readw(mmcfg_virt_addr + reg);
break;
case 4:
*value = readl(mmcfg_virt_addr + reg);
break;
}
spin_unlock_irqrestore(&pci_config_lock, flags);
return 0;
}
static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
unsigned int devfn, int reg, int len, u32 value)
{
unsigned long flags;
u32 base;
if ((bus > 255) || (devfn > 255) || (reg > 4095))
return -EINVAL;
base = get_base_addr(seg, bus, devfn);
if (!base)
return pci_conf1_write(seg,bus,devfn,reg,len,value);
spin_lock_irqsave(&pci_config_lock, flags);
pci_exp_set_dev_base(base, bus, devfn);
switch (len) {
case 1:
writeb(value, mmcfg_virt_addr + reg);
break;
case 2:
writew(value, mmcfg_virt_addr + reg);
break;
case 4:
writel(value, mmcfg_virt_addr + reg);
break;
}
spin_unlock_irqrestore(&pci_config_lock, flags);
return 0;
}
static struct pci_raw_ops pci_mmcfg = {
.read = pci_mmcfg_read,
.write = pci_mmcfg_write,
};
/* K8 systems have some devices (typically in the builtin northbridge)
that are only accessible using type1
Normally this can be expressed in the MCFG by not listing them
and assigning suitable _SEGs, but this isn't implemented in some BIOS.
Instead try to discover all devices on bus 0 that are unreachable using MM
and fallback for them. */
static __init void unreachable_devices(void)
{
int i, k;
unsigned long flags;
for (k = 0; k < MAX_CHECK_BUS; k++) {
for (i = 0; i < 32; i++) {
u32 val1;
u32 addr;
pci_conf1_read(0, k, PCI_DEVFN(i, 0), 0, 4, &val1);
if (val1 == 0xffffffff)
continue;
/* Locking probably not needed, but safer */
spin_lock_irqsave(&pci_config_lock, flags);
addr = get_base_addr(0, k, PCI_DEVFN(i, 0));
if (addr != 0)
pci_exp_set_dev_base(addr, k, PCI_DEVFN(i, 0));
if (addr == 0 ||
readl((u32 __iomem *)mmcfg_virt_addr) != val1) {
set_bit(i + 32*k, fallback_slots);
printk(KERN_NOTICE
"PCI: No mmconfig possible on %x:%x\n", k, i);
}
spin_unlock_irqrestore(&pci_config_lock, flags);
}
}
}
void __init pci_mmcfg_init(int type)
{
if ((pci_probe & PCI_PROBE_MMCONF) == 0)
return;
acpi_table_parse(ACPI_MCFG, acpi_parse_mcfg);
if ((pci_mmcfg_config_num == 0) ||
(pci_mmcfg_config == NULL) ||
(pci_mmcfg_config[0].base_address == 0))
return;
/* Only do this check when type 1 works. If it doesn't work
assume we run on a Mac and always use MCFG */
if (type == 1 && !e820_all_mapped(pci_mmcfg_config[0].base_address,
pci_mmcfg_config[0].base_address + MMCONFIG_APER_MIN,
E820_RESERVED)) {
printk(KERN_ERR "PCI: BIOS Bug: MCFG area at %x is not E820-reserved\n",
pci_mmcfg_config[0].base_address);
printk(KERN_ERR "PCI: Not using MMCONFIG.\n");
return;
}
printk(KERN_INFO "PCI: Using MMCONFIG\n");
raw_pci_ops = &pci_mmcfg;
pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF;
unreachable_devices();
}