GNUBoot
/
coreboot-kgpe-d16
2
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Intel e7505: refactor only 

Drop comments (from e7501 era) which no longer seem to apply with
e7505. Write the semi-constant D0:F0 table as code. Some register
settings seem to be in different order compared with vendor BIOS,
and will be handled by follow-up patches.

Split RCOMP register copy function in two parts.
Drop some uses of inline and local_mdelay().

Change-Id: I8739d3b2bbad5861118e8b16ccea1dd86991204f
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/896
Tested-by: build bot (Jenkins)
Reviewed-by: Peter Stuge <peter@stuge.se>
This commit is contained in:
Kyösti Mälkki 2012-04-18 19:47:56 +03:00 committed by Peter Stuge
parent d1edb177e8
commit 77e4f7ddda
1 changed files with 97 additions and 381 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

478
src/northbridge/intel/e7505/raminit.c
View File

@ -100,229 +100,38 @@ static const uint8_t dual_channel_parameters[] = {
SPD_NUM_BANKS_PER_SDRAM
};
/*
* Table: constant_register_values
/* Comments here are remains of e7501 or even 855PM.
* They might be partially (in)correct for e7505.
*/
static const long constant_register_values[] = {
/* SVID - Subsystem Vendor Identification Register
* 0x2c - 0x2d
* [15:00] Subsytem Vendor ID (Indicates system board vendor)
*/
/* SID - Subsystem Identification Register
* 0x2e - 0x2f
* [15:00] Subsystem ID
*/
// Not everyone wants to be Super Micro Computer, Inc.
// The mainboard should set this if desired.
// 0x2c, 0, (0x15d9 << 0) | (0x3580 << 16),
/* Undocumented
* (DRAM Read Timing Control, if similar to 855PM?)
* 0x80 - 0x81
/* (DRAM Read Timing Control, if similar to 855PM?)
* 0x80 - 0x81 documented differently for e7505
* This register has something to do with CAS latencies,
* possibily this is the real chipset control.
* At 0x00 CAS latency 1.5 works.
* At 0x06 CAS latency 2.5 works.
* At 0x01 CAS latency 2.0 works.
*/
/* This is still undocumented in e7501, but with different values
*
* This is still undocumented in e7501, but with different values
* CAS 2.0 values taken from Intel BIOS settings, others are a guess
* and may be terribly wrong. Old values preserved as comments until I
* figure this out for sure.
* e7501 docs claim that CAS1.5 is unsupported, so it may or may not
* work at all.
* Steven James 02/06/2003
*/
/* NOTE: values now configured in configure_e7501_cas_latency() based
*
* NOTE: values now configured in configure_e7501_cas_latency() based
* on SPD info and total number of DIMMs (per Intel)
*/
/* FDHC - Fixed DRAM Hole Control
* 0x58
/* FDHC - Fixed DRAM Hole Control ???
* 0x58 undocumented for e7505, memory hole in southbridge configuration?
* [7:7] Hole_Enable
* 0 == No memory Hole
* 1 == Memory Hole from 15MB to 16MB
* [6:0] Reserved
*
* PAM - Programmable Attribute Map
* 0x59 [1:0] Reserved
* 0x59 [5:4] 0xF0000 - 0xFFFFF
* 0x5A [1:0] 0xC0000 - 0xC3FFF
* 0x5A [5:4] 0xC4000 - 0xC7FFF
* 0x5B [1:0] 0xC8000 - 0xCBFFF
* 0x5B [5:4] 0xCC000 - 0xCFFFF
* 0x5C [1:0] 0xD0000 - 0xD3FFF
* 0x5C [5:4] 0xD4000 - 0xD7FFF
* 0x5D [1:0] 0xD8000 - 0xDBFFF
* 0x5D [5:4] 0xDC000 - 0xDFFFF
* 0x5E [1:0] 0xE0000 - 0xE3FFF
* 0x5E [5:4] 0xE4000 - 0xE7FFF
* 0x5F [1:0] 0xE8000 - 0xEBFFF
* 0x5F [5:4] 0xEC000 - 0xEFFFF
* 00 == DRAM Disabled (All Access go to memory mapped I/O space)
* 01 == Read Only (Reads to DRAM, Writes to memory mapped I/O space)
* 10 == Write Only (Writes to DRAM, Reads to memory mapped I/O space)
* 11 == Normal (All Access go to DRAM)
*/
// Map all legacy ranges to DRAM
0x58, 0xcccccf7f, (0x00 << 0) | (0x30 << 8) | (0x33 << 16) | (0x33 << 24),
0x5C, 0xcccccccc, (0x33 << 0) | (0x33 << 8) | (0x33 << 16) | (0x33 << 24),
/* DRB - DRAM Row Boundary Registers
* 0x60 - 0x6F
* An array of 8 byte registers, which hold the ending
* memory address assigned to each pair of DIMMS, in 64MB
* granularity.
*/
// Conservatively say each row has 64MB of ram, we will fix this up later
// NOTE: These defaults allow us to prime all of the DIMMs on the board
// without jumping through 36-bit adddressing hoops, even if the
// total memory is > 4 GB. Changing these values may break do_ram_command()!
0x60, 0x00000000, (0x01 << 0) | (0x02 << 8) | (0x03 << 16) | (0x04 << 24),
// 0x64, 0x00000000, (0x05 << 0) | (0x06 << 8) | (0x07 << 16) | (0x08 << 24),
0x64, 0x00000000, (0x04 << 0) | (0x04 << 8) | (0x04 << 16) | (0x04 << 24),
/* DRA - DRAM Row Attribute Register
* 0x70 Row 0,1
* 0x71 Row 2,3
* 0x72 Row 4,5
* 0x73 Row 6,7
* [7:7] Device width for Odd numbered rows
* 0 == 8 bits wide x8
* 1 == 4 bits wide x4
* [6:4] Row Attributes for Odd numbered rows
* 010 == 8KB (for dual-channel)
* 011 == 16KB (for dual-channel)
* 100 == 32KB (for dual-channel)
* 101 == 64KB (for dual-channel)
* Others == Reserved
* [3:3] Device width for Even numbered rows
* 0 == 8 bits wide x8
* 1 == 4 bits wide x4
* [2:0] Row Attributes for Even numbered rows
* 010 == 8KB (for dual-channel)
* 011 == 16KB (for dual-channel)
* 100 == 32KB (for dual-channel)
* 101 == 64KB (This page size appears broken)
* Others == Reserved
*/
// NOTE: overridden by configure_e7501_row_attributes(), later
0x70, 0x00000000, 0,
/* DRT - DRAM Timing Register
* 0x78
* [31:30] Reserved
* [29:29] Back to Back Write-Read Turn Around
* 0 == 3 clocks between WR-RD commands
* 1 == 2 clocks between WR-RD commands
* [28:28] Back to Back Read-Write Turn Around
* 0 == 5 clocks between RD-WR commands
* 1 == 4 clocks between RD-WR commands
* [27:27] Back to Back Read Turn Around
* 0 == 4 clocks between RD commands
* 1 == 3 clocks between RD commands
* [26:24] Read Delay (tRD)
* 000 == 7 clocks
* 001 == 6 clocks
* 010 == 5 clocks
* Others == Reserved
* [23:19] Reserved
* [18:16] DRAM idle timer
* 000 == infinite
* 011 == 16 dram clocks
* 001 == 0 clocks
* [15:11] Reserved
* [10:09] Active to Precharge (tRAS)
* 00 == 7 clocks
* 01 == 6 clocks
* 10 == 5 clocks
* 11 == Reserved
* [08:06] Reserved
* [05:04] Cas Latency (tCL)
* 00 == 2.5 Clocks
* 01 == 2.0 Clocks
* 10 == Reserved (was 1.5 Clocks for E7500)
* 11 == Reserved
* [03:03] Write Ras# to Cas# Delay (tRCD)
* 0 == 3 DRAM Clocks
* 1 == 2 DRAM Clocks
* [02:01] Read RAS# to CAS# Delay (tRCD)
* 00 == reserved
* 01 == reserved
* 10 == 3 DRAM Clocks
* 11 == 2 DRAM Clocks
* [00:00] DRAM RAS# to Precharge (tRP)
* 0 == 3 DRAM Clocks
* 1 == 2 DRAM Clocks
*/
// Some earlier settings:
/* Most aggressive settings possible */
// 0x78, 0xc0fff8c4, (1<<29)|(1<<28)|(1<<27)|(2<<24)|(2<<9)|CAS_LATENCY|(1<<3)|(1<<1)|(1<<0),
// 0x78, 0xc0f8f8c0, (1<<29)|(1<<28)|(1<<27)|(1<<24)|(1<<16)|(2<<9)|CAS_LATENCY|(1<<3)|(3<<1)|(1<<0),
// 0x78, 0xc0f8f9c0, (1<<29)|(1<<28)|(1<<27)|(1<<24)|(1<<16)|(2<<9)|CAS_LATENCY|(1<<3)|(3<<1)|(1<<0),
// The only things we need to set here are DRAM idle timer, Back-to-Back Read Turnaround, and
// Back-to-Back Write-Read Turnaround. All others are configured based on SPD.
// 0x78, 0xD7F8FFFF, (1 << 29) | (1 << 27) | (1 << 16),
0x78, 0xC7F8FFFF, (0x03<<16)|(0x28<<24),
/* FIXME why was I attempting to set a reserved bit? */
/* 0x0100040f */
/* DRC - DRAM Contoller Mode Register
* 0x7c
* [31:30] Reserved
* [29:29] Initialization Complete
* 0 == Not Complete
* 1 == Complete
* [28:23] Reserved
* [22:22] Channels
* 0 == Single channel
* 1 == Dual Channel
* [21:20] DRAM Data Integrity Mode
* 00 == Disabled, no ECC
* 01 == Reserved
* 10 == Error checking, using chip-kill, with correction
* 11 == Reserved
* [19:18] DRB Granularity (Read-Only)
* 00 == 32 MB quantities (single channel mode)
* 01 == 64 MB quantities (dual-channel mode)
* 10 == Reserved
* 11 == Reserved
* [17:17] (Intel Undocumented) should always be set to 1 (SJM: comment inconsistent with current setting, below)
* [16:16] Command Per Clock - Address/Control Assertion Rule (CPC)
* 0 == 2n Rule
* 1 == 1n rule
* [15:11] Reserved
* [10:08] Refresh mode select
* 000 == Refresh disabled
* 001 == Refresh interval 15.6 usec
* 010 == Refresh interval 7.8 usec
* 011 == Refresh interval 64 usec
* 111 == Refresh every 64 clocks (fast refresh)
* [07:07] Reserved
* [06:04] Mode Select (SMS)
* 000 == Reserved (was Self Refresh Mode in E7500)
* 001 == NOP Command
* 010 == All Banks Precharge
* 011 == Mode Register Set
* 100 == Extended Mode Register Set
* 101 == Reserved
* 110 == CBR Refresh
* 111 == Normal Operation
* [03:00] Reserved
*/
// .long 0x7c, 0xffcefcff, (1<<22)|(2 << 20)|(1 << 16)| (0 << 8),
// .long 0x7c, 0xff8cfcff, (1<<22)|(2 << 20)|(1 << 17)|(1 << 16)| (0 << 8),
// .long 0x7c, 0xff80fcff, (1<<22)|(2 << 20)|(1 << 18)|(1 << 17)|(1 << 16)| (0 << 8),
// Default to dual-channel mode, ECC, 1-clock address/cmd hold
// NOTE: configure_e7501_dram_controller_mode() configures further
// 0x7c, 0xff8ef8ff, (1 << 22) | (2 << 20) | (1 << 16) | (0 << 8),
0x7c, 0xffcef8f7, 0x00210008,
/* Another Intel undocumented register
* 0x88 - 0x8B
* [31:31] Purpose unknown
@ -336,118 +145,8 @@ static const long constant_register_values[] = {
* 0 == Normal operation?
* 1 == Reset?
*/
// NOTE: Some factory BIOSs don't do this.
// Doesn't seem to matter either way.
0x88, 0xffffff00, 0x80,
/* CLOCK_DIS - CK/CK# Disable Register
* 0x8C
* [7:7] DDR Frequency
* 0 == 100 MHz (200 MHz data rate)
* 1 == 133 MHz (266 MHz data rate)
* [6:4] Reserved
* [3:3] CK3
* 0 == Enable
* 1 == Disable
* [2:2] CK2
* 0 == Enable
* 1 == Disable
* [1:1] CK1
* 0 == Enable
* 1 == Disable
* [0:0] CK0
* 0 == Enable
* 1 == Disable
*/
// NOTE: Disable all clocks initially; turn ones we need back on
// in enable_e7501_clocks()
0x8C, 0xfffffff0, 0xf,
/* TOLM - Top of Low Memory Register
* 0xC4 - 0xC5
* [15:11] Top of low memory (TOLM)
* The address below 4GB that should be treated as RAM,
* on a 128MB granularity.
* [10:00] Reserved
*/
/* REMAPBASE - Remap Base Address Regsiter
* 0xC6 - 0xC7
* [15:10] Reserved
* [09:00] Remap Base Address [35:26] 64M aligned
* Bits [25:0] are assumed to be 0.
*/
// NOTE: TOLM overridden by configure_e7501_ram_addresses()
0xc4, 0xfc0007ff, (0x2000 << 0) | (0x3ff << 16),
/* REMAPLIMIT - Remap Limit Address Register
* 0xC8 - 0xC9
* [15:10] Reserved
* [09:00] Remap Limit Address [35:26] 64M aligned
* When remaplimit < remapbase the remap window is disabled.
*/
0xc8, 0xfffffc00, 0,
/* DVNP - Device Not Present Register
* 0xE0 - 0xE1
* [15:05] Reserved
* [04:04] Device 4 Function 1 Present
* 0 == Present
* 1 == Absent
* [03:03] Device 3 Function 1 Present
* 0 == Present
* 1 == Absent
* [02:02] Device 2 Function 1 Present
* 0 == Present
* 1 == Absent
* [01:01] Reserved
* [00:00] Device 0 Function 1 Present
* 0 == Present
* 1 == Absent
*/
// Enable D0:D1, disable D2:F1, D3:F1, D4:F1
// 0xe0, 0xffffffe2, (1 << 4) | (1 << 3) | (1 << 2) | (0 << 0),
0xe0, 0xfffffffa, 0x0,
// Undocumented
0xd8, 0xffff9fff, 0x00000000,
// Undocumented - this is pure conjecture based on similarity to 855PM
/* MCHTST - MCH Test Register
* 0xF4 - 0xF7
* [31:31] Purpose unknown
* [30:30] Purpose unknown
* [29:23] Unknown - not used?
* [22:22] System Memory MMR Enable
* 0 == Disable: mem space and BAR at 0x14 are not accessible
* 1 == Enable: mem space and BAR at 0x14 are accessible
* [21:20] Purpose unknown
* [19:02] Unknown - not used?
* [01:01] D6EN (Device #6 enable)
* 0 == Disable
* 1 == Enable
* [00:00] Unknown - not used?
*/
// 0xf4, 0x3f8ffffd, 0x40300002,
#ifdef SUSPICIOUS_LOOKING_CODE
// SJM: Undocumented.
// This will access D2:F0:0x50, is this correct??
0x1050, 0xffffffcf, 0x00000030,
#endif
};
/* DDR RECOMP tables */
#if 0
// Slew table for 1x drive?
static const uint32_t 1x_slew_table[] = {
0x44332211, 0xc9776655, 0xffffffff, 0xffffffff,
0x22111111, 0x55444332, 0xfffca876, 0xffffffff,
};
#endif
/* DDR RECOMP tables */
// Slew table for 2x drive?
static const uint32_t slew_2x[] = {
0x00000000, 0x76543210, 0xffffeca8, 0xffffffff,
@ -466,21 +165,13 @@ Delay functions:
/* Estimate that SLOW_DOWN_IO takes about 1 us */
#define SLOW_DOWN_IO inb(0x80)
static inline void local_udelay(int i)
static void local_udelay(int i)
{
while (i--) {
SLOW_DOWN_IO;
}
}
static inline void local_mdelay(int i)
{
i *= 1000;
while (i--) {
SLOW_DOWN_IO;
}
}
/* delay for 200us */
#define DO_DELAY local_udelay(200)
#define EXTRA_DELAY DO_DELAY
@ -524,7 +215,7 @@ typedef enum {
* 1 == Enable
* [00:00] Unknown - not used?
*/
static inline void mchtest_control(mchtst_cc cmd)
static void mchtest_control(mchtst_cc cmd)
{
uint32_t dword = pci_read_config32(MCHDEV, MCHTST);
switch (cmd) {
@ -551,7 +242,7 @@ static inline void mchtest_control(mchtst_cc cmd)
/**
*
*/
static inline void d060_control(d060_cc cmd)
static void d060_control(d060_cc cmd)
{
mchtest_control(D060_ENABLE);
uint32_t dword = pci_read_config32(D060DEV, 0xf0);
@ -570,7 +261,7 @@ static inline void d060_control(d060_cc cmd)
/**
*
*/
static inline void rcomp_smr_control(rcomp_smr_cc cmd)
static void rcomp_smr_control(rcomp_smr_cc cmd)
{
uint32_t dword = read32(RCOMP_MMIO + SMRCTL);
switch (cmd) {
@ -995,6 +686,9 @@ static void do_ram_command(uint8_t command, uint16_t jedec_mode_bits)
dimm_start_64M_multiple = 0;
/* FIXME: Only address the number of rows present in the system?
* Seems like rows 4-7 overlap with 0-3.
*/
for (i = 0; i < (MAX_NUM_CHANNELS * MAX_DIMM_SOCKETS_PER_CHANNEL); ++i) {
uint8_t dimm_end_64M_multiple = pci_read_config8(MCHDEV, DRB_ROW_0 + i);
@ -1003,7 +697,7 @@ static void do_ram_command(uint8_t command, uint16_t jedec_mode_bits)
dimm_start_address &= 0x3ffffff;
dimm_start_address |= dimm_start_64M_multiple << 26;
read32(dimm_start_address);
// Set the start of the next DIMM
// Set the start of the next DIMM
dimm_start_64M_multiple = dimm_end_64M_multiple;
}
}
@ -1755,47 +1449,6 @@ static void RAM_RESET_DDR_PTR(void)
pci_write_config8(MCHDEV, 0x88, byte);
}
/**
* Set E7501 registers that are either independent of DIMM specifics, or
* establish default settings that will be overridden when we learn the
* specifics.
*
* This sets PCI configuration registers to known good values based on the
* table 'constant_register_values', which are a triple of configuration
* register offset, mask, and bits to set.
*/
static void ram_set_d0f0_regs(void)
{
int i;
int num_values = ARRAY_SIZE(constant_register_values);
ASSERT((num_values % 3) == 0); // Bad table?
for (i = 0; i < num_values; i += 3) {
uint32_t register_offset = constant_register_values[i];
uint32_t bits_to_mask = constant_register_values[i + 1];
uint32_t bits_to_set = constant_register_values[i + 2];
uint32_t register_value;
// It's theoretically possible to set values for something other than D0:F0,
// but it's not typically done here
ASSERT(!(register_offset & 0xFFFFFF00));
// bits_to_mask and bits_to_set should not reference the same bits
// Again, not strictly an error, but flagged as a potential bug
ASSERT((bits_to_mask & bits_to_set) == 0);
register_value =
pci_read_config32(MCHDEV, register_offset);
register_value &= bits_to_mask;
register_value |= bits_to_set;
pci_write_config32(MCHDEV, register_offset,
register_value);
}
}
/**
* Copy 64 bytes from one location to another.
*
@ -1822,20 +1475,13 @@ static void write_8dwords(const uint32_t *src_addr, uint32_t dst_addr)
* Comments below are conjecture based on apparent similarity between the
* E7501 and these two chips.
*/
static void ram_set_rcomp_regs(void)
static void rcomp_copy_registers(void)
{
uint32_t dword;
uint8_t strength_control, revision;
uint8_t strength_control;
RAM_DEBUG_MESSAGE("Setting RCOMP registers.\n");
/* Set the RCOMP MMIO base address */
mchtest_control(RCOMP_BAR_ENABLE);
pci_write_config32(MCHDEV, SMRBASE, RCOMP_MMIO);
/* Block RCOMP updates while we configure the registers */
rcomp_smr_control(RCOMP_HOLD);
/* Begin to write the RCOMP registers */
write8(RCOMP_MMIO + 0x2c, 0x0);
@ -1902,7 +1548,6 @@ static void ram_set_rcomp_regs(void)
write_8dwords(pull_updown_offset_table, RCOMP_MMIO + 0x1a0);
write16(RCOMP_MMIO + 0x4e, 0);
dword = read32(RCOMP_MMIO + 0x400);
dword &= 0x7f7fffff;
write32(RCOMP_MMIO + 0x400, dword);
@ -1910,18 +1555,27 @@ static void ram_set_rcomp_regs(void)
dword = read32(RCOMP_MMIO + 0x408);
dword &= 0x7f7fffff;
write32(RCOMP_MMIO + 0x408, dword);
}
static void ram_set_rcomp_regs(void)
{
/* Set the RCOMP MMIO base address */
mchtest_control(RCOMP_BAR_ENABLE);
pci_write_config32(MCHDEV, SMRBASE, RCOMP_MMIO);
/* Block RCOMP updates while we configure the registers */
rcomp_smr_control(RCOMP_HOLD);
rcomp_copy_registers();
d060_control(D060_CMD_0);
mchtest_control(MCHTST_CMD_0);
revision = pci_read_config8(MCHDEV, 0x08);
uint8_t revision = pci_read_config8(MCHDEV, 0x08);
if (revision >= 3) {
rcomp_smr_control(RCOMP_SMR_00);
rcomp_smr_control(RCOMP_SMR_01);
}
rcomp_smr_control(RCOMP_RELEASE);
/* Wait 40 usec */
SLOW_DOWN_IO;
@ -2084,11 +1738,73 @@ static void sdram_set_spd_registers(const struct mem_controller *ctrl)
*/
static void sdram_set_registers(const struct mem_controller *ctrl)
{
RAM_DEBUG_MESSAGE("Northbridge prior to SDRAM init:\n");
DUMPNORTH();
uint32_t dword;
uint16_t word;
uint8_t byte;
ram_set_rcomp_regs();
ram_set_d0f0_regs();
/* Enable 0:0.1, 0:2.1 */
word = pci_read_config16(MCHDEV, DVNP);
word &= ~0x05;
pci_write_config16(MCHDEV, DVNP, word);
/* Disable high-memory remap (power-on defaults, really) */
pci_write_config16(MCHDEV, REMAPBASE, 0x03ff);
pci_write_config16(MCHDEV, REMAPLIMIT, 0x0);
/* Disable legacy MMIO (0xC0000-0xEFFFF is DRAM) */
int i;
pci_write_config8(MCHDEV, PAM_0, 0x30);
for (i=1; i<=6; i++)
pci_write_config8(MCHDEV, PAM_0 + i, 0x33);
/* Conservatively say each row has 64MB of ram, we will fix this up later
* Initial TOLM 8 rows 64MB each (1<<3 * 1<<26) >> 16 = 1<<13
*
* FIXME: Hard-coded limit to first four rows to prevent overlap!
*/
pci_write_config32(MCHDEV, DRB_ROW_0, 0x04030201);
pci_write_config32(MCHDEV, DRB_ROW_4, 0x04040404);
//pci_write_config32(MCHDEV, DRB_ROW_4, 0x08070605);
pci_write_config16(MCHDEV, TOLM, (1<<13));
/* DIMM clocks off */
pci_write_config8(MCHDEV, CKDIS, 0xff);
/* reset row attributes */
pci_write_config32(MCHDEV, DRA, 0x0);
// The only things we need to set here are DRAM idle timer, Back-to-Back Read Turnaround, and
// Back-to-Back Write-Read Turnaround. All others are configured based on SPD.
dword = pci_read_config32(MCHDEV, DRT);
dword &= 0xC7F8FFFF;
dword |= (0x28<<24)|(0x03<<16);
pci_write_config32(MCHDEV, DRT, dword);
dword = pci_read_config32(MCHDEV, DRC);
dword &= 0xffcef8f7;
dword |= 0x00210008;
pci_write_config32(MCHDEV, DRC, dword);
/* Undocumented */
pci_write_config8(MCHDEV, 0x88, 0x80);
/* Undocumented. Set much later in vendor BIOS. */
byte = pci_read_config8(MCHDEV, 0xd9);
byte &= ~0x60;
pci_write_config8(MCHDEV, 0xd9, byte);
#ifdef SUSPICIOUS_LOOKING_CODE
/* This will access D2:F0:0x50, is this correct??
* Vendor BIOS reads Device ID before this is set.
* Undocumented in the p64h2 PCI-X bridge datasheet.
*/
byte = pci_read_config8(PCI_DEV(0,2,0), 0x50);
byte &= 0xcf;
byte |= 0x30
pci_write_config8(PCI_DEV(0,2,0), 0x50, byte);
#endif
uint8_t revision = pci_read_config8(MCHDEV, 0x08);
if (revision >= 3)