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/*
* This file is part of the LinuxBIOS project.
*
* Copyright (C) 2007 Corey Osgood <corey_osgood@verizon.net>
* Copyright (C) 2007 Rudolf Marek <r.marek@assembler.cz>
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <device/pci_ids.h>
#include <spd.h>
#include <stdlib.h>
#include "vt8237r.h"
/**
* Print an error, should it occur. If no error, just exit.
*
* @param host_status The data returned on the host status register after
* a transaction is processed.
* @param loops The number of times a transaction was attempted.
*/
static void smbus_print_error(u8 host_status, int loops)
{
/* Check if there actually was an error. */
if ((host_status == 0x00 || host_status == 0x40 ||
host_status == 0x42) && (loops < SMBUS_TIMEOUT))
return;
if (loops >= SMBUS_TIMEOUT)
print_err("SMBus timeout\r\n");
if (host_status & (1 << 4))
print_err("Interrupt/SMI# was Failed Bus Transaction\r\n");
if (host_status & (1 << 3))
print_err("Bus error\r\n");
if (host_status & (1 << 2))
print_err("Device error\r\n");
if (host_status & (1 << 1))
print_debug("Interrupt/SMI# completed successfully\r\n");
if (host_status & (1 << 0))
print_err("Host busy\r\n");
}
/**
* Wait for the SMBus to become ready to process the next transaction.
*/
static void smbus_wait_until_ready(void)
{
int loops;
PRINT_DEBUG("Waiting until SMBus ready\r\n");
loops = 0;
/* Yes, this is a mess, but it's the easiest way to do it. */
while ((inb(SMBHSTSTAT) & 1) == 1 && loops < SMBUS_TIMEOUT)
++loops;
smbus_print_error(inb(SMBHSTSTAT), loops);
}
/**
* Reset and take ownership of the SMBus.
*/
static void smbus_reset(void)
{
outb(HOST_RESET, SMBHSTSTAT);
/* Datasheet says we have to read it to take ownership of SMBus. */
inb(SMBHSTSTAT);
PRINT_DEBUG("After reset status: ");
PRINT_DEBUG_HEX16(inb(SMBHSTSTAT));
PRINT_DEBUG("\r\n");
}
/**
* Read a byte from the SMBus.
*
* @param dimm The address location of the DIMM on the SMBus.
* @param offset The offset the data is located at.
*/
u8 smbus_read_byte(u8 dimm, u8 offset)
{
u8 val;
PRINT_DEBUG("DIMM ");
PRINT_DEBUG_HEX16(dimm);
PRINT_DEBUG(" OFFSET ");
PRINT_DEBUG_HEX16(offset);
PRINT_DEBUG("\r\n");
smbus_reset();
/* Clear host data port. */
outb(0x00, SMBHSTDAT0);
SMBUS_DELAY();
smbus_wait_until_ready();
/* Actual addr to reg format. */
dimm = (dimm << 1);
dimm |= 1;
outb(dimm, SMBXMITADD);
outb(offset, SMBHSTCMD);
/* Start transaction, byte data read. */
outb(0x48, SMBHSTCTL);
SMBUS_DELAY();
smbus_wait_until_ready();
val = inb(SMBHSTDAT0);
PRINT_DEBUG("Read: ");
PRINT_DEBUG_HEX16(val);
PRINT_DEBUG("\r\n");
/* Probably don't have to do this, but it can't hurt. */
smbus_reset();
return val;
}
/**
* Enable the smbus on vt8237r-based systems
*/
void enable_smbus(void)
{
device_t dev;
/* Power management controller */
dev = pci_locate_device(PCI_ID(PCI_VENDOR_ID_VIA,
PCI_DEVICE_ID_VIA_VT8237R_LPC), 0);
if (dev == PCI_DEV_INVALID)
die("Power management controller not found\r\n");
/* 7 = SMBus Clock from RTC 32.768KHz
* 5 = Internal PLL reset from susp
*/
pci_write_config8(dev, VT8237R_POWER_WELL, 0xa0);
/* Enable SMBus. */
pci_write_config16(dev, VT8237R_SMBUS_IO_BASE_REG,
VT8237R_SMBUS_IO_BASE | 0x1);
/* SMBus Host Configuration, enable. */
pci_write_config8(dev, VT8237R_SMBUS_HOST_CONF, 0x01);
/* Make it work for I/O. */
pci_write_config16(dev, PCI_COMMAND, PCI_COMMAND_IO);
smbus_reset();
/* Reset the internal pointer. */
inb(SMBHSTCTL);
}
/**
* A fixup for some systems that need time for the SMBus to "warm up". This is
* needed on some VT823x based systems, where the SMBus spurts out bad data for
* a short time after power on. This has been seen on the VIA Epia series and
* Jetway J7F2-series. It reads the ID byte from SMBus, looking for
* known-good data from a slot/address. Exits on either good data or a timeout.
*
* TODO: This should probably go into some global file, but one would need to
* be created just for it. If some other chip needs/wants it, we can
* worry about it then.
*
* @param ctrl The memory controller and SMBus addresses.
*/
void smbus_fixup(const struct mem_controller *ctrl)
{
int i, ram_slots, current_slot = 0;
u8 result = 0;
ram_slots = ARRAY_SIZE(ctrl->channel0);
if (!ram_slots) {
print_err("smbus_fixup() thinks there are no RAM slots!\r\n");
return;
}
PRINT_DEBUG("Waiting for SMBus to warm up");
/*
* Bad SPD data should be either 0 or 0xff, but YMMV. So we look for
* the ID bytes of SDRAM, DDR, DDR2, and DDR3 (and anything in between).
* VT8237R has only been seen on DDR and DDR2 based systems, so far.
*/
for (i = 0; (i < SMBUS_TIMEOUT && ((result < SPD_MEMORY_TYPE_SDRAM) ||
(result > SPD_MEMORY_TYPE_SDRAM_DDR3))); i++) {
if (current_slot > ram_slots)
current_slot = 0;
result = smbus_read_byte(ctrl->channel0[current_slot],
SPD_MEMORY_TYPE);
current_slot++;
PRINT_DEBUG(".");
}
if (i >= SMBUS_TIMEOUT)
print_err("SMBus timed out while warming up\r\n");
else
PRINT_DEBUG("Done\r\n");
}
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