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#include <device/pci_ids.h>
#include "i82801cx.h"
static void enable_smbus(void)
{
device_t dev = PCI_DEV(0x0, 0x1f, 0x3);
printk(BIOS_DEBUG, "SMBus controller enabled\n");
/* set smbus iobase */
pci_write_config32(dev, SMB_BASE, SMBUS_IO_BASE | PCI_BASE_ADDRESS_SPACE_IO);
/* Set smbus enable */
pci_write_config8(dev, HOSTC, HST_EN);
/* Set smbus iospace enable */
pci_write_config16(dev, PCI_COMMAND, PCI_COMMAND_IO);
/* Disable interrupt generation */
outb(0, SMBUS_IO_BASE + SMBHSTCTL);
/* clear any lingering errors, so the transaction will run */
outb(inb(SMBUS_IO_BASE + SMBHSTSTAT), SMBUS_IO_BASE + SMBHSTSTAT);
}
static inline void smbus_delay(void)
{
outb(0x80, 0x80);
}
// See http://www.coreboot.org/pipermail/linuxbios/2004-September/009077.html
// for a description of this function.
static int smbus_wait_until_active(void)
{
unsigned long loops;
loops = SMBUS_TIMEOUT;
do {
unsigned char val;
smbus_delay();
val = inb(SMBUS_IO_BASE + SMBHSTSTAT);
if ((val & 1)) {
break;
}
} while (--loops);
return loops ? 0 : -4;
}
static int smbus_wait_until_ready(void)
{
unsigned long loops;
loops = SMBUS_TIMEOUT;
do {
unsigned char val;
smbus_delay();
val = inb(SMBUS_IO_BASE + SMBHSTSTAT);
// !HOST_BUSY?
if ((val & 1) == 0) {
break;
}
if(loops == (SMBUS_TIMEOUT / 2)) {
// Clear status flags
outb(inb(SMBUS_IO_BASE + SMBHSTSTAT),
SMBUS_IO_BASE + SMBHSTSTAT);
}
} while(--loops);
return loops?0:-2;
}
static int smbus_wait_until_done(void)
{
unsigned long loops;
loops = SMBUS_TIMEOUT;
do {
unsigned char val;
smbus_delay();
val = inb(SMBUS_IO_BASE + SMBHSTSTAT);
// !HOST_BUSY?
if ( (val & 1) == 0) {
break;
}
// BYTE_DONE or SUCCESS or error?
if ((val & ~((1<<6)|(1<<0)) ) != 0 ) {
break;
}
} while(--loops);
return loops?0:-3;
}
static int smbus_read_byte(unsigned device, unsigned address)
{
unsigned char global_control_register;
unsigned char global_status_register;
unsigned char byte;
if (smbus_wait_until_ready() < 0) {
return -2;
}
/* setup transaction */
/* disable interrupts */
outb(inb(SMBUS_IO_BASE + SMBHSTCTL) & 0xfe, SMBUS_IO_BASE + SMBHSTCTL);
/* set to read from the specified device */
outb(((device & 0x7f) << 1) | 1, SMBUS_IO_BASE + SMBXMITADD);
/* set the command/address... */
outb(address & 0xFF, SMBUS_IO_BASE + SMBHSTCMD);
/* set up for a byte data read */
outb((inb(SMBUS_IO_BASE + SMBHSTCTL) & 0xe3) | (0x2<<2), SMBUS_IO_BASE + SMBHSTCTL);
/* clear any lingering errors, so the transaction will run */
outb(inb(SMBUS_IO_BASE + SMBHSTSTAT), SMBUS_IO_BASE + SMBHSTSTAT);
/* clear the data byte...*/
outb(0, SMBUS_IO_BASE + SMBHSTDAT0);
/* start a byte read, with interrupts disabled */
outb((inb(SMBUS_IO_BASE + SMBHSTCTL) | 0x40), SMBUS_IO_BASE + SMBHSTCTL);
/* poll for it to start */
if (smbus_wait_until_active() < 0) {
return -4;
}
/* poll for transaction completion */
if (smbus_wait_until_done() < 0) {
return -3;
}
global_status_register = inb(SMBUS_IO_BASE + SMBHSTSTAT) & ~(1<<6); /* Ignore the In Use Status... */
/* read results of transaction */
byte = inb(SMBUS_IO_BASE + SMBHSTDAT0);
// SUCCESS?
if (global_status_register != 2) {
return -1;
}
return byte;
}
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