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#include <smbus.h>
#include <pci.h>
#include <arch/io.h>
#include "i82801cx.h"
#define PM_BUS 0
#define PM_DEVFN PCI_DEVFN(0x1f,3)
void smbus_enable(void)
{
/* iobase addr */
pcibios_write_config_dword(PM_BUS, PM_DEVFN, SMB_BASE,
SMBUS_IO_BASE | PCI_BASE_ADDRESS_SPACE_IO);
/* smbus enable */
pcibios_write_config_byte(PM_BUS, PM_DEVFN, HOSTC, HST_EN);
/* iospace enable */
pcibios_write_config_word(PM_BUS, PM_DEVFN, PCI_COMMAND, PCI_COMMAND_IO);
/* Disable interrupt generation */
outb(0, SMBUS_IO_BASE + SMBHSTCTL);
}
static void smbus_wait_until_ready(void)
{
// Loop while HOST_BUSY
while((inb(SMBUS_IO_BASE + SMBHSTSTAT) & 1) == 1) {
/* nop */
}
}
static void smbus_wait_until_done(void)
{
unsigned char byte;
// Loop while HOST_BUSY
do {
byte = inb(SMBUS_IO_BASE + SMBHSTSTAT);
}
while((byte &1) == 1);
// Wait for SUCCESS or error or BYTE_DONE
while( (byte & ~1) == 0) {
byte = inb(SMBUS_IO_BASE + SMBHSTSTAT);
}
}
int smbus_read_byte(unsigned device, unsigned address, unsigned char *result)
{
unsigned char host_status_register;
unsigned char byte;
smbus_wait_until_ready();
/* setup transaction */
/* disable interrupts */
outb(inb(SMBUS_IO_BASE + SMBHSTCTL) & (~1), SMBUS_IO_BASE + SMBHSTCTL);
/* set to read from the specified device */
outb(((device & 0x7f) << 1) | 1, SMBUS_IO_BASE + SMBHSTADD);
/* 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 the command */
outb((inb(SMBUS_IO_BASE + SMBHSTCTL) | 0x40), SMBUS_IO_BASE + SMBHSTCTL);
/* poll for transaction completion */
smbus_wait_until_done();
host_status_register = inb(SMBUS_IO_BASE + SMBHSTSTAT);
/* read results of transaction */
byte = inb(SMBUS_IO_BASE + SMBHSTDAT0);
*result = byte;
return host_status_register != 0x02; // return true if !SUCCESS
}
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