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#include <device/smbus_def.h>
#define SMBHSTSTAT 0x0
#define SMBHSTCTL 0x2
#define SMBHSTCMD 0x3
#define SMBXMITADD 0x4
#define SMBHSTDAT0 0x5
#define SMBHSTDAT1 0x6
#define SMBBLKDAT 0x7
#define SMBTRNSADD 0x9
#define SMBSLVDATA 0xa
#define SMLINK_PIN_CTL 0xe
#define SMBUS_PIN_CTL 0xf
#define SMBUS_TIMEOUT (100*1000*10)
static void smbus_delay(void)
{
outb(0x80, 0x80);
}
static int smbus_wait_until_ready(unsigned smbus_io_base)
{
unsigned loops = SMBUS_TIMEOUT;
unsigned char byte;
do {
smbus_delay();
if (--loops == 0)
break;
byte = inb(smbus_io_base + SMBHSTSTAT);
} while(byte & 1);
return loops?0:-1;
}
static int smbus_wait_until_done(unsigned smbus_io_base)
{
unsigned loops = SMBUS_TIMEOUT;
unsigned char byte;
do {
smbus_delay();
if (--loops == 0)
break;
byte = inb(smbus_io_base + SMBHSTSTAT);
} while((byte & 1) || (byte & ~((1<<6)|(1<<0))) == 0);
return loops?0:-1;
}
static int smbus_wait_until_blk_done(unsigned smbus_io_base)
{
unsigned loops = SMBUS_TIMEOUT;
unsigned char byte;
do {
smbus_delay();
if (--loops == 0)
break;
byte = inb(smbus_io_base + SMBHSTSTAT);
} while((byte&(1<<7)) == 0);
return loops?0:-1;
}
static int do_smbus_read_byte(unsigned smbus_io_base, unsigned device, unsigned address)
{
unsigned char global_status_register;
unsigned char byte;
if (smbus_wait_until_ready(smbus_io_base) < 0) {
return SMBUS_WAIT_UNTIL_READY_TIMEOUT;
}
/* setup transaction */
/* disable interrupts */
outb(inb(smbus_io_base + SMBHSTCTL) & (~1), smbus_io_base + SMBHSTCTL);
/* set the device I'm talking too */
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 the command */
outb((inb(smbus_io_base + SMBHSTCTL) | 0x40), smbus_io_base + SMBHSTCTL);
/* poll for transaction completion */
if (smbus_wait_until_done(smbus_io_base) < 0) {
return SMBUS_WAIT_UNTIL_DONE_TIMEOUT;
}
global_status_register = inb(smbus_io_base + SMBHSTSTAT);
/* Ignore the In Use Status... */
global_status_register &= ~(3 << 5);
/* read results of transaction */
byte = inb(smbus_io_base + SMBHSTDAT0);
if (global_status_register != (1 << 1)) {
return SMBUS_ERROR;
}
return byte;
}
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