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#include <device/smbus_def.h>
#include "i82371eb.h"
#define SMBHST_STATUS 0x0
#define SMBHST_CTL 0x2
#define SMBHST_CMD 0x3
#define SMBHST_ADDR 0x4
#define SMBHST_DAT 0x5
#define SMBUS_TIMEOUT (100*1000*10)
#define SMBUS_STATUS_MASK 0x1e
#define SMBUS_ERROR_FLAG (1<<2)
int do_smbus_read_byte(unsigned smbus_io_base, unsigned device, unsigned address);
static inline void smbus_delay(void)
{
outb(0x80, 0x80);
outb(0x80, 0x80);
outb(0x80, 0x80);
outb(0x80, 0x80);
outb(0x80, 0x80);
outb(0x80, 0x80);
}
static int smbus_wait_until_ready(unsigned smbus_io_base)
{
unsigned long loops;
loops = SMBUS_TIMEOUT;
do {
unsigned char val;
smbus_delay();
val = inb(smbus_io_base + SMBHST_STATUS);
if ((val & 0x1) == 0) {
break;
}
#if 0
if(loops == (SMBUS_TIMEOUT / 2)) {
outw(inw(smbus_io_base + SMBHST_STATUS),
smbus_io_base + SMBHST_STATUS);
}
#endif
} while(--loops);
return loops?0:SMBUS_WAIT_UNTIL_READY_TIMEOUT;
}
static int smbus_wait_until_done(unsigned smbus_io_base)
{
unsigned long loops;
loops = SMBUS_TIMEOUT;
do {
unsigned short val;
smbus_delay();
val = inb(smbus_io_base + SMBHST_STATUS);
// Make sure the command is done
if ((val & 0x1) != 0) {
continue;
}
// Don't break out until one of the interrupt
// flags is set.
if (val & 0xfe) {
break;
}
} while(--loops);
return loops?0:SMBUS_WAIT_UNTIL_DONE_TIMEOUT;
}
int do_smbus_read_byte(unsigned smbus_io_base, unsigned device, unsigned address)
{
unsigned status_register;
unsigned byte;
if (smbus_wait_until_ready(smbus_io_base) < 0) {
return SMBUS_WAIT_UNTIL_READY_TIMEOUT;
}
/* setup transaction */
/* clear any lingering errors, so the transaction will run */
outb(0x1e, smbus_io_base + SMBHST_STATUS);
/* set the device I'm talking too */
outb(((device & 0x7f) << 1) | 1, smbus_io_base + SMBHST_ADDR);
/* set the command/address... */
outb(address & 0xff, smbus_io_base + SMBHST_CMD);
/* clear the data word...*/
outb(0, smbus_io_base + SMBHST_DAT);
/* start a byte read with interrupts disabled */
outb( (0x02 << 2)|(1<<6), smbus_io_base + SMBHST_CTL);
/* poll for transaction completion */
if (smbus_wait_until_done(smbus_io_base) < 0) {
return SMBUS_WAIT_UNTIL_DONE_TIMEOUT;
}
status_register = inw(smbus_io_base + SMBHST_STATUS);
/* read results of transaction */
byte = inw(smbus_io_base + SMBHST_DAT) & 0xff;
if (status_register & 0x04) {
#if 0
printk(BIOS_DEBUG, "Read fail %04x\n", status_register);
#endif
return SMBUS_ERROR;
}
return byte;
}
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