/****************************************************************************
* get_cmos_checksum_info
*
* Get layout information for CMOS checksum.
****************************************************************************/
static void get_cmos_checksum_info(void)
{
const cmos_entry_t *e;
struct cmos_checksum *checksum;
cmos_checksum_layout_t layout;
unsigned index, index2;
checksum = (struct cmos_checksum *)next_cmos_rec((const struct lb_record *)first_cmos_table_enum(), LB_TAG_OPTION_CHECKSUM);
if (checksum != NULL) { /* We are lucky. The coreboot table hints us to the checksum.
* We might have to check the type field here though.
*/
layout.summed_area_start = checksum->range_start;
layout.summed_area_end = checksum->range_end;
layout.checksum_at = checksum->location;
try_convert_checksum_layout(&layout);
cmos_checksum_start = layout.summed_area_start;
cmos_checksum_end = layout.summed_area_end;
cmos_checksum_index = layout.checksum_at;
return;
}
if ((e = find_cmos_entry(checksum_param_name)) == NULL)
return;
/* If we get here, we are unlucky. The CMOS option table contains the
* location of the CMOS checksum. However, there is no information
* regarding which bytes of the CMOS area the checksum is computed over.
* Thus we have to hope our presets will be fine.
*/
if (e->bit % 8) {
fprintf(stderr,
"%s: Error: CMOS checksum is not byte-aligned.\n",
prog_name);
exit(1);
}
index = e->bit / 8;
index2 = index + 1; /* The CMOS checksum occupies 16 bits. */
if (verify_cmos_byte_index(index) || verify_cmos_byte_index(index2)) {
fprintf(stderr,
"%s: Error: CMOS checksum location out of range.\n",
prog_name);
exit(1);
}
if (((index >= cmos_checksum_start) && (index <= cmos_checksum_end)) ||
(((index2) >= cmos_checksum_start)
&& ((index2) <= cmos_checksum_end))) {
fprintf(stderr,
"%s: Error: CMOS checksum overlaps checksummed area.\n",
prog_name);
exit(1);
}
cmos_checksum_index = index;
}
/****************************************************************************
* checksum_layout_to_bytes
*
* On entry, '*layout' contains checksum-related layout information expressed
* in bits. Perform sanity checking on the information and convert it from
* bit positions to byte positions. Return OK on success or an error code if
* a sanity check fails.
****************************************************************************/
int checksum_layout_to_bytes(cmos_checksum_layout_t * layout)
{
unsigned start, end, index;
start = layout->summed_area_start;
end = layout->summed_area_end;
index = layout->checksum_at;
if (start % 8)
return LAYOUT_SUMMED_AREA_START_NOT_ALIGNED;
if ((end % 8) != 7)
return LAYOUT_SUMMED_AREA_END_NOT_ALIGNED;
if (index % 8)
return LAYOUT_CHECKSUM_LOCATION_NOT_ALIGNED;
if (end <= start)
return LAYOUT_INVALID_SUMMED_AREA;
/* Convert bit positions to byte positions. */
start /= 8;
end /= 8; /* equivalent to "end = ((end - 7) / 8)" */
index /= 8;
if (verify_cmos_byte_index(start) || verify_cmos_byte_index(end))
return LAYOUT_SUMMED_AREA_OUT_OF_RANGE;
if (verify_cmos_byte_index(index))
return LAYOUT_CHECKSUM_LOCATION_OUT_OF_RANGE;
/* checksum occupies 16 bits */
if (areas_overlap(start, end - start + 1, index, index + 1))
return LAYOUT_CHECKSUM_OVERLAPS_SUMMED_AREA;
layout->summed_area_start = start;
layout->summed_area_end = end;
layout->checksum_at = index;
return OK;
}
static unsigned char cmos_hal_read(unsigned index)
{
unsigned short port_0, port_1;
assert(!verify_cmos_byte_index(index));
if (index < 128) {
port_0 = 0x70;
port_1 = 0x71;
} else {
port_0 = 0x72;
port_1 = 0x73;
}
OUTB(index, port_0);
return INB(port_1);
}
static void cmos_hal_write(unsigned index, unsigned char value)
{
unsigned short port_0, port_1;
assert(!verify_cmos_byte_index(index));
if (index < 128) {
port_0 = 0x70;
port_1 = 0x71;
} else {
port_0 = 0x72;
port_1 = 0x73;
}
OUTB(index, port_0);
OUTB(value, port_1);
}
