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/* SPDX-License-Identifier: GPL-2.0-only */
#include <console/console.h>
#include <string.h>
#include <cbfs.h>
#include <option.h>
#include <pc80/mc146818rtc.h>
#include <types.h>
/* option_table.h is autogenerated */
#include "option_table.h"
/* Don't warn for checking >= LB_CKS_RANGE_START even though it may be 0. */
#pragma GCC diagnostic ignored "-Wtype-limits"
/*
* This routine returns the value of the requested bits.
* input bit = bit count from the beginning of the CMOS image
* length = number of bits to include in the value
* ret = a character pointer to where the value is to be returned
* returns CB_SUCCESS = successful, cb_err code if an error occurred
*/
static enum cb_err get_cmos_value(unsigned long bit, unsigned long length,
void *vret)
{
unsigned char *ret;
unsigned long byte, byte_bit;
unsigned long i;
unsigned char uchar;
/*
* The table is checked when it is built to ensure all
* values are valid.
*/
ret = vret;
byte = bit / 8; /* find the byte where the data starts */
byte_bit = bit % 8; /* find the bit in the byte where the data starts */
if (length < 9) { /* one byte or less */
uchar = cmos_read(byte); /* load the byte */
uchar >>= byte_bit; /* shift the bits to byte align */
/* clear unspecified bits */
ret[0] = uchar & ((1 << length) - 1);
} else { /* more than one byte so transfer the whole bytes */
for (i = 0; length; i++, length -= 8, byte++) {
/* load the byte */
ret[i] = cmos_read(byte);
}
}
return CB_SUCCESS;
}
static struct cmos_option_table *get_cmos_layout(void)
{
static struct cmos_option_table *ct = NULL;
/*
* In case VBOOT is enabled and this function is called from SMM,
* we have multiple CMOS layout files and to locate them we'd need to
* include VBOOT into SMM...
*
* Support only one CMOS layout in the RO CBFS for now.
*/
if (!ct)
ct = cbfs_ro_map("cmos_layout.bin", NULL);
if (!ct)
printk(BIOS_ERR, "RTC: cmos_layout.bin could not be found. "
"Options are disabled\n");
return ct;
}
static struct cmos_entries *find_cmos_entry(struct cmos_option_table *ct, const char *name)
{
/* Figure out how long name is */
const size_t namelen = strnlen(name, CMOS_MAX_NAME_LENGTH);
struct cmos_entries *ce;
/* Find the requested entry record */
ce = (struct cmos_entries *)((unsigned char *)ct + ct->header_length);
for (; ce->tag == LB_TAG_OPTION;
ce = (struct cmos_entries *)((unsigned char *)ce + ce->size)) {
if (memcmp(ce->name, name, namelen) == 0)
return ce;
}
return NULL;
}
enum cb_err cmos_get_option(void *dest, const char *name)
{
struct cmos_option_table *ct;
struct cmos_entries *ce;
ct = get_cmos_layout();
if (!ct)
return CB_CMOS_LAYOUT_NOT_FOUND;
ce = find_cmos_entry(ct, name);
if (!ce) {
printk(BIOS_DEBUG, "No CMOS option '%s'.\n", name);
return CB_CMOS_OPTION_NOT_FOUND;
}
if (!cmos_checksum_valid(LB_CKS_RANGE_START, LB_CKS_RANGE_END, LB_CKS_LOC))
return CB_CMOS_CHECKSUM_INVALID;
if (get_cmos_value(ce->bit, ce->length, dest) != CB_SUCCESS)
return CB_CMOS_ACCESS_ERROR;
return CB_SUCCESS;
}
static enum cb_err set_cmos_value(unsigned long bit, unsigned long length,
void *vret)
{
unsigned char *ret;
unsigned long byte, byte_bit;
unsigned long i;
unsigned char uchar, mask;
unsigned int chksum_update_needed = 0;
ret = vret;
byte = bit / 8; /* find the byte where the data starts */
byte_bit = bit % 8; /* find the bit where the data starts */
if (length <= 8) { /* one byte or less */
mask = (1 << length) - 1;
mask <<= byte_bit;
uchar = cmos_read(byte);
uchar &= ~mask;
uchar |= (ret[0] << byte_bit);
cmos_write(uchar, byte);
if (byte >= LB_CKS_RANGE_START && byte <= LB_CKS_RANGE_END)
chksum_update_needed = 1;
} else { /* more that one byte so transfer the whole bytes */
if (byte_bit || length % 8)
return CB_ERR_ARG;
for (i = 0; length; i++, length -= 8, byte++) {
cmos_write(ret[i], byte);
if (byte >= LB_CKS_RANGE_START &&
byte <= LB_CKS_RANGE_END)
chksum_update_needed = 1;
}
}
if (chksum_update_needed) {
cmos_set_checksum(LB_CKS_RANGE_START, LB_CKS_RANGE_END,
LB_CKS_LOC);
}
return CB_SUCCESS;
}
enum cb_err cmos_set_option(const char *name, void *value)
{
struct cmos_option_table *ct;
struct cmos_entries *ce;
unsigned long length;
ct = get_cmos_layout();
if (!ct)
return CB_CMOS_LAYOUT_NOT_FOUND;
ce = find_cmos_entry(ct, name);
if (!ce) {
printk(BIOS_DEBUG, "WARNING: No CMOS option '%s'.\n", name);
return CB_CMOS_OPTION_NOT_FOUND;
}
length = ce->length;
if (ce->config == 's') {
length = MAX(strlen((const char *)value) * 8, ce->length - 8);
/* make sure the string is null terminated */
if (set_cmos_value(ce->bit + ce->length - 8, 8, &(u8[]){0})
!= CB_SUCCESS)
return CB_CMOS_ACCESS_ERROR;
}
if (set_cmos_value(ce->bit, length, value) != CB_SUCCESS)
return CB_CMOS_ACCESS_ERROR;
return CB_SUCCESS;
}
int cmos_lb_cks_valid(void)
{
return cmos_checksum_valid(LB_CKS_RANGE_START, LB_CKS_RANGE_END, LB_CKS_LOC);
}
void sanitize_cmos(void)
{
const unsigned char *cmos_default;
const bool cmos_need_reset =
CONFIG(STATIC_OPTION_TABLE) || cmos_error() || !cmos_lb_cks_valid();
size_t length = 128;
size_t i;
if (CONFIG(TPM_MEASURED_BOOT) || cmos_need_reset) {
cmos_default = cbfs_map("cmos.default", &length);
if (!cmos_default || !cmos_need_reset)
return;
u8 control_state = cmos_disable_rtc();
for (i = 14; i < MIN(128, length); i++)
cmos_write_inner(cmos_default[i], i);
cmos_restore_rtc(control_state);
}
}
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