從start_armboot routine來了解u-boot--PART3

今天我們來看這個init_baudrate, /* initialze baudrate settings */(5)

首先把code列出如下：

static int init_baudrate (void)
{
char tmp[64]; /* long enough for environment variables */
int i = getenv_r ("baudrate", tmp, sizeof (tmp));
gd->bd->bi_baudrate = gd->baudrate = (i > 0)
? (int) simple_strtoul (tmp, NULL, 10)
: CONFIG_BAUDRATE;
return (0);
}

#define CONFIG_BAUDRATE 115200

#define CONFIG_ENV_SIZE ENVSIZE(dev_current)

int getenv_r (char *name, char *buf, unsigned len)
{
int i, nxt;
for (i=0; env_get_char(i) != '\0'; i=nxt+1) {
int val, n;
for (nxt=i; env_get_char(nxt) != '\0'; ++nxt) {
if (nxt >= CONFIG_ENV_SIZE) {
return (-1);
}
}
if ((val=envmatch((uchar *)name, i)) <>n = 0;
while ((len > n++) && (*buf++ = env_get_char(val++)) != '\0')
;
if (len == n) *buf = '\0';
return (n);
}
return (-1);
}

unsigned long simple_strtoul(const char *cp,char **endp,unsigned int base)
{
unsigned long result = 0,value;
if (*cp == '0') {
cp++;
if ((*cp == 'x') && isxdigit(cp[1])) {
base = 16;
cp++;
}
if (!base) {
base = 8;
}
}
if (!base) {
base = 10;
}
while (isxdigit(*cp) && (value = isdigit(*cp) ? *cp-'0' : (islower(*cp) ? toupper(*cp) : *cp)-'A'+10) < base) {
result = result*base + value;
cp++;
}
if (endp)
*endp = (char *)cp;
return result;
}