static int
ow_enumerate(device_t dev, ow_enum_fn *enumfp, ow_found_fn *foundfp)
{
device_t lldev = device_get_parent(dev);
int first, second, i, dir, prior, last, err, retries;
uint64_t probed, last_mask;
int sanity = 10;
prior = -1;
last_mask = 0;
retries = 0;
last = -2;
err = ow_acquire_bus(dev, dev, OWN_DONTWAIT);
if (err != 0)
return err;
while (last != -1) {
if (sanity-- < 0) {
printf("Reached the sanity limit\n");
return EIO;
}
again:
probed = 0;
last = -1;
/*
* See AN397 section 5.II.C.3 for the algorithm (though a bit
* poorly stated). The search command forces each device to
* send ROM ID bits one at a time (first the bit, then the
* complement) the master (us) sends back a bit. If the
* device's bit doesn't match what we send back, that device
* stops sending bits back. So each time through we remember
* where we made the last decision (always 0). If there's a
* conflict there this time (and there will be in the absence
* of a hardware failure) we go with 1. This way, we prune the
* devices on the bus and wind up with a unique ROM. We know
* we're done when we detect no new conflicts. The same
* algorithm is used for devices in alarm state as well.
*
* In addition, experience has shown that sometimes devices
* stop responding in the middle of enumeration, so try this
* step again a few times when that happens. It is unclear if
* this is due to a nosiy electrical environment or some odd
* timing issue.
*/
/*
* The enumeration command should be successfully sent, if not,
* we have big issues on the bus so punt. Lower layers report
* any unusual errors, so we don't need to here.
*/
err = enumfp(dev, dev);
if (err != 0)
return (err);
for (i = 0; i < 64; i++) {
OWLL_READ_DATA(lldev, &timing_regular, &first);
OWLL_READ_DATA(lldev, &timing_regular, &second);
switch (first | second << 1) {
case 0: /* Conflict */
if (i < prior)
dir = (last_mask >> i) & 1;
else
dir = i == prior;
if (dir == 0)
last = i;
break;
case 1: /* 1 then 0 -> 1 for all */
dir = 1;
break;
case 2: /* 0 then 1 -> 0 for all */
dir = 0;
break;
case 3:
/*
* No device responded. This is unexpected, but
* experience has shown that on some platforms
* we miss a timing window, or otherwise have
* an issue. Start this step over. Since we've
* not updated prior yet, we can just jump to
* the top of the loop for a re-do of this step.
*/
printf("oops, starting over\n");
if (++retries > 5)
return (EIO);
goto again;
default: /* NOTREACHED */
__unreachable();
}
if (dir) {
OWLL_WRITE_ONE(lldev, &timing_regular);
probed |= 1ull << i;
} else {
OWLL_WRITE_ZERO(lldev, &timing_regular);
}
}
retries = 0;
foundfp(dev, probed);
last_mask = probed;
prior = last;
}
/*
* Like fgets, but go through the chain of compilation units chaining them
* together. Empty strings and files are ignored.
*/
char *
cu_fgets(char *buf, int n, int *more)
{
static enum {ST_EOF, ST_FILE, ST_STRING} state = ST_EOF;
static FILE *f; /* Current open file */
static char *s; /* Current pointer inside string */
static char string_ident[30];
char *p;
again:
switch (state) {
case ST_EOF:
if (script == NULL) {
if (more != NULL)
*more = 0;
return (NULL);
}
linenum = 0;
switch (script->type) {
case CU_FILE:
if ((f = fopen(script->s, "r")) == NULL)
err(1, "%s", script->s);
fname = script->s;
state = ST_FILE;
goto again;
case CU_STRING:
if (((size_t)snprintf(string_ident,
sizeof(string_ident), "\"%s\"", script->s)) >=
sizeof(string_ident) - 1)
(void)strcpy(string_ident +
sizeof(string_ident) - 6, " ...\"");
fname = string_ident;
s = script->s;
state = ST_STRING;
goto again;
default:
__unreachable();
}
case ST_FILE:
if ((p = fgets(buf, n, f)) != NULL) {
linenum++;
if (linenum == 1 && buf[0] == '#' && buf[1] == 'n')
nflag = 1;
if (more != NULL)
*more = !feof(f);
return (p);
}
script = script->next;
(void)fclose(f);
state = ST_EOF;
goto again;
case ST_STRING:
if (linenum == 0 && s[0] == '#' && s[1] == 'n')
nflag = 1;
p = buf;
for (;;) {
if (n-- <= 1) {
*p = '\0';
linenum++;
if (more != NULL)
*more = 1;
return (buf);
}
switch (*s) {
case '\0':
state = ST_EOF;
if (s == script->s) {
script = script->next;
goto again;
} else {
script = script->next;
*p = '\0';
linenum++;
if (more != NULL)
*more = 0;
return (buf);
}
case '\n':
*p++ = '\n';
*p = '\0';
s++;
linenum++;
if (more != NULL)
*more = 0;
return (buf);
default:
*p++ = *s++;
}
}
}
/* NOTREACHED */
return (NULL);
}
