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sdmmc: do card init in a background process after the first try

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Some mmc controllers have no card detect pin, so the only
way to detect card presence is to issue the ACMD41 which will
fail after a pretty long timeout.

To avoid mmconline() blocking, we only try to initialize the
card synchronous once, and then retry in a background process,
while returning immediately from mmconline() while the retry
is in progress.

This speeds up network boot times significantly on a raspi
without a sdcard inserted.
This commit is contained in:
cinap_lenrek 2021-11-07 17:41:57 +00:00
parent efa6937460
commit 2925fb09a6
1 changed files with 54 additions and 23 deletions
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77
sys/src/9/port/sdmmc.c
View file

@ -79,6 +79,8 @@ struct Ctlr {
u32int ocr;
u32int cid[4];
u32int csd[4];
int retry;
};
extern SDifc sdmmcifc;
@ -197,26 +199,12 @@ mmcswitchfunc(SDio *io, int arg)
}
static int
mmconline(SDunit *unit)
cardinit(Ctlr *ctl)
{
int hcs, i;
u32int r[4];
Ctlr *ctl;
SDio *io;
int hcs, i;
SDio *io = ctl->io;
ctl = unit->dev->ctlr;
io = ctl->io;
assert(unit->subno == 0);
if(waserror()){
unit->sectors = 0;
return 0;
}
if(unit->sectors != 0){
io->cmd(SEND_STATUS, ctl->rca<<Rcashift, r);
poperror();
return 1;
}
io->cmd(GO_IDLE_STATE, 0, r);
hcs = 0;
if(!waserror()){
@ -226,17 +214,14 @@ mmconline(SDunit *unit)
poperror();
}
for(i = 0; i < Inittimeout; i++){
delay(100);
tsleep(&up->sleep, return0, nil, 100);
io->cmd(APP_CMD, 0, r);
io->cmd(SD_SEND_OP_COND, hcs|V3_3, r);
if(r[0] & Powerup)
break;
}
if(i == Inittimeout){
print("sdmmc: card won't power up\n");
poperror();
if(i == Inittimeout)
return 2;
}
ctl->ocr = r[0];
io->cmd(ALL_SEND_CID, 0, r);
memmove(ctl->cid, r, sizeof ctl->cid);
@ -244,6 +229,52 @@ mmconline(SDunit *unit)
ctl->rca = r[0]>>16;
io->cmd(SEND_CSD, ctl->rca<<Rcashift, r);
memmove(ctl->csd, r, sizeof ctl->csd);
return 1;
}
static void
retryproc(void *arg)
{
Ctlr *ctl = arg;
int i = 0;
while(waserror())
;
if(i++ < ctl->retry)
cardinit(ctl);
USED(i);
ctl->retry = 0;
pexit("", 1);
}
static int
mmconline(SDunit *unit)
{
u32int r[4];
Ctlr *ctl;
SDio *io;
assert(unit->subno == 0);
ctl = unit->dev->ctlr;
io = ctl->io;
if(ctl->retry)
return 0;
if(waserror()){
unit->sectors = 0;
if(ctl->retry++ == 0)
kproc(unit->name, retryproc, ctl);
return 0;
}
if(unit->sectors != 0){
io->cmd(SEND_STATUS, ctl->rca<<Rcashift, r);
poperror();
return 1;
}
if(cardinit(ctl) != 1){
poperror();
return 2;
}
identify(unit, ctl->csd);
io->cmd(SELECT_CARD, ctl->rca<<Rcashift, r);
io->cmd(SET_BLOCKLEN, unit->secsize, r);
@ -265,13 +296,13 @@ mmcrctl(SDunit *unit, char *p, int l)
Ctlr *ctl;
int i, n;
ctl = unit->dev->ctlr;
assert(unit->subno == 0);
if(unit->sectors == 0){
mmconline(unit);
if(unit->sectors == 0)
return 0;
}
ctl = unit->dev->ctlr;
n = snprint(p, l, "rca %4.4ux ocr %8.8ux\ncid ", ctl->rca, ctl->ocr);
for(i = nelem(ctl->cid)-1; i >= 0; i--)
n += snprint(p+n, l-n, "%8.8ux", ctl->cid[i]);