ref: da7d6df6faf18e289fe0f3f61524dcc7fddeef18
dir: /os/sa1110/devpower.c/
/*
* power management
*/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
typedef struct Power Power;
typedef struct Puser Puser;
enum{
Qdir,
Qctl,
Qdata
};
static
Dirtab powertab[]={
".", {Qdir, 0, QTDIR}, 0, 0500,
"powerctl", {Qctl, 0}, 0, 0600,
"powerdata", {Qdata, 0}, 0, 0666,
};
struct Puser {
Ref;
ulong alarm; /* real time clock alarm time, if non-zero */
QLock rl; /* mutual exclusion to protect r */
Rendez r; /* wait for event of interest */
int state; /* shutdown state of this process */
Puser* next;
};
enum{
Pwridle,
Pwroff,
Pwrack
};
static struct {
QLock;
Puser *list;
Lock l; /* protect shutdown, nwaiting */
int shutdown; /* non-zero if currently shutting down */
int nwaiting; /* waiting for this many processes */
Rendez ackr; /* wait here for all acks */
} pwrusers;
static Chan*
powerattach(char* spec)
{
return devattach(L'↓', spec);
}
static int
powerwalk(Chan* c, char* name)
{
return devwalk(c, name, powertab, nelem(powertab), devgen);
}
static void
powerstat(Chan* c, char* db)
{
devstat(c, db, powertab, nelem(powertab), devgen);
}
static Chan*
poweropen(Chan* c, int omode)
{
Puser *p;
if(c->qid.type & QTDIR)
return devopen(c, omode, powertab, nelem(powertab), devgen);
switch(c->qid.path){
case Qdata:
p = mallocz(sizeof(Puser), 1);
if(p == nil)
error(Enovmem);
p->state = Pwridle;
p->ref = 1;
if(waserror()){
free(p);
nexterror();
}
c = devopen(c, omode, powertab, nelem(powertab), devgen);
c->aux = p;
qlock(&pwrusers);
p->next = pwrusers.list;
pwrusers.list = p; /* note: must place on front of list for correct shutdown ordering */
qunlock(&pwrusers);
poperror();
break;
case Qctl:
c = devopen(c, omode, powertab, nelem(powertab), devgen);
break;
}
return c;
}
static Chan *
powerclone(Chan *c, Chan *nc)
{
Puser *p;
nc = devclone(c, nc);
if((p = nc->aux) != nil)
incref(p);
return nc;
}
static void
powerclose(Chan* c)
{
Puser *p, **l;
if(c->qid.type & QTDIR || (c->flag & COPEN) == 0)
return;
p = c->aux;
if(p != nil && decref(p) == 0){
/* TO DO: cancel alarm */
qlock(&pwrusers);
for(l = &pwrusers.list; *l != nil; l = &(*l)->next)
if(*l == p){
*l = p->next;
break;
}
qunlock(&pwrusers);
free(p);
}
}
static int
isshutdown(void *a)
{
return ((Puser*)a)->state == Pwroff;
}
static long
powerread(Chan* c, void* a, long n, vlong offset)
{
Puser *p;
char *msg;
switch(c->qid.path & ~CHDIR){
case Qdir:
return devdirread(c, a, n, powertab, nelem(powertab), devgen);
case Qdata:
p = c->aux;
for(;;){
if(!canqlock(&p->rl))
error(Einuse); /* only one reader at a time */
if(waserror()){
qunlock(&p->rl);
nexterror();
}
sleep(&p->r, isshutdown, p);
poperror();
qunlock(&p->rl);
msg = nil;
lock(p);
if(p->state == Pwroff){
msg = "power off";
p->state = Pwrack;
}
unlock(p);
if(msg != nil)
return readstr(offset, a, n, msg);
}
break;
case Qctl:
default:
n=0;
break;
}
return n;
}
static int
alldown(void*)
{
return pwrusers.nwaiting == 0;
}
static long
powerwrite(Chan* c, void *a, long n, vlong)
{
Cmdbuf *cmd;
Puser *p;
if(c->qid.type & QTDIR)
error(Ebadusefd);
cmd = parsecmd(a, n);
if(waserror()){
free(cmd);
nexterror();
}
switch(c->qid.path & ~CHDIR){
case Qdata:
p = c->aux;
if(cmd->nf < 2)
error(Ebadarg);
if(strcmp(cmd->f[0], "ack") == 0){
if(strcmp(cmd->f[1], "power") == 0){
lock(p);
if(p->state == Pwrack){
lock(&pwrusers.l);
if(pwrusers.shutdown && pwrusers.nwaiting > 0)
pwrusers.nwaiting--;
unlock(&pwrusers.l);
wakeup(&pwrusers.ackr);
p->state = Pwridle;
}
unlock(p);
}else
error(Ebadarg);
}else if(strcmp(cmd->f[0], "alarm") == 0){
/* set alarm */
}else
error(Ebadarg);
break;
case Qctl:
if(cmd->nf < 1)
error(Ebadarg);
if(strcmp(cmd->f[0], "suspend") == 0){
/* start the suspend action */
qlock(&pwrusers);
//powersuspend(0); /* calls poweringdown, then archsuspend() */
qunlock(&pwrusers);
}else if(strcmp(cmd->f[0], "shutdown") == 0){
/* go to it */
qlock(&pwrusers);
if(waserror()){
lock(&pwrusers.l);
pwrusers.shutdown = 0; /* hard luck for those already notified */
unlock(&pwrusers.l);
qunlock(&pwrusers);
nexterror();
}
lock(&pwrusers.l);
pwrusers.shutdown = 1;
pwrusers.nwaiting = 0;
unlock(&pwrusers.l);
for(p = pwrusers.list; p != nil; p = p->next){
lock(p);
if(p->state == Pwridle){
p->state = Pwroff;
lock(&pwrusers.l);
pwrusers.nwaiting++;
unlock(&pwrusers.l);
}
unlock(p);
wakeup(&p->r);
/* putting the tsleep here does each in turn; move out of loop to multicast */
tsleep(&pwrusers.ackr, alldown, nil, 1000);
}
poperror();
qunlock(&pwrusers);
//powersuspend(1);
}else
error(Ebadarg);
free(cmd);
break;
default:
error(Ebadusefd);
}
poperror();
return n;
}
/*
* device-level power management: suspend/resume/shutdown
*/
struct Power {
void (*f)(int);
Power* prev;
Power* next;
};
static struct {
Lock;
Power list;
} power;
void
powerenablereset(void)
{
power.list.next = power.list.prev = &power.list;
power.list.f = (void*)-1; /* something not nil */
}
void
powerenable(void (*f)(int))
{
Power *p, *l;
p = malloc(sizeof(*p));
p->f = f;
p->prev = nil;
p->next = nil;
ilock(&power);
for(l = power.list.next; l != &power.list; l = l->next)
if(l->f == f){
iunlock(&power);
free(p);
return;
}
l = &power.list;
p->prev = l->prev;
l->prev = p;
p->next = l;
p->prev->next = p;
iunlock(&power);
}
void
powerdisable(void (*f)(int))
{
Power *l;
ilock(&power);
for(l = power.list.next; l != &power.list; l = l->next)
if(l->f == f){
l->prev->next = l->next;
l->next->prev = l->prev;
free(l);
break;
}
iunlock(&power);
}
/*
* interrupts are assumed off so there's no need to lock
*/
void
poweringup(void)
{
Power *l;
for(l = power.list.next; l != &power.list; l = l->next)
(*l->f)(1);
}
void
poweringdown(void)
{
Power *l;
for(l = power.list.prev; l != &power.list; l = l->prev)
(*l->f)(0);
}
Dev powerdevtab = {
L'↓',
"power",
devreset,
devinit,
powerattach,
devdetach,
powerclone,
powerwalk,
powerstat,
poweropen,
devcreate,
powerclose,
powerread,
devbread,
powerwrite,
devbwrite,
devremove,
devwstat,
};