#include <thread.h>

#include <u.h>
#include <libc.h>
#include <thread.h>
#include <fcall.h>
#include <9p.h>
#include "usb.h"
#include "dat.h"
#include "fns.h"

enum {
Qroot,
Qusbevent,
Qmax
};

char *names[] = {
"",
"usbevent",
};

static char Enonexist[] = "does not exist";

typedef struct Event Event;

struct Event {
Dev *dev; /* the device producing the event,
dev->aux points to Fid processing the event */
char *data;
int len;
Event *link;
int ref; /* number of readers which will read this one
the next time they'll read */
int prev; /* number of events pointing to this one with
their link pointers */
};

static Event *evlast;
static Req *reqfirst, *reqlast;
static QLock evlock;

static void
addreader(Req *req)
{
req->aux = nil;
if(reqfirst == nil)
reqfirst = req;
else
reqlast->aux = req;
reqlast = req;
}

static void
fulfill(Req *req, Event *e)
{
int n;

n = e->len;
if(n > req->ifcall.count)
n = req->ifcall.count;
memmove(req->ofcall.data, e->data, n);
req->ofcall.count = n;
}

static void
initevent(void)
{
evlast = emallocz(sizeof(Event), 1);
}

static Event*
putevent(Event *e)
{
Event *ee;

ee = e->link;
if(e->ref || e->prev)
return ee;
ee->prev--;
closedev(e->dev);
free(e->data);
free(e);
return ee;
}

static void
procreqs(void)
{
Req *r, *p, *x;
Event *e;
Fid *f;

Loop:
for(p = nil, r = reqfirst; r != nil; p = r, r = x){
x = r->aux;
f = r->fid;
e = f->aux;
if(e == evlast)
continue;
if(e->dev->aux == f){
e->dev->aux = nil; /* release device */
e->ref--;
e = putevent(e);
e->ref++;
f->aux = e;
goto Loop;
}
if(e->dev->aux == nil){
e->dev->aux = f; /* claim device */
if(x == nil)
reqlast = p;
if(p == nil)
reqfirst = x;
else
p->aux = x;
r->aux = nil;
fulfill(r, e);
respond(r, nil);
goto Loop;
}
}
}

static void
pushevent(Dev *d, char *data)
{
Event *e;

qlock(&evlock);
e = evlast;
evlast = emallocz(sizeof(Event), 1);
incref(d);
e->dev = d;
e->data = data;
e->len = strlen(data);
e->link = evlast;
evlast->prev++;
procreqs();
putevent(e);
qunlock(&evlock);
}

static int
dirgen(int n, Dir *d, void *)
{
if(n >= Qmax - 1)
return -1;
d->qid.path = n + 1;
d->qid.vers = 0;
if(n >= 0){
d->qid.type = 0;
d->mode = 0444;
}else{
d->qid.type = QTDIR;
d->mode = 0555 | DMDIR;
}
d->uid = estrdup9p(getuser());
d->gid = estrdup9p(d->uid);
d->muid = estrdup9p(d->uid);
d->name = estrdup9p(names[n+1]);
d->atime = d->mtime = time(0);
d->length = 0;
return 0;
}

static void
usbdattach(Req *req)
{
req->fid->qid = (Qid) {Qroot, 0, QTDIR};
req->ofcall.qid = req->fid->qid;
respond(req, nil);
}

static char *
usbdwalk(Fid *fid, char *name, Qid *qid)
{
int i;

if(fid->qid.path != Qroot)
return "not a directory";
if(strcmp(name, "..") == 0){
*qid = fid->qid;
return nil;
}
for(i = Qroot+1; i < Qmax; i++)
if(strcmp(name, names[i]) == 0){
fid->qid = (Qid) {i, 0, 0};
*qid = fid->qid;
return nil;
}
return Enonexist;
}

static void
usbdread(Req *req)
{
switch((long)req->fid->qid.path){
case Qroot:
dirread9p(req, dirgen, nil);
respond(req, nil);
break;
case Qusbevent:
qlock(&evlock);
addreader(req);
procreqs();
qunlock(&evlock);
break;
default:
respond(req, Enonexist);
break;
}
}

static void
usbdstat(Req *req)
{
if(dirgen(req->fid->qid.path - 1, &req->d, nil) < 0)
respond(req, Enonexist);
else
respond(req, nil);
}

static char *
formatdev(Dev *d, int type)
{
Usbdev *u = d->usb;
return smprint("%s %d %.4x %.4x %.6lx %s\n",
type ? "detach" : "attach",
d->id, u->vid, u->did, u->csp,
d->hname != nil ? d->hname : "");
}

static void
enumerate(Event **l)
{
extern Hub *hubs;

Event *e;
Hub *h;
Port *p;
Dev *d;
int i;

for(h = hubs; h != nil; h = h->next){
for(i = 1; i <= h->nport; i++){
p = &h->port[i];
d = p->dev;
if(d == nil || d->usb == nil || p->hub != nil)
continue;
e = emallocz(sizeof(Event), 1);
incref(d);
e->dev = d;
e->data = formatdev(d, 0);
e->len = strlen(e->data);
e->prev = 1;
*l = e;
l = &e->link;

}
}
*l = evlast;
evlast->prev++;
}

static void
usbdopen(Req *req)
{
extern QLock hublock;

if(req->fid->qid.path == Qusbevent){
Event *e;

qlock(&hublock);
qlock(&evlock);

enumerate(&e);
e->prev--;
e->ref++;
req->fid->aux = e;

qunlock(&evlock);
qunlock(&hublock);
}
respond(req, nil);
}

static void
usbddestroyfid(Fid *fid)
{
if(fid->qid.path == Qusbevent){
Event *e;

qlock(&evlock);
e = fid->aux;
if(e != nil){
fid->aux = nil;
if(e->dev != nil && e->dev->aux == fid){
e->dev->aux = nil; /* release device */
procreqs();
}
e->ref--;
while(e->ref == 0 && e->prev == 0 && e != evlast)
e = putevent(e);
}
qunlock(&evlock);
}
}

static void
usbdflush(Req *req)
{
Req *r, *p, *x;

qlock(&evlock);
for(p = nil, r = reqfirst; r != nil; p = r, r = x){
x = r->aux;
if(r == req->oldreq){
if(x == nil)
reqlast = p;
if(p == nil)
reqfirst = x;
else
p->aux = x;
r->aux = nil;
respond(r, "interrupted");
break;
}
}
qunlock(&evlock);
respond(req, nil);
}

static void
usbdstart(Srv*)
{
switch(rfork(RFPROC|RFMEM|RFNOWAIT)){
case -1: sysfatal("rfork: %r");
case 0: work(); exits(nil);
}
}

static void
usbdend(Srv*)
{
postnote(PNGROUP, getpid(), "shutdown");
}

Srv usbdsrv = {
.start = usbdstart,
.end = usbdend,
.attach = usbdattach,
.walk1 = usbdwalk,
.read = usbdread,
.stat = usbdstat,
.open = usbdopen,
.flush = usbdflush,
.destroyfid = usbddestroyfid,
};

static void
assignhname(Dev *dev)
{
extern Hub *hubs;
char buf[64];
Usbdev *ud;
Hub *h;
int i;

ud = dev->usb;

/* build string of device unique stuff */
snprint(buf, sizeof(buf), "%.4x%.4x%.4x%.6lx%s",
ud->vid, ud->did, ud->dno, ud->csp, ud->serial);

hname(buf);

/* check for collisions */
for(h = hubs; h != nil; h = h->next){
for(i = 1; i <= h->nport; i++){
if(h->port[i].dev == nil)
continue;
if(h->port[i].dev->hname == nil || h->port[i].dev == dev)
continue;
if(strcmp(h->port[i].dev->hname, buf) == 0){
dev->hname = smprint("%s%d", buf, dev->id);
return;
}
}
}
dev->hname = strdup(buf);
}

int
attachdev(Port *p)
{
Dev *d = p->dev;
int id;

if(d->usb->class == Clhub){
/*
* Hubs are handled directly by this process avoiding
* concurrent operation so that at most one device
* has the config address in use.
* We cancel kernel debug for these eps. too chatty.
*/
if((p->hub = newhub(d->dir, d)) == nil)
return -1;
return 0;
}

/* create all endpoint files for default conf #1 */
for(id=1; id<nelem(d->usb->ep); id++){
Ep *ep = d->usb->ep[id];
if(ep != nil && ep->conf != nil && ep->conf->cval == 1){
Dev *epd = openep(d, id);
if(epd != nil)
closedev(epd);
}
}

/* close control endpoint so driver can open it */
close(d->dfd);
d->dfd = -1;

/* assign stable name based on device descriptor */
assignhname(d);

/* set device info for ctl file */
devctl(d, "info %s csp %#08lux vid %#.4ux did %#.4ux %q %q %s",
classname(Class(d->usb->csp)), d->usb->csp, d->usb->vid, d->usb->did,
d->usb->vendor, d->usb->product, d->hname);

pushevent(d, formatdev(d, 0));
return 0;
}

void
detachdev(Port *p)
{
Dev *d = p->dev;

if(d->usb->class == Clhub)
return;
pushevent(d, formatdev(d, 1));
}

/*
* we create /env/usbbusy on startup and once all devices have been
* enumerated and readers have consumed all the events, we remove the
* file so nusbrc can continue.
*/
static int busyfd = -1;

void
checkidle(void)
{
if(busyfd < 0 || reqlast == nil || evlast == nil || evlast->prev > 0)
return;

close(busyfd);
busyfd = -1;
}

void
main(int argc, char **argv)
{
int fd, i, nd;
char *fn;
Dir *d;

ARGBEGIN {
case 'D':
chatty9p++;
break;
case 'd':
usbdebug++;
break;
} ARGEND;

quotefmtinstall();
fmtinstall('U', Ufmt);
initevent();

hubs = nil;
if(argc == 0){
if((fd = open("/dev/usb", OREAD)) < 0)
sysfatal("/dev/usb: %r");
nd = dirreadall(fd, &d);
close(fd);
for(i = 0; i < nd; i++){
if(strcmp(d[i].name, "ctl") != 0){
fn = smprint("/dev/usb/%s", d[i].name);
newhub(fn, nil);
free(fn);
}
}
free(d);
}else {
for(i = 0; i < argc; i++)
newhub(argv[i], nil);
}

if(hubs == nil)
sysfatal("no hubs");

busyfd = create("/env/usbbusy", ORCLOSE, 0600);
postsharesrv(&usbdsrv, nil, "usb", "usbd");
exits(nil);
}