ref: c59eb6d117c6dc99bc6e4330d3a9a3453888dee7
dir: /sys/src/cmd/audio/mixfs/mixfs.c/
#include <u.h> #include <libc.h> #include <fcall.h> #include <thread.h> #include <9p.h> enum { NBUF = 8*1024, NDELAY = 512, /* ~11.6ms */ NQUANTA = 64, /* ~1.45ms */ NCHAN = 2, FREQ = 44100, }; #define MIN(a,b) ((a)<(b)?(a):(b)) #define MAX(a,b) ((a)>(b)?(a):(b)) typedef struct Stream Stream; struct Stream { int used; int mode; int flush; int run; ulong rp; ulong wp; QLock; Rendez; }; ulong mixrp; Lock rplock; int lbbuf[NBUF][NCHAN]; int mixbuf[NBUF][NCHAN]; Lock mixlock; Stream streams[64]; char *devaudio; QLock devlock; int audiofd = -1; int volfd = -1; int volume[2] = {100, 100}; int vol64k[2] = {65536, 65536}; int s16(uchar *p) { int v; v = p[0]<<(sizeof(int)-2)*8 | p[1]<<(sizeof(int)-1)*8; v >>= (sizeof(int)-2)*8; return v; } int clip16(int v) { if(v > 0x7fff) return 0x7fff; if(v < -0x8000) return -0x8000; return v; } void closeaudiodev(void) { qlock(&devlock); if(audiofd >= 0){ close(audiofd); audiofd = -1; } qunlock(&devlock); } int reopendevs(char *name) { static char dir[] = "/dev/"; int i, n, dfd, afd; char *p; Dir *d; if(name != nil){ if(name != devaudio){ /* hack: restrict to known audio device names */ if((strncmp(name, "/dev/audio", 10) != 0 || strchr(name+10, '/') != nil) && (strncmp(name, "#u/audio", 8) != 0 || strchr(name+8, '/') != nil) && (strncmp(name, "#A/audio", 8) != 0 || strchr(name+8, '/') != nil)){ werrstr("name doesnt look like an audio device"); return -1; } } if((afd = open(name, OWRITE)) >= 0){ name = strdup(name); goto found; } if(name != devaudio) return -1; } if((dfd = open(dir, OREAD)) >= 0){ while((n = dirread(dfd, &d)) > 0){ for(i = 0; i < n; i++){ if((d[i].mode & DMDIR) != 0 || strncmp(d[i].name, "audio", 5) != 0) continue; name = smprint("%s%s", dir, d[i].name); if((afd = open(name, OWRITE)) >= 0){ close(dfd); free(d); goto found; } free(name); } free(d); } close(dfd); werrstr("no devices found"); } return -1; found: qlock(&devlock); free(devaudio); devaudio = name; audiofd = dup(afd, audiofd); qunlock(&devlock); close(afd); if(volfd >= 0){ close(volfd); volfd = -1; } if((p = utfrrune(name, '/')) != nil) p++; else p = name; if(strncmp(p, "audio", 5) == 0){ name = smprint("%.*svolume%s", (int)(p - name), name, p+5); volfd = open(name, ORDWR); free(name); } return 0; } void fsopen(Req *r) { Stream *s; if(strcmp(r->fid->file->name, "audio") != 0){ respond(r, nil); return; } for(s = streams; s < streams+nelem(streams); s++){ qlock(s); if(s->used == 0 && s->run == 0){ s->used = 1; s->mode = r->ifcall.mode; s->flush = 0; qunlock(s); r->fid->aux = s; respond(r, nil); return; } qunlock(s); } respond(r, "all streams in use"); } void fsflush(Req *r) { Fid *f = r->oldreq->fid; Stream *s; if(f->file != nil && strcmp(f->file->name, "audio") == 0 && (s = f->aux) != nil){ qlock(s); if(s->used && s->run){ s->flush = 1; rwakeup(s); } qunlock(s); } respond(r, nil); } void fsclunk(Fid *f) { Stream *s; if(f->file != nil && strcmp(f->file->name, "audio") == 0 && (s = f->aux) != nil) s->used = 0; f->aux = nil; } void audioproc(void *) { static uchar buf[NBUF*NCHAN*2]; int sweep, i, j, n, m, v; ulong rp; Stream *s; uchar *p; threadsetname("audioproc"); sweep = 0; for(;;){ m = NBUF; for(s = streams; s < streams+nelem(streams); s++){ qlock(s); if(s->run){ if(s->mode & OWRITE){ n = (long)(s->wp - mixrp); if(n <= 0 && (s->used == 0 || sweep)) s->run = 0; else if(n < m) m = n; if(n < NDELAY) rwakeup(s); } else { n = (long)(mixrp - s->rp); if(n > NBUF && (s->used == 0 || sweep)) s->run = 0; if(n > 0) rwakeup(s); } } qunlock(s); } m %= NBUF; if(m == 0){ int ms; ms = 100; if(audiofd >= 0){ if(sweep) closeaudiodev(); else { /* attempt to sleep just shortly before buffer underrun */ ms = seek(audiofd, 0, 2); ms *= 800; ms /= FREQ*NCHAN*2; } sweep = 1; } sleep(ms); continue; } sweep = 0; if(audiofd < 0 && reopendevs(devaudio) < 0){ fprint(2, "%s: reopendevs: %r\n", argv0); sleep(1000); continue; } if(m > NQUANTA) m = NQUANTA; p = buf; rp = mixrp; for(i=0; i<m; i++){ for(j=0; j<NCHAN; j++){ v = clip16(mixbuf[rp % NBUF][j])*vol64k[j] / 65536; lbbuf[rp % NBUF][j] = v; mixbuf[rp % NBUF][j] = 0; *p++ = v & 0xFF; *p++ = v >> 8; } rp++; } /* barrier */ lock(&rplock); mixrp = rp; unlock(&rplock); n = p - buf; if(write(audiofd, buf, n) != n) closeaudiodev(); } } void fsread(Req *r) { Srv *srv; int i, j, n, m, v; Stream *s; uchar *p; if(r->fid->file->aux == &volfd){ static char svol[4096]; if(r->ifcall.offset == 0){ n = 0; m = snprint(svol, sizeof(svol), "dev %s\nmix %d %d\n", devaudio?devaudio:"", volume[0], volume[1]); if(volfd < 0 || (n = pread(volfd, svol+m, sizeof(svol)-m-1, 0)) > 0) svol[m+n] = 0; } readstr(r, svol); respond(r, nil); return; } p = (uchar*)r->ofcall.data; n = r->ifcall.count; n &= ~(NCHAN*2 - 1); r->ofcall.count = n; n /= (NCHAN*2); srv = r->srv; srvrelease(srv); s = r->fid->aux; qlock(s); while(n > 0){ if(s->run == 0){ s->rp = mixrp; s->run = 1; } m = (long)(mixrp - s->rp); if(m <= 0){ if(s->flush) break; s->run = 1; rsleep(s); continue; } if(m > NBUF){ m = NBUF; s->rp = mixrp - m; } if(m > n) m = n; for(i=0; i<m; i++){ for(j=0; j<NCHAN; j++){ v = lbbuf[s->rp % NBUF][j]; *p++ = v & 0xFF; *p++ = v >> 8; } s->rp++; } n -= m; } s->flush = 0; qunlock(s); respond(r, nil); srvacquire(srv); } void fswrite(Req *r) { Srv *srv; int i, j, n, m; Stream *s; uchar *p; if(r->fid->file->aux == &volfd){ char msg[64], *f[5]; int x[2], nf; r->ofcall.count = r->ifcall.count; snprint(msg, sizeof(msg), "%.*s", utfnlen((char*)r->ifcall.data, r->ifcall.count), (char*)r->ifcall.data); nf = tokenize(msg, f, nelem(f)); if(nf > 1 && strcmp(f[0], "dev") == 0){ if(reopendevs(f[1]) < 0){ responderror(r); return; } }else if(nf > 1 && strcmp(f[0], "mix") == 0){ x[0] = atoi(f[1]); x[1] = nf < 3 ? x[0] : atoi(f[2]); if(f[1][0] == '+' || f[1][0] == '-'){ x[0] += volume[0]; x[1] += volume[1]; } volume[0] = MIN(MAX(0, x[0]), 100); volume[1] = MIN(MAX(0, x[1]), 100); /* ≈60dB dynamic range; [0-100] → [0-65536] */ vol64k[0] = 65.536 * (exp(volume[0] * 0.0690876) - 1.0); vol64k[1] = 65.536 * (exp(volume[1] * 0.0690876) - 1.0); }else if(volfd >= 0){ if(write(volfd, r->ifcall.data, r->ifcall.count) < 0){ responderror(r); return; } }else{ respond(r, "bad msg"); return; } respond(r, nil); return; } p = (uchar*)r->ifcall.data; n = r->ifcall.count; r->ofcall.count = n; n /= (NCHAN*2); srv = r->srv; srvrelease(srv); s = r->fid->aux; qlock(s); while(n > 0){ if(s->run == 0){ s->wp = mixrp; s->run = 1; } m = NBUF-1 - (long)(s->wp - mixrp); if(m <= 0){ if(s->flush) break; s->run = 1; rsleep(s); continue; } if(m > n) m = n; lock(&mixlock); for(i=0; i<m; i++){ for(j=0; j<NCHAN; j++){ mixbuf[s->wp % NBUF][j] += s16(p); p += 2; } s->wp++; } unlock(&mixlock); n -= m; } if((long)(s->wp - mixrp) >= NDELAY && !s->flush){ s->run = 1; rsleep(s); } s->flush = 0; qunlock(s); respond(r, nil); srvacquire(srv); } void fsstat(Req *r) { Stream *s; r->d.length = 0; if(r->fid->file != nil && strcmp(r->fid->file->name, "audio") == 0 && (s = r->fid->aux) != nil){ qlock(s); if(s->run){ r->d.length = (long)(s->wp - mixrp); r->d.length *= NCHAN*2; } qunlock(s); } respond(r, nil); } void fsstart(Srv *) { Stream *s; for(s=streams; s < streams+nelem(streams); s++){ s->used = s->run = 0; s->Rendez.l = &s->QLock; } proccreate(audioproc, nil, 16*1024); } void fsend(Srv *) { threadexitsall(nil); } Srv fs = { .open= fsopen, .read= fsread, .write= fswrite, .stat= fsstat, .destroyfid= fsclunk, .flush= fsflush, .start= fsstart, .end= fsend, }; void usage(void) { fprint(2, "usage: %s [-D] [-v] [-s srvname] [-m mtpt]\n", argv0); exits("usage"); } void threadmain(int argc, char **argv) { char *srv = nil; char *m, *mtpt = "/mnt/mix"; ARGBEGIN{ case 'D': chatty9p++; break; case 's': srv = EARGF(usage()); break; case 'm': mtpt = EARGF(usage()); break; default: usage(); }ARGEND; if(argc > 1) usage(); reopendevs(argv[0]); closeaudiodev(); fs.tree = alloctree(nil, nil, DMDIR|0777, nil); createfile(fs.tree->root, "audio", nil, 0666, nil); createfile(fs.tree->root, "volume", nil, 0666, &volfd); threadpostmountsrv(&fs, srv, mtpt, MREPL); bind(mtpt, "/dev", MAFTER); m = smprint("%s/audio", mtpt); bind(m, "/dev/audio", MREPL); m = smprint("%s/volume", mtpt); bind(m, "/dev/volume", MREPL); threadexits(0); }