code: plan9front

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nusb/lib: make usbcmd() return value symmetic; returning size of data phase (if any) (thanks aiju)

usbcmd() with Rh2d used to return the command size (8+ndata) wile returning
only ndata for Rd2h. this changes it to always return ndata for Rh2d. it
mostly doesnt matter as Rh2d callers only check r < 0 for error, but this
makes the interface symmetic.

--- a/sys/src/cmd/nusb/lib/dev.c

+++ b/sys/src/cmd/nusb/lib/dev.c

@@ -396,6 +396,7 @@

 	}else{

 		ndata = count;

 		wp = emallocz(8+ndata, 0);

+		memmove(wp+8, data, ndata);

 	}

 	wp[0] = type;

 	wp[1] = req;

@@ -402,8 +403,6 @@

 	PUT2(wp+2, value);

 	PUT2(wp+4, index);

 	PUT2(wp+6, count);

-	if(data != nil)

-		memmove(wp+8, data, ndata);

 	if(usbdebug>2){

 		hd = hexstr(wp, ndata+8);

 		rs = reqstr(type, req);

@@ -421,7 +420,7 @@

 		dprint(2, "%s: cmd: short write: %d\n", argv0, n);

 		return -1;

 	}

-	return n;

+	return ndata;

 }

 static int

@@ -430,7 +429,7 @@

 	char *hd;

 	nb = read(d->dfd, buf, nb);

-	if(nb >0 && usbdebug > 2){

+	if(nb > 0 && usbdebug > 2){

 		hd = hexstr(buf, nb);

 		fprint(2, "%s: in[%d] %s\n", d->dir, nb, hd);

 		free(hd);

@@ -455,7 +454,7 @@

 			r = cmdreq(d, type, req, value, index, nil, count);

 		else

 			r = cmdreq(d, type, req, value, index, data, count);

-		if(r > 0){

+		if(r >= 0){

 			if((type & Rd2h) == 0)

 				break;

 			r = cmdrep(d, data, count);

@@ -469,7 +468,7 @@

 			rerrstr(err, sizeof(err));

 		sleep(Ucdelay);

 	}

-	if(r > 0 && i >= 2)

+	if(r >= 0 && i >= 2)

 		/* let the user know the device is not in good shape */

 		fprint(2, "%s: usbcmd: %s: required %d attempts (%s)\n",

 			argv0, d->dir, i, err);

--- a/sys/src/cmd/nusb/serial/ftdi.c

+++ b/sys/src/cmd/nusb/serial/ftdi.c

@@ -858,7 +858,7 @@

 		index |= p->interfc + 1;

 	dsprint(2, "serial: ftdiread %#p [%d] req: %#x val: %#x idx:%d buf:%p len:%d\n",

 		p, p->interfc, req, 0, index, buf, len);

-	res = usbcmd(ser->dev,  Rd2h | Rftdireq | Rdev, req, 0, index, buf, len);

+	res = usbcmd(ser->dev, Rd2h | Rftdireq | Rdev, req, 0, index, buf, len);

 	dsprint(2, "serial: ftdiread res:%d\n", res);

 	return res;

 }