Move buffer management into kbd and kbdmux drivers.

These two drivers seem to be the last consumers of clists. clists are
quite overengineered for simple circular buffers, so I'm adding similar
buffer management routines to the kbd and kbdmux drivers. The input
buffer is now part of the softc structures, instead of having
dynamically allocated cblocks.

1 files changed, 51 insertions, 23 deletions

diff --git a/sys/dev/kbd/kbd.c b/sys/dev/kbd/kbd.c
index 753269a..851f677 100644
--- a/sys/dev/kbd/kbd.c
+++ b/sys/dev/kbd/kbd.c
@@ -34,7 +34,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/systm.h>
 #include <sys/kernel.h>
 #include <sys/malloc.h>
-#include <sys/clist.h>
 #include <sys/conf.h>
 #include <sys/fcntl.h>
 #include <sys/poll.h>
@@ -50,11 +49,16 @@ __FBSDID("$FreeBSD$");
 
 #define KBD_INDEX(dev)	dev2unit(dev)
 
+#define KB_QSIZE	512
+#define KB_BUFSIZE	64
+
 typedef struct genkbd_softc {
 	int		gkb_flags;	/* flag/status bits */
 #define KB_ASLEEP	(1 << 0)
-	struct clist	gkb_q;		/* input queue */
 	struct selinfo	gkb_rsel;
+	char		gkb_q[KB_QSIZE];		/* input queue */
+	unsigned int	gkb_q_start;
+	unsigned int	gkb_q_length;
 } genkbd_softc_t;
 
 static	SLIST_HEAD(, keyboard_driver) keyboard_drivers =
@@ -521,8 +525,38 @@ kbd_detach(keyboard_t *kbd)
  * driver functions.
  */
 
-#define KB_QSIZE	512
-#define KB_BUFSIZE	64
+static void
+genkbd_putc(genkbd_softc_t *sc, char c)
+{
+	unsigned int p;
+
+	if (sc->gkb_q_length == KB_QSIZE)
+		return;
+
+	p = (sc->gkb_q_start + sc->gkb_q_length) % KB_QSIZE;
+	sc->gkb_q[p] = c;
+	sc->gkb_q_length++;
+}
+
+static size_t
+genkbd_getc(genkbd_softc_t *sc, char *buf, size_t len)
+{
+
+	/* Determine copy size. */
+	if (sc->gkb_q_length == 0)
+		return (0);
+	if (len >= sc->gkb_q_length)
+		len = sc->gkb_q_length;
+	if (len >= KB_QSIZE - sc->gkb_q_start)
+		len = KB_QSIZE - sc->gkb_q_start;
+
+	/* Copy out data and progress offset. */
+	memcpy(buf, sc->gkb_q + sc->gkb_q_start, len);
+	sc->gkb_q_start = (sc->gkb_q_start + len) % KB_QSIZE;
+	sc->gkb_q_length -= len;
+
+	return (len);
+}
 
 static kbd_callback_func_t genkbd_event;
 
@@ -555,10 +589,7 @@ genkbdopen(struct cdev *dev, int mode, int flag, struct thread *td)
 	 * the device may still be missing (!KBD_HAS_DEVICE(kbd)).
 	 */
 
-#if 0
-	bzero(&sc->gkb_q, sizeof(sc->gkb_q));
-#endif
-	clist_alloc_cblocks(&sc->gkb_q, KB_QSIZE, KB_QSIZE/2); /* XXX */
+	sc->gkb_q_length = 0;
 	splx(s);
 
 	return (0);
@@ -582,9 +613,6 @@ genkbdclose(struct cdev *dev, int mode, int flag, struct thread *td)
 		/* XXX: we shall be forgiving and don't report error... */
 	} else {
 		kbd_release(kbd, (void *)sc);
-#if 0
-		clist_free_cblocks(&sc->gkb_q);
-#endif
 	}
 	splx(s);
 	return (0);
@@ -608,7 +636,7 @@ genkbdread(struct cdev *dev, struct uio *uio, int flag)
 		splx(s);
 		return (ENXIO);
 	}
-	while (sc->gkb_q.c_cc == 0) {
+	while (sc->gkb_q_length == 0) {
 		if (flag & O_NONBLOCK) {
 			splx(s);
 			return (EWOULDBLOCK);
@@ -632,7 +660,7 @@ genkbdread(struct cdev *dev, struct uio *uio, int flag)
 	error = 0;
 	while (uio->uio_resid > 0) {
 		len = imin(uio->uio_resid, sizeof(buffer));
-		len = q_to_b(&sc->gkb_q, buffer, len);
+		len = genkbd_getc(sc, buffer, len);
 		if (len <= 0)
 			break;
 		error = uiomove(buffer, len, uio);
@@ -684,7 +712,7 @@ genkbdpoll(struct cdev *dev, int events, struct thread *td)
 	if ((sc == NULL) || (kbd == NULL) || !KBD_IS_VALID(kbd)) {
 		revents =  POLLHUP;	/* the keyboard has gone */
 	} else if (events & (POLLIN | POLLRDNORM)) {
-		if (sc->gkb_q.c_cc > 0)
+		if (sc->gkb_q_length > 0)
 			revents = events & (POLLIN | POLLRDNORM);
 		else
 			selrecord(td, &sc->gkb_rsel);
@@ -738,7 +766,7 @@ genkbd_event(keyboard_t *kbd, int event, void *arg)
 
 		/* store the byte as is for K_RAW and K_CODE modes */
 		if (mode != K_XLATE) {
-			putc(KEYCHAR(c), &sc->gkb_q);
+			genkbd_putc(sc, KEYCHAR(c));
 			continue;
 		}
 
@@ -753,9 +781,9 @@ genkbd_event(keyboard_t *kbd, int event, void *arg)
 				/* ignore them... */
 				continue;
 			case BTAB:	/* a backtab: ESC [ Z */
-				putc(0x1b, &sc->gkb_q);
-				putc('[', &sc->gkb_q);
-				putc('Z', &sc->gkb_q);
+				genkbd_putc(sc, 0x1b);
+				genkbd_putc(sc, '[');
+				genkbd_putc(sc, 'Z');
 				continue;
 			}
 		}
@@ -763,24 +791,24 @@ genkbd_event(keyboard_t *kbd, int event, void *arg)
 		/* normal chars, normal chars with the META, function keys */
 		switch (KEYFLAGS(c)) {
 		case 0:			/* a normal char */
-			putc(KEYCHAR(c), &sc->gkb_q);
+			genkbd_putc(sc, KEYCHAR(c));
 			break;
 		case MKEY:		/* the META flag: prepend ESC */
-			putc(0x1b, &sc->gkb_q);
-			putc(KEYCHAR(c), &sc->gkb_q);
+			genkbd_putc(sc, 0x1b);
+			genkbd_putc(sc, KEYCHAR(c));
 			break;
 		case FKEY | SPCLKEY:	/* a function key, return string */
 			cp = kbdd_get_fkeystr(kbd, KEYCHAR(c), &len);
 			if (cp != NULL) {
 				while (len-- >  0)
-					putc(*cp++, &sc->gkb_q);
+					genkbd_putc(sc, *cp++);
 			}
 			break;
 		}
 	}
 
 	/* wake up sleeping/polling processes */
-	if (sc->gkb_q.c_cc > 0) {
+	if (sc->gkb_q_length > 0) {
 		if (sc->gkb_flags & KB_ASLEEP) {
 			sc->gkb_flags &= ~KB_ASLEEP;
 			wakeup(sc);