usb_gigaset: code cleanup

Reorganize the code of the Gigaset M10x driver to make it more
readable, less redundant, better aligned to the style of other
parts of the driver, and cause fewer checkpatch.pl complaints.

Impact: code reorganization, no functional change
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 307 insertions, 266 deletions

diff --git a/drivers/isdn/gigaset/asyncdata.c b/drivers/isdn/gigaset/asyncdata.c
index 256fc4809c81..ccb2a7b7c41d 100644
--- a/drivers/isdn/gigaset/asyncdata.c
+++ b/drivers/isdn/gigaset/asyncdata.c
@@ -19,7 +19,7 @@
 
 /* check if byte must be stuffed/escaped
  * I'm not sure which data should be encoded.
- * Therefore I will go the hard way and decode every value
+ * Therefore I will go the hard way and encode every value
  * less than 0x20, the flag sequence and the control escape char.
  */
 static inline int muststuff(unsigned char c)
@@ -35,288 +35,383 @@ static inline int muststuff(unsigned char c)
 
 /* == data input =========================================================== */
 
-/* process a block of received bytes in command mode (modem response)
+/* process a block of received bytes in command mode
+ * (mstate != MS_LOCKED && (inputstate & INS_command))
+ * Append received bytes to the command response buffer and forward them
+ * line by line to the response handler. Exit whenever a mode/state change
+ * might have occurred.
  * Return value:
  *	number of processed bytes
  */
-static inline int cmd_loop(unsigned char c, unsigned char *src, int numbytes,
-			   struct inbuf_t *inbuf)
+static unsigned cmd_loop(unsigned numbytes, struct inbuf_t *inbuf)
 {
+	unsigned char *src = inbuf->data + inbuf->head;
 	struct cardstate *cs = inbuf->cs;
-	unsigned cbytes      = cs->cbytes;
-	int inputstate = inbuf->inputstate;
-	int startbytes = numbytes;
-
-	for (;;) {
-		cs->respdata[cbytes] = c;
-		if (c == 10 || c == 13) {
-			gig_dbg(DEBUG_TRANSCMD, "%s: End of Command (%d Bytes)",
+	unsigned cbytes = cs->cbytes;
+	unsigned procbytes = 0;
+	unsigned char c;
+
+	while (procbytes < numbytes) {
+		c = *src++;
+		procbytes++;
+
+		switch (c) {
+		case '\n':
+			if (cbytes == 0 && cs->respdata[0] == '\r') {
+				/* collapse LF with preceding CR */
+				cs->respdata[0] = 0;
+				break;
+			}
+			/* --v-- fall through --v-- */
+		case '\r':
+			/* end of message line, pass to response handler */
+			gig_dbg(DEBUG_TRANSCMD, "%s: End of Message (%d Bytes)",
 				__func__, cbytes);
+			if (cbytes >= MAX_RESP_SIZE) {
+				dev_warn(cs->dev, "response too large (%d)\n",
+					 cbytes);
+				cbytes = MAX_RESP_SIZE;
+			}
 			cs->cbytes = cbytes;
-			gigaset_handle_modem_response(cs); /* can change
-							      cs->dle */
+			gigaset_handle_modem_response(cs);
 			cbytes = 0;
 
-			if (cs->dle &&
-			    !(inputstate & INS_DLE_command)) {
-				inputstate &= ~INS_command;
-				break;
-			}
-		} else {
-			/* advance in line buffer, checking for overflow */
-			if (cbytes < MAX_RESP_SIZE - 1)
-				cbytes++;
-			else
-				dev_warn(cs->dev, "response too large\n");
-		}
+			/* store EOL byte for CRLF collapsing */
+			cs->respdata[0] = c;
 
-		if (!numbytes)
-			break;
-		c = *src++;
-		--numbytes;
-		if (c == DLE_FLAG &&
-		    (cs->dle || inputstate & INS_DLE_command)) {
-			inputstate |= INS_DLE_char;
-			break;
+			/* cs->dle may have changed */
+			if (cs->dle && !(inbuf->inputstate & INS_DLE_command))
+				inbuf->inputstate &= ~INS_command;
+
+			/* return for reevaluating state */
+			goto exit;
+
+		case DLE_FLAG:
+			if (inbuf->inputstate & INS_DLE_char) {
+				/* quoted DLE: clear quote flag */
+				inbuf->inputstate &= ~INS_DLE_char;
+			} else if (cs->dle ||
+				   (inbuf->inputstate & INS_DLE_command)) {
+				/* DLE escape, pass up for handling */
+				inbuf->inputstate |= INS_DLE_char;
+				goto exit;
+			}
+			/* quoted or not in DLE mode: treat as regular data */
+			/* --v-- fall through --v-- */
+		default:
+			/* append to line buffer if possible */
+			if (cbytes < MAX_RESP_SIZE)
+				cs->respdata[cbytes] = c;
+			cbytes++;
 		}
 	}
-
+exit:
 	cs->cbytes = cbytes;
-	inbuf->inputstate = inputstate;
-
-	return startbytes - numbytes;
+	return procbytes;
 }
 
-/* process a block of received bytes in lock mode (tty i/f)
+/* process a block of received bytes in lock mode
+ * All received bytes are passed unmodified to the tty i/f.
  * Return value:
  *	number of processed bytes
  */
-static inline int lock_loop(unsigned char *src, int numbytes,
-			    struct inbuf_t *inbuf)
+static unsigned lock_loop(unsigned numbytes, struct inbuf_t *inbuf)
 {
-	struct cardstate *cs = inbuf->cs;
-
-	gigaset_dbg_buffer(DEBUG_LOCKCMD, "received response",
-			   numbytes, src);
-	gigaset_if_receive(cs, src, numbytes);
+	unsigned char *src = inbuf->data + inbuf->head;
 
+	gigaset_dbg_buffer(DEBUG_LOCKCMD, "received response", numbytes, src);
+	gigaset_if_receive(inbuf->cs, src, numbytes);
 	return numbytes;
 }
 
+/* set up next receive skb for data mode
+ */
+static void new_rcv_skb(struct bc_state *bcs)
+{
+	struct cardstate *cs = bcs->cs;
+	unsigned short hw_hdr_len = cs->hw_hdr_len;
+
+	if (bcs->ignore) {
+		bcs->skb = NULL;
+		return;
+	}
+
+	bcs->skb = dev_alloc_skb(SBUFSIZE + hw_hdr_len);
+	if (bcs->skb == NULL) {
+		dev_warn(cs->dev, "could not allocate new skb\n");
+		return;
+	}
+	skb_reserve(bcs->skb, hw_hdr_len);
+}
+
 /* process a block of received bytes in HDLC data mode
+ * (mstate != MS_LOCKED && !(inputstate & INS_command) && proto2 == L2_HDLC)
  * Collect HDLC frames, undoing byte stuffing and watching for DLE escapes.
  * When a frame is complete, check the FCS and pass valid frames to the LL.
  * If DLE is encountered, return immediately to let the caller handle it.
  * Return value:
  *	number of processed bytes
- *	numbytes (all bytes processed) on error --FIXME
  */
-static inline int hdlc_loop(unsigned char c, unsigned char *src, int numbytes,
-			    struct inbuf_t *inbuf)
+static unsigned hdlc_loop(unsigned numbytes, struct inbuf_t *inbuf)
 {
 	struct cardstate *cs = inbuf->cs;
-	struct bc_state *bcs = inbuf->bcs;
+	struct bc_state *bcs = cs->bcs;
 	int inputstate = bcs->inputstate;
 	__u16 fcs = bcs->fcs;
 	struct sk_buff *skb = bcs->skb;
-	int startbytes = numbytes;
+	unsigned char *src = inbuf->data + inbuf->head;
+	unsigned procbytes = 0;
+	unsigned char c;
 
-	if (unlikely(inputstate & INS_byte_stuff)) {
+	if (inputstate & INS_byte_stuff) {
+		if (!numbytes)
+			return 0;
 		inputstate &= ~INS_byte_stuff;
 		goto byte_stuff;
 	}
-	for (;;) {
-		if (unlikely(c == PPP_ESCAPE)) {
-			if (unlikely(!numbytes)) {
-				inputstate |= INS_byte_stuff;
+
+	while (procbytes < numbytes) {
+		c = *src++;
+		procbytes++;
+		if (c == DLE_FLAG) {
+			if (inputstate & INS_DLE_char) {
+				/* quoted DLE: clear quote flag */
+				inputstate &= ~INS_DLE_char;
+			} else if (cs->dle || (inputstate & INS_DLE_command)) {
+				/* DLE escape, pass up for handling */
+				inputstate |= INS_DLE_char;
 				break;
 			}
-			c = *src++;
-			--numbytes;
-			if (unlikely(c == DLE_FLAG &&
-				     (cs->dle ||
-				      inbuf->inputstate & INS_DLE_command))) {
-				inbuf->inputstate |= INS_DLE_char;
+		}
+
+		if (c == PPP_ESCAPE) {
+			/* byte stuffing indicator: pull in next byte */
+			if (procbytes >= numbytes) {
+				/* end of buffer, save for later processing */
 				inputstate |= INS_byte_stuff;
 				break;
 			}
 byte_stuff:
+			c = *src++;
+			procbytes++;
+			if (c == DLE_FLAG) {
+				if (inputstate & INS_DLE_char) {
+					/* quoted DLE: clear quote flag */
+					inputstate &= ~INS_DLE_char;
+				} else if (cs->dle ||
+					   (inputstate & INS_DLE_command)) {
+					/* DLE escape, pass up for handling */
+					inputstate |=
+						INS_DLE_char | INS_byte_stuff;
+					break;
+				}
+			}
 			c ^= PPP_TRANS;
-			if (unlikely(!muststuff(c)))
-				gig_dbg(DEBUG_HDLC, "byte stuffed: 0x%02x", c);
-		} else if (unlikely(c == PPP_FLAG)) {
-			if (unlikely(inputstate & INS_skip_frame)) {
 #ifdef CONFIG_GIGASET_DEBUG
-				if (!(inputstate & INS_have_data)) { /* 7E 7E */
-					++bcs->emptycount;
-				} else
-					gig_dbg(DEBUG_HDLC,
-					    "7e----------------------------");
-#endif
-
-				/* end of frame */
-				gigaset_isdn_rcv_err(bcs);
-				dev_kfree_skb_any(skb);
-			} else if (!(inputstate & INS_have_data)) { /* 7E 7E */
-#ifdef CONFIG_GIGASET_DEBUG
-				++bcs->emptycount;
+			if (!muststuff(c))
+				gig_dbg(DEBUG_HDLC, "byte stuffed: 0x%02x", c);
 #endif
-				break;
-			} else {
+		} else if (c == PPP_FLAG) {
+			/* end of frame: process content if any */
+			if (inputstate & INS_have_data) {
 				gig_dbg(DEBUG_HDLC,
 					"7e----------------------------");
 
-				/* end of frame */
-				if (unlikely(fcs != PPP_GOODFCS)) {
+				/* check and pass received frame */
+				if (!skb) {
+					/* skipped frame */
+					gigaset_isdn_rcv_err(bcs);
+				} else if (skb->len < 2) {
+					/* frame too short for FCS */
+					dev_warn(cs->dev,
+						 "short frame (%d)\n",
+						 skb->len);
+					gigaset_isdn_rcv_err(bcs);
+					dev_kfree_skb_any(skb);
+				} else if (fcs != PPP_GOODFCS) {
+					/* frame check error */
 					dev_err(cs->dev,
 				"Checksum failed, %u bytes corrupted!\n",
 						skb->len);
 					gigaset_isdn_rcv_err(bcs);
 					dev_kfree_skb_any(skb);
-				} else if (likely(skb->len > 2)) {
+				} else {
+					/* good frame */
 					__skb_trim(skb, skb->len - 2);
 					gigaset_skb_rcvd(bcs, skb);
-				} else {
-					if (skb->len) {
-						dev_err(cs->dev,
-					"invalid packet size (%d)\n", skb->len);
-						gigaset_isdn_rcv_err(bcs);
-					}
-					dev_kfree_skb_any(skb);
 				}
-			}
 
-			fcs = PPP_INITFCS;
-			inputstate &= ~(INS_have_data | INS_skip_frame);
-			if (unlikely(bcs->ignore)) {
-				inputstate |= INS_skip_frame;
-				skb = NULL;
+				/* prepare reception of next frame */
+				inputstate &= ~INS_have_data;
+				new_rcv_skb(bcs);
+				skb = bcs->skb;
 			} else {
-				skb = dev_alloc_skb(SBUFSIZE + cs->hw_hdr_len);
-				if (skb != NULL) {
-					skb_reserve(skb, cs->hw_hdr_len);
-				} else {
-					dev_warn(cs->dev,
-						"could not allocate new skb\n");
-					inputstate |= INS_skip_frame;
+				/* empty frame (7E 7E) */
+#ifdef CONFIG_GIGASET_DEBUG
+				++bcs->emptycount;
+#endif
+				if (!skb) {
+					/* skipped (?) */
+					gigaset_isdn_rcv_err(bcs);
+					new_rcv_skb(bcs);
+					skb = bcs->skb;
 				}
 			}
 
-			break;
-		} else if (unlikely(muststuff(c))) {
+			fcs = PPP_INITFCS;
+			continue;
+#ifdef CONFIG_GIGASET_DEBUG
+		} else if (muststuff(c)) {
 			/* Should not happen. Possible after ZDLE=1<CR><LF>. */
 			gig_dbg(DEBUG_HDLC, "not byte stuffed: 0x%02x", c);
+#endif
 		}
 
-		/* add character */
-
+		/* regular data byte, append to skb */
 #ifdef CONFIG_GIGASET_DEBUG
-		if (unlikely(!(inputstate & INS_have_data))) {
+		if (!(inputstate & INS_have_data)) {
 			gig_dbg(DEBUG_HDLC, "7e (%d x) ================",
 				bcs->emptycount);
 			bcs->emptycount = 0;
 		}
 #endif
-
 		inputstate |= INS_have_data;
-
-		if (likely(!(inputstate & INS_skip_frame))) {
-			if (unlikely(skb->len == SBUFSIZE)) {
+		if (skb) {
+			if (skb->len == SBUFSIZE) {
 				dev_warn(cs->dev, "received packet too long\n");
 				dev_kfree_skb_any(skb);
-				skb = NULL;
-				inputstate |= INS_skip_frame;
-				break;
+				/* skip remainder of packet */
+				bcs->skb = skb = NULL;
+			} else {
+				*__skb_put(skb, 1) = c;
+				fcs = crc_ccitt_byte(fcs, c);
 			}
-			*__skb_put(skb, 1) = c;
-			fcs = crc_ccitt_byte(fcs, c);
-		}
-
-		if (unlikely(!numbytes))
-			break;
-		c = *src++;
-		--numbytes;
-		if (unlikely(c == DLE_FLAG &&
-			     (cs->dle ||
-			      inbuf->inputstate & INS_DLE_command))) {
-			inbuf->inputstate |= INS_DLE_char;
-			break;
 		}
 	}
+
 	bcs->inputstate = inputstate;
 	bcs->fcs = fcs;
-	bcs->skb = skb;
-	return startbytes - numbytes;
+	return procbytes;
 }
 
 /* process a block of received bytes in transparent data mode
+ * (mstate != MS_LOCKED && !(inputstate & INS_command) && proto2 != L2_HDLC)
  * Invert bytes, undoing byte stuffing and watching for DLE escapes.
  * If DLE is encountered, return immediately to let the caller handle it.
  * Return value:
  *	number of processed bytes
- *	numbytes (all bytes processed) on error --FIXME
  */
-static inline int iraw_loop(unsigned char c, unsigned char *src, int numbytes,
-			    struct inbuf_t *inbuf)
+static unsigned iraw_loop(unsigned numbytes, struct inbuf_t *inbuf)
 {
 	struct cardstate *cs = inbuf->cs;
-	struct bc_state *bcs = inbuf->bcs;
+	struct bc_state *bcs = cs->bcs;
 	int inputstate = bcs->inputstate;
 	struct sk_buff *skb = bcs->skb;
-	int startbytes = numbytes;
+	unsigned char *src = inbuf->data + inbuf->head;
+	unsigned procbytes = 0;
+	unsigned char c;
 
-	for (;;) {
-		/* add character */
-		inputstate |= INS_have_data;
+	if (!skb) {
+		/* skip this block */
+		new_rcv_skb(bcs);
+		return numbytes;
+	}
 
-		if (likely(!(inputstate & INS_skip_frame))) {
-			if (unlikely(skb->len == SBUFSIZE)) {
-				//FIXME just pass skb up and allocate a new one
-				dev_warn(cs->dev, "received packet too long\n");
-				dev_kfree_skb_any(skb);
-				skb = NULL;
-				inputstate |= INS_skip_frame;
+	while (procbytes < numbytes && skb->len < SBUFSIZE) {
+		c = *src++;
+		procbytes++;
+
+		if (c == DLE_FLAG) {
+			if (inputstate & INS_DLE_char) {
+				/* quoted DLE: clear quote flag */
+				inputstate &= ~INS_DLE_char;
+			} else if (cs->dle || (inputstate & INS_DLE_command)) {
+				/* DLE escape, pass up for handling */
+				inputstate |= INS_DLE_char;
 				break;
 			}
-			*__skb_put(skb, 1) = bitrev8(c);
 		}
 
-		if (unlikely(!numbytes))
-			break;
-		c = *src++;
-		--numbytes;
-		if (unlikely(c == DLE_FLAG &&
-			     (cs->dle ||
-			      inbuf->inputstate & INS_DLE_command))) {
-			inbuf->inputstate |= INS_DLE_char;
-			break;
-		}
+		/* regular data byte: append to current skb */
+		inputstate |= INS_have_data;
+		*__skb_put(skb, 1) = bitrev8(c);
 	}
 
 	/* pass data up */
-	if (likely(inputstate & INS_have_data)) {
-		if (likely(!(inputstate & INS_skip_frame))) {
-			gigaset_skb_rcvd(bcs, skb);
-		}
-		inputstate &= ~(INS_have_data | INS_skip_frame);
-		if (unlikely(bcs->ignore)) {
-			inputstate |= INS_skip_frame;
-			skb = NULL;
-		} else {
-			skb = dev_alloc_skb(SBUFSIZE + cs->hw_hdr_len);
-			if (skb != NULL) {
-				skb_reserve(skb, cs->hw_hdr_len);
-			} else {
-				dev_warn(cs->dev,
-					 "could not allocate new skb\n");
-				inputstate |= INS_skip_frame;
+	if (inputstate & INS_have_data) {
+		gigaset_skb_rcvd(bcs, skb);
+		inputstate &= ~INS_have_data;
+		new_rcv_skb(bcs);
+	}
+
+	bcs->inputstate = inputstate;
+	return procbytes;
+}
+
+/* process DLE escapes
+ * Called whenever a DLE sequence might be encountered in the input stream.
+ * Either processes the entire DLE sequence or, if that isn't possible,
+ * notes the fact that an initial DLE has been received in the INS_DLE_char
+ * inputstate flag and resumes processing of the sequence on the next call.
+ */
+static void handle_dle(struct inbuf_t *inbuf)
+{
+	struct cardstate *cs = inbuf->cs;
+
+	if (cs->mstate == MS_LOCKED)
+		return;		/* no DLE processing in lock mode */
+
+	if (!(inbuf->inputstate & INS_DLE_char)) {
+		/* no DLE pending */
+		if (inbuf->data[inbuf->head] == DLE_FLAG &&
+		    (cs->dle || inbuf->inputstate & INS_DLE_command)) {
+			/* start of DLE sequence */
+			inbuf->head++;
+			if (inbuf->head == inbuf->tail ||
+			    inbuf->head == RBUFSIZE) {
+				/* end of buffer, save for later processing */
+				inbuf->inputstate |= INS_DLE_char;
+				return;
 			}
+		} else {
+			/* regular data byte */
+			return;
 		}
 	}
 
-	bcs->inputstate = inputstate;
-	bcs->skb = skb;
-	return startbytes - numbytes;
+	/* consume pending DLE */
+	inbuf->inputstate &= ~INS_DLE_char;
+
+	switch (inbuf->data[inbuf->head]) {
+	case 'X':	/* begin of event message */
+		if (inbuf->inputstate & INS_command)
+			dev_notice(cs->dev,
+				   "received <DLE>X in command mode\n");
+		inbuf->inputstate |= INS_command | INS_DLE_command;
+		inbuf->head++;	/* byte consumed */
+		break;
+	case '.':	/* end of event message */
+		if (!(inbuf->inputstate & INS_DLE_command))
+			dev_notice(cs->dev,
+				   "received <DLE>. without <DLE>X\n");
+		inbuf->inputstate &= ~INS_DLE_command;
+		/* return to data mode if in DLE mode */
+		if (cs->dle)
+			inbuf->inputstate &= ~INS_command;
+		inbuf->head++;	/* byte consumed */
+		break;
+	case DLE_FLAG:	/* DLE in data stream */
+		/* mark as quoted */
+		inbuf->inputstate |= INS_DLE_char;
+		if (!(cs->dle || inbuf->inputstate & INS_DLE_command))
+			dev_notice(cs->dev,
+				   "received <DLE><DLE> not in DLE mode\n");
+		break;	/* quoted byte left in buffer */
+	default:
+		dev_notice(cs->dev, "received <DLE><%02x>\n",
+			   inbuf->data[inbuf->head]);
+		/* quoted byte left in buffer */
+	}
 }
 
 /**
@@ -330,94 +425,39 @@ static inline int iraw_loop(unsigned char c, unsigned char *src, int numbytes,
  */
 void gigaset_m10x_input(struct inbuf_t *inbuf)
 {
-	struct cardstate *cs;
-	unsigned tail, head, numbytes;
-	unsigned char *src, c;
-	int procbytes;
-
-	head = inbuf->head;
-	tail = inbuf->tail;
-	gig_dbg(DEBUG_INTR, "buffer state: %u -> %u", head, tail);
-
-	if (head != tail) {
-		cs = inbuf->cs;
-		src = inbuf->data + head;
-		numbytes = (head > tail ? RBUFSIZE : tail) - head;
-		gig_dbg(DEBUG_INTR, "processing %u bytes", numbytes);
+	struct cardstate *cs = inbuf->cs;
+	unsigned numbytes, procbytes;
 
-		while (numbytes) {
-			if (cs->mstate == MS_LOCKED) {
-				procbytes = lock_loop(src, numbytes, inbuf);
-				src += procbytes;
-				numbytes -= procbytes;
-			} else {
-				c = *src++;
-				--numbytes;
-				if (c == DLE_FLAG && (cs->dle ||
-				    inbuf->inputstate & INS_DLE_command)) {
-					if (!(inbuf->inputstate & INS_DLE_char)) {
-						inbuf->inputstate |= INS_DLE_char;
-						goto nextbyte;
-					}
-					/* <DLE> <DLE> => <DLE> in data stream */
-					inbuf->inputstate &= ~INS_DLE_char;
-				}
+	gig_dbg(DEBUG_INTR, "buffer state: %u -> %u", inbuf->head, inbuf->tail);
 
-				if (!(inbuf->inputstate & INS_DLE_char)) {
-
-					/* FIXME use function pointers?  */
-					if (inbuf->inputstate & INS_command)
-						procbytes = cmd_loop(c, src, numbytes, inbuf);
-					else if (inbuf->bcs->proto2 == L2_HDLC)
-						procbytes = hdlc_loop(c, src, numbytes, inbuf);
-					else
-						procbytes = iraw_loop(c, src, numbytes, inbuf);
-
-					src += procbytes;
-					numbytes -= procbytes;
-				} else {  /* DLE char */
-					inbuf->inputstate &= ~INS_DLE_char;
-					switch (c) {
-					case 'X': /*begin of command*/
-						if (inbuf->inputstate & INS_command)
-							dev_warn(cs->dev,
-					"received <DLE> 'X' in command mode\n");
-						inbuf->inputstate |=
-							INS_command | INS_DLE_command;
-						break;
-					case '.': /*end of command*/
-						if (!(inbuf->inputstate & INS_command))
-							dev_warn(cs->dev,
-					"received <DLE> '.' in hdlc mode\n");
-						inbuf->inputstate &= cs->dle ?
-							~(INS_DLE_command|INS_command)
-							: ~INS_DLE_command;
-						break;
-					//case DLE_FLAG: /*DLE_FLAG in data stream*/ /* schon oben behandelt! */
-					default:
-						dev_err(cs->dev,
-						      "received 0x10 0x%02x!\n",
-							(int) c);
-						/* FIXME: reset driver?? */
-					}
-				}
-			}
-nextbyte:
-			if (!numbytes) {
-				/* end of buffer, check for wrap */
-				if (head > tail) {
-					head = 0;
-					src = inbuf->data;
-					numbytes = tail;
-				} else {
-					head = tail;
-					break;
-				}
-			}
-		}
+	while (inbuf->head != inbuf->tail) {
+		/* check for DLE escape */
+		handle_dle(inbuf);
 
-		gig_dbg(DEBUG_INTR, "setting head to %u", head);
-		inbuf->head = head;
+		/* process a contiguous block of bytes */
+		numbytes = (inbuf->head > inbuf->tail ?
+			    RBUFSIZE : inbuf->tail) - inbuf->head;
+		gig_dbg(DEBUG_INTR, "processing %u bytes", numbytes);
+		/*
+		 * numbytes may be 0 if handle_dle() ate the last byte.
+		 * This does no harm, *_loop() will just return 0 immediately.
+		 */
+
+		if (cs->mstate == MS_LOCKED)
+			procbytes = lock_loop(numbytes, inbuf);
+		else if (inbuf->inputstate & INS_command)
+			procbytes = cmd_loop(numbytes, inbuf);
+		else if (cs->bcs->proto2 == L2_HDLC)
+			procbytes = hdlc_loop(numbytes, inbuf);
+		else
+			procbytes = iraw_loop(numbytes, inbuf);
+		inbuf->head += procbytes;
+
+		/* check for buffer wraparound */
+		if (inbuf->head >= RBUFSIZE)
+			inbuf->head = 0;
+
+		gig_dbg(DEBUG_INTR, "head set to %u", inbuf->head);
 	}
 }
 EXPORT_SYMBOL_GPL(gigaset_m10x_input);
@@ -563,6 +603,7 @@ static struct sk_buff *iraw_encode(struct sk_buff *skb)
  */
 int gigaset_m10x_send_skb(struct bc_state *bcs, struct sk_buff *skb)
 {
+	struct cardstate *cs = bcs->cs;
 	unsigned len = skb->len;
 	unsigned long flags;
 
@@ -571,16 +612,16 @@ int gigaset_m10x_send_skb(struct bc_state *bcs, struct sk_buff *skb)
 	else
 		skb = iraw_encode(skb);
 	if (!skb) {
-		dev_err(bcs->cs->dev,
+		dev_err(cs->dev,
 			"unable to allocate memory for encoding!\n");
 		return -ENOMEM;
 	}
 
 	skb_queue_tail(&bcs->squeue, skb);
-	spin_lock_irqsave(&bcs->cs->lock, flags);
-	if (bcs->cs->connected)
-		tasklet_schedule(&bcs->cs->write_tasklet);
-	spin_unlock_irqrestore(&bcs->cs->lock, flags);
+	spin_lock_irqsave(&cs->lock, flags);
+	if (cs->connected)
+		tasklet_schedule(&cs->write_tasklet);
+	spin_unlock_irqrestore(&cs->lock, flags);
 
 	return len;	/* ok so far */
 }