ISDN: Add support for none reverse bitstreams to isdnhdc

The original isdnhdlc code was developed for devices which had
reversed bitorder in the byte stream. Adding code to handle normal
bitstreams as well.

Signed-off-by: Karsten Keil <keil@b1-systems.de>

1 files changed, 35 insertions, 35 deletions

diff --git a/drivers/isdn/i4l/isdnhdlc.c b/drivers/isdn/i4l/isdnhdlc.c
index b80e55ab8914..df345ce73f48 100644
--- a/drivers/isdn/i4l/isdnhdlc.c
+++ b/drivers/isdn/i4l/isdnhdlc.c
@@ -2,6 +2,7 @@
  * isdnhdlc.c  --  General purpose ISDN HDLC decoder.
  *
  * Copyright (C)
+ *	2009	Karsten Keil		<keil@b1-systems.de>
  *	2002	Wolfgang Mües		<wolfgang@iksw-muees.de>
  *	2001	Frode Isaksen		<fisaksen@bewan.com>
  *      2001	Kai Germaschewski	<kai.germaschewski@gmx.de>
@@ -25,6 +26,7 @@
 #include <linux/init.h>
 #include <linux/crc-ccitt.h>
 #include <linux/isdn/hdlc.h>
+#include <linux/bitrev.h>
 
 /*-------------------------------------------------------------------*/
 
@@ -48,35 +50,21 @@ enum {
 	HDLC_SENDFLAG_B1A6, HDLC_SENDFLAG_B7, STOPPED
 };
 
-void isdnhdlc_rcv_init(struct isdnhdlc_vars *hdlc, int do_adapt56)
+void isdnhdlc_rcv_init(struct isdnhdlc_vars *hdlc, u32 features)
 {
-	hdlc->bit_shift = 0;
-	hdlc->hdlc_bits1 = 0;
-	hdlc->data_bits = 0;
-	hdlc->ffbit_shift = 0;
-	hdlc->data_received = 0;
+	memset(hdlc, 0, sizeof(struct isdnhdlc_vars));
 	hdlc->state = HDLC_GET_DATA;
-	hdlc->do_adapt56 = do_adapt56;
-	hdlc->dchannel = 0;
-	hdlc->crc = 0;
-	hdlc->cbin = 0;
-	hdlc->shift_reg = 0;
-	hdlc->ffvalue = 0;
-	hdlc->dstpos = 0;
+	if (features & HDLC_56KBIT)
+		hdlc->do_adapt56 = 1;
+	if (features & HDLC_BITREVERSE)
+		hdlc->do_bitreverse = 1;
 }
 EXPORT_SYMBOL(isdnhdlc_out_init);
 
-void isdnhdlc_out_init(struct isdnhdlc_vars *hdlc, int is_d_channel,
-	int do_adapt56)
+void isdnhdlc_out_init(struct isdnhdlc_vars *hdlc, u32 features)
 {
-	hdlc->bit_shift = 0;
-	hdlc->hdlc_bits1 = 0;
-	hdlc->data_bits = 0;
-	hdlc->ffbit_shift = 0;
-	hdlc->data_received = 0;
-	hdlc->do_closing = 0;
-	hdlc->ffvalue = 0;
-	if (is_d_channel) {
+	memset(hdlc, 0, sizeof(struct isdnhdlc_vars));
+	if (features & HDLC_DCHANNEL) {
 		hdlc->dchannel = 1;
 		hdlc->state = HDLC_SEND_FIRST_FLAG;
 	} else {
@@ -85,16 +73,13 @@ void isdnhdlc_out_init(struct isdnhdlc_vars *hdlc, int is_d_channel,
 		hdlc->ffvalue = 0x7e;
 	}
 	hdlc->cbin = 0x7e;
-	hdlc->bit_shift = 0;
-	if (do_adapt56) {
+	if (features & HDLC_56KBIT) {
 		hdlc->do_adapt56 = 1;
-		hdlc->data_bits = 0;
 		hdlc->state = HDLC_SENDFLAG_B0;
-	} else {
-		hdlc->do_adapt56 = 0;
+	} else
 		hdlc->data_bits = 8;
-	}
-	hdlc->shift_reg = 0;
+	if (features & HDLC_BITREVERSE)
+		hdlc->do_bitreverse = 1;
 }
 EXPORT_SYMBOL(isdnhdlc_rcv_init);
 
@@ -188,7 +173,11 @@ int isdnhdlc_decode(struct isdnhdlc_vars *hdlc, const u8 *src, int slen,
 
 	while (slen > 0) {
 		if (hdlc->bit_shift == 0) {
-			hdlc->cbin = *src++;
+			/* the code is for bitreverse streams */
+			if (hdlc->do_bitreverse == 0)
+				hdlc->cbin = bitrev8(*src++);
+			else
+				hdlc->cbin = *src++;
 			slen--;
 			hdlc->bit_shift = 8;
 			if (hdlc->do_adapt56)
@@ -405,12 +394,15 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const u8 *src, u16 slen,
 		case STOPPED:
 			while (dsize--)
 				*dst++ = 0xff;
-
 			return dsize;
 		case HDLC_SEND_FAST_FLAG:
 			hdlc->do_closing = 0;
 			if (slen == 0) {
-				*dst++ = hdlc->ffvalue;
+				/* the code is for bitreverse streams */
+				if (hdlc->do_bitreverse == 0)
+					*dst++ = bitrev8(hdlc->ffvalue);
+				else
+					*dst++ = hdlc->ffvalue;
 				len++;
 				dsize--;
 				break;
@@ -594,7 +586,11 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const u8 *src, u16 slen,
 				hdlc->cbin = 0x7e;
 				hdlc->state = HDLC_SEND_FIRST_FLAG;
 			} else {
-				*dst++ = hdlc->cbin;
+				/* the code is for bitreverse streams */
+				if (hdlc->do_bitreverse == 0)
+					*dst++ = bitrev8(hdlc->cbin);
+				else
+					*dst++ = hdlc->cbin;
 				hdlc->bit_shift = 0;
 				hdlc->data_bits = 0;
 				len++;
@@ -612,7 +608,11 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const u8 *src, u16 slen,
 			}
 		}
 		if (hdlc->data_bits == 8) {
-			*dst++ = hdlc->cbin;
+			/* the code is for bitreverse streams */
+			if (hdlc->do_bitreverse == 0)
+				*dst++ = bitrev8(hdlc->cbin);
+			else
+				*dst++ = hdlc->cbin;
 			hdlc->data_bits = 0;
 			len++;
 			dsize--;