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-rw-r--r--drivers/isdn/i4l/Kconfig11
-rw-r--r--drivers/isdn/i4l/Makefile1
-rw-r--r--drivers/isdn/i4l/isdnhdlc.c603
3 files changed, 615 insertions, 0 deletions
diff --git a/drivers/isdn/i4l/Kconfig b/drivers/isdn/i4l/Kconfig
index ed3510f273d8..dd744ffd240b 100644
--- a/drivers/isdn/i4l/Kconfig
+++ b/drivers/isdn/i4l/Kconfig
@@ -2,6 +2,8 @@
# Old ISDN4Linux config
#
+if ISDN_I4L
+
config ISDN_PPP
bool "Support synchronous PPP"
depends on INET
@@ -135,3 +137,12 @@ source "drivers/isdn/act2000/Kconfig"
source "drivers/isdn/hysdn/Kconfig"
endmenu
+# end ISDN_I4L
+endif
+
+config ISDN_HDLC
+ tristate
+ depends on HISAX_ST5481
+ select CRC_CCITT
+ select BITREVERSE
+
diff --git a/drivers/isdn/i4l/Makefile b/drivers/isdn/i4l/Makefile
index 49a06c0005dd..cb9d3bb9fae0 100644
--- a/drivers/isdn/i4l/Makefile
+++ b/drivers/isdn/i4l/Makefile
@@ -4,6 +4,7 @@
obj-$(CONFIG_ISDN_I4L) += isdn.o
obj-$(CONFIG_ISDN_PPP_BSDCOMP) += isdn_bsdcomp.o
+obj-$(CONFIG_ISDN_HDLC) += isdnhdlc.o
# Multipart objects.
diff --git a/drivers/isdn/i4l/isdnhdlc.c b/drivers/isdn/i4l/isdnhdlc.c
new file mode 100644
index 000000000000..44ec7418496b
--- /dev/null
+++ b/drivers/isdn/i4l/isdnhdlc.c
@@ -0,0 +1,603 @@
+/*
+ * isdnhdlc.c -- General purpose ISDN HDLC decoder.
+ *
+ *Copyright (C) 2002 Wolfgang Mües <wolfgang@iksw-muees.de>
+ * 2001 Frode Isaksen <fisaksen@bewan.com>
+ * 2001 Kai Germaschewski <kai.germaschewski@gmx.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/crc-ccitt.h>
+#include <linux/isdn/hdlc.h>
+
+/*-------------------------------------------------------------------*/
+
+MODULE_AUTHOR("Wolfgang Mües <wolfgang@iksw-muees.de>, "
+ "Frode Isaksen <fisaksen@bewan.com>, "
+ "Kai Germaschewski <kai.germaschewski@gmx.de>");
+MODULE_DESCRIPTION("General purpose ISDN HDLC decoder");
+MODULE_LICENSE("GPL");
+
+/*-------------------------------------------------------------------*/
+
+enum {
+ HDLC_FAST_IDLE,HDLC_GET_FLAG_B0,HDLC_GETFLAG_B1A6,HDLC_GETFLAG_B7,
+ HDLC_GET_DATA,HDLC_FAST_FLAG
+};
+
+enum {
+ HDLC_SEND_DATA,HDLC_SEND_CRC1,HDLC_SEND_FAST_FLAG,
+ HDLC_SEND_FIRST_FLAG,HDLC_SEND_CRC2,HDLC_SEND_CLOSING_FLAG,
+ HDLC_SEND_IDLE1,HDLC_SEND_FAST_IDLE,HDLC_SENDFLAG_B0,
+ HDLC_SENDFLAG_B1A6,HDLC_SENDFLAG_B7,STOPPED
+};
+
+void isdnhdlc_rcv_init (struct isdnhdlc_vars *hdlc, int do_adapt56)
+{
+ hdlc->bit_shift = 0;
+ hdlc->hdlc_bits1 = 0;
+ hdlc->data_bits = 0;
+ hdlc->ffbit_shift = 0;
+ hdlc->data_received = 0;
+ 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;
+}
+
+void isdnhdlc_out_init (struct isdnhdlc_vars *hdlc, int is_d_channel, int do_adapt56)
+{
+ 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) {
+ hdlc->dchannel = 1;
+ hdlc->state = HDLC_SEND_FIRST_FLAG;
+ } else {
+ hdlc->dchannel = 0;
+ hdlc->state = HDLC_SEND_FAST_FLAG;
+ hdlc->ffvalue = 0x7e;
+ }
+ hdlc->cbin = 0x7e;
+ hdlc->bit_shift = 0;
+ if(do_adapt56){
+ hdlc->do_adapt56 = 1;
+ hdlc->data_bits = 0;
+ hdlc->state = HDLC_SENDFLAG_B0;
+ } else {
+ hdlc->do_adapt56 = 0;
+ hdlc->data_bits = 8;
+ }
+ hdlc->shift_reg = 0;
+}
+
+/*
+ isdnhdlc_decode - decodes HDLC frames from a transparent bit stream.
+
+ The source buffer is scanned for valid HDLC frames looking for
+ flags (01111110) to indicate the start of a frame. If the start of
+ the frame is found, the bit stuffing is removed (0 after 5 1's).
+ When a new flag is found, the complete frame has been received
+ and the CRC is checked.
+ If a valid frame is found, the function returns the frame length
+ excluding the CRC with the bit HDLC_END_OF_FRAME set.
+ If the beginning of a valid frame is found, the function returns
+ the length.
+ If a framing error is found (too many 1s and not a flag) the function
+ returns the length with the bit HDLC_FRAMING_ERROR set.
+ If a CRC error is found the function returns the length with the
+ bit HDLC_CRC_ERROR set.
+ If the frame length exceeds the destination buffer size, the function
+ returns the length with the bit HDLC_LENGTH_ERROR set.
+
+ src - source buffer
+ slen - source buffer length
+ count - number of bytes removed (decoded) from the source buffer
+ dst _ destination buffer
+ dsize - destination buffer size
+ returns - number of decoded bytes in the destination buffer and status
+ flag.
+ */
+int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src,
+ int slen, int *count, unsigned char *dst, int dsize)
+{
+ int status=0;
+
+ static const unsigned char fast_flag[]={
+ 0x00,0x00,0x00,0x20,0x30,0x38,0x3c,0x3e,0x3f
+ };
+
+ static const unsigned char fast_flag_value[]={
+ 0x00,0x7e,0xfc,0xf9,0xf3,0xe7,0xcf,0x9f,0x3f
+ };
+
+ static const unsigned char fast_abort[]={
+ 0x00,0x00,0x80,0xc0,0xe0,0xf0,0xf8,0xfc,0xfe,0xff
+ };
+
+ *count = slen;
+
+ while(slen > 0){
+ if(hdlc->bit_shift==0){
+ hdlc->cbin = *src++;
+ slen--;
+ hdlc->bit_shift = 8;
+ if(hdlc->do_adapt56){
+ hdlc->bit_shift --;
+ }
+ }
+
+ switch(hdlc->state){
+ case STOPPED:
+ return 0;
+ case HDLC_FAST_IDLE:
+ if(hdlc->cbin == 0xff){
+ hdlc->bit_shift = 0;
+ break;
+ }
+ hdlc->state = HDLC_GET_FLAG_B0;
+ hdlc->hdlc_bits1 = 0;
+ hdlc->bit_shift = 8;
+ break;
+ case HDLC_GET_FLAG_B0:
+ if(!(hdlc->cbin & 0x80)) {
+ hdlc->state = HDLC_GETFLAG_B1A6;
+ hdlc->hdlc_bits1 = 0;
+ } else {
+ if(!hdlc->do_adapt56){
+ if(++hdlc->hdlc_bits1 >=8 ) if(hdlc->bit_shift==1)
+ hdlc->state = HDLC_FAST_IDLE;
+ }
+ }
+ hdlc->cbin<<=1;
+ hdlc->bit_shift --;
+ break;
+ case HDLC_GETFLAG_B1A6:
+ if(hdlc->cbin & 0x80){
+ hdlc->hdlc_bits1++;
+ if(hdlc->hdlc_bits1==6){
+ hdlc->state = HDLC_GETFLAG_B7;
+ }
+ } else {
+ hdlc->hdlc_bits1 = 0;
+ }
+ hdlc->cbin<<=1;
+ hdlc->bit_shift --;
+ break;
+ case HDLC_GETFLAG_B7:
+ if(hdlc->cbin & 0x80) {
+ hdlc->state = HDLC_GET_FLAG_B0;
+ } else {
+ hdlc->state = HDLC_GET_DATA;
+ hdlc->crc = 0xffff;
+ hdlc->shift_reg = 0;
+ hdlc->hdlc_bits1 = 0;
+ hdlc->data_bits = 0;
+ hdlc->data_received = 0;
+ }
+ hdlc->cbin<<=1;
+ hdlc->bit_shift --;
+ break;
+ case HDLC_GET_DATA:
+ if(hdlc->cbin & 0x80){
+ hdlc->hdlc_bits1++;
+ switch(hdlc->hdlc_bits1){
+ case 6:
+ break;
+ case 7:
+ if(hdlc->data_received) {
+ // bad frame
+ status = -HDLC_FRAMING_ERROR;
+ }
+ if(!hdlc->do_adapt56){
+ if(hdlc->cbin==fast_abort[hdlc->bit_shift+1]){
+ hdlc->state = HDLC_FAST_IDLE;
+ hdlc->bit_shift=1;
+ break;
+ }
+ } else {
+ hdlc->state = HDLC_GET_FLAG_B0;
+ }
+ break;
+ default:
+ hdlc->shift_reg>>=1;
+ hdlc->shift_reg |= 0x80;
+ hdlc->data_bits++;
+ break;
+ }
+ } else {
+ switch(hdlc->hdlc_bits1){
+ case 5:
+ break;
+ case 6:
+ if(hdlc->data_received){
+ if (hdlc->dstpos < 2) {
+ status = -HDLC_FRAMING_ERROR;
+ } else if (hdlc->crc != 0xf0b8){
+ // crc error
+ status = -HDLC_CRC_ERROR;
+ } else {
+ // remove CRC
+ hdlc->dstpos -= 2;
+ // good frame
+ status = hdlc->dstpos;
+ }
+ }
+ hdlc->crc = 0xffff;
+ hdlc->shift_reg = 0;
+ hdlc->data_bits = 0;
+ if(!hdlc->do_adapt56){
+ if(hdlc->cbin==fast_flag[hdlc->bit_shift]){
+ hdlc->ffvalue = fast_flag_value[hdlc->bit_shift];
+ hdlc->state = HDLC_FAST_FLAG;
+ hdlc->ffbit_shift = hdlc->bit_shift;
+ hdlc->bit_shift = 1;
+ } else {
+ hdlc->state = HDLC_GET_DATA;
+ hdlc->data_received = 0;
+ }
+ } else {
+ hdlc->state = HDLC_GET_DATA;
+ hdlc->data_received = 0;
+ }
+ break;
+ default:
+ hdlc->shift_reg>>=1;
+ hdlc->data_bits++;
+ break;
+ }
+ hdlc->hdlc_bits1 = 0;
+ }
+ if (status) {
+ hdlc->dstpos = 0;
+ *count -= slen;
+ hdlc->cbin <<= 1;
+ hdlc->bit_shift--;
+ return status;
+ }
+ if(hdlc->data_bits==8){
+ hdlc->data_bits = 0;
+ hdlc->data_received = 1;
+ hdlc->crc = crc_ccitt_byte(hdlc->crc, hdlc->shift_reg);
+
+ // good byte received
+ if (hdlc->dstpos < dsize) {
+ dst[hdlc->dstpos++] = hdlc->shift_reg;
+ } else {
+ // frame too long
+ status = -HDLC_LENGTH_ERROR;
+ hdlc->dstpos = 0;
+ }
+ }
+ hdlc->cbin <<= 1;
+ hdlc->bit_shift--;
+ break;
+ case HDLC_FAST_FLAG:
+ if(hdlc->cbin==hdlc->ffvalue){
+ hdlc->bit_shift = 0;
+ break;
+ } else {
+ if(hdlc->cbin == 0xff){
+ hdlc->state = HDLC_FAST_IDLE;
+ hdlc->bit_shift=0;
+ } else if(hdlc->ffbit_shift==8){
+ hdlc->state = HDLC_GETFLAG_B7;
+ break;
+ } else {
+ hdlc->shift_reg = fast_abort[hdlc->ffbit_shift-1];
+ hdlc->hdlc_bits1 = hdlc->ffbit_shift-2;
+ if(hdlc->hdlc_bits1<0)hdlc->hdlc_bits1 = 0;
+ hdlc->data_bits = hdlc->ffbit_shift-1;
+ hdlc->state = HDLC_GET_DATA;
+ hdlc->data_received = 0;
+ }
+ }
+ break;
+ default:
+ break;
+ }
+ }
+ *count -= slen;
+ return 0;
+}
+
+/*
+ isdnhdlc_encode - encodes HDLC frames to a transparent bit stream.
+
+ The bit stream starts with a beginning flag (01111110). After
+ that each byte is added to the bit stream with bit stuffing added
+ (0 after 5 1's).
+ When the last byte has been removed from the source buffer, the
+ CRC (2 bytes is added) and the frame terminates with the ending flag.
+ For the dchannel, the idle character (all 1's) is also added at the end.
+ If this function is called with empty source buffer (slen=0), flags or
+ idle character will be generated.
+
+ src - source buffer
+ slen - source buffer length
+ count - number of bytes removed (encoded) from source buffer
+ dst _ destination buffer
+ dsize - destination buffer size
+ returns - number of encoded bytes in the destination buffer
+*/
+int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const unsigned char *src,
+ unsigned short slen, int *count,
+ unsigned char *dst, int dsize)
+{
+ static const unsigned char xfast_flag_value[] = {
+ 0x7e,0x3f,0x9f,0xcf,0xe7,0xf3,0xf9,0xfc,0x7e
+ };
+
+ int len = 0;
+
+ *count = slen;
+
+ while (dsize > 0) {
+ if(hdlc->bit_shift==0){
+ if(slen && !hdlc->do_closing){
+ hdlc->shift_reg = *src++;
+ slen--;
+ if (slen == 0)
+ hdlc->do_closing = 1; /* closing sequence, CRC + flag(s) */
+ hdlc->bit_shift = 8;
+ } else {
+ if(hdlc->state == HDLC_SEND_DATA){
+ if(hdlc->data_received){
+ hdlc->state = HDLC_SEND_CRC1;
+ hdlc->crc ^= 0xffff;
+ hdlc->bit_shift = 8;
+ hdlc->shift_reg = hdlc->crc & 0xff;
+ } else if(!hdlc->do_adapt56){
+ hdlc->state = HDLC_SEND_FAST_FLAG;
+ } else {
+ hdlc->state = HDLC_SENDFLAG_B0;
+ }
+ }
+
+ }
+ }
+
+ switch(hdlc->state){
+ case STOPPED:
+ while (dsize--)
+ *dst++ = 0xff;
+
+ return dsize;
+ case HDLC_SEND_FAST_FLAG:
+ hdlc->do_closing = 0;
+ if(slen == 0){
+ *dst++ = hdlc->ffvalue;
+ len++;
+ dsize--;
+ break;
+ }
+ if(hdlc->bit_shift==8){
+ hdlc->cbin = hdlc->ffvalue>>(8-hdlc->data_bits);
+ hdlc->state = HDLC_SEND_DATA;
+ hdlc->crc = 0xffff;
+ hdlc->hdlc_bits1 = 0;
+ hdlc->data_received = 1;
+ }
+ break;
+ case HDLC_SENDFLAG_B0:
+ hdlc->do_closing = 0;
+ hdlc->cbin <<= 1;
+ hdlc->data_bits++;
+ hdlc->hdlc_bits1 = 0;
+ hdlc->state = HDLC_SENDFLAG_B1A6;
+ break;
+ case HDLC_SENDFLAG_B1A6:
+ hdlc->cbin <<= 1;
+ hdlc->data_bits++;
+ hdlc->cbin++;
+ if(++hdlc->hdlc_bits1 == 6)
+ hdlc->state = HDLC_SENDFLAG_B7;
+ break;
+ case HDLC_SENDFLAG_B7:
+ hdlc->cbin <<= 1;
+ hdlc->data_bits++;
+ if(slen == 0){
+ hdlc->state = HDLC_SENDFLAG_B0;
+ break;
+ }
+ if(hdlc->bit_shift==8){
+ hdlc->state = HDLC_SEND_DATA;
+ hdlc->crc = 0xffff;
+ hdlc->hdlc_bits1 = 0;
+ hdlc->data_received = 1;
+ }
+ break;
+ case HDLC_SEND_FIRST_FLAG:
+ hdlc->data_received = 1;
+ if(hdlc->data_bits==8){
+ hdlc->state = HDLC_SEND_DATA;
+ hdlc->crc = 0xffff;
+ hdlc->hdlc_bits1 = 0;
+ break;
+ }
+ hdlc->cbin <<= 1;
+ hdlc->data_bits++;
+ if(hdlc->shift_reg & 0x01)
+ hdlc->cbin++;
+ hdlc->shift_reg >>= 1;
+ hdlc->bit_shift--;
+ if(hdlc->bit_shift==0){
+ hdlc->state = HDLC_SEND_DATA;
+ hdlc->crc = 0xffff;
+ hdlc->hdlc_bits1 = 0;
+ }
+ break;
+ case HDLC_SEND_DATA:
+ hdlc->cbin <<= 1;
+ hdlc->data_bits++;
+ if(hdlc->hdlc_bits1 == 5){
+ hdlc->hdlc_bits1 = 0;
+ break;
+ }
+ if(hdlc->bit_shift==8){
+ hdlc->crc = crc_ccitt_byte(hdlc->crc, hdlc->shift_reg);
+ }
+ if(hdlc->shift_reg & 0x01){
+ hdlc->hdlc_bits1++;
+ hdlc->cbin++;
+ hdlc->shift_reg >>= 1;
+ hdlc->bit_shift--;
+ } else {
+ hdlc->hdlc_bits1 = 0;
+ hdlc->shift_reg >>= 1;
+ hdlc->bit_shift--;
+ }
+ break;
+ case HDLC_SEND_CRC1:
+ hdlc->cbin <<= 1;
+ hdlc->data_bits++;
+ if(hdlc->hdlc_bits1 == 5){
+ hdlc->hdlc_bits1 = 0;
+ break;
+ }
+ if(hdlc->shift_reg & 0x01){
+ hdlc->hdlc_bits1++;
+ hdlc->cbin++;
+ hdlc->shift_reg >>= 1;
+ hdlc->bit_shift--;
+ } else {
+ hdlc->hdlc_bits1 = 0;
+ hdlc->shift_reg >>= 1;
+ hdlc->bit_shift--;
+ }
+ if(hdlc->bit_shift==0){
+ hdlc->shift_reg = (hdlc->crc >> 8);
+ hdlc->state = HDLC_SEND_CRC2;
+ hdlc->bit_shift = 8;
+ }
+ break;
+ case HDLC_SEND_CRC2:
+ hdlc->cbin <<= 1;
+ hdlc->data_bits++;
+ if(hdlc->hdlc_bits1 == 5){
+ hdlc->hdlc_bits1 = 0;
+ break;
+ }
+ if(hdlc->shift_reg & 0x01){
+ hdlc->hdlc_bits1++;
+ hdlc->cbin++;
+ hdlc->shift_reg >>= 1;
+ hdlc->bit_shift--;
+ } else {
+ hdlc->hdlc_bits1 = 0;
+ hdlc->shift_reg >>= 1;
+ hdlc->bit_shift--;
+ }
+ if(hdlc->bit_shift==0){
+ hdlc->shift_reg = 0x7e;
+ hdlc->state = HDLC_SEND_CLOSING_FLAG;
+ hdlc->bit_shift = 8;
+ }
+ break;
+ case HDLC_SEND_CLOSING_FLAG:
+ hdlc->cbin <<= 1;
+ hdlc->data_bits++;
+ if(hdlc->hdlc_bits1 == 5){
+ hdlc->hdlc_bits1 = 0;
+ break;
+ }
+ if(hdlc->shift_reg & 0x01){
+ hdlc->cbin++;
+ }
+ hdlc->shift_reg >>= 1;
+ hdlc->bit_shift--;
+ if(hdlc->bit_shift==0){
+ hdlc->ffvalue = xfast_flag_value[hdlc->data_bits];
+ if(hdlc->dchannel){
+ hdlc->ffvalue = 0x7e;
+ hdlc->state = HDLC_SEND_IDLE1;
+ hdlc->bit_shift = 8-hdlc->data_bits;
+ if(hdlc->bit_shift==0)
+ hdlc->state = HDLC_SEND_FAST_IDLE;
+ } else {
+ if(!hdlc->do_adapt56){
+ hdlc->state = HDLC_SEND_FAST_FLAG;
+ hdlc->data_received = 0;
+ } else {
+ hdlc->state = HDLC_SENDFLAG_B0;
+ hdlc->data_received = 0;
+ }
+ // Finished with this frame, send flags
+ if (dsize > 1) dsize = 1;
+ }
+ }
+ break;
+ case HDLC_SEND_IDLE1:
+ hdlc->do_closing = 0;
+ hdlc->cbin <<= 1;
+ hdlc->cbin++;
+ hdlc->data_bits++;
+ hdlc->bit_shift--;
+ if(hdlc->bit_shift==0){
+ hdlc->state = HDLC_SEND_FAST_IDLE;
+ hdlc->bit_shift = 0;
+ }
+ break;
+ case HDLC_SEND_FAST_IDLE:
+ hdlc->do_closing = 0;
+ hdlc->cbin = 0xff;
+ hdlc->data_bits = 8;
+ if(hdlc->bit_shift == 8){
+ hdlc->cbin = 0x7e;
+ hdlc->state = HDLC_SEND_FIRST_FLAG;
+ } else {
+ *dst++ = hdlc->cbin;
+ hdlc->bit_shift = hdlc->data_bits = 0;
+ len++;
+ dsize = 0;
+ }
+ break;
+ default:
+ break;
+ }
+ if(hdlc->do_adapt56){
+ if(hdlc->data_bits==7){
+ hdlc->cbin <<= 1;
+ hdlc->cbin++;
+ hdlc->data_bits++;
+ }
+ }
+ if(hdlc->data_bits==8){
+ *dst++ = hdlc->cbin;
+ hdlc->data_bits = 0;
+ len++;
+ dsize--;
+ }
+ }
+ *count -= slen;
+
+ return len;
+}
+
+EXPORT_SYMBOL(isdnhdlc_rcv_init);
+EXPORT_SYMBOL(isdnhdlc_decode);
+EXPORT_SYMBOL(isdnhdlc_out_init);
+EXPORT_SYMBOL(isdnhdlc_encode);
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-14 00:21:37 +0300