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ISDN: Clean up isdnhdlc code

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Clean up isdnhdlc to meet current code standard.
Remove hint to already removed bit reversal table.

Signed-off-by: Karsten Keil <keil@b1-systems.de>
This commit is contained in:
Karsten Keil
2009-07-08 19:11:09 +02:00
parent cb3824bade
commit 6bd4bcd3cd
2 changed files with 231 additions and 203 deletions
Download Patch File Download Diff File Expand all files Collapse all files

190
drivers/isdn/i4l/isdnhdlc.c
View File

@@ -1,7 +1,8 @@
/* /*
* isdnhdlc.c -- General purpose ISDN HDLC decoder. * isdnhdlc.c -- General purpose ISDN HDLC decoder.
* *
*Copyright (C) 2002 Wolfgang Mües <wolfgang@iksw-muees.de> * Copyright (C)
* 2002 Wolfgang Mües <wolfgang@iksw-muees.de>
* 2001 Frode Isaksen <fisaksen@bewan.com> * 2001 Frode Isaksen <fisaksen@bewan.com>
* 2001 Kai Germaschewski <kai.germaschewski@gmx.de> * 2001 Kai Germaschewski <kai.germaschewski@gmx.de>
* *
@@ -63,8 +64,10 @@ void isdnhdlc_rcv_init (struct isdnhdlc_vars *hdlc, int do_adapt56)
hdlc->ffvalue = 0; hdlc->ffvalue = 0;
hdlc->dstpos = 0; hdlc->dstpos = 0;
} }
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, int is_d_channel,
int do_adapt56)
{ {
hdlc->bit_shift = 0; hdlc->bit_shift = 0;
hdlc->hdlc_bits1 = 0; hdlc->hdlc_bits1 = 0;
@@ -93,6 +96,25 @@ void isdnhdlc_out_init (struct isdnhdlc_vars *hdlc, int is_d_channel, int do_ada
} }
hdlc->shift_reg = 0; hdlc->shift_reg = 0;
} }
EXPORT_SYMBOL(isdnhdlc_rcv_init);
static int
check_frame(struct isdnhdlc_vars *hdlc)
{
int status;
if (hdlc->dstpos < 2) /* too small - framing error */
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;
}
return status;
}
/* /*
isdnhdlc_decode - decodes HDLC frames from a transparent bit stream. isdnhdlc_decode - decodes HDLC frames from a transparent bit stream.
@@ -121,8 +143,8 @@ void isdnhdlc_out_init (struct isdnhdlc_vars *hdlc, int is_d_channel, int do_ada
returns - number of decoded bytes in the destination buffer and status returns - number of decoded bytes in the destination buffer and status
flag. flag.
*/ */
int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src, int isdnhdlc_decode(struct isdnhdlc_vars *hdlc, const u8 *src, int slen,
int slen, int *count, unsigned char *dst, int dsize) int *count, u8 *dst, int dsize)
{ {
int status = 0; int status = 0;
@@ -138,6 +160,30 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src,
0x00, 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff 0x00, 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff
}; };
#define handle_fast_flag(h) \
do {\
if (h->cbin == fast_flag[h->bit_shift]) {\
h->ffvalue = fast_flag_value[h->bit_shift];\
h->state = HDLC_FAST_FLAG;\
h->ffbit_shift = h->bit_shift;\
h->bit_shift = 1;\
} else {\
h->state = HDLC_GET_DATA;\
h->data_received = 0;\
} \
} while (0)
#define handle_abort(h) \
do {\
h->shift_reg = fast_abort[h->ffbit_shift - 1];\
h->hdlc_bits1 = h->ffbit_shift - 2;\
if (h->hdlc_bits1 < 0)\
h->hdlc_bits1 = 0;\
h->data_bits = h->ffbit_shift - 1;\
h->state = HDLC_GET_DATA;\
h->data_received = 0;\
} while (0)
*count = slen; *count = slen;
while (slen > 0) { while (slen > 0) {
@@ -145,10 +191,9 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src,
hdlc->cbin = *src++; hdlc->cbin = *src++;
slen--; slen--;
hdlc->bit_shift = 8; hdlc->bit_shift = 8;
if(hdlc->do_adapt56){ if (hdlc->do_adapt56)
hdlc->bit_shift--; hdlc->bit_shift--;
} }
}
switch (hdlc->state) { switch (hdlc->state) {
case STOPPED: case STOPPED:
@@ -167,23 +212,21 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src,
hdlc->state = HDLC_GETFLAG_B1A6; hdlc->state = HDLC_GETFLAG_B1A6;
hdlc->hdlc_bits1 = 0; hdlc->hdlc_bits1 = 0;
} else { } else {
if(!hdlc->do_adapt56){ if ((!hdlc->do_adapt56) &&
if(++hdlc->hdlc_bits1 >=8 ) if(hdlc->bit_shift==1) (++hdlc->hdlc_bits1 >= 8) &&
(hdlc->bit_shift == 1))
hdlc->state = HDLC_FAST_IDLE; hdlc->state = HDLC_FAST_IDLE;
} }
}
hdlc->cbin <<= 1; hdlc->cbin <<= 1;
hdlc->bit_shift--; hdlc->bit_shift--;
break; break;
case HDLC_GETFLAG_B1A6: case HDLC_GETFLAG_B1A6:
if (hdlc->cbin & 0x80) { if (hdlc->cbin & 0x80) {
hdlc->hdlc_bits1++; hdlc->hdlc_bits1++;
if(hdlc->hdlc_bits1==6){ if (hdlc->hdlc_bits1 == 6)
hdlc->state = HDLC_GETFLAG_B7; hdlc->state = HDLC_GETFLAG_B7;
} } else
} else {
hdlc->hdlc_bits1 = 0; hdlc->hdlc_bits1 = 0;
}
hdlc->cbin <<= 1; hdlc->cbin <<= 1;
hdlc->bit_shift--; hdlc->bit_shift--;
break; break;
@@ -208,19 +251,19 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src,
case 6: case 6:
break; break;
case 7: case 7:
if(hdlc->data_received) { if (hdlc->data_received)
// bad frame /* bad frame */
status = -HDLC_FRAMING_ERROR; status = -HDLC_FRAMING_ERROR;
}
if (!hdlc->do_adapt56) { if (!hdlc->do_adapt56) {
if(hdlc->cbin==fast_abort[hdlc->bit_shift+1]){ if (hdlc->cbin == fast_abort
hdlc->state = HDLC_FAST_IDLE; [hdlc->bit_shift + 1]) {
hdlc->state =
HDLC_FAST_IDLE;
hdlc->bit_shift = 1; hdlc->bit_shift = 1;
break; break;
} }
} else { } else
hdlc->state = HDLC_GET_FLAG_B0; hdlc->state = HDLC_GET_FLAG_B0;
}
break; break;
default: default:
hdlc->shift_reg >>= 1; hdlc->shift_reg >>= 1;
@@ -233,33 +276,14 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src,
case 5: case 5:
break; break;
case 6: case 6:
if(hdlc->data_received){ if (hdlc->data_received)
if (hdlc->dstpos < 2) { status = check_frame(hdlc);
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->crc = 0xffff;
hdlc->shift_reg = 0; hdlc->shift_reg = 0;
hdlc->data_bits = 0; hdlc->data_bits = 0;
if(!hdlc->do_adapt56){ if (!hdlc->do_adapt56)
if(hdlc->cbin==fast_flag[hdlc->bit_shift]){ handle_fast_flag(hdlc);
hdlc->ffvalue = fast_flag_value[hdlc->bit_shift]; else {
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->state = HDLC_GET_DATA;
hdlc->data_received = 0; hdlc->data_received = 0;
} }
@@ -281,13 +305,14 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src,
if (hdlc->data_bits == 8) { if (hdlc->data_bits == 8) {
hdlc->data_bits = 0; hdlc->data_bits = 0;
hdlc->data_received = 1; hdlc->data_received = 1;
hdlc->crc = crc_ccitt_byte(hdlc->crc, hdlc->shift_reg); hdlc->crc = crc_ccitt_byte(hdlc->crc,
hdlc->shift_reg);
// good byte received /* good byte received */
if (hdlc->dstpos < dsize) { if (hdlc->dstpos < dsize)
dst[hdlc->dstpos++] = hdlc->shift_reg; dst[hdlc->dstpos++] = hdlc->shift_reg;
} else { else {
// frame too long /* frame too long */
status = -HDLC_LENGTH_ERROR; status = -HDLC_LENGTH_ERROR;
hdlc->dstpos = 0; hdlc->dstpos = 0;
} }
@@ -306,14 +331,8 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src,
} else if (hdlc->ffbit_shift == 8) { } else if (hdlc->ffbit_shift == 8) {
hdlc->state = HDLC_GETFLAG_B7; hdlc->state = HDLC_GETFLAG_B7;
break; break;
} else { } else
hdlc->shift_reg = fast_abort[hdlc->ffbit_shift-1]; handle_abort(hdlc);
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; break;
default: default:
@@ -323,7 +342,7 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src,
*count -= slen; *count -= slen;
return 0; return 0;
} }
EXPORT_SYMBOL(isdnhdlc_decode);
/* /*
isdnhdlc_encode - encodes HDLC frames to a transparent bit stream. isdnhdlc_encode - encodes HDLC frames to a transparent bit stream.
@@ -343,9 +362,8 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src,
dsize - destination buffer size dsize - destination buffer size
returns - number of encoded bytes in the destination buffer returns - number of encoded bytes in the destination buffer
*/ */
int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const unsigned char *src, int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const u8 *src, u16 slen,
unsigned short slen, int *count, int *count, u8 *dst, int dsize)
unsigned char *dst, int dsize)
{ {
static const unsigned char xfast_flag_value[] = { static const unsigned char xfast_flag_value[] = {
0x7e, 0x3f, 0x9f, 0xcf, 0xe7, 0xf3, 0xf9, 0xfc, 0x7e 0x7e, 0x3f, 0x9f, 0xcf, 0xe7, 0xf3, 0xf9, 0xfc, 0x7e
@@ -361,7 +379,8 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const unsigned char *src,
hdlc->shift_reg = *src++; hdlc->shift_reg = *src++;
slen--; slen--;
if (slen == 0) if (slen == 0)
hdlc->do_closing = 1; /* closing sequence, CRC + flag(s) */ /* closing sequence, CRC + flag(s) */
hdlc->do_closing = 1;
hdlc->bit_shift = 8; hdlc->bit_shift = 8;
} else { } else {
if (hdlc->state == HDLC_SEND_DATA) { if (hdlc->state == HDLC_SEND_DATA) {
@@ -369,12 +388,14 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const unsigned char *src,
hdlc->state = HDLC_SEND_CRC1; hdlc->state = HDLC_SEND_CRC1;
hdlc->crc ^= 0xffff; hdlc->crc ^= 0xffff;
hdlc->bit_shift = 8; hdlc->bit_shift = 8;
hdlc->shift_reg = hdlc->crc & 0xff; hdlc->shift_reg =
} else if(!hdlc->do_adapt56){ hdlc->crc & 0xff;
hdlc->state = HDLC_SEND_FAST_FLAG; } else if (!hdlc->do_adapt56)
} else { hdlc->state =
hdlc->state = HDLC_SENDFLAG_B0; HDLC_SEND_FAST_FLAG;
} else
hdlc->state =
HDLC_SENDFLAG_B0;
} }
} }
@@ -395,7 +416,8 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const unsigned char *src,
break; break;
} }
if (hdlc->bit_shift == 8) { if (hdlc->bit_shift == 8) {
hdlc->cbin = hdlc->ffvalue>>(8-hdlc->data_bits); hdlc->cbin = hdlc->ffvalue >>
(8 - hdlc->data_bits);
hdlc->state = HDLC_SEND_DATA; hdlc->state = HDLC_SEND_DATA;
hdlc->crc = 0xffff; hdlc->crc = 0xffff;
hdlc->hdlc_bits1 = 0; hdlc->hdlc_bits1 = 0;
@@ -457,9 +479,9 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const unsigned char *src,
hdlc->hdlc_bits1 = 0; hdlc->hdlc_bits1 = 0;
break; break;
} }
if(hdlc->bit_shift==8){ if (hdlc->bit_shift == 8)
hdlc->crc = crc_ccitt_byte(hdlc->crc, hdlc->shift_reg); hdlc->crc = crc_ccitt_byte(hdlc->crc,
} hdlc->shift_reg);
if (hdlc->shift_reg & 0x01) { if (hdlc->shift_reg & 0x01) {
hdlc->hdlc_bits1++; hdlc->hdlc_bits1++;
hdlc->cbin++; hdlc->cbin++;
@@ -524,29 +546,32 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const unsigned char *src,
hdlc->hdlc_bits1 = 0; hdlc->hdlc_bits1 = 0;
break; break;
} }
if(hdlc->shift_reg & 0x01){ if (hdlc->shift_reg & 0x01)
hdlc->cbin++; hdlc->cbin++;
}
hdlc->shift_reg >>= 1; hdlc->shift_reg >>= 1;
hdlc->bit_shift--; hdlc->bit_shift--;
if (hdlc->bit_shift == 0) { if (hdlc->bit_shift == 0) {
hdlc->ffvalue = xfast_flag_value[hdlc->data_bits]; hdlc->ffvalue =
xfast_flag_value[hdlc->data_bits];
if (hdlc->dchannel) { if (hdlc->dchannel) {
hdlc->ffvalue = 0x7e; hdlc->ffvalue = 0x7e;
hdlc->state = HDLC_SEND_IDLE1; hdlc->state = HDLC_SEND_IDLE1;
hdlc->bit_shift = 8-hdlc->data_bits; hdlc->bit_shift = 8-hdlc->data_bits;
if (hdlc->bit_shift == 0) if (hdlc->bit_shift == 0)
hdlc->state = HDLC_SEND_FAST_IDLE; hdlc->state =
HDLC_SEND_FAST_IDLE;
} else { } else {
if (!hdlc->do_adapt56) { if (!hdlc->do_adapt56) {
hdlc->state = HDLC_SEND_FAST_FLAG; hdlc->state =
HDLC_SEND_FAST_FLAG;
hdlc->data_received = 0; hdlc->data_received = 0;
} else { } else {
hdlc->state = HDLC_SENDFLAG_B0; hdlc->state = HDLC_SENDFLAG_B0;
hdlc->data_received = 0; hdlc->data_received = 0;
} }
// Finished with this frame, send flags /* Finished this frame, send flags */
if (dsize > 1) dsize = 1; if (dsize > 1)
dsize = 1;
} }
} }
break; break;
@@ -570,7 +595,8 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const unsigned char *src,
hdlc->state = HDLC_SEND_FIRST_FLAG; hdlc->state = HDLC_SEND_FIRST_FLAG;
} else { } else {
*dst++ = hdlc->cbin; *dst++ = hdlc->cbin;
hdlc->bit_shift = hdlc->data_bits = 0; hdlc->bit_shift = 0;
hdlc->data_bits = 0;
len++; len++;
dsize = 0; dsize = 0;
} }
@@ -596,8 +622,4 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const unsigned char *src,
return len; return len;
} }
EXPORT_SYMBOL(isdnhdlc_rcv_init);
EXPORT_SYMBOL(isdnhdlc_decode);
EXPORT_SYMBOL(isdnhdlc_out_init);
EXPORT_SYMBOL(isdnhdlc_encode); EXPORT_SYMBOL(isdnhdlc_encode);

40
include/linux/isdn/hdlc.h
View File

@@ -1,11 +1,12 @@
/* /*
* isdnhdlc.h -- General purpose ISDN HDLC decoder. * hdlc.h -- General purpose ISDN HDLC decoder.
* *
* Implementation of a HDLC decoder/encoder in software. * Implementation of a HDLC decoder/encoder in software.
* Neccessary because some ISDN devices don't have HDLC * Neccessary because some ISDN devices don't have HDLC
* controllers. Also included: a bit reversal table. * controllers.
* *
*Copyright (C) 2002 Wolfgang Mües <wolfgang@iksw-muees.de> * Copyright (C)
* 2002 Wolfgang Mües <wolfgang@iksw-muees.de>
* 2001 Frode Isaksen <fisaksen@bewan.com> * 2001 Frode Isaksen <fisaksen@bewan.com>
* 2001 Kai Germaschewski <kai.germaschewski@gmx.de> * 2001 Kai Germaschewski <kai.germaschewski@gmx.de>
* *
@@ -31,20 +32,24 @@ struct isdnhdlc_vars {
int bit_shift; int bit_shift;
int hdlc_bits1; int hdlc_bits1;
int data_bits; int data_bits;
int ffbit_shift; // encoding only int ffbit_shift; /* encoding only */
int state; int state;
int dstpos; int dstpos;
unsigned short crc; u16 crc;
unsigned char cbin; u8 cbin;
unsigned char shift_reg; u8 shift_reg;
unsigned char ffvalue; u8 ffvalue;
unsigned int data_received:1; // set if transferring data /* set if transferring data */
unsigned int dchannel:1; // set if D channel (send idle instead of flags) u32 data_received:1;
unsigned int do_adapt56:1; // set if 56K adaptation /* set if D channel (send idle instead of flags) */
unsigned int do_closing:1; // set if in closing phase (need to send CRC + flag u32 dchannel:1;
/* set if 56K adaptation */
u32 do_adapt56:1;
/* set if in closing phase (need to send CRC + flag) */
u32 do_closing:1;
}; };
@@ -59,12 +64,13 @@ struct isdnhdlc_vars {
extern void isdnhdlc_rcv_init(struct isdnhdlc_vars *hdlc, int do_adapt56); extern void isdnhdlc_rcv_init(struct isdnhdlc_vars *hdlc, int do_adapt56);
extern int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src, int slen,int *count, extern int isdnhdlc_decode(struct isdnhdlc_vars *hdlc, const u8 *src,
unsigned char *dst, int dsize); int slen, int *count, u8 *dst, int dsize);
extern void isdnhdlc_out_init (struct isdnhdlc_vars *hdlc,int is_d_channel,int do_adapt56); extern void isdnhdlc_out_init(struct isdnhdlc_vars *hdlc, int is_d_channel,
int do_adapt56);
extern int isdnhdlc_encode (struct isdnhdlc_vars *hdlc,const unsigned char *src,unsigned short slen,int *count, extern int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const u8 *src,
unsigned char *dst,int dsize); u16 slen, int *count, u8 *dst, int dsize);
#endif /* __ISDNHDLC_H__ */ #endif /* __ISDNHDLC_H__ */