linux/drivers/isdn/i4l/isdn_v110.c
Jesper Juhl 1e1a5cc77e [PATCH] isdn_v110 warning fix
Here's a small warning fix for drivers/isdn/i4l/isdn_v110.c
 drivers/isdn/i4l/isdn_v110.c:523: warning: `ret' might be used uninitialized in this function

In addition to Karsten Keil signing off on the patch, Thomas Pfeiffer also
commented on the patch, saying
"initializing ret with the value zero is correct and should be done."

Please apply.

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07 16:57:36 -07:00

618 lines
16 KiB
C

/* $Id: isdn_v110.c,v 1.1.2.2 2004/01/12 22:37:19 keil Exp $
*
* Linux ISDN subsystem, V.110 related functions (linklevel).
*
* Copyright by Thomas Pfeiffer (pfeiffer@pds.de)
*
* This software may be used and distributed according to the terms
* of the GNU General Public License, incorporated herein by reference.
*
*/
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/isdn.h>
#include "isdn_v110.h"
#undef ISDN_V110_DEBUG
char *isdn_v110_revision = "$Revision: 1.1.2.2 $";
#define V110_38400 255
#define V110_19200 15
#define V110_9600 3
/*
* The following data are precoded matrices, online and offline matrix
* for 9600, 19200 und 38400, respectively
*/
static unsigned char V110_OnMatrix_9600[] =
{0xfc, 0xfc, 0xfc, 0xfc, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff,
0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd,
0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff,
0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd};
static unsigned char V110_OffMatrix_9600[] =
{0xfc, 0xfc, 0xfc, 0xfc, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
static unsigned char V110_OnMatrix_19200[] =
{0xf0, 0xf0, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7,
0xfd, 0xff, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7};
static unsigned char V110_OffMatrix_19200[] =
{0xf0, 0xf0, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
static unsigned char V110_OnMatrix_38400[] =
{0x00, 0x7f, 0x7f, 0x7f, 0x7f, 0xfd, 0x7f, 0x7f, 0x7f, 0x7f};
static unsigned char V110_OffMatrix_38400[] =
{0x00, 0xff, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xff};
/*
* FlipBits reorders sequences of keylen bits in one byte.
* E.g. source order 7654321 will be converted to 45670123 when keylen = 4,
* and to 67452301 when keylen = 2. This is necessary because ordering on
* the isdn line is the other way.
*/
static __inline unsigned char
FlipBits(unsigned char c, int keylen)
{
unsigned char b = c;
unsigned char bit = 128;
int i;
int j;
int hunks = (8 / keylen);
c = 0;
for (i = 0; i < hunks; i++) {
for (j = 0; j < keylen; j++) {
if (b & (bit >> j))
c |= bit >> (keylen - j - 1);
}
bit >>= keylen;
}
return c;
}
/* isdn_v110_open allocates and initializes private V.110 data
* structures and returns a pointer to these.
*/
static isdn_v110_stream *
isdn_v110_open(unsigned char key, int hdrlen, int maxsize)
{
int i;
isdn_v110_stream *v;
if ((v = kmalloc(sizeof(isdn_v110_stream), GFP_ATOMIC)) == NULL)
return NULL;
memset(v, 0, sizeof(isdn_v110_stream));
v->key = key;
v->nbits = 0;
for (i = 0; key & (1 << i); i++)
v->nbits++;
v->nbytes = 8 / v->nbits;
v->decodelen = 0;
switch (key) {
case V110_38400:
v->OnlineFrame = V110_OnMatrix_38400;
v->OfflineFrame = V110_OffMatrix_38400;
break;
case V110_19200:
v->OnlineFrame = V110_OnMatrix_19200;
v->OfflineFrame = V110_OffMatrix_19200;
break;
default:
v->OnlineFrame = V110_OnMatrix_9600;
v->OfflineFrame = V110_OffMatrix_9600;
break;
}
v->framelen = v->nbytes * 10;
v->SyncInit = 5;
v->introducer = 0;
v->dbit = 1;
v->b = 0;
v->skbres = hdrlen;
v->maxsize = maxsize - hdrlen;
if ((v->encodebuf = kmalloc(maxsize, GFP_ATOMIC)) == NULL) {
kfree(v);
return NULL;
}
return v;
}
/* isdn_v110_close frees private V.110 data structures */
void
isdn_v110_close(isdn_v110_stream * v)
{
if (v == NULL)
return;
#ifdef ISDN_V110_DEBUG
printk(KERN_DEBUG "v110 close\n");
#endif
kfree(v->encodebuf);
kfree(v);
}
/*
* ValidHeaderBytes return the number of valid bytes in v->decodebuf
*/
static int
ValidHeaderBytes(isdn_v110_stream * v)
{
int i;
for (i = 0; (i < v->decodelen) && (i < v->nbytes); i++)
if ((v->decodebuf[i] & v->key) != 0)
break;
return i;
}
/*
* SyncHeader moves the decodebuf ptr to the next valid header
*/
static void
SyncHeader(isdn_v110_stream * v)
{
unsigned char *rbuf = v->decodebuf;
int len = v->decodelen;
if (len == 0)
return;
for (rbuf++, len--; len > 0; len--, rbuf++) /* such den SyncHeader in buf ! */
if ((*rbuf & v->key) == 0) /* erstes byte gefunden ? */
break; /* jupp! */
if (len)
memcpy(v->decodebuf, rbuf, len);
v->decodelen = len;
#ifdef ISDN_V110_DEBUG
printk(KERN_DEBUG "isdn_v110: Header resync\n");
#endif
}
/* DecodeMatrix takes n (n>=1) matrices (v110 frames, 10 bytes) where
len is the number of matrix-lines. len must be a multiple of 10, i.e.
only complete matices must be given.
From these, netto data is extracted and returned in buf. The return-value
is the bytecount of the decoded data.
*/
static int
DecodeMatrix(isdn_v110_stream * v, unsigned char *m, int len, unsigned char *buf)
{
int line = 0;
int buflen = 0;
int mbit = 64;
int introducer = v->introducer;
int dbit = v->dbit;
unsigned char b = v->b;
while (line < len) { /* Are we done with all lines of the matrix? */
if ((line % 10) == 0) { /* the 0. line of the matrix is always 0 ! */
if (m[line] != 0x00) { /* not 0 ? -> error! */
#ifdef ISDN_V110_DEBUG
printk(KERN_DEBUG "isdn_v110: DecodeMatrix, V110 Bad Header\n");
/* returning now is not the right thing, though :-( */
#endif
}
line++; /* next line of matrix */
continue;
} else if ((line % 10) == 5) { /* in line 5 there's only e-bits ! */
if ((m[line] & 0x70) != 0x30) { /* 011 has to be at the beginning! */
#ifdef ISDN_V110_DEBUG
printk(KERN_DEBUG "isdn_v110: DecodeMatrix, V110 Bad 5th line\n");
/* returning now is not the right thing, though :-( */
#endif
}
line++; /* next line */
continue;
} else if (!introducer) { /* every byte starts with 10 (stopbit, startbit) */
introducer = (m[line] & mbit) ? 0 : 1; /* current bit of the matrix */
next_byte:
if (mbit > 2) { /* was it the last bit in this line ? */
mbit >>= 1; /* no -> take next */
continue;
} /* otherwise start with leftmost bit in the next line */
mbit = 64;
line++;
continue;
} else { /* otherwise we need to set a data bit */
if (m[line] & mbit) /* was that bit set in the matrix ? */
b |= dbit; /* yes -> set it in the data byte */
else
b &= dbit - 1; /* no -> clear it in the data byte */
if (dbit < 128) /* is that data byte done ? */
dbit <<= 1; /* no, got the next bit */
else { /* data byte is done */
buf[buflen++] = b; /* copy byte into the output buffer */
introducer = b = 0; /* init of the intro sequence and of the data byte */
dbit = 1; /* next we look for the 0th bit */
}
goto next_byte; /* look for next bit in the matrix */
}
}
v->introducer = introducer;
v->dbit = dbit;
v->b = b;
return buflen; /* return number of bytes in the output buffer */
}
/*
* DecodeStream receives V.110 coded data from the input stream. It recovers the
* original frames.
* The input stream doesn't need to be framed
*/
struct sk_buff *
isdn_v110_decode(isdn_v110_stream * v, struct sk_buff *skb)
{
int i;
int j;
int len;
unsigned char *v110_buf;
unsigned char *rbuf;
if (!skb) {
printk(KERN_WARNING "isdn_v110_decode called with NULL skb!\n");
return NULL;
}
rbuf = skb->data;
len = skb->len;
if (v == NULL) {
/* invalid handle, no chance to proceed */
printk(KERN_WARNING "isdn_v110_decode called with NULL stream!\n");
dev_kfree_skb(skb);
return NULL;
}
if (v->decodelen == 0) /* cache empty? */
for (; len > 0; len--, rbuf++) /* scan for SyncHeader in buf */
if ((*rbuf & v->key) == 0)
break; /* found first byte */
if (len == 0) {
dev_kfree_skb(skb);
return NULL;
}
/* copy new data to decode-buffer */
memcpy(&(v->decodebuf[v->decodelen]), rbuf, len);
v->decodelen += len;
ReSync:
if (v->decodelen < v->nbytes) { /* got a new header ? */
dev_kfree_skb(skb);
return NULL; /* no, try later */
}
if (ValidHeaderBytes(v) != v->nbytes) { /* is that a valid header? */
SyncHeader(v); /* no -> look for header */
goto ReSync;
}
len = (v->decodelen - (v->decodelen % (10 * v->nbytes))) / v->nbytes;
if ((v110_buf = kmalloc(len, GFP_ATOMIC)) == NULL) {
printk(KERN_WARNING "isdn_v110_decode: Couldn't allocate v110_buf\n");
dev_kfree_skb(skb);
return NULL;
}
for (i = 0; i < len; i++) {
v110_buf[i] = 0;
for (j = 0; j < v->nbytes; j++)
v110_buf[i] |= (v->decodebuf[(i * v->nbytes) + j] & v->key) << (8 - ((j + 1) * v->nbits));
v110_buf[i] = FlipBits(v110_buf[i], v->nbits);
}
v->decodelen = (v->decodelen % (10 * v->nbytes));
memcpy(v->decodebuf, &(v->decodebuf[len * v->nbytes]), v->decodelen);
skb_trim(skb, DecodeMatrix(v, v110_buf, len, skb->data));
kfree(v110_buf);
if (skb->len)
return skb;
else {
kfree_skb(skb);
return NULL;
}
}
/* EncodeMatrix takes input data in buf, len is the bytecount.
Data is encoded into v110 frames in m. Return value is the number of
matrix-lines generated.
*/
static int
EncodeMatrix(unsigned char *buf, int len, unsigned char *m, int mlen)
{
int line = 0;
int i = 0;
int mbit = 128;
int dbit = 1;
int introducer = 3;
int ibit[] = {0, 1, 1};
while ((i < len) && (line < mlen)) { /* while we still have input data */
switch (line % 10) { /* in which line of the matrix are we? */
case 0:
m[line++] = 0x00; /* line 0 is always 0 */
mbit = 128; /* go on with the 7th bit */
break;
case 5:
m[line++] = 0xbf; /* line 5 is always 10111111 */
mbit = 128; /* go on with the 7th bit */
break;
}
if (line >= mlen) {
printk(KERN_WARNING "isdn_v110 (EncodeMatrix): buffer full!\n");
return line;
}
next_bit:
switch (mbit) { /* leftmost or rightmost bit ? */
case 1:
line++; /* rightmost -> go to next line */
if (line >= mlen) {
printk(KERN_WARNING "isdn_v110 (EncodeMatrix): buffer full!\n");
return line;
}
case 128:
m[line] = 128; /* leftmost -> set byte to 1000000 */
mbit = 64; /* current bit in the matrix line */
continue;
}
if (introducer) { /* set 110 sequence ? */
introducer--; /* set on digit less */
m[line] |= ibit[introducer] ? mbit : 0; /* set corresponding bit */
mbit >>= 1; /* bit of matrix line >> 1 */
goto next_bit; /* and go on there */
} /* else push data bits into the matrix! */
m[line] |= (buf[i] & dbit) ? mbit : 0; /* set data bit in matrix */
if (dbit == 128) { /* was it the last one? */
dbit = 1; /* then go on with first bit of */
i++; /* next byte in input buffer */
if (i < len) /* input buffer done ? */
introducer = 3; /* no, write introducer 110 */
else { /* input buffer done ! */
m[line] |= (mbit - 1) & 0xfe; /* set remaining bits in line to 1 */
break;
}
} else /* not the last data bit */
dbit <<= 1; /* then go to next data bit */
mbit >>= 1; /* go to next bit of matrix */
goto next_bit;
}
/* if necessary, generate remaining lines of the matrix... */
if ((line) && ((line + 10) < mlen))
switch (++line % 10) {
case 1:
m[line++] = 0xfe;
case 2:
m[line++] = 0xfe;
case 3:
m[line++] = 0xfe;
case 4:
m[line++] = 0xfe;
case 5:
m[line++] = 0xbf;
case 6:
m[line++] = 0xfe;
case 7:
m[line++] = 0xfe;
case 8:
m[line++] = 0xfe;
case 9:
m[line++] = 0xfe;
}
return line; /* that's how many lines we have */
}
/*
* Build a sync frame.
*/
static struct sk_buff *
isdn_v110_sync(isdn_v110_stream *v)
{
struct sk_buff *skb;
if (v == NULL) {
/* invalid handle, no chance to proceed */
printk(KERN_WARNING "isdn_v110_sync called with NULL stream!\n");
return NULL;
}
if ((skb = dev_alloc_skb(v->framelen + v->skbres))) {
skb_reserve(skb, v->skbres);
memcpy(skb_put(skb, v->framelen), v->OfflineFrame, v->framelen);
}
return skb;
}
/*
* Build an idle frame.
*/
static struct sk_buff *
isdn_v110_idle(isdn_v110_stream *v)
{
struct sk_buff *skb;
if (v == NULL) {
/* invalid handle, no chance to proceed */
printk(KERN_WARNING "isdn_v110_sync called with NULL stream!\n");
return NULL;
}
if ((skb = dev_alloc_skb(v->framelen + v->skbres))) {
skb_reserve(skb, v->skbres);
memcpy(skb_put(skb, v->framelen), v->OnlineFrame, v->framelen);
}
return skb;
}
struct sk_buff *
isdn_v110_encode(isdn_v110_stream * v, struct sk_buff *skb)
{
int i;
int j;
int rlen;
int mlen;
int olen;
int size;
int sval1;
int sval2;
int nframes;
unsigned char *v110buf;
unsigned char *rbuf;
struct sk_buff *nskb;
if (v == NULL) {
/* invalid handle, no chance to proceed */
printk(KERN_WARNING "isdn_v110_encode called with NULL stream!\n");
return NULL;
}
if (!skb) {
/* invalid skb, no chance to proceed */
printk(KERN_WARNING "isdn_v110_encode called with NULL skb!\n");
return NULL;
}
rlen = skb->len;
nframes = (rlen + 3) / 4;
v110buf = v->encodebuf;
if ((nframes * 40) > v->maxsize) {
size = v->maxsize;
rlen = v->maxsize / 40;
} else
size = nframes * 40;
if (!(nskb = dev_alloc_skb(size + v->skbres + sizeof(int)))) {
printk(KERN_WARNING "isdn_v110_encode: Couldn't alloc skb\n");
return NULL;
}
skb_reserve(nskb, v->skbres + sizeof(int));
if (skb->len == 0) {
memcpy(skb_put(nskb, v->framelen), v->OnlineFrame, v->framelen);
*((int *)skb_push(nskb, sizeof(int))) = 0;
return nskb;
}
mlen = EncodeMatrix(skb->data, rlen, v110buf, size);
/* now distribute 2 or 4 bits each to the output stream! */
rbuf = skb_put(nskb, size);
olen = 0;
sval1 = 8 - v->nbits;
sval2 = v->key << sval1;
for (i = 0; i < mlen; i++) {
v110buf[i] = FlipBits(v110buf[i], v->nbits);
for (j = 0; j < v->nbytes; j++) {
if (size--)
*rbuf++ = ~v->key | (((v110buf[i] << (j * v->nbits)) & sval2) >> sval1);
else {
printk(KERN_WARNING "isdn_v110_encode: buffers full!\n");
goto buffer_full;
}
olen++;
}
}
buffer_full:
skb_trim(nskb, olen);
*((int *)skb_push(nskb, sizeof(int))) = rlen;
return nskb;
}
int
isdn_v110_stat_callback(int idx, isdn_ctrl *c)
{
isdn_v110_stream *v = NULL;
int i;
int ret = 0;
if (idx < 0)
return 0;
switch (c->command) {
case ISDN_STAT_BSENT:
/* Keep the send-queue of the driver filled
* with frames:
* If number of outstanding frames < 3,
* send down an Idle-Frame (or an Sync-Frame, if
* v->SyncInit != 0).
*/
if (!(v = dev->v110[idx]))
return 0;
atomic_inc(&dev->v110use[idx]);
for (i=0; i * v->framelen < c->parm.length; i++) {
if (v->skbidle > 0) {
v->skbidle--;
ret = 1;
} else {
if (v->skbuser > 0)
v->skbuser--;
ret = 0;
}
}
for (i = v->skbuser + v->skbidle; i < 2; i++) {
struct sk_buff *skb;
if (v->SyncInit > 0)
skb = isdn_v110_sync(v);
else
skb = isdn_v110_idle(v);
if (skb) {
if (dev->drv[c->driver]->interface->writebuf_skb(c->driver, c->arg, 1, skb) <= 0) {
dev_kfree_skb(skb);
break;
} else {
if (v->SyncInit)
v->SyncInit--;
v->skbidle++;
}
} else
break;
}
atomic_dec(&dev->v110use[idx]);
return ret;
case ISDN_STAT_DHUP:
case ISDN_STAT_BHUP:
while (1) {
atomic_inc(&dev->v110use[idx]);
if (atomic_dec_and_test(&dev->v110use[idx])) {
isdn_v110_close(dev->v110[idx]);
dev->v110[idx] = NULL;
break;
}
mdelay(1);
}
break;
case ISDN_STAT_BCONN:
if (dev->v110emu[idx] && (dev->v110[idx] == NULL)) {
int hdrlen = dev->drv[c->driver]->interface->hl_hdrlen;
int maxsize = dev->drv[c->driver]->interface->maxbufsize;
atomic_inc(&dev->v110use[idx]);
switch (dev->v110emu[idx]) {
case ISDN_PROTO_L2_V11096:
dev->v110[idx] = isdn_v110_open(V110_9600, hdrlen, maxsize);
break;
case ISDN_PROTO_L2_V11019:
dev->v110[idx] = isdn_v110_open(V110_19200, hdrlen, maxsize);
break;
case ISDN_PROTO_L2_V11038:
dev->v110[idx] = isdn_v110_open(V110_38400, hdrlen, maxsize);
break;
default:;
}
if ((v = dev->v110[idx])) {
while (v->SyncInit) {
struct sk_buff *skb = isdn_v110_sync(v);
if (dev->drv[c->driver]->interface->writebuf_skb(c->driver, c->arg, 1, skb) <= 0) {
dev_kfree_skb(skb);
/* Unable to send, try later */
break;
}
v->SyncInit--;
v->skbidle++;
}
} else
printk(KERN_WARNING "isdn_v110: Couldn't open stream for chan %d\n", idx);
atomic_dec(&dev->v110use[idx]);
}
break;
default:
return 0;
}
return 0;
}