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linux/drivers/isdn/gigaset/asyncdata.c

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/*
* Common data handling layer for ser_gigaset and usb_gigaset
*
* Copyright (c) 2005 by Tilman Schmidt <tilman@imap.cc>,
* Hansjoerg Lipp <hjlipp@web.de>,
* Stefan Eilers.
*
* =====================================================================
* 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.
* =====================================================================
*/
#include "gigaset.h"
#include <linux/crc-ccitt.h>
#include <linux/bitrev.h>
//#define GIG_M10x_STUFF_VOICE_DATA
/* 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
* less than 0x20, the flag sequence and the control escape char.
*/
static inline int muststuff(unsigned char c)
{
if (c < PPP_TRANS) return 1;
if (c == PPP_FLAG) return 1;
if (c == PPP_ESCAPE) return 1;
/* other possible candidates: */
/* 0x91: XON with parity set */
/* 0x93: XOFF with parity set */
return 0;
}
/* == data input =========================================================== */
/* process a block of received bytes in command mode (modem response)
* Return value:
* number of processed bytes
*/
static inline int cmd_loop(unsigned char c, unsigned char *src, int numbytes,
struct inbuf_t *inbuf)
{
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)",
__func__, cbytes);
cs->cbytes = cbytes;
gigaset_handle_modem_response(cs); /* can change
cs->dle */
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");
}
if (!numbytes)
break;
c = *src++;
--numbytes;
if (c == DLE_FLAG &&
(cs->dle || inputstate & INS_DLE_command)) {
inputstate |= INS_DLE_char;
break;
}
}
cs->cbytes = cbytes;
inbuf->inputstate = inputstate;
return startbytes - numbytes;
}
/* process a block of received bytes in lock mode (tty i/f)
* Return value:
* number of processed bytes
*/
static inline int lock_loop(unsigned char *src, int 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);
return numbytes;
}
/* process a block of received bytes in HDLC data mode
* 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)
{
struct cardstate *cs = inbuf->cs;
struct bc_state *bcs = inbuf->bcs;
int inputstate = bcs->inputstate;
__u16 fcs = bcs->fcs;
struct sk_buff *skb = bcs->skb;
unsigned char error;
struct sk_buff *compskb;
int startbytes = numbytes;
int l;
if (unlikely(inputstate & INS_byte_stuff)) {
inputstate &= ~INS_byte_stuff;
goto byte_stuff;
}
for (;;) {
if (unlikely(c == PPP_ESCAPE)) {
if (unlikely(!numbytes)) {
inputstate |= INS_byte_stuff;
break;
}
c = *src++;
--numbytes;
if (unlikely(c == DLE_FLAG &&
(cs->dle ||
inbuf->inputstate & INS_DLE_command))) {
inbuf->inputstate |= INS_DLE_char;
inputstate |= INS_byte_stuff;
break;
}
byte_stuff:
c ^= PPP_TRANS;
#ifdef CONFIG_GIGASET_DEBUG
if (unlikely(!muststuff(c)))
gig_dbg(DEBUG_HDLC, "byte stuffed: 0x%02x", c);
#endif
} else if (unlikely(c == PPP_FLAG)) {
if (unlikely(inputstate & INS_skip_frame)) {
if (!(inputstate & INS_have_data)) { /* 7E 7E */
#ifdef CONFIG_GIGASET_DEBUG
++bcs->emptycount;
#endif
} else
gig_dbg(DEBUG_HDLC,
"7e----------------------------");
/* end of frame */
error = 1;
gigaset_rcv_error(NULL, cs, bcs);
} else if (!(inputstate & INS_have_data)) { /* 7E 7E */
#ifdef CONFIG_GIGASET_DEBUG
++bcs->emptycount;
#endif
break;
} else {
gig_dbg(DEBUG_HDLC,
"7e----------------------------");
/* end of frame */
error = 0;
if (unlikely(fcs != PPP_GOODFCS)) {
dev_err(cs->dev,
"Packet checksum at %lu failed, "
"packet is corrupted (%u bytes)!\n",
bcs->rcvbytes, skb->len);
compskb = NULL;
gigaset_rcv_error(compskb, cs, bcs);
error = 1;
} else {
if (likely((l = skb->len) > 2)) {
skb->tail -= 2;
skb->len -= 2;
} else {
dev_kfree_skb(skb);
skb = NULL;
inputstate |= INS_skip_frame;
if (l == 1) {
dev_err(cs->dev,
"invalid packet size (1)!\n");
error = 1;
gigaset_rcv_error(NULL,
cs, bcs);
}
}
if (likely(!(error ||
(inputstate &
INS_skip_frame)))) {
gigaset_rcv_skb(skb, cs, bcs);
}
}
}
if (unlikely(error))
if (skb)
dev_kfree_skb(skb);
fcs = PPP_INITFCS;
inputstate &= ~(INS_have_data | INS_skip_frame);
if (unlikely(bcs->ignore)) {
inputstate |= INS_skip_frame;
skb = NULL;
} else if (likely((skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN)) != NULL)) {
skb_reserve(skb, HW_HDR_LEN);
} else {
dev_warn(cs->dev,
"could not allocate new skb\n");
inputstate |= INS_skip_frame;
}
break;
#ifdef CONFIG_GIGASET_DEBUG
} else if (unlikely(muststuff(c))) {
/* Should not happen. Possible after ZDLE=1<CR><LF>. */
gig_dbg(DEBUG_HDLC, "not byte stuffed: 0x%02x", c);
#endif
}
/* add character */
#ifdef CONFIG_GIGASET_DEBUG
if (unlikely(!(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)) {
dev_warn(cs->dev, "received packet too long\n");
dev_kfree_skb_any(skb);
skb = NULL;
inputstate |= INS_skip_frame;
break;
}
*__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;
}
/* process a block of received bytes in transparent data mode
* 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)
{
struct cardstate *cs = inbuf->cs;
struct bc_state *bcs = inbuf->bcs;
int inputstate = bcs->inputstate;
struct sk_buff *skb = bcs->skb;
int startbytes = numbytes;
for (;;) {
/* add character */
inputstate |= INS_have_data;
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;
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;
}
}
/* pass data up */
if (likely(inputstate & INS_have_data)) {
if (likely(!(inputstate & INS_skip_frame))) {
gigaset_rcv_skb(skb, cs, bcs);
}
inputstate &= ~(INS_have_data | INS_skip_frame);
if (unlikely(bcs->ignore)) {
inputstate |= INS_skip_frame;
skb = NULL;
} else if (likely((skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN))
!= NULL)) {
skb_reserve(skb, HW_HDR_LEN);
} else {
dev_warn(cs->dev, "could not allocate new skb\n");
inputstate |= INS_skip_frame;
}
}
bcs->inputstate = inputstate;
bcs->skb = skb;
return startbytes - numbytes;
}
/* process a block of data received from the device
*/
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);
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;
}
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 == ISDN_PROTO_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*/
#ifdef CONFIG_GIGASET_DEBUG
if (inbuf->inputstate & INS_command)
dev_err(cs->dev,
"received <DLE> 'X' in command mode\n");
#endif
inbuf->inputstate |=
INS_command | INS_DLE_command;
break;
case '.': /*end of command*/
#ifdef CONFIG_GIGASET_DEBUG
if (!(inbuf->inputstate & INS_command))
dev_err(cs->dev,
"received <DLE> '.' in hdlc mode\n");
#endif
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;
}
}
}
gig_dbg(DEBUG_INTR, "setting head to %u", head);
inbuf->head = head;
}
}
EXPORT_SYMBOL_GPL(gigaset_m10x_input);
/* == data output ========================================================== */
/* Encoding of a PPP packet into an octet stuffed HDLC frame
* with FCS, opening and closing flags.
* parameters:
* skb skb containing original packet (freed upon return)
* head number of headroom bytes to allocate in result skb
* tail number of tailroom bytes to allocate in result skb
* Return value:
* pointer to newly allocated skb containing the result frame
*/
static struct sk_buff *HDLC_Encode(struct sk_buff *skb, int head, int tail)
{
struct sk_buff *hdlc_skb;
__u16 fcs;
unsigned char c;
unsigned char *cp;
int len;
unsigned int stuf_cnt;
stuf_cnt = 0;
fcs = PPP_INITFCS;
cp = skb->data;
len = skb->len;
while (len--) {
if (muststuff(*cp))
stuf_cnt++;
fcs = crc_ccitt_byte(fcs, *cp++);
}
fcs ^= 0xffff; /* complement */
/* size of new buffer: original size + number of stuffing bytes
* + 2 bytes FCS + 2 stuffing bytes for FCS (if needed) + 2 flag bytes
*/
hdlc_skb = dev_alloc_skb(skb->len + stuf_cnt + 6 + tail + head);
if (!hdlc_skb) {
dev_kfree_skb(skb);
return NULL;
}
skb_reserve(hdlc_skb, head);
/* Copy acknowledge request into new skb */
memcpy(hdlc_skb->head, skb->head, 2);
/* Add flag sequence in front of everything.. */
*(skb_put(hdlc_skb, 1)) = PPP_FLAG;
/* Perform byte stuffing while copying data. */
while (skb->len--) {
if (muststuff(*skb->data)) {
*(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
*(skb_put(hdlc_skb, 1)) = (*skb->data++) ^ PPP_TRANS;
} else
*(skb_put(hdlc_skb, 1)) = *skb->data++;
}
/* Finally add FCS (byte stuffed) and flag sequence */
c = (fcs & 0x00ff); /* least significant byte first */
if (muststuff(c)) {
*(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
c ^= PPP_TRANS;
}
*(skb_put(hdlc_skb, 1)) = c;
c = ((fcs >> 8) & 0x00ff);
if (muststuff(c)) {
*(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
c ^= PPP_TRANS;
}
*(skb_put(hdlc_skb, 1)) = c;
*(skb_put(hdlc_skb, 1)) = PPP_FLAG;
dev_kfree_skb(skb);
return hdlc_skb;
}
/* Encoding of a raw packet into an octet stuffed bit inverted frame
* parameters:
* skb skb containing original packet (freed upon return)
* head number of headroom bytes to allocate in result skb
* tail number of tailroom bytes to allocate in result skb
* Return value:
* pointer to newly allocated skb containing the result frame
*/
static struct sk_buff *iraw_encode(struct sk_buff *skb, int head, int tail)
{
struct sk_buff *iraw_skb;
unsigned char c;
unsigned char *cp;
int len;
/* worst case: every byte must be stuffed */
iraw_skb = dev_alloc_skb(2*skb->len + tail + head);
if (!iraw_skb) {
dev_kfree_skb(skb);
return NULL;
}
skb_reserve(iraw_skb, head);
cp = skb->data;
len = skb->len;
while (len--) {
c = bitrev8(*cp++);
if (c == DLE_FLAG)
*(skb_put(iraw_skb, 1)) = c;
*(skb_put(iraw_skb, 1)) = c;
}
dev_kfree_skb(skb);
return iraw_skb;
}
/* gigaset_send_skb
* called by common.c to queue an skb for sending
* and start transmission if necessary
* parameters:
* B Channel control structure
* skb
* Return value:
* number of bytes accepted for sending
* (skb->len if ok, 0 if out of buffer space)
* or error code (< 0, eg. -EINVAL)
*/
int gigaset_m10x_send_skb(struct bc_state *bcs, struct sk_buff *skb)
{
unsigned len = skb->len;
unsigned long flags;
if (bcs->proto2 == ISDN_PROTO_L2_HDLC)
skb = HDLC_Encode(skb, HW_HDR_LEN, 0);
else
skb = iraw_encode(skb, HW_HDR_LEN, 0);
if (!skb) {
err("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);
return len; /* ok so far */
}
EXPORT_SYMBOL_GPL(gigaset_m10x_send_skb);
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