diff options
Diffstat (limited to 'drivers/isdn/gigaset/asyncdata.c')
| -rw-r--r-- | drivers/isdn/gigaset/asyncdata.c | 609 |
1 files changed, 609 insertions, 0 deletions
diff --git a/drivers/isdn/gigaset/asyncdata.c b/drivers/isdn/gigaset/asyncdata.c new file mode 100644 index 000000000..c90dca5ab --- /dev/null +++ b/drivers/isdn/gigaset/asyncdata.c @@ -0,0 +1,609 @@ +/* + * 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> +#include <linux/export.h> + +/* check if byte must be stuffed/escaped + * I'm not sure which data should be encoded. + * Therefore I will go the hard way and encode 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 + * (mstate != MS_LOCKED && (inputstate & INS_command)) + * Append received bytes to the command response buffer and forward them + * line by line to the response handler. Exit whenever a mode/state change + * might have occurred. + * Note: Received lines may be terminated by CR, LF, or CR LF, which will be + * removed before passing the line to the response handler. + * Return value: + * number of processed bytes + */ +static unsigned cmd_loop(unsigned numbytes, struct inbuf_t *inbuf) +{ + unsigned char *src = inbuf->data + inbuf->head; + struct cardstate *cs = inbuf->cs; + unsigned cbytes = cs->cbytes; + unsigned procbytes = 0; + unsigned char c; + + while (procbytes < numbytes) { + c = *src++; + procbytes++; + + switch (c) { + case '\n': + if (cbytes == 0 && cs->respdata[0] == '\r') { + /* collapse LF with preceding CR */ + cs->respdata[0] = 0; + break; + } + /* --v-- fall through --v-- */ + case '\r': + /* end of message line, pass to response handler */ + if (cbytes >= MAX_RESP_SIZE) { + dev_warn(cs->dev, "response too large (%d)\n", + cbytes); + cbytes = MAX_RESP_SIZE; + } + cs->cbytes = cbytes; + gigaset_dbg_buffer(DEBUG_TRANSCMD, "received response", + cbytes, cs->respdata); + gigaset_handle_modem_response(cs); + cbytes = 0; + + /* store EOL byte for CRLF collapsing */ + cs->respdata[0] = c; + + /* cs->dle may have changed */ + if (cs->dle && !(inbuf->inputstate & INS_DLE_command)) + inbuf->inputstate &= ~INS_command; + + /* return for reevaluating state */ + goto exit; + + case DLE_FLAG: + if (inbuf->inputstate & INS_DLE_char) { + /* quoted DLE: clear quote flag */ + inbuf->inputstate &= ~INS_DLE_char; + } else if (cs->dle || + (inbuf->inputstate & INS_DLE_command)) { + /* DLE escape, pass up for handling */ + inbuf->inputstate |= INS_DLE_char; + goto exit; + } + /* quoted or not in DLE mode: treat as regular data */ + /* --v-- fall through --v-- */ + default: + /* append to line buffer if possible */ + if (cbytes < MAX_RESP_SIZE) + cs->respdata[cbytes] = c; + cbytes++; + } + } +exit: + cs->cbytes = cbytes; + return procbytes; +} + +/* process a block of received bytes in lock mode + * All received bytes are passed unmodified to the tty i/f. + * Return value: + * number of processed bytes + */ +static unsigned lock_loop(unsigned numbytes, struct inbuf_t *inbuf) +{ + unsigned char *src = inbuf->data + inbuf->head; + + gigaset_dbg_buffer(DEBUG_LOCKCMD, "received response", numbytes, src); + gigaset_if_receive(inbuf->cs, src, numbytes); + return numbytes; +} + +/* process a block of received bytes in HDLC data mode + * (mstate != MS_LOCKED && !(inputstate & INS_command) && proto2 == L2_HDLC) + * 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 + */ +static unsigned hdlc_loop(unsigned numbytes, struct inbuf_t *inbuf) +{ + struct cardstate *cs = inbuf->cs; + struct bc_state *bcs = cs->bcs; + int inputstate = bcs->inputstate; + __u16 fcs = bcs->rx_fcs; + struct sk_buff *skb = bcs->rx_skb; + unsigned char *src = inbuf->data + inbuf->head; + unsigned procbytes = 0; + unsigned char c; + + if (inputstate & INS_byte_stuff) { + if (!numbytes) + return 0; + inputstate &= ~INS_byte_stuff; + goto byte_stuff; + } + + while (procbytes < numbytes) { + c = *src++; + procbytes++; + if (c == DLE_FLAG) { + if (inputstate & INS_DLE_char) { + /* quoted DLE: clear quote flag */ + inputstate &= ~INS_DLE_char; + } else if (cs->dle || (inputstate & INS_DLE_command)) { + /* DLE escape, pass up for handling */ + inputstate |= INS_DLE_char; + break; + } + } + + if (c == PPP_ESCAPE) { + /* byte stuffing indicator: pull in next byte */ + if (procbytes >= numbytes) { + /* end of buffer, save for later processing */ + inputstate |= INS_byte_stuff; + break; + } +byte_stuff: + c = *src++; + procbytes++; + if (c == DLE_FLAG) { + if (inputstate & INS_DLE_char) { + /* quoted DLE: clear quote flag */ + inputstate &= ~INS_DLE_char; + } else if (cs->dle || + (inputstate & INS_DLE_command)) { + /* DLE escape, pass up for handling */ + inputstate |= + INS_DLE_char | INS_byte_stuff; + break; + } + } + c ^= PPP_TRANS; +#ifdef CONFIG_GIGASET_DEBUG + if (!muststuff(c)) + gig_dbg(DEBUG_HDLC, "byte stuffed: 0x%02x", c); +#endif + } else if (c == PPP_FLAG) { + /* end of frame: process content if any */ + if (inputstate & INS_have_data) { + gig_dbg(DEBUG_HDLC, + "7e----------------------------"); + + /* check and pass received frame */ + if (!skb) { + /* skipped frame */ + gigaset_isdn_rcv_err(bcs); + } else if (skb->len < 2) { + /* frame too short for FCS */ + dev_warn(cs->dev, + "short frame (%d)\n", + skb->len); + gigaset_isdn_rcv_err(bcs); + dev_kfree_skb_any(skb); + } else if (fcs != PPP_GOODFCS) { + /* frame check error */ + dev_err(cs->dev, + "Checksum failed, %u bytes corrupted!\n", + skb->len); + gigaset_isdn_rcv_err(bcs); + dev_kfree_skb_any(skb); + } else { + /* good frame */ + __skb_trim(skb, skb->len - 2); + gigaset_skb_rcvd(bcs, skb); + } + + /* prepare reception of next frame */ + inputstate &= ~INS_have_data; + skb = gigaset_new_rx_skb(bcs); + } else { + /* empty frame (7E 7E) */ +#ifdef CONFIG_GIGASET_DEBUG + ++bcs->emptycount; +#endif + if (!skb) { + /* skipped (?) */ + gigaset_isdn_rcv_err(bcs); + skb = gigaset_new_rx_skb(bcs); + } + } + + fcs = PPP_INITFCS; + continue; +#ifdef CONFIG_GIGASET_DEBUG + } else if (muststuff(c)) { + /* Should not happen. Possible after ZDLE=1<CR><LF>. */ + gig_dbg(DEBUG_HDLC, "not byte stuffed: 0x%02x", c); +#endif + } + + /* regular data byte, append to skb */ +#ifdef CONFIG_GIGASET_DEBUG + if (!(inputstate & INS_have_data)) { + gig_dbg(DEBUG_HDLC, "7e (%d x) ================", + bcs->emptycount); + bcs->emptycount = 0; + } +#endif + inputstate |= INS_have_data; + if (skb) { + if (skb->len >= bcs->rx_bufsize) { + dev_warn(cs->dev, "received packet too long\n"); + dev_kfree_skb_any(skb); + /* skip remainder of packet */ + bcs->rx_skb = skb = NULL; + } else { + *__skb_put(skb, 1) = c; + fcs = crc_ccitt_byte(fcs, c); + } + } + } + + bcs->inputstate = inputstate; + bcs->rx_fcs = fcs; + return procbytes; +} + +/* process a block of received bytes in transparent data mode + * (mstate != MS_LOCKED && !(inputstate & INS_command) && proto2 != L2_HDLC) + * 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 + */ +static unsigned iraw_loop(unsigned numbytes, struct inbuf_t *inbuf) +{ + struct cardstate *cs = inbuf->cs; + struct bc_state *bcs = cs->bcs; + int inputstate = bcs->inputstate; + struct sk_buff *skb = bcs->rx_skb; + unsigned char *src = inbuf->data + inbuf->head; + unsigned procbytes = 0; + unsigned char c; + + if (!skb) { + /* skip this block */ + gigaset_new_rx_skb(bcs); + return numbytes; + } + + while (procbytes < numbytes && skb->len < bcs->rx_bufsize) { + c = *src++; + procbytes++; + + if (c == DLE_FLAG) { + if (inputstate & INS_DLE_char) { + /* quoted DLE: clear quote flag */ + inputstate &= ~INS_DLE_char; + } else if (cs->dle || (inputstate & INS_DLE_command)) { + /* DLE escape, pass up for handling */ + inputstate |= INS_DLE_char; + break; + } + } + + /* regular data byte: append to current skb */ + inputstate |= INS_have_data; + *__skb_put(skb, 1) = bitrev8(c); + } + + /* pass data up */ + if (inputstate & INS_have_data) { + gigaset_skb_rcvd(bcs, skb); + inputstate &= ~INS_have_data; + gigaset_new_rx_skb(bcs); + } + + bcs->inputstate = inputstate; + return procbytes; +} + +/* process DLE escapes + * Called whenever a DLE sequence might be encountered in the input stream. + * Either processes the entire DLE sequence or, if that isn't possible, + * notes the fact that an initial DLE has been received in the INS_DLE_char + * inputstate flag and resumes processing of the sequence on the next call. + */ +static void handle_dle(struct inbuf_t *inbuf) +{ + struct cardstate *cs = inbuf->cs; + + if (cs->mstate == MS_LOCKED) + return; /* no DLE processing in lock mode */ + + if (!(inbuf->inputstate & INS_DLE_char)) { + /* no DLE pending */ + if (inbuf->data[inbuf->head] == DLE_FLAG && + (cs->dle || inbuf->inputstate & INS_DLE_command)) { + /* start of DLE sequence */ + inbuf->head++; + if (inbuf->head == inbuf->tail || + inbuf->head == RBUFSIZE) { + /* end of buffer, save for later processing */ + inbuf->inputstate |= INS_DLE_char; + return; + } + } else { + /* regular data byte */ + return; + } + } + + /* consume pending DLE */ + inbuf->inputstate &= ~INS_DLE_char; + + switch (inbuf->data[inbuf->head]) { + case 'X': /* begin of event message */ + if (inbuf->inputstate & INS_command) + dev_notice(cs->dev, + "received <DLE>X in command mode\n"); + inbuf->inputstate |= INS_command | INS_DLE_command; + inbuf->head++; /* byte consumed */ + break; + case '.': /* end of event message */ + if (!(inbuf->inputstate & INS_DLE_command)) + dev_notice(cs->dev, + "received <DLE>. without <DLE>X\n"); + inbuf->inputstate &= ~INS_DLE_command; + /* return to data mode if in DLE mode */ + if (cs->dle) + inbuf->inputstate &= ~INS_command; + inbuf->head++; /* byte consumed */ + break; + case DLE_FLAG: /* DLE in data stream */ + /* mark as quoted */ + inbuf->inputstate |= INS_DLE_char; + if (!(cs->dle || inbuf->inputstate & INS_DLE_command)) + dev_notice(cs->dev, + "received <DLE><DLE> not in DLE mode\n"); + break; /* quoted byte left in buffer */ + default: + dev_notice(cs->dev, "received <DLE><%02x>\n", + inbuf->data[inbuf->head]); + /* quoted byte left in buffer */ + } +} + +/** + * gigaset_m10x_input() - process a block of data received from the device + * @inbuf: received data and device descriptor structure. + * + * Called by hardware module {ser,usb}_gigaset with a block of received + * bytes. Separates the bytes received over the serial data channel into + * user data and command replies (locked/unlocked) according to the + * current state of the interface. + */ +void gigaset_m10x_input(struct inbuf_t *inbuf) +{ + struct cardstate *cs = inbuf->cs; + unsigned numbytes, procbytes; + + gig_dbg(DEBUG_INTR, "buffer state: %u -> %u", inbuf->head, inbuf->tail); + + while (inbuf->head != inbuf->tail) { + /* check for DLE escape */ + handle_dle(inbuf); + + /* process a contiguous block of bytes */ + numbytes = (inbuf->head > inbuf->tail ? + RBUFSIZE : inbuf->tail) - inbuf->head; + gig_dbg(DEBUG_INTR, "processing %u bytes", numbytes); + /* + * numbytes may be 0 if handle_dle() ate the last byte. + * This does no harm, *_loop() will just return 0 immediately. + */ + + if (cs->mstate == MS_LOCKED) + procbytes = lock_loop(numbytes, inbuf); + else if (inbuf->inputstate & INS_command) + procbytes = cmd_loop(numbytes, inbuf); + else if (cs->bcs->proto2 == L2_HDLC) + procbytes = hdlc_loop(numbytes, inbuf); + else + procbytes = iraw_loop(numbytes, inbuf); + inbuf->head += procbytes; + + /* check for buffer wraparound */ + if (inbuf->head >= RBUFSIZE) + inbuf->head = 0; + + gig_dbg(DEBUG_INTR, "head set to %u", inbuf->head); + } +} +EXPORT_SYMBOL_GPL(gigaset_m10x_input); + + +/* == data output ========================================================== */ + +/* + * Encode a data packet into an octet stuffed HDLC frame with FCS, + * opening and closing flags, preserving headroom data. + * parameters: + * skb skb containing original packet (freed upon return) + * Return value: + * pointer to newly allocated skb containing the result frame + * and the original link layer header, NULL on error + */ +static struct sk_buff *HDLC_Encode(struct sk_buff *skb) +{ + 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 + * + room for link layer header + */ + hdlc_skb = dev_alloc_skb(skb->len + stuf_cnt + 6 + skb->mac_len); + if (!hdlc_skb) { + dev_kfree_skb_any(skb); + return NULL; + } + + /* Copy link layer header into new skb */ + skb_reset_mac_header(hdlc_skb); + skb_reserve(hdlc_skb, skb->mac_len); + memcpy(skb_mac_header(hdlc_skb), skb_mac_header(skb), skb->mac_len); + hdlc_skb->mac_len = skb->mac_len; + + /* 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_any(skb); + return hdlc_skb; +} + +/* + * Encode a data packet into an octet stuffed raw bit inverted frame, + * preserving headroom data. + * parameters: + * skb skb containing original packet (freed upon return) + * Return value: + * pointer to newly allocated skb containing the result frame + * and the original link layer header, NULL on error + */ +static struct sk_buff *iraw_encode(struct sk_buff *skb) +{ + struct sk_buff *iraw_skb; + unsigned char c; + unsigned char *cp; + int len; + + /* size of new buffer (worst case = every byte must be stuffed): + * 2 * original size + room for link layer header + */ + iraw_skb = dev_alloc_skb(2 * skb->len + skb->mac_len); + if (!iraw_skb) { + dev_kfree_skb_any(skb); + return NULL; + } + + /* copy link layer header into new skb */ + skb_reset_mac_header(iraw_skb); + skb_reserve(iraw_skb, skb->mac_len); + memcpy(skb_mac_header(iraw_skb), skb_mac_header(skb), skb->mac_len); + iraw_skb->mac_len = skb->mac_len; + + /* copy and stuff data */ + 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_any(skb); + return iraw_skb; +} + +/** + * gigaset_m10x_send_skb() - queue an skb for sending + * @bcs: B channel descriptor structure. + * @skb: data to send. + * + * Called by LL to encode and queue an skb for sending, and start + * transmission if necessary. + * Once the payload data has been transmitted completely, gigaset_skb_sent() + * will be called with the skb's link layer header preserved. + * + * Return value: + * number of bytes accepted for sending (skb->len) if ok, + * error code < 0 (eg. -ENOMEM) on error + */ +int gigaset_m10x_send_skb(struct bc_state *bcs, struct sk_buff *skb) +{ + struct cardstate *cs = bcs->cs; + unsigned len = skb->len; + unsigned long flags; + + if (bcs->proto2 == L2_HDLC) + skb = HDLC_Encode(skb); + else + skb = iraw_encode(skb); + if (!skb) { + dev_err(cs->dev, + "unable to allocate memory for encoding!\n"); + return -ENOMEM; + } + + skb_queue_tail(&bcs->squeue, skb); + spin_lock_irqsave(&cs->lock, flags); + if (cs->connected) + tasklet_schedule(&cs->write_tasklet); + spin_unlock_irqrestore(&cs->lock, flags); + + return len; /* ok so far */ +} +EXPORT_SYMBOL_GPL(gigaset_m10x_send_skb); |