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-rw-r--r--net/irda/wrapper.c492
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diff --git a/net/irda/wrapper.c b/net/irda/wrapper.c
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+++ /dev/null
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-/*********************************************************************
- *
- * Filename: wrapper.c
- * Version: 1.2
- * Description: IrDA SIR async wrapper layer
- * Status: Stable
- * Author: Dag Brattli <dagb@cs.uit.no>
- * Created at: Mon Aug 4 20:40:53 1997
- * Modified at: Fri Jan 28 13:21:09 2000
- * Modified by: Dag Brattli <dagb@cs.uit.no>
- * Modified at: Fri May 28 3:11 CST 1999
- * Modified by: Horst von Brand <vonbrand@sleipnir.valparaiso.cl>
- *
- * Copyright (c) 1998-2000 Dag Brattli <dagb@cs.uit.no>,
- * All Rights Reserved.
- * Copyright (c) 2000-2002 Jean Tourrilhes <jt@hpl.hp.com>
- *
- * 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.
- *
- * Neither Dag Brattli nor University of Tromsø admit liability nor
- * provide warranty for any of this software. This material is
- * provided "AS-IS" and at no charge.
- *
- ********************************************************************/
-
-#include <linux/skbuff.h>
-#include <linux/string.h>
-#include <linux/module.h>
-#include <asm/byteorder.h>
-
-#include <net/irda/irda.h>
-#include <net/irda/wrapper.h>
-#include <net/irda/crc.h>
-#include <net/irda/irlap.h>
-#include <net/irda/irlap_frame.h>
-#include <net/irda/irda_device.h>
-
-/************************** FRAME WRAPPING **************************/
-/*
- * Unwrap and unstuff SIR frames
- *
- * Note : at FIR and MIR, HDLC framing is used and usually handled
- * by the controller, so we come here only for SIR... Jean II
- */
-
-/*
- * Function stuff_byte (byte, buf)
- *
- * Byte stuff one single byte and put the result in buffer pointed to by
- * buf. The buffer must at all times be able to have two bytes inserted.
- *
- * This is in a tight loop, better inline it, so need to be prior to callers.
- * (2000 bytes on P6 200MHz, non-inlined ~370us, inline ~170us) - Jean II
- */
-static inline int stuff_byte(__u8 byte, __u8 *buf)
-{
- switch (byte) {
- case BOF: /* FALLTHROUGH */
- case EOF: /* FALLTHROUGH */
- case CE:
- /* Insert transparently coded */
- buf[0] = CE; /* Send link escape */
- buf[1] = byte^IRDA_TRANS; /* Complement bit 5 */
- return 2;
- /* break; */
- default:
- /* Non-special value, no transparency required */
- buf[0] = byte;
- return 1;
- /* break; */
- }
-}
-
-/*
- * Function async_wrap (skb, *tx_buff, buffsize)
- *
- * Makes a new buffer with wrapping and stuffing, should check that
- * we don't get tx buffer overflow.
- */
-int async_wrap_skb(struct sk_buff *skb, __u8 *tx_buff, int buffsize)
-{
- struct irda_skb_cb *cb = (struct irda_skb_cb *) skb->cb;
- int xbofs;
- int i;
- int n;
- union {
- __u16 value;
- __u8 bytes[2];
- } fcs;
-
- /* Initialize variables */
- fcs.value = INIT_FCS;
- n = 0;
-
- /*
- * Send XBOF's for required min. turn time and for the negotiated
- * additional XBOFS
- */
-
- if (cb->magic != LAP_MAGIC) {
- /*
- * This will happen for all frames sent from user-space.
- * Nothing to worry about, but we set the default number of
- * BOF's
- */
- pr_debug("%s(), wrong magic in skb!\n", __func__);
- xbofs = 10;
- } else
- xbofs = cb->xbofs + cb->xbofs_delay;
-
- pr_debug("%s(), xbofs=%d\n", __func__, xbofs);
-
- /* Check that we never use more than 115 + 48 xbofs */
- if (xbofs > 163) {
- pr_debug("%s(), too many xbofs (%d)\n", __func__,
- xbofs);
- xbofs = 163;
- }
-
- memset(tx_buff + n, XBOF, xbofs);
- n += xbofs;
-
- /* Start of packet character BOF */
- tx_buff[n++] = BOF;
-
- /* Insert frame and calc CRC */
- for (i=0; i < skb->len; i++) {
- /*
- * Check for the possibility of tx buffer overflow. We use
- * bufsize-5 since the maximum number of bytes that can be
- * transmitted after this point is 5.
- */
- if(n >= (buffsize-5)) {
- net_err_ratelimited("%s(), tx buffer overflow (n=%d)\n",
- __func__, n);
- return n;
- }
-
- n += stuff_byte(skb->data[i], tx_buff+n);
- fcs.value = irda_fcs(fcs.value, skb->data[i]);
- }
-
- /* Insert CRC in little endian format (LSB first) */
- fcs.value = ~fcs.value;
-#ifdef __LITTLE_ENDIAN
- n += stuff_byte(fcs.bytes[0], tx_buff+n);
- n += stuff_byte(fcs.bytes[1], tx_buff+n);
-#else /* ifdef __BIG_ENDIAN */
- n += stuff_byte(fcs.bytes[1], tx_buff+n);
- n += stuff_byte(fcs.bytes[0], tx_buff+n);
-#endif
- tx_buff[n++] = EOF;
-
- return n;
-}
-EXPORT_SYMBOL(async_wrap_skb);
-
-/************************* FRAME UNWRAPPING *************************/
-/*
- * Unwrap and unstuff SIR frames
- *
- * Complete rewrite by Jean II :
- * More inline, faster, more compact, more logical. Jean II
- * (16 bytes on P6 200MHz, old 5 to 7 us, new 4 to 6 us)
- * (24 bytes on P6 200MHz, old 9 to 10 us, new 7 to 8 us)
- * (for reference, 115200 b/s is 1 byte every 69 us)
- * And reduce wrapper.o by ~900B in the process ;-)
- *
- * Then, we have the addition of ZeroCopy, which is optional
- * (i.e. the driver must initiate it) and improve final processing.
- * (2005 B frame + EOF on P6 200MHz, without 30 to 50 us, with 10 to 25 us)
- *
- * Note : at FIR and MIR, HDLC framing is used and usually handled
- * by the controller, so we come here only for SIR... Jean II
- */
-
-/*
- * We can also choose where we want to do the CRC calculation. We can
- * do it "inline", as we receive the bytes, or "postponed", when
- * receiving the End-Of-Frame.
- * (16 bytes on P6 200MHz, inlined 4 to 6 us, postponed 4 to 5 us)
- * (24 bytes on P6 200MHz, inlined 7 to 8 us, postponed 5 to 7 us)
- * With ZeroCopy :
- * (2005 B frame on P6 200MHz, inlined 10 to 25 us, postponed 140 to 180 us)
- * Without ZeroCopy :
- * (2005 B frame on P6 200MHz, inlined 30 to 50 us, postponed 150 to 180 us)
- * (Note : numbers taken with irq disabled)
- *
- * From those numbers, it's not clear which is the best strategy, because
- * we end up running through a lot of data one way or another (i.e. cache
- * misses). I personally prefer to avoid the huge latency spike of the
- * "postponed" solution, because it come just at the time when we have
- * lot's of protocol processing to do and it will hurt our ability to
- * reach low link turnaround times... Jean II
- */
-//#define POSTPONE_RX_CRC
-
-/*
- * Function async_bump (buf, len, stats)
- *
- * Got a frame, make a copy of it, and pass it up the stack! We can try
- * to inline it since it's only called from state_inside_frame
- */
-static inline void
-async_bump(struct net_device *dev,
- struct net_device_stats *stats,
- iobuff_t *rx_buff)
-{
- struct sk_buff *newskb;
- struct sk_buff *dataskb;
- int docopy;
-
- /* Check if we need to copy the data to a new skb or not.
- * If the driver doesn't use ZeroCopy Rx, we have to do it.
- * With ZeroCopy Rx, the rx_buff already point to a valid
- * skb. But, if the frame is small, it is more efficient to
- * copy it to save memory (copy will be fast anyway - that's
- * called Rx-copy-break). Jean II */
- docopy = ((rx_buff->skb == NULL) ||
- (rx_buff->len < IRDA_RX_COPY_THRESHOLD));
-
- /* Allocate a new skb */
- newskb = dev_alloc_skb(docopy ? rx_buff->len + 1 : rx_buff->truesize);
- if (!newskb) {
- stats->rx_dropped++;
- /* We could deliver the current skb if doing ZeroCopy Rx,
- * but this would stall the Rx path. Better drop the
- * packet... Jean II */
- return;
- }
-
- /* Align IP header to 20 bytes (i.e. increase skb->data)
- * Note this is only useful with IrLAN, as PPP has a variable
- * header size (2 or 1 bytes) - Jean II */
- skb_reserve(newskb, 1);
-
- if(docopy) {
- /* Copy data without CRC (length already checked) */
- skb_copy_to_linear_data(newskb, rx_buff->data,
- rx_buff->len - 2);
- /* Deliver this skb */
- dataskb = newskb;
- } else {
- /* We are using ZeroCopy. Deliver old skb */
- dataskb = rx_buff->skb;
- /* And hook the new skb to the rx_buff */
- rx_buff->skb = newskb;
- rx_buff->head = newskb->data; /* NOT newskb->head */
- //printk(KERN_DEBUG "ZeroCopy : len = %d, dataskb = %p, newskb = %p\n", rx_buff->len, dataskb, newskb);
- }
-
- /* Set proper length on skb (without CRC) */
- skb_put(dataskb, rx_buff->len - 2);
-
- /* Feed it to IrLAP layer */
- dataskb->dev = dev;
- skb_reset_mac_header(dataskb);
- dataskb->protocol = htons(ETH_P_IRDA);
-
- netif_rx(dataskb);
-
- stats->rx_packets++;
- stats->rx_bytes += rx_buff->len;
-
- /* Clean up rx_buff (redundant with async_unwrap_bof() ???) */
- rx_buff->data = rx_buff->head;
- rx_buff->len = 0;
-}
-
-/*
- * Function async_unwrap_bof(dev, byte)
- *
- * Handle Beginning Of Frame character received within a frame
- *
- */
-static inline void
-async_unwrap_bof(struct net_device *dev,
- struct net_device_stats *stats,
- iobuff_t *rx_buff, __u8 byte)
-{
- switch(rx_buff->state) {
- case LINK_ESCAPE:
- case INSIDE_FRAME:
- /* Not supposed to happen, the previous frame is not
- * finished - Jean II */
- pr_debug("%s(), Discarding incomplete frame\n",
- __func__);
- stats->rx_errors++;
- stats->rx_missed_errors++;
- irda_device_set_media_busy(dev, TRUE);
- break;
-
- case OUTSIDE_FRAME:
- case BEGIN_FRAME:
- default:
- /* We may receive multiple BOF at the start of frame */
- break;
- }
-
- /* Now receiving frame */
- rx_buff->state = BEGIN_FRAME;
- rx_buff->in_frame = TRUE;
-
- /* Time to initialize receive buffer */
- rx_buff->data = rx_buff->head;
- rx_buff->len = 0;
- rx_buff->fcs = INIT_FCS;
-}
-
-/*
- * Function async_unwrap_eof(dev, byte)
- *
- * Handle End Of Frame character received within a frame
- *
- */
-static inline void
-async_unwrap_eof(struct net_device *dev,
- struct net_device_stats *stats,
- iobuff_t *rx_buff, __u8 byte)
-{
-#ifdef POSTPONE_RX_CRC
- int i;
-#endif
-
- switch(rx_buff->state) {
- case OUTSIDE_FRAME:
- /* Probably missed the BOF */
- stats->rx_errors++;
- stats->rx_missed_errors++;
- irda_device_set_media_busy(dev, TRUE);
- break;
-
- case BEGIN_FRAME:
- case LINK_ESCAPE:
- case INSIDE_FRAME:
- default:
- /* Note : in the case of BEGIN_FRAME and LINK_ESCAPE,
- * the fcs will most likely not match and generate an
- * error, as expected - Jean II */
- rx_buff->state = OUTSIDE_FRAME;
- rx_buff->in_frame = FALSE;
-
-#ifdef POSTPONE_RX_CRC
- /* If we haven't done the CRC as we receive bytes, we
- * must do it now... Jean II */
- for(i = 0; i < rx_buff->len; i++)
- rx_buff->fcs = irda_fcs(rx_buff->fcs,
- rx_buff->data[i]);
-#endif
-
- /* Test FCS and signal success if the frame is good */
- if (rx_buff->fcs == GOOD_FCS) {
- /* Deliver frame */
- async_bump(dev, stats, rx_buff);
- break;
- } else {
- /* Wrong CRC, discard frame! */
- irda_device_set_media_busy(dev, TRUE);
-
- pr_debug("%s(), crc error\n", __func__);
- stats->rx_errors++;
- stats->rx_crc_errors++;
- }
- break;
- }
-}
-
-/*
- * Function async_unwrap_ce(dev, byte)
- *
- * Handle Character Escape character received within a frame
- *
- */
-static inline void
-async_unwrap_ce(struct net_device *dev,
- struct net_device_stats *stats,
- iobuff_t *rx_buff, __u8 byte)
-{
- switch(rx_buff->state) {
- case OUTSIDE_FRAME:
- /* Activate carrier sense */
- irda_device_set_media_busy(dev, TRUE);
- break;
-
- case LINK_ESCAPE:
- net_warn_ratelimited("%s: state not defined\n", __func__);
- break;
-
- case BEGIN_FRAME:
- case INSIDE_FRAME:
- default:
- /* Stuffed byte coming */
- rx_buff->state = LINK_ESCAPE;
- break;
- }
-}
-
-/*
- * Function async_unwrap_other(dev, byte)
- *
- * Handle other characters received within a frame
- *
- */
-static inline void
-async_unwrap_other(struct net_device *dev,
- struct net_device_stats *stats,
- iobuff_t *rx_buff, __u8 byte)
-{
- switch(rx_buff->state) {
- /* This is on the critical path, case are ordered by
- * probability (most frequent first) - Jean II */
- case INSIDE_FRAME:
- /* Must be the next byte of the frame */
- if (rx_buff->len < rx_buff->truesize) {
- rx_buff->data[rx_buff->len++] = byte;
-#ifndef POSTPONE_RX_CRC
- rx_buff->fcs = irda_fcs(rx_buff->fcs, byte);
-#endif
- } else {
- pr_debug("%s(), Rx buffer overflow, aborting\n",
- __func__);
- rx_buff->state = OUTSIDE_FRAME;
- }
- break;
-
- case LINK_ESCAPE:
- /*
- * Stuffed char, complement bit 5 of byte
- * following CE, IrLAP p.114
- */
- byte ^= IRDA_TRANS;
- if (rx_buff->len < rx_buff->truesize) {
- rx_buff->data[rx_buff->len++] = byte;
-#ifndef POSTPONE_RX_CRC
- rx_buff->fcs = irda_fcs(rx_buff->fcs, byte);
-#endif
- rx_buff->state = INSIDE_FRAME;
- } else {
- pr_debug("%s(), Rx buffer overflow, aborting\n",
- __func__);
- rx_buff->state = OUTSIDE_FRAME;
- }
- break;
-
- case OUTSIDE_FRAME:
- /* Activate carrier sense */
- if(byte != XBOF)
- irda_device_set_media_busy(dev, TRUE);
- break;
-
- case BEGIN_FRAME:
- default:
- rx_buff->data[rx_buff->len++] = byte;
-#ifndef POSTPONE_RX_CRC
- rx_buff->fcs = irda_fcs(rx_buff->fcs, byte);
-#endif
- rx_buff->state = INSIDE_FRAME;
- break;
- }
-}
-
-/*
- * Function async_unwrap_char (dev, rx_buff, byte)
- *
- * Parse and de-stuff frame received from the IrDA-port
- *
- * This is the main entry point for SIR drivers.
- */
-void async_unwrap_char(struct net_device *dev,
- struct net_device_stats *stats,
- iobuff_t *rx_buff, __u8 byte)
-{
- switch(byte) {
- case CE:
- async_unwrap_ce(dev, stats, rx_buff, byte);
- break;
- case BOF:
- async_unwrap_bof(dev, stats, rx_buff, byte);
- break;
- case EOF:
- async_unwrap_eof(dev, stats, rx_buff, byte);
- break;
- default:
- async_unwrap_other(dev, stats, rx_buff, byte);
- break;
- }
-}
-EXPORT_SYMBOL(async_unwrap_char);
-
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