705 lines
19 KiB
C
705 lines
19 KiB
C
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/* Osmocom Software Defined E1
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*
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* (C) 2018 by Harald Welte <laforge@gnumonks.org>
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*
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* Implements ITU-T Rec. G.704 Section 2.3
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*/
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#include <stdbool.h>
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#include <stdint.h>
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#include <unistd.h>
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#include <errno.h>
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#include <string.h>
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#include <osmocom/core/msgb.h>
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#include <osmocom/core/linuxlist.h>
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#include <osmocom/core/logging.h>
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#include <osmocom/core/fsm.h>
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#include "crc4itu.h"
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#include "osmo_e1f.h"
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#define S(x) (1 << (x))
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/* Frame Alignment Signal (BIT1 may be overwritten with CRC-4) */
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#define G704_E1_FAS 0x1B
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static inline bool is_correct_fas(uint8_t bt) {
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if ((bt & 0x7F) == G704_E1_FAS)
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return true;
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else
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return false;
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}
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/* are we in SMF II (true) or I (false) */
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static inline bool is_smf_II(const struct osmo_e1f_tx_state *tx) {
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if (tx->frame_nr >= 8)
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return true;
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return false;
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}
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static struct osmo_fsm e1_align_fsm;
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static void align_fsm_reset(struct osmo_e1f_instance *e1i);
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static void notify_user(struct osmo_e1f_instance *e1i, enum osmo_e1f_notify_event evt,
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bool present, void *priv)
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{
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if (!e1i->notify_cb)
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return;
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e1i->notify_cb(e1i, evt, present, priv);
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}
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/*! Initialize a (caller-allocated) Osmocom E1 Instance
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* \param[inout] e1i E1 Instance to be initialized
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* \returns 0 on success, negative on error */
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int osmo_e1f_instance_init(struct osmo_e1f_instance *e1i, const char *name, e1_notify_cb cb,
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bool crc4_enabled, void *priv)
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{
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int i;
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e1i->crc4_enabled = crc4_enabled;
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e1i->notify_cb = cb;
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e1i->tx.sa4_sa8 = 0x1f;
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e1i->priv = priv;
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for (i = 1; i < ARRAY_SIZE(e1i->ts); i++) {
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struct osmo_e1f_instance_ts *e1t = &e1i->ts[i];
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e1t->ts_nr = i;
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e1t->inst = e1i;
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INIT_LLIST_HEAD(&e1t->tx.queue);
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e1t->rx.granularity = 256;
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}
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e1i->rx.fi = osmo_fsm_inst_alloc(&e1_align_fsm, NULL, e1i, LOGL_DEBUG, name);
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if (!e1i->rx.fi)
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return -1;
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osmo_e1f_instance_reset(e1i);
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return 0;
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}
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/*! stop E1 timeslot; release any pending rx/tx buffers
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* \param[in] e1t Timeslot which we are to stop, disable and release buffers */
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void osmo_e1f_ts_reset(struct osmo_e1f_instance_ts *e1t)
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{
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e1t->tx.underruns = 0;
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msgb_queue_free(&e1t->tx.queue);
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e1t->rx.enabled = false;
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msgb_free(e1t->rx.msg);
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e1t->rx.msg = NULL;
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osmo_isdnhdlc_rcv_init(&e1t->rx.hdlc, OSMO_HDLC_F_BITREVERSE);
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//osmo_isdnhdlc_rcv_init(&e1t->rx.hdlc, 0);
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osmo_isdnhdlc_out_init(&e1t->tx.hdlc, 0);
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}
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/*! stop E1 instance; stops all timeslots and releases any pending rx/tx buffers
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* \param[in] e1t E1 instance which we are to stop */
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void osmo_e1f_instance_reset(struct osmo_e1f_instance *e1i)
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{
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int i;
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align_fsm_reset(e1i);
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e1i->tx.remote_alarm = false;
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e1i->tx.crc4_error = false;
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e1i->tx.frame_nr = 0;
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e1i->tx.crc4_last_smf = 0;
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e1i->tx.crc4 = crc4itu_init();
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e1i->rx.frame_nr = 0;
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memset(&e1i->rx.ts0_history, 0, sizeof(e1i->rx.ts0_history));
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e1i->rx.ts0_hist_len = 0;
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e1i->rx.remote_alarm = false;
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e1i->rx.remote_crc4_error = false;
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e1i->rx.num_ts0_in_mframe_search = 0;
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for (i = 1; i < ARRAY_SIZE(e1i->ts); i++) {
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struct osmo_e1f_instance_ts *e1t = &e1i->ts[i];
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osmo_e1f_ts_reset(e1t);
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}
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}
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/*! obtain pointer to TS given by instance + timeslot number
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* \param[in] e1i E1 intance on which we work
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* \param[in] ts_nr E1 timeslot number (1..31)
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* \returns pointer to timeslot; NULL on error */
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struct osmo_e1f_instance_ts *osmo_e1f_instance_ts(struct osmo_e1f_instance *e1i, uint8_t ts_nr)
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{
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if (ts_nr == 0 || ts_nr >= ARRAY_SIZE(e1i->ts))
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return NULL;
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return &e1i->ts[ts_nr];
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}
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/*! configure an E1 timeslot
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* \param[in] e1t Timeslot which we are to configure
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* \param[in] granularity granularity (buffer size) to use on Rx
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* \param[in] enable enable (true) or disalble (false) receiving on this TS
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* \param[in] mode the mode for this timeslot (raw or hdlc)
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* \return 0 on success; negative on error */
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int osmo_e1f_ts_config(struct osmo_e1f_instance_ts *e1t, e1_data_cb cb, unsigned int granularity,
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bool enable, enum osmo_e1f_ts_mode mode)
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{
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e1t->rx.data_cb = cb;
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e1t->rx.enabled = enable;
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e1t->rx.granularity = granularity;
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e1t->mode = mode;
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return 0;
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}
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const struct value_string osmo_e1f_notifv_evt_names[] = {
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{ E1_NTFY_EVT_ALIGN_FRAME, "Aligned to Frame" },
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{ E1_NTFY_EVT_ALIGN_CRC_MFRAME, "Aligned to CRC4-Multiframe" },
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{ E1_NTFY_EVT_CRC_ERROR, "CRC Error detected (local)" },
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{ E1_NTFY_EVT_REMOTE_CRC_ERROR, "CRC Error reported (remote)" },
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{ E1_NTFY_EVT_REMOTE_ALARM, "Remote Alarm condition repoorted" },
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{ 0, NULL }
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};
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/***********************************************************************
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* Transmit Side
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***********************************************************************/
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/*! Enqueue a message buffer of to-be-transmitted data for a timeslot
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* \param[in] e1i E1 instance for which to enqueue
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* \param[in] ts_nr Timeslot number on which data is to be transmitted
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* \param[in] msg Message buffer storing the to-be-transmitted data
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* \returns 0 on success; negative in case of error.
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*
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* Ownership of \a msg is transferred from caller into this function, but only
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* in case of successful execution (return 0)!
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*/
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void osmo_e1f_ts_enqueue(struct osmo_e1f_instance_ts *e1t, struct msgb *msg)
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{
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msgb_enqueue(&e1t->tx.queue, msg);
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}
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/* obtain a CRC4 bit for the current frame number */
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static uint8_t e1_pull_crc4_bit(struct osmo_e1f_instance *e1i)
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{
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/* If CRC-4 is disabled, all CRC bits shall be '1' */
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if (e1i->crc4_enabled == 0) {
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return 0x01;
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} else {
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/* CRC is transmitted MSB first */
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switch (e1i->tx.frame_nr % 8) {
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case 0:
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return (e1i->tx.crc4_last_smf >> 3) & 1;
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case 2:
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return (e1i->tx.crc4_last_smf >> 2) & 1;
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case 4:
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return (e1i->tx.crc4_last_smf >> 1) & 1;
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case 6:
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return (e1i->tx.crc4_last_smf >> 0) & 1;
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default:
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OSMO_ASSERT(0);
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}
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}
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}
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/* pull a single to-be-transmitted byte for TS0 */
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static uint8_t e1_pull_ts0(struct osmo_e1f_instance *e1i)
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{
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uint8_t ret = 0;
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/* re-set CRC4 at start of sub-multiframe */
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if (e1i->tx.frame_nr == 0 || e1i->tx.frame_nr == 8) {
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e1i->tx.crc4_last_smf = e1i->tx.crc4;
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e1i->tx.crc4 = 0;
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}
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/* according to Table 5B/G.704 - CRC-4 multiframe structure */
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if ((e1i->tx.frame_nr % 2) == 0) {
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/* FAS */
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ret = G704_E1_FAS | (e1_pull_crc4_bit(e1i) << 7);
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} else {
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switch (e1i->tx.frame_nr) {
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case 1:
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case 3:
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case 7:
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ret = 0x40;
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break;
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case 5:
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case 9:
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case 11:
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ret = 0xC0;
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break;
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case 13:
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case 15:
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ret = 0x40;
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if (!e1i->tx.crc4_error)
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ret |= 0x80;
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break;
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}
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ret |= e1i->tx.sa4_sa8;
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if (e1i->tx.remote_alarm)
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ret |= 0x20;
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}
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/* increment frame number modulo 16 */
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e1i->tx.frame_nr = (e1i->tx.frame_nr + 1) % 16;
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return ret;
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}
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/* pull a single to-be-transmitted byte for TS1..31 */
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static uint8_t e1_pull_tsN(struct osmo_e1f_instance_ts *e1t)
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{
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struct msgb *msg = llist_first_entry_or_null(&e1t->tx.queue, struct msgb, list);
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uint8_t *cur;
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retry:
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/* if there's no message to transmit */
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if (!msg) {
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e1t->tx.underruns++;
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return 0xFF;
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}
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if (msgb_length(msg) <= 0) {
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llist_del(&msg->list);
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msgb_free(msg);
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msg = llist_first_entry_or_null(&e1t->tx.queue, struct msgb, list);
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goto retry;
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}
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cur = msgb_pull(msg, 1);
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return *cur;
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}
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/* update the current in-progress CRC4 value with data from \a out_frame */
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static void e1_tx_update_crc4(struct osmo_e1f_instance *e1i, const uint8_t *out_frame)
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{
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uint8_t ts0;
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ts0 = out_frame[0];
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/* mask off the C bits */
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if (is_correct_fas(ts0))
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ts0 &= 0x7F;
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e1i->tx.crc4 = crc4itu_update(e1i->tx.crc4, &ts0, 1);
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/* add the remaining bytes/bits */
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e1i->tx.crc4 = crc4itu_update(e1i->tx.crc4, out_frame+1, ARRAY_SIZE(e1i->ts)-1);
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}
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/*! Pull one to-be-transmitted E1 frame (256bits) from the E1 instance
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* \param e1i E1 instance for which the frame shall be generated
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* \param[out] out_frame callee-allocated buffer to which function stores 32 bytes
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* \returns 0 on success, negative on error */
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int osmo_e1f_pull_tx_frame(struct osmo_e1f_instance *e1i, uint8_t *out_frame)
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{
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int i;
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if (e1i->tx.ais) {
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memset(out_frame, 0xff, 32);
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return 0;
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}
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/* generate TS0 */
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out_frame[0] = e1_pull_ts0(e1i);
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/* generate TS1..31 */
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for (i = 1; i < ARRAY_SIZE(e1i->ts); i++) {
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struct osmo_e1f_instance_ts *e1t = &e1i->ts[i];
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/* get next to-be-transmitted byte from the TS */
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out_frame[i] = e1_pull_tsN(e1t);
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}
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/* update our CRC4 computation */
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e1_tx_update_crc4(e1i, out_frame);
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return 0;
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}
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/***********************************************************************
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* Receiver Side
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***********************************************************************/
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/* According to Figure 2 / ITU-T G.706 */
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enum e1_align_state {
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/* Frame Alignment Search */
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E1_AS_SEARCH_FRAME,
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/* CRC multiframe alignment search */
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E1_AS_SEARCH_CRC_MFRAME,
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/* monitoring for incorrect frame alignment and error performance using CRC */
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E1_AS_ALIGNED_CRC_MFRAME,
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/* no CRC: just frame alignment loss check */
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E1_AS_ALIGNED_BASIC,
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};
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enum e1_align_event {
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/* received a TS0 octet */
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E1_AE_RX_TS0,
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E1_AE_RESET
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};
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static const struct value_string e1_align_evt_names[] = {
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{ E1_AE_RX_TS0, "E1_AE_RX_TS0" },
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{ E1_AE_RESET, "E1_AE_RESET" },
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{ 0, NULL }
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};
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/* get a TS0 byte from the history. delta 0 == current, delte 1 == previous, ... */
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static uint8_t get_ts0_hist(struct osmo_e1f_instance *e1i, uint8_t delta)
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{
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return e1i->rx.ts0_history[((e1i->rx.frame_nr + 16)-delta) % 16];
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}
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/* ITU-T G.706 Section 4.1.1 */
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static bool frame_alignment_lost(struct osmo_e1f_instance *e1i)
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{
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if (e1i->rx.frame_nr % 2)
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return false;
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/* Frame alignment will be assumed to have been lost when three consecutive incorrect
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* frame alignment signals have been received. */
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if (!is_correct_fas(get_ts0_hist(e1i, 0)) &&
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!is_correct_fas(get_ts0_hist(e1i, 2)) &&
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!is_correct_fas(get_ts0_hist(e1i, 4)))
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return true;
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else
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return false;
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}
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/* ITU-T G.706 Section 4.1.2 */
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static bool frame_alignment_recovered(struct osmo_e1f_instance *e1i)
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{
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/* two consecutive FAS with one non-FAS interspersed */
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if (is_correct_fas(get_ts0_hist(e1i, 0)) &&
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!is_correct_fas(get_ts0_hist(e1i, 1)) &&
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is_correct_fas(get_ts0_hist(e1i, 2)))
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return true;
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else
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return false;
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}
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/* ITU-T G.706 Section 4.2 */
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static bool crc_mframe_alignment_achieved(struct osmo_e1f_instance *e1i)
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{
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/* if current TS0 byte is FAS, we cannot detect alignment */
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if (is_correct_fas(get_ts0_hist(e1i, 0)))
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return false;
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if ((get_ts0_hist(e1i, 0) >> 7) == 1 &&
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(get_ts0_hist(e1i, 2) >> 7) == 1 &&
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(get_ts0_hist(e1i, 4) >> 7) == 0 &&
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(get_ts0_hist(e1i, 6) >> 7) == 1 &&
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(get_ts0_hist(e1i, 8) >> 7) == 0 &&
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(get_ts0_hist(e1i, 10) >> 7) == 0)
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return true;
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else
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return false;
|
||
|
}
|
||
|
|
||
|
/* Get the CRC4 that was received from our Rx TS0 history */
|
||
|
static uint8_t crc4_from_ts0_hist(struct osmo_e1f_instance *e1i, bool smf2)
|
||
|
{
|
||
|
uint8_t crc = 0;
|
||
|
uint8_t offset = 0;
|
||
|
|
||
|
if (smf2)
|
||
|
offset = 8;
|
||
|
|
||
|
crc |= (e1i->rx.ts0_history[0+offset] >> 7) << 3;
|
||
|
crc |= (e1i->rx.ts0_history[2+offset] >> 7) << 2;
|
||
|
crc |= (e1i->rx.ts0_history[4+offset] >> 7) << 1;
|
||
|
crc |= (e1i->rx.ts0_history[6+offset] >> 7) << 0;
|
||
|
|
||
|
return crc;
|
||
|
}
|
||
|
|
||
|
/* update the current in-progress CRC4 value with data from \a rx_frame */
|
||
|
static void e1_rx_update_crc4(struct osmo_e1f_instance *e1i, const uint8_t *rx_frame)
|
||
|
{
|
||
|
uint8_t ts0;
|
||
|
|
||
|
ts0 = rx_frame[0];
|
||
|
/* mask off the C bits */
|
||
|
if (is_correct_fas(ts0))
|
||
|
ts0 &= 0x7F;
|
||
|
e1i->rx.crc4 = crc4itu_update(e1i->rx.crc4, &ts0, 1);
|
||
|
/* add the remaining bytes/bits */
|
||
|
e1i->rx.crc4 = crc4itu_update(e1i->rx.crc4, rx_frame+1, ARRAY_SIZE(e1i->ts)-1);
|
||
|
}
|
||
|
|
||
|
/* FSM State handler */
|
||
|
static void e1_align_search_frame(struct osmo_fsm_inst *fi, uint32_t event, void *data)
|
||
|
{
|
||
|
struct osmo_e1f_instance *e1i = (struct osmo_e1f_instance *) fi->priv;
|
||
|
|
||
|
if (frame_alignment_recovered(e1i)) {
|
||
|
/* if we detected the 2nd FAS, we must be in FN 2 (or at least FN%2=0 */
|
||
|
e1i->rx.frame_nr = 2;
|
||
|
notify_user(e1i, E1_NTFY_EVT_ALIGN_FRAME, true, NULL);
|
||
|
osmo_fsm_inst_state_chg(fi, E1_AS_SEARCH_CRC_MFRAME, 0, 0);
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/* FSM State handler */
|
||
|
static void e1_align_search_crc_mframe(struct osmo_fsm_inst *fi, uint32_t event, void *data)
|
||
|
{
|
||
|
struct osmo_e1f_instance *e1i = (struct osmo_e1f_instance *) fi->priv;
|
||
|
|
||
|
if (crc_mframe_alignment_achieved(e1i)) {
|
||
|
/* if we detected the 6-bit CRC multiframe signal, we must be in FN 11 */
|
||
|
e1i->rx.frame_nr = 11;
|
||
|
/* FIXME: "at least two valid CRC multiframe alignment signals can be located within
|
||
|
* 8 ms, the time separating two CRC multiframe alignment signals being 2 ms or a
|
||
|
* multiple of 2 ms" */
|
||
|
notify_user(e1i, E1_NTFY_EVT_ALIGN_CRC_MFRAME, true, NULL);
|
||
|
osmo_fsm_inst_state_chg(fi, E1_AS_ALIGNED_CRC_MFRAME, 0, 0);
|
||
|
} else {
|
||
|
/* if no mframe alignment is established within 8ms (64 frames), fall back */
|
||
|
if (e1i->rx.num_ts0_in_mframe_search >= 64) {
|
||
|
e1i->rx.num_ts0_in_mframe_search = 0;
|
||
|
osmo_fsm_inst_state_chg(fi, E1_AS_SEARCH_FRAME, 0, 0);
|
||
|
}
|
||
|
e1i->rx.num_ts0_in_mframe_search++;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
static void e1_aligned_common(struct osmo_e1f_instance *e1i)
|
||
|
{
|
||
|
uint8_t inb = get_ts0_hist(e1i, 0);
|
||
|
|
||
|
/* All non-FAS frames contain "A" bit in TS0 */
|
||
|
if (!is_correct_fas(inb & 0x7F)) {
|
||
|
bool old_alarm = e1i->rx.remote_alarm;
|
||
|
/* frame not containing the frame alignment signal */
|
||
|
if (inb & 0x20)
|
||
|
e1i->rx.remote_alarm = true;
|
||
|
else
|
||
|
e1i->rx.remote_alarm = false;
|
||
|
if (old_alarm != e1i->rx.remote_alarm)
|
||
|
notify_user(e1i, E1_NTFY_EVT_REMOTE_ALARM, e1i->rx.remote_alarm, NULL);
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/* FSM State handler */
|
||
|
static void e1_aligned_crc_mframe(struct osmo_fsm_inst *fi, uint32_t event, void *data)
|
||
|
{
|
||
|
struct osmo_e1f_instance *e1i = (struct osmo_e1f_instance *) fi->priv;
|
||
|
|
||
|
if (frame_alignment_lost(e1i)) {
|
||
|
osmo_fsm_inst_state_chg(fi, E1_AS_SEARCH_FRAME, 0, 0);
|
||
|
return;
|
||
|
}
|
||
|
|
||
|
if (e1i->crc4_enabled) {
|
||
|
uint8_t crc_rx;
|
||
|
bool crc4_error;
|
||
|
|
||
|
/* check if we just received a complete CRC4 */
|
||
|
switch (e1i->rx.frame_nr) {
|
||
|
case 7:
|
||
|
case 15:
|
||
|
crc_rx = crc4_from_ts0_hist(e1i, e1i->rx.frame_nr == 15 ? true : false);
|
||
|
if (crc_rx != e1i->rx.crc4_last_smf)
|
||
|
crc4_error = true;
|
||
|
else
|
||
|
crc4_error = false;
|
||
|
if (crc4_error != e1i->tx.crc4_error) {
|
||
|
notify_user(e1i, E1_NTFY_EVT_CRC_ERROR, crc4_error, NULL);
|
||
|
e1i->tx.crc4_error = crc4_error;
|
||
|
}
|
||
|
/* rotate computed CRC4 one further */
|
||
|
e1i->rx.crc4_last_smf = e1i->rx.crc4;
|
||
|
e1i->rx.crc4 = crc4itu_init();
|
||
|
break;
|
||
|
default:
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
/* check if the remote side reports any CRC errors */
|
||
|
switch (e1i->rx.frame_nr) {
|
||
|
case 13:
|
||
|
case 15:
|
||
|
crc4_error = false;
|
||
|
if ((get_ts0_hist(e1i, 0) >> 7) == 0)
|
||
|
crc4_error = true;
|
||
|
if (crc4_error != e1i->rx.remote_crc4_error) {
|
||
|
notify_user(e1i, E1_NTFY_EVT_REMOTE_CRC_ERROR, crc4_error, NULL);
|
||
|
e1i->rx.remote_crc4_error = crc4_error;
|
||
|
}
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
e1_aligned_common(e1i);
|
||
|
}
|
||
|
|
||
|
/* FSM State handler */
|
||
|
static void e1_aligned_basic(struct osmo_fsm_inst *fi, uint32_t event, void *data)
|
||
|
{
|
||
|
struct osmo_e1f_instance *e1i = (struct osmo_e1f_instance *) fi->priv;
|
||
|
|
||
|
if (frame_alignment_lost(e1i)) {
|
||
|
osmo_fsm_inst_state_chg(fi, E1_AS_SEARCH_FRAME, 0, 0);
|
||
|
return;
|
||
|
}
|
||
|
|
||
|
e1_aligned_common(e1i);
|
||
|
}
|
||
|
|
||
|
static const struct osmo_fsm_state e1_align_states[] = {
|
||
|
[E1_AS_SEARCH_FRAME] = {
|
||
|
.name = "SEARCH_FRAME",
|
||
|
.in_event_mask = S(E1_AE_RX_TS0),
|
||
|
.out_state_mask = S(E1_AS_SEARCH_FRAME) |
|
||
|
S(E1_AS_SEARCH_CRC_MFRAME) |
|
||
|
S(E1_AS_ALIGNED_BASIC),
|
||
|
.action = e1_align_search_frame,
|
||
|
},
|
||
|
[E1_AS_SEARCH_CRC_MFRAME] = {
|
||
|
.name = "SEARCH_CRC_MFRAME",
|
||
|
.in_event_mask = S(E1_AE_RX_TS0),
|
||
|
.out_state_mask = S(E1_AS_SEARCH_FRAME) |
|
||
|
S(E1_AS_SEARCH_CRC_MFRAME) |
|
||
|
S(E1_AS_ALIGNED_CRC_MFRAME),
|
||
|
.action = e1_align_search_crc_mframe,
|
||
|
},
|
||
|
[E1_AS_ALIGNED_CRC_MFRAME] = {
|
||
|
.name = "ALIGNED_CRC_MFRAME",
|
||
|
.in_event_mask = S(E1_AE_RX_TS0),
|
||
|
.out_state_mask = S(E1_AS_SEARCH_FRAME) |
|
||
|
S(E1_AS_SEARCH_CRC_MFRAME) |
|
||
|
S(E1_AS_ALIGNED_CRC_MFRAME),
|
||
|
.action = e1_aligned_crc_mframe,
|
||
|
},
|
||
|
[E1_AS_ALIGNED_BASIC] = {
|
||
|
.name = "ALIGNED_BASIC",
|
||
|
.in_event_mask = S(E1_AE_RX_TS0),
|
||
|
.out_state_mask = S(E1_AS_SEARCH_FRAME),
|
||
|
.action = e1_aligned_basic,
|
||
|
},
|
||
|
};
|
||
|
|
||
|
static void e1_allstate(struct osmo_fsm_inst *fi, uint32_t event, void *data)
|
||
|
{
|
||
|
struct osmo_e1f_instance *e1i = (struct osmo_e1f_instance *) fi->priv;
|
||
|
|
||
|
switch (event) {
|
||
|
case E1_AE_RESET:
|
||
|
e1i->rx.num_ts0_in_mframe_search = 0;
|
||
|
osmo_fsm_inst_state_chg(fi, E1_AS_SEARCH_FRAME, 0, 0);
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
static struct osmo_fsm e1_align_fsm = {
|
||
|
.name = "e1-align",
|
||
|
.states = e1_align_states,
|
||
|
.num_states = ARRAY_SIZE(e1_align_states),
|
||
|
.allstate_event_mask = S(E1_AE_RESET),
|
||
|
.allstate_action = e1_allstate,
|
||
|
.log_subsys = DLGLOBAL,
|
||
|
.event_names = e1_align_evt_names,
|
||
|
};
|
||
|
|
||
|
static void align_fsm_reset(struct osmo_e1f_instance *e1i)
|
||
|
{
|
||
|
osmo_fsm_inst_dispatch(e1i->rx.fi, E1_AE_RESET, NULL);
|
||
|
}
|
||
|
|
||
|
static void e1_rx_hist_add(struct osmo_e1f_instance *e1i, uint8_t inb)
|
||
|
{
|
||
|
e1i->rx.ts0_history[e1i->rx.frame_nr] = inb;
|
||
|
if (e1i->rx.ts0_hist_len < 16)
|
||
|
e1i->rx.ts0_hist_len++;
|
||
|
}
|
||
|
|
||
|
static void e1_rx_ts0(struct osmo_e1f_instance *e1i, uint8_t inb)
|
||
|
{
|
||
|
/* append just-received byte to the TS0 receive history buffer */
|
||
|
e1_rx_hist_add(e1i, inb);
|
||
|
|
||
|
/* notify the FSM that a new TS0 byte was received */
|
||
|
osmo_fsm_inst_dispatch(e1i->rx.fi, E1_AE_RX_TS0, NULL);
|
||
|
|
||
|
e1i->rx.frame_nr = (e1i->rx.frame_nr + 1) % 16;
|
||
|
}
|
||
|
|
||
|
static void e1_rx_tsN(struct osmo_e1f_instance_ts *e1t, uint8_t inb)
|
||
|
{
|
||
|
struct msgb *msg;
|
||
|
int count, rc;
|
||
|
|
||
|
if (!e1t->rx.enabled)
|
||
|
return;
|
||
|
|
||
|
if (!e1t->rx.msg)
|
||
|
e1t->rx.msg = msgb_alloc(e1t->rx.granularity, "E1 Rx");
|
||
|
msg = e1t->rx.msg;
|
||
|
OSMO_ASSERT(msg);
|
||
|
|
||
|
switch (e1t->mode) {
|
||
|
case OSMO_E1F_TS_RAW:
|
||
|
/* append byte at end of msgb */
|
||
|
msgb_put_u8(msg, inb);
|
||
|
/* flush msgb, if full */
|
||
|
if (msgb_tailroom(msg) <= 0) {
|
||
|
goto flush;
|
||
|
}
|
||
|
break;
|
||
|
case OSMO_E1F_TS_HDLC_CRC:
|
||
|
rc = osmo_isdnhdlc_decode(&e1t->rx.hdlc, &inb, 1, &count,
|
||
|
msgb_data(msg), msgb_tailroom(msg));
|
||
|
switch (rc) {
|
||
|
case -OSMO_HDLC_FRAMING_ERROR:
|
||
|
fprintf(stdout, "Framing Error\n");
|
||
|
break;
|
||
|
case -OSMO_HDLC_CRC_ERROR:
|
||
|
fprintf(stdout, "CRC Error\n");
|
||
|
break;
|
||
|
case -OSMO_HDLC_LENGTH_ERROR:
|
||
|
fprintf(stdout, "Length Error\n");
|
||
|
break;
|
||
|
case 0:
|
||
|
/* no output yet */
|
||
|
break;
|
||
|
default:
|
||
|
msgb_put(msg, rc);
|
||
|
goto flush;
|
||
|
}
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
return;
|
||
|
flush:
|
||
|
|
||
|
if (!e1t->rx.data_cb)
|
||
|
msgb_free(msg);
|
||
|
else
|
||
|
e1t->rx.data_cb(e1t, msg);
|
||
|
e1t->rx.msg = NULL;
|
||
|
}
|
||
|
|
||
|
/*! Receive a single E1 frame of 32x8 (=256) bits
|
||
|
* \param e1i E1 instance for which the frame was received
|
||
|
* \param[in] in_frame caller-provided buffer of 32 octets
|
||
|
*
|
||
|
* The idea is that whoever calls us will already have done the bit-alignment,
|
||
|
* i.e. the first bit of TS0 of the frame will be octet-aligned and hence the
|
||
|
* entire 256bit buffer is provided as octet-aligned 32bytes in \a in_frame.
|
||
|
*/
|
||
|
int osmo_e1f_rx_frame(struct osmo_e1f_instance *e1i, const uint8_t *in_frame)
|
||
|
{
|
||
|
int i;
|
||
|
|
||
|
e1_rx_update_crc4(e1i, in_frame);
|
||
|
|
||
|
e1_rx_ts0(e1i, in_frame[0]);
|
||
|
|
||
|
for (i = 1; i < ARRAY_SIZE(e1i->ts); i++) {
|
||
|
struct osmo_e1f_instance_ts *e1t = &e1i->ts[i];
|
||
|
e1_rx_tsN(e1t, in_frame[i]);
|
||
|
}
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
int osmo_e1f_init(void)
|
||
|
{
|
||
|
return osmo_fsm_register(&e1_align_fsm);
|
||
|
}
|