diff options
| -rw-r--r-- | drivers/tty/n_gsm.c | 79 |
1 files changed, 57 insertions, 22 deletions
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index c028f357024..db15b562a29 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -673,6 +673,8 @@ static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len, * * The tty device has called us to indicate that room has appeared in * the transmit queue. Ram more data into the pipe if we have any + * If we have been flow-stopped by a CMD_FCOFF, then we can only + * send messages on DLCI0 until CMD_FCON * * FIXME: lock against link layer control transmissions */ @@ -680,15 +682,19 @@ static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len, static void gsm_data_kick(struct gsm_mux *gsm) { struct gsm_msg *msg = gsm->tx_head; + struct gsm_msg *free_msg; int len; int skip_sof = 0; - /* FIXME: We need to apply this solely to data messages */ - if (gsm->constipated) - return; - - while (gsm->tx_head != NULL) { - msg = gsm->tx_head; + while (msg) { + if (gsm->constipated && msg->addr) { + msg = msg->next; + continue; + } + if (gsm->dlci[msg->addr]->constipated) { + msg = msg->next; + continue; + } if (gsm->encoding != 0) { gsm->txframe[0] = GSM1_SOF; len = gsm_stuff_frame(msg->data, @@ -711,15 +717,19 @@ static void gsm_data_kick(struct gsm_mux *gsm) len - skip_sof) < 0) break; /* FIXME: Can eliminate one SOF in many more cases */ - gsm->tx_head = msg->next; - if (gsm->tx_head == NULL) - gsm->tx_tail = NULL; gsm->tx_bytes -= msg->len; - kfree(msg); /* For a burst of frames skip the extra SOF within the burst */ skip_sof = 1; + + if (gsm->tx_head == msg) + gsm->tx_head = msg->next; + free_msg = msg; + msg = msg->next; + kfree(free_msg); } + if (!gsm->tx_head) + gsm->tx_tail = NULL; } /** @@ -738,6 +748,8 @@ static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) u8 *dp = msg->data; u8 *fcs = dp + msg->len; + WARN_ONCE(dlci->constipated, "%s: queueing from a constipated DLCI", + __func__); /* Fill in the header */ if (gsm->encoding == 0) { if (msg->len < 128) @@ -944,6 +956,9 @@ static void gsm_dlci_data_sweep(struct gsm_mux *gsm) break; dlci = gsm->dlci[i]; if (dlci == NULL || dlci->constipated) { + if (dlci && (debug & 0x20)) + pr_info("%s: DLCI %d is constipated", + __func__, i); i++; continue; } @@ -973,6 +988,13 @@ static void gsm_dlci_data_kick(struct gsm_dlci *dlci) unsigned long flags; int sweep; + if (dlci->constipated) { + if (debug & 0x20) + pr_info("%s: DLCI %d is constipated", + __func__, dlci->addr); + return; + } + spin_lock_irqsave(&dlci->gsm->tx_lock, flags); /* If we have nothing running then we need to fire up */ sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO); @@ -1030,6 +1052,7 @@ static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci, { int mlines = 0; u8 brk = 0; + int fc; /* The modem status command can either contain one octet (v.24 signals) or two octets (v.24 signals + break signals). The length field will @@ -1041,19 +1064,27 @@ static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci, else { brk = modem & 0x7f; modem = (modem >> 7) & 0x7f; - }; + } /* Flow control/ready to communicate */ - if (modem & MDM_FC) { + fc = (modem & MDM_FC) || !(modem & MDM_RTR); + if (fc && !dlci->constipated) { + if (debug & 0x20) + pr_info("%s: DLCI %d START constipated (tx_bytes=%d)", + __func__, dlci->addr, dlci->gsm->tx_bytes); /* Need to throttle our output on this device */ dlci->constipated = 1; - } - if (modem & MDM_RTC) { - mlines |= TIOCM_DSR | TIOCM_DTR; + } else if (!fc && dlci->constipated) { + if (debug & 0x20) + pr_info("%s: DLCI %d END constipated (tx_bytes=%d)", + __func__, dlci->addr, dlci->gsm->tx_bytes); dlci->constipated = 0; gsm_dlci_data_kick(dlci); } + /* Map modem bits */ + if (modem & MDM_RTC) + mlines |= TIOCM_DSR | TIOCM_DTR; if (modem & MDM_RTR) mlines |= TIOCM_RTS | TIOCM_CTS; if (modem & MDM_IC) @@ -1209,17 +1240,21 @@ static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, gsm_control_reply(gsm, CMD_TEST, data, clen); break; case CMD_FCON: - /* Modem wants us to STFU */ - gsm->constipated = 1; - gsm_control_reply(gsm, CMD_FCON, NULL, 0); - break; - case CMD_FCOFF: /* Modem can accept data again */ + if (debug & 0x20) + pr_info("%s: GSM END constipation", __func__); gsm->constipated = 0; - gsm_control_reply(gsm, CMD_FCOFF, NULL, 0); + gsm_control_reply(gsm, CMD_FCON, NULL, 0); /* Kick the link in case it is idling */ gsm_data_kick(gsm); break; + case CMD_FCOFF: + /* Modem wants us to STFU */ + if (debug & 0x20) + pr_info("%s: GSM START constipation", __func__); + gsm->constipated = 1; + gsm_control_reply(gsm, CMD_FCOFF, NULL, 0); + break; case CMD_MSC: /* Out of band modem line change indicator for a DLCI */ gsm_control_modem(gsm, data, clen); @@ -2276,7 +2311,7 @@ static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, gsm->error(gsm, *dp, flags); break; default: - WARN_ONCE("%s: unknown flag %d\n", + WARN_ONCE(1, "%s: unknown flag %d\n", tty_name(tty, buf), flags); break; } |