diff options
| -rw-r--r-- | Documentation/serial/n_gsm.txt | 7 | ||||
| -rw-r--r-- | drivers/tty/n_gsm.c | 54 |
2 files changed, 42 insertions, 19 deletions
diff --git a/Documentation/serial/n_gsm.txt b/Documentation/serial/n_gsm.txt index a5d91126a8f7..875361bb7cb4 100644 --- a/Documentation/serial/n_gsm.txt +++ b/Documentation/serial/n_gsm.txt @@ -77,6 +77,13 @@ for example, it's possible : 6- first close all virtual ports before closing the physical port. +Note that after closing the physical port the modem is still in multiplexing +mode. This may prevent a successful re-opening of the port later. To avoid +this situation either reset the modem if your hardware allows that or send +a disconnect command frame manually before initializing the multiplexing mode +for the second time. The byte sequence for the disconnect command frame is: +0xf9, 0x03, 0xef, 0x03, 0xc3, 0x16, 0xf9. + Additional Documentation ------------------------ More practical details on the protocol and how it's supported by industrial diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 2667a205a5ab..363a8ca824ad 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -2015,6 +2015,33 @@ static void gsm_error(struct gsm_mux *gsm, gsm->io_error++; } +static int gsm_disconnect(struct gsm_mux *gsm) +{ + struct gsm_dlci *dlci = gsm->dlci[0]; + struct gsm_control *gc; + + if (!dlci) + return 0; + + /* In theory disconnecting DLCI 0 is sufficient but for some + modems this is apparently not the case. */ + gc = gsm_control_send(gsm, CMD_CLD, NULL, 0); + if (gc) + gsm_control_wait(gsm, gc); + + del_timer_sync(&gsm->t2_timer); + /* Now we are sure T2 has stopped */ + + gsm_dlci_begin_close(dlci); + wait_event_interruptible(gsm->event, + dlci->state == DLCI_CLOSED); + + if (signal_pending(current)) + return -EINTR; + + return 0; +} + /** * gsm_cleanup_mux - generic GSM protocol cleanup * @gsm: our mux @@ -2029,7 +2056,6 @@ static void gsm_cleanup_mux(struct gsm_mux *gsm) int i; struct gsm_dlci *dlci = gsm->dlci[0]; struct gsm_msg *txq, *ntxq; - struct gsm_control *gc; gsm->dead = 1; @@ -2045,21 +2071,11 @@ static void gsm_cleanup_mux(struct gsm_mux *gsm) if (i == MAX_MUX) return; - /* In theory disconnecting DLCI 0 is sufficient but for some - modems this is apparently not the case. */ - if (dlci) { - gc = gsm_control_send(gsm, CMD_CLD, NULL, 0); - if (gc) - gsm_control_wait(gsm, gc); - } del_timer_sync(&gsm->t2_timer); /* Now we are sure T2 has stopped */ - if (dlci) { + if (dlci) dlci->dead = 1; - gsm_dlci_begin_close(dlci); - wait_event_interruptible(gsm->event, - dlci->state == DLCI_CLOSED); - } + /* Free up any link layer users */ mutex_lock(&gsm->mutex); for (i = 0; i < NUM_DLCI; i++) @@ -2519,12 +2535,12 @@ static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm, */ if (need_close || need_restart) { - gsm_dlci_begin_close(gsm->dlci[0]); - /* This will timeout if the link is down due to N2 expiring */ - wait_event_interruptible(gsm->event, - gsm->dlci[0]->state == DLCI_CLOSED); - if (signal_pending(current)) - return -EINTR; + int ret; + + ret = gsm_disconnect(gsm); + + if (ret) + return ret; } if (need_restart) gsm_cleanup_mux(gsm); |