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path: root/drivers/tty/n_gsm.c
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Diffstat (limited to 'drivers/tty/n_gsm.c')
-rw-r--r--drivers/tty/n_gsm.c194
1 files changed, 105 insertions, 89 deletions
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 05562b3cca45..aafc3bb60e52 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -72,6 +72,8 @@ module_param(debug, int, 0600);
*/
#define MAX_MRU 1500
#define MAX_MTU 1500
+/* SOF, ADDR, CTRL, LEN1, LEN2, ..., FCS, EOF */
+#define PROT_OVERHEAD 7
#define GSM_NET_TX_TIMEOUT (HZ*10)
/**
@@ -230,6 +232,7 @@ struct gsm_mux {
int initiator; /* Did we initiate connection */
bool dead; /* Has the mux been shut down */
struct gsm_dlci *dlci[NUM_DLCI];
+ int old_c_iflag; /* termios c_iflag value before attach */
bool constipated; /* Asked by remote to shut up */
spinlock_t tx_lock;
@@ -818,7 +821,7 @@ static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
break;
case 2: /* Unstructed with modem bits.
Always one byte as we never send inline break data */
- *dp++ = gsm_encode_modem(dlci);
+ *dp++ = (gsm_encode_modem(dlci) << 1) | EA;
break;
}
WARN_ON(kfifo_out_locked(&dlci->fifo, dp , len, &dlci->lock) != len);
@@ -1295,11 +1298,12 @@ static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
{
- struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
+ struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 2, gsm->ftype);
if (msg == NULL)
return;
- msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
- memcpy(msg->data + 1, ctrl->data, ctrl->len);
+ msg->data[0] = (ctrl->cmd << 1) | CR | EA; /* command */
+ msg->data[1] = (ctrl->len << 1) | EA;
+ memcpy(msg->data + 2, ctrl->data, ctrl->len);
gsm_data_queue(gsm->dlci[0], msg);
}
@@ -1322,7 +1326,6 @@ static void gsm_control_retransmit(struct timer_list *t)
spin_lock_irqsave(&gsm->control_lock, flags);
ctrl = gsm->pending_cmd;
if (ctrl) {
- gsm->cretries--;
if (gsm->cretries == 0) {
gsm->pending_cmd = NULL;
ctrl->error = -ETIMEDOUT;
@@ -1331,6 +1334,7 @@ static void gsm_control_retransmit(struct timer_list *t)
wake_up(&gsm->event);
return;
}
+ gsm->cretries--;
gsm_control_transmit(gsm, ctrl);
mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
}
@@ -1371,7 +1375,7 @@ retry:
/* If DLCI0 is in ADM mode skip retries, it won't respond */
if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
- gsm->cretries = 1;
+ gsm->cretries = 0;
else
gsm->cretries = gsm->n2;
@@ -1419,13 +1423,17 @@ static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
static void gsm_dlci_close(struct gsm_dlci *dlci)
{
+ unsigned long flags;
+
del_timer(&dlci->t1);
if (debug & 8)
pr_debug("DLCI %d goes closed.\n", dlci->addr);
dlci->state = DLCI_CLOSED;
if (dlci->addr != 0) {
tty_port_tty_hangup(&dlci->port, false);
+ spin_lock_irqsave(&dlci->lock, flags);
kfifo_reset(&dlci->fifo);
+ spin_unlock_irqrestore(&dlci->lock, flags);
/* Ensure that gsmtty_open() can return. */
tty_port_set_initialized(&dlci->port, 0);
wake_up_interruptible(&dlci->port.open_wait);
@@ -1810,7 +1818,6 @@ static void gsm_queue(struct gsm_mux *gsm)
gsm_response(gsm, address, UA);
gsm_dlci_close(dlci);
break;
- case UA:
case UA|PF:
if (cr == 0 || dlci == NULL)
break;
@@ -1954,6 +1961,16 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
{
+ /* handle XON/XOFF */
+ if ((c & ISO_IEC_646_MASK) == XON) {
+ gsm->constipated = true;
+ return;
+ } else if ((c & ISO_IEC_646_MASK) == XOFF) {
+ gsm->constipated = false;
+ /* Kick the link in case it is idling */
+ gsm_data_kick(gsm, NULL);
+ return;
+ }
if (c == GSM1_SOF) {
/* EOF is only valid in frame if we have got to the data state
and received at least one byte (the FCS) */
@@ -1968,7 +1985,8 @@ static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
}
/* Any partial frame was a runt so go back to start */
if (gsm->state != GSM_START) {
- gsm->malformed++;
+ if (gsm->state != GSM_SEARCH)
+ gsm->malformed++;
gsm->state = GSM_START;
}
/* A SOF in GSM_START means we are still reading idling or
@@ -2040,74 +2058,43 @@ 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
+ * @disc: disconnect link?
*
* Clean up the bits of the mux which are the same for all framing
* protocols. Remove the mux from the mux table, stop all the timers
* and then shut down each device hanging up the channels as we go.
*/
-static void gsm_cleanup_mux(struct gsm_mux *gsm)
+static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc)
{
int i;
struct gsm_dlci *dlci = gsm->dlci[0];
struct gsm_msg *txq, *ntxq;
gsm->dead = true;
+ mutex_lock(&gsm->mutex);
- spin_lock(&gsm_mux_lock);
- for (i = 0; i < MAX_MUX; i++) {
- if (gsm_mux[i] == gsm) {
- gsm_mux[i] = NULL;
- break;
+ if (dlci) {
+ if (disc && dlci->state != DLCI_CLOSED) {
+ gsm_dlci_begin_close(dlci);
+ wait_event(gsm->event, dlci->state == DLCI_CLOSED);
}
+ dlci->dead = true;
}
- spin_unlock(&gsm_mux_lock);
- /* open failed before registering => nothing to do */
- if (i == MAX_MUX)
- return;
+ /* Finish outstanding timers, making sure they are done */
del_timer_sync(&gsm->t2_timer);
- /* Now we are sure T2 has stopped */
- if (dlci)
- dlci->dead = true;
- /* Free up any link layer users */
- mutex_lock(&gsm->mutex);
- for (i = 0; i < NUM_DLCI; i++)
+ /* Free up any link layer users and finally the control channel */
+ for (i = NUM_DLCI - 1; i >= 0; i--)
if (gsm->dlci[i])
gsm_dlci_release(gsm->dlci[i]);
mutex_unlock(&gsm->mutex);
/* Now wipe the queues */
+ tty_ldisc_flush(gsm->tty);
list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
kfree(txq);
INIT_LIST_HEAD(&gsm->tx_list);
@@ -2125,7 +2112,6 @@ static void gsm_cleanup_mux(struct gsm_mux *gsm)
static int gsm_activate_mux(struct gsm_mux *gsm)
{
struct gsm_dlci *dlci;
- int i = 0;
timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
init_waitqueue_head(&gsm->event);
@@ -2137,18 +2123,6 @@ static int gsm_activate_mux(struct gsm_mux *gsm)
else
gsm->receive = gsm1_receive;
- spin_lock(&gsm_mux_lock);
- for (i = 0; i < MAX_MUX; i++) {
- if (gsm_mux[i] == NULL) {
- gsm->num = i;
- gsm_mux[i] = gsm;
- break;
- }
- }
- spin_unlock(&gsm_mux_lock);
- if (i == MAX_MUX)
- return -EBUSY;
-
dlci = gsm_dlci_alloc(gsm, 0);
if (dlci == NULL)
return -ENOMEM;
@@ -2164,6 +2138,15 @@ static int gsm_activate_mux(struct gsm_mux *gsm)
*/
static void gsm_free_mux(struct gsm_mux *gsm)
{
+ int i;
+
+ for (i = 0; i < MAX_MUX; i++) {
+ if (gsm == gsm_mux[i]) {
+ gsm_mux[i] = NULL;
+ break;
+ }
+ }
+ mutex_destroy(&gsm->mutex);
kfree(gsm->txframe);
kfree(gsm->buf);
kfree(gsm);
@@ -2183,12 +2166,20 @@ static void gsm_free_muxr(struct kref *ref)
static inline void mux_get(struct gsm_mux *gsm)
{
+ unsigned long flags;
+
+ spin_lock_irqsave(&gsm_mux_lock, flags);
kref_get(&gsm->ref);
+ spin_unlock_irqrestore(&gsm_mux_lock, flags);
}
static inline void mux_put(struct gsm_mux *gsm)
{
+ unsigned long flags;
+
+ spin_lock_irqsave(&gsm_mux_lock, flags);
kref_put(&gsm->ref, gsm_free_muxr);
+ spin_unlock_irqrestore(&gsm_mux_lock, flags);
}
static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
@@ -2209,6 +2200,7 @@ static inline unsigned int mux_line_to_num(unsigned int line)
static struct gsm_mux *gsm_alloc_mux(void)
{
+ int i;
struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
if (gsm == NULL)
return NULL;
@@ -2217,7 +2209,7 @@ static struct gsm_mux *gsm_alloc_mux(void)
kfree(gsm);
return NULL;
}
- gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
+ gsm->txframe = kmalloc(2 * (MAX_MTU + PROT_OVERHEAD - 1), GFP_KERNEL);
if (gsm->txframe == NULL) {
kfree(gsm->buf);
kfree(gsm);
@@ -2238,6 +2230,26 @@ static struct gsm_mux *gsm_alloc_mux(void)
gsm->mtu = 64;
gsm->dead = true; /* Avoid early tty opens */
+ /* Store the instance to the mux array or abort if no space is
+ * available.
+ */
+ spin_lock(&gsm_mux_lock);
+ for (i = 0; i < MAX_MUX; i++) {
+ if (!gsm_mux[i]) {
+ gsm_mux[i] = gsm;
+ gsm->num = i;
+ break;
+ }
+ }
+ spin_unlock(&gsm_mux_lock);
+ if (i == MAX_MUX) {
+ mutex_destroy(&gsm->mutex);
+ kfree(gsm->txframe);
+ kfree(gsm->buf);
+ kfree(gsm);
+ return NULL;
+ }
+
return gsm;
}
@@ -2273,7 +2285,7 @@ static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
/* Check the MRU/MTU range looks sane */
if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
return -EINVAL;
- if (c->n2 < 3)
+ if (c->n2 > 255)
return -EINVAL;
if (c->encapsulation > 1) /* Basic, advanced, no I */
return -EINVAL;
@@ -2304,19 +2316,11 @@ static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
/*
* Close down what is needed, restart and initiate the new
- * configuration
+ * configuration. On the first time there is no DLCI[0]
+ * and closing or cleaning up is not necessary.
*/
-
- if (need_close || need_restart) {
- int ret;
-
- ret = gsm_disconnect(gsm);
-
- if (ret)
- return ret;
- }
- if (need_restart)
- gsm_cleanup_mux(gsm);
+ if (need_close || need_restart)
+ gsm_cleanup_mux(gsm, true);
gsm->initiator = c->initiator;
gsm->mru = c->mru;
@@ -2385,6 +2389,9 @@ static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
int ret, i;
gsm->tty = tty_kref_get(tty);
+ /* Turn off tty XON/XOFF handling to handle it explicitly. */
+ gsm->old_c_iflag = tty->termios.c_iflag;
+ tty->termios.c_iflag &= (IXON | IXOFF);
ret = gsm_activate_mux(gsm);
if (ret != 0)
tty_kref_put(gsm->tty);
@@ -2425,7 +2432,8 @@ static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
WARN_ON(tty != gsm->tty);
for (i = 1; i < NUM_DLCI; i++)
tty_unregister_device(gsm_tty_driver, base + i);
- gsm_cleanup_mux(gsm);
+ /* Restore tty XON/XOFF handling. */
+ gsm->tty->termios.c_iflag = gsm->old_c_iflag;
tty_kref_put(gsm->tty);
gsm->tty = NULL;
}
@@ -2493,6 +2501,12 @@ static void gsmld_close(struct tty_struct *tty)
{
struct gsm_mux *gsm = tty->disc_data;
+ /* The ldisc locks and closes the port before calling our close. This
+ * means we have no way to do a proper disconnect. We will not bother
+ * to do one.
+ */
+ gsm_cleanup_mux(gsm, false);
+
gsmld_detach_gsm(tty, gsm);
gsmld_flush_buffer(tty);
@@ -2531,7 +2545,7 @@ static int gsmld_open(struct tty_struct *tty)
ret = gsmld_attach_gsm(tty, gsm);
if (ret != 0) {
- gsm_cleanup_mux(gsm);
+ gsm_cleanup_mux(gsm, false);
mux_put(gsm);
}
return ret;
@@ -2888,19 +2902,17 @@ static struct tty_ldisc_ops tty_ldisc_packet = {
static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
{
- u8 modembits[5];
+ u8 modembits[3];
struct gsm_control *ctrl;
int len = 2;
- if (brk)
+ modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */
+ modembits[1] = (gsm_encode_modem(dlci) << 1) | EA;
+ if (brk) {
+ modembits[2] = (brk << 4) | 2 | EA; /* Length, Break, EA */
len++;
-
- modembits[0] = len << 1 | EA; /* Data bytes */
- modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
- modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
- if (brk)
- modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
- ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
+ }
+ ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len);
if (ctrl == NULL)
return -ENOMEM;
return gsm_control_wait(dlci->gsm, ctrl);
@@ -3085,13 +3097,17 @@ static int gsmtty_chars_in_buffer(struct tty_struct *tty)
static void gsmtty_flush_buffer(struct tty_struct *tty)
{
struct gsm_dlci *dlci = tty->driver_data;
+ unsigned long flags;
+
if (dlci->state == DLCI_CLOSED)
return;
/* Caution needed: If we implement reliable transport classes
then the data being transmitted can't simply be junked once
it has first hit the stack. Until then we can just blow it
away */
+ spin_lock_irqsave(&dlci->lock, flags);
kfifo_reset(&dlci->fifo);
+ spin_unlock_irqrestore(&dlci->lock, flags);
/* Need to unhook this DLCI from the transmit queue logic */
}
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-04-20 03:43:49 +0000