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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.c144
1 files changed, 87 insertions, 57 deletions
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index c43b683b6eb8..1e8e8ce55959 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -108,7 +108,7 @@ struct gsm_mux_net {
*/
struct gsm_msg {
- struct gsm_msg *next;
+ struct list_head list;
u8 addr; /* DLCI address + flags */
u8 ctrl; /* Control byte + flags */
unsigned int len; /* Length of data block (can be zero) */
@@ -245,8 +245,7 @@ struct gsm_mux {
unsigned int tx_bytes; /* TX data outstanding */
#define TX_THRESH_HI 8192
#define TX_THRESH_LO 2048
- struct gsm_msg *tx_head; /* Pending data packets */
- struct gsm_msg *tx_tail;
+ struct list_head tx_list; /* Pending data packets */
/* Control messages */
struct timer_list t2_timer; /* Retransmit timer for commands */
@@ -489,7 +488,7 @@ static void gsm_print_packet(const char *hdr, int addr, int cr,
default:
if (!(control & 0x01)) {
pr_cont("I N(S)%d N(R)%d",
- (control & 0x0E) >> 1, (control & 0xE) >> 5);
+ (control & 0x0E) >> 1, (control & 0xE0) >> 5);
} else switch (control & 0x0F) {
case RR:
pr_cont("RR(%d)", (control & 0xE0) >> 5);
@@ -663,7 +662,7 @@ static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
m->len = len;
m->addr = addr;
m->ctrl = ctrl;
- m->next = NULL;
+ INIT_LIST_HEAD(&m->list);
return m;
}
@@ -673,22 +672,21 @@ 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
*/
static void gsm_data_kick(struct gsm_mux *gsm)
{
- struct gsm_msg *msg = gsm->tx_head;
+ struct gsm_msg *msg, *nmsg;
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;
+ list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
+ if (gsm->constipated && msg->addr)
+ continue;
if (gsm->encoding != 0) {
gsm->txframe[0] = GSM1_SOF;
len = gsm_stuff_frame(msg->data,
@@ -711,14 +709,13 @@ 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;
+
+ list_del(&msg->list);
+ kfree(msg);
}
}
@@ -768,11 +765,7 @@ static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
msg->data = dp;
/* Add to the actual output queue */
- if (gsm->tx_tail)
- gsm->tx_tail->next = msg;
- else
- gsm->tx_head = msg;
- gsm->tx_tail = msg;
+ list_add_tail(&msg->list, &gsm->tx_list);
gsm->tx_bytes += msg->len;
gsm_data_kick(gsm);
}
@@ -875,7 +868,7 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
/* dlci->skb is locked by tx_lock */
if (dlci->skb == NULL) {
- dlci->skb = skb_dequeue(&dlci->skb_list);
+ dlci->skb = skb_dequeue_tail(&dlci->skb_list);
if (dlci->skb == NULL)
return 0;
first = 1;
@@ -886,7 +879,7 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
if (len > gsm->mtu) {
if (dlci->adaption == 3) {
/* Over long frame, bin it */
- kfree_skb(dlci->skb);
+ dev_kfree_skb_any(dlci->skb);
dlci->skb = NULL;
return 0;
}
@@ -899,8 +892,11 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
/* FIXME: need a timer or something to kick this so it can't
get stuck with no work outstanding and no buffer free */
- if (msg == NULL)
+ if (msg == NULL) {
+ skb_queue_tail(&dlci->skb_list, dlci->skb);
+ dlci->skb = NULL;
return -ENOMEM;
+ }
dp = msg->data;
if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
@@ -912,7 +908,7 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
skb_pull(dlci->skb, len);
__gsm_data_queue(dlci, msg);
if (last) {
- kfree_skb(dlci->skb);
+ dev_kfree_skb_any(dlci->skb);
dlci->skb = NULL;
}
return size;
@@ -971,16 +967,22 @@ static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
{
unsigned long flags;
+ int sweep;
+
+ if (dlci->constipated)
+ 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);
if (dlci->gsm->tx_bytes == 0) {
if (dlci->net)
gsm_dlci_data_output_framed(dlci->gsm, dlci);
else
gsm_dlci_data_output(dlci->gsm, dlci);
- } else if (dlci->gsm->tx_bytes < TX_THRESH_LO)
- gsm_dlci_data_sweep(dlci->gsm);
+ }
+ if (sweep)
+ gsm_dlci_data_sweep(dlci->gsm);
spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
}
@@ -1027,6 +1029,7 @@ 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
@@ -1038,19 +1041,21 @@ 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) {
/* 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) {
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)
@@ -1061,7 +1066,7 @@ static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
/* Carrier drop -> hangup */
if (tty) {
if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
- if (!(tty->termios->c_cflag & CLOCAL))
+ if (!(tty->termios.c_cflag & CLOCAL))
tty_hangup(tty);
if (brk & 0x01)
tty_insert_flip_char(tty, 0, TTY_BREAK);
@@ -1190,6 +1195,8 @@ static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
u8 *data, int clen)
{
u8 buf[1];
+ unsigned long flags;
+
switch (command) {
case CMD_CLD: {
struct gsm_dlci *dlci = gsm->dlci[0];
@@ -1206,16 +1213,18 @@ 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 */
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 */
+ spin_lock_irqsave(&gsm->tx_lock, flags);
gsm_data_kick(gsm);
+ spin_unlock_irqrestore(&gsm->tx_lock, flags);
+ break;
+ case CMD_FCOFF:
+ /* Modem wants us to STFU */
+ 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 */
@@ -1668,7 +1677,7 @@ static void gsm_dlci_free(struct kref *ref)
dlci->gsm->dlci[dlci->addr] = NULL;
kfifo_free(dlci->fifo);
while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
- kfree_skb(dlci->skb);
+ dev_kfree_skb(dlci->skb);
kfree(dlci);
}
@@ -2007,7 +2016,7 @@ void gsm_cleanup_mux(struct gsm_mux *gsm)
{
int i;
struct gsm_dlci *dlci = gsm->dlci[0];
- struct gsm_msg *txq;
+ struct gsm_msg *txq, *ntxq;
struct gsm_control *gc;
gsm->dead = 1;
@@ -2042,11 +2051,9 @@ void gsm_cleanup_mux(struct gsm_mux *gsm)
if (gsm->dlci[i])
gsm_dlci_release(gsm->dlci[i]);
/* Now wipe the queues */
- for (txq = gsm->tx_head; txq != NULL; txq = gsm->tx_head) {
- gsm->tx_head = txq->next;
+ list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
kfree(txq);
- }
- gsm->tx_tail = NULL;
+ INIT_LIST_HEAD(&gsm->tx_list);
}
EXPORT_SYMBOL_GPL(gsm_cleanup_mux);
@@ -2157,6 +2164,7 @@ struct gsm_mux *gsm_alloc_mux(void)
}
spin_lock_init(&gsm->lock);
kref_init(&gsm->ref);
+ INIT_LIST_HEAD(&gsm->tx_list);
gsm->t1 = T1;
gsm->t2 = T2;
@@ -2273,7 +2281,7 @@ 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;
}
@@ -2377,12 +2385,12 @@ static void gsmld_write_wakeup(struct tty_struct *tty)
/* Queue poll */
clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+ spin_lock_irqsave(&gsm->tx_lock, flags);
gsm_data_kick(gsm);
if (gsm->tx_bytes < TX_THRESH_LO) {
- spin_lock_irqsave(&gsm->tx_lock, flags);
gsm_dlci_data_sweep(gsm);
- spin_unlock_irqrestore(&gsm->tx_lock, flags);
}
+ spin_unlock_irqrestore(&gsm->tx_lock, flags);
}
/**
@@ -2868,14 +2876,14 @@ static const struct tty_port_operations gsm_port_ops = {
.dtr_rts = gsm_dtr_rts,
};
-
-static int gsmtty_open(struct tty_struct *tty, struct file *filp)
+static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
{
struct gsm_mux *gsm;
struct gsm_dlci *dlci;
- struct tty_port *port;
unsigned int line = tty->index;
unsigned int mux = line >> 6;
+ bool alloc = false;
+ int ret;
line = line & 0x3F;
@@ -2889,14 +2897,35 @@ static int gsmtty_open(struct tty_struct *tty, struct file *filp)
gsm = gsm_mux[mux];
if (gsm->dead)
return -EL2HLT;
+ /* If DLCI 0 is not yet fully open return an error. This is ok from a locking
+ perspective as we don't have to worry about this if DLCI0 is lost */
+ if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN)
+ return -EL2NSYNC;
dlci = gsm->dlci[line];
- if (dlci == NULL)
+ if (dlci == NULL) {
+ alloc = true;
dlci = gsm_dlci_alloc(gsm, line);
+ }
if (dlci == NULL)
return -ENOMEM;
- port = &dlci->port;
- port->count++;
+ ret = tty_port_install(&dlci->port, driver, tty);
+ if (ret) {
+ if (alloc)
+ dlci_put(dlci);
+ return ret;
+ }
+
tty->driver_data = dlci;
+
+ return 0;
+}
+
+static int gsmtty_open(struct tty_struct *tty, struct file *filp)
+{
+ struct gsm_dlci *dlci = tty->driver_data;
+ struct tty_port *port = &dlci->port;
+
+ port->count++;
dlci_get(dlci);
dlci_get(dlci->gsm->dlci[0]);
mux_get(dlci->gsm);
@@ -3043,13 +3072,13 @@ static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
the RPN control message. This however rapidly gets nasty as we
then have to remap modem signals each way according to whether
our virtual cable is null modem etc .. */
- tty_termios_copy_hw(tty->termios, old);
+ tty_termios_copy_hw(&tty->termios, old);
}
static void gsmtty_throttle(struct tty_struct *tty)
{
struct gsm_dlci *dlci = tty->driver_data;
- if (tty->termios->c_cflag & CRTSCTS)
+ if (tty->termios.c_cflag & CRTSCTS)
dlci->modem_tx &= ~TIOCM_DTR;
dlci->throttled = 1;
/* Send an MSC with DTR cleared */
@@ -3059,7 +3088,7 @@ static void gsmtty_throttle(struct tty_struct *tty)
static void gsmtty_unthrottle(struct tty_struct *tty)
{
struct gsm_dlci *dlci = tty->driver_data;
- if (tty->termios->c_cflag & CRTSCTS)
+ if (tty->termios.c_cflag & CRTSCTS)
dlci->modem_tx |= TIOCM_DTR;
dlci->throttled = 0;
/* Send an MSC with DTR set */
@@ -3085,6 +3114,7 @@ static int gsmtty_break_ctl(struct tty_struct *tty, int state)
/* Virtual ttys for the demux */
static const struct tty_operations gsmtty_ops = {
+ .install = gsmtty_install,
.open = gsmtty_open,
.close = gsmtty_close,
.write = gsmtty_write,
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.