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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.c61
1 files changed, 39 insertions, 22 deletions
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 0b1808e3a912..fa92f727fdf8 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -439,7 +439,7 @@ static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
modembits |= MDM_RTR;
if (dlci->modem_tx & TIOCM_RI)
modembits |= MDM_IC;
- if (dlci->modem_tx & TIOCM_CD)
+ if (dlci->modem_tx & TIOCM_CD || dlci->gsm->initiator)
modembits |= MDM_DV;
return modembits;
}
@@ -448,7 +448,7 @@ static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
* gsm_print_packet - display a frame for debug
* @hdr: header to print before decode
* @addr: address EA from the frame
- * @cr: C/R bit from the frame
+ * @cr: C/R bit seen as initiator
* @control: control including PF bit
* @data: following data bytes
* @dlen: length of data
@@ -548,7 +548,7 @@ static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
* gsm_send - send a control frame
* @gsm: our GSM mux
* @addr: address for control frame
- * @cr: command/response bit
+ * @cr: command/response bit seen as initiator
* @control: control byte including PF bit
*
* Format up and transmit a control frame. These do not go via the
@@ -563,11 +563,15 @@ static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
int len;
u8 cbuf[10];
u8 ibuf[3];
+ int ocr;
+
+ /* toggle C/R coding if not initiator */
+ ocr = cr ^ (gsm->initiator ? 0 : 1);
switch (gsm->encoding) {
case 0:
cbuf[0] = GSM0_SOF;
- cbuf[1] = (addr << 2) | (cr << 1) | EA;
+ cbuf[1] = (addr << 2) | (ocr << 1) | EA;
cbuf[2] = control;
cbuf[3] = EA; /* Length of data = 0 */
cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
@@ -577,7 +581,7 @@ static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
case 1:
case 2:
/* Control frame + packing (but not frame stuffing) in mode 1 */
- ibuf[0] = (addr << 2) | (cr << 1) | EA;
+ ibuf[0] = (addr << 2) | (ocr << 1) | EA;
ibuf[1] = control;
ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
/* Stuffing may double the size worst case */
@@ -611,7 +615,7 @@ static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
{
- gsm_send(gsm, addr, 1, control);
+ gsm_send(gsm, addr, 0, control);
}
/**
@@ -1017,25 +1021,25 @@ static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data,
* @tty: virtual tty bound to the DLCI
* @dlci: DLCI to affect
* @modem: modem bits (full EA)
- * @clen: command length
+ * @slen: number of signal octets
*
* Used when a modem control message or line state inline in adaption
* layer 2 is processed. Sort out the local modem state and throttles
*/
static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
- u32 modem, int clen)
+ u32 modem, int slen)
{
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
- either be 2 or 3 respectively. This is specified in section
- 5.4.6.3.7 of the 27.010 mux spec. */
+ /* The modem status command can either contain one octet (V.24 signals)
+ * or two octets (V.24 signals + break signals). This is specified in
+ * section 5.4.6.3.7 of the 07.10 mux spec.
+ */
- if (clen == 2)
+ if (slen == 1)
modem = modem & 0x7f;
else {
brk = modem & 0x7f;
@@ -1092,6 +1096,7 @@ static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
unsigned int brk = 0;
struct gsm_dlci *dlci;
int len = clen;
+ int slen;
const u8 *dp = data;
struct tty_struct *tty;
@@ -1111,6 +1116,7 @@ static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
return;
dlci = gsm->dlci[addr];
+ slen = len;
while (gsm_read_ea(&modem, *dp++) == 0) {
len--;
if (len == 0)
@@ -1127,7 +1133,7 @@ static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
modem |= (brk & 0x7f);
}
tty = tty_port_tty_get(&dlci->port);
- gsm_process_modem(tty, dlci, modem, clen);
+ gsm_process_modem(tty, dlci, modem, slen);
if (tty) {
tty_wakeup(tty);
tty_kref_put(tty);
@@ -1451,6 +1457,9 @@ static void gsm_dlci_close(struct gsm_dlci *dlci)
if (dlci->addr != 0) {
tty_port_tty_hangup(&dlci->port, false);
kfifo_reset(&dlci->fifo);
+ /* Ensure that gsmtty_open() can return. */
+ tty_port_set_initialized(&dlci->port, 0);
+ wake_up_interruptible(&dlci->port.open_wait);
} else
dlci->gsm->dead = true;
/* Unregister gsmtty driver,report gsmtty dev remove uevent for user */
@@ -1514,7 +1523,7 @@ static void gsm_dlci_t1(struct timer_list *t)
dlci->mode = DLCI_MODE_ADM;
gsm_dlci_open(dlci);
} else {
- gsm_dlci_close(dlci);
+ gsm_dlci_begin_close(dlci); /* prevent half open link */
}
break;
@@ -1593,6 +1602,7 @@ static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
struct tty_struct *tty;
unsigned int modem = 0;
int len = clen;
+ int slen = 0;
if (debug & 16)
pr_debug("%d bytes for tty\n", len);
@@ -1605,12 +1615,14 @@ static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
case 2: /* Asynchronous serial with line state in each frame */
while (gsm_read_ea(&modem, *data++) == 0) {
len--;
+ slen++;
if (len == 0)
return;
}
+ slen++;
tty = tty_port_tty_get(port);
if (tty) {
- gsm_process_modem(tty, dlci, modem, clen);
+ gsm_process_modem(tty, dlci, modem, slen);
tty_kref_put(tty);
}
fallthrough;
@@ -1748,7 +1760,12 @@ static void gsm_dlci_release(struct gsm_dlci *dlci)
gsm_destroy_network(dlci);
mutex_unlock(&dlci->mutex);
- tty_hangup(tty);
+ /* We cannot use tty_hangup() because in tty_kref_put() the tty
+ * driver assumes that the hangup queue is free and reuses it to
+ * queue release_one_tty() -> NULL pointer panic in
+ * process_one_work().
+ */
+ tty_vhangup(tty);
tty_port_tty_set(&dlci->port, NULL);
tty_kref_put(tty);
@@ -1800,10 +1817,10 @@ static void gsm_queue(struct gsm_mux *gsm)
goto invalid;
cr = gsm->address & 1; /* C/R bit */
+ cr ^= gsm->initiator ? 0 : 1; /* Flip so 1 always means command */
gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
- cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
dlci = gsm->dlci[address];
switch (gsm->control) {
@@ -3234,9 +3251,9 @@ static void gsmtty_throttle(struct tty_struct *tty)
if (dlci->state == DLCI_CLOSED)
return;
if (C_CRTSCTS(tty))
- dlci->modem_tx &= ~TIOCM_DTR;
+ dlci->modem_tx &= ~TIOCM_RTS;
dlci->throttled = true;
- /* Send an MSC with DTR cleared */
+ /* Send an MSC with RTS cleared */
gsmtty_modem_update(dlci, 0);
}
@@ -3246,9 +3263,9 @@ static void gsmtty_unthrottle(struct tty_struct *tty)
if (dlci->state == DLCI_CLOSED)
return;
if (C_CRTSCTS(tty))
- dlci->modem_tx |= TIOCM_DTR;
+ dlci->modem_tx |= TIOCM_RTS;
dlci->throttled = false;
- /* Send an MSC with DTR set */
+ /* Send an MSC with RTS set */
gsmtty_modem_update(dlci, 0);
}
generated by cgit (git 2.34.1) at 2024-05-04 05:46:23 +0000