[PATCH 5.15 118/230] tty: n_gsm: Modify CR,PF bit when config requester

Greg Kroah-Hartman
2022-07-11T09:51:25Z

From: Zhenguo Zhao <Zhenguo.Zhao1@unisoc.com>

[ Upstream commit cc0f42122a7e7a5ede9c5f2a41199128b8449eda ]

When n_gsm config "initiator=0",as requester,gsmld receives dlci SABM/DISC
control command frame,but send UA frame is error.

Example:
Gsmld receive dlc0 SABM frame "f9 03 3f 01 1c f9",now it sends UA
frame "f9 01 63 01 a3 f9",CR and PF bit are 0,but it should be set
1 from requster to initiator.

Kernel test log as follows:

Before modify

[ 271.732031] c1 gsmld_receive: 00000000: f9 03 3f 01 1c f9
[ 271.741719] c1 <-- 0) C: SABM(P)
[ 271.749483] c1 gsmld_output: 00000000: f9 01 63 01 a3 f9
[ 271.758337] c1 --> 0) R: UA(F)

After modify

[ 261.233188] c0 gsmld_receive: 00000000: f9 03 3f 01 1c f9
[ 261.242767] c0 <-- 0) C: SABM(P)
[ 261.250497] c0 gsmld_output: 00000000: f9 03 73 01 d7 f9
[ 261.259759] c0 --> 0) C: UA(P)

Signed-off-by: Zhenguo Zhao <Zhenguo.Zhao1@unisoc.com>
Link: https://lore.kernel.org/r/1629461872-26965-3-git-send-email-zhenguo6858@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/tty/n_gsm.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 6734ef22c304..91ce8e6e889a 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -625,7 +625,7 @@ 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, 0, control);
+ gsm_send(gsm, addr, 1, control);
}

/**
@@ -1818,9 +1818,9 @@ static void gsm_queue(struct gsm_mux *gsm)
if (dlci == NULL)
return;
if (dlci->dead)
- gsm_response(gsm, address, DM);
+ gsm_response(gsm, address, DM|PF);
else {
- gsm_response(gsm, address, UA);
+ gsm_response(gsm, address, UA|PF);
gsm_dlci_open(dlci);
}
break;
@@ -1828,11 +1828,11 @@ static void gsm_queue(struct gsm_mux *gsm)
if (cr == 0)
goto invalid;
if (dlci == NULL || dlci->state == DLCI_CLOSED) {
- gsm_response(gsm, address, DM);
+ gsm_response(gsm, address, DM|PF);
return;
}
/* Real close complete */
- gsm_response(gsm, address, UA);
+ gsm_response(gsm, address, UA|PF);
gsm_dlci_close(dlci);
break;
case UA|PF:
--
2.35.1