summaryrefslogtreecommitdiffstats
path: root/drivers/tty/n_gsm.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/tty/n_gsm.c')
-rw-r--r--drivers/tty/n_gsm.c59
1 files changed, 46 insertions, 13 deletions
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 04ef3ef0a42..5256087dd81 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -184,6 +184,9 @@ struct gsm_mux {
#define GSM_DATA 5
#define GSM_FCS 6
#define GSM_OVERRUN 7
+#define GSM_LEN0 8
+#define GSM_LEN1 9
+#define GSM_SSOF 10
unsigned int len;
unsigned int address;
unsigned int count;
@@ -191,6 +194,7 @@ struct gsm_mux {
int encoding;
u8 control;
u8 fcs;
+ u8 received_fcs;
u8 *txframe; /* TX framing buffer */
/* Methods for the receiver side */
@@ -1623,7 +1627,6 @@ static void gsm_dlci_free(struct gsm_dlci *dlci)
kfree(dlci);
}
-
/*
* LAPBish link layer logic
*/
@@ -1648,6 +1651,8 @@ static void gsm_queue(struct gsm_mux *gsm)
if ((gsm->control & ~PF) == UI)
gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
+ /* generate final CRC with received FCS */
+ gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
if (gsm->fcs != GOOD_FCS) {
gsm->bad_fcs++;
if (debug & 4)
@@ -1746,6 +1751,8 @@ invalid:
static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
{
+ unsigned int len;
+
switch (gsm->state) {
case GSM_SEARCH: /* SOF marker */
if (c == GSM0_SOF) {
@@ -1754,8 +1761,8 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
gsm->len = 0;
gsm->fcs = INIT_FCS;
}
- break; /* Address EA */
- case GSM_ADDRESS:
+ break;
+ case GSM_ADDRESS: /* Address EA */
gsm->fcs = gsm_fcs_add(gsm->fcs, c);
if (gsm_read_ea(&gsm->address, c))
gsm->state = GSM_CONTROL;
@@ -1763,9 +1770,9 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
case GSM_CONTROL: /* Control Byte */
gsm->fcs = gsm_fcs_add(gsm->fcs, c);
gsm->control = c;
- gsm->state = GSM_LEN;
+ gsm->state = GSM_LEN0;
break;
- case GSM_LEN: /* Length EA */
+ case GSM_LEN0: /* Length EA */
gsm->fcs = gsm_fcs_add(gsm->fcs, c);
if (gsm_read_ea(&gsm->len, c)) {
if (gsm->len > gsm->mru) {
@@ -1774,8 +1781,28 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
break;
}
gsm->count = 0;
- gsm->state = GSM_DATA;
+ if (!gsm->len)
+ gsm->state = GSM_FCS;
+ else
+ gsm->state = GSM_DATA;
+ break;
}
+ gsm->state = GSM_LEN1;
+ break;
+ case GSM_LEN1:
+ gsm->fcs = gsm_fcs_add(gsm->fcs, c);
+ len = c;
+ gsm->len |= len << 7;
+ if (gsm->len > gsm->mru) {
+ gsm->bad_size++;
+ gsm->state = GSM_SEARCH;
+ break;
+ }
+ gsm->count = 0;
+ if (!gsm->len)
+ gsm->state = GSM_FCS;
+ else
+ gsm->state = GSM_DATA;
break;
case GSM_DATA: /* Data */
gsm->buf[gsm->count++] = c;
@@ -1783,16 +1810,25 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
gsm->state = GSM_FCS;
break;
case GSM_FCS: /* FCS follows the packet */
- gsm->fcs = c;
+ gsm->received_fcs = c;
+ if (c == GSM0_SOF) {
+ gsm->state = GSM_SEARCH;
+ break;
+ }
gsm_queue(gsm);
- /* And then back for the next frame */
- gsm->state = GSM_SEARCH;
+ gsm->state = GSM_SSOF;
+ break;
+ case GSM_SSOF:
+ if (c == GSM0_SOF) {
+ gsm->state = GSM_SEARCH;
+ break;
+ }
break;
}
}
/**
- * gsm0_receive - perform processing for non-transparency
+ * gsm1_receive - perform processing for non-transparency
* @gsm: gsm data for this ldisc instance
* @c: character
*
@@ -2032,9 +2068,6 @@ struct gsm_mux *gsm_alloc_mux(void)
}
EXPORT_SYMBOL_GPL(gsm_alloc_mux);
-
-
-
/**
* gsmld_output - write to link
* @gsm: our mux