mISDN: Implement MISDN_CTRL_RX_OFF for more drivers

MISDN_CTRL_RX_OFF is a meachanism to discard RX data in the driver if
the data is not needed by the application. It can be used when playing
mesages, but not recording or with unidirectional protocols.

Signed-off-by: Karsten Keil <kkeil@linux-pingi.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 13 insertions, 1 deletions

diff --git a/drivers/isdn/mISDN/hwchannel.c b/drivers/isdn/mISDN/hwchannel.c
index e541b65f68ba..ef34fd40867c 100644
--- a/drivers/isdn/mISDN/hwchannel.c
+++ b/drivers/isdn/mISDN/hwchannel.c
@@ -142,6 +142,8 @@ mISDN_clear_bchannel(struct bchannel *ch)
         test_and_clear_bit(FLG_ACTIVE, &ch->Flags);
         test_and_clear_bit(FLG_FILLEMPTY, &ch->Flags);
         test_and_clear_bit(FLG_TX_EMPTY, &ch->Flags);
+        test_and_clear_bit(FLG_RX_OFF, &ch->Flags);
+        ch->dropcnt = 0;
         ch->minlen = ch->init_minlen;
         ch->next_minlen = ch->init_minlen;
         ch->maxlen = ch->init_maxlen;
@@ -167,7 +169,8 @@ mISDN_ctrl_bchannel(struct bchannel *bch, struct mISDN_ctrl_req *cq)
 
         switch (cq->op) {
         case MISDN_CTRL_GETOP:
-                cq->op = MISDN_CTRL_RX_BUFFER | MISDN_CTRL_FILL_EMPTY;
+                cq->op = MISDN_CTRL_RX_BUFFER | MISDN_CTRL_FILL_EMPTY |
+                         MISDN_CTRL_RX_OFF;
                 break;
         case MISDN_CTRL_FILL_EMPTY:
                 if (cq->p1) {
@@ -177,6 +180,15 @@ mISDN_ctrl_bchannel(struct bchannel *bch, struct mISDN_ctrl_req *cq)
                         test_and_clear_bit(FLG_FILLEMPTY, &bch->Flags);
                 }
                 break;
+        case MISDN_CTRL_RX_OFF:
+                /* read back dropped byte count */
+                cq->p2 = bch->dropcnt;
+                if (cq->p1)
+                        test_and_set_bit(FLG_RX_OFF, &bch->Flags);
+                else
+                        test_and_clear_bit(FLG_RX_OFF, &bch->Flags);
+                bch->dropcnt = 0;
+                break;
         case MISDN_CTRL_RX_BUFFER:
                 if (cq->p2 > MISDN_CTRL_RX_SIZE_IGNORE)
                         bch->next_maxlen = cq->p2;