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>

10 files changed, 67 insertions, 13 deletions

diff --git a/drivers/isdn/hardware/mISDN/avmfritz.c b/drivers/isdn/hardware/mISDN/avmfritz.c
index c6fa505a1d1..c08fc605e56 100644
--- a/drivers/isdn/hardware/mISDN/avmfritz.c
+++ b/drivers/isdn/hardware/mISDN/avmfritz.c
@@ -408,13 +408,18 @@ hdlc_empty_fifo(struct bchannel *bch, int count)
 	struct fritzcard *fc = bch->hw;
 
 	pr_debug("%s: %s %d\n", fc->name, __func__, count);
-	cnt = bchannel_get_rxbuf(bch, count);
-	if (cnt < 0) {
-		pr_warning("%s.B%d: No bufferspace for %d bytes\n",
-			   fc->name, bch->nr, count);
-		return;
+	if (test_bit(FLG_RX_OFF, &bch->Flags)) {
+		p = NULL;
+		bch->dropcnt += count;
+	} else {
+		cnt = bchannel_get_rxbuf(bch, count);
+		if (cnt < 0) {
+			pr_warning("%s.B%d: No bufferspace for %d bytes\n",
+				   fc->name, bch->nr, count);
+			return;
+		}
+		p = skb_put(bch->rx_skb, count);
 	}
-	p = skb_put(bch->rx_skb, count);
 	ptr = (u32 *)p;
 	if (fc->type == AVM_FRITZ_PCIV2)
 		addr = fc->addr + (bch->nr == 2 ?
@@ -426,11 +431,13 @@ hdlc_empty_fifo(struct bchannel *bch, int count)
 	cnt = 0;
 	while (cnt < count) {
 		val = le32_to_cpu(inl(addr));
-		put_unaligned(val, ptr);
-		ptr++;
+		if (p) {
+			put_unaligned(val, ptr);
+			ptr++;
+		}
 		cnt += 4;
 	}
-	if (debug & DEBUG_HW_BFIFO) {
+	if (p && (debug & DEBUG_HW_BFIFO)) {
 		snprintf(fc->log, LOG_SIZE, "B%1d-recv %s %d ",
 			 bch->nr, fc->name, count);
 		print_hex_dump_bytes(fc->log, DUMP_PREFIX_OFFSET, p, count);
diff --git a/drivers/isdn/hardware/mISDN/hfcmulti.c b/drivers/isdn/hardware/mISDN/hfcmulti.c
index db9b0451982..5e402cf2e79 100644
--- a/drivers/isdn/hardware/mISDN/hfcmulti.c
+++ b/drivers/isdn/hardware/mISDN/hfcmulti.c
@@ -2224,8 +2224,11 @@ next_frame:
 	HFC_wait_nodebug(hc);
 
 	/* ignore if rx is off BUT change fifo (above) to start pending TX */
-	if (hc->chan[ch].rx_off)
+	if (hc->chan[ch].rx_off) {
+		if (bch)
+			bch->dropcnt += poll; /* not exact but fair enough */
 		return;
+	}
 
 	if (dch || test_bit(FLG_HDLC, &bch->Flags)) {
 		f1 = HFC_inb_nodebug(hc, A_F1);
@@ -3575,10 +3578,10 @@ channel_bctrl(struct bchannel *bch, struct mISDN_ctrl_req *cq)
 	switch (cq->op) {
 	case MISDN_CTRL_GETOP:
 		ret = mISDN_ctrl_bchannel(bch, cq);
-		cq->op |= MISDN_CTRL_HFC_OP | MISDN_CTRL_HW_FEATURES_OP |
-			  MISDN_CTRL_RX_OFF;
+		cq->op |= MISDN_CTRL_HFC_OP | MISDN_CTRL_HW_FEATURES_OP;
 		break;
 	case MISDN_CTRL_RX_OFF: /* turn off / on rx stream */
+		ret = mISDN_ctrl_bchannel(bch, cq);
 		hc->chan[bch->slot].rx_off = !!cq->p1;
 		if (!hc->chan[bch->slot].rx_off) {
 			/* reset fifo on rx on */
diff --git a/drivers/isdn/hardware/mISDN/hfcpci.c b/drivers/isdn/hardware/mISDN/hfcpci.c
index 1bd8bc7eb5c..81363ffa535 100644
--- a/drivers/isdn/hardware/mISDN/hfcpci.c
+++ b/drivers/isdn/hardware/mISDN/hfcpci.c
@@ -572,6 +572,11 @@ hfcpci_empty_fifo_trans(struct bchannel *bch, struct bzfifo *rxbz,
 	fcnt_tx = B_FIFO_SIZE - fcnt_tx;
 	/* remaining bytes to send (bytes in tx-fifo) */
 
+	if (test_bit(FLG_RX_OFF, &bch->Flags)) {
+		bch->dropcnt += fcnt_rx;
+		*z2r = cpu_to_le16(new_z2);
+		return;
+	}
 	maxlen = bchannel_get_rxbuf(bch, fcnt_rx);
 	if (maxlen < 0) {
 		pr_warning("B%d: No bufferspace for %d bytes\n",
diff --git a/drivers/isdn/hardware/mISDN/hfcsusb.c b/drivers/isdn/hardware/mISDN/hfcsusb.c
index b539b10d6f3..83206e453d4 100644
--- a/drivers/isdn/hardware/mISDN/hfcsusb.c
+++ b/drivers/isdn/hardware/mISDN/hfcsusb.c
@@ -842,6 +842,11 @@ hfcsusb_rx_frame(struct usb_fifo *fifo, __u8 *data, unsigned int len,
 		hdlc = 1;
 	}
 	if (fifo->bch) {
+		if (test_bit(FLG_RX_OFF, &fifo->bch->Flags)) {
+			fifo->bch->dropcnt += len;
+			spin_unlock(&hw->lock);
+			return;
+		}
 		maxlen = bchannel_get_rxbuf(fifo->bch, len);
 		rx_skb = fifo->bch->rx_skb;
 		if (maxlen < 0) {
diff --git a/drivers/isdn/hardware/mISDN/mISDNipac.c b/drivers/isdn/hardware/mISDN/mISDNipac.c
index 374a17751ff..752e0825591 100644
--- a/drivers/isdn/hardware/mISDN/mISDNipac.c
+++ b/drivers/isdn/hardware/mISDN/mISDNipac.c
@@ -936,6 +936,11 @@ hscx_empty_fifo(struct hscx_hw *hscx, u8 count)
 	int maxlen;
 
 	pr_debug("%s: B%1d %d\n", hscx->ip->name, hscx->bch.nr, count);
+	if (test_bit(FLG_RX_OFF, &hscx->bch.Flags)) {
+		hscx->bch.dropcnt += count;
+		hscx_cmdr(hscx, 0x80); /* RMC */
+		return;
+	}
 	maxlen = bchannel_get_rxbuf(&hscx->bch, count);
 	if (maxlen < 0) {
 		hscx_cmdr(hscx, 0x80); /* RMC */
diff --git a/drivers/isdn/hardware/mISDN/mISDNisar.c b/drivers/isdn/hardware/mISDN/mISDNisar.c
index 901be3257a7..be5973ded6d 100644
--- a/drivers/isdn/hardware/mISDN/mISDNisar.c
+++ b/drivers/isdn/hardware/mISDN/mISDNisar.c
@@ -429,6 +429,11 @@ isar_rcv_frame(struct isar_ch *ch)
 		ch->is->write_reg(ch->is->hw, ISAR_IIA, 0);
 		return;
 	}
+	if (test_bit(FLG_RX_OFF, &ch->bch.Flags)) {
+		ch->bch.dropcnt += ch->is->clsb;
+		ch->is->write_reg(ch->is->hw, ISAR_IIA, 0);
+		return;
+	}
 	switch (ch->bch.state) {
 	case ISDN_P_NONE:
 		pr_debug("%s: ISAR protocol 0 spurious IIS_RDATA %x/%x/%x\n",
diff --git a/drivers/isdn/hardware/mISDN/netjet.c b/drivers/isdn/hardware/mISDN/netjet.c
index aa95cc7d32f..c3e3e768627 100644
--- a/drivers/isdn/hardware/mISDN/netjet.c
+++ b/drivers/isdn/hardware/mISDN/netjet.c
@@ -386,6 +386,10 @@ read_dma(struct tiger_ch *bc, u32 idx, int cnt)
 			bc->bch.nr, idx);
 	}
 	bc->lastrx = idx;
+	if (test_bit(FLG_RX_OFF, &bc->bch.Flags)) {
+		bc->bch.dropcnt += cnt;
+		return;
+	}
 	stat = bchannel_get_rxbuf(&bc->bch, cnt);
 	/* only transparent use the count here, HDLC overun is detected later */
 	if (stat == ENOMEM) {
diff --git a/drivers/isdn/hardware/mISDN/w6692.c b/drivers/isdn/hardware/mISDN/w6692.c
index 183181f0192..26a86b84609 100644
--- a/drivers/isdn/hardware/mISDN/w6692.c
+++ b/drivers/isdn/hardware/mISDN/w6692.c
@@ -475,6 +475,11 @@ W6692_empty_Bfifo(struct w6692_ch *wch, int count)
 			skb_trim(wch->bch.rx_skb, 0);
 		return;
 	}
+	if (test_bit(FLG_RX_OFF, &wch->bch.Flags)) {
+		wch->bch.dropcnt += count;
+		WriteW6692B(wch, W_B_CMDR, W_B_CMDR_RACK | W_B_CMDR_RACT);
+		return;
+	}
 	maxlen = bchannel_get_rxbuf(&wch->bch, count);
 	if (maxlen < 0) {
 		WriteW6692B(wch, W_B_CMDR, W_B_CMDR_RACK | W_B_CMDR_RACT);
diff --git a/drivers/isdn/mISDN/hwchannel.c b/drivers/isdn/mISDN/hwchannel.c
index e541b65f68b..ef34fd40867 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;
diff --git a/include/linux/mISDNhw.h b/include/linux/mISDNhw.h
index 62118421656..d0752eca9b4 100644
--- a/include/linux/mISDNhw.h
+++ b/include/linux/mISDNhw.h
@@ -73,6 +73,8 @@
 #define FLG_LL_CONN		25
 #define FLG_DTMFSEND		26
 #define FLG_TX_EMPTY		27
+/* stop sending received data upstream */
+#define FLG_RX_OFF		28
 /* workq events */
 #define FLG_RECVQUEUE		30
 #define	FLG_PHCHANGE		31
@@ -173,6 +175,7 @@ struct bchannel {
 	int			err_crc;
 	int			err_tx;
 	int			err_rx;
+	int			dropcnt;
 };
 
 extern int	mISDN_initdchannel(struct dchannel *, int, void *);