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>

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);

drivers/isdn/hardware/mISDN/hfcmulti.c

@@ -2224,8 +2224,11 @@ hfcmulti_rx(struct hfc_multi *hc, int ch)
 	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 */

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",

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) {

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 */

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",

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) {

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);

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;

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 *);