mISDN: Implement MISDN_CTRL_FILL_EMPTY for more drivers

MISDN_CTRL_FILL_EMPTY is a meachanism to send a fixed value (normally silence)
as long no data from upper layers is available. It can be used when recording
voice messages 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, 28 insertions, 16 deletions

diff --git a/drivers/isdn/hardware/mISDN/mISDNipac.c b/drivers/isdn/hardware/mISDN/mISDNipac.c
index 3e71a5ef4bbc..374a17751ffb 100644
--- a/drivers/isdn/hardware/mISDN/mISDNipac.c
+++ b/drivers/isdn/hardware/mISDN/mISDNipac.c
@@ -969,22 +969,28 @@ hscx_fill_fifo(struct hscx_hw *hscx)
         int count, more;
         u8 *p;
 
-        if (!hscx->bch.tx_skb)
-                return;
-        count = hscx->bch.tx_skb->len - hscx->bch.tx_idx;
-        if (count <= 0)
-                return;
-        p = hscx->bch.tx_skb->data + hscx->bch.tx_idx;
-
-        more = test_bit(FLG_TRANSPARENT, &hscx->bch.Flags) ? 1 : 0;
-        if (count > hscx->fifo_size) {
+        if (!hscx->bch.tx_skb) {
+                if (!test_bit(FLG_TX_EMPTY, &hscx->bch.Flags))
+                        return;
                 count = hscx->fifo_size;
                 more = 1;
-        }
-        pr_debug("%s: B%1d %d/%d/%d\n", hscx->ip->name, hscx->bch.nr, count,
-                 hscx->bch.tx_idx, hscx->bch.tx_skb->len);
-        hscx->bch.tx_idx += count;
+                p = hscx->log;
+                memset(p, hscx->bch.fill[0], count);
+        } else {
+                count = hscx->bch.tx_skb->len - hscx->bch.tx_idx;
+                if (count <= 0)
+                        return;
+                p = hscx->bch.tx_skb->data + hscx->bch.tx_idx;
 
+                more = test_bit(FLG_TRANSPARENT, &hscx->bch.Flags) ? 1 : 0;
+                if (count > hscx->fifo_size) {
+                        count = hscx->fifo_size;
+                        more = 1;
+                }
+                pr_debug("%s: B%1d %d/%d/%d\n", hscx->ip->name, hscx->bch.nr,
+                         count, hscx->bch.tx_idx, hscx->bch.tx_skb->len);
+                hscx->bch.tx_idx += count;
+        }
         if (hscx->ip->type & IPAC_TYPE_IPACX)
                 hscx->ip->write_fifo(hscx->ip->hw,
                                      hscx->off + IPACX_XFIFOB, p, count);
@@ -995,7 +1001,7 @@ hscx_fill_fifo(struct hscx_hw *hscx)
         }
         hscx_cmdr(hscx, more ? 0x08 : 0x0a);
 
-        if (hscx->bch.debug & DEBUG_HW_BFIFO) {
+        if (hscx->bch.tx_skb && (hscx->bch.debug & DEBUG_HW_BFIFO)) {
                 snprintf(hscx->log, 64, "B%1d-send %s %d ",
                          hscx->bch.nr, hscx->ip->name, count);
                 print_hex_dump_bytes(hscx->log, DUMP_PREFIX_OFFSET, p, count);
@@ -1010,8 +1016,12 @@ hscx_xpr(struct hscx_hw *hx)
         } else {
                 if (hx->bch.tx_skb)
                         dev_kfree_skb(hx->bch.tx_skb);
-                if (get_next_bframe(&hx->bch))
+                if (get_next_bframe(&hx->bch)) {
                         hscx_fill_fifo(hx);
+                        test_and_clear_bit(FLG_TX_EMPTY, &hx->bch.Flags);
+                } else if (test_bit(FLG_TX_EMPTY, &hx->bch.Flags)) {
+                        hscx_fill_fifo(hx);
+                }
         }
 }
 
@@ -1128,7 +1138,9 @@ ipac_irq(struct hscx_hw *hx, u8 ista)
 
         if (istab & IPACX_B_XDU) {
                 if (test_bit(FLG_TRANSPARENT, &hx->bch.Flags)) {
-                        hscx_fill_fifo(hx);
+                        if (test_bit(FLG_FILLEMPTY, &hx->bch.Flags))
+                                test_and_set_bit(FLG_TX_EMPTY, &hx->bch.Flags);
+                        hscx_xpr(hx);
                         return;
                 }
                 pr_debug("%s: B%1d XDU error at len %d\n", hx->ip->name,