mISDN: Add feature via MISDN_CTRL_FILL_EMPTY to fill fifo if empty

This prevents underrun of fifo when filled and in case of an underrun it
prevents subsequent underruns due to jitter.
Improve dsp, so buffers are kept filled with a certain delay, so moderate
jitter will not cause underrun all the time -> the audio quality is highly
improved. tones are not interrupted by gaps anymore, except when CPU is
stalling or in high load.

Signed-off-by: Andreas Eversberg <andreas@eversberg.eu>
Signed-off-by: Karsten Keil <kkeil@suse.de>

7 files changed, 151 insertions, 33 deletions

diff --git a/drivers/isdn/hardware/mISDN/hfc_multi.h b/drivers/isdn/hardware/mISDN/hfc_multi.h
index 6d74951a1797..4aa6a8b41f50 100644
--- a/drivers/isdn/hardware/mISDN/hfc_multi.h
+++ b/drivers/isdn/hardware/mISDN/hfc_multi.h
@@ -9,6 +9,7 @@
 #define DEBUG_HFCMULTI_MODE     0x00100000
 #define DEBUG_HFCMULTI_MSG      0x00200000
 #define DEBUG_HFCMULTI_STATE    0x00400000
+#define DEBUG_HFCMULTI_FILL     0x00800000
 #define DEBUG_HFCMULTI_SYNC     0x01000000
 #define DEBUG_HFCMULTI_DTMF     0x02000000
 #define DEBUG_HFCMULTI_LOCK     0x80000000
@@ -166,6 +167,8 @@ struct hfc_multi {
 
         u_long          chip;   /* chip configuration */
         int             masterclk; /* port that provides master clock -1=off */
+        unsigned char   silence;/* silence byte */
+        unsigned char   silence_data[128];/* silence block */
         int             dtmf;   /* flag that dtmf is currently in process */
         int             Flen;   /* F-buffer size */
         int             Zlen;   /* Z-buffer size (must be int for calculation)*/
diff --git a/drivers/isdn/hardware/mISDN/hfc_pci.h b/drivers/isdn/hardware/mISDN/hfc_pci.h
index 5783d22a18fe..fd9241ab1802 100644
--- a/drivers/isdn/hardware/mISDN/hfc_pci.h
+++ b/drivers/isdn/hardware/mISDN/hfc_pci.h
@@ -27,6 +27,7 @@
  */
 #define HFCPCI_BTRANS_THRESHOLD 128
 #define HFCPCI_BTRANS_MAX       256
+#define HFCPCI_FILLEMPTY        64
 #define HFCPCI_BTRANS_THRESMASK 0x00
 
 /* defines for PCI config */
diff --git a/drivers/isdn/hardware/mISDN/hfcmulti.c b/drivers/isdn/hardware/mISDN/hfcmulti.c
index ff5ec3cbeb77..3fc2e9d95341 100644
--- a/drivers/isdn/hardware/mISDN/hfcmulti.c
+++ b/drivers/isdn/hardware/mISDN/hfcmulti.c
@@ -180,7 +180,6 @@ static int nt_t1_count[] = { 3840, 1920, 960, 480, 240, 120, 60, 30  };
 #define CLKDEL_TE       0x0f    /* CLKDEL in TE mode */
 #define CLKDEL_NT       0x6c    /* CLKDEL in NT mode
                                    (0x60 MUST be included!) */
-static u_char silence = 0xff;   /* silence by LAW */
 
 #define DIP_4S  0x1             /* DIP Switches for Beronet 1S/2S/4S cards */
 #define DIP_8S  0x2             /* DIP Switches for Beronet 8S+ cards */
@@ -1975,6 +1974,17 @@ next_frame:
                 return; /* no data */
         }
 
+        /* "fill fifo if empty" feature */
+        if (bch && test_bit(FLG_FILLEMPTY, &bch->Flags)
+                && !test_bit(FLG_HDLC, &bch->Flags) && z2 == z1) {
+                if (debug & DEBUG_HFCMULTI_FILL)
+                        printk(KERN_DEBUG "%s: buffer empty, so we have "
+                                "underrun\n", __func__);
+                /* fill buffer, to prevent future underrun */
+                hc->write_fifo(hc, hc->silence_data, poll >> 1);
+                Zspace -= (poll >> 1);
+        }
+
         /* if audio data and connected slot */
         if (bch && (!test_bit(FLG_HDLC, &bch->Flags)) && (!*txpending)
                 && slot_tx >= 0) {
@@ -2011,7 +2021,6 @@ next_frame:
                         __func__, hc->id + 1, ch, Zspace, z1, z2, ii-i, len-i,
                         temp ? "HDLC":"TRANS");
 
-
         /* Have to prep the audio data */
         hc->write_fifo(hc, d, ii - i);
         *idxp = ii;
@@ -2050,7 +2059,7 @@ next_frame:
          * no more data at all. this prevents sending an undefined value.
          */
         if (bch && test_bit(FLG_TRANSPARENT, &bch->Flags))
-                HFC_outb_nodebug(hc, A_FIFO_DATA0_NOINC, silence);
+                HFC_outb_nodebug(hc, A_FIFO_DATA0_NOINC, hc->silence);
 }
 
 
@@ -2932,7 +2941,7 @@ mode_hfcmulti(struct hfc_multi *hc, int ch, int protocol, int slot_tx,
                         HFC_outb(hc, R_INC_RES_FIFO, V_RES_F);
                         HFC_wait(hc);
                         /* tx silence */
-                        HFC_outb_nodebug(hc, A_FIFO_DATA0_NOINC, silence);
+                        HFC_outb_nodebug(hc, A_FIFO_DATA0_NOINC, hc->silence);
                         HFC_outb(hc, R_SLOT, (((ch / 4) * 8) +
                             ((ch % 4) * 4)) << 1);
                         HFC_outb(hc, A_SL_CFG, 0x80 | 0x20 | (ch << 1));
@@ -2947,7 +2956,7 @@ mode_hfcmulti(struct hfc_multi *hc, int ch, int protocol, int slot_tx,
                         HFC_outb(hc, R_INC_RES_FIFO, V_RES_F);
                         HFC_wait(hc);
                         /* tx silence */
-                        HFC_outb_nodebug(hc, A_FIFO_DATA0_NOINC, silence);
+                        HFC_outb_nodebug(hc, A_FIFO_DATA0_NOINC, hc->silence);
                         /* enable RX fifo */
                         HFC_outb(hc, R_FIFO, (ch<<1)|1);
                         HFC_wait(hc);
@@ -3439,7 +3448,7 @@ channel_bctrl(struct bchannel *bch, struct mISDN_ctrl_req *cq)
         switch (cq->op) {
         case MISDN_CTRL_GETOP:
                 cq->op = MISDN_CTRL_HFC_OP | MISDN_CTRL_HW_FEATURES_OP
-                        | MISDN_CTRL_RX_OFF;
+                        | MISDN_CTRL_RX_OFF | MISDN_CTRL_FILL_EMPTY;
                 break;
         case MISDN_CTRL_RX_OFF: /* turn off / on rx stream */
                 hc->chan[bch->slot].rx_off = !!cq->p1;
@@ -3454,6 +3463,12 @@ channel_bctrl(struct bchannel *bch, struct mISDN_ctrl_req *cq)
                         printk(KERN_DEBUG "%s: RX_OFF request (nr=%d off=%d)\n",
                             __func__, bch->nr, hc->chan[bch->slot].rx_off);
                 break;
+        case MISDN_CTRL_FILL_EMPTY: /* fill fifo, if empty */
+                test_and_set_bit(FLG_FILLEMPTY, &bch->Flags);
+                if (debug & DEBUG_HFCMULTI_MSG)
+                        printk(KERN_DEBUG "%s: FILL_EMPTY request (nr=%d "
+                                "off=%d)\n", __func__, bch->nr, !!cq->p1);
+                break;
         case MISDN_CTRL_HW_FEATURES: /* fill features structure */
                 if (debug & DEBUG_HFCMULTI_MSG)
                         printk(KERN_DEBUG "%s: HW_FEATURE request\n",
@@ -3970,6 +3985,7 @@ open_bchannel(struct hfc_multi *hc, struct dchannel *dch,
         }
         if (test_and_set_bit(FLG_OPEN, &bch->Flags))
                 return -EBUSY; /* b-channel can be only open once */
+        test_and_clear_bit(FLG_FILLEMPTY, &bch->Flags);
         bch->ch.protocol = rq->protocol;
         hc->chan[ch].rx_off = 0;
         rq->ch = &bch->ch;
@@ -4806,6 +4822,7 @@ hfcmulti_init(struct pci_dev *pdev, const struct pci_device_id *ent)
         struct hfc_multi        *hc;
         u_long          flags;
         u_char          dips = 0, pmj = 0; /* dip settings, port mode Jumpers */
+        int             i;
 
         if (HFC_cnt >= MAX_CARDS) {
                 printk(KERN_ERR "too many cards (max=%d).\n",
@@ -4839,11 +4856,11 @@ hfcmulti_init(struct pci_dev *pdev, const struct pci_device_id *ent)
         hc->id = HFC_cnt;
         hc->pcm = pcm[HFC_cnt];
         hc->io_mode = iomode[HFC_cnt];
-        if (dslot[HFC_cnt] < 0) {
+        if (dslot[HFC_cnt] < 0 && hc->type == 1) {
                 hc->dslot = 0;
                 printk(KERN_INFO "HFC-E1 card has disabled D-channel, but "
                         "31 B-channels\n");
-        } if (dslot[HFC_cnt] > 0 && dslot[HFC_cnt] < 32) {
+        } if (dslot[HFC_cnt] > 0 && dslot[HFC_cnt] < 32 && hc->type == 1) {
                 hc->dslot = dslot[HFC_cnt];
                 printk(KERN_INFO "HFC-E1 card has alternating D-channel on "
                         "time slot %d\n", dslot[HFC_cnt]);
@@ -4854,9 +4871,17 @@ hfcmulti_init(struct pci_dev *pdev, const struct pci_device_id *ent)
         hc->masterclk = -1;
         if (type[HFC_cnt] & 0x100) {
                 test_and_set_bit(HFC_CHIP_ULAW, &hc->chip);
-                silence = 0xff; /* ulaw silence */
+                hc->silence = 0xff; /* ulaw silence */
         } else
-                silence = 0x2a; /* alaw silence */
+                hc->silence = 0x2a; /* alaw silence */
+        if ((poll >> 1) > sizeof(hc->silence_data)) {
+                printk(KERN_ERR "HFCMULTI error: silence_data too small, "
+                        "please fix\n");
+                return -EINVAL;
+        }
+        for (i = 0; i < (poll >> 1); i++)
+                hc->silence_data[i] = hc->silence;
+
         if (!(type[HFC_cnt] & 0x200))
                 test_and_set_bit(HFC_CHIP_DTMF, &hc->chip);
 
diff --git a/drivers/isdn/hardware/mISDN/hfcpci.c b/drivers/isdn/hardware/mISDN/hfcpci.c
index cd8302af40eb..80c356e5dbe1 100644
--- a/drivers/isdn/hardware/mISDN/hfcpci.c
+++ b/drivers/isdn/hardware/mISDN/hfcpci.c
@@ -751,6 +751,36 @@ hfcpci_fill_fifo(struct bchannel *bch)
                             /* fcnt contains available bytes in fifo */
                 fcnt = B_FIFO_SIZE - fcnt;
                     /* remaining bytes to send (bytes in fifo) */
+
+                /* "fill fifo if empty" feature */
+                if (test_bit(FLG_FILLEMPTY, &bch->Flags) && !fcnt) {
+                        /* printk(KERN_DEBUG "%s: buffer empty, so we have "
+                                "underrun\n", __func__); */
+                        /* fill buffer, to prevent future underrun */
+                        count = HFCPCI_FILLEMPTY;
+                        new_z1 = le16_to_cpu(*z1t) + count;
+                           /* new buffer Position */
+                        if (new_z1 >= (B_FIFO_SIZE + B_SUB_VAL))
+                                new_z1 -= B_FIFO_SIZE;  /* buffer wrap */
+                        dst = bdata + (le16_to_cpu(*z1t) - B_SUB_VAL);
+                        maxlen = (B_FIFO_SIZE + B_SUB_VAL) - le16_to_cpu(*z1t);
+                            /* end of fifo */
+                        if (bch->debug & DEBUG_HW_BFIFO)
+                                printk(KERN_DEBUG "hfcpci_FFt fillempty "
+                                    "fcnt(%d) maxl(%d) nz1(%x) dst(%p)\n",
+                                    fcnt, maxlen, new_z1, dst);
+                        fcnt += count;
+                        if (maxlen > count)
+                                maxlen = count;         /* limit size */
+                        memset(dst, 0x2a, maxlen);      /* first copy */
+                        count -= maxlen;                /* remaining bytes */
+                        if (count) {
+                                dst = bdata;            /* start of buffer */
+                                memset(dst, 0x2a, count);
+                        }
+                        *z1t = cpu_to_le16(new_z1);     /* now send data */
+                }
+
 next_t_frame:
                 count = bch->tx_skb->len - bch->tx_idx;
                 /* maximum fill shall be HFCPCI_BTRANS_MAX */
@@ -1481,11 +1511,17 @@ deactivate_bchannel(struct bchannel *bch)
 static int
 channel_bctrl(struct bchannel *bch, struct mISDN_ctrl_req *cq)
 {
-        int                     ret = 0;
+        int     ret = 0;
 
         switch (cq->op) {
         case MISDN_CTRL_GETOP:
-                cq->op = 0;
+                cq->op = MISDN_CTRL_FILL_EMPTY;
+                break;
+        case MISDN_CTRL_FILL_EMPTY: /* fill fifo, if empty */
+                test_and_set_bit(FLG_FILLEMPTY, &bch->Flags);
+                if (debug & DEBUG_HW_OPEN)
+                        printk(KERN_DEBUG "%s: FILL_EMPTY request (nr=%d "
+                                "off=%d)\n", __func__, bch->nr, !!cq->p1);
                 break;
         default:
                 printk(KERN_WARNING "%s: unknown Op %x\n", __func__, cq->op);
@@ -1903,6 +1939,7 @@ open_bchannel(struct hfc_pci *hc, struct channel_req *rq)
         bch = &hc->bch[rq->adr.channel - 1];
         if (test_and_set_bit(FLG_OPEN, &bch->Flags))
                 return -EBUSY; /* b-channel can be only open once */
+        test_and_clear_bit(FLG_FILLEMPTY, &bch->Flags);
         bch->ch.protocol = rq->protocol;
         rq->ch = &bch->ch; /* TODO: E-channel */
         if (!try_module_get(THIS_MODULE))
diff --git a/drivers/isdn/mISDN/dsp.h b/drivers/isdn/mISDN/dsp.h
index 6c3fed6b8d4f..ded948069335 100644
--- a/drivers/isdn/mISDN/dsp.h
+++ b/drivers/isdn/mISDN/dsp.h
@@ -198,6 +198,7 @@ struct dsp {
         /* hardware stuff */
         struct dsp_features features;
         int             features_rx_off; /* set if rx_off is featured */
+        int             features_fill_empty; /* set if fill_empty is featured */
         int             pcm_slot_rx; /* current PCM slot (or -1) */
         int             pcm_bank_rx;
         int             pcm_slot_tx;
diff --git a/drivers/isdn/mISDN/dsp_cmx.c b/drivers/isdn/mISDN/dsp_cmx.c
index c884511e2d49..fc8ea41ae6a2 100644
--- a/drivers/isdn/mISDN/dsp_cmx.c
+++ b/drivers/isdn/mISDN/dsp_cmx.c
@@ -1168,11 +1168,18 @@ dsp_cmx_receive(struct dsp *dsp, struct sk_buff *skb)
                 dsp->rx_init = 0;
                 if (dsp->features.unordered) {
                         dsp->rx_R = (hh->id & CMX_BUFF_MASK);
-                        dsp->rx_W = (dsp->rx_R + dsp->cmx_delay)
-                                & CMX_BUFF_MASK;
+                        if (dsp->cmx_delay)
+                                dsp->rx_W = (dsp->rx_R + dsp->cmx_delay)
+                                        & CMX_BUFF_MASK;
+                        else
+                                dsp->rx_W = (dsp->rx_R + (dsp_poll >> 1))
+                                        & CMX_BUFF_MASK;
                 } else {
                         dsp->rx_R = 0;
-                        dsp->rx_W = dsp->cmx_delay;
+                        if (dsp->cmx_delay)
+                                dsp->rx_W = dsp->cmx_delay;
+                        else
+                                dsp->rx_W = dsp_poll >> 1;
                 }
         }
         /* if frame contains time code, write directly */
@@ -1190,14 +1197,20 @@ dsp_cmx_receive(struct dsp *dsp, struct sk_buff *skb)
                             "cmx_receive(dsp=%lx): UNDERRUN (or overrun the "
                             "maximum delay), adjusting read pointer! "
                             "(inst %s)\n", (u_long)dsp, dsp->name);
-                /* flush buffer */
+                /* flush rx buffer and set delay to dsp_poll / 2 */
                 if (dsp->features.unordered) {
                         dsp->rx_R = (hh->id & CMX_BUFF_MASK);
-                        dsp->rx_W = (dsp->rx_R + dsp->cmx_delay)
-                                & CMX_BUFF_MASK;
+                        if (dsp->cmx_delay)
+                                dsp->rx_W = (dsp->rx_R + dsp->cmx_delay)
+                                        & CMX_BUFF_MASK;
+                                dsp->rx_W = (dsp->rx_R + (dsp_poll >> 1))
+                                        & CMX_BUFF_MASK;
                 } else {
                         dsp->rx_R = 0;
-                        dsp->rx_W = dsp->cmx_delay;
+                        if (dsp->cmx_delay)
+                                dsp->rx_W = dsp->cmx_delay;
+                        else
+                                dsp->rx_W = dsp_poll >> 1;
                 }
                 memset(dsp->rx_buff, dsp_silence, sizeof(dsp->rx_buff));
         }
@@ -1360,8 +1373,11 @@ dsp_cmx_send_member(struct dsp *dsp, int len, s32 *c, int members)
                                 t = (t+1) & CMX_BUFF_MASK;
                                 r = (r+1) & CMX_BUFF_MASK;
                         }
-                        if (r != rr)
+                        if (r != rr) {
+                                printk(KERN_DEBUG "%s: buffer empty\n",
+                                        __func__);
                                 memset(d, dsp_silence, (rr-r)&CMX_BUFF_MASK);
+                        }
                 /* -> if echo is enabled */
                 } else {
                         /*
@@ -1704,9 +1720,10 @@ dsp_cmx_send(void *arg)
                         }
                         /*
                          * remove rx_delay only if we have delay AND we
-                         * have not preset cmx_delay
+                         * have not preset cmx_delay AND
+                         * the delay is greater dsp_poll
                          */
-                        if (delay && !dsp->cmx_delay) {
+                        if (delay > dsp_poll && !dsp->cmx_delay) {
                                 if (dsp_debug & DEBUG_DSP_CMX)
                                         printk(KERN_DEBUG
                                             "%s lowest rx_delay of %d bytes for"
@@ -1714,7 +1731,8 @@ dsp_cmx_send(void *arg)
                                             __func__, delay,
                                             dsp->name);
                                 r = dsp->rx_R;
-                                rr = (r + delay) & CMX_BUFF_MASK;
+                                rr = (r + delay - (dsp_poll >> 1))
+                                        & CMX_BUFF_MASK;
                                 /* delete rx-data */
                                 while (r != rr) {
                                         p[r] = dsp_silence;
@@ -1736,7 +1754,7 @@ dsp_cmx_send(void *arg)
                          * remove delay only if we have delay AND we
                          * have enabled tx_dejitter
                          */
-                        if (delay && dsp->tx_dejitter) {
+                        if (delay > dsp_poll && dsp->tx_dejitter) {
                                 if (dsp_debug & DEBUG_DSP_CMX)
                                         printk(KERN_DEBUG
                                             "%s lowest tx_delay of %d bytes for"
@@ -1744,7 +1762,8 @@ dsp_cmx_send(void *arg)
                                             __func__, delay,
                                             dsp->name);
                                 r = dsp->tx_R;
-                                rr = (r + delay) & CMX_BUFF_MASK;
+                                rr = (r + delay - (dsp_poll >> 1))
+                                        & CMX_BUFF_MASK;
                                 /* delete tx-data */
                                 while (r != rr) {
                                         q[r] = dsp_silence;
@@ -1797,14 +1816,13 @@ dsp_cmx_transmit(struct dsp *dsp, struct sk_buff *skb)
         ww = dsp->tx_R;
         p = dsp->tx_buff;
         d = skb->data;
-        space = ww-w;
-        if (space <= 0)
-                space += CMX_BUFF_SIZE;
+        space = (ww - w - 1) & CMX_BUFF_MASK;
         /* write-pointer should not overrun nor reach read pointer */
-        if (space-1 < skb->len)
+        if (space < skb->len) {
                 /* write to the space we have left */
-                ww = (ww - 1) & CMX_BUFF_MASK;
-        else
+                ww = (ww - 1) & CMX_BUFF_MASK; /* end one byte prior tx_R */
+                printk(KERN_DEBUG "%s: buffer overflow\n", __func__);
+        } else
                 /* write until all byte are copied */
                 ww = (w + skb->len) & CMX_BUFF_MASK;
         dsp->tx_W = ww;
diff --git a/drivers/isdn/mISDN/dsp_core.c b/drivers/isdn/mISDN/dsp_core.c
index 1dc21d803410..1d504ba954f5 100644
--- a/drivers/isdn/mISDN/dsp_core.c
+++ b/drivers/isdn/mISDN/dsp_core.c
@@ -191,6 +191,8 @@ dsp_rx_off_member(struct dsp *dsp)
         struct mISDN_ctrl_req   cq;
         int rx_off = 1;
 
+        memset(&cq, 0, sizeof(cq));
+
         if (!dsp->features_rx_off)
                 return;
 
@@ -249,6 +251,32 @@ dsp_rx_off(struct dsp *dsp)
         }
 }
 
+/* enable "fill empty" feature */
+static void
+dsp_fill_empty(struct dsp *dsp)
+{
+        struct mISDN_ctrl_req   cq;
+
+        memset(&cq, 0, sizeof(cq));
+
+        if (!dsp->ch.peer) {
+                if (dsp_debug & DEBUG_DSP_CORE)
+                        printk(KERN_DEBUG "%s: no peer, no fill_empty\n",
+                                __func__);
+                return;
+        }
+        cq.op = MISDN_CTRL_FILL_EMPTY;
+        cq.p1 = 1;
+        if (dsp->ch.peer->ctrl(dsp->ch.peer, CONTROL_CHANNEL, &cq)) {
+                printk(KERN_DEBUG "%s: CONTROL_CHANNEL failed\n",
+                        __func__);
+                return;
+        }
+        if (dsp_debug & DEBUG_DSP_CORE)
+                printk(KERN_DEBUG "%s: %s set fill_empty = 1\n",
+                        __func__, dsp->name);
+}
+
 static int
 dsp_control_req(struct dsp *dsp, struct mISDNhead *hh, struct sk_buff *skb)
 {
@@ -593,8 +621,6 @@ get_features(struct mISDNchannel *ch)
         struct dsp              *dsp = container_of(ch, struct dsp, ch);
         struct mISDN_ctrl_req   cq;
 
-        if (dsp_options & DSP_OPT_NOHARDWARE)
-                return;
         if (!ch->peer) {
                 if (dsp_debug & DEBUG_DSP_CORE)
                         printk(KERN_DEBUG "%s: no peer, no features\n",
@@ -610,6 +636,10 @@ get_features(struct mISDNchannel *ch)
         }
         if (cq.op & MISDN_CTRL_RX_OFF)
                 dsp->features_rx_off = 1;
+        if (cq.op & MISDN_CTRL_FILL_EMPTY)
+                dsp->features_fill_empty = 1;
+        if (dsp_options & DSP_OPT_NOHARDWARE)
+                return;
         if ((cq.op & MISDN_CTRL_HW_FEATURES_OP)) {
                 cq.op = MISDN_CTRL_HW_FEATURES;
                 *((u_long *)&cq.p1) = (u_long)&dsp->features;
@@ -865,6 +895,9 @@ dsp_function(struct mISDNchannel *ch,  struct sk_buff *skb)
                 if (dsp->dtmf.hardware || dsp->dtmf.software)
                         dsp_dtmf_goertzel_init(dsp);
                 get_features(ch);
+                /* enable fill_empty feature */
+                if (dsp->features_fill_empty)
+                        dsp_fill_empty(dsp);
                 /* send ph_activate */
                 hh->prim = PH_ACTIVATE_REQ;
                 if (ch->peer)