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>

1 files changed, 35 insertions, 10 deletions

diff --git a/drivers/isdn/hardware/mISDN/hfcmulti.c b/drivers/isdn/hardware/mISDN/hfcmulti.c
index ff5ec3c..3fc2e9d 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);