Reduce latency by checking FIFO for samples in start
Remove flags by testing register shadow Handle apparent pending interrupt after interrupts disabled.
This commit is contained in:
Peter Dufault
parent
e2c89acf82
commit
34688a8bd5
@ -58,6 +58,12 @@
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#include <machine/clock.h>
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/* Miniumum timeout:
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*/
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#ifndef LABPC_MIN_TMO
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#define LABPC_MIN_TMO (hz)
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#endif
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#ifndef LABPC_DEFAULT_HERZ
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#define LABPC_DEFAULT_HERZ 500
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#endif
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@ -116,6 +122,8 @@ struct ctlr
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u_char *data;
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u_char *data_end;
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long tmo; /* Timeout in Herz */
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long min_tmo; /* Timeout in Herz */
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int cleared_intr;
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int gains[8];
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@ -154,7 +162,7 @@ struct ctlr **labpcs; /* XXX: Should be dynamic */
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*/
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#define CR_EXPR(LABPC, CR, EXPR) do { \
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(LABPC)->cr_image[CR - 1] EXPR ; \
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loutb((LABPC)->base + (CR == 4 ? 0x0F : CR - 1), (LABPC)->cr_image[(CR - 1)]); \
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loutb(((LABPC)->base + ( (CR == 4) ? (0x0F) : (CR - 1))), ((LABPC)->cr_image[(CR - 1)])); \
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} while (0)
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#define CR_CLR(LABPC, CR) CR_EXPR(LABPC, CR, &=0)
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@ -267,9 +275,10 @@ struct isa_driver labpcdriver =
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static void
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bp_done(struct buf *bp, int err)
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{
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if (err)
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bp->b_error = err;
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if (err || bp->b_resid)
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{
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bp->b_error = err;
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bp->b_flags |= B_ERROR;
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}
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@ -279,7 +288,7 @@ bp_done(struct buf *bp, int err)
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static void tmo_stop(void *p);
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static void
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done_and_dequeu(struct ctlr *ctlr, struct buf *bp, int err)
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done_and_start_next(struct ctlr *ctlr, struct buf *bp, int err)
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{
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static void start(struct ctlr *ctlr);
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@ -479,6 +488,8 @@ int labpcattach(struct isa_device *dev)
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reset(ctlr);
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labpc_registerdev(dev);
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ctlr->min_tmo = LABPC_MIN_TMO;
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ctlr->dcr_val = 0x80;
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ctlr->dcr_is = 0x80;
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loutb(DCR(ctlr), ctlr->dcr_val);
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@ -531,7 +542,8 @@ ad_start(struct ctlr *ctlr, long count)
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trigger(ctlr);
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}
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ctlr->tmo = ((count + 16) * (long)ctlr->sample_us * hz) / 1000000 + 1;
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ctlr->tmo = ((count + 16) * (long)ctlr->sample_us * hz) / 1000000 +
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ctlr->min_tmo;
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}
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static void
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@ -576,7 +588,8 @@ ad_interval_start(struct ctlr *ctlr, long count)
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* the number of channels being sampled plus the sample period.
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*/
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ctlr->tmo = ((n_frames + 16) *
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((long)ctlr->sample_us + (chan + 1 ) * 2 ) * hz) / 1000000 + 1;
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((long)ctlr->sample_us + (chan + 1 ) * 2 ) * hz) / 1000000 +
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ctlr->min_tmo;
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}
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static void
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@ -590,29 +603,32 @@ tmo_stop(void *p)
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{
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struct ctlr *ctlr = (struct ctlr *)p;
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struct buf *bp;
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int s = spltty();
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if (ctlr == 0)
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{
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printf("labpc?: Null ctlr struct?\n");
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splx(s);
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return;
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}
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printf("labpc%d: timeout\n", ctlr->unit);
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printf("labpc%d: timeout", ctlr->unit);
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(*ctlr->stop)(ctlr);
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bp = ctlr->start_queue.b_actf;
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if (bp == 0) {
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printf("labpc%d timeout: Null bp.\n", ctlr->unit);
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/* No more data being transferred.
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*/
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printf(", Null bp.\n");
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splx(s);
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return;
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}
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printf("\n");
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done_and_dequeu(ctlr, bp, ETIMEDOUT);
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done_and_start_next(ctlr, bp, ETIMEDOUT);
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splx(s);
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}
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@ -620,53 +636,69 @@ static void ad_intr(struct ctlr *ctlr)
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{
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u_char status;
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if (ctlr->cr_image[2] == 0)
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{
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if (ctlr->cleared_intr)
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{
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ctlr->cleared_intr = 0;
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return;
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}
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printf("ad_intr (should not happen) interrupt with interrupts off\n");
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printf("status %x, cr3 %x\n", inb(STATUS(ctlr)), ctlr->cr_image[2]);
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return;
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}
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while ( (status = (inb(STATUS(ctlr)) & (DAVAIL|OVERRUN|OVERFLOW)) ) )
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{
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if ((status & (OVERRUN|OVERFLOW)))
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{
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struct buf *bp = ctlr->start_queue.b_actf;
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printf("ad_intr: error: data %p, status %x",
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ctlr->data, status);
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printf("ad_intr: error: bp %0p, data %0p, status %x",
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bp, ctlr->data, status);
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if (status & OVERRUN)
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printf(" OVERRUN");
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printf(" Conversion overrun (multiple A-D trigger)");
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if (status & OVERFLOW)
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printf(" OVERFLOW");
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printf(" FIFO overflow");
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printf("\n");
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(*ctlr->stop)(ctlr);
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/* There may not be a bp if the interrupt went off between
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* frames, that is, when no process was ready to receive and
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* we are using a mode that is driven by the sample clock.
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*/
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if (bp)
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{
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done_and_dequeu(ctlr, bp, EIO);
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done_and_start_next(ctlr, bp, EIO);
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return;
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}
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else
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{
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printf("ad_intr: (should not happen) error between records\n");
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ctlr->err = status; /* Set overrun condition */
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return;
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}
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}
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else /* FIFO interrupt */
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{
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struct buf *bp = ctlr->start_queue.b_actf;
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if (ctlr->data)
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{
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*ctlr->data++ = inb(ADFIFO(ctlr));
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if (ctlr->data == ctlr->data_end) /* Normal completion */
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{
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struct buf *bp = ctlr->start_queue.b_actf;
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done_and_dequeu(ctlr, bp, 0);
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done_and_start_next(ctlr, bp, 0);
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return;
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}
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}
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else /* Interrupt with no where to put the data. */
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{
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printf("ad_intr: (should not happen) dropped input.\n");
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(void)inb(ADFIFO(ctlr));
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printf("bp %0p, status %x, cr3 %x\n", bp, status,
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ctlr->cr_image[2]);
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ctlr->err = DROPPED_INPUT;
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return;
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}
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@ -680,13 +712,13 @@ void labpcintr(int unit)
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(*ctlr->intr)(ctlr);
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}
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/* mode_change_needed: Return whether or not we can open again, or
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/* lockout_multiple_opens: Return whether or not we can open again, or
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* if the new mode is inconsistent with an already opened mode.
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* We only permit multiple opens for digital I/O now.
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*/
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static int
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mode_change_needed(dev_t current, dev_t next)
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lockout_multiple_open(dev_t current, dev_t next)
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{
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return ! (DIGITAL(current) && DIGITAL(next));
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}
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@ -722,10 +754,8 @@ labpcopen(dev_t dev, int flags, int fmt, struct proc *p)
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ctlr->intr = null_intr;
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ctlr->starter = null_start;
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ctlr->stop = null_stop;
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CR_EXPR(ctlr, 3, |= ERRINTEN);
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}
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else if (mode_change_needed(ctlr->dev, dev))
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else if (lockout_multiple_open(ctlr->dev, dev))
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return EBUSY;
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return 0;
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@ -757,7 +787,8 @@ start(struct ctlr *ctlr)
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* place to put the data. We have to get back to
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* reading before the FIFO overflows.
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*/
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CR_EXPR(ctlr, 3, &= ~FIFOINTEN);
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CR_EXPR(ctlr, 3, &= ~(FIFOINTEN|ERRINTEN));
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ctlr->cleared_intr = 1;
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ctlr->start_queue.b_active = 0;
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return;
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}
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@ -765,19 +796,32 @@ start(struct ctlr *ctlr)
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ctlr->data = (u_char *)bp->b_un.b_addr;
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ctlr->data_end = ctlr->data + bp->b_bcount;
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if (!FIFOINTENABLED(ctlr)) /* We can store the data again */
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if (ctlr->err)
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{
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if (ctlr->err) /* Dropped input between records */
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{
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done_and_dequeu(ctlr, bp, ENOSPC);
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return;
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}
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CR_EXPR(ctlr, 3, |= FIFOINTEN);
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printf("labpc start: (should not happen) error between records.\n");
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done_and_start_next(ctlr, bp, EIO);
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return;
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}
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ctlr->err = 0;
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if (ctlr->data == 0)
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{
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printf("labpc start: (should not happen) NULL data pointer.\n");
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done_and_start_next(ctlr, bp, EIO);
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return;
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}
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(*ctlr->starter)(ctlr, bp->b_bcount);
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if (!FIFOINTENABLED(ctlr)) /* We can store the data again */
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{
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CR_EXPR(ctlr, 3, |= (FIFOINTEN|ERRINTEN));
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/* Don't wait for the interrupts to fill things up.
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*/
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(*ctlr->intr)(ctlr);
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}
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timeout(tmo_stop, ctlr, ctlr->tmo);
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}
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