Date: Wed, 25 Oct 2006 21:11:40 GMT From: Warner Losh <imp@FreeBSD.org> To: Perforce Change Reviews <perforce@freebsd.org> Subject: PERFORCE change 108438 for review Message-ID: <200610252111.k9PLBeLx085707@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=108438 Change 108438 by imp@imp_lighthouse on 2006/10/25 21:11:20 Do interlocking on the write channel. Only one may be there. All others block. Note: non-blocking I/O will block at this point. libc_r is dead, so the need to support NBIO isn't there for our apps anymore. Affected files ... .. //depot/projects/arm/src/sys/arm/at91/at91_ssc.c#14 edit Differences ... ==== //depot/projects/arm/src/sys/arm/at91/at91_ssc.c#14 (text+ko) ==== @@ -41,6 +41,7 @@ #include <arm/at91/at91_pdcreg.h> #define MAX_BUF 1024 +#define NRX_BUF 2 struct at91_ssc_softc { @@ -51,12 +52,15 @@ struct mtx sc_mtx; /* basically a perimeter lock */ struct cdev *cdev; int flags; -#define OPENED 1 +#define OPENED 0x01 +#define WRITE_BUSY 0x02 bus_dma_tag_t tag; /* bus dma tag */ bus_dmamap_t tx_map; int txdone; uint8_t rx_buf[MAX_BUF]; - bus_dmamap_t rx_map; + uint8_t *rx_end; + bus_dmamap_t rx_map[NRX_BUF]; + int rxdone; }; static inline uint32_t @@ -120,7 +124,7 @@ at91_ssc_attach(device_t dev) { struct at91_ssc_softc *sc = device_get_softc(dev); - int err; + int err, i; sc->dev = dev; err = at91_ssc_activate(dev); @@ -150,9 +154,11 @@ err = bus_dmamap_create(sc->tag, 0, &sc->tx_map); if (err != 0) goto out; - err = bus_dmamap_create(sc->tag, 0, &sc->rx_map); - if (err != 0) - goto out; + for (i = 0; i < NRX_BUF; i++) { + err = bus_dmamap_create(sc->tag, 0, &sc->rx_map[i]); + if (err != 0) + goto out; + } sc->cdev = make_dev(&at91_ssc_cdevsw, device_get_unit(dev), UID_ROOT, GID_WHEEL, 0600, "ssc%d", device_get_unit(dev)); @@ -310,6 +316,15 @@ // must write a multiple of 4 bytes if ((uio->uio_resid & 0x3) != 0 || uio->uio_resid > MAX_BUF) return (EINVAL); + AT91_SSC_LOCK(sc); + err = 0; + // XXX non blocking I/O needs to bail here rather than wait. + while (err != EINTR && sc->flags & WRITE_BUSY) + err = msleep(&sc->txdone, &sc->sc_mtx, PCATCH | PZERO, + "sscwr2", 0); + if (err == EINTR) + return (EINTR); + sc->flags |= WRITE_BUSY; WR4(sc, SSC_CR, SSC_CR_TXDIS); WR4(sc, PDC_PTCR, PDC_PTCR_TXTDIS); txdone = sc->txdone; @@ -317,11 +332,13 @@ sc, 0); if (err != 0 && err != EINPROGRESS) return (err); - do { + err = 0; + while (txdone == sc->txdone && err != EINTR) err = msleep(&sc->txdone, &sc->sc_mtx, PCATCH | PZERO, - "sscwr", hz); - } while (txdone == sc->txdone && err != EINTR); + "sscwr", 0); bus_dmamap_sync(sc->tag, sc->tx_map, BUS_DMASYNC_POSTWRITE); + sc->flags &= ~WRITE_BUSY; + AT91_SSC_UNLOCK(sc); if (err == 0) uio->uio_resid = 0; return err;
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