git: 69cfa60ddd4d - main - twsi: protect interaction between twsi_transfer and twsi_intr
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Date: Fri, 26 Nov 2021 14:23:57 UTC
The branch main has been updated by avg: URL: https://cgit.FreeBSD.org/src/commit/?id=69cfa60ddd4df814b507699f9bb7253ece054f40 commit 69cfa60ddd4df814b507699f9bb7253ece054f40 Author: Andriy Gapon <avg@FreeBSD.org> AuthorDate: 2021-11-26 07:25:01 +0000 Commit: Andriy Gapon <avg@FreeBSD.org> CommitDate: 2021-11-26 14:14:28 +0000 twsi: protect interaction between twsi_transfer and twsi_intr All accesses to softc are now done under a mutex to prevent data races between the open context and the interrupt handler. Additionally, the wait time in twsi_transfer is bounded now. Previously we could get stuck there forever if an interrupt got lost. MFC after: 2 weeks --- sys/dev/iicbus/twsi/twsi.c | 36 +++++++++++++++++++++++++++--------- 1 file changed, 27 insertions(+), 9 deletions(-) diff --git a/sys/dev/iicbus/twsi/twsi.c b/sys/dev/iicbus/twsi/twsi.c index 49fe608473b2..552787874833 100644 --- a/sys/dev/iicbus/twsi/twsi.c +++ b/sys/dev/iicbus/twsi/twsi.c @@ -484,13 +484,16 @@ static int twsi_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs) { struct twsi_softc *sc; + int error; sc = device_get_softc(dev); if (!sc->have_intr) return (iicbus_transfer_gen(dev, msgs, nmsgs)); - sc->error = 0; + mtx_lock(&sc->mutex); + KASSERT(sc->transfer == 0, + ("starting a transfer while another is active")); sc->control_val = TWSI_CONTROL_TWSIEN | TWSI_CONTROL_INTEN | TWSI_CONTROL_ACK; @@ -501,6 +504,7 @@ twsi_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs) sc->msgs = msgs; sc->msg_idx = 0; sc->transfer = 1; + sc->error = 0; #ifdef TWSI_DEBUG for (int i = 0; i < nmsgs; i++) @@ -512,22 +516,25 @@ twsi_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs) if (sc->msgs[0].len == 1) sc->control_val &= ~TWSI_CONTROL_ACK; TWSI_WRITE(sc, sc->reg_control, sc->control_val | TWSI_CONTROL_START); - while (sc->error == 0 && sc->transfer != 0) { - tsleep_sbt(sc, 0, "twsi", SBT_1MS * 30, SBT_1MS, 0); - } + msleep_sbt(sc, &sc->mutex, 0, "twsi", 3000 * SBT_1MS, SBT_1MS, 0); debugf(sc, "pause finish\n"); - - if (sc->error) { - debugf(sc, "Error, aborting (%d)\n", sc->error); - TWSI_WRITE(sc, sc->reg_control, 0); + if (sc->error == 0 && sc->transfer != 0) { + device_printf(sc->dev, "transfer timeout\n"); + sc->error = IIC_ETIMEOUT; + sc->transfer = 0; } + if (sc->error != 0) + debugf(sc, "Error: %d\n", sc->error); + /* Disable module and interrupts */ debugf(sc, "status=%x\n", TWSI_READ(sc, sc->reg_status)); TWSI_WRITE(sc, sc->reg_control, 0); debugf(sc, "status=%x\n", TWSI_READ(sc, sc->reg_status)); + error = sc->error; + mtx_unlock(&sc->mutex); - return (sc->error); + return (error); } static void @@ -539,11 +546,20 @@ twsi_intr(void *arg) sc = arg; + mtx_lock(&sc->mutex); debugf(sc, "Got interrupt Current msg=%x\n", sc->msg_idx); status = TWSI_READ(sc, sc->reg_status); debugf(sc, "reg control=%x\n", TWSI_READ(sc, sc->reg_control)); + if (sc->transfer == 0) { + device_printf(sc->dev, "interrupt without active transfer, " + "status = 0x%x\n", status); + TWSI_WRITE(sc, sc->reg_control, sc->control_val | + TWSI_CONTROL_STOP); + goto end; + } + switch (status) { case TWSI_STATUS_START: case TWSI_STATUS_RPTD_START: @@ -670,6 +686,7 @@ twsi_intr(void *arg) } debugf(sc, "Refresh reg_control\n"); +end: /* * Newer Allwinner chips clear IFLG after writing 1 to it. */ @@ -681,6 +698,7 @@ twsi_intr(void *arg) sc->transfer = 0; wakeup(sc); } + mtx_unlock(&sc->mutex); } static void