On Tue, May 22, 2018 at 05:43:01PM +0200, Mark Kettenis wrote:
> > Date: Mon, 21 May 2018 17:25:47 -0700
> > From: Mike Larkin <[email protected]>
> >
> > On Mon, May 21, 2018 at 12:44:47PM +0200, Mark Kettenis wrote:
> > > The diff below fixes I2C_OP_WRITE_WITH_STOP operations. Currently we
> > > run the read completion code for those operations, but since there is
> > > no data to read, this fails. Instead, this waits until a stop is
> > > detected. That doesn't seem to work for I2C_F_POLL operations though,
> > > so in that case we wait until the bus is idle. This also adds
> > > interlocks (using splbio/splx) on the existing tsleep() operations.
> > >
> > > This doesn't fix all the issues with the driver. In particular it
> > > seems that large reads still cause problems. I think a somewhat more
> > > invasive re-write of the dwiic_i2c_exec() function is needed. But I'd
> > > like to get this in before I embark on that.
> > >
> > > ok?
> > >
> >
> > The diff reads ok to me, do you want us to do any sort of testing here
> > before
> > commit?
>
> Testing is always appreciated, and a goood idea if you own a machine
> that relies on dwiic(4). For example those with machines that have a
> keyboard or touchpad/screen connected over i2c.
>
> Cheers,
>
> Mark
>
No regressions seen here.
-ml
> > > Index: dev/ic/dwiic.c
> > > ===================================================================
> > > RCS file: /cvs/src/sys/dev/ic/dwiic.c,v
> > > retrieving revision 1.3
> > > diff -u -p -r1.3 dwiic.c
> > > --- dev/ic/dwiic.c 19 Jan 2018 18:20:38 -0000 1.3
> > > +++ dev/ic/dwiic.c 21 May 2018 10:37:50 -0000
> > > @@ -192,6 +192,7 @@ dwiic_i2c_exec(void *cookie, i2c_op_t op
> > > u_int32_t ic_con, st, cmd, resp;
> > > int retries, tx_limit, rx_avail, x, readpos;
> > > uint8_t *b;
> > > + int s;
> > >
> > > if (sc->sc_busy)
> > > return 1;
> > > @@ -245,12 +246,14 @@ dwiic_i2c_exec(void *cookie, i2c_op_t op
> > > if (flags & I2C_F_POLL)
> > > DELAY(200);
> > > else {
> > > + s = splbio();
> > > dwiic_read(sc, DW_IC_CLR_INTR);
> > > dwiic_write(sc, DW_IC_INTR_MASK, DW_IC_INTR_TX_EMPTY);
> > >
> > > if (tsleep(&sc->sc_writewait, PRIBIO, "dwiic", hz / 2) != 0)
> > > printf("%s: timed out waiting for tx_empty intr\n",
> > > sc->sc_dev.dv_xname);
> > > + splx(s);
> > > }
> > >
> > > /* send our command, one byte at a time */
> > > @@ -320,7 +323,7 @@ dwiic_i2c_exec(void *cookie, i2c_op_t op
> > > * As TXFLR fills up, we need to clear it out by reading all
> > > * available data.
> > > */
> > > - while (tx_limit == 0 || x == len) {
> > > + while (I2C_OP_READ_P(op) && (tx_limit == 0 || x == len)) {
> > > DPRINTF(("%s: %s: tx_limit %d, sent %d read reqs\n",
> > > sc->sc_dev.dv_xname, __func__, tx_limit, x));
> > >
> > > @@ -332,6 +335,7 @@ dwiic_i2c_exec(void *cookie, i2c_op_t op
> > > DELAY(50);
> > > }
> > > } else {
> > > + s = splbio();
> > > dwiic_read(sc, DW_IC_CLR_INTR);
> > > dwiic_write(sc, DW_IC_INTR_MASK,
> > > DW_IC_INTR_RX_FULL);
> > > @@ -341,6 +345,7 @@ dwiic_i2c_exec(void *cookie, i2c_op_t op
> > > printf("%s: timed out waiting for "
> > > "rx_full intr\n",
> > > sc->sc_dev.dv_xname);
> > > + splx(s);
> > >
> > > rx_avail = dwiic_read(sc, DW_IC_RXFLR);
> > > }
> > > @@ -378,6 +383,32 @@ dwiic_i2c_exec(void *cookie, i2c_op_t op
> > > }
> > > }
> > >
> > > + if (I2C_OP_STOP_P(op) && I2C_OP_WRITE_P(op)) {
> > > + if (flags & I2C_F_POLL) {
> > > + /* wait for bus to be idle */
> > > + for (retries = 100; retries > 0; retries--) {
> > > + st = dwiic_read(sc, DW_IC_STATUS);
> > > + if (!(st & DW_IC_STATUS_ACTIVITY))
> > > + break;
> > > + DELAY(1000);
> > > + }
> > > + if (st & DW_IC_STATUS_ACTIVITY)
> > > + printf("%s: timed out waiting for bus idle\n",
> > > + sc->sc_dev.dv_xname);
> > > + } else {
> > > + s = splbio();
> > > + while (sc->sc_busy) {
> > > + dwiic_write(sc, DW_IC_INTR_MASK,
> > > + DW_IC_INTR_STOP_DET);
> > > + if (tsleep(&sc->sc_busy, PRIBIO, "dwiic",
> > > + hz / 2) != 0)
> > > + printf("%s: timed out waiting for "
> > > + "stop intr\n",
> > > + sc->sc_dev.dv_xname);
> > > + }
> > > + splx(s);
> > > + }
> > > + }
> > > sc->sc_busy = 0;
> > >
> > > return 0;
> > > @@ -449,6 +480,11 @@ dwiic_intr(void *arg)
> > > DPRINTF(("%s: %s: waking up writer\n",
> > > sc->sc_dev.dv_xname, __func__));
> > > wakeup(&sc->sc_writewait);
> > > + }
> > > + if (stat & DW_IC_INTR_STOP_DET) {
> > > + dwiic_write(sc, DW_IC_INTR_MASK, 0);
> > > + sc->sc_busy = 0;
> > > + wakeup(&sc->sc_busy);
> > > }
> > > }
> > >
> > >
> >
