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?
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);
}
}
