svn commit: r356166 - head/sys/riscv/sifive
Philip Paeps
philip at FreeBSD.org
Sun Dec 29 04:26:10 UTC 2019
Author: philip
Date: Sun Dec 29 04:26:10 2019
New Revision: 356166
URL: https://svnweb.freebsd.org/changeset/base/356166
Log:
fuspi: Fix 'sleepable after non-sleepable' lock
With WITNESS enabled we see the following warning:
lock order reversal: (sleepable after non-sleepable)
1st 0xffffffd0847c7210 fu540spi0 (fu540spi0) @
/usr/home/kp/axiado/hornet-freebsd/src/sys/riscv/sifive/fu540_spi.c:297
2nd 0xffffffc00372bb30 Clock topology lock (Clock topology lock) @
/usr/home/kp/axiado/hornet-freebsd/src/sys/dev/extres/clk/clk.c:1137
stack backtrace:
#0 0xffffffc0002a579e at witness_checkorder+0xb72
#1 0xffffffc0002a5556 at witness_checkorder+0x92a
#2 0xffffffc000254c7a at _sx_slock_int+0x66
#3 0xffffffc00025537a at _sx_slock+0x8
#4 0xffffffc000123022 at clk_get_freq+0x38
#5 0xffffffc0005463e4 at __clzdi2+0x2bb8
#6 0xffffffc00014af58 at randomdev_getkey+0x76e
#7 0xffffffc0001278b0 at simplebus_add_device+0x7ee
#8 0xffffffc00027c9a8 at device_attach+0x2e6
#9 0xffffffc00027c634 at device_probe_and_attach+0x7a
#10 0xffffffc00027d76a at bus_generic_attach+0x10
#11 0xffffffc00014aab0 at randomdev_getkey+0x2c6
#12 0xffffffc00027c9a8 at device_attach+0x2e6
#13 0xffffffc00027c634 at device_probe_and_attach+0x7a
#14 0xffffffc00027d76a at bus_generic_attach+0x10
#15 0xffffffc000278bd2 at config_intrhook_oneshot+0x52
#16 0xffffffc000278b3e at config_intrhook_establish+0x146
#17 0xffffffc000278cf2 at config_intrhook_disestablish+0xfe
The clock topology lock can sleep, which means we cannot attempt to
acquire it while holding the non-sleepable mutex.
Fix that by retrieving the clock speed once, during attach and not every
time during SPI transaction setup.
Submitted by: kp
Sponsored by: Axiado
Modified:
head/sys/riscv/sifive/fu540_spi.c
Modified: head/sys/riscv/sifive/fu540_spi.c
==============================================================================
--- head/sys/riscv/sifive/fu540_spi.c Sun Dec 29 02:12:18 2019 (r356165)
+++ head/sys/riscv/sifive/fu540_spi.c Sun Dec 29 04:26:10 2019 (r356166)
@@ -80,6 +80,7 @@ struct fuspi_softc {
void *ih;
clk_t clk;
+ uint64_t freq;
uint32_t cs_max;
};
@@ -207,22 +208,14 @@ fuspi_setup(struct fuspi_softc *sc, uint32_t cs, uint3
uint32_t freq)
{
uint32_t csmode, fmt, sckdiv, sckmode;
- uint64_t clock;
- int ret;
FUSPI_ASSERT_LOCKED(sc);
- ret = clk_get_freq(sc->clk, &clock);
- if (ret) {
- device_printf(sc->dev, "Cannot get clock frequency: %d\n", ret);
- return (ret);
- }
-
/*
* Fsck = Fin / 2 * (div + 1)
* -> div = Fin / (2 * Fsck) - 1
*/
- sckdiv = (howmany(clock >> 1, freq) - 1) & FUSPI_SCKDIV_MASK;
+ sckdiv = (howmany(sc->freq >> 1, freq) - 1) & FUSPI_SCKDIV_MASK;
FUSPI_WRITE(sc, FUSPI_REG_SCKDIV, sckdiv);
switch (mode) {
@@ -328,6 +321,12 @@ fuspi_attach(device_t dev)
error = clk_enable(sc->clk);
if (error) {
device_printf(dev, "Couldn't enable clock: %d\n", error);
+ goto fail;
+ }
+
+ error = clk_get_freq(sc->clk, &sc->freq);
+ if (error) {
+ device_printf(sc->dev, "Couldn't get frequency: %d\n", error);
goto fail;
}
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