Module Name: src
Committed By: riastradh
Date: Tue Jul 18 10:03:35 UTC 2023
Modified Files:
src/sys/dev/acpi: acpi_ec.c
Log Message:
acpiec(4): Clarify lock order and sprinkle lock assertions.
No functional change intended.
To generate a diff of this commit:
cvs rdiff -u -r1.88 -r1.89 src/sys/dev/acpi/acpi_ec.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/dev/acpi/acpi_ec.c
diff -u src/sys/dev/acpi/acpi_ec.c:1.88 src/sys/dev/acpi/acpi_ec.c:1.89
--- src/sys/dev/acpi/acpi_ec.c:1.88 Tue Jul 18 10:02:25 2023
+++ src/sys/dev/acpi/acpi_ec.c Tue Jul 18 10:03:35 2023
@@ -1,4 +1,4 @@
-/* $NetBSD: acpi_ec.c,v 1.88 2023/07/18 10:02:25 riastradh Exp $ */
+/* $NetBSD: acpi_ec.c,v 1.89 2023/07/18 10:03:35 riastradh Exp $ */
/*-
* Copyright (c) 2007 Joerg Sonnenberger <jo...@netbsd.org>.
@@ -34,14 +34,12 @@
* - read and write access from ASL, e.g. to read battery state
* - notification of ASL of System Control Interrupts.
*
- * Access to the EC is serialised by sc_access_mtx and optionally the
- * ACPI global mutex. Both locks are held until the request is fulfilled.
- * All access to the softc has to hold sc_mtx to serialise against the GPE
- * handler and the callout. sc_mtx is also used for wakeup conditions.
+ * Lock order:
+ * sc_access_mtx (serializes EC transactions -- read, write, or SCI)
+ * -> ACPI global lock (excludes other ACPI access during EC transaction)
+ * -> sc_mtx (serializes state machine transitions and waits)
*
- * SCIs are processed in a kernel thread. Handling gets a bit complicated
- * by the lock order (sc_mtx must be acquired after sc_access_mtx and the
- * ACPI global mutex).
+ * SCIs are processed in a kernel thread.
*
* Read and write requests spin around for a short time as many requests
* can be handled instantly by the EC. During normal processing interrupt
@@ -59,7 +57,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: acpi_ec.c,v 1.88 2023/07/18 10:02:25 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: acpi_ec.c,v 1.89 2023/07/18 10:03:35 riastradh Exp $");
#ifdef _KERNEL_OPT
#include "opt_acpi_ec.h"
@@ -566,6 +564,8 @@ acpiec_read_data(struct acpiec_softc *sc
{
uint8_t x;
+ KASSERT(mutex_owned(&sc->sc_mtx));
+
x = bus_space_read_1(sc->sc_data_st, sc->sc_data_sh, 0);
DPRINTF(ACPIEC_DEBUG_REG, sc, "read data=0x%"PRIx8"\n", x);
@@ -576,6 +576,8 @@ static void
acpiec_write_data(struct acpiec_softc *sc, uint8_t val)
{
+ KASSERT(mutex_owned(&sc->sc_mtx));
+
DPRINTF(ACPIEC_DEBUG_REG, sc, "write data=0x%"PRIx8"\n", val);
bus_space_write_1(sc->sc_data_st, sc->sc_data_sh, 0, val);
}
@@ -585,6 +587,8 @@ acpiec_read_status(struct acpiec_softc *
{
uint8_t x;
+ KASSERT(mutex_owned(&sc->sc_mtx));
+
x = bus_space_read_1(sc->sc_csr_st, sc->sc_csr_sh, 0);
DPRINTF(ACPIEC_DEBUG_REG, sc, "read status=0x%"PRIx8"\n", x);
@@ -595,6 +599,8 @@ static void
acpiec_write_command(struct acpiec_softc *sc, uint8_t cmd)
{
+ KASSERT(mutex_owned(&sc->sc_mtx));
+
DPRINTF(ACPIEC_DEBUG_REG, sc, "write command=0x%"PRIx8"\n", cmd);
bus_space_write_1(sc->sc_csr_st, sc->sc_csr_sh, 0, cmd);
}
@@ -918,6 +924,8 @@ acpiec_gpe_state_machine(device_t dv)
struct acpiec_softc *sc = device_private(dv);
uint8_t reg;
+ KASSERT(mutex_owned(&sc->sc_mtx));
+
reg = acpiec_read_status(sc);
#ifdef ACPIEC_DEBUG
