acpi_spmc(4): Enable multiple instances

Support the (so far hypothetical) case of a machine with multiple
instances of the PNP0D80 device (e.g., if multiple DSMs are not
implemented on the same device), by allowing multiple instances of the
device to co-exist.

This is achieved by moving 'supported_functions' from 'struct dsm' into
the softc, so each instance has its own view of which functions are
supported.

Consequently, the check on the instance unit on probe can be removed.

Reviewed by:    imp (older version), obiwac
Sponsored by:   The FreeBSD Foundation
Differential Revision:  https://reviews.freebsd.org/D56817

sys/dev/acpica/acpi_spmc.c

@@ -74,7 +74,6 @@ struct dsm_desc {
 	 */
 	int			 revision;
 	struct uuid		 uuid;
-	uint64_t		 supported_functions;
 	uint64_t		 expected_functions;
 	uint64_t		 extra_functions;
 	/* Human-friendly names of known functions. */
@@ -129,7 +128,7 @@ static const char *const dsm_ms_function_names[] = {
 	[DSM_MS_TURN_ON_DISPLAY] = "TURN_ON",
 };
 
-static struct dsm_desc dsm_ms = {
+static const struct dsm_desc dsm_ms = {
 	.index = DSM_MS,
 	.name = "Microsoft",
 	.uuid = { /* 11e00d56-ce64-47ce-837b-1f898f9aa461 */
@@ -185,7 +184,7 @@ static struct dsm_desc dsm_amd = {
 	.function_names_nb = nitems(dsm_amd_function_names),
 };
 
-static struct dsm_desc *const dsms[] = {
+static const struct dsm_desc *const dsms[] = {
 	[DSM_INTEL] = &dsm_intel,
 	[DSM_MS] = &dsm_ms,
 	[DSM_AMD] = &dsm_amd,
@@ -219,6 +218,7 @@ struct acpi_spmc_softc {
 	device_t		dev;
 	ACPI_HANDLE		handle;
 	int			dsms;
+	uint64_t		supported_functions[nitems(dsms)];
 
 	struct eventhandler_entry	*eh_suspend;
 	struct eventhandler_entry	*eh_resume;
@@ -239,9 +239,13 @@ resolve_dsm(int dsm_index)
 }
 
 static bool
-supports_function(const struct dsm_desc *const dsm, const int function_index)
+supports_function(const struct acpi_spmc_softc *const sc, const int dsm_index,
+    const int function_index)
 {
-	return ((dsm->supported_functions & IDX_TO_BIT(function_index)) != 0);
+	MPASS(0 <= dsm_index && dsm_index < nitems(sc->supported_functions));
+
+	return ((sc->supported_functions[dsm_index] &
+	    IDX_TO_BIT(function_index)) != 0);
 }
 
 static bool
@@ -329,7 +333,7 @@ failed_to_call_dsm(const struct acpi_spmc_softc *const sc,
 }
 
 static void	acpi_spmc_probe_dsm(struct acpi_spmc_softc *sc,
-		    ACPI_HANDLE handle, struct dsm_desc *const dsm);
+		    ACPI_HANDLE handle, const struct dsm_desc *const dsm);
 static void	acpi_spmc_dsm_print_functions(
 		    const struct acpi_spmc_softc *const sc,
 		    const struct dsm_desc *const dsm);
@@ -351,11 +355,6 @@ acpi_spmc_probe(device_t dev)
 	if (ACPI_ID_PROBE(device_get_parent(dev), dev, spmc_ids, &name) > 0)
 		return (ENXIO);
 
-	if (device_get_unit(dev) > 0) {
-		device_printf(dev, "shouldn't have more than one SPMC");
-		return (ENXIO);
-	}
-
 	device_set_desc(dev, "System Power Management Controller");
 
 	return (BUS_PROBE_DEFAULT);
@@ -431,16 +430,17 @@ static void
 acpi_spmc_dsm_print_functions(const struct acpi_spmc_softc *const sc,
     const struct dsm_desc *const dsm)
 {
-	const uint64_t missing = dsm->expected_functions &
+	const uint64_t supported_functions =
-	    ~dsm->supported_functions;
+	    sc->supported_functions[dsm->index];
-	const uint64_t unknown = dsm->supported_functions &
+	const uint64_t missing = dsm->expected_functions & ~supported_functions;
+	const uint64_t unknown = supported_functions &
 	    ~(dsm->expected_functions | dsm->extra_functions);
 	char buf[128];
 
-	print_bit_field(buf, sizeof(buf), dsm->supported_functions,
+	print_bit_field(buf, sizeof(buf), supported_functions,
 	    "FUNC", pbf_function_name, dsm);
 	device_printf(sc->dev, "DSM %s: Supported functions: %#" PRIx64 "%s\n",
-	    dsm->name, dsm->supported_functions, buf);
+	    dsm->name, supported_functions, buf);
 
 	if (missing != 0) {
 		print_bit_field(buf, sizeof(buf), missing, "FUNC",
@@ -461,17 +461,17 @@ acpi_spmc_dsm_print_functions(const struct acpi_spmc_softc *const sc,
 
 static void
 acpi_spmc_probe_dsm(struct acpi_spmc_softc *sc, ACPI_HANDLE handle,
-    struct dsm_desc *const dsm)
+    const struct dsm_desc *const dsm)
 {
 	const uint64_t supported_functions = acpi_DSMQuery(handle,
-	    (uint8_t *)&dsm->uuid, dsm->revision);
+	    (const uint8_t *)&dsm->uuid, dsm->revision);
 
 	/*
 	 * DSM is supported if bit 0 is set.
 	 */
 	if ((supported_functions & 1) == 0)
 		return;
-	dsm->supported_functions = supported_functions & ~1;
+	sc->supported_functions[dsm->index] = supported_functions & ~1;
 	sc->dsms |= IDX_TO_BIT(dsm->index);
 }
 
@@ -798,7 +798,7 @@ acpi_spmc_exit_notif(device_t dev)
 		acpi_spmc_run_dsm(dev, &dsm_amd, DSM_AMD_LPI_EXIT_NOTIF);
 	if (has_dsm(sc, DSM_MS)) {
 		acpi_spmc_run_dsm(dev, &dsm_ms, DSM_INTEL_MS_LPI_EXIT_NOTIF);
-		if (supports_function(&dsm_ms, DSM_MS_TURN_ON_DISPLAY))
+		if (supports_function(sc, DSM_MS, DSM_MS_TURN_ON_DISPLAY))
 			acpi_spmc_run_dsm(dev, &dsm_ms,
 			    DSM_MS_TURN_ON_DISPLAY);
 		acpi_spmc_run_dsm(dev, &dsm_ms, DSM_MS_SLEEP_EXIT_NOTIF);