From 5857fba5fd56148d42e3098fc8c469144a8d5961 Mon Sep 17 00:00:00 2001
From: Ben Widawsky <bwidawsk@FreeBSD.org>
Date: Wed, 11 Jul 2018 01:37:01 +0000
Subject: [PATCH] acpidump(8): Add ACPI LPIT (Low Power Idle Table)

The LPIT is the part of the "standardized" way that one can enumerate
various power state information on Intel platforms.

The documentation for this change can be found here:
http://www.uefi.org/sites/default/files/resources/Intel_ACPI_Low_Power_S0_Idle.pdf

Reviewed By: jhb
Approved By: jhb
Differential Revision: https://reviews.freebsd.org/D15931
---
 usr.sbin/acpi/acpidump/acpi.c     | 76 +++++++++++++++++++++++++++++++
 usr.sbin/acpi/acpidump/acpidump.8 |  3 +-
 2 files changed, 78 insertions(+), 1 deletion(-)

diff --git a/usr.sbin/acpi/acpidump/acpi.c b/usr.sbin/acpi/acpidump/acpi.c
index 867b2fb169d4..377e0fee315d 100644
--- a/usr.sbin/acpi/acpidump/acpi.c
+++ b/usr.sbin/acpi/acpidump/acpi.c
@@ -68,6 +68,7 @@ static void	acpi_handle_hpet(ACPI_TABLE_HEADER *sdp);
 static void	acpi_handle_mcfg(ACPI_TABLE_HEADER *sdp);
 static void	acpi_handle_slit(ACPI_TABLE_HEADER *sdp);
 static void	acpi_handle_wddt(ACPI_TABLE_HEADER *sdp);
+static void	acpi_handle_lpit(ACPI_TABLE_HEADER *sdp);
 static void	acpi_print_srat_cpu(uint32_t apic_id, uint32_t proximity_domain,
 		    uint32_t flags);
 static void	acpi_print_srat_memory(ACPI_SRAT_MEM_AFFINITY *mp);
@@ -715,6 +716,79 @@ acpi_handle_wddt(ACPI_TABLE_HEADER *sdp)
 	printf(END_COMMENT);
 }
 
+static void
+acpi_print_native_lpit(ACPI_LPIT_NATIVE *nl)
+{
+	printf("\tEntryTrigger=");
+	acpi_print_gas(&nl->EntryTrigger);
+	printf("\tResidency=%u\n", nl->Residency);
+	printf("\tLatency=%u\n", nl->Latency);
+	if (nl->Header.Flags & ACPI_LPIT_NO_COUNTER)
+		printf("\tResidencyCounter=Not Present");
+	else {
+		printf("\tResidencyCounter=");
+		acpi_print_gas(&nl->ResidencyCounter);
+	}
+	if (nl->CounterFrequency)
+		printf("\tCounterFrequency=%ju\n", nl->CounterFrequency);
+	else
+		printf("\tCounterFrequency=TSC\n");
+}
+
+static void
+acpi_print_lpit(ACPI_LPIT_HEADER *lpit)
+{
+	if (lpit->Type == ACPI_LPIT_TYPE_NATIVE_CSTATE)
+		printf("\tType=ACPI_LPIT_TYPE_NATIVE_CSTATE\n");
+	else
+		warnx("unknown LPIT type %u", lpit->Type);
+
+	printf("\tLength=%u\n", lpit->Length);
+	printf("\tUniqueId=0x%04x\n", lpit->UniqueId);
+#define	PRINTFLAG(var, flag)	printflag((var), ACPI_LPIT_## flag, #flag)
+	printf("\tFlags=");
+	PRINTFLAG(lpit->Flags, STATE_DISABLED);
+	PRINTFLAG_END();
+#undef PRINTFLAG
+
+	if (lpit->Type == ACPI_LPIT_TYPE_NATIVE_CSTATE)
+		return acpi_print_native_lpit((ACPI_LPIT_NATIVE *)lpit);
+}
+
+static void
+acpi_walk_lpit(ACPI_TABLE_HEADER *table, void *first,
+    void (*action)(ACPI_LPIT_HEADER *))
+{
+	ACPI_LPIT_HEADER *subtable;
+	char *end;
+
+	subtable = first;
+	end = (char *)table + table->Length;
+	while ((char *)subtable < end) {
+		printf("\n");
+		if (subtable->Length < sizeof(ACPI_LPIT_HEADER)) {
+			warnx("invalid subtable length %u", subtable->Length);
+			return;
+		}
+		action(subtable);
+		subtable = (ACPI_LPIT_HEADER *)((char *)subtable +
+		    subtable->Length);
+	}
+}
+
+static void
+acpi_handle_lpit(ACPI_TABLE_HEADER *sdp)
+{
+	ACPI_TABLE_LPIT *lpit;
+
+	printf(BEGIN_COMMENT);
+	acpi_print_sdt(sdp);
+	lpit = (ACPI_TABLE_LPIT *)sdp;
+	acpi_walk_lpit(sdp, (lpit + 1), acpi_print_lpit);
+
+	printf(END_COMMENT);
+}
+
 static void
 acpi_print_srat_cpu(uint32_t apic_id, uint32_t proximity_domain,
     uint32_t flags)
@@ -1693,6 +1767,8 @@ acpi_handle_rsdt(ACPI_TABLE_HEADER *rsdp)
 			acpi_handle_nfit(sdp);
 		else if (!memcmp(sdp->Signature, ACPI_SIG_WDDT, 4))
 			acpi_handle_wddt(sdp);
+		else if (!memcmp(sdp->Signature, ACPI_SIG_LPIT, 4))
+			acpi_handle_lpit(sdp);
 		else {
 			printf(BEGIN_COMMENT);
 			acpi_print_sdt(sdp);
diff --git a/usr.sbin/acpi/acpidump/acpidump.8 b/usr.sbin/acpi/acpidump/acpidump.8
index 834c5c99c591..d98fd38d44fb 100644
--- a/usr.sbin/acpi/acpidump/acpidump.8
+++ b/usr.sbin/acpi/acpidump/acpidump.8
@@ -29,7 +29,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd June 20, 2018
+.Dd July 10, 2018
 .Dt ACPIDUMP 8
 .Os
 .Sh NAME
@@ -103,6 +103,7 @@ utility dumps contents of the following tables:
 .It FACS
 .It FADT
 .It HPET
+.It LPIT
 .It MADT
 .It MCFG
 .It NFIT