From 7b29897efb400030c4e21777281d9fe673194ac7 Mon Sep 17 00:00:00 2001
From: Rafal Kupiec <belliash@codingworkshop.eu.org>
Date: Tue, 4 Jun 2024 21:04:09 +0200
Subject: [PATCH] Initialize ACPI Timer

---
 sdk/xtdk/hltypes.h          | 16 +++++++++++++-
 xtoskrnl/hl/acpi.c          | 44 +++++++++++++++++++++++++++++++++++++
 xtoskrnl/hl/globals.c       |  3 +++
 xtoskrnl/includes/globals.h |  3 +++
 xtoskrnl/includes/hli.h     |  4 ++++
 5 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/sdk/xtdk/hltypes.h b/sdk/xtdk/hltypes.h
index da6fa9e..fcee4e7 100644
--- a/sdk/xtdk/hltypes.h
+++ b/sdk/xtdk/hltypes.h
@@ -59,6 +59,13 @@
 #define ACPI_WSMT_SIGNATURE         0x544D5357 /* Windows SMM Security Mitigation Table */
 #define ACPI_XSDT_SIGNATURE         0x54445358 /* eXtended System Descriptor Table */
 
+/* ACPI FADT flags masks */
+#define ACPI_FADT_32BIT_TIMER       (1<<8)
+
+/* ACPI Timer bit masks */
+#define ACPI_FADT_TIMER_32BIT       0x80000000
+#define ACPI_FADT_TIMER_24BIT       0x00800000
+
 /* Default serial port settings */
 #define COMPORT_CLOCK_RATE          0x1C200
 #define COMPORT_WAIT_TIMEOUT        204800
@@ -205,7 +212,7 @@ typedef struct _ACPI_DESCRIPTION_HEADER
     ULONG CreatorRev;
 } ACPI_DESCRIPTION_HEADER, *PACPI_DESCRIPTION_HEADER;
 
-/* ACPI cache list */
+/* ACPI cache list structure */
 typedef struct _ACPI_CACHE_LIST
 {
     LIST_ENTRY ListEntry;
@@ -300,6 +307,13 @@ typedef struct _ACPI_FADT
     GENERIC_ADDRESS SleepStatusReg;
 } ACPI_FADT, *PACPI_FADT;
 
+/* ACPI Timer information structure */
+typedef struct _ACPI_TIMER_INFO
+{
+    ULONG TimerPort;
+    ULONG MsbMask;
+} ACPI_TIMER_INFO, *PACPI_TIMER_INFO;
+
 /* Serial (COM) port initial state */
 typedef struct _CPPORT
 {
diff --git a/xtoskrnl/hl/acpi.c b/xtoskrnl/hl/acpi.c
index 0ccd0c7..028eca4 100644
--- a/xtoskrnl/hl/acpi.c
+++ b/xtoskrnl/hl/acpi.c
@@ -121,6 +121,9 @@ HlpInitializeAcpi(VOID)
         return STATUS_NOT_FOUND;
     }
 
+    /* Initialize ACPI timer */
+    HlpInitializeAcpiTimer();
+
     /* Return success */
     return STATUS_SUCCESS;
 }
@@ -251,6 +254,47 @@ HlpInitializeAcpiSystemDescriptionTable(OUT PACPI_DESCRIPTION_HEADER *AcpiTable)
     return STATUS_SUCCESS;
 }
 
+/**
+ * Initializes the ACPI Timer.
+ *
+ * @return This routine returns a status code.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+XTSTATUS
+HlpInitializeAcpiTimer(VOID)
+{
+    PACPI_FADT Fadt;
+    XTSTATUS Status;
+
+    /* Get Fixed ACPI Description Table (FADT) */
+    Status = HlGetAcpiTable(ACPI_FADT_SIGNATURE, (PACPI_DESCRIPTION_HEADER*)&Fadt);
+    if(Status != STATUS_SUCCESS || !Fadt)
+    {
+        /* Failed to get FADT, return error */
+        return STATUS_NOT_FOUND;
+    }
+
+    /* Set ACPI timer port address */
+    HlpAcpiTimerInfo.TimerPort = Fadt->PmTmrBlkIoPort;
+
+    /* Determine whether 32-bit or 24-bit timer is used */
+    if(Fadt->Flags & ACPI_FADT_32BIT_TIMER)
+    {
+        /* 32-bit timer */
+        HlpAcpiTimerInfo.MsbMask = ACPI_FADT_TIMER_32BIT;
+    }
+    else
+    {
+        /* 24-bit timer */
+        HlpAcpiTimerInfo.MsbMask = ACPI_FADT_TIMER_24BIT;
+    }
+
+    /* Return success */
+    return STATUS_SUCCESS;
+}
+
 /**
  * Queries kernel local ACPI cache in attempt to find a requested ACPI table.
  *
diff --git a/xtoskrnl/hl/globals.c b/xtoskrnl/hl/globals.c
index 080df03..e7e45e8 100644
--- a/xtoskrnl/hl/globals.c
+++ b/xtoskrnl/hl/globals.c
@@ -15,6 +15,9 @@ LIST_ENTRY HlpAcpiCacheList;
 /* ACPI Root System Description Pointer (RSDP) */
 PACPI_RSDP HlpAcpiRsdp;
 
+/* ACPI timer information */
+ACPI_TIMER_INFO HlpAcpiTimerInfo;
+
 /* Active processors count */
 KAFFINITY HlpActiveProcessors;
 
diff --git a/xtoskrnl/includes/globals.h b/xtoskrnl/includes/globals.h
index 4b11faf..90b9dce 100644
--- a/xtoskrnl/includes/globals.h
+++ b/xtoskrnl/includes/globals.h
@@ -18,6 +18,9 @@ EXTERN LIST_ENTRY HlpAcpiCacheList;
 /* ACPI Root System Description Pointer (RSDP) */
 EXTERN PACPI_RSDP HlpAcpiRsdp;
 
+/* ACPI timer information */
+EXTERN ACPI_TIMER_INFO HlpAcpiTimerInfo;
+
 /* Active processors count */
 EXTERN KAFFINITY HlpActiveProcessors;
 
diff --git a/xtoskrnl/includes/hli.h b/xtoskrnl/includes/hli.h
index def5551..1ceecfc 100644
--- a/xtoskrnl/includes/hli.h
+++ b/xtoskrnl/includes/hli.h
@@ -95,6 +95,10 @@ XTAPI
 XTSTATUS
 HlpInitializeAcpiSystemDescriptionTable(OUT PACPI_DESCRIPTION_HEADER *AcpiTable);
 
+XTAPI
+XTSTATUS
+HlpInitializeAcpiTimer(VOID);
+
 XTAPI
 XTSTATUS
 HlpQueryAcpiCache(IN ULONG Signature,