ptos: drivers: Add ACPI driver groundwork

Signed-off-by: Chloe M <chloe@mensia.org>

service/ptos/drivers/acpi/acpi.c

@@ -0,0 +1,111 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ *
+ * Description: ACPI init
+ * Author:      Chloe M.
+ */
+
+#include <drivers/acpi/acpi.h>
+#include <drivers/acpi/tables.h>
+#include <ex/trace.h>
+#include <mm/vm.h>
+#include <ke/bpal.h>
+#include <ke/bugcheck.h>
+#include <string.h>
+
+#define DTRACE(Fmt, ...) \
+    TRACE("[ ACPI ]: " Fmt, ##__VA_ARGS__)
+
+static ACPI_RSDP *Rsdp;
+static ACPI_ROOT_SDT *RootSdt;
+static USIZE RootSdtEntries;
+
+static VOID
+AcpiPrintVendor(VOID)
+{
+    UCHAR Revision;
+
+    /*
+     * On certain emulators this may become zero, just bump it up to
+     * one because its behaviors are the same.
+     */
+    Revision = Rsdp->Revision;
+    if (Revision == 0) {
+        ++Revision;
+    }
+
+    DTRACE("detected acpi %d.0 by %.6s\n", Revision, Rsdp->Oemid);
+}
+
+static VOID
+RsdpVerify(VOID)
+{
+    UCHAR Checksum = 0;
+    USIZE Idx;
+
+    for (Idx = 0; Idx < Rsdp->Length; ++Idx) {
+        Checksum += ((UCHAR *)Rsdp)[Idx];
+    }
+
+    if ((Checksum & 0xFF) != 0) {
+        KeBugCheck(
+            BUGCHECK_BAD_CHECKSUM,
+            "Got bad checksum %x for ACPI RSDP\n",
+            Checksum
+        );
+    }
+
+    DTRACE("checksum ok\n");
+}
+
+VOID *
+AcpiQuery(const CHAR *Signature)
+{
+    BOOLEAN IsMatch;
+    ACPI_HEADER *Header;
+    UPTR Pma;
+    USIZE Idx;
+
+    if (Signature == NULL) {
+        return NULL;
+    }
+
+    for (Idx = 0; Idx < RootSdtEntries; ++Idx) {
+        Pma = (UPTR)RootSdt->Tables[Idx];
+        Header = (ACPI_HEADER *)PMA_TO_VMA(Pma);
+        IsMatch = !RtlMemCmp(
+            Header->Signature,
+            Signature,
+            sizeof(Header->Signature)
+        );
+
+        if (IsMatch) {
+            return (VOID *)Header;
+        }
+    }
+
+    return NULL;
+}
+
+VOID
+AcpiInit(VOID)
+{
+    BPAL_HANDLE BpalHandle;
+
+    KeBpalGetHandle(&BpalHandle);
+    Rsdp = BpalHandle.RsdpBase;
+    AcpiPrintVendor();
+    RsdpVerify();
+
+    /* Select the correct root sdt */
+    if (Rsdp->Revision < 2) {
+        DTRACE("using rsdt as root sdt\n");
+        RootSdt = PMA_TO_VMA((UPTR)Rsdp->RsdtAddr);
+        RootSdtEntries = (RootSdt->Header.Length - sizeof(RootSdt->Header)) / 4;
+    } else {
+        DTRACE("using xsdt as root sdt\n");
+        RootSdt = PMA_TO_VMA((UPTR)Rsdp->XsdtAddr);
+        RootSdtEntries = (RootSdt->Header.Length - sizeof(RootSdt->Header)) / 8;
+    }
+}

service/ptos/head/drivers/acpi/acpi.h

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ *
+ * Description: ACPI driver
+ * Author:      Chloe M.
+ */
+
+#ifndef _ACPI_ACPI_H_
+#define _ACPI_ACPI_H_ 1
+
+#include <ptdef.h>
+
+/*
+ * Initialize ACPI
+ */
+VOID AcpiInit(VOID);
+
+/*
+ * Query an ACPI structure
+ *
+ * @Signature: Signature to query for
+ *
+ * Returns the virtual structure base on success, otherwise
+ * NULL on failure.
+ */
+VOID *AcpiQuery(const CHAR *Signature);
+
+#endif  /* !_ACPI_ACPI_H_ */

service/ptos/head/drivers/acpi/tables.h

@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ *
+ * Description: ACPI definitions
+ * Author:      Chloe M.
+ */
+
+#ifndef _ACPI_TABLES_H_
+#define _ACPI_TABLES_H_ 1
+
+#include <ptdef.h>
+
+/* MADT APIC header types */
+#define APIC_TYPE_LOCAL_APIC            0
+#define APIC_TYPE_IO_APIC               1
+#define APIC_TYPE_INTERRUPT_OVERRIDE    2
+
+#define OEMID_SIZE 6
+
+typedef struct PACKED {
+    CHAR Signature[4];
+    ULONG Length;
+    UCHAR Revision;
+    UCHAR Checksum;
+    CHAR Oemid[OEMID_SIZE];
+    CHAR OemTableId[8];
+    ULONG OemRevision;
+    ULONG CreatorId;
+    ULONG CreatorRevision;
+} ACPI_HEADER;
+
+typedef struct PACKED {
+    UQUAD Signature;
+    UCHAR Checksum;
+    CHAR Oemid[OEMID_SIZE];
+    UCHAR Revision;
+    ULONG RsdtAddr;
+
+    /* Reserved if revision < 2 */
+    ULONG Length;
+    UQUAD XsdtAddr;
+    UCHAR ExtChecksum;
+    UCHAR Reserved[3];
+} ACPI_RSDP;
+
+/*
+ * XSDT or RSDT depending on the revision within the
+ * header
+ */
+typedef struct PACKED {
+    ACPI_HEADER Header;
+    ULONG Tables[];
+} ACPI_ROOT_SDT;
+
+typedef struct PACKED {
+    ACPI_HEADER Header;
+    ULONG LapicAddr;
+    ULONG Flags;
+} ACPI_MADT;
+
+typedef struct PACKED {
+    UCHAR Type;
+    UCHAR Length;
+} ACPI_APIC_HEADER;
+
+typedef struct PACKED {
+    ACPI_APIC_HEADER Header;
+    UCHAR ProcessorId;
+    UCHAR ApicId;
+    ULONG Flags;
+} ACPI_LOCAL_APIC;
+
+typedef struct PACKED {
+    UCHAR AddressSpaceId;
+    UCHAR RegisterBitWidth;
+    UCHAR RegisterBitOffset;
+    UCHAR Reserved;
+    UQUAD Address;
+} ACPI_GAS;
+
+/*
+ * ACPI Address Space ID definitions for GAS
+ *
+ * See section 5.2.3.2 of the ACPI software programming
+ * manual.
+ *
+ * XXX: 0x0B->0x7E is reserved as well as 0x80->0xBF
+ *      and 0xC0->0xFF is OEM defined. Values other than
+ *      the ones specified below are either garbage or
+ *      OEM specific values.
+ */
+#define ACPI_GAS_SYSMEM   0x00      /* System memory space */
+#define ACPI_GAS_SYSIO    0x01      /* System I/O space */
+#define ACPI_GAS_PCICONF  0x02      /* PCI configuration space */
+#define ACPI_GAS_EC       0x03      /* Embedded controller */
+#define ACPI_GAS_SMBUS    0x04      /* System management bus */
+#define ACPI_GAS_CMOS     0x05      /* System CMOS */
+#define ACPI_GAS_PCIBAR   0x06      /* PCI BAR target */
+#define ACPI_GAS_IPMI     0x07      /* IPMI (sensor monitoring) */
+#define ACPI_GAS_GPIO     0x08      /* General Purpose I/O */
+#define ACPI_GAS_GSBUS    0x09      /* GenericSerialBus */
+#define ACPI_GAS_PLATCOM  0x0A      /* Platform Communications Channel */
+
+/*
+ * ACPI address size definitions for GAS
+ *
+ * See section 5.2.3.2 of the ACPI software programming
+ * manual.
+ */
+#define ACPI_GAS_UNDEF  0   /* Undefined (legacy reasons) */
+#define ACPI_GAS_BYTE   1   /* Byte access */
+#define ACPI_GAS_WORD   2   /* Word access */
+#define ACPI_GAS_DWORD  3   /* Dword access */
+#define ACPI_GAS_QWORD  4   /* Qword access */
+
+typedef struct PACKED {
+    ACPI_HEADER Header;
+    UCHAR HardwareRevId;
+    UCHAR ComparatorCount   : 5;
+    UCHAR CounterSize       : 1;
+    UCHAR Reserved          : 1;
+    UCHAR LegacyReplacement : 1;
+    USHORT PciVendorId;
+    ACPI_GAS Gas;
+    UCHAR HpetNumber;
+    USHORT MinimumTick;
+    UCHAR PageProtection;
+} ACPI_HPET;
+
+#endif  /* _ACPI_TABLES_H_ */

service/ptos/ke/init.c

@@ -16,6 +16,7 @@
 #include <hal/serial.h>
 #include <hal/kpcr.h>
 #include <drivers/bootvid/fbio.h>
+#include <drivers/acpi/acpi.h>
 #include <string.h>
 
 /* Globals */
@@ -89,6 +90,9 @@ KiKernelInit(VOID)
     /* Phase 2 init of bootstrap core */
     HalKpcrP2Init(&BootstrapCore);
 
+    /* Initialize ACPI */
+    AcpiInit();
+
     /* Initialize the root process */
     InitializeRootProcess();
 }