From 327f63f3a90dce374d9291f67f4d1a4cfd4987b0 Mon Sep 17 00:00:00 2001
From: Adrien Bourmault <neox@os-k.eu>
Date: Mon, 3 Feb 2020 15:34:20 +0100
Subject: [PATCH] RSDT detection successfull

---
 include/io/acpi.h       | 29 +++++++++++++++++++--
 include/kernel.h        |  1 +
 kaleid/kernel/io/acpi.c | 58 ++++++++++++++++++++++++++++++++++++++---
 3 files changed, 83 insertions(+), 5 deletions(-)

diff --git a/include/io/acpi.h b/include/io/acpi.h
index 3228584..41b8d7c 100644
--- a/include/io/acpi.h
+++ b/include/io/acpi.h
@@ -32,20 +32,45 @@
 //----------------------------------------------------------------------------//
 
 //
-// ACPI 2.0 Legacy descriptor
+// ACPI 1.0 descriptor
 //
-struct RSDPDescriptor {
+struct RSDPLegacy {
     char signature[8];
     uchar checksum;
     char OEMID[6];
     uchar revision;
     uint rsdtAddress;
+} __attribute__ ((packed));
+
+//
+// ACPI 2.0 descriptor
+//
+struct RSDPDescriptor {
+    // RSDT ACPI 1.0 and above
+    struct RSDPLegacy legacy;
+
+    // RSDT ACPI 2.0
     uint length;
     ulong xsdtAddress;
     uchar extendedChecksum;
     uchar reserved[3];
 } __attribute__ ((packed));
 
+//
+// ACPI System Description Table
+//
+struct SDTHeader {
+  char signature[4];
+  uint length;
+  uchar revision;
+  uchar checksum;
+  char OEMID[6];
+  char OEMTableID[8];
+  uint OEMRevision;
+  uint creatorID;
+  uint creatorRevision;
+};
+
 //----------------------------------------------------------------------------//
 
 void IoTestAcpi(void);
diff --git a/include/kernel.h b/include/kernel.h
index 3c02075..8b9638e 100644
--- a/include/kernel.h
+++ b/include/kernel.h
@@ -57,6 +57,7 @@ typedef struct ISRList_t            ISRList_t;
 typedef struct ISRFrame_t           ISRFrame_t;
 
 typedef struct RSDPDescriptor       RSDPDescriptor;
+typedef struct SDTHeader            SDTHeader;
 
 typedef struct MemoryMap_t          MemoryMap_t;
 typedef struct MapEntry_t           MapEntry_t;
diff --git a/kaleid/kernel/io/acpi.c b/kaleid/kernel/io/acpi.c
index df1f3fb..af65be3 100644
--- a/kaleid/kernel/io/acpi.c
+++ b/kaleid/kernel/io/acpi.c
@@ -25,9 +25,25 @@
 #include <init/boot.h>
 #include <io/vga.h>
 #include <io/acpi.h>
+#include <mm/paging.h>
+
+SDTHeader *AcpiSDHeader = NULL;
+
+static inline char DoChecksum(void *ptr, size_t size,
+                         size_t intermediateSize, ulong reason)
+{
+    char checksum = 0;
+    for (ulong i=0; i < (ulong)size; i++) {
+        if (reason && i > (ulong)intermediateSize)
+            break;
+        checksum += (uchar)((char*)ptr)[i];
+    }
+    return checksum;
+}
 
 void IoTestAcpi(void)
 {
+    uchar checksum = 0;
 
     if (BtFirmwareInfo.romValid)
         KernLog("\tRom Table is valid at %p\n", BtFirmwareInfo.romTable);
@@ -35,14 +51,50 @@ void IoTestAcpi(void)
     if (BtFirmwareInfo.apmValid)
         KernLog("\tApm Table is valid at %p\n", BtFirmwareInfo.apmTable);
 
+    // FIND RSDP
+
     RSDPDescriptor *rsdp = IoFindRSDP();
     if (!rsdp)
-        return;
+        KeStartPanic("ACPI RSDP not found in memory");
 
-    KernLog("\tFound ACPI RSDP (%s) version %d at %p\n",
-            rsdp->OEMID, (uint)rsdp->revision, rsdp
+    // Checksum calculation
+    checksum = DoChecksum(rsdp, (size_t)sizeof(RSDPDescriptor),
+                          (size_t)sizeof(struct RSDPLegacy),
+                          !rsdp->legacy.revision
+                          );
+
+    if (checksum)
+        KeStartPanic("Invalid checksum : %d vs 0", checksum);
+
+    if (rsdp->legacy.revision == 1 || rsdp->legacy.revision >= 3)
+        KeStartPanic("Invalid ACPI Revision : %d", rsdp->legacy.revision);
+
+    KernLog("\tACPI Root System Table (OEM %s) Revision %d at %p\n",
+            rsdp->legacy.OEMID,
+            (uint)rsdp->legacy.revision,
+            rsdp->legacy.rsdtAddress
             );
 
+    AcpiSDHeader = (SDTHeader *)(ulong)rsdp->legacy.rsdtAddress;
+
+    if (rsdp->legacy.revision) {
+        KernLog("\tFound ACPI Extended System Table (OEM %s) Revision %d at %p\n",
+            rsdp->legacy.OEMID,
+            (uint)rsdp->legacy.revision,
+            rsdp->xsdtAddress
+            );
+
+        AcpiSDHeader = (SDTHeader *)rsdp->xsdtAddress;
+    }
+
+    // Map the Table Header
+    for (ulong i = 0; i < (sizeof(AcpiSDHeader)/KPAGESIZE) + 1; i++) {
+
+        MmMapPage((void*)((ulong)(AcpiSDHeader) + i*KPAGESIZE),
+                  (void*)((ulong)(AcpiSDHeader) + i*KPAGESIZE),
+                  PRESENT);
+    }
+
     return;
 }