From 9f52833adba922a03124870792cab74c78fb5d9b Mon Sep 17 00:00:00 2001
From: Adrien Bourmault <neox@os-k.eu>
Date: Mon, 3 Feb 2020 11:58:34 +0100
Subject: [PATCH] ACPI RSDT detected !

---
 include/io/acpi.h           | 18 +++++++++++++
 include/kernel.h            |  2 ++
 kaleid/kernel/init/init.c   |  6 ++---
 kaleid/kernel/io/acpi.c     | 52 +++++++++++++++++++++++++++++++++++++
 kaleid/kernel/sh/testcmds.c |  1 -
 5 files changed, 75 insertions(+), 4 deletions(-)

diff --git a/include/io/acpi.h b/include/io/acpi.h
index 9b2d087..3228584 100644
--- a/include/io/acpi.h
+++ b/include/io/acpi.h
@@ -31,7 +31,25 @@
 
 //----------------------------------------------------------------------------//
 
+//
+// ACPI 2.0 Legacy descriptor
+//
+struct RSDPDescriptor {
+    char signature[8];
+    uchar checksum;
+    char OEMID[6];
+    uchar revision;
+    uint rsdtAddress;
+    uint length;
+    ulong xsdtAddress;
+    uchar extendedChecksum;
+    uchar reserved[3];
+} __attribute__ ((packed));
+
+//----------------------------------------------------------------------------//
+
 void IoTestAcpi(void);
+RSDPDescriptor *IoFindRSDP(void);
 
 //----------------------------------------------------------------------------//
 
diff --git a/include/kernel.h b/include/kernel.h
index 8000b3d..3c02075 100644
--- a/include/kernel.h
+++ b/include/kernel.h
@@ -56,6 +56,8 @@ typedef struct IdtPtr_t             IdtPtr_t;
 typedef struct ISRList_t            ISRList_t;
 typedef struct ISRFrame_t           ISRFrame_t;
 
+typedef struct RSDPDescriptor       RSDPDescriptor;
+
 typedef struct MemoryMap_t          MemoryMap_t;
 typedef struct MapEntry_t           MapEntry_t;
 typedef struct GdtEntry_t           GdtEntry_t;
diff --git a/kaleid/kernel/init/init.c b/kaleid/kernel/init/init.c
index fb5841d..5855162 100644
--- a/kaleid/kernel/init/init.c
+++ b/kaleid/kernel/init/init.c
@@ -64,6 +64,9 @@ noreturn void BtStartKern(multiboot_info_t *mbInfo, uint mbMagic, void *codeSeg)
     // Sanity checks
     BtDoSanityChecks(mbMagic);
 
+    // ACPI
+    IoTestAcpi();
+
     // Memory
     MmInitMemoryMap();
     MmInitGdt();
@@ -83,9 +86,6 @@ noreturn void BtStartKern(multiboot_info_t *mbInfo, uint mbMagic, void *codeSeg)
     KeGetCpuInfos();
     IoEnableKeyb();
 
-    // ACPI
-    IoTestAcpi();
-
     // Scheduler
     PsInitSched();
 
diff --git a/kaleid/kernel/io/acpi.c b/kaleid/kernel/io/acpi.c
index b5fdd6a..df1f3fb 100644
--- a/kaleid/kernel/io/acpi.c
+++ b/kaleid/kernel/io/acpi.c
@@ -24,6 +24,7 @@
 
 #include <init/boot.h>
 #include <io/vga.h>
+#include <io/acpi.h>
 
 void IoTestAcpi(void)
 {
@@ -34,6 +35,57 @@ void IoTestAcpi(void)
     if (BtFirmwareInfo.apmValid)
         KernLog("\tApm Table is valid at %p\n", BtFirmwareInfo.apmTable);
 
+    RSDPDescriptor *rsdp = IoFindRSDP();
+    if (!rsdp)
+        return;
+
+    KernLog("\tFound ACPI RSDP (%s) version %d at %p\n",
+            rsdp->OEMID, (uint)rsdp->revision, rsdp
+            );
 
     return;
 }
+
+RSDPDescriptor *IoFindRSDP()
+{
+    char *rsdp = NULL;
+
+
+    // Search in EBDA
+    for (rsdp = (char *)0x00080000;   // EBDA address
+         (ulong)rsdp < (ulong)0x0009FFFF;             // EBDA end
+         rsdp++) {
+
+            if (rsdp[0] == 'R' &&
+                rsdp[1] == 'S' &&
+                rsdp[2] == 'D' &&
+                rsdp[3] == ' ' &&
+                rsdp[4] == 'P' &&
+                rsdp[5] == 'T' &&
+                rsdp[6] == 'R' &&
+                rsdp[7] == ' '
+                ) {
+                return (RSDPDescriptor *)rsdp;
+            }
+        }
+
+    // Search in BDA
+    for (rsdp = (char *)0x000E0000;   // BDA address
+         (ulong)rsdp < (ulong)0x000FFFFF;             // BDA end
+         rsdp++) {
+
+            if (rsdp[0] == 'R' &&
+                rsdp[1] == 'S' &&
+                rsdp[2] == 'D' &&
+                rsdp[3] == ' ' &&
+                rsdp[4] == 'P' &&
+                rsdp[5] == 'T' &&
+                rsdp[6] == 'R' &&
+                rsdp[7] == ' '
+                ) {
+                return (RSDPDescriptor *)rsdp;
+            }
+        }
+
+    return NULL;
+}
diff --git a/kaleid/kernel/sh/testcmds.c b/kaleid/kernel/sh/testcmds.c
index 1f7c376..cc322a7 100644
--- a/kaleid/kernel/sh/testcmds.c
+++ b/kaleid/kernel/sh/testcmds.c
@@ -143,7 +143,6 @@ error_t CmdDumpMem(int argc, char **argv, char *cmdline)
         x += step;
     }
 
-    KernLog("\n\n");
     return EOK;
 }