From 9d9515c39934e194abfc54f938696cc626247922 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20Lov=C3=A9n?= <thomasloven@gmail.com>
Date: Fri, 23 Feb 2018 22:19:47 +0100
Subject: [PATCH] Read and save data from MADT

---
 src/kernel/drivers/acpi.c | 71 +++++++++++++++++++++++++++++++++++++++
 src/kernel/include/smp.h  | 23 +++++++++++++
 2 files changed, 94 insertions(+)

diff --git a/src/kernel/drivers/acpi.c b/src/kernel/drivers/acpi.c
index 8ee5c0c..17368f9 100644
--- a/src/kernel/drivers/acpi.c
+++ b/src/kernel/drivers/acpi.c
@@ -29,6 +29,43 @@ struct sdt
   uint8_t data[];
 }__attribute__((packed));
 
+struct madt
+{
+  uint32_t lic_address;
+  uint32_t flags;
+  uint8_t data[];
+}__attribute__((packed));
+struct madt_entry
+{
+  uint8_t type;
+  uint8_t len;
+  union{
+    struct {
+      uint8_t id;
+      uint8_t apic;
+      uint32_t flags;
+    }__attribute__((packed)) lapic;
+    struct {
+      uint8_t id;
+      uint8_t _;
+      uint32_t addr;
+      uint32_t base;
+    }__attribute__((packed)) ioapic;
+    struct {
+      uint8_t bus;
+      uint8_t source;
+      uint32_t target;
+      uint16_t flags;
+    }__attribute__((packed)) interrupt;
+  };
+}__attribute__((packed));
+
+#define MADT_CPU 0
+#define MADT_IOAPIC 1
+#define MADT_INT 2
+
+struct acpi_info acpi_info = {0};
+
 static struct rsdp *find_rsdp()
 {
   uintptr_t ebda_start = *(uint16_t *)P2V(0x40e);
@@ -59,6 +96,38 @@ static struct rsdp *find_rsdp()
   return 0;
 }
 
+static void parse_madt(struct madt *madt, uint32_t len)
+{
+  uintptr_t end = (uintptr_t)madt + len;
+  struct madt_entry *e = (void *)madt->data;
+  debug_info("Local Interrupt Controller: %x\n", madt->lic_address);
+  while((uintptr_t)e < end)
+  {
+    int i;
+    switch(e->type)
+    {
+      case MADT_CPU:
+        i = acpi_info.num_cpus;
+        acpi_info.cpu[i].id = e->lapic.id;
+        acpi_info.cpu[i].apic = e->lapic.apic;
+        acpi_info.num_cpus++;
+        break;
+      case MADT_IOAPIC:
+        i = acpi_info.num_ioapic;
+        acpi_info.ioapic[i].id = e->ioapic.id;
+        acpi_info.ioapic[i].addr = e->ioapic.addr;
+        acpi_info.ioapic[i].base = e->ioapic.base;
+        acpi_info.num_ioapic++;
+        break;
+      case MADT_INT:
+        acpi_info.int_map[e->interrupt.source] = e->interrupt.target;
+        break;
+    }
+    debug_info(" MADT: type:%d len:%d\n", e->type, e->len);
+    e = incptr(e, e->len);
+  }
+}
+
 static void parse_sdt(struct sdt *sdt, uint8_t revision)
 {
   uint32_t *p32 = (void *)sdt->data;
@@ -70,6 +139,8 @@ static void parse_sdt(struct sdt *sdt, uint8_t revision)
     debug_info("Found table: ");
     debug_putsn((char *)table->signature, 4);
     debug_printf("\n");
+    if(!memcmp(table->signature, "APIC", 4))
+      parse_madt((void *)table->data, table->len);
   }
 }
 
diff --git a/src/kernel/include/smp.h b/src/kernel/include/smp.h
index 2ab42f7..f8450fb 100644
--- a/src/kernel/include/smp.h
+++ b/src/kernel/include/smp.h
@@ -1,3 +1,26 @@
 #pragma once
+#include <stdint.h>
+
+#define MAX_CPUS 16
+#define MAX_IOAPIC 4
+
+struct acpi_info
+{
+  int num_cpus;
+  struct {
+    uint8_t id;
+    uint8_t apic;
+  } cpu[MAX_CPUS];
+
+  int num_ioapic;
+  struct {
+    uint8_t id;
+    uint32_t addr;
+    uint32_t base;
+  } ioapic[MAX_IOAPIC];
+
+  uint32_t int_map[255];
+};
+extern struct acpi_info acpi_info;
 
 void acpi_init();