Initial work for the in-memory disk emulator

1 files changed, 183 insertions, 0 deletions

diff --git a/memdisk/msetup.c b/memdisk/msetup.c
new file mode 100644
index 00000000..c37169be
--- /dev/null
+++ b/memdisk/msetup.c
@@ -0,0 +1,183 @@
+#ident "$Id$"
+/* ----------------------------------------------------------------------- *
+ *   
+ *   Copyright 2001 H. Peter Anvin - All Rights Reserved
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Bostom MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * msetup.c
+ *
+ * Initialization code for memory-based disk
+ */
+
+#include <stdint.h>
+#include "e820.h"
+
+static inline int get_e820(void)
+{
+  struct e820_info {
+    uint64_t base;
+    uint64_t len;
+    uint32_t type;
+  } __attribute__((packed));
+  struct e820_info buf;
+  uint32_t lastptr = 0;
+  int copied;
+  int range_count;
+  
+  do {
+    asm volatile("int $0x15 ; "
+		 "jc 1f ; "
+		 "cmpl $0x534d4150, %%eax ; "
+		 "je 2f\n"
+		 "1:\n\t"
+		 "xorl %%ecx, %%ecx\n"
+		 "2:"
+		 : "=c" (copied), "=&b" (lastptr)
+		 : "a" (0x0000e820), "d" (0x534d4150),
+		 "c" (20), "D" (&buf)
+		 : "esi", "ebp");
+
+    if ( copied < 20 )
+      break;
+
+    insertrange(buf.base, buf.len, buf.type);
+    range_count++;
+
+  } while ( lastptr );
+
+  return !range_count;
+}
+
+static inline void get_dos_mem(void)
+{
+  uint16_t dos_kb;
+
+  asm volatile("int $0x12" : "=a" (dos_kb)
+	       :: "ebx", "ecx", "edx", "esi", "edi", "ebp");
+  
+  insertrange(0, (uint64_t)((uint32_t)dos_kb << 10), 1);
+}
+
+static inline int get_e881(void)
+{
+  uint32_t low_mem;
+  uint32_t high_mem;
+  uint8_t err;
+
+  asm volatile("movw $0xe881, %%ax ; "
+	       "int $0x15 ; "
+	       "setc %2"
+	       : "=a" (low_mem), "=b" (high_mem), "=d" (err)
+	       :: "ecx", "esi", "edi", "ebp");
+
+  if ( !err ) {
+    if ( low_mem ) {
+      insertrange(0x100000, (uint64_t)low_mem << 10, 1);
+    }
+    if ( high_mem ) {
+      insertrange(0x1000000, (uint64_t)high_mem << 16, 1);
+    }
+  }
+
+  return err;
+}
+
+static inline int get_e801(void)
+{
+  uint16_t low_mem;
+  uint16_t high_mem;
+  uint8_t err;
+
+  asm volatile("movw $0xe801, %%ax ; "
+	       "int $0x15 ; "
+	       "setc %2"
+	       : "=a" (low_mem), "=b" (high_mem), "=d" (err)
+	       :: "ecx", "esi", "edi", "ebp");
+
+  if ( !err ) {
+    if ( low_mem ) {
+      insertrange(0x100000, (uint64_t)((uint32_t)low_mem << 10), 1);
+    }
+    if ( high_mem ) {
+      insertrange(0x1000000, (uint64_t)((uint32_t)high_mem << 16), 1);
+    }
+  }
+
+  return err;
+}
+
+static inline int get_88(void)
+{
+  uint16_t low_mem;
+  uint8_t err;
+
+  asm volatile("movb $0x88,%%ah ; "
+	       "int $0x15 ; "
+	       "setc %1"
+	       : "=a" (low_mem), "=d" (err)
+	       :: "ebx", "ecx", "esi", "edi", "ebp");
+
+  if ( !err ) {
+    if ( low_mem ) {
+      insertrange(0x100000, (uint64_t)((uint32_t)low_mem << 10), 1);
+    }
+  }
+
+  return err;
+}
+
+uint32_t dos_mem  = 0;		/* 0-1MB */
+uint32_t low_mem  = 0;		/* 1-16MB */
+uint32_t high_mem = 0;		/* 16+ MB */
+
+void get_mem(void)
+{
+  if ( get_e820() ) {
+    get_dos_mem();
+    if ( get_e881() ) {
+      if ( get_e801() ) {
+	if ( get_88() ) {
+	  /* Running out of ideas here... */
+	}
+      }
+    }
+  }
+}
+
+void parse_mem(void)
+{
+  struct e820range *ep;
+
+  /* Derive "dos mem", "high mem", and "low mem" from the range array */
+  for ( ep = ranges ; ep->type != -1 ; ep++ ) {
+    if ( ep->type == 1 ) {
+      /* Only look at memory ranges */
+      if ( ep->start == 0 ) {
+	if ( ep[1].start > 0x100000 )
+	  dos_mem = 0x100000;
+	else
+	  dos_mem = ep[1].start;
+      }
+      if ( ep->start <= 0x100000 && ep[1].start > 0x100000 ) {
+	if ( ep[1].start > 0x1000000 )
+	  low_mem = 0x1000000 - ep->start;
+	else
+	  low_mem = ep[1].start - ep->start;
+      }
+      if ( ep->start <= 0x1000000 && ep[1].start > 0x1000000 ) {
+	if ( ep[1].start > 0x100000000 )
+	  high_mem = 0x100000000 - ep->start;
+	else
+	  high_mem = ep[1].start - ep->start;
+      }
+    }
+  }
+}