LibBareMetal: Creating a new library for freestanding environments

Libraries/LibBareMetal/IO.h

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+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/Types.h>
+
+#if defined(KERNEL)
+#    include <Kernel/Arch/i386/CPU.h>
+#    include <Kernel/Devices/VMWareBackdoor.h>
+#endif
+
+namespace IO {
+
+inline u8 in8(u16 port)
+{
+    u8 value;
+    asm volatile("inb %1, %0"
+                 : "=a"(value)
+                 : "Nd"(port));
+    return value;
+}
+
+inline u16 in16(u16 port)
+{
+    u16 value;
+    asm volatile("inw %1, %0"
+                 : "=a"(value)
+                 : "Nd"(port));
+    return value;
+}
+
+inline u32 in32(u16 port)
+{
+    u32 value;
+    asm volatile("inl %1, %0"
+                 : "=a"(value)
+                 : "Nd"(port));
+    return value;
+}
+
+inline void repeated_in16(u16 port, u8* buffer, int buffer_size)
+{
+    asm volatile("rep insw"
+                 : "+D"(buffer), "+c"(buffer_size)
+                 : "d"(port)
+                 : "memory");
+}
+
+inline void out8(u16 port, u8 value)
+{
+    asm volatile("outb %0, %1" ::"a"(value), "Nd"(port));
+}
+
+inline void out16(u16 port, u16 value)
+{
+    asm volatile("outw %0, %1" ::"a"(value), "Nd"(port));
+}
+
+inline void out32(u16 port, u32 value)
+{
+    asm volatile("outl %0, %1" ::"a"(value), "Nd"(port));
+}
+
+inline void repeated_out16(u16 port, const u8* data, int data_size)
+{
+    asm volatile("rep outsw"
+                 : "+S"(data), "+c"(data_size)
+                 : "d"(port));
+}
+
+inline void delay()
+{
+    // ~3 microsecs
+    for (auto i = 0; i < 32; i++) {
+        IO::in8(0x80);
+    }
+}
+
+}