minios: Add ioread/iowrite functions to mini-os

This patch adds iowritexx() and ioreadxx() functions for interacting
with hardware memory to mini-os. The functions are available in a header
iorw.h

Signed-off-by: Matthew Fioravante <matthew.fioravante@jhuapl.edu>
Acked-by: Samuel Thibault <samuel.thibault@ens-lyons.org>
Reviewed-by: George Dunlap <george.dunlap@eu.citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>

extras/mini-os/arch/x86/iorw.c

@@ -0,0 +1,35 @@
+#include <mini-os/iorw.h>
+
+void iowrite8(volatile void* addr, uint8_t val)
+{
+   *((volatile uint8_t*)addr) = val;
+}
+void iowrite16(volatile void* addr, uint16_t val)
+{
+   *((volatile uint16_t*)addr) = val;
+}
+void iowrite32(volatile void* addr, uint32_t val)
+{
+   *((volatile uint32_t*)addr) = val;
+}
+void iowrite64(volatile void* addr, uint64_t val)
+{
+   *((volatile uint64_t*)addr) = val;
+}
+
+uint8_t ioread8(volatile void* addr)
+{
+   return *((volatile uint8_t*) addr);
+}
+uint16_t ioread16(volatile void* addr)
+{
+   return *((volatile uint16_t*) addr);
+}
+uint32_t ioread32(volatile void* addr)
+{
+   return *((volatile uint32_t*) addr);
+}
+uint64_t ioread64(volatile void* addr)
+{
+   return *((volatile uint64_t*) addr);
+}

extras/mini-os/include/iorw.h

@@ -0,0 +1,16 @@
+#ifndef MINIOS_IORW_H
+#define MINIOS_IORW_H
+
+#include <mini-os/types.h>
+
+void iowrite8(volatile void* addr, uint8_t val);
+void iowrite16(volatile void* addr, uint16_t val);
+void iowrite32(volatile void* addr, uint32_t val);
+void iowrite64(volatile void* addr, uint64_t val);
+
+uint8_t ioread8(volatile void* addr);
+uint16_t ioread16(volatile void* addr);
+uint32_t ioread32(volatile void* addr);
+uint64_t ioread64(volatile void* addr);
+
+#endif