Simplify hwaccess.c

Previously the code was focused on architectures which led to lots of
duplicate code and spread the information regarding differences between
the architectures accross the file.

With this patch there is a single function header for any function and the
differentiation between architectures (and OS where needed) happens
in one place for each function. Also, this patch adds simple defines to bundle
often used arch and os checks. A central check for unknown architectures
and OSes has been added on top.

Corresponding to flashrom svn r1638.

Signed-off-by: Peter Lemenkov <lemenkov@gmail.com>
Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>

hwaccess.c

@@ -18,6 +18,20 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  */
 
+#define IS_X86	(defined(__i386__) || defined(__x86_64__) || defined(__amd64__))
+#define IS_MIPS	(defined (__mips) || defined (__mips__) || defined (__MIPS__) || defined (mips))
+#define IS_PPC	(defined(__powerpc__) || defined(__powerpc64__) || defined(__ppc__) || defined(__ppc64__))
+#define IS_ARM	(defined (__arm__) || defined (_ARM))
+#if !(IS_X86 || IS_MIPS || IS_PPC || IS_ARM)
+#error Unknown architecture
+#endif
+
+#define IS_BSD	(defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__) || defined(__OpenBSD__))
+#define IS_LINUX	(defined(__gnu_linux__) || defined(__linux__))
+#if !(IS_BSD || IS_LINUX || defined(__DJGPP__) || defined(__LIBPAYLOAD__) || defined(__sun))
+#error "Unknown operating system"
+#endif
+
 #include <stdint.h>
 #include <string.h>
 #include <stdlib.h>
@@ -32,30 +46,39 @@
 #include "flash.h"
 #include "hwaccess.h"
 
-#if defined(__i386__) || defined(__x86_64__)
+#if IS_X86 && IS_BSD
-
-/* sync primitive is not needed because x86 uses uncached accesses
- * which have a strongly ordered memory model.
- */
-static inline void sync_primitive(void)
-{
-}
-
-#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__)
 int io_fd;
 #endif
 
-int release_io_perms(void *p)
+/* Prevent reordering and/or merging of reads/writes to hardware.
+ * Such reordering and/or merging would break device accesses which depend on the exact access order.
+ */
+static inline void sync_primitive(void)
 {
+/* This is needed only on PowerPC because...
+ * - x86 uses uncached accesses which have a strongly ordered memory model and
+ * - MIPS uses uncached accesses in mode 2 on /dev/mem which has also a strongly ordered memory model
+ * - ARM uses a strongly ordered memory model for device memories.
+ */
+#if IS_PPC
+	asm("eieio" : : : "memory");
+#endif
+}
+
+static int release_io_perms(void *p)
+{
+#if IS_X86
 #if defined(__DJGPP__) || defined(__LIBPAYLOAD__)
-#else
+	/* Nothing to release */
-#if defined (__sun) && (defined(__i386) || defined(__amd64))
+#elif defined (__sun)
 	sysi86(SI86V86, V86SC_IOPL, 0);
-#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined (__DragonFly__)
+#elif IS_BSD
 	close(io_fd);
-#else 
+#elif IS_LINUX
 	iopl(0);
 #endif
+#else
+/* PCI port I/O support is unimplemented on PPC/MIPS and unavailable on ARM. */
 #endif
 	return 0;
 }
@@ -63,80 +86,31 @@ int release_io_perms(void *p)
 /* Get I/O permissions with automatic permission release on shutdown. */
 int rget_io_perms(void)
 {
+#if IS_X86
 #if defined(__DJGPP__) || defined(__LIBPAYLOAD__)
 	/* We have full permissions by default. */
-	return 0;
+#elif defined (__sun)
-#else
-#if defined (__sun) && (defined(__i386) || defined(__amd64))
 	if (sysi86(SI86V86, V86SC_IOPL, PS_IOPL) != 0) {
-#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined (__DragonFly__)
+#elif IS_BSD
 	if ((io_fd = open("/dev/io", O_RDWR)) < 0) {
-#else 
+#elif IS_LINUX
 	if (iopl(3) != 0) {
 #endif
 		msg_perr("ERROR: Could not get I/O privileges (%s).\n"
 			"You need to be root.\n", strerror(errno));
 #if defined (__OpenBSD__)
-		msg_perr("Please set securelevel=-1 in /etc/rc.securelevel "
+		msg_perr("Please set securelevel=-1 in /etc/rc.securelevel and reboot, or reboot into \n");
-			   "and reboot, or reboot into \n");
 		msg_perr("single user mode.\n");
 #endif
 		return 1;
 	} else {
 		register_shutdown(release_io_perms, NULL);
 	}
-	return 0;
-#endif
-}
-
-#elif defined(__powerpc__) || defined(__powerpc64__) || defined(__ppc__) || defined(__ppc64__)
-
-static inline void sync_primitive(void)
-{
-	/* Prevent reordering and/or merging of reads/writes to hardware.
-	 * Such reordering and/or merging would break device accesses which
-	 * depend on the exact access order.
-	 */
-	___asm___ volatile ("eieio" : : : "memory");
-}
-
-/* PCI port I/O is not yet implemented on PowerPC. */
-int rget_io_perms(void)
-{
-	return 0;
-}
-
-#elif defined (__mips) || defined (__mips__) || defined (_mips) || defined (mips)
-
-/* sync primitive is not needed because /dev/mem on MIPS uses uncached accesses
- * in mode 2 which has a strongly ordered memory model.
- */
-static inline void sync_primitive(void)
-{
-}
-
-/* PCI port I/O is not yet implemented on MIPS. */
-int rget_io_perms(void)
-{
-	return 0;
-}
-
-#elif defined (__arm__)
-
-static inline void sync_primitive(void)
-{
-}
-
-int rget_io_perms(void)
-{
-	return 0;
-}
-
 #else
-
+/* PCI port I/O support is unimplemented on PPC/MIPS and unavailable on ARM. */
-#error Unknown architecture
-
 #endif
+	return 0;
+}
 
 void mmio_writeb(uint8_t val, void *addr)
 {