* MA 02111-1307 USA
*/
+#include <config.h>
+#ifdef __PPC__
+/*
+ * At least on G2 PowerPC cores, sequential accesses to non-existent
+ * memory must be synchronized.
+ */
+# include <asm/io.h> /* for sync() */
+#else
+# define sync() /* nothing */
+#endif
/*
* Check memory range for valid RAM. A simple memory test determines
* the actually available RAM size between addresses `base' and
* `base + maxsize'.
*/
-long get_ram_size(volatile long *base, long maxsize)
+long get_ram_size(long *base, long maxsize)
{
volatile long *addr;
long save[32];
for (cnt = (maxsize / sizeof (long)) >> 1; cnt > 0; cnt >>= 1) {
addr = base + cnt; /* pointer arith! */
+ sync ();
save[i++] = *addr;
+ sync ();
*addr = ~cnt;
}
addr = base;
+ sync ();
save[i] = *addr;
+ sync ();
*addr = 0;
+ sync ();
if ((val = *addr) != 0) {
/* Restore the original data before leaving the function.
*/
+ sync ();
*addr = save[i];
for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
addr = base + cnt;
+ sync ();
*addr = save[--i];
}
return (0);