+// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2004
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
- *
- * SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
long get_ram_size(long *base, long maxsize)
{
volatile long *addr;
- long save[32];
+ long save[BITS_PER_LONG - 1];
+ long save_base;
long cnt;
long val;
long size;
int i = 0;
- for (cnt = (maxsize / sizeof(long)) >> 1; cnt >= 0; cnt >>= 1) {
+ for (cnt = (maxsize / sizeof(long)) >> 1; cnt > 0; cnt >>= 1) {
addr = base + cnt; /* pointer arith! */
sync();
- save[i] = *addr;
+ save[i++] = *addr;
sync();
- if (cnt) {
- i++;
- *addr = ~cnt;
- } else {
- *addr = 0;
- }
+ *addr = ~cnt;
}
+ addr = base;
+ sync();
+ save_base = *addr;
+ sync();
+ *addr = 0;
+
sync();
- cnt = 0;
- do {
+ if ((val = *addr) != 0) {
+ /* Restore the original data before leaving the function. */
+ sync();
+ *base = save_base;
+ for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
+ addr = base + cnt;
+ sync();
+ *addr = save[--i];
+ }
+ return (0);
+ }
+
+ for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
addr = base + cnt; /* pointer arith! */
val = *addr;
- *addr = save[i--];
- sync();
- if (((cnt == 0) && (val != 0)) ||
- ((cnt != 0) && (val != ~cnt))) {
+ *addr = save[--i];
+ if (val != ~cnt) {
size = cnt * sizeof(long);
/*
* Restore the original data
cnt < maxsize / sizeof(long);
cnt <<= 1) {
addr = base + cnt;
- *addr = save[i--];
+ *addr = save[--i];
}
+ /* warning: don't restore save_base in this case,
+ * it is already done in the loop because
+ * base and base+size share the same physical memory
+ * and *base is saved after *(base+size) modification
+ * in first loop
+ */
return (size);
}
-
- if (cnt)
- cnt = cnt << 1;
- else
- cnt = 1;
- } while (cnt < maxsize / sizeof(long));
+ }
+ *base = save_base;
return (maxsize);
}