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authorwdenk <wdenk>2004-01-06 22:38:14 +0000
committerwdenk <wdenk>2004-01-06 22:38:14 +0000
commitc83bf6a2d00ef846c1fb2b0c60540f03ef203125 (patch)
treee410334c86d491dbbec765a5765eef9cccd3135a /common/memsize.c
parentb299e41a0d34bf96202d9bbb72739bdd9414b0cc (diff)
downloadbarebox-c83bf6a2d00ef846c1fb2b0c60540f03ef203125.tar.gz
Add a common get_ram_size() function and modify the the
board-specific files to invoke that common implementation.
Diffstat (limited to 'common/memsize.c')
-rw-r--r--common/memsize.c77
1 files changed, 77 insertions, 0 deletions
diff --git a/common/memsize.c b/common/memsize.c
new file mode 100644
index 0000000..dbc812d
--- /dev/null
+++ b/common/memsize.c
@@ -0,0 +1,77 @@
+/*
+ * (C) Copyright 2004
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+
+/*
+ * 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)
+{
+ volatile long *addr;
+ long save[32];
+ long cnt;
+ long val;
+ long size;
+ int i = 0;
+
+ for (cnt = (maxsize / sizeof (long)) >> 1; cnt > 0; cnt >>= 1) {
+ addr = base + cnt; /* pointer arith! */
+ save[i++] = *addr;
+ *addr = ~cnt;
+ }
+
+ addr = base;
+ save[i] = *addr;
+ *addr = 0;
+
+ if ((val = *addr) != 0) {
+ /* Restore the original data before leaving the function.
+ */
+ *addr = save[i];
+ for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
+ addr = base + cnt;
+ *addr = save[--i];
+ }
+ return (0);
+ }
+
+ for (cnt = 1; cnt < maxsize / sizeof (long); cnt <<= 1) {
+ addr = base + cnt; /* pointer arith! */
+ val = *addr;
+ *addr = save[--i];
+ if (val != ~cnt) {
+ size = cnt * sizeof (long);
+ /* Restore the original data before leaving the function.
+ */
+ for (cnt <<= 1; cnt < maxsize / sizeof (long); cnt <<= 1) {
+ addr = base + cnt;
+ *addr = save[--i];
+ }
+ return (size);
+ }
+ }
+
+ return (maxsize);
+}