[new uImage] Provide ability to restrict region used for boot images

Allow the user to set 'bootm_low' and 'bootm_size' env vars as a way
to restrict what memory range is used for bootm.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Marian Balakowicz <m8@semihalf.com>
diff --git a/common/image.c b/common/image.c
index 0b71811..9e446fa 100644
--- a/common/image.c
+++ b/common/image.c
@@ -132,6 +132,32 @@
 	return (s && (*s == 'n')) ? 0 : 1;
 }
 
+ulong getenv_bootm_low(void)
+{
+	char *s = getenv ("bootm_low");
+	if (s) {
+		ulong tmp = simple_strtoul (s, NULL, 16);
+		return tmp;
+	}
+
+#ifdef CFG_SDRAM_BASE
+	return CFG_SDRAM_BASE;
+#else
+	return 0;
+#endif
+}
+
+ulong getenv_bootm_size(void)
+{
+	char *s = getenv ("bootm_size");
+	if (s) {
+		ulong tmp = simple_strtoul (s, NULL, 16);
+		return tmp;
+	}
+
+	return gd->bd->bi_memsize;
+}
+
 void memmove_wd (void *to, void *from, size_t len, ulong chunksz)
 {
 #if defined(CONFIG_HW_WATCHDOG) || defined(CONFIG_WATCHDOG)