GK SDK 源码库: XMIPCLinuxV100R005C00SPC030 (kernel/tools/open_source excluded)

2026-09-06 03:52:57 +08:00
commit b1928b41c0
21813 changed files with 4413081 additions and 0 deletions
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2004
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ */
+
+#include <common.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#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(long *base, long maxsize)
+{
+	volatile long *addr;
+	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) {
+		addr = base + cnt;	/* pointer arith! */
+		sync();
+		save[i++] = *addr;
+		sync();
+		*addr = ~cnt;
+	}
+
+	addr = base;
+	sync();
+	save_base = *addr;
+	sync();
+	*addr = 0;
+
+	sync();
+	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];
+		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];
+			}
+			/* 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);
+		}
+	}
+	*base = save_base;
+
+	return (maxsize);
+}
+
+phys_size_t __weak get_effective_memsize(void)
+{
+#ifndef CONFIG_VERY_BIG_RAM
+	return gd->ram_size;
+#else
+	/* limit stack to what we can reasonable map */
+	return ((gd->ram_size > CONFIG_MAX_MEM_MAPPED) ?
+		CONFIG_MAX_MEM_MAPPED : gd->ram_size);
+#endif
+}