+/*
+ * arch_mem_init - initialize memory managment subsystem
+ *
+ * o plat_mem_setup() detects the memory configuration and will record detected
+ * memory areas using add_memory_region.
+ *
+ * At this stage the memory configuration of the system is known to the
+ * kernel but generic memory managment system is still entirely uninitialized.
+ *
+ * o bootmem_init()
+ * o sparse_init()
+ * o paging_init()
+ *
+ * At this stage the bootmem allocator is ready to use.
+ *
+ * NOTE: historically plat_mem_setup did the entire platform initialization.
+ * This was rather impractical because it meant plat_mem_setup had to
+ * get away without any kind of memory allocator. To keep old code from
+ * breaking plat_setup was just renamed to plat_setup and a second platform
+ * initialization hook for anything else was introduced.
+ */
+
+static int usermem __initdata = 0;
+
+static int __init early_parse_mem(char *p)
+{
+ unsigned long start, size;
+
+ /*
+ * If a user specifies memory size, we
+ * blow away any automatically generated
+ * size.
+ */
+ if (usermem == 0) {
+ boot_mem_map.nr_map = 0;
+ usermem = 1;
+ }
+ start = 0;
+ size = memparse(p, &p);
+ if (*p == '@')
+ start = memparse(p + 1, &p);
+
+ add_memory_region(start, size, BOOT_MEM_RAM);
+ return 0;
+}
+early_param("mem", early_parse_mem);
+
+static void __init arch_mem_init(char **cmdline_p)
+{
+ extern void plat_mem_setup(void);
+
+ /* call board setup routine */
+ plat_mem_setup();
+
+ printk("Determined physical RAM map:\n");
+ print_memory_map();
+
+ strlcpy(command_line, arcs_cmdline, sizeof(command_line));
+ strlcpy(saved_command_line, command_line, COMMAND_LINE_SIZE);
+
+ *cmdline_p = command_line;
+
+ parse_early_param();
+
+ if (usermem) {
+ printk("User-defined physical RAM map:\n");
+ print_memory_map();