MIPS: Loongson: Cleanup of the environment variables

Changes:

	o Move bus_clock into prom_init_env()
	o Initialize the cpu_clock_freq to the default values for the
	correspoding processor revisions if no such environment variable
	passed by BIOS/Bootloader.

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: yanh@lemote.com
Cc: huhb@lemote.com
Cc: zhangfx@lemote.com
Patchwork: http://patchwork.linux-mips.org/patch/826/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/mach-loongson/loongson.h

@@ -23,7 +23,7 @@ extern void mach_prepare_reboot(void);
 extern void mach_prepare_shutdown(void);
 
 /* environment arguments from bootloader */
-extern unsigned long bus_clock, cpu_clock_freq;
+extern unsigned long cpu_clock_freq;
 extern unsigned long memsize, highmemsize;
 
 /* loongson-specific command line, env and memory initialization */

arch/mips/loongson/common/env.c

@@ -23,13 +23,10 @@
 
 #include <loongson.h>
 
-unsigned long bus_clock, cpu_clock_freq;
+unsigned long cpu_clock_freq;
 EXPORT_SYMBOL(cpu_clock_freq);
 unsigned long memsize, highmemsize;
 
-/* pmon passes arguments in 32bit pointers */
-int *_prom_envp;
-
 #define parse_even_earlier(res, option, p)				\
 do {									\
 	if (strncmp(option, (char *)p, strlen(option)) == 0)		\
@@ -39,6 +36,10 @@ do {									\
 
 void __init prom_init_env(void)
 {
+	/* pmon passes arguments in 32bit pointers */
+	int *_prom_envp;
+	unsigned long bus_clock;
+	unsigned int processor_id;
 	long l;
 
 	/* firmware arguments are initialized in head.S */
@@ -55,6 +56,22 @@ void __init prom_init_env(void)
 	}
 	if (memsize == 0)
 		memsize = 256;
+	if (bus_clock == 0)
+		bus_clock = 66000000;
+	if (cpu_clock_freq == 0) {
+		processor_id = (&current_cpu_data)->processor_id;
+		switch (processor_id & PRID_REV_MASK) {
+		case PRID_REV_LOONGSON2E:
+			cpu_clock_freq = 533080000;
+			break;
+		case PRID_REV_LOONGSON2F:
+			cpu_clock_freq = 797000000;
+			break;
+		default:
+			cpu_clock_freq = 100000000;
+			break;
+		}
+	}
 
 	pr_info("busclock=%ld, cpuclock=%ld, memsize=%ld, highmemsize=%ld\n",
 		bus_clock, cpu_clock_freq, memsize, highmemsize);