Enable AT_PLATFORM for Loongson 2F CPU.

Signed-off-by: Robert Millan <rmh@gnu.org>

diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index 71620e1..69905d2 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -5,6 +5,7 @@
  * Copyright (C) 1994 - 2006 Ralf Baechle
  * Copyright (C) 2003, 2004  Maciej W. Rozycki
  * Copyright (C) 2001, 2004  MIPS Inc.
+ * Copyright (C) 2010  Robert Millan
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -18,6 +19,7 @@
 #include <linux/stddef.h>
 #include <linux/module.h>
 
+#include <asm/bootinfo.h>
 #include <asm/bugs.h>
 #include <asm/cpu.h>
 #include <asm/fpu.h>
@@ -613,7 +615,30 @@ static inline void cpu_probe_legacy(struct cpuinfo_mips *c, unsigned int cpu)
 		break;
 	case PRID_IMP_LOONGSON2:
 		c->cputype = CPU_LOONGSON2;
-		__cpu_name[cpu] = "ICT Loongson-2";
+		/*
+		 * On Loongson 2, PRID doesn't specify sub-class reliably.
+		 * We use machtype info passed by bootloader, when available,
+		 * or otherwise fallback to generic "ICT Loongson-2".
+		 */
+		switch (mips_machtype) {
+		case MACH_LEMOTE_FL2E:
+			__cpu_name[cpu] = "ICT Loongson-2E";
+			if (cpu == 0)
+				__elf_platform = "loongson2e";
+			break;
+		case MACH_LEMOTE_FL2F:
+		case MACH_LEMOTE_ML2F7:
+		case MACH_LEMOTE_YL2F89:
+		case MACH_DEXXON_GDIUM2F10:
+		case MACH_LEMOTE_NAS:
+		case MACH_LEMOTE_LL2F:
+			__cpu_name[cpu] = "ICT Loongson-2F";
+			if (cpu == 0)
+				__elf_platform = "loongson2f";
+			break;
+		default:
+			__cpu_name[cpu] = "ICT Loongson-2";
+		}
 		c->isa_level = MIPS_CPU_ISA_III;
 		c->options = R4K_OPTS |
 			     MIPS_CPU_FPU | MIPS_CPU_LLSC |
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index acd3f2c..74b8c16 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -551,6 +551,14 @@ void __init setup_arch(char **cmdline_p)
 {
 	cpu_probe();
 	prom_init();
+#ifdef CONFIG_MACH_LOONGSON
+	/*
+	 * On Loongson 2, CPU detection is defective. machtype
+	 * heuristics are used instead, but they only work after
+	 * prom_init().
+	 */
+	cpu_probe();
+#endif
 
 #ifdef CONFIG_EARLY_PRINTK
 	setup_early_printk();