MIPS: Loongson 2F: Add CPU frequency scaling support

Loongson 2F supports CPU clock scaling. When put it into wait mode by
setting the frequency as ZERO it will stay in this mode until an external
interrupt wakes the CPU again.

To enable clock scaling support, an external timer of a known stable rate
is required.

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: cpufreq@vger.kernel.org,
Cc: Dave Jones <davej@redhat.com>,
Cc: Dominik Brodowski <linux@dominikbrodowski.net>,
Cc: yanh@lemote.com
Cc: huhb@lemote.com,
Patchwork: http://patchwork.linux-mips.org/patch/660/
Patchwork: http://patchwork.linux-mips.org/patch/751/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/mips/include/asm/cpu.h b/arch/mips/include/asm/cpu.h
index 4b96d1a36056..cf373a95fe4a 100644
--- a/arch/mips/include/asm/cpu.h
+++ b/arch/mips/include/asm/cpu.h
@@ -154,6 +154,8 @@
 #define PRID_REV_VR4181A        0x0070  /* Same as VR4122 */
 #define PRID_REV_VR4130         0x0080
 #define PRID_REV_34K_V1_0_2     0x0022
+#define PRID_REV_LOONGSON2E     0x0002
+#define PRID_REV_LOONGSON2F     0x0003
 
 /*
  * Older processors used to encode processor version and revision in two