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, 3 insertions, 2 deletions

diff --git a/arch/mips/loongson/Kconfig b/arch/mips/loongson/Kconfig
index 8b5cc138611a..7a86987b478f 100644
--- a/arch/mips/loongson/Kconfig
+++ b/arch/mips/loongson/Kconfig
@@ -34,10 +34,10 @@ config LEMOTE_MACH2F
         select ARCH_SPARSEMEM_ENABLE
         select BOARD_SCACHE
         select BOOT_ELF32
-        select CEVT_R4K
+        select CEVT_R4K if ! MIPS_EXTERNAL_TIMER
         select CPU_HAS_WB
         select CS5536
-        select CSRC_R4K
+        select CSRC_R4K if ! MIPS_EXTERNAL_TIMER
         select DMA_NONCOHERENT
         select GENERIC_HARDIRQS_NO__DO_IRQ
         select GENERIC_ISA_DMA_SUPPORT_BROKEN
@@ -65,6 +65,7 @@ config CS5536
 config CS5536_MFGPT
         bool "CS5536 MFGPT Timer"
         depends on CS5536
+        select MIPS_EXTERNAL_TIMER
         help
           This option enables the mfgpt0 timer of AMD CS5536.