MIPS: Detect the MSA ASE

This patch adds support for probing the MSAP bit within the Config3
register in order to detect the presence of the MSA ASE. Presence of the
ASE will be indicated in /proc/cpuinfo. The value of the MSA
implementation register will be displayed at boot to aid debugging and
verification of a correct setup, as is done for the FPU.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6430/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index e5e6aaded3dd..f627739eca49 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1208,6 +1208,7 @@ config CPU_MIPS32_R2
         select CPU_HAS_PREFETCH
         select CPU_SUPPORTS_32BIT_KERNEL
         select CPU_SUPPORTS_HIGHMEM
+        select CPU_SUPPORTS_MSA
         select HAVE_KVM
         help
           Choose this option to build a kernel for release 2 or later of the
@@ -1243,6 +1244,7 @@ config CPU_MIPS64_R2
         select CPU_SUPPORTS_64BIT_KERNEL
         select CPU_SUPPORTS_HIGHMEM
         select CPU_SUPPORTS_HUGEPAGES
+        select CPU_SUPPORTS_MSA
         help
           Choose this option to build a kernel for release 2 or later of the
           MIPS64 architecture.  Many modern embedded systems with a 64-bit
@@ -2081,6 +2083,20 @@ config CPU_MICROMIPS
           When this option is enabled the kernel will be built using the
           microMIPS ISA
 
+config CPU_HAS_MSA
+        bool "Support for the MIPS SIMD Architecture"
+        depends on CPU_SUPPORTS_MSA
+        default y
+        help
+          MIPS SIMD Architecture (MSA) introduces 128 bit wide vector registers
+          and a set of SIMD instructions to operate on them. When this option
+          is enabled the kernel will support detection of the MSA ASE. If you
+          know that your kernel will only be running on CPUs which do not
+          support MSA then you may wish to say N here to reduce the size of
+          your kernel.
+
+          If unsure, say Y.
+
 config CPU_HAS_WB
         bool
 
@@ -2146,6 +2162,9 @@ config SYS_SUPPORTS_SMARTMIPS
 config SYS_SUPPORTS_MICROMIPS
         bool
 
+config CPU_SUPPORTS_MSA
+        bool
+
 config ARCH_FLATMEM_ENABLE
         def_bool y
         depends on !NUMA && !CPU_LOONGSON2