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>
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index e5e6aad..f627739 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1208,6 +1208,7 @@
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 @@
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 @@
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_MICROMIPS
bool
+config CPU_SUPPORTS_MSA
+ bool
+
config ARCH_FLATMEM_ENABLE
def_bool y
depends on !NUMA && !CPU_LOONGSON2
diff --git a/arch/mips/include/asm/cpu-features.h b/arch/mips/include/asm/cpu-features.h
index 6e70b03..390795d 100644
--- a/arch/mips/include/asm/cpu-features.h
+++ b/arch/mips/include/asm/cpu-features.h
@@ -299,4 +299,10 @@
#define cpu_has_vz (cpu_data[0].ases & MIPS_ASE_VZ)
#endif
+#if defined(CONFIG_CPU_HAS_MSA) && !defined(cpu_has_msa)
+# define cpu_has_msa (cpu_data[0].ases & MIPS_ASE_MSA)
+#elif !defined(cpu_has_msa)
+# define cpu_has_msa 0
+#endif
+
#endif /* __ASM_CPU_FEATURES_H */
diff --git a/arch/mips/include/asm/cpu-info.h b/arch/mips/include/asm/cpu-info.h
index 09d7dfc..49953f7 100644
--- a/arch/mips/include/asm/cpu-info.h
+++ b/arch/mips/include/asm/cpu-info.h
@@ -49,6 +49,7 @@
unsigned long ases;
unsigned int processor_id;
unsigned int fpu_id;
+ unsigned int msa_id;
unsigned int cputype;
int isa_level;
int tlbsize;
diff --git a/arch/mips/include/asm/cpu.h b/arch/mips/include/asm/cpu.h
index 559c668..85e4083 100644
--- a/arch/mips/include/asm/cpu.h
+++ b/arch/mips/include/asm/cpu.h
@@ -370,5 +370,6 @@
#define MIPS_ASE_MIPSMT 0x00000020 /* CPU supports MIPS MT */
#define MIPS_ASE_DSP2P 0x00000040 /* Signal Processing ASE Rev 2 */
#define MIPS_ASE_VZ 0x00000080 /* Virtualization ASE */
+#define MIPS_ASE_MSA 0x00000100 /* MIPS SIMD Architecture */
#endif /* _ASM_CPU_H */
diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index c1ee8b4..420d2fc 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -23,6 +23,7 @@
#include <asm/cpu-type.h>
#include <asm/fpu.h>
#include <asm/mipsregs.h>
+#include <asm/msa.h>
#include <asm/watch.h>
#include <asm/elf.h>
#include <asm/spram.h>
@@ -126,6 +127,20 @@
return ((cpu_get_fpu_id() & FPIR_IMP_MASK) != FPIR_IMP_NONE);
}
+static inline unsigned long cpu_get_msa_id(void)
+{
+ unsigned long status, conf5, msa_id;
+
+ status = read_c0_status();
+ __enable_fpu(FPU_64BIT);
+ conf5 = read_c0_config5();
+ enable_msa();
+ msa_id = read_msa_ir();
+ write_c0_config5(conf5);
+ write_c0_status(status);
+ return msa_id;
+}
+
static inline void cpu_probe_vmbits(struct cpuinfo_mips *c)
{
#ifdef __NEED_VMBITS_PROBE
@@ -301,6 +316,8 @@
c->ases |= MIPS_ASE_VZ;
if (config3 & MIPS_CONF3_SC)
c->options |= MIPS_CPU_SEGMENTS;
+ if (config3 & MIPS_CONF3_MSA)
+ c->ases |= MIPS_ASE_MSA;
return config3 & MIPS_CONF_M;
}
@@ -1178,6 +1195,9 @@
else
c->srsets = 1;
+ if (cpu_has_msa)
+ c->msa_id = cpu_get_msa_id();
+
cpu_probe_vmbits(c);
#ifdef CONFIG_64BIT
@@ -1194,4 +1214,6 @@
smp_processor_id(), c->processor_id, cpu_name_string());
if (c->options & MIPS_CPU_FPU)
printk(KERN_INFO "FPU revision is: %08x\n", c->fpu_id);
+ if (cpu_has_msa)
+ pr_info("MSA revision is: %08x\n", c->msa_id);
}
diff --git a/arch/mips/kernel/proc.c b/arch/mips/kernel/proc.c
index 00d2097..ca1d48e 100644
--- a/arch/mips/kernel/proc.c
+++ b/arch/mips/kernel/proc.c
@@ -95,6 +95,7 @@
if (cpu_has_mipsmt) seq_printf(m, "%s", " mt");
if (cpu_has_mmips) seq_printf(m, "%s", " micromips");
if (cpu_has_vz) seq_printf(m, "%s", " vz");
+ if (cpu_has_msa) seq_printf(m, "%s", " msa");
seq_printf(m, "\n");
if (cpu_has_mmips) {