libavutil: Detect MMI and MSA flags for MIPS

Add MMI & MSA runtime detection for MIPS.

Basically there are two code pathes. For systems that
natively support CPUCFG instruction or kernel emulated
that instruction, we'll sense this feature from HWCAP and
report the flags according to values grab from CPUCFG. For
systems that have no CPUCFG (or not export it in HWCAP),
we'll parse /proc/cpuinfo instead.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Reviewed-by: Shiyou Yin <yinshiyou-hf@loongson.cn>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

3 files changed, 163 insertions, 1 deletions

diff --git a/libavutil/mips/Makefile b/libavutil/mips/Makefile
index dbfa5aa341..5f8c9b64e9 100644
--- a/libavutil/mips/Makefile
+++ b/libavutil/mips/Makefile
@@ -1 +1 @@
-OBJS += mips/float_dsp_mips.o
+OBJS += mips/float_dsp_mips.o mips/cpu.o
diff --git a/libavutil/mips/cpu.c b/libavutil/mips/cpu.c
new file mode 100644
index 0000000000..59619d54de
--- /dev/null
+++ b/libavutil/mips/cpu.c
@@ -0,0 +1,134 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/cpu.h"
+#include "libavutil/cpu_internal.h"
+#include "config.h"
+#if defined __linux__ || defined __ANDROID__
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/auxv.h>
+#include "asmdefs.h"
+#include "libavutil/avstring.h"
+#endif
+
+#if defined __linux__ || defined __ANDROID__
+
+#define HWCAP_LOONGSON_CPUCFG (1 << 14)
+
+static int cpucfg_available(void)
+{
+    return getauxval(AT_HWCAP) & HWCAP_LOONGSON_CPUCFG;
+}
+
+/* Most toolchains have no CPUCFG support yet */
+static uint32_t read_cpucfg(uint32_t reg)
+{
+        uint32_t __res;
+
+        __asm__ __volatile__(
+                "parse_r __res,%0\n\t"
+                "parse_r reg,%1\n\t"
+                ".insn \n\t"
+                ".word (0xc8080118 | (reg << 21) | (__res << 11))\n\t"
+                :"=r"(__res)
+                :"r"(reg)
+                :
+                );
+        return __res;
+}
+
+#define LOONGSON_CFG1 0x1
+
+#define LOONGSON_CFG1_MMI    (1 << 4)
+#define LOONGSON_CFG1_MSA1   (1 << 5)
+
+static int cpu_flags_cpucfg(void)
+{
+    int flags = 0;
+    uint32_t cfg1 = read_cpucfg(LOONGSON_CFG1);
+
+    if (cfg1 & LOONGSON_CFG1_MMI)
+        flags |= AV_CPU_FLAG_MMI;
+
+    if (cfg1 & LOONGSON_CFG1_MSA1)
+        flags |= AV_CPU_FLAG_MSA;
+
+    return flags;
+}
+
+static int cpu_flags_cpuinfo(void)
+{
+    FILE *f = fopen("/proc/cpuinfo", "r");
+    char buf[200];
+    int flags = 0;
+
+    if (!f)
+        return -1;
+
+    while (fgets(buf, sizeof(buf), f)) {
+        /* Legacy kernel may not export MMI in ASEs implemented */
+        if (av_strstart(buf, "cpu model", NULL)) {
+            if (strstr(buf, "Loongson-3 "))
+                flags |= AV_CPU_FLAG_MMI;
+        }
+
+        if (av_strstart(buf, "ASEs implemented", NULL)) {
+            if (strstr(buf, " loongson-mmi"))
+                flags |= AV_CPU_FLAG_MMI;
+            if (strstr(buf, " msa"))
+                flags |= AV_CPU_FLAG_MSA;
+
+            break;
+        }
+    }
+    fclose(f);
+    return flags;
+}
+#endif
+
+int ff_get_cpu_flags_mips(void)
+{
+#if defined __linux__ || defined __ANDROID__
+    if (cpucfg_available())
+        return cpu_flags_cpucfg();
+    else
+        return cpu_flags_cpuinfo();
+#else
+    /* Assume no SIMD ASE supported */
+    return 0;
+#endif
+}
+
+size_t ff_get_cpu_max_align_mips(void)
+{
+    int flags = av_get_cpu_flags();
+
+    if (flags & AV_CPU_FLAG_MSA)
+        return 16;
+
+    /*
+     * MMI itself is 64-bit but quad word load & store
+     * needs 128-bit align.
+     */
+    if (flags & AV_CPU_FLAG_MMI)
+        return 16;
+
+    return 8;
+}
diff --git a/libavutil/mips/cpu.h b/libavutil/mips/cpu.h
new file mode 100644
index 0000000000..615dc49759
--- /dev/null
+++ b/libavutil/mips/cpu.h
@@ -0,0 +1,28 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVUTIL_MIPS_CPU_H
+#define AVUTIL_MIPS_CPU_H
+
+#include "libavutil/cpu.h"
+#include "libavutil/cpu_internal.h"
+
+#define have_mmi(flags) CPUEXT(flags, MMI)
+#define have_msa(flags) CPUEXT(flags, MSA)
+
+#endif /* AVUTIL_MIPS_CPU_H */