CPU: Added code for runtime CPU features detection

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

src/Makefile.am

@@ -31,6 +31,8 @@ sunxifb_drv_ladir = @moduledir@/drivers
 sunxifb_drv_la_SOURCES = \
          compat-api.h \
          uthash.h \
+         cpuinfo.c \
+         cpuinfo.h \
          fbdev.c \
          fbdev_priv.h \
          sunxi_disp.c \

src/cpuinfo.c

+/*
+ * Copyright © 2013 Siarhei Siamashka <siarhei.siamashka@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "cpuinfo.h"
+
+#if defined(__linux__) || defined(ANDROID) || defined(__ANDROID__)
+
+#define MAXBUFSIZE 16384
+
+static const char *cpuinfo_match_prefix(const char *s, const char *prefix)
+{
+    const char *result;
+    if (strncmp(s, prefix, strlen(prefix)) != 0)
+        return NULL;
+    result = strchr(s, ':');
+    if (!result)
+        return NULL;
+    result++;
+    while (*result && (*result == ' ' || *result == '\t'))
+        result++;
+    return result;
+}
+
+static int is_space_or_eol(char x)
+{
+    return (x == 0 || x == ' ' || x == '\t' || x == '\n');
+}
+
+static int find_feature(const char *buffer, const char *feature)
+{
+    const char *s = buffer;
+    while (*s) {
+        char *t = strstr(s, feature);
+        if (!t)
+            return 0;
+        if (!is_space_or_eol(*(t + strlen(feature)))) {
+            s++;
+            continue;
+        }
+        if (t == buffer)
+            return 1;
+        if (t > buffer && is_space_or_eol(*(t - 1)))
+            return 1;
+        s++;
+    }
+    return 0;
+}
+
+static int parse_proc_cpuinfo(cpuinfo_t *cpuinfo)
+{
+    char *buffer = (char *)malloc(MAXBUFSIZE);
+    FILE *fd;
+    const char *val;
+
+    if (!buffer)
+        return 0;
+
+    fd = fopen("/proc/cpuinfo", "r");
+    if (!fd) {
+        free(buffer);
+        return 0;
+    }
+
+    while (fgets(buffer, MAXBUFSIZE, fd)) {
+        if (!strchr(buffer, '\n') && !feof(fd)) {
+            fclose(fd);
+            free(buffer);
+            return 0;
+        }
+        if ((val = cpuinfo_match_prefix(buffer, "Features"))) {
+            cpuinfo->has_arm_edsp = find_feature(val, "edsp");
+            cpuinfo->has_arm_vfp  = find_feature(val, "vfp");
+            cpuinfo->has_arm_neon = find_feature(val, "neon");
+        }
+        else if ((val = cpuinfo_match_prefix(buffer, "CPU implementer"))) {
+            if (sscanf(val, "%i", &cpuinfo->arm_implementer) != 1) {
+                fclose(fd);
+                free(buffer);
+                return 0;
+            }
+        }
+        else if ((val = cpuinfo_match_prefix(buffer, "CPU architecture"))) {
+            if (sscanf(val, "%i", &cpuinfo->arm_architecture) != 1) {
+                fclose(fd);
+                free(buffer);
+                return 0;
+            }
+        }
+        else if ((val = cpuinfo_match_prefix(buffer, "CPU variant"))) {
+            if (sscanf(val, "%i", &cpuinfo->arm_variant) != 1) {
+                fclose(fd);
+                free(buffer);
+                return 0;
+            }
+        }
+        else if ((val = cpuinfo_match_prefix(buffer, "CPU part"))) {
+            if (sscanf(val, "%i", &cpuinfo->arm_part) != 1) {
+                fclose(fd);
+                free(buffer);
+                return 0;
+            }
+        }
+        else if ((val = cpuinfo_match_prefix(buffer, "CPU revision"))) {
+            if (sscanf(val, "%x", &cpuinfo->arm_revision) != 1) {
+                fclose(fd);
+                free(buffer);
+                return 0;
+            }
+        }
+    }
+    fclose(fd);
+    free(buffer);
+    return 1;
+}
+
+#else
+
+static int parse_proc_cpuinfo(cpuinfo_t *cpuinfo)
+{
+    return 0;
+}
+
+#endif
+
+cpuinfo_t *cpuinfo_init()
+{
+    cpuinfo_t *cpuinfo = calloc(sizeof(cpuinfo_t), 1);
+    if (!cpuinfo)
+        return NULL;
+
+    if (!parse_proc_cpuinfo(cpuinfo)) {
+        cpuinfo->processor_name = strdup("Unknown");
+        return cpuinfo;
+    }
+
+    if (cpuinfo->arm_implementer == 0x41 && cpuinfo->arm_part == 0xC0F) {
+        cpuinfo->processor_name = strdup("ARM Cortex-A15");
+    } else if (cpuinfo->arm_implementer == 0x41 && cpuinfo->arm_part == 0xC09) {
+        if (cpuinfo->has_arm_neon)
+            cpuinfo->processor_name = strdup("ARM Cortex-A9");
+        else
+            cpuinfo->processor_name = strdup("ARM Cortex-A9 without NEON (Tegra2?)");
+    } else if (cpuinfo->arm_implementer == 0x41 && cpuinfo->arm_part == 0xC08) {
+        if (cpuinfo->arm_variant > 1)
+            cpuinfo->processor_name = strdup("Late ARM Cortex-A8 (NEON can bypass L1 cache)");
+        else
+            cpuinfo->processor_name = strdup("Early ARM Cortex-A8");
+    } else if (cpuinfo->arm_implementer == 0x41 && cpuinfo->arm_part == 0xC07) {
+        cpuinfo->processor_name = strdup("ARM Cortex-A7");
+    } else if (cpuinfo->arm_implementer == 0x41 && cpuinfo->arm_part == 0xC05) {
+        cpuinfo->processor_name = strdup("ARM Cortex-A5");
+    } else if (cpuinfo->arm_implementer == 0x41 && cpuinfo->arm_part == 0xB76) {
+        cpuinfo->processor_name = strdup("ARM1176");
+    } else {
+        cpuinfo->processor_name = strdup("Unknown");
+    }
+
+    return cpuinfo;
+}
+
+void cpuinfo_close(cpuinfo_t *cpuinfo)
+{
+    free(cpuinfo->processor_name);
+    free(cpuinfo);
+}
+
+int main()
+{
+    cpuinfo_t *cpuinfo = cpuinfo_init();
+    printf("%s %d\n", cpuinfo->processor_name, cpuinfo->has_arm_neon);
+    return 0;
+}

src/cpuinfo.h

+/*
+ * Copyright © 2013 Siarhei Siamashka <siarhei.siamashka@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef CPUINFO_H
+#define CPUINFO_H
+
+/* The information about CPU features */
+typedef struct {
+    /* The values originating from MIDR register */
+    int arm_implementer;
+    int arm_architecture;
+    int arm_variant;
+    int arm_part;
+    int arm_revision;
+    /* CPU features */
+    int has_arm_edsp;
+    int has_arm_vfp;
+    int has_arm_neon;
+    /* The user-friendly CPU description string (usable for logs, etc.) */
+    char *processor_name;
+} cpuinfo_t;
+
+cpuinfo_t *cpuinfo_init();
+void cpuinfo_close(cpuinfo_t *cpuinfo);
+
+#endif