[v0.11] Fetch and print max Intel iGPU frequency using sysfs

src/intel/udev.cpp

@@ -0,0 +1,89 @@
+#include <cstddef>
+#include <cstring>
+#include <cstdlib>
+#include <cstdint>
+#include <cerrno>
+#include <cstdio>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "../common/global.hpp"
+#include "../common/pci.hpp"
+
+#define _PATH_SYS_SYSTEM        "/sys/devices/pci0000:00"
+#define _PATH_SYS_DRM           "/drm"
+#define _PATH_CARD              "/card0"
+#define _PATH_FREQUENCY_MAX     "/gt_max_freq_mhz"
+#define _PATH_FREQUENCY_MIN     "/gt_min_freq_mhz"
+
+#define _PATH_FREQUENCY_MAX_LEN 100
+#define DEFAULT_FILE_SIZE       4096
+#define UNKNOWN_DATA            -1
+
+char* read_file(char* path, int* len) {
+  int fd = open(path, O_RDONLY);
+
+  if(fd == -1) {
+    return NULL;
+  }
+
+  //File exists, read it
+  int bytes_read = 0;
+  int offset = 0;
+  int block = 128;
+  char* buf = (char *) emalloc(sizeof(char)*DEFAULT_FILE_SIZE);
+  memset(buf, 0, sizeof(char)*DEFAULT_FILE_SIZE);
+
+  while (  (bytes_read = read(fd, buf+offset, block)) > 0 ) {
+    offset += bytes_read;
+  }
+
+  if (close(fd) == -1) {
+    return NULL;
+  }
+
+  *len = offset;
+  return buf;
+}
+
+long get_freq_from_file(char* path) {
+  int filelen;
+  char* buf;
+  if((buf = read_file(path, &filelen)) == NULL) {
+    printWarn("Could not open '%s'", path);
+    return UNKNOWN_DATA;
+  }
+
+  char* end;
+  errno = 0;
+  long ret = strtol(buf, &end, 10);
+  if(errno != 0) {
+    printBug("strtol: %s", strerror(errno));
+    free(buf);
+    return UNKNOWN_DATA;
+  }
+
+  // We will be getting the frequency in MHz
+  // We consider it is an error if frequency is
+  // greater than 10 GHz or less than 100 MHz
+  if(ret > 10000 || ret <  100) {
+    printBug("Invalid data was read from file '%s': %ld\n", path, ret);
+    return UNKNOWN_DATA;
+  }
+
+  free(buf);
+
+  return ret;
+}
+
+long get_max_freq_from_file(struct pci* pci) {
+  char path[_PATH_FREQUENCY_MAX_LEN];
+  sprintf(path, "%s/%04x:%02x:%02x.%d%s%s%s", _PATH_SYS_SYSTEM, pci->domain, pci->bus, pci->dev, pci->func, _PATH_SYS_DRM, _PATH_CARD, _PATH_FREQUENCY_MAX);
+  return get_freq_from_file(path);
+}
+
+long get_min_freq_from_file(struct pci* pci) {
+  char path[_PATH_FREQUENCY_MAX_LEN];
+  sprintf(path, "%s/%04x:%02x:%02x.%d%s%s%s", _PATH_SYS_SYSTEM, pci->domain, pci->bus, pci->dev, pci->func, _PATH_SYS_DRM, _PATH_CARD, _PATH_FREQUENCY_MIN);
+  return get_freq_from_file(path);
+}