Add rsmi_dev_drm_render_minor_get()

Function to get the drm minor number associated with ROCm device

Change-Id: I9356b9ca75151882acbb075076bc072f08b73aae
Signed-off-by: Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>

include/rocm_smi/rocm_smi.h

@@ -830,6 +830,25 @@ rsmi_status_t rsmi_dev_subsystem_id_get(uint32_t dv_ind, uint16_t *id);
 rsmi_status_t
 rsmi_dev_subsystem_name_get(uint32_t dv_ind, char *name, size_t len);
 
+/**
+ *  @brief Get the drm minor number associated with this device
+ *
+ *  @details Given a device index @p dv_ind, find its render device file
+ *  /dev/dri/renderDN where N corresponds to its minor number.
+ *
+ *  @param[in] dv_ind a device index
+ *
+ *  @param[inout] minor a pointer to a uint32_t into which minor number will
+ *  be copied
+ *
+ *  @retval :: RSMI_STATUS_SUCCESS is returned upon successful call.
+ *  @retval :: RSMI_STATUS_INIT_ERROR if failed to get minor number during
+ *  initialization.
+ *
+ */
+rsmi_status_t
+rsmi_dev_drm_render_minor_get(uint32_t dv_ind, uint32_t *minor);
+
 /**
  *  @brief Get the device subsystem vendor id associated with the device with
  *  provided device index.

include/rocm_smi/rocm_smi_device.h

@@ -139,6 +139,8 @@ class Device {
     int writeDevInfo(DevInfoTypes type, std::string val);
     uint32_t index(void) const {return index_;}
     void set_index(uint32_t index) {index_ = index;}
+    uint32_t drm_render_minor(void) const {return drm_render_minor_;}
+    void set_drm_render_minor(uint32_t minor) {drm_render_minor_ = minor;}
     static rsmi_dev_perf_level perfLvlStrToEnum(std::string s);
     uint64_t bdfid(void) const {return bdfid_;}
     void set_bdfid(uint64_t val) {bdfid_ = val;}
@@ -153,6 +155,7 @@ class Device {
     std::string path_;
     shared_mutex_t mutex_;
     uint32_t index_;
+    uint32_t drm_render_minor_;
     const RocmSMI_env_vars *env_;
     template <typename T> int openSysfsFileStream(DevInfoTypes type, T *fs,
                                                    const char *str = nullptr);

src/rocm_smi.cc

@@ -1425,6 +1425,19 @@ static rsmi_status_t get_dev_name_from_id(uint32_t dv_ind, char *name,
 
   return RSMI_STATUS_SUCCESS;
 }
+
+static rsmi_status_t
+get_dev_drm_render_minor(uint32_t dv_ind, uint32_t *minor) {
+
+  GET_DEV_FROM_INDX
+
+  *minor = dev->drm_render_minor();
+  if (*minor)
+    return RSMI_STATUS_SUCCESS;
+
+  return RSMI_STATUS_INIT_ERROR;
+}
+
 rsmi_status_t
 rsmi_dev_name_get(uint32_t dv_ind, char *name, size_t len) {
   rsmi_status_t ret;
@@ -1458,6 +1471,20 @@ rsmi_dev_subsystem_name_get(uint32_t dv_ind, char *name, size_t len) {
   CATCH
 }
 
+rsmi_status_t
+rsmi_dev_drm_render_minor_get(uint32_t dv_ind, uint32_t *minor) {
+  rsmi_status_t ret;
+
+  TRY
+  if (minor == nullptr)
+    return RSMI_STATUS_INVALID_ARGS;
+
+  DEVICE_MUTEX
+  ret = get_dev_drm_render_minor(dv_ind, minor);
+  return ret;
+  CATCH
+}
+
 rsmi_status_t
 rsmi_dev_vendor_name_get(uint32_t dv_ind, char *name, size_t len) {
   rsmi_status_t ret;

src/rocm_smi_main.cc

@@ -82,6 +82,39 @@ static uint32_t GetDeviceIndex(const std::string s) {
   return stoi(t);
 }
 
+// Find the drm minor from from sysfs path "/sys/class/drm/cardX/device/drm".
+// From the directory renderDN in that sysfs path, the drm minor can be
+// computed for cardX.
+// On success, return drm_minor which is >= 128 otherwise return 0
+static uint32_t  GetDrmRenderMinor(const std::string s) {
+  std::string drm_path = s;
+  int drm_minor = 0;
+  const std::string render_file_prefix = "renderD";
+  const uint32_t prefix_size = render_file_prefix.size();
+  drm_path += "/device/drm";
+
+  auto drm_dir = opendir(drm_path.c_str());
+  if (drm_dir == nullptr)
+    return 0;
+
+  auto dentry = readdir(drm_dir);
+
+  while (dentry != nullptr) {
+    std::string render_file = dentry->d_name;
+    if (!render_file.compare(0, prefix_size, render_file_prefix)) {
+      drm_minor = stoi(render_file.substr(prefix_size));
+      if (drm_minor)
+        break;
+    }
+    dentry = readdir(drm_dir);
+  }
+
+  if (closedir(drm_dir))
+    return 0;
+
+  return drm_minor;
+}
+
 static int SameDevice(const std::string fileA, const std::string fileB) {
   return SameFile(fileA + "/device", fileB + "/device");
 }
@@ -300,6 +333,7 @@ RocmSMI::AddToDeviceList(std::string dev_name) {
 
   std::string d_name = dev_name;
   uint32_t d_index = GetDeviceIndex(d_name);
+  dev->set_drm_render_minor(GetDrmRenderMinor(dev_path));
   dev->set_index(d_index);
 
   GetSupportedEventGroups(d_index, dev->supported_event_groups());