let nucleo (stm32l4) support proc fs for info useful for debug

configs/nucleo-l476rg/src/nucleo-l476rg.h

@@ -52,9 +52,19 @@
  ************************************************************************************/
 /* Configuration ********************************************************************/
 
+#define HAVE_PROC             1
 #define HAVE_RTC_DRIVER       1
 #define HAVE_MMCSD 1
 
+#if !defined(CONFIG_FS_PROCFS)
+#  undef HAVE_PROC
+#endif
+
+#if defined(HAVE_PROC) && defined(CONFIG_DISABLE_MOUNTPOINT)
+#  warning Mountpoints disabled.  No procfs support
+#  undef HAVE_PROC
+#endif
+
 /* Check if we can support the RTC driver */
 
 #if !defined(CONFIG_RTC) || !defined(CONFIG_RTC_DRIVER)

configs/nucleo-l476rg/src/stm32_appinit.c

@@ -39,7 +39,11 @@
 
 #include <nuttx/config.h>
 
+#include <sys/types.h>
+#include <sys/mount.h>
 #include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
 #include <syslog.h>
 #include <errno.h>
 
@@ -118,6 +122,21 @@ int board_app_initialize(uintptr_t arg)
   cpuload_initialize_once();
 #endif
 
+#ifdef HAVE_PROC
+  /* mount the proc filesystem */
+
+  syslog(LOG_INFO, "Mounting procfs to /proc\n");
+
+  ret = mount(NULL, CONFIG_NSH_PROC_MOUNTPOINT, "procfs", 0, NULL);
+  if (ret < 0)
+    {
+      syslog(LOG_ERR,
+             "ERROR: Failed to mount the PROC filesystem: %d (%d)\n",
+             ret, errno);
+      return ret;
+    }
+#endif
+
 #ifdef HAVE_RTC_DRIVER
   /* Instantiate the STM32L4 lower-half RTC driver */