xtensa: hostfs: handle nonblock open for iss

Signed-off-by: chenxiaoyi <chenxiaoyi@xiaomi.com>

arch/xtensa/Kconfig

@@ -279,6 +279,14 @@ config XTENSA_SEMIHOSTING_HOSTFS
 		This doesn't support some directory operations like readdir because
 		of the limitations of semihosting mechanism.
 
+config XTENSA_TARGET_ISS
+	bool "Target machine is Instruction Set Simulator"
+	default n
+	---help---
+		This setting determines whether the target is Cadence Instruction
+		Set Simulator, which might have some sepecial characteristics such
+		as how to open a file nonblock.
+
 if XTENSA_SEMIHOSTING_HOSTFS
 
 config XTENSA_SEMIHOSTING_HOSTFS_CACHE_COHERENCE

arch/xtensa/include/simcall.h

@@ -63,6 +63,11 @@
 #define SIMCALL_O_RDWR     0x0002
 #define SIMCALL_O_ACCMODE  0x0003
 #define SIMCALL_O_APPEND   0x0400
+#ifdef CONFIG_XTENSA_TARGET_ISS
+#  define SIMCALL_O_NONBLOCK 0x0080
+#else
+#  define SIMCALL_O_NONBLOCK 0x0800
+#endif
 #define SIMCALL_O_CREAT    0x0040
 #define SIMCALL_O_TRUNC    0x0200
 #define SIMCALL_O_EXCL     0x0080

arch/xtensa/src/common/xtensa_hostfs.c

@@ -97,6 +97,11 @@ int host_open(const char *pathname, int flags, int mode)
       simcall_flags |= SIMCALL_O_EXCL;
     }
 
+  if ((flags & O_NONBLOCK) != 0)
+    {
+      simcall_flags |= SIMCALL_O_NONBLOCK;
+    }
+
 #ifdef CONFIG_XTENSA_SEMIHOSTING_HOSTFS_CACHE_COHERENCE
   up_clean_dcache(pathname, pathname + strlen(pathname) + 1);
 #endif