sandbox: Improve sandbox serial port keyboard interface
Implements the tstc() interface for the serial driver. Multiplexing
the console between the serial port and a keyboard uses a polling
method of checking if characters are available; this means that the
serial console must be non-blocking when attempting to read
characters.
Signed-off-by: Taylor Hutt <thutt@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/os.h b/include/os.h
index 699682a..c452d1b 100644
--- a/include/os.h
+++ b/include/os.h
@@ -40,6 +40,16 @@
ssize_t os_read(int fd, void *buf, size_t count);
/**
+ * Access to the OS read() system call with non-blocking access
+ *
+ * \param fd File descriptor as returned by os_open()
+ * \param buf Buffer to place data
+ * \param count Number of bytes to read
+ * \return number of bytes read, or -1 on error
+ */
+ssize_t os_read_no_block(int fd, void *buf, size_t count);
+
+/**
* Access to the OS write() system call
*
* \param fd File descriptor as returned by os_open()