Doxygen file comments

Add file comments to a few files.  Make the GDB server use
more conventional (pointer-free) hex digit conversion.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

src/flash/nor/core.c

@@ -29,6 +29,13 @@
 #include <target/image.h>
 
 
+/**
+ * @file
+ * Upper level of NOR flash framework.
+ * The lower level interfaces are to drivers.  These upper level ones
+ * primarily support access from Tcl scripts or from GDB.
+ */
+
 struct flash_bank *flash_banks;
 
 int flash_driver_erase(struct flash_bank *bank, int first, int last)

src/flash/nor/core.h

@@ -24,6 +24,11 @@
 
 #include <flash/common.h>
 
+/**
+ * @file
+ * Upper level NOR flash interfaces.
+ */
+
 struct image;
 
 #define FLASH_MAX_ERROR_STR	(128)

src/flash/nor/tcl.c

@@ -26,6 +26,11 @@
 #include <helper/time_support.h>
 #include <target/image.h>
 
+/**
+ * @file
+ * Implements Tcl commands used to access NOR flash facilities.
+ */
+
 COMMAND_HELPER(flash_command_get_bank, unsigned name_index,
 		struct flash_bank **bank)
 {

src/server/gdb_server.c

@@ -37,6 +37,15 @@
 #include <jtag/jtag.h>
 
 
+/**
+ * @file
+ * GDB server implementation.
+ *
+ * This implements the GDB Remote Serial Protocol, over TCP connections,
+ * giving GDB access to the JTAG or other hardware debugging facilities
+ * found in most modern embedded processors.
+ */
+
 /* private connection data for GDB */
 struct gdb_connection
 {
@@ -68,7 +77,7 @@ static enum breakpoint_type gdb_breakpoint_override_type;
 extern int gdb_error(struct connection *connection, int retval);
 static unsigned short gdb_port = 3333;
 static unsigned short gdb_port_next = 0;
-static const char *DIGITS = "0123456789abcdef";
+static const char DIGITS[16] = "0123456789abcdef";
 
 static void gdb_log_callback(void *priv, const char *file, unsigned line,
 		const char *function, const char *string);