metag: Add JTAG Debug Adapter (DA) support

Add basic JTAG Debug Adapter (DA) support so that drivers which
communicate with the DA can detect whether one is actually present
(otherwise the target will halt indefinitely).

This allows the metag_da TTY driver and imgdafs filesystem driver to be
built, updates defconfigs, and sets up the metag_da console early if
it's configured in.

Signed-off-by: James Hogan <james.hogan@imgtec.com>

1 files changed, 43 insertions, 0 deletions

diff --git a/arch/metag/include/asm/da.h b/arch/metag/include/asm/da.h
new file mode 100644
index 000000000000..81bd5212fb03
--- /dev/null
+++ b/arch/metag/include/asm/da.h
@@ -0,0 +1,43 @@
+/*
+ * Meta DA JTAG debugger control.
+ *
+ * Copyright 2012 Imagination Technologies Ltd.
+ */
+
+#ifndef _METAG_DA_H_
+#define _METAG_DA_H_
+
+#ifdef CONFIG_METAG_DA
+
+#include <linux/init.h>
+#include <linux/types.h>
+
+extern bool _metag_da_present;
+
+/**
+ * metag_da_enabled() - Find whether a DA is currently enabled.
+ *
+ * Returns:	true if a DA was detected, false if not.
+ */
+static inline bool metag_da_enabled(void)
+{
+	return _metag_da_present;
+}
+
+/**
+ * metag_da_probe() - Try and detect a connected DA.
+ *
+ * This is used at start up to detect whether a DA is active.
+ *
+ * Returns:	0 on detection, -err otherwise.
+ */
+int __init metag_da_probe(void);
+
+#else /* !CONFIG_METAG_DA */
+
+#define metag_da_enabled() false
+#define metag_da_probe() do {} while (0)
+
+#endif
+
+#endif /* _METAG_DA_H_ */