MIPS, ttyFDC: Add early FDC console support

Add support for early console of MIPS Fast Debug Channel (FDC) on
channel 1 with a call very early from the MIPS setup_arch().

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/9145/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/arch/mips/include/asm/cdmm.h b/arch/mips/include/asm/cdmm.h
index b7d520f28d30..16e22ce9719f 100644
--- a/arch/mips/include/asm/cdmm.h
+++ b/arch/mips/include/asm/cdmm.h
@@ -84,4 +84,15 @@ void mips_cdmm_driver_unregister(struct mips_cdmm_driver *);
         module_driver(__mips_cdmm_driver, mips_cdmm_driver_register, \
                         mips_cdmm_driver_unregister)
 
+/* drivers/tty/mips_ejtag_fdc.c */
+
+#ifdef CONFIG_MIPS_EJTAG_FDC_EARLYCON
+int setup_early_fdc_console(void);
+#else
+static inline int setup_early_fdc_console(void)
+{
+        return -ENODEV;
+}
+#endif
+
 #endif /* __ASM_CDMM_H */