MIPS: zboot: Add support for serial debug using the PROM

AlbanBedel · ralfbaechle · commit dbb983145312 · 2016-01-24T04:05:51.000+01:00
As most platforms implement the PROM serial interface prom_putchar() add a simple bridge to allow re-using this code for zboot. Signed-off-by: Alban Bedel <albeu@free.fr> Cc: Alex Smith <alex.smith@imgtec.com> Cc: Andrew Bresticker <abrestic@chromium.org> Cc: Wu Zhangjin <wuzhangjin@gmail.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/11811/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
@@ -1766,6 +1766,10 @@ config SYS_SUPPORTS_ZBOOT_UART16550
 	bool
 	select SYS_SUPPORTS_ZBOOT
 
+config SYS_SUPPORTS_ZBOOT_UART_PROM
+	bool
+	select SYS_SUPPORTS_ZBOOT
+
 config CPU_LOONGSON2
 	bool
 	select CPU_SUPPORTS_32BIT_KERNEL
diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
@@ -35,6 +35,7 @@ vmlinuzobjs-y := $(obj)/head.o $(obj)/decompress.o $(obj)/string.o
 ifdef CONFIG_DEBUG_ZBOOT
 vmlinuzobjs-$(CONFIG_DEBUG_ZBOOT)		   += $(obj)/dbg.o
 vmlinuzobjs-$(CONFIG_SYS_SUPPORTS_ZBOOT_UART16550) += $(obj)/uart-16550.o
+vmlinuzobjs-$(CONFIG_SYS_SUPPORTS_ZBOOT_UART_PROM) += $(obj)/uart-prom.o
 vmlinuzobjs-$(CONFIG_MIPS_ALCHEMY)		   += $(obj)/uart-alchemy.o
 endif
 
diff --git a/arch/mips/boot/compressed/uart-prom.c b/arch/mips/boot/compressed/uart-prom.c
@@ -0,0 +1,7 @@
+
+extern void prom_putchar(unsigned char ch);
+
+void putc(char c)
+{
+	prom_putchar(c);
+}
