[MIPS] Qemu: Add early printk, your friend in a cold night.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

4 files changed, 34 insertions, 4 deletions

diff --git a/arch/mips/qemu/Makefile b/arch/mips/qemu/Makefile
index cec24c117f6e..2ba4ef34b4a7 100644
--- a/arch/mips/qemu/Makefile
+++ b/arch/mips/qemu/Makefile
@@ -4,6 +4,7 @@
 
 obj-y           = q-firmware.o q-irq.o q-mem.o q-setup.o q-reset.o
 
-obj-$(CONFIG_SMP) += q-smp.o
+obj-$(CONFIG_EARLY_PRINTK)      += q-console.o
+obj-$(CONFIG_SMP)               += q-smp.o
 
 EXTRA_CFLAGS += -Werror
diff --git a/arch/mips/qemu/q-console.c b/arch/mips/qemu/q-console.c
new file mode 100644
index 000000000000..81101ae5017a
--- /dev/null
+++ b/arch/mips/qemu/q-console.c
@@ -0,0 +1,26 @@
+#include <linux/console.h>
+#include <linux/init.h>
+#include <linux/serial_reg.h>
+#include <asm/io.h>
+
+#define PORT(offset) (0x3f8 + (offset))
+
+static inline unsigned int serial_in(int offset)
+{
+        return inb(PORT(offset));
+}
+
+static inline void serial_out(int offset, int value)
+{
+        outb(value, PORT(offset));
+}
+
+int prom_putchar(char c)
+{
+        while ((serial_in(UART_LSR) & UART_LSR_THRE) == 0)
+                ;
+
+        serial_out(UART_TX, c);
+
+        return 1;
+}
diff --git a/arch/mips/qemu/q-firmware.c b/arch/mips/qemu/q-firmware.c
index c2239b417587..3ed43f416cd1 100644
--- a/arch/mips/qemu/q-firmware.c
+++ b/arch/mips/qemu/q-firmware.c
@@ -2,6 +2,9 @@
 #include <linux/string.h>
 #include <asm/addrspace.h>
 #include <asm/bootinfo.h>
+#include <asm/io.h>
+
+#define QEMU_PORT_BASE 0xb4000000
 
 void __init prom_init(void)
 {
@@ -15,4 +18,7 @@ void __init prom_init(void)
         } else {
                 add_memory_region(0x0<<20, 0x10<<20, BOOT_MEM_RAM);
         }
+
+
+        set_io_port_base(QEMU_PORT_BASE);
 }
diff --git a/arch/mips/qemu/q-setup.c b/arch/mips/qemu/q-setup.c
index 23d34c1917c0..969cedc8d8b9 100644
--- a/arch/mips/qemu/q-setup.c
+++ b/arch/mips/qemu/q-setup.c
@@ -6,8 +6,6 @@
 
 extern void qemu_reboot_setup(void);
 
-#define QEMU_PORT_BASE 0xb4000000
-
 const char *get_system_type(void)
 {
         return "Qemu";
@@ -20,6 +18,5 @@ void __init plat_time_init(void)
 
 void __init plat_mem_setup(void)
 {
-        set_io_port_base(QEMU_PORT_BASE);
         qemu_reboot_setup();
 }