MIPS: add support for SGI Octane (IP30)

This changeset adds support for SGI Octane/Octane2 workstations.

Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
diff --git a/arch/mips/sgi-ip30/ip30-console.c b/arch/mips/sgi-ip30/ip30-console.c
new file mode 100644
index 0000000..b91f8c4
--- /dev/null
+++ b/arch/mips/sgi-ip30/ip30-console.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/io.h>
+
+#include <asm/sn/ioc3.h>
+
+static inline struct ioc3_uartregs *console_uart(void)
+{
+	struct ioc3 *ioc3;
+
+	ioc3 = (struct ioc3 *)((void *)(0x900000001f600000));
+	return &ioc3->sregs.uarta;
+}
+
+void prom_putchar(char c)
+{
+	struct ioc3_uartregs *uart = console_uart();
+
+	while ((readb(&uart->iu_lsr) & 0x20) == 0)
+		cpu_relax();
+
+	writeb(c, &uart->iu_thr);
+}