console: Add SimNow console logging

The AMD SimNow tool supports fast logging through an IO port.  Add a new
console to support SimNow logging through port 80.

TEST=observe significant speed improvements on SimNow console log

Signed-off-by: Fred Reitberger <reitbergerfred@gmail.com>
Change-Id: I42a431f48ea14ba4adacbd4a32e15abe7c5e4951
Reviewed-on: https://review.coreboot.org/c/coreboot/+/72751
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/soc/amd/common/block/simnow/Makefile.inc

@@ -0,0 +1,7 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
+ifeq ($(CONFIG_CONSOLE_AMD_SIMNOW),y)
+all-y += simnow_console.c
+
+smm-$(CONFIG_DEBUG_SMI) += simnow_console.c
+endif

src/soc/amd/common/block/simnow/simnow_console.c

@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <arch/io.h>
+#include <console/console.h>
+#include <console/simnow.h>
+
+#define AMD_SIMNOW_PORT			0x80
+#define AMD_SIMNOW_PORT_DATA_BEGIN	0x5f535452ul
+#define AMD_SIMNOW_PORT_DATA_END	0x5f454e44ul
+
+void simnow_console_init(void)
+{
+	outl(AMD_SIMNOW_PORT_DATA_BEGIN, AMD_SIMNOW_PORT);
+}
+
+void simnow_console_tx_byte(unsigned char data)
+{
+	outb(data, AMD_SIMNOW_PORT);
+
+	if (data == '\n') {
+		outl(AMD_SIMNOW_PORT_DATA_END, AMD_SIMNOW_PORT);
+		outl(AMD_SIMNOW_PORT_DATA_BEGIN, AMD_SIMNOW_PORT);
+	}
+}