ec/kontron: Add support for Kontron kempld

A programmable logic device used by Kontron as EC on their COM express
modules. The name `kempld` is taken from Linux kernel sources, as is the
I2C driver. The meaning of the acronym is unclear, probably: Kontron
Embedded Module PLD.

Change-Id: If9a0826c4a8f5c8cd573610c2d10561334258b36
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/c/29476
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

1 files changed, 72 insertions, 0 deletions

diff --git a/src/ec/kontron/kempld/early_kempld.c b/src/ec/kontron/kempld/early_kempld.c
new file mode 100644
index 0000000000..773b8b6ef9
--- /dev/null
+++ b/src/ec/kontron/kempld/early_kempld.c
@@ -0,0 +1,72 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2017 secunet Security Networks AG
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <stdint.h>
+#include <arch/io.h>
+#include <delay.h>
+
+#include "chip.h"
+#include "kempld.h"
+#include "kempld_internal.h"
+
+void kempld_write8(const uint8_t addr, const uint8_t data)
+{
+	outb(addr, KEMPLD_IDX);
+	outb(data, KEMPLD_DAT);
+}
+
+uint8_t kempld_read8(const uint8_t addr)
+{
+	outb(addr, KEMPLD_IDX);
+	return inb(KEMPLD_DAT);
+}
+
+int kempld_get_mutex(int timeout_ms)
+{
+	while (inb(KEMPLD_IDX) & KEMPLD_MUTEX_KEY && timeout_ms--)
+		mdelay(1);
+	return timeout_ms;
+}
+
+void kempld_release_mutex(void)
+{
+	outb(KEMPLD_MUTEX_KEY, KEMPLD_IDX);
+}
+
+void kempld_enable_uart_for_console(void)
+{
+	if (!IS_ENABLED(CONFIG_CONSOLE_SERIAL))
+		return;
+
+	if (kempld_get_mutex(100) < 0)
+		return;
+
+	switch (CONFIG_UART_FOR_CONSOLE) {
+	case 0:
+		kempld_write8(KEMPLD_UART_0,
+			      KEMPLD_UART_ENABLE |
+				KEMPLD_UART_3F8 << KEMPLD_UART_IO_SHIFT);
+		break;
+	case 1:
+		kempld_write8(KEMPLD_UART_1,
+			      KEMPLD_UART_ENABLE |
+				KEMPLD_UART_2F8 << KEMPLD_UART_IO_SHIFT);
+		break;
+	default:
+		break;
+	}
+
+	kempld_release_mutex();
+}