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, 115 insertions, 0 deletions

diff --git a/src/ec/kontron/kempld/kempld.c b/src/ec/kontron/kempld/kempld.c
new file mode 100644
index 0000000000..19c18804c2
--- /dev/null
+++ b/src/ec/kontron/kempld/kempld.c
@@ -0,0 +1,115 @@
+/*
+ * 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 <console/console.h>
+#include <device/device.h>
+
+#include "chip.h"
+#include "kempld.h"
+#include "kempld_internal.h"
+
+static void kempld_uart_read_resources(struct device *dev)
+{
+	static const unsigned int io_addr[] = { 0x3f8, 0x2f8, 0x3e8, 0x2e8 };
+
+	const struct ec_kontron_kempld_config *const config = dev->chip_info;
+
+	struct resource *const res_io = new_resource(dev, 0);
+	struct resource *const res_irq = new_resource(dev, 1);
+	const unsigned int uart = dev->path.generic.subid;
+	if (!config || !res_io || !res_irq || uart >= KEMPLD_NUM_UARTS)
+		return;
+
+	const enum kempld_uart_io io = config->uart[uart].io;
+	if (io >= ARRAY_SIZE(io_addr)) {
+		printk(BIOS_ERR, "KEMPLD: Bad io value '%d' for UART#%u\n.",
+		       io, uart);
+		dev->enabled = false;
+		return;
+	}
+
+	const int irq = config->uart[uart].irq;
+	if (irq >= 16) {
+		printk(BIOS_ERR, "KEMPLD: Bad irq value '%d' for UART#%u\n.",
+		       irq, uart);
+		dev->enabled = false;
+		return;
+	}
+
+	res_io->base = io_addr[io];
+	res_io->size = 8;
+	res_io->flags = IORESOURCE_IO | IORESOURCE_FIXED |
+			IORESOURCE_STORED | IORESOURCE_ASSIGNED;
+	res_irq->base = irq;
+	res_irq->size = 1;
+	res_irq->flags = IORESOURCE_IO | IORESOURCE_FIXED |
+			 IORESOURCE_STORED | IORESOURCE_ASSIGNED;
+
+	if (kempld_get_mutex(100) < 0)
+		return;
+
+	const uint8_t reg = uart ? KEMPLD_UART_1 : KEMPLD_UART_0;
+	const uint8_t val = kempld_read8(reg);
+	kempld_write8(reg, (val & ~(KEMPLD_UART_IO_MASK | KEMPLD_UART_IRQ_MASK))
+			   | io << KEMPLD_UART_IO_SHIFT
+			   | irq << KEMPLD_UART_IRQ_SHIFT);
+
+	kempld_release_mutex();
+}
+
+static void kempld_uart_enable_resources(struct device *dev)
+{
+	if (kempld_get_mutex(100) < 0)
+		return;
+
+	const unsigned int uart = dev->path.generic.subid;
+	const uint8_t reg = uart ? KEMPLD_UART_1 : KEMPLD_UART_0;
+	kempld_write8(reg, kempld_read8(reg) | KEMPLD_UART_ENABLE);
+
+	kempld_release_mutex();
+}
+
+static struct device_operations kempld_uart_ops = {
+	.read_resources   = kempld_uart_read_resources,
+	.enable_resources = kempld_uart_enable_resources,
+};
+
+static void kempld_enable_dev(struct device *const dev)
+{
+	if (dev->path.type == DEVICE_PATH_GENERIC) {
+		switch (dev->path.generic.id) {
+		case 0:
+			if (dev->path.generic.subid < KEMPLD_NUM_UARTS) {
+				dev->ops = &kempld_uart_ops;
+				break;
+			}
+		case 1:
+			if (dev->path.generic.subid == 0) {
+				kempld_i2c_device_init(dev);
+				break;
+			}
+		default:
+			printk(BIOS_WARNING,
+			       "KEMPLD: Spurious device %s.\n",
+			       dev_path(dev));
+			break;
+		}
+	}
+}
+
+struct chip_operations ec_kontron_kempld_ops = {
+	CHIP_NAME("Kontron KEMPLD")
+	.enable_dev = kempld_enable_dev,
+};