firmware: google memconsole: Add ARM/ARM64 support

This patch expands the Google firmware memory console driver to also
work on certain tree based platforms running coreboot, such as ARM/ARM64
Chromebooks. This patch now adds another path to find the coreboot table
through the device tree. In order to find that, a second level
bootloader must have installed the 'coreboot' compatible device tree
node that describes its base address and size.

This patch is a rework/split/merge of patches from the chromeos v4.4
kernel tree originally authored by:
 Wei-Ning Huang <wnhuang@chromium.org>
 Julius Werner <jwerner@chromium.org>
 Brian Norris <briannorris@chromium.org>

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 82 insertions, 0 deletions

diff --git a/drivers/firmware/google/coreboot_table-of.c b/drivers/firmware/google/coreboot_table-of.c
new file mode 100644
index 000000000000..727acdc83e83
--- /dev/null
+++ b/drivers/firmware/google/coreboot_table-of.c
@@ -0,0 +1,82 @@
+/*
+ * coreboot_table-of.c
+ *
+ * Coreboot table access through open firmware.
+ *
+ * Copyright 2017 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License v2.0 as published by
+ * the Free Software Foundation.
+ *
+ * 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 <linux/device.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+#include "coreboot_table.h"
+
+static int coreboot_table_of_probe(struct platform_device *pdev)
+{
+	struct device_node *fw_dn = pdev->dev.of_node;
+	void __iomem *ptr;
+
+	ptr = of_iomap(fw_dn, 0);
+	of_node_put(fw_dn);
+	if (!ptr)
+		return -ENOMEM;
+
+	return coreboot_table_init(ptr);
+}
+
+static int coreboot_table_of_remove(struct platform_device *pdev)
+{
+	return coreboot_table_exit();
+}
+
+static const struct of_device_id coreboot_of_match[] = {
+	{ .compatible = "coreboot" },
+	{},
+};
+
+static struct platform_driver coreboot_table_of_driver = {
+	.probe = coreboot_table_of_probe,
+	.remove = coreboot_table_of_remove,
+	.driver = {
+		.name = "coreboot_table_of",
+		.of_match_table = coreboot_of_match,
+	},
+};
+
+static int __init platform_coreboot_table_of_init(void)
+{
+	struct platform_device *pdev;
+	struct device_node *of_node;
+
+	/* Limit device creation to the presence of /firmware/coreboot node */
+	of_node = of_find_node_by_path("/firmware/coreboot");
+	if (!of_node)
+		return -ENODEV;
+
+	if (!of_match_node(coreboot_of_match, of_node))
+		return -ENODEV;
+
+	pdev = of_platform_device_create(of_node, "coreboot_table_of", NULL);
+	if (!pdev)
+		return -ENODEV;
+
+	return platform_driver_register(&coreboot_table_of_driver);
+}
+
+module_init(platform_coreboot_table_of_init);
+
+MODULE_AUTHOR("Google, Inc.");
+MODULE_LICENSE("GPL");