1 files changed, 109 insertions, 0 deletions
diff --git a/drivers/firmware/google/memconsole-coreboot.c b/drivers/firmware/google/memconsole-coreboot.c
new file mode 100644
index 000000000000..02711114dece
--- /dev/null
+++ b/drivers/firmware/google/memconsole-coreboot.c
@@ -0,0 +1,109 @@
+/*
+ * memconsole-coreboot.c
+ *
+ * Memory based BIOS console accessed through coreboot table.
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include "memconsole.h"
+#include "coreboot_table.h"
+
+#define CB_TAG_CBMEM_CONSOLE	0x17
+
+/* CBMEM firmware console log descriptor. */
+struct cbmem_cons {
+	u32 buffer_size;
+	u32 buffer_cursor;
+	u8  buffer_body[0];
+} __packed;
+
+static struct cbmem_cons __iomem *cbmem_console;
+
+static int memconsole_coreboot_init(phys_addr_t physaddr)
+{
+	struct cbmem_cons __iomem *tmp_cbmc;
+
+	tmp_cbmc = memremap(physaddr, sizeof(*tmp_cbmc), MEMREMAP_WB);
+
+	if (!tmp_cbmc)
+		return -ENOMEM;
+
+	cbmem_console = memremap(physaddr,
+				 tmp_cbmc->buffer_size + sizeof(*cbmem_console),
+				 MEMREMAP_WB);
+	memunmap(tmp_cbmc);
+
+	if (!cbmem_console)
+		return -ENOMEM;
+
+	memconsole_setup(cbmem_console->buffer_body,
+		min(cbmem_console->buffer_cursor, cbmem_console->buffer_size));
+
+	return 0;
+}
+
+static int memconsole_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct lb_cbmem_ref entry;
+
+	ret = coreboot_table_find(CB_TAG_CBMEM_CONSOLE, &entry, sizeof(entry));
+	if (ret)
+		return ret;
+
+	ret = memconsole_coreboot_init(entry.cbmem_addr);
+	if (ret)
+		return ret;
+
+	return memconsole_sysfs_init();
+}
+
+static int memconsole_remove(struct platform_device *pdev)
+{
+	memconsole_exit();
+
+	if (cbmem_console)
+		memunmap(cbmem_console);
+
+	return 0;
+}
+
+static struct platform_driver memconsole_driver = {
+	.probe = memconsole_probe,
+	.remove = memconsole_remove,
+	.driver = {
+		.name = "memconsole",
+	},
+};
+
+static int __init platform_memconsole_init(void)
+{
+	struct platform_device *pdev;
+
+	pdev = platform_device_register_simple("memconsole", -1, NULL, 0);
+	if (IS_ERR(pdev))
+		return PTR_ERR(pdev);
+
+	platform_driver_register(&memconsole_driver);
+
+	return 0;
+}
+
+module_init(platform_memconsole_init);
+
+MODULE_AUTHOR("Google, Inc.");
+MODULE_LICENSE("GPL");