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/*
* 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");
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