1 files changed, 21 insertions, 133 deletions

diff --git a/drivers/firmware/google/memconsole.c b/drivers/firmware/google/memconsole.c
index 2a90ba613613..6138a1653ec5 100644
--- a/drivers/firmware/google/memconsole.c
+++ b/drivers/firmware/google/memconsole.c
@@ -1,55 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * memconsole.c
  *
- * Infrastructure for importing the BIOS memory based console
- * into the kernel log ringbuffer.
+ * Architecture-independent parts of the memory based BIOS console.
  *
- * Copyright 2010 Google Inc. All rights reserved.
+ * Copyright 2017 Google Inc.
  */
 
-#include <linux/ctype.h>
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/string.h>
 #include <linux/sysfs.h>
 #include <linux/kobject.h>
 #include <linux/module.h>
-#include <linux/dmi.h>
-#include <asm/bios_ebda.h>
 
-#define BIOS_MEMCONSOLE_V1_MAGIC	0xDEADBABE
-#define BIOS_MEMCONSOLE_V2_MAGIC	(('M')|('C'<<8)|('O'<<16)|('N'<<24))
-
-struct biosmemcon_ebda {
-	u32 signature;
-	union {
-		struct {
-			u8  enabled;
-			u32 buffer_addr;
-			u16 start;
-			u16 end;
-			u16 num_chars;
-			u8  wrapped;
-		} __packed v1;
-		struct {
-			u32 buffer_addr;
-			/* Misdocumented as number of pages! */
-			u16 num_bytes;
-			u16 start;
-			u16 end;
-		} __packed v2;
-	};
-} __packed;
-
-static char *memconsole_baseaddr;
-static size_t memconsole_length;
+#include "memconsole.h"
 
 static ssize_t memconsole_read(struct file *filp, struct kobject *kobp,
-			       struct bin_attribute *bin_attr, char *buf,
+			       const struct bin_attribute *bin_attr, char *buf,
 			       loff_t pos, size_t count)
 {
-	return memory_read_from_buffer(buf, count, &pos, memconsole_baseaddr,
-				       memconsole_length);
+	ssize_t (*memconsole_read_func)(char *, loff_t, size_t);
+
+	memconsole_read_func = bin_attr->private;
+	if (WARN_ON_ONCE(!memconsole_read_func))
+		return -EIO;
+
+	return memconsole_read_func(buf, pos, count);
 }
 
 static struct bin_attribute memconsole_bin_attr = {
@@ -57,110 +31,24 @@ static struct bin_attribute memconsole_bin_attr = {
 	.read = memconsole_read,
 };
 
-
-static void found_v1_header(struct biosmemcon_ebda *hdr)
+void memconsole_setup(ssize_t (*read_func)(char *, loff_t, size_t))
 {
-	printk(KERN_INFO "BIOS console v1 EBDA structure found at %p\n", hdr);
-	printk(KERN_INFO "BIOS console buffer at 0x%.8x, "
-	       "start = %d, end = %d, num = %d\n",
-	       hdr->v1.buffer_addr, hdr->v1.start,
-	       hdr->v1.end, hdr->v1.num_chars);
-
-	memconsole_length = hdr->v1.num_chars;
-	memconsole_baseaddr = phys_to_virt(hdr->v1.buffer_addr);
+	memconsole_bin_attr.private = read_func;
 }
+EXPORT_SYMBOL(memconsole_setup);
 
-static void found_v2_header(struct biosmemcon_ebda *hdr)
+int memconsole_sysfs_init(void)
 {
-	printk(KERN_INFO "BIOS console v2 EBDA structure found at %p\n", hdr);
-	printk(KERN_INFO "BIOS console buffer at 0x%.8x, "
-	       "start = %d, end = %d, num_bytes = %d\n",
-	       hdr->v2.buffer_addr, hdr->v2.start,
-	       hdr->v2.end, hdr->v2.num_bytes);
-
-	memconsole_length = hdr->v2.end - hdr->v2.start;
-	memconsole_baseaddr = phys_to_virt(hdr->v2.buffer_addr
-					   + hdr->v2.start);
+	return sysfs_create_bin_file(firmware_kobj, &memconsole_bin_attr);
 }
+EXPORT_SYMBOL(memconsole_sysfs_init);
 
-/*
- * Search through the EBDA for the BIOS Memory Console, and
- * set the global variables to point to it.  Return true if found.
- */
-static bool found_memconsole(void)
-{
-	unsigned int address;
-	size_t length, cur;
-
-	address = get_bios_ebda();
-	if (!address) {
-		printk(KERN_INFO "BIOS EBDA non-existent.\n");
-		return false;
-	}
-
-	/* EBDA length is byte 0 of EBDA (in KB) */
-	length = *(u8 *)phys_to_virt(address);
-	length <<= 10; /* convert to bytes */
-
-	/*
-	 * Search through EBDA for BIOS memory console structure
-	 * note: signature is not necessarily dword-aligned
-	 */
-	for (cur = 0; cur < length; cur++) {
-		struct biosmemcon_ebda *hdr = phys_to_virt(address + cur);
-
-		/* memconsole v1 */
-		if (hdr->signature == BIOS_MEMCONSOLE_V1_MAGIC) {
-			found_v1_header(hdr);
-			return true;
-		}
-
-		/* memconsole v2 */
-		if (hdr->signature == BIOS_MEMCONSOLE_V2_MAGIC) {
-			found_v2_header(hdr);
-			return true;
-		}
-	}
-
-	printk(KERN_INFO "BIOS console EBDA structure not found!\n");
-	return false;
-}
-
-static struct dmi_system_id memconsole_dmi_table[] __initdata = {
-	{
-		.ident = "Google Board",
-		.matches = {
-			DMI_MATCH(DMI_BOARD_VENDOR, "Google, Inc."),
-		},
-	},
-	{}
-};
-MODULE_DEVICE_TABLE(dmi, memconsole_dmi_table);
-
-static int __init memconsole_init(void)
-{
-	int ret;
-
-	if (!dmi_check_system(memconsole_dmi_table))
-		return -ENODEV;
-
-	if (!found_memconsole())
-		return -ENODEV;
-
-	memconsole_bin_attr.size = memconsole_length;
-
-	ret = sysfs_create_bin_file(firmware_kobj, &memconsole_bin_attr);
-
-	return ret;
-}
-
-static void __exit memconsole_exit(void)
+void memconsole_exit(void)
 {
 	sysfs_remove_bin_file(firmware_kobj, &memconsole_bin_attr);
 }
-
-module_init(memconsole_init);
-module_exit(memconsole_exit);
+EXPORT_SYMBOL(memconsole_exit);
 
 MODULE_AUTHOR("Google, Inc.");
+MODULE_DESCRIPTION("Architecture-independent parts of the memory based BIOS console");
 MODULE_LICENSE("GPL");