dell-laptop: extract SMBIOS-related code to a separate module

Extract SMBIOS-related code from dell-laptop to a new kernel module,
dell-smbios.  The static specifier is removed from exported symbols,
otherwise code is just moved around.

Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
[dvhart: Include linux/io.h in dell-smbios.c as caught by lkp]
Signed-off-by: Darren Hart <dvhart@linux.intel.com>

1 files changed, 194 insertions, 0 deletions

diff --git a/drivers/platform/x86/dell-smbios.c b/drivers/platform/x86/dell-smbios.c
new file mode 100644
index 000000000000..d1aae53dc7a7
--- /dev/null
+++ b/drivers/platform/x86/dell-smbios.c
@@ -0,0 +1,194 @@
+/*
+ *  Common functions for kernel modules using Dell SMBIOS
+ *
+ *  Copyright (c) Red Hat <mjg@redhat.com>
+ *  Copyright (c) 2014 Gabriele Mazzotta <gabriele.mzt@gmail.com>
+ *  Copyright (c) 2014 Pali Rohár <pali.rohar@gmail.com>
+ *
+ *  Based on documentation in the libsmbios package:
+ *  Copyright (C) 2005-2014 Dell Inc.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/dmi.h>
+#include <linux/gfp.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include "../../firmware/dcdbas.h"
+#include "dell-smbios.h"
+
+struct calling_interface_structure {
+	struct dmi_header header;
+	u16 cmdIOAddress;
+	u8 cmdIOCode;
+	u32 supportedCmds;
+	struct calling_interface_token tokens[];
+} __packed;
+
+struct calling_interface_buffer *buffer;
+EXPORT_SYMBOL_GPL(buffer);
+static DEFINE_MUTEX(buffer_mutex);
+
+static int da_command_address;
+static int da_command_code;
+static int da_num_tokens;
+struct calling_interface_token *da_tokens;
+EXPORT_SYMBOL_GPL(da_tokens);
+
+void get_buffer(void)
+{
+	mutex_lock(&buffer_mutex);
+	clear_buffer();
+}
+EXPORT_SYMBOL_GPL(get_buffer);
+
+void clear_buffer(void)
+{
+	memset(buffer, 0, sizeof(struct calling_interface_buffer));
+}
+EXPORT_SYMBOL_GPL(clear_buffer);
+
+void release_buffer(void)
+{
+	mutex_unlock(&buffer_mutex);
+}
+EXPORT_SYMBOL_GPL(release_buffer);
+
+struct calling_interface_buffer *
+dell_send_request(struct calling_interface_buffer *buffer,
+		  int class, int select)
+{
+	struct smi_cmd command;
+
+	command.magic = SMI_CMD_MAGIC;
+	command.command_address = da_command_address;
+	command.command_code = da_command_code;
+	command.ebx = virt_to_phys(buffer);
+	command.ecx = 0x42534931;
+
+	buffer->class = class;
+	buffer->select = select;
+
+	dcdbas_smi_request(&command);
+
+	return buffer;
+}
+EXPORT_SYMBOL_GPL(dell_send_request);
+
+int find_token_id(int tokenid)
+{
+	int i;
+
+	for (i = 0; i < da_num_tokens; i++) {
+		if (da_tokens[i].tokenID == tokenid)
+			return i;
+	}
+
+	return -1;
+}
+EXPORT_SYMBOL_GPL(find_token_id);
+
+int find_token_location(int tokenid)
+{
+	int id;
+
+	id = find_token_id(tokenid);
+	if (id == -1)
+		return -1;
+
+	return da_tokens[id].location;
+}
+EXPORT_SYMBOL_GPL(find_token_location);
+
+static void __init parse_da_table(const struct dmi_header *dm)
+{
+	/* Final token is a terminator, so we don't want to copy it */
+	int tokens = (dm->length-11)/sizeof(struct calling_interface_token)-1;
+	struct calling_interface_token *new_da_tokens;
+	struct calling_interface_structure *table =
+		container_of(dm, struct calling_interface_structure, header);
+
+	/* 4 bytes of table header, plus 7 bytes of Dell header, plus at least
+	   6 bytes of entry */
+
+	if (dm->length < 17)
+		return;
+
+	da_command_address = table->cmdIOAddress;
+	da_command_code = table->cmdIOCode;
+
+	new_da_tokens = krealloc(da_tokens, (da_num_tokens + tokens) *
+				 sizeof(struct calling_interface_token),
+				 GFP_KERNEL);
+
+	if (!new_da_tokens)
+		return;
+	da_tokens = new_da_tokens;
+
+	memcpy(da_tokens+da_num_tokens, table->tokens,
+	       sizeof(struct calling_interface_token) * tokens);
+
+	da_num_tokens += tokens;
+}
+
+static void __init find_tokens(const struct dmi_header *dm, void *dummy)
+{
+	switch (dm->type) {
+	case 0xd4: /* Indexed IO */
+	case 0xd5: /* Protected Area Type 1 */
+	case 0xd6: /* Protected Area Type 2 */
+		break;
+	case 0xda: /* Calling interface */
+		parse_da_table(dm);
+		break;
+	}
+}
+
+static int __init dell_smbios_init(void)
+{
+	int ret;
+
+	dmi_walk(find_tokens, NULL);
+
+	if (!da_tokens)  {
+		pr_info("Unable to find dmi tokens\n");
+		return -ENODEV;
+	}
+
+	/*
+	 * Allocate buffer below 4GB for SMI data--only 32-bit physical addr
+	 * is passed to SMI handler.
+	 */
+	buffer = (void *)__get_free_page(GFP_KERNEL | GFP_DMA32);
+	if (!buffer) {
+		ret = -ENOMEM;
+		goto fail_buffer;
+	}
+
+	return 0;
+
+fail_buffer:
+	kfree(da_tokens);
+	return ret;
+}
+
+static void __exit dell_smbios_exit(void)
+{
+	kfree(da_tokens);
+	free_page((unsigned long)buffer);
+}
+
+subsys_initcall(dell_smbios_init);
+module_exit(dell_smbios_exit);
+
+MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
+MODULE_AUTHOR("Gabriele Mazzotta <gabriele.mzt@gmail.com>");
+MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
+MODULE_DESCRIPTION("Common functions for kernel modules using Dell SMBIOS");
+MODULE_LICENSE("GPL");