433 lines
10 KiB
C
433 lines
10 KiB
C
/*
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* Common functions for kernel modules using Dell SMBIOS
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*
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* Copyright (c) Red Hat <mjg@redhat.com>
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* Copyright (c) 2014 Gabriele Mazzotta <gabriele.mzt@gmail.com>
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* Copyright (c) 2014 Pali Rohár <pali.rohar@gmail.com>
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*
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* Based on documentation in the libsmbios package:
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* Copyright (C) 2005-2014 Dell Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/capability.h>
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#include <linux/dmi.h>
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#include <linux/err.h>
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#include <linux/gfp.h>
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#include <linux/mutex.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/io.h>
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#include "../../firmware/dcdbas.h"
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#include "dell-smbios.h"
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struct calling_interface_structure {
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struct dmi_header header;
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u16 cmdIOAddress;
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u8 cmdIOCode;
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u32 supportedCmds;
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struct calling_interface_token tokens[];
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} __packed;
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static struct calling_interface_buffer *buffer;
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static DEFINE_MUTEX(buffer_mutex);
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static int da_command_address;
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static int da_command_code;
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static int da_num_tokens;
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static struct platform_device *platform_device;
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static struct calling_interface_token *da_tokens;
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static struct device_attribute *token_location_attrs;
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static struct device_attribute *token_value_attrs;
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static struct attribute **token_attrs;
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int dell_smbios_error(int value)
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{
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switch (value) {
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case 0: /* Completed successfully */
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return 0;
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case -1: /* Completed with error */
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return -EIO;
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case -2: /* Function not supported */
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return -ENXIO;
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default: /* Unknown error */
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return -EINVAL;
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}
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}
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EXPORT_SYMBOL_GPL(dell_smbios_error);
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struct calling_interface_buffer *dell_smbios_get_buffer(void)
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{
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mutex_lock(&buffer_mutex);
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dell_smbios_clear_buffer();
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return buffer;
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}
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EXPORT_SYMBOL_GPL(dell_smbios_get_buffer);
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void dell_smbios_clear_buffer(void)
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{
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memset(buffer, 0, sizeof(struct calling_interface_buffer));
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}
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EXPORT_SYMBOL_GPL(dell_smbios_clear_buffer);
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void dell_smbios_release_buffer(void)
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{
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mutex_unlock(&buffer_mutex);
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}
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EXPORT_SYMBOL_GPL(dell_smbios_release_buffer);
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void dell_smbios_send_request(int class, int select)
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{
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struct smi_cmd command;
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command.magic = SMI_CMD_MAGIC;
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command.command_address = da_command_address;
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command.command_code = da_command_code;
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command.ebx = virt_to_phys(buffer);
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command.ecx = 0x42534931;
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buffer->cmd_class = class;
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buffer->cmd_select = select;
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dcdbas_smi_request(&command);
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}
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EXPORT_SYMBOL_GPL(dell_smbios_send_request);
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struct calling_interface_token *dell_smbios_find_token(int tokenid)
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{
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int i;
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for (i = 0; i < da_num_tokens; i++) {
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if (da_tokens[i].tokenID == tokenid)
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return &da_tokens[i];
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}
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return NULL;
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}
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EXPORT_SYMBOL_GPL(dell_smbios_find_token);
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static BLOCKING_NOTIFIER_HEAD(dell_laptop_chain_head);
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int dell_laptop_register_notifier(struct notifier_block *nb)
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{
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return blocking_notifier_chain_register(&dell_laptop_chain_head, nb);
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}
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EXPORT_SYMBOL_GPL(dell_laptop_register_notifier);
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int dell_laptop_unregister_notifier(struct notifier_block *nb)
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{
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return blocking_notifier_chain_unregister(&dell_laptop_chain_head, nb);
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}
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EXPORT_SYMBOL_GPL(dell_laptop_unregister_notifier);
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void dell_laptop_call_notifier(unsigned long action, void *data)
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{
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blocking_notifier_call_chain(&dell_laptop_chain_head, action, data);
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}
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EXPORT_SYMBOL_GPL(dell_laptop_call_notifier);
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static void __init parse_da_table(const struct dmi_header *dm)
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{
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/* Final token is a terminator, so we don't want to copy it */
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int tokens = (dm->length-11)/sizeof(struct calling_interface_token)-1;
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struct calling_interface_token *new_da_tokens;
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struct calling_interface_structure *table =
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container_of(dm, struct calling_interface_structure, header);
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/* 4 bytes of table header, plus 7 bytes of Dell header, plus at least
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6 bytes of entry */
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if (dm->length < 17)
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return;
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da_command_address = table->cmdIOAddress;
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da_command_code = table->cmdIOCode;
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new_da_tokens = krealloc(da_tokens, (da_num_tokens + tokens) *
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sizeof(struct calling_interface_token),
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GFP_KERNEL);
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if (!new_da_tokens)
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return;
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da_tokens = new_da_tokens;
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memcpy(da_tokens+da_num_tokens, table->tokens,
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sizeof(struct calling_interface_token) * tokens);
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da_num_tokens += tokens;
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}
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static void zero_duplicates(struct device *dev)
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{
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int i, j;
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for (i = 0; i < da_num_tokens; i++) {
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if (da_tokens[i].tokenID == 0)
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continue;
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for (j = i+1; j < da_num_tokens; j++) {
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if (da_tokens[j].tokenID == 0)
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continue;
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if (da_tokens[i].tokenID == da_tokens[j].tokenID) {
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dev_dbg(dev, "Zeroing dup token ID %x(%x/%x)\n",
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da_tokens[j].tokenID,
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da_tokens[j].location,
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da_tokens[j].value);
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da_tokens[j].tokenID = 0;
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}
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}
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}
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}
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static void __init find_tokens(const struct dmi_header *dm, void *dummy)
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{
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switch (dm->type) {
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case 0xd4: /* Indexed IO */
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case 0xd5: /* Protected Area Type 1 */
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case 0xd6: /* Protected Area Type 2 */
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break;
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case 0xda: /* Calling interface */
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parse_da_table(dm);
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break;
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}
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}
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static int match_attribute(struct device *dev,
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struct device_attribute *attr)
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{
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int i;
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for (i = 0; i < da_num_tokens * 2; i++) {
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if (!token_attrs[i])
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continue;
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if (strcmp(token_attrs[i]->name, attr->attr.name) == 0)
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return i/2;
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}
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dev_dbg(dev, "couldn't match: %s\n", attr->attr.name);
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return -EINVAL;
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}
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static ssize_t location_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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int i;
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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i = match_attribute(dev, attr);
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if (i > 0)
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return scnprintf(buf, PAGE_SIZE, "%08x", da_tokens[i].location);
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return 0;
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}
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static ssize_t value_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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int i;
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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i = match_attribute(dev, attr);
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if (i > 0)
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return scnprintf(buf, PAGE_SIZE, "%08x", da_tokens[i].value);
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return 0;
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}
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static struct attribute_group smbios_attribute_group = {
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.name = "tokens"
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};
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static struct platform_driver platform_driver = {
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.driver = {
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.name = "dell-smbios",
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},
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};
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static int build_tokens_sysfs(struct platform_device *dev)
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{
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char buffer_location[13];
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char buffer_value[10];
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char *location_name;
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char *value_name;
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size_t size;
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int ret;
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int i, j;
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/* (number of tokens + 1 for null terminated */
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size = sizeof(struct device_attribute) * (da_num_tokens + 1);
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token_location_attrs = kzalloc(size, GFP_KERNEL);
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if (!token_location_attrs)
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return -ENOMEM;
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token_value_attrs = kzalloc(size, GFP_KERNEL);
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if (!token_value_attrs)
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goto out_allocate_value;
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/* need to store both location and value + terminator*/
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size = sizeof(struct attribute *) * ((2 * da_num_tokens) + 1);
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token_attrs = kzalloc(size, GFP_KERNEL);
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if (!token_attrs)
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goto out_allocate_attrs;
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for (i = 0, j = 0; i < da_num_tokens; i++) {
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/* skip empty */
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if (da_tokens[i].tokenID == 0)
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continue;
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/* add location */
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sprintf(buffer_location, "%04x_location",
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da_tokens[i].tokenID);
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location_name = kstrdup(buffer_location, GFP_KERNEL);
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if (location_name == NULL)
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goto out_unwind_strings;
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sysfs_attr_init(&token_location_attrs[i].attr);
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token_location_attrs[i].attr.name = location_name;
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token_location_attrs[i].attr.mode = 0444;
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token_location_attrs[i].show = location_show;
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token_attrs[j++] = &token_location_attrs[i].attr;
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/* add value */
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sprintf(buffer_value, "%04x_value",
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da_tokens[i].tokenID);
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value_name = kstrdup(buffer_value, GFP_KERNEL);
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if (value_name == NULL)
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goto loop_fail_create_value;
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sysfs_attr_init(&token_value_attrs[i].attr);
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token_value_attrs[i].attr.name = value_name;
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token_value_attrs[i].attr.mode = 0444;
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token_value_attrs[i].show = value_show;
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token_attrs[j++] = &token_value_attrs[i].attr;
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continue;
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loop_fail_create_value:
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kfree(value_name);
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goto out_unwind_strings;
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}
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smbios_attribute_group.attrs = token_attrs;
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ret = sysfs_create_group(&dev->dev.kobj, &smbios_attribute_group);
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if (ret)
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goto out_unwind_strings;
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return 0;
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out_unwind_strings:
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for (i = i-1; i > 0; i--) {
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kfree(token_location_attrs[i].attr.name);
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kfree(token_value_attrs[i].attr.name);
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}
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kfree(token_attrs);
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out_allocate_attrs:
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kfree(token_value_attrs);
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out_allocate_value:
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kfree(token_location_attrs);
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return -ENOMEM;
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}
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static void free_group(struct platform_device *pdev)
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{
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int i;
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sysfs_remove_group(&pdev->dev.kobj,
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&smbios_attribute_group);
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for (i = 0; i < da_num_tokens; i++) {
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kfree(token_location_attrs[i].attr.name);
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kfree(token_value_attrs[i].attr.name);
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}
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kfree(token_attrs);
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kfree(token_value_attrs);
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kfree(token_location_attrs);
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}
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static int __init dell_smbios_init(void)
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{
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const struct dmi_device *valid;
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int ret;
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valid = dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL);
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if (!valid) {
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pr_err("Unable to run on non-Dell system\n");
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return -ENODEV;
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}
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dmi_walk(find_tokens, NULL);
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if (!da_tokens) {
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pr_info("Unable to find dmi tokens\n");
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return -ENODEV;
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}
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/*
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* Allocate buffer below 4GB for SMI data--only 32-bit physical addr
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* is passed to SMI handler.
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*/
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buffer = (void *)__get_free_page(GFP_KERNEL | GFP_DMA32);
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if (!buffer) {
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ret = -ENOMEM;
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goto fail_buffer;
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}
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ret = platform_driver_register(&platform_driver);
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if (ret)
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goto fail_platform_driver;
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platform_device = platform_device_alloc("dell-smbios", 0);
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if (!platform_device) {
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ret = -ENOMEM;
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goto fail_platform_device_alloc;
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}
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ret = platform_device_add(platform_device);
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if (ret)
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goto fail_platform_device_add;
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/* duplicate tokens will cause problems building sysfs files */
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zero_duplicates(&platform_device->dev);
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ret = build_tokens_sysfs(platform_device);
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if (ret)
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goto fail_create_group;
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return 0;
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fail_create_group:
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platform_device_del(platform_device);
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fail_platform_device_add:
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platform_device_put(platform_device);
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fail_platform_device_alloc:
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platform_driver_unregister(&platform_driver);
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fail_platform_driver:
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free_page((unsigned long)buffer);
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fail_buffer:
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kfree(da_tokens);
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return ret;
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}
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static void __exit dell_smbios_exit(void)
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{
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if (platform_device) {
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free_group(platform_device);
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platform_device_unregister(platform_device);
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platform_driver_unregister(&platform_driver);
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}
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free_page((unsigned long)buffer);
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kfree(da_tokens);
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}
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subsys_initcall(dell_smbios_init);
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module_exit(dell_smbios_exit);
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MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
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MODULE_AUTHOR("Gabriele Mazzotta <gabriele.mzt@gmail.com>");
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MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
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MODULE_DESCRIPTION("Common functions for kernel modules using Dell SMBIOS");
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MODULE_LICENSE("GPL");
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