1 // SPDX-License-Identifier: GPL-2.0-only
3 * Sample application for SMBIOS communication over WMI interface
4 * Performs the following:
5 * - Simple cmd_class/cmd_select lookup for TPM information
6 * - Simple query of known tokens and their values
7 * - Simple activation of a token
9 * Copyright (C) 2017 Dell, Inc.
16 #include <sys/ioctl.h>
19 /* if uapi header isn't installed, this might not yet exist */
21 #define __packed __attribute__((packed))
23 #include <linux/wmi.h>
25 /* It would be better to discover these using udev, but for a simple
26 * application they're hardcoded
28 static const char *ioctl_devfs = "/dev/wmi/dell-smbios";
29 static const char *token_sysfs =
30 "/sys/bus/platform/devices/dell-smbios.0/tokens";
32 static void show_buffer(struct dell_wmi_smbios_buffer *buffer)
34 printf("Call: %x/%x [%x,%x,%x,%x]\nResults: [%8x,%8x,%8x,%8x]\n",
35 buffer->std.cmd_class, buffer->std.cmd_select,
36 buffer->std.input[0], buffer->std.input[1],
37 buffer->std.input[2], buffer->std.input[3],
38 buffer->std.output[0], buffer->std.output[1],
39 buffer->std.output[2], buffer->std.output[3]);
42 static int run_wmi_smbios_cmd(struct dell_wmi_smbios_buffer *buffer)
47 fd = open(ioctl_devfs, O_NONBLOCK);
48 ret = ioctl(fd, DELL_WMI_SMBIOS_CMD, buffer);
53 static int find_token(__u16 token, __u16 *location, __u16 *value)
55 char location_sysfs[60];
61 ret = sprintf(value_sysfs, "%s/%04x_value", token_sysfs, token);
63 printf("sprintf value failed\n");
66 f = fopen(value_sysfs, "rb");
68 printf("failed to open %s\n", value_sysfs);
71 fread(buf, 1, 4096, f);
73 *value = (__u16) strtol(buf, NULL, 16);
75 ret = sprintf(location_sysfs, "%s/%04x_location", token_sysfs, token);
77 printf("sprintf location failed\n");
80 f = fopen(location_sysfs, "rb");
82 printf("failed to open %s\n", location_sysfs);
85 fread(buf, 1, 4096, f);
87 *location = (__u16) strtol(buf, NULL, 16);
94 static int token_is_active(__u16 *location, __u16 *cmpvalue,
95 struct dell_wmi_smbios_buffer *buffer)
99 buffer->std.cmd_class = CLASS_TOKEN_READ;
100 buffer->std.cmd_select = SELECT_TOKEN_STD;
101 buffer->std.input[0] = *location;
102 ret = run_wmi_smbios_cmd(buffer);
103 if (ret != 0 || buffer->std.output[0] != 0)
105 ret = (buffer->std.output[1] == *cmpvalue);
109 static int query_token(__u16 token, struct dell_wmi_smbios_buffer *buffer)
115 ret = find_token(token, &location, &value);
117 printf("unable to find token %04x\n", token);
120 return token_is_active(&location, &value, buffer);
123 static int activate_token(struct dell_wmi_smbios_buffer *buffer,
130 ret = find_token(token, &location, &value);
132 printf("unable to find token %04x\n", token);
135 buffer->std.cmd_class = CLASS_TOKEN_WRITE;
136 buffer->std.cmd_select = SELECT_TOKEN_STD;
137 buffer->std.input[0] = location;
138 buffer->std.input[1] = 1;
139 ret = run_wmi_smbios_cmd(buffer);
143 static int query_buffer_size(__u64 *buffer_size)
147 f = fopen(ioctl_devfs, "rb");
150 fread(buffer_size, sizeof(__u64), 1, f);
157 struct dell_wmi_smbios_buffer *buffer;
161 ret = query_buffer_size(&value);
162 if (ret == EXIT_FAILURE || !value) {
163 printf("Unable to read buffer size\n");
166 printf("Detected required buffer size %lld\n", value);
168 buffer = malloc(value);
169 if (buffer == NULL) {
170 printf("failed to alloc memory for ioctl\n");
174 buffer->length = value;
176 /* simple SMBIOS call for looking up TPM info */
177 buffer->std.cmd_class = CLASS_FLASH_INTERFACE;
178 buffer->std.cmd_select = SELECT_FLASH_INTERFACE;
179 buffer->std.input[0] = 2;
180 ret = run_wmi_smbios_cmd(buffer);
182 printf("smbios ioctl failed: %d\n", ret);
188 /* query some tokens */
189 ret = query_token(CAPSULE_EN_TOKEN, buffer);
190 printf("UEFI Capsule enabled token is: %d\n", ret);
191 ret = query_token(CAPSULE_DIS_TOKEN, buffer);
192 printf("UEFI Capsule disabled token is: %d\n", ret);
194 /* activate UEFI capsule token if disabled */
196 printf("Enabling UEFI capsule token");
197 if (activate_token(buffer, CAPSULE_EN_TOKEN)) {
198 printf("activate failed\n");