xref: /openbmc/u-boot/lib/efi_loader/helloworld.c (revision 9d466f2f)
1 /*
2  * EFI hello world
3  *
4  * Copyright (c) 2016 Google, Inc
5  * Written by Simon Glass <sjg@chromium.org>
6  *
7  * SPDX-License-Identifier:     GPL-2.0+
8  *
9  * This program demonstrates calling a boottime service.
10  * It writes a greeting and the load options to the console.
11  */
12 
13 #include <common.h>
14 #include <efi_api.h>
15 
16 static const efi_guid_t loaded_image_guid = LOADED_IMAGE_GUID;
17 static const efi_guid_t fdt_guid = EFI_FDT_GUID;
18 static const efi_guid_t smbios_guid = SMBIOS_TABLE_GUID;
19 
20 static int hw_memcmp(const void *buf1, const void *buf2, size_t length)
21 {
22 	const u8 *pos1 = buf1;
23 	const u8 *pos2 = buf2;
24 
25 	for (; length; --length) {
26 		if (*pos1 != *pos2)
27 			return *pos1 - *pos2;
28 		++pos1;
29 		++pos2;
30 	}
31 	return 0;
32 }
33 
34 /*
35  * Entry point of the EFI application.
36  *
37  * @handle	handle of the loaded image
38  * @systable	system table
39  * @return	status code
40  */
41 efi_status_t EFIAPI efi_main(efi_handle_t handle,
42 			     struct efi_system_table *systable)
43 {
44 	struct efi_simple_text_output_protocol *con_out = systable->con_out;
45 	struct efi_boot_services *boottime = systable->boottime;
46 	struct efi_loaded_image *loaded_image;
47 	efi_status_t ret;
48 	efi_uintn_t i;
49 
50 	con_out->output_string(con_out, L"Hello, world!\n");
51 
52 	/* Get the loaded image protocol */
53 	ret = boottime->handle_protocol(handle, &loaded_image_guid,
54 					(void **)&loaded_image);
55 	if (ret != EFI_SUCCESS) {
56 		con_out->output_string(con_out,
57 				       L"Cannot open loaded image protocol\n");
58 		goto out;
59 	}
60 	/* Find configuration tables */
61 	for (i = 0; i < systable->nr_tables; ++i) {
62 		if (!hw_memcmp(&systable->tables[i].guid, &fdt_guid,
63 			       sizeof(efi_guid_t)))
64 			con_out->output_string(con_out, L"Have device tree\n");
65 		if (!hw_memcmp(&systable->tables[i].guid, &smbios_guid,
66 			       sizeof(efi_guid_t)))
67 			con_out->output_string(con_out, L"Have SMBIOS table\n");
68 	}
69 	/* Output the load options */
70 	con_out->output_string(con_out, L"Load options: ");
71 	if (loaded_image->load_options_size && loaded_image->load_options)
72 		con_out->output_string(con_out,
73 				       (u16 *)loaded_image->load_options);
74 	else
75 		con_out->output_string(con_out, L"<none>");
76 	con_out->output_string(con_out, L"\n");
77 
78 out:
79 	boottime->exit(handle, ret, 0, NULL);
80 
81 	/* We should never arrive here */
82 	return ret;
83 }
84