lib/efi_loader/helloworld.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * EFI hello world
   4  *
   5  * Copyright (c) 2016 Google, Inc
   6  * Written by Simon Glass <sjg@chromium.org>
   7  *
   8  * This program demonstrates calling a boottime service.
   9  * It writes a greeting and the load options to the console.
  10  */
  11
  12 #include <common.h>
  13 #include <efi_api.h>
  14
  15 static const efi_guid_t loaded_image_guid = EFI_LOADED_IMAGE_PROTOCOL_GUID;
  16 static const efi_guid_t fdt_guid = EFI_FDT_GUID;
  17 static const efi_guid_t acpi_guid = EFI_ACPI_TABLE_GUID;
  18 static const efi_guid_t smbios_guid = SMBIOS_TABLE_GUID;
  19
  20 /**
  21  * efi_main() - entry point of the EFI application.
  22  *
  23  * @handle:     handle of the loaded image
  24  * @systable:   system table
  25  * @return:     status code
  26  */
  27 efi_status_t EFIAPI efi_main(efi_handle_t handle,
  28                              struct efi_system_table *systable)
  29 {
  30         struct efi_simple_text_output_protocol *con_out = systable->con_out;
  31         struct efi_boot_services *boottime = systable->boottime;
  32         struct efi_loaded_image *loaded_image;
  33         efi_status_t ret;
  34         efi_uintn_t i;
  35         u16 rev[] = L"0.0.0";
  36
  37         /* UEFI requires CR LF */
  38         con_out->output_string(con_out, L"Hello, world!\r\n");
  39
  40         /* Print the revision number */
  41         rev[0] = (systable->hdr.revision >> 16) + '0';
  42         rev[4] = systable->hdr.revision & 0xffff;
  43         for (; rev[4] >= 10;) {
  44                 rev[4] -= 10;
  45                 ++rev[2];
  46         }
  47         /* Third digit is only to be shown if non-zero */
  48         if (rev[4])
  49                 rev[4] += '0';
  50         else
  51                 rev[3] = 0;
  52
  53         con_out->output_string(con_out, L"Running on UEFI ");
  54         con_out->output_string(con_out, rev);
  55         con_out->output_string(con_out, L"\r\n");
  56
  57         /* Get the loaded image protocol */
  58         ret = boottime->handle_protocol(handle, &loaded_image_guid,
  59                                         (void **)&loaded_image);
  60         if (ret != EFI_SUCCESS) {
  61                 con_out->output_string
  62                         (con_out, L"Cannot open loaded image protocol\r\n");
  63                 goto out;
  64         }
  65         /* Find configuration tables */
  66         for (i = 0; i < systable->nr_tables; ++i) {
  67                 if (!memcmp(&systable->tables[i].guid, &fdt_guid,
  68                             sizeof(efi_guid_t)))
  69                         con_out->output_string
  70                                         (con_out, L"Have device tree\r\n");
  71                 if (!memcmp(&systable->tables[i].guid, &acpi_guid,
  72                             sizeof(efi_guid_t)))
  73                         con_out->output_string
  74                                         (con_out, L"Have ACPI 2.0 table\r\n");
  75                 if (!memcmp(&systable->tables[i].guid, &smbios_guid,
  76                             sizeof(efi_guid_t)))
  77                         con_out->output_string
  78                                         (con_out, L"Have SMBIOS table\r\n");
  79         }
  80         /* Output the load options */
  81         con_out->output_string(con_out, L"Load options: ");
  82         if (loaded_image->load_options_size && loaded_image->load_options)
  83                 con_out->output_string(con_out,
  84                                        (u16 *)loaded_image->load_options);
  85         else
  86                 con_out->output_string(con_out, L"<none>");
  87         con_out->output_string(con_out, L"\r\n");
  88
  89 out:
  90         boottime->exit(handle, ret, 0, NULL);
  91
  92         /* We should never arrive here */
  93         return ret;
  94 }