mbr/rs232-loader.c

   1 /*
   2     e07 bootloader suite
   3     Copyright (c) 2008 Daniel Mack <daniel@caiaq.de>
   4
   5     This program is free software: you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation, either version 3 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19 #define APPLICATION_TITLE "rs232 loader"
  20
  21 #include "application.h"
  22 #include <string.h>
  23
  24 #define ET_EXEC         2
  25 #define EM_C33          0x6b
  26
  27 #define ELFMAG0         0x7f
  28 #define ELFMAG1         0x45
  29 #define ELFMAG2         0x4c
  30 #define ELFMAG3         0x46
  31
  32 typedef struct {
  33         u8  e_ident[16];        /* ELF "magic number" */
  34         u16 e_type;             /* Identifies object file type */
  35         u16 e_machine;          /* Specifies required architecture */
  36         u32 e_version;          /* Identifies object file version */
  37         u32 e_entry;            /* Entry point virtual address */
  38         u32 e_phoff;            /* Program header table file offset */
  39         u32 e_shoff;            /* Section header table file offset */
  40         u32 e_flags;            /* Processor-specific flags */
  41         u16 e_ehsize;           /* ELF header size in bytes */
  42         u16 e_phentsize;        /* Program header table entry size */
  43         u16 e_phnum;            /* Program header table entry count */
  44         u16 e_shentsize;        /* Section header table entry size */
  45         u16 e_shnum;            /* Section header table entry count */
  46         u16 e_shstrndx;         /* Section header string table index */
  47 } __attribute__((packed)) elf32_hdr;
  48
  49 typedef struct {
  50         u32 sh_name;            /* Section name, index in string tbl */
  51         u32 sh_type;            /* Type of section */
  52         u32 sh_flags;           /* Miscellaneous section attributes */
  53         u32 sh_addr;            /* Section virtual addr at execution */
  54         u32 sh_offset;          /* Section file offset */
  55         u32 sh_size;            /* Size of section in bytes */
  56         u32 sh_link;            /* Index of another section */
  57         u32 sh_info;            /* Additional section information */
  58         u32 sh_addralign;       /* Section alignment */
  59         u32 sh_entsize;         /* Entry size if section holds table */
  60 } __attribute__((packed)) elf32_sec;
  61
  62 #define SHT_NULL        0       /* Section header table entry unused */
  63 #define SHT_PROGBITS    1       /* Program specific (private) data */
  64 #define SHT_SYMTAB      2       /* Link editing symbol table */
  65 #define SHT_STRTAB      3       /* A string table */
  66 #define SHT_RELA        4       /* Relocation entries with addends */
  67 #define SHT_HASH        5       /* A symbol hash table */
  68 #define SHT_DYNAMIC     6       /* Information for dynamic linking */
  69 #define SHT_NOTE        7       /* Information that marks file */
  70 #define SHT_NOBITS      8       /* Section occupies no space in file */
  71 #define SHT_REL         9       /* Relocation entries, no addends */
  72 #define SHT_SHLIB       10      /* Reserved, unspecified semantics */
  73 #define SHT_DYNSYM      11      /* Dynamic linking symbol table */
  74
  75 #define BUFFER (u8 *)(0x10000000 + 16 * 1024 * 1024)
  76
  77 void rs232_elf_load(void);
  78
  79 // this must be the first executable code as the loader executes from the first program address
  80 ReturnType rs232_loader(int block, int status)
  81 {
  82         APPLICATION_INITIALISE();
  83         rs232_elf_load();
  84         APPLICATION_FINALISE(0, 0);
  85 }
  86
  87 void rs232_elf_load(void)
  88 {
  89         u32 file_size;
  90         elf32_hdr *hdr;
  91         unsigned int i;
  92         void *exec;
  93         elf32_sec *sec;
  94
  95         print("Waiting for file from the serial line ... \n");
  96
  97         for (i = 0; i < sizeof(u32); i++) {
  98                 ((unsigned char *)&file_size)[i] = serial_input_char();
  99         }
 100
 101         for (i = 0; i < file_size; i++) {
 102                 (BUFFER)[i] = serial_input_char();
 103         }
 104
 105         hdr = (elf32_hdr *)BUFFER;
 106
 107         if (hdr->e_ident[0] != ELFMAG0 ||
 108               hdr->e_ident[1] != ELFMAG1 ||
 109               hdr->e_ident[2] != ELFMAG2 ||
 110               hdr->e_ident[3] != ELFMAG3) {
 111                 print("invalid ELF magic\n");
 112                 return;
 113         }
 114
 115         if (hdr->e_type != ET_EXEC) {
 116                 print("invalid ELF file type\n");
 117                 return;
 118         }
 119
 120         if (hdr->e_machine != EM_C33) {
 121                 print("FAIL: machine\n");
 122                 return;
 123         }
 124
 125         for (i = 0; i < hdr->e_shnum; i++) {
 126                 sec = (elf32_sec *)(BUFFER + (hdr->e_shoff + (sizeof(elf32_sec) * i)));
 127
 128                 switch (sec->sh_type) {
 129                 case SHT_PROGBITS:
 130                         memcpy((u8 *)sec->sh_addr, BUFFER + sec->sh_offset, sec->sh_size);
 131                         print("PROG: ");
 132                         print_u32(sec->sh_addr);
 133                         print("\n");
 134                         break;
 135                 case SHT_NOBITS:
 136                         /* clean .bss sections */
 137                         memset((u8 *)sec->sh_addr, 0, sec->sh_size);
 138                         break;
 139                 default:
 140                         break;
 141                 }
 142         }
 143
 144         print("EXEC from serial: ");
 145         print_u32(hdr->e_entry);
 146         print("\n");
 147
 148         exec = (void *)hdr->e_entry;
 149         ((void (*) (void)) exec) ();
 150 }
 151