1 /* 2 * Copyright 2014 Broadcom Corporation 3 * 4 * SPDX-License-Identifier: GPL-2.0+ 5 */ 6 7 /* 8 * Minimal semihosting implementation for reading files into memory. If more 9 * features like writing files or console output are required they can be 10 * added later. This code has been tested on arm64/aarch64 fastmodel only. 11 * An untested placeholder exists for armv7 architectures, but since they 12 * are commonly available in silicon now, fastmodel usage makes less sense 13 * for them. 14 */ 15 #include <common.h> 16 #include <command.h> 17 18 #define SYSOPEN 0x01 19 #define SYSCLOSE 0x02 20 #define SYSREAD 0x06 21 #define SYSFLEN 0x0C 22 23 #define MODE_READ 0x0 24 #define MODE_READBIN 0x1 25 26 /* 27 * Call the handler 28 */ 29 static noinline long smh_trap(unsigned int sysnum, void *addr) 30 { 31 register long result asm("r0"); 32 #if defined(CONFIG_ARM64) 33 asm volatile ("hlt #0xf000" : "=r" (result) : "0"(sysnum), "r"(addr)); 34 #elif defined(CONFIG_CPU_V7M) 35 asm volatile ("bkpt #0xAB" : "=r" (result) : "0"(sysnum), "r"(addr)); 36 #else 37 /* Note - untested placeholder */ 38 asm volatile ("svc #0x123456" : "=r" (result) : "0"(sysnum), "r"(addr)); 39 #endif 40 return result; 41 } 42 43 /* 44 * Open a file on the host. Mode is "r" or "rb" currently. Returns a file 45 * descriptor or -1 on error. 46 */ 47 static long smh_open(const char *fname, char *modestr) 48 { 49 long fd; 50 unsigned long mode; 51 struct smh_open_s { 52 const char *fname; 53 unsigned long mode; 54 size_t len; 55 } open; 56 57 debug("%s: file \'%s\', mode \'%s\'\n", __func__, fname, modestr); 58 59 /* Check the file mode */ 60 if (!(strcmp(modestr, "r"))) { 61 mode = MODE_READ; 62 } else if (!(strcmp(modestr, "rb"))) { 63 mode = MODE_READBIN; 64 } else { 65 printf("%s: ERROR mode \'%s\' not supported\n", __func__, 66 modestr); 67 return -1; 68 } 69 70 open.fname = fname; 71 open.len = strlen(fname); 72 open.mode = mode; 73 74 /* Open the file on the host */ 75 fd = smh_trap(SYSOPEN, &open); 76 if (fd == -1) 77 printf("%s: ERROR fd %ld for file \'%s\'\n", __func__, fd, 78 fname); 79 80 return fd; 81 } 82 83 /* 84 * Read 'len' bytes of file into 'memp'. Returns 0 on success, else failure 85 */ 86 static long smh_read(long fd, void *memp, size_t len) 87 { 88 long ret; 89 struct smh_read_s { 90 long fd; 91 void *memp; 92 size_t len; 93 } read; 94 95 debug("%s: fd %ld, memp %p, len %zu\n", __func__, fd, memp, len); 96 97 read.fd = fd; 98 read.memp = memp; 99 read.len = len; 100 101 ret = smh_trap(SYSREAD, &read); 102 if (ret < 0) { 103 /* 104 * The ARM handler allows for returning partial lengths, 105 * but in practice this never happens so rather than create 106 * hard to maintain partial read loops and such, just fail 107 * with an error message. 108 */ 109 printf("%s: ERROR ret %ld, fd %ld, len %zu memp %p\n", 110 __func__, ret, fd, len, memp); 111 return -1; 112 } 113 114 return 0; 115 } 116 117 /* 118 * Close the file using the file descriptor 119 */ 120 static long smh_close(long fd) 121 { 122 long ret; 123 124 debug("%s: fd %ld\n", __func__, fd); 125 126 ret = smh_trap(SYSCLOSE, &fd); 127 if (ret == -1) 128 printf("%s: ERROR fd %ld\n", __func__, fd); 129 130 return ret; 131 } 132 133 /* 134 * Get the file length from the file descriptor 135 */ 136 static long smh_len_fd(long fd) 137 { 138 long ret; 139 140 debug("%s: fd %ld\n", __func__, fd); 141 142 ret = smh_trap(SYSFLEN, &fd); 143 if (ret == -1) 144 printf("%s: ERROR ret %ld, fd %ld\n", __func__, ret, fd); 145 146 return ret; 147 } 148 149 static int smh_load_file(const char * const name, ulong load_addr, 150 ulong *end_addr) 151 { 152 long fd; 153 long len; 154 long ret; 155 156 fd = smh_open(name, "rb"); 157 if (fd == -1) 158 return -1; 159 160 len = smh_len_fd(fd); 161 if (len < 0) { 162 smh_close(fd); 163 return -1; 164 } 165 166 ret = smh_read(fd, (void *)load_addr, len); 167 smh_close(fd); 168 169 if (ret == 0) { 170 *end_addr = load_addr + len - 1; 171 printf("loaded file %s from %08lX to %08lX, %08lX bytes\n", 172 name, 173 load_addr, 174 *end_addr, 175 len); 176 } else { 177 printf("read failed\n"); 178 return 0; 179 } 180 181 return 0; 182 } 183 184 static int do_smhload(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) 185 { 186 if (argc == 3 || argc == 4) { 187 ulong load_addr; 188 ulong end_addr = 0; 189 int ret; 190 char end_str[64]; 191 192 load_addr = simple_strtoul(argv[2], NULL, 16); 193 if (!load_addr) 194 return -1; 195 196 ret = smh_load_file(argv[1], load_addr, &end_addr); 197 if (ret < 0) 198 return CMD_RET_FAILURE; 199 200 /* Optionally save returned end to the environment */ 201 if (argc == 4) { 202 sprintf(end_str, "0x%08lx", end_addr); 203 env_set(argv[3], end_str); 204 } 205 } else { 206 return CMD_RET_USAGE; 207 } 208 return 0; 209 } 210 211 U_BOOT_CMD(smhload, 4, 0, do_smhload, "load a file using semihosting", 212 "<file> 0x<address> [end var]\n" 213 " - load a semihosted file to the address specified\n" 214 " if the optional [end var] is specified, the end\n" 215 " address of the file will be stored in this environment\n" 216 " variable.\n"); 217