1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright 2014 Broadcom Corporation
4 */
5
6 /*
7 * Minimal semihosting implementation for reading files into memory. If more
8 * features like writing files or console output are required they can be
9 * added later. This code has been tested on arm64/aarch64 fastmodel only.
10 * An untested placeholder exists for armv7 architectures, but since they
11 * are commonly available in silicon now, fastmodel usage makes less sense
12 * for them.
13 */
14 #include <common.h>
15 #include <command.h>
16 #include <env.h>
17 #include <log.h>
18
19 #define SYSOPEN 0x01
20 #define SYSCLOSE 0x02
21 #define SYSREAD 0x06
22 #define SYSFLEN 0x0C
23
24 #define MODE_READ 0x0
25 #define MODE_READBIN 0x1
26
27 /*
28 * Call the handler
29 */
smh_trap(unsigned int sysnum,void * addr)30 static noinline long smh_trap(unsigned int sysnum, void *addr)
31 {
32 register long result asm("r0");
33 #if defined(CONFIG_ARM64)
34 asm volatile ("hlt #0xf000" : "=r" (result) : "0"(sysnum), "r"(addr));
35 #elif defined(CONFIG_CPU_V7M)
36 asm volatile ("bkpt #0xAB" : "=r" (result) : "0"(sysnum), "r"(addr));
37 #else
38 /* Note - untested placeholder */
39 asm volatile ("svc #0x123456" : "=r" (result) : "0"(sysnum), "r"(addr));
40 #endif
41 return result;
42 }
43
44 /*
45 * Open a file on the host. Mode is "r" or "rb" currently. Returns a file
46 * descriptor or -1 on error.
47 */
smh_open(const char * fname,char * modestr)48 static long smh_open(const char *fname, char *modestr)
49 {
50 long fd;
51 unsigned long mode;
52 struct smh_open_s {
53 const char *fname;
54 unsigned long mode;
55 size_t len;
56 } open;
57
58 debug("%s: file \'%s\', mode \'%s\'\n", __func__, fname, modestr);
59
60 /* Check the file mode */
61 if (!(strcmp(modestr, "r"))) {
62 mode = MODE_READ;
63 } else if (!(strcmp(modestr, "rb"))) {
64 mode = MODE_READBIN;
65 } else {
66 printf("%s: ERROR mode \'%s\' not supported\n", __func__,
67 modestr);
68 return -1;
69 }
70
71 open.fname = fname;
72 open.len = strlen(fname);
73 open.mode = mode;
74
75 /* Open the file on the host */
76 fd = smh_trap(SYSOPEN, &open);
77 if (fd == -1)
78 printf("%s: ERROR fd %ld for file \'%s\'\n", __func__, fd,
79 fname);
80
81 return fd;
82 }
83
84 /*
85 * Read 'len' bytes of file into 'memp'. Returns 0 on success, else failure
86 */
smh_read(long fd,void * memp,size_t len)87 static long smh_read(long fd, void *memp, size_t len)
88 {
89 long ret;
90 struct smh_read_s {
91 long fd;
92 void *memp;
93 size_t len;
94 } read;
95
96 debug("%s: fd %ld, memp %p, len %zu\n", __func__, fd, memp, len);
97
98 read.fd = fd;
99 read.memp = memp;
100 read.len = len;
101
102 ret = smh_trap(SYSREAD, &read);
103 if (ret < 0) {
104 /*
105 * The ARM handler allows for returning partial lengths,
106 * but in practice this never happens so rather than create
107 * hard to maintain partial read loops and such, just fail
108 * with an error message.
109 */
110 printf("%s: ERROR ret %ld, fd %ld, len %zu memp %p\n",
111 __func__, ret, fd, len, memp);
112 return -1;
113 }
114
115 return 0;
116 }
117
118 /*
119 * Close the file using the file descriptor
120 */
smh_close(long fd)121 static long smh_close(long fd)
122 {
123 long ret;
124
125 debug("%s: fd %ld\n", __func__, fd);
126
127 ret = smh_trap(SYSCLOSE, &fd);
128 if (ret == -1)
129 printf("%s: ERROR fd %ld\n", __func__, fd);
130
131 return ret;
132 }
133
134 /*
135 * Get the file length from the file descriptor
136 */
smh_len_fd(long fd)137 static long smh_len_fd(long fd)
138 {
139 long ret;
140
141 debug("%s: fd %ld\n", __func__, fd);
142
143 ret = smh_trap(SYSFLEN, &fd);
144 if (ret == -1)
145 printf("%s: ERROR ret %ld, fd %ld\n", __func__, ret, fd);
146
147 return ret;
148 }
149
smh_load_file(const char * const name,ulong load_addr,ulong * end_addr)150 static int smh_load_file(const char * const name, ulong load_addr,
151 ulong *end_addr)
152 {
153 long fd;
154 long len;
155 long ret;
156
157 fd = smh_open(name, "rb");
158 if (fd == -1)
159 return -1;
160
161 len = smh_len_fd(fd);
162 if (len < 0) {
163 smh_close(fd);
164 return -1;
165 }
166
167 ret = smh_read(fd, (void *)load_addr, len);
168 smh_close(fd);
169
170 if (ret == 0) {
171 *end_addr = load_addr + len - 1;
172 printf("loaded file %s from %08lX to %08lX, %08lX bytes\n",
173 name,
174 load_addr,
175 *end_addr,
176 len);
177 } else {
178 printf("read failed\n");
179 return 0;
180 }
181
182 return 0;
183 }
184
do_smhload(struct cmd_tbl * cmdtp,int flag,int argc,char * const argv[])185 static int do_smhload(struct cmd_tbl *cmdtp, int flag, int argc,
186 char *const argv[])
187 {
188 if (argc == 3 || argc == 4) {
189 ulong load_addr;
190 ulong end_addr = 0;
191 int ret;
192 char end_str[64];
193
194 load_addr = simple_strtoul(argv[2], NULL, 16);
195 if (!load_addr)
196 return -1;
197
198 ret = smh_load_file(argv[1], load_addr, &end_addr);
199 if (ret < 0)
200 return CMD_RET_FAILURE;
201
202 /* Optionally save returned end to the environment */
203 if (argc == 4) {
204 sprintf(end_str, "0x%08lx", end_addr);
205 env_set(argv[3], end_str);
206 }
207 } else {
208 return CMD_RET_USAGE;
209 }
210 return 0;
211 }
212
213 U_BOOT_CMD(smhload, 4, 0, do_smhload, "load a file using semihosting",
214 "<file> 0x<address> [end var]\n"
215 " - load a semihosted file to the address specified\n"
216 " if the optional [end var] is specified, the end\n"
217 " address of the file will be stored in this environment\n"
218 " variable.\n");
219