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/*
* Copyright 2014 Broadcom Corporation
*
* SPDX-License-Identifier: GPL-2.0+
*/
/*
* Minimal semihosting implementation for reading files into memory. If more
* features like writing files or console output are required they can be
* added later. This code has been tested on arm64/aarch64 fastmodel only.
* An untested placeholder exists for armv7 architectures, but since they
* are commonly available in silicon now, fastmodel usage makes less sense
* for them.
*/
#include <common.h>
#include <command.h>
#define SYSOPEN 0x01
#define SYSCLOSE 0x02
#define SYSREAD 0x06
#define SYSFLEN 0x0C
#define MODE_READ 0x0
#define MODE_READBIN 0x1
/*
* Call the handler
*/
static noinline long smh_trap(unsigned int sysnum, void *addr)
{
register long result asm("r0");
#if defined(CONFIG_ARM64)
asm volatile ("hlt #0xf000" : "=r" (result) : "0"(sysnum), "r"(addr));
#elif defined(CONFIG_CPU_V7M)
asm volatile ("bkpt #0xAB" : "=r" (result) : "0"(sysnum), "r"(addr));
#else
/* Note - untested placeholder */
asm volatile ("svc #0x123456" : "=r" (result) : "0"(sysnum), "r"(addr));
#endif
return result;
}
/*
* Open a file on the host. Mode is "r" or "rb" currently. Returns a file
* descriptor or -1 on error.
*/
static long smh_open(const char *fname, char *modestr)
{
long fd;
unsigned long mode;
struct smh_open_s {
const char *fname;
unsigned long mode;
size_t len;
} open;
debug("%s: file \'%s\', mode \'%s\'\n", __func__, fname, modestr);
/* Check the file mode */
if (!(strcmp(modestr, "r"))) {
mode = MODE_READ;
} else if (!(strcmp(modestr, "rb"))) {
mode = MODE_READBIN;
} else {
printf("%s: ERROR mode \'%s\' not supported\n", __func__,
modestr);
return -1;
}
open.fname = fname;
open.len = strlen(fname);
open.mode = mode;
/* Open the file on the host */
fd = smh_trap(SYSOPEN, &open);
if (fd == -1)
printf("%s: ERROR fd %ld for file \'%s\'\n", __func__, fd,
fname);
return fd;
}
/*
* Read 'len' bytes of file into 'memp'. Returns 0 on success, else failure
*/
static long smh_read(long fd, void *memp, size_t len)
{
long ret;
struct smh_read_s {
long fd;
void *memp;
size_t len;
} read;
debug("%s: fd %ld, memp %p, len %zu\n", __func__, fd, memp, len);
read.fd = fd;
read.memp = memp;
read.len = len;
ret = smh_trap(SYSREAD, &read);
if (ret < 0) {
/*
* The ARM handler allows for returning partial lengths,
* but in practice this never happens so rather than create
* hard to maintain partial read loops and such, just fail
* with an error message.
*/
printf("%s: ERROR ret %ld, fd %ld, len %zu memp %p\n",
__func__, ret, fd, len, memp);
return -1;
}
return 0;
}
/*
* Close the file using the file descriptor
*/
static long smh_close(long fd)
{
long ret;
debug("%s: fd %ld\n", __func__, fd);
ret = smh_trap(SYSCLOSE, &fd);
if (ret == -1)
printf("%s: ERROR fd %ld\n", __func__, fd);
return ret;
}
/*
* Get the file length from the file descriptor
*/
static long smh_len_fd(long fd)
{
long ret;
debug("%s: fd %ld\n", __func__, fd);
ret = smh_trap(SYSFLEN, &fd);
if (ret == -1)
printf("%s: ERROR ret %ld, fd %ld\n", __func__, ret, fd);
return ret;
}
static int smh_load_file(const char * const name, ulong load_addr,
ulong *end_addr)
{
long fd;
long len;
long ret;
fd = smh_open(name, "rb");
if (fd == -1)
return -1;
len = smh_len_fd(fd);
if (len < 0) {
smh_close(fd);
return -1;
}
ret = smh_read(fd, (void *)load_addr, len);
smh_close(fd);
if (ret == 0) {
*end_addr = load_addr + len - 1;
printf("loaded file %s from %08lX to %08lX, %08lX bytes\n",
name,
load_addr,
*end_addr,
len);
} else {
printf("read failed\n");
return 0;
}
return 0;
}
static int do_smhload(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
if (argc == 3 || argc == 4) {
ulong load_addr;
ulong end_addr = 0;
ulong ret;
char end_str[64];
load_addr = simple_strtoul(argv[2], NULL, 16);
if (!load_addr)
return -1;
ret = smh_load_file(argv[1], load_addr, &end_addr);
if (ret < 0)
return 1;
/* Optionally save returned end to the environment */
if (argc == 4) {
sprintf(end_str, "0x%08lx", end_addr);
setenv(argv[3], end_str);
}
} else {
return CMD_RET_USAGE;
}
return 0;
}
U_BOOT_CMD(smhload, 4, 0, do_smhload, "load a file using semihosting",
"<file> 0x<address> [end var]\n"
" - load a semihosted file to the address specified\n"
" if the optional [end var] is specified, the end\n"
" address of the file will be stored in this environment\n"
" variable.\n");
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