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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 <asm/semihosting.h>
#define SYSOPEN 0x01
#define SYSCLOSE 0x02
#define SYSREAD 0x06
#define SYSFLEN 0x0C
#define MODE_READ 0x0
#define MODE_READBIN 0x1
static int smh_read(int fd, void *memp, int len);
static int smh_open(const char *fname, char *modestr);
static int smh_close(int fd);
static int smh_len_fd(int fd);
/*
* Call the handler
*/
static int smh_trap(unsigned int sysnum, void *addr)
{
register int result asm("r0");
#if defined(CONFIG_ARM64)
asm volatile ("hlt #0xf000" : "=r" (result) : "0"(sysnum), "r"(addr));
#else
/* Note - untested placeholder */
asm volatile ("svc #0x123456" : "=r" (result) : "0"(sysnum), "r"(addr));
#endif
return result;
}
/*
* Open, load a file into memory, and close it. Check that the available space
* is sufficient to store the entire file. Return the bytes actually read from
* the file as seen by the read function. The verbose flag enables some extra
* printing of successful read status.
*/
int smh_load(const char *fname, void *memp, int avail, int verbose)
{
int ret, fd, len;
ret = -1;
debug("%s: fname \'%s\', avail %u, memp %p\n", __func__, fname,
avail, memp);
/* Open the file */
fd = smh_open(fname, "rb");
if (fd == -1)
return ret;
/* Get the file length */
ret = smh_len_fd(fd);
if (ret == -1) {
smh_close(fd);
return ret;
}
/* Check that the file will fit in the supplied buffer */
if (ret > avail) {
printf("%s: ERROR ret %d, avail %u\n", __func__, ret,
avail);
smh_close(fd);
return ret;
}
len = ret;
/* Read the file into the buffer */
ret = smh_read(fd, memp, len);
if (ret == 0) {
/* Print successful load information if requested */
if (verbose) {
printf("\n%s\n", fname);
printf(" 0x%8p dest\n", memp);
printf(" 0x%08x size\n", len);
printf(" 0x%08x avail\n", avail);
}
}
/* Close the file */
smh_close(fd);
return ret;
}
/*
* Read 'len' bytes of file into 'memp'. Returns 0 on success, else failure
*/
static int smh_read(int fd, void *memp, int len)
{
int ret;
struct smh_read_s {
int fd;
void *memp;
int len;
} read;
debug("%s: fd %d, memp %p, len %d\n", __func__, fd, memp, len);
read.fd = fd;
read.memp = memp;
read.len = len;
ret = smh_trap(SYSREAD, &read);
if (ret == 0) {
return 0;
} else {
/*
* 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 %d, fd %d, len %u memp %p\n",
__func__, ret, fd, len, memp);
}
return ret;
}
/*
* Open a file on the host. Mode is "r" or "rb" currently. Returns a file
* descriptor or -1 on error.
*/
static int smh_open(const char *fname, char *modestr)
{
int ret, fd, mode;
struct smh_open_s {
const char *fname;
unsigned int mode;
unsigned int len;
} open;
debug("%s: file \'%s\', mode \'%s\'\n", __func__, fname, modestr);
ret = -1;
/* 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 ret;
}
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 %d for file \'%s\'\n", __func__, fd,
fname);
return fd;
}
/*
* Close the file using the file descriptor
*/
static int smh_close(int fd)
{
int ret;
long fdlong;
debug("%s: fd %d\n", __func__, fd);
fdlong = (long)fd;
ret = smh_trap(SYSCLOSE, &fdlong);
if (ret == -1)
printf("%s: ERROR fd %d\n", __func__, fd);
return ret;
}
/*
* Get the file length from the file descriptor
*/
static int smh_len_fd(int fd)
{
int ret;
long fdlong;
debug("%s: fd %d\n", __func__, fd);
fdlong = (long)fd;
ret = smh_trap(SYSFLEN, &fdlong);
if (ret == -1)
printf("%s: ERROR ret %d\n", __func__, ret);
return ret;
}
/*
* Get the file length from the filename
*/
int smh_len(const char *fname)
{
int ret, fd, len;
debug("%s: file \'%s\'\n", __func__, fname);
/* Open the file */
fd = smh_open(fname, "rb");
if (fd == -1)
return fd;
/* Get the file length */
len = smh_len_fd(fd);
/* Close the file */
ret = smh_close(fd);
if (ret == -1)
return ret;
debug("%s: returning len %d\n", __func__, len);
/* Return the file length (or -1 error indication) */
return len;
}
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