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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2022 Sean Anderson <sean.anderson@seco.com>
* Copyright 2014 Broadcom Corporation
*/
/*
* 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 <log.h>
#include <semihosting.h>
#define SYSOPEN 0x01
#define SYSCLOSE 0x02
#define SYSWRITE 0x05
#define SYSREAD 0x06
#define SYSSEEK 0x0A
#define SYSFLEN 0x0C
#define SYSERRNO 0x13
/*
* 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;
}
/**
* smh_errno() - Read the host's errno
*
* This gets the value of the host's errno and negates it. The host's errno may
* or may not be set, so only call this function if a previous semihosting call
* has failed.
*
* Return: a negative error value
*/
static int smh_errno(void)
{
long ret = smh_trap(SYSERRNO, NULL);
if (ret > 0 && ret < INT_MAX)
return -ret;
return -EIO;
}
long smh_open(const char *fname, enum smh_open_mode mode)
{
long fd;
struct smh_open_s {
const char *fname;
unsigned long mode;
size_t len;
} open;
debug("%s: file \'%s\', mode \'%u\'\n", __func__, fname, mode);
open.fname = fname;
open.len = strlen(fname);
open.mode = mode;
/* Open the file on the host */
fd = smh_trap(SYSOPEN, &open);
if (fd == -1)
return smh_errno();
return fd;
}
/**
* struct smg_rdwr_s - Arguments for read and write
* @fd: A file descriptor returned from smh_open()
* @memp: Pointer to a buffer of memory of at least @len bytes
* @len: The number of bytes to read or write
*/
struct smh_rdwr_s {
long fd;
void *memp;
size_t len;
};
long smh_read(long fd, void *memp, size_t len)
{
long ret;
struct smh_rdwr_s 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)
return smh_errno();
return len - ret;
}
long smh_write(long fd, const void *memp, size_t len, ulong *written)
{
long ret;
struct smh_rdwr_s write;
debug("%s: fd %ld, memp %p, len %zu\n", __func__, fd, memp, len);
write.fd = fd;
write.memp = (void *)memp;
write.len = len;
ret = smh_trap(SYSWRITE, &write);
*written = len - ret;
if (ret)
return smh_errno();
return 0;
}
long smh_close(long fd)
{
long ret;
debug("%s: fd %ld\n", __func__, fd);
ret = smh_trap(SYSCLOSE, &fd);
if (ret == -1)
return smh_errno();
return 0;
}
long smh_flen(long fd)
{
long ret;
debug("%s: fd %ld\n", __func__, fd);
ret = smh_trap(SYSFLEN, &fd);
if (ret == -1)
return smh_errno();
return ret;
}
long smh_seek(long fd, long pos)
{
long ret;
struct smh_seek_s {
long fd;
long pos;
} seek;
debug("%s: fd %ld pos %ld\n", __func__, fd, pos);
seek.fd = fd;
seek.pos = pos;
ret = smh_trap(SYSSEEK, &seek);
if (ret)
return smh_errno();
return 0;
}
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