d8f186aa4a
Add an API that utilizes the ARM semihosting mechanism to interact with the host system when a device is being emulated or run under a debugger. RISCV is implemented in terms of the ARM implementation, and therefore the ARM definitions cross enough architectures to be defined 'common'. Functionality is exposed as a separate API instead of syscall implementations (`_lseek`, `_open`, etc) due to various quirks with the ARM mechanisms that means function arguments are not standard. For more information see: https://developer.arm.com/documentation/dui0471/m/what-is-semihosting- Signed-off-by: Jordan Yates <jordan.yates@data61.csiro.au> impl
132 lines
2.1 KiB
C
132 lines
2.1 KiB
C
/*
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* Copyright (c) 2022, Commonwealth Scientific and Industrial Research
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* Organisation (CSIRO) ABN 41 687 119 230.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <string.h>
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#include <zephyr/kernel.h>
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#include <zephyr/arch/common/semihost.h>
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struct semihost_poll_in_args {
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long zero;
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} __packed;
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struct semihost_open_args {
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const char *path;
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long mode;
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long path_len;
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} __packed;
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struct semihost_close_args {
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long fd;
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} __packed;
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struct semihost_flen_args {
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long fd;
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} __packed;
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struct semihost_seek_args {
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long fd;
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long offset;
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} __packed;
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struct semihost_read_args {
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long fd;
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char *buf;
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long len;
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} __packed;
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struct semihost_write_args {
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long fd;
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const char *buf;
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long len;
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} __packed;
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char semihost_poll_in(void)
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{
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struct semihost_poll_in_args args = {
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.zero = 0
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};
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return (char)semihost_exec(SEMIHOST_READC, &args);
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}
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void semihost_poll_out(char c)
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{
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/* WRITEC takes a pointer directly to the character */
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(void)semihost_exec(SEMIHOST_WRITEC, &c);
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}
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long semihost_open(const char *path, long mode)
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{
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struct semihost_open_args args = {
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.path = path,
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.mode = mode,
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.path_len = strlen(path)
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};
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return semihost_exec(SEMIHOST_OPEN, &args);
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}
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long semihost_close(long fd)
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{
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struct semihost_close_args args = {
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.fd = fd
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};
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return semihost_exec(SEMIHOST_CLOSE, &args);
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}
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long semihost_flen(long fd)
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{
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struct semihost_flen_args args = {
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.fd = fd
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};
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return semihost_exec(SEMIHOST_FLEN, &args);
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}
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long semihost_seek(long fd, long offset)
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{
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struct semihost_seek_args args = {
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.fd = fd,
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.offset = offset
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};
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return semihost_exec(SEMIHOST_SEEK, &args);
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}
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long semihost_read(long fd, void *buf, long len)
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{
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struct semihost_read_args args = {
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.fd = fd,
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.buf = buf,
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.len = len
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};
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long ret;
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ret = semihost_exec(SEMIHOST_READ, &args);
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/* EOF condition */
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if (ret == len) {
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ret = -EIO;
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}
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/* All bytes read */
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else if (ret == 0) {
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ret = len;
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}
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return ret;
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}
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long semihost_write(long fd, const void *buf, long len)
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{
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struct semihost_write_args args = {
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.fd = fd,
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.buf = buf,
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.len = len
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};
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return semihost_exec(SEMIHOST_WRITE, &args);
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}
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