target/xtensa: add file-IO support

- Manual integration of File-IO support from xt0.2 release
- Verified with applications linked using gdbio LSP
- No new clang static analysis warnings

Signed-off-by: Ian Thompson <ianst@cadence.com>
Change-Id: Iedc5f885b2548097ef4f11ae1a675b5944f5fdf0
Reviewed-on: https://review.openocd.org/c/openocd/+/7550
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

src/target/xtensa/xtensa_fileio.h

@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/***************************************************************************
+ *   Xtensa Target File-I/O Support for OpenOCD                            *
+ *   Copyright (C) 2020-2023 Cadence Design Systems, Inc.                  *
+ ***************************************************************************/
+
+#ifndef OPENOCD_TARGET_XTENSA_FILEIO_H
+#define OPENOCD_TARGET_XTENSA_FILEIO_H
+
+#include <target/target.h>
+#include <helper/command.h>
+#include "xtensa.h"
+
+#define XTENSA_SYSCALL_OP_REG		XT_REG_IDX_A2
+#define XTENSA_SYSCALL_RETVAL_REG	XT_REG_IDX_A2
+#define XTENSA_SYSCALL_ERRNO_REG	XT_REG_IDX_A3
+
+#define XTENSA_SYSCALL_OPEN			(-2)
+#define XTENSA_SYSCALL_CLOSE		(-3)
+#define XTENSA_SYSCALL_READ			(-4)
+#define XTENSA_SYSCALL_WRITE		(-5)
+#define XTENSA_SYSCALL_LSEEK		(-6)
+#define XTENSA_SYSCALL_RENAME		(-7)
+#define XTENSA_SYSCALL_UNLINK		(-8)
+#define XTENSA_SYSCALL_STAT			(-9)
+#define XTENSA_SYSCALL_FSTAT		(-10)
+#define XTENSA_SYSCALL_GETTIMEOFDAY	(-11)
+#define XTENSA_SYSCALL_ISATTY		(-12)
+#define XTENSA_SYSCALL_SYSTEM		(-13)
+
+int xtensa_fileio_init(struct target *target);
+int xtensa_fileio_detect_proc(struct target *target);
+int xtensa_get_gdb_fileio_info(struct target *target, struct gdb_fileio_info *fileio_info);
+int xtensa_gdb_fileio_end(struct target *target, int retcode, int fileio_errno, bool ctrl_c);
+
+#endif	/* OPENOCD_TARGET_XTENSA_FILEIO_H */