vfs: add support for semihosting on ESP32-C3

components/vfs/openocd_semihosting.h

@@ -0,0 +1,150 @@
+/*
+ * SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#pragma once
+
+#include <string.h>
+#include <sys/errno.h>
+
+#ifdef __XTENSA__
+#include "xtensa/semihosting.h"
+#elif __riscv
+#include "riscv/semihosting.h"
+#else
+#error Unsupported architecture
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Semihosting call numbers and functions for OpenOCD.
+ * In OpenOCD, ARM semihosting call numbers and parameters are used for
+ * RISC-V and Xtensa targets.
+ *
+ * These conventions are not compatible with Xtensa ISS and QEMU for Xtensa,
+ * which the actual Xtensa-specific semihosting call numbers and formats;
+ * these are not supported in ESP-IDF yet.
+ */
+
+#define SEMIHOSTING_SYS_CLOCK 0x10
+#define SEMIHOSTING_SYS_CLOSE 0x02
+#define SEMIHOSTING_SYS_ERRNO 0x13
+#define SEMIHOSTING_SYS_EXIT 0x18
+#define SEMIHOSTING_SYS_EXIT_EXTENDED 0x20
+#define SEMIHOSTING_SYS_FLEN 0x0C
+#define SEMIHOSTING_SYS_GET_CMDLINE 0x15
+#define SEMIHOSTING_SYS_HEAPINFO 0x16
+#define SEMIHOSTING_SYS_ISERROR 0x08
+#define SEMIHOSTING_SYS_ISTTY 0x09
+#define SEMIHOSTING_SYS_OPEN 0x01
+#define SEMIHOSTING_SYS_READ 0x06
+#define SEMIHOSTING_SYS_READC 0x07
+#define SEMIHOSTING_SYS_REMOVE 0x0E
+#define SEMIHOSTING_SYS_RENAME 0x0F
+#define SEMIHOSTING_SYS_SEEK 0x0A
+#define SEMIHOSTING_SYS_SYSTEM 0x12
+#define SEMIHOSTING_SYS_TIME 0x11
+#define SEMIHOSTING_SYS_WRITE 0x05
+#define SEMIHOSTING_SYS_WRITEC 0x03
+#define SEMIHOSTING_SYS_WRITE0 0x04
+
+/* This call is an Espressif OpenOCD extension to send the version
+ * information to the host. This lets the host support different IDF versions,
+ * allowing semihosting interface to be modified over time.
+ *
+ * The parameters of this call are:
+ * - pointer to the version info structure,
+ * - size of the version info structure.
+ *
+ * At present, the structure should contain a single word, indicating
+ * the semihosting interface version used by the target.
+ *
+ * If the syscall is recognized, the return value is zero.
+ */
+#define SEMIHOSTING_SYS_DRVINFO 0xE0
+
+
+static inline int semihosting_open(const char *path, int open_mode, int mode)
+{
+    int host_errno = 0;
+    long args[] = {(long) path, open_mode, strlen(path), 0};
+    (void) mode;  // unused in OpenOCD
+    int result = (int) semihosting_call(SEMIHOSTING_SYS_OPEN, args, &host_errno);
+    if (result < 0) {
+        errno = host_errno;
+    }
+    return result;
+}
+
+static inline ssize_t semihosting_write(int fd, const void *data, size_t size)
+{
+    int host_errno = 0;
+    long args[] = {fd, (long) data, size, 0};
+    ssize_t ret = (ssize_t) semihosting_call(SEMIHOSTING_SYS_WRITE, args, &host_errno);
+    if (ret < 0) {
+        errno = host_errno;
+        return ret;
+    }
+    /* On success, write syscall returns the number of bytes NOT written,
+     * adjust the return value to match POSIX.
+     */
+    return size - (ssize_t)ret;
+}
+
+static inline ssize_t semihosting_read(int fd, void *data, size_t size)
+{
+    int host_errno = 0;
+    long args[] = {fd, (long) data, size, 0};
+    ssize_t ret = (ssize_t) semihosting_call(SEMIHOSTING_SYS_READ, args, &host_errno);
+    if (ret < 0) {
+        errno = host_errno;
+        return ret;
+    }
+    /* On success, read syscall returns the number of bytes NOT read,
+     * adjust the return value to match POSIX.
+     */
+    return size - (ssize_t)ret;
+}
+
+static inline int semihosting_close(int fd)
+{
+    int host_errno = 0;
+    long args[] = {fd, 0, 0, 0};
+    int ret = (int) semihosting_call(SEMIHOSTING_SYS_CLOSE, args, &host_errno);
+    if (ret < 0) {
+        errno = host_errno;
+    }
+    return ret;
+}
+
+static inline off_t semihosting_seek(int fd, off_t offset, int mode)
+{
+    int host_errno = 0;
+    long args[] = {fd, offset, mode, 0};
+    off_t ret = (off_t) semihosting_call(SEMIHOSTING_SYS_SEEK, args, &host_errno);
+    if (ret == -1) {
+        errno = host_errno;
+    }
+    return ret;
+}
+
+static inline int semihosting_ver_info(void)
+{
+    int host_errno = 0;
+    struct {
+        int version;
+    } ver_info = { 1 };
+    long args[] = {(long) &ver_info, sizeof(ver_info), 0, 0};
+    int ret = (int) semihosting_call(SEMIHOSTING_SYS_DRVINFO, args, &host_errno);
+    (void) host_errno;  /* errno not set by this call */
+    return ret;
+}
+
+#ifdef __cplusplus
+}
+#endif