OVMS3-idf/components/vfs/vfs_semihost.c

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2019-02-19 19:50:18 +00:00
// Copyright 2019 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <string.h>
#include <stdbool.h>
#include <stdarg.h>
#include <sys/errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "soc/cpu.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_vfs.h"
#define LOG_LOCAL_LEVEL ESP_LOG_NONE
#include "esp_log.h"
const static char *TAG = "esp_semihost";
#define SYSCALL_INSTR "break 1,1\n"
#define SYS_OPEN 0x01
#define SYS_CLOSE 0x02
#define SYS_WRITE 0x05
#define SYS_READ 0x06
#define SYS_SEEK 0x0A
/** ESP-specific file open flag. Indicates that path passed to open() is absolute host path. */
#define ESP_O_SEMIHOST_ABSPATH 0x80000000
typedef struct {
char base_path[ESP_VFS_PATH_MAX+1]; /* base path in VFS where host semohosting dir is mounted */
char host_path[CONFIG_SEMIHOSTFS_HOST_PATH_MAX_LEN+1]; /* host path to use as base dir for open files */
} vfs_semihost_ctx_t;
static vfs_semihost_ctx_t s_semhost_ctx[CONFIG_SEMIHOSTFS_MAX_MOUNT_POINTS];
static inline int generic_syscall(int sys_nr, int arg1, int arg2, int arg3, int arg4, int* ret_errno)
{
int host_ret, host_errno;
if (!esp_cpu_in_ocd_debug_mode()) {
*ret_errno = EIO;
return -1;
}
__asm__ volatile (
"mov a2, %[sys_nr]\n" \
"mov a3, %[arg1]\n" \
"mov a4, %[arg2]\n" \
"mov a5, %[arg3]\n" \
"mov a6, %[arg4]\n" \
SYSCALL_INSTR \
"mov %[host_ret], a2\n" \
"mov %[host_errno], a3\n" \
:[host_ret]"=r"(host_ret),[host_errno]"=r"(host_errno)
:[sys_nr]"r"(sys_nr),[arg1]"r"(arg1),[arg2]"r"(arg2),[arg3]"r"(arg3),[arg4]"r"(arg4)
:"a2","a3","a4","a5","a6");
*ret_errno = host_errno;
return host_ret;
}
inline bool ctx_is_unused(const vfs_semihost_ctx_t* ctx)
{
return ctx->base_path[0] == 0;
}
inline bool ctx_uses_abspath(const vfs_semihost_ctx_t* ctx)
{
return ctx->host_path[0];
}
static int vfs_semihost_open(void* ctx, const char * path, int flags, int mode)
{
int fd = -1, host_err = 0;
char *host_path;
vfs_semihost_ctx_t *semi_ctx = ctx;
ESP_LOGV(TAG, "%s: %p '%s 0x%x 0x%x'", __func__, semi_ctx, path, flags, mode);
if (ctx_uses_abspath(semi_ctx)) {
flags |= ESP_O_SEMIHOST_ABSPATH;
host_path = malloc(strlen(semi_ctx->host_path)+strlen(path)+1);
if(host_path == NULL) {
errno = ENOMEM;
return -1;
}
strcpy(host_path, semi_ctx->host_path);
strcat(host_path, path);
} else {
host_path = (char *)path;
}
fd = generic_syscall(SYS_OPEN, (int)host_path, strlen(host_path), flags, mode, &host_err);
if (ctx_uses_abspath(semi_ctx)) {
free(host_path);
}
if (fd == -1) {
errno = host_err;
}
return fd;
}
static ssize_t vfs_semihost_write(void* ctx, int fd, const void * data, size_t size)
{
int host_err = 0;
size_t ret = -1;
ESP_LOGV(TAG, "%s: %d %u bytes", __func__, fd, size);
ret = generic_syscall(SYS_WRITE, fd, (int)data, size, 0, &host_err);
if (ret == -1) {
errno = host_err;
}
return (ssize_t)ret;
}
static ssize_t vfs_semihost_read(void* ctx, int fd, void* data, size_t size)
{
int host_err = 0;
size_t ret = -1;
ESP_LOGV(TAG, "%s: %d %u bytes", __func__, fd, size);
ret = generic_syscall(SYS_READ, fd, (int)data, size, 0, &host_err);
if (ret == -1) {
errno = host_err;
}
return (ssize_t)ret;
}
static int vfs_semihost_close(void* ctx, int fd)
{
int ret = -1, host_err = 0;
ESP_LOGV(TAG, "%s: %d", __func__, fd);
ret = generic_syscall(SYS_CLOSE, fd, 0, 0, 0, &host_err);
if (ret == -1) {
errno = host_err;
}
return ret;
}
static off_t vfs_semihost_lseek(void* ctx, int fd, off_t size, int mode)
{
int ret = -1, host_err = 0;
ESP_LOGV(TAG, "%s: %d %ld %d", __func__, fd, size, mode);
ret = generic_syscall(SYS_SEEK, fd, size, mode, 0, &host_err);
if (ret == -1) {
errno = host_err;
}
return (off_t)ret;
}
esp_err_t esp_vfs_semihost_register(const char* base_path, const char* host_path)
{
const esp_vfs_t vfs = {
.flags = ESP_VFS_FLAG_CONTEXT_PTR,
.write_p = &vfs_semihost_write,
.open_p = &vfs_semihost_open,
.close_p = &vfs_semihost_close,
.read_p = &vfs_semihost_read,
.lseek_p = &vfs_semihost_lseek,
};
ESP_LOGD(TAG, "Register semihosting driver '%s' -> '%s'", base_path, host_path ? host_path : "null");
if (!esp_cpu_in_ocd_debug_mode()) {
ESP_LOGE(TAG, "OpenOCD is not connected!");
return ESP_ERR_NOT_SUPPORTED;
}
int i = 0;
for (i = 0; i < CONFIG_SEMIHOSTFS_MAX_MOUNT_POINTS; i++) {
if (ctx_is_unused(&s_semhost_ctx[i])) {
break;
}
if (strcmp(base_path, s_semhost_ctx[i].base_path) == 0) {
return ESP_ERR_INVALID_STATE;
}
}
if (i == CONFIG_SEMIHOSTFS_MAX_MOUNT_POINTS) {
return ESP_ERR_NO_MEM;
}
strlcpy(s_semhost_ctx[i].base_path, base_path, sizeof(s_semhost_ctx[i].base_path) - 1);
if (host_path) {
strlcpy(s_semhost_ctx[i].host_path, host_path, sizeof(s_semhost_ctx[i].host_path) - 1);
}
ESP_LOGD(TAG, "Register semihosting driver %d %p", i, &s_semhost_ctx[i]);
return esp_vfs_register(base_path, &vfs, &s_semhost_ctx[i]);
}
esp_err_t esp_vfs_semihost_unregister(const char* base_path)
{
ESP_LOGD(TAG, "Unregister semihosting driver @ '%s'", base_path);
int i = 0;
for (i = 0; i < CONFIG_SEMIHOSTFS_MAX_MOUNT_POINTS; i++) {
if (s_semhost_ctx[i].base_path[0] != 0 && strcmp(base_path, s_semhost_ctx[i].base_path) == 0) {
break;
}
}
if (i == CONFIG_SEMIHOSTFS_MAX_MOUNT_POINTS) {
return ESP_ERR_INVALID_ARG;
}
esp_err_t ret = esp_vfs_unregister(s_semhost_ctx[i].base_path);
if (ret != ESP_OK) {
return ret;
}
s_semhost_ctx[i].base_path[0] = 0;
s_semhost_ctx[i].host_path[0] = 0;
ESP_LOGD(TAG, "Unregistered semihosting driver @ '%s'", base_path);
return ESP_OK;
}