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a3a1c160ee
Returning the number of bytes written/read could return a negative integer because a uint32_t is expected for the length in read()/write() operations.
140 lines
3.3 KiB
C
140 lines
3.3 KiB
C
/*
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* Copyright (C) 2016 Eistec AB
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*
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* This file is subject to the terms and conditions of the GNU Lesser General
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* Public License v2.1. See the file LICENSE in the top level directory for more
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* details.
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*/
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#if MODULE_VFS
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#include <fcntl.h>
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#include <errno.h>
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#include <unistd.h>
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#include "mtd.h"
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#include "vfs.h"
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/**
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* @ingroup drivers_mtd
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* @{
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*
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* @file
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*
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* @brief MTD generic VFS operations
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*
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* This allows the MTD driver to register as a node on DevFS
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*
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* See boards/mulle or tests/unittests/tests-devfs for examples on how to use.
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*
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* Tested with mtd_spi_nor on Mulle
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*
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* @author Joakim Nohlgård <joakim.nohlgard@eistec.se>
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*/
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static int mtd_vfs_fstat(vfs_file_t *filp, struct stat *buf);
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static off_t mtd_vfs_lseek(vfs_file_t *filp, off_t off, int whence);
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static ssize_t mtd_vfs_read(vfs_file_t *filp, void *dest, size_t nbytes);
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static ssize_t mtd_vfs_write(vfs_file_t *filp, const void *src, size_t nbytes);
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const vfs_file_ops_t mtd_vfs_ops = {
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.fstat = mtd_vfs_fstat,
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.lseek = mtd_vfs_lseek,
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.read = mtd_vfs_read,
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.write = mtd_vfs_write,
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};
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static int mtd_vfs_fstat(vfs_file_t *filp, struct stat *buf)
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{
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if (buf == NULL) {
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return -EFAULT;
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}
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const mtd_dev_t *mtd = filp->private_data.ptr;
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if (mtd == NULL) {
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return -EFAULT;
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}
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buf->st_nlink = 1;
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buf->st_size = mtd->page_size * mtd->sector_count * mtd->pages_per_sector;
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return 0;
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}
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static off_t mtd_vfs_lseek(vfs_file_t *filp, off_t off, int whence)
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{
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const mtd_dev_t *mtd = filp->private_data.ptr;
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if (mtd == NULL) {
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return -EFAULT;
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}
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switch (whence) {
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case SEEK_SET:
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break;
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case SEEK_CUR:
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off += filp->pos;
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break;
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case SEEK_END:
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off += mtd->page_size * mtd->sector_count * mtd->pages_per_sector;
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break;
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default:
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return -EINVAL;
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}
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if (off < 0) {
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/* the resulting file offset would be negative */
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return -EINVAL;
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}
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/* POSIX allows seeking past the end of the file */
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filp->pos = off;
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return off;
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}
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static ssize_t mtd_vfs_read(vfs_file_t *filp, void *dest, size_t nbytes)
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{
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mtd_dev_t *mtd = filp->private_data.ptr;
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if (mtd == NULL) {
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return -EFAULT;
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}
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uint32_t size = mtd->page_size * mtd->sector_count * mtd->pages_per_sector;
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uint32_t src = filp->pos;
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if (src >= size) {
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return 0;
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}
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if ((src + nbytes) > size) {
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nbytes = size - src;
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}
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int res = mtd_read(mtd, dest, src, nbytes);
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if (res != 0) {
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return -EIO;
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}
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/* Advance file position */
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filp->pos += nbytes;
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return nbytes;
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}
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static ssize_t mtd_vfs_write(vfs_file_t *filp, const void *src, size_t nbytes)
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{
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mtd_dev_t *mtd = filp->private_data.ptr;
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if (mtd == NULL) {
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return -EFAULT;
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}
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uint32_t size = mtd->page_size * mtd->sector_count * mtd->pages_per_sector;
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uint32_t dest = filp->pos;
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if (dest >= size) {
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/* attempt to write outside the device memory */
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return -ENOSPC;
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}
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if ((dest + nbytes) > size) {
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nbytes = size - dest;
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}
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int res = mtd_write(mtd, src, dest, nbytes);
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if (res != 0) {
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return -EIO;
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}
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/* Advance file position */
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filp->pos += nbytes;
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return nbytes;
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}
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/** @} */
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#else
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typedef int dont_be_pedantic;
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#endif /* MODULE_VFS */
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