135 lines
4.7 KiB
C
135 lines
4.7 KiB
C
/****************************************************************************
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* apps/examples/module/drivers/chardev/chardev.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/param.h>
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#include <sys/types.h>
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#include <stdbool.h>
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#include <string.h>
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#include <errno.h>
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#include <syslog.h>
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#include <debug.h>
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#include <nuttx/module.h>
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#include <nuttx/lib/modlib.h>
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#include <nuttx/fs/fs.h>
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/****************************************************************************
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* Private data
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****************************************************************************/
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static const char g_read_string[] = "Hi there, apps/examples/module test\n";
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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static ssize_t chardev_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen);
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static ssize_t chardev_write(FAR struct file *filep, FAR const char *buffer,
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size_t buflen);
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static const struct file_operations g_chardev_fops =
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{
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NULL, /* open */
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NULL, /* close */
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chardev_read, /* read */
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chardev_write, /* write */
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: chardev_read
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****************************************************************************/
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static ssize_t chardev_read(FAR struct file *filep, FAR char *buffer,
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size_t len)
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{
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size_t rdlen = strlen(g_read_string);
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ssize_t ret = MIN(len, rdlen);
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memcpy(buffer, g_read_string, ret);
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syslog(LOG_INFO, "chardev_read: Returning %d bytes\n", (int)ret);
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lib_dumpbuffer("chardev_read: Returning",
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(FAR const uint8_t *)buffer, ret);
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return ret;
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}
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/****************************************************************************
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* Name: chardev_write
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****************************************************************************/
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static ssize_t chardev_write(FAR struct file *filep, FAR const char *buffer,
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size_t len)
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{
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syslog(LOG_INFO, "chardev_write: Writing %d bytes\n", (int)len);
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lib_dumpbuffer("chardev_write: Writing", (FAR const uint8_t *)buffer, len);
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return len;
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}
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/****************************************************************************
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* Name: module_uninitialize
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****************************************************************************/
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static int module_uninitialize(FAR void *arg)
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{
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/* TODO: Check if there are any open references to the driver */
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syslog(LOG_INFO, "module_uninitialize: arg=%p\n", arg);
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return unregister_driver("/dev/chardev");
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: module_initialize
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*
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* Description:
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* Register /dev/chardev
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*
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****************************************************************************/
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int module_initialize(FAR struct mod_info_s *modinfo)
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{
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syslog(LOG_INFO, "module_initialize:\n");
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modinfo->uninitializer = module_uninitialize;
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modinfo->arg = NULL;
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modinfo->exports = NULL;
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modinfo->nexports = 0;
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return register_driver("/dev/chardev", &g_chardev_fops, 0666, NULL);
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}
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