395 lines
12 KiB
C
395 lines
12 KiB
C
/****************************************************************************
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* drivers/efuse/efuse.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/types.h>
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#include <stdint.h>
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#include <stdbool.h>
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#include <string.h>
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#include <fcntl.h>
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#include <assert.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/irq.h>
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#include <nuttx/kmalloc.h>
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#include <nuttx/power/pm.h>
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#include <nuttx/semaphore.h>
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#include <nuttx/efuse/efuse.h>
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#ifdef CONFIG_EFUSE
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Type Definitions
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****************************************************************************/
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/* This structure describes the state of the upper half driver */
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struct efuse_upperhalf_s
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{
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sem_t exclsem; /* Supports mutual exclusion */
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FAR char *path; /* Registration path */
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/* The contained lower-half driver */
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FAR struct efuse_lowerhalf_s *lower;
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};
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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static int efuse_open(FAR struct file *filep);
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static int efuse_close(FAR struct file *filep);
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static ssize_t efuse_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen);
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static ssize_t efuse_write(FAR struct file *filep, FAR const char *buffer,
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size_t buflen);
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static int efuse_ioctl(FAR struct file *filep, int cmd,
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unsigned long arg);
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static const struct file_operations g_efuseops =
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{
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efuse_open, /* open */
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efuse_close, /* close */
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efuse_read, /* read */
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efuse_write, /* write */
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NULL, /* seek */
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efuse_ioctl, /* ioctl */
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NULL /* poll */
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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: efuse_open
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*
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* Description:
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* This function is called whenever the efuse timer device is opened.
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*
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****************************************************************************/
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static int efuse_open(FAR struct file *filep)
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{
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return OK;
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}
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/****************************************************************************
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* Name: efuse_close
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*
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* Description:
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* This function is called when the efuse timer device is closed.
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*
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****************************************************************************/
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static int efuse_close(FAR struct file *filep)
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{
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return OK;
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}
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/****************************************************************************
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* Name: efuse_read
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*
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* Description:
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* A dummy read method. This is provided only to satisfy the VFS layer.
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*
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****************************************************************************/
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static ssize_t efuse_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen)
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{
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/* Return zero -- usually meaning end-of-file */
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return 0;
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}
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/****************************************************************************
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* Name: efuse_write
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*
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* Description:
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* A dummy write method. This is provided only to satisfy the VFS layer.
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*
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****************************************************************************/
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static ssize_t efuse_write(FAR struct file *filep, FAR const char *buffer,
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size_t buflen)
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{
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return 0;
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}
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/****************************************************************************
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* Name: efuse_ioctl
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*
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* Description:
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* The standard ioctl method. This is where ALL of the efuse timer
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* work is done.
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*
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****************************************************************************/
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static int efuse_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct efuse_upperhalf_s *upper;
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FAR struct efuse_lowerhalf_s *lower;
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int ret;
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minfo("cmd: %d arg: %lu\n", cmd, arg);
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upper = inode->i_private;
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DEBUGASSERT(upper != NULL);
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lower = upper->lower;
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DEBUGASSERT(lower != NULL);
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/* Get exclusive access to the device structures */
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ret = nxsem_wait(&upper->exclsem);
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if (ret < 0)
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{
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return ret;
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}
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/* Handle built-in ioctl commands */
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switch (cmd)
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{
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/* cmd: EFUSEIOC_READ_FIELD
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* Description: Read a field
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* Argument: A pointer to a struct efuse_param.
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* Where the field is an array.
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* Each item in the array is a pointer to an efuse_desc_t
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* variable.
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* An efuse_desc_t variable contains an offset to a field
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* or subfield and its size in bits.
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* The size param is a redundancy, and it is the sum
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* of all subfields sizes from efuse_desc_t in bits.
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* The data is a pointer to a pre-allocated space
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* where the driver will load the data read from efuse.
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*/
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case EFUSEIOC_READ_FIELD:
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{
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FAR struct efuse_param *param =
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(FAR struct efuse_param *)((uintptr_t)arg);
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/* Read the efuse */
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DEBUGASSERT(lower->ops->read_field); /* Required */
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ret = lower->ops->read_field(lower,
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param->field,
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param->data,
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param->size);
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}
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break;
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/* cmd: EFUSEIOC_WRITE_FIELD
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* Description: Write a field
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* Argument: A pointer to a struct efuse_param.
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* Where the field is an array.
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* Each item in the array is a pointer to an efuse_desc_t
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* variable.
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* An efuse_desc_t variable contains an offset to a field
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* or subfield and its size in bits.
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* The size param is a redundancy, and it is the sum
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* of all subfields sizes from efuse_desc_t in bits.
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* The data is a pointer to a pre-allocated space
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* where the user wrote the value that he wants
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* to write in a field or subfield.
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*/
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case EFUSEIOC_WRITE_FIELD:
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{
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FAR struct efuse_param *param =
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(FAR struct efuse_param *)((uintptr_t)arg);
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/* Write the efuse */
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DEBUGASSERT(lower->ops->write_field); /* Required */
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ret = lower->ops->write_field(lower,
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param->field,
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param->data,
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param->size);
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}
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break;
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default:
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{
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minfo("Forwarding unrecognized cmd: %d arg: %lu\n", cmd, arg);
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/* Ioctls commands that are not recognized by the "upper-half"
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* driver are forwarded to the lower half driver through this
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* method.
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*/
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if (lower->ops->ioctl) /* Optional */
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{
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ret = lower->ops->ioctl(lower, cmd, arg);
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}
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else
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{
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ret = -ENOTTY;
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}
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}
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break;
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}
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nxsem_post(&upper->exclsem);
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return ret;
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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: efuse_register
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*
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* Description:
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* This function binds an instance of a "lower half" efuse driver with
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* the "upper half" efuse device and registers that device so that can
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* be used by application code.
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*
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* Input Parameters:
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* dev path - The full path to the driver to be registered in the NuttX
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* pseudo-filesystem. The recommended convention is to name all
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* efuse drivers as "/dev/efuse".
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* lower - A pointer to an instance of lower half efuse driver. This
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* instance is bound to the efuse driver and must persists as long as
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* the driver persists.
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*
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* Returned Value:
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* On success, a non-NULL handle is returned to the caller. In the event
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* of any failure, a NULL value is returned.
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*
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****************************************************************************/
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FAR void *efuse_register(FAR const char *path,
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FAR struct efuse_lowerhalf_s *lower)
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{
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FAR struct efuse_upperhalf_s *upper;
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int ret;
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DEBUGASSERT(path && lower);
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minfo("Entry: path=%s\n", path);
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/* Allocate the upper-half data structure */
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upper = (FAR struct efuse_upperhalf_s *)
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kmm_zalloc(sizeof(struct efuse_upperhalf_s));
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if (!upper)
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{
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merr("Upper half allocation failed\n");
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goto errout;
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}
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/* Initialize the efuse timer device structure (it was already zeroed
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* by kmm_zalloc()).
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*/
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nxsem_init(&upper->exclsem, 0, 1);
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upper->lower = lower;
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/* Copy the registration path */
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upper->path = strdup(path);
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if (!upper->path)
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{
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merr("Path allocation failed\n");
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goto errout_with_upper;
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}
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/* Register the efuse timer device */
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ret = register_driver(path, &g_efuseops, 0666, upper);
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if (ret < 0)
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{
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merr("register_driver failed: %d\n", ret);
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goto errout_with_path;
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}
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return (FAR void *)upper;
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errout_with_path:
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kmm_free(upper->path);
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errout_with_upper:
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nxsem_destroy(&upper->exclsem);
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kmm_free(upper);
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errout:
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return NULL;
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}
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/****************************************************************************
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* Name: efuse_unregister
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*
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* Description:
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* This function can be called to disable and unregister the efuse
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* device driver.
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*
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* Input Parameters:
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* handle - This is the handle that was returned by efuse_register()
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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void efuse_unregister(FAR void *handle)
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{
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FAR struct efuse_upperhalf_s *upper;
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FAR struct efuse_lowerhalf_s *lower;
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/* Recover the pointer to the upper-half driver state */
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upper = (FAR struct efuse_upperhalf_s *)handle;
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DEBUGASSERT(upper != NULL);
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lower = upper->lower;
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DEBUGASSERT(lower != NULL);
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minfo("Unregistering: %s\n", upper->path);
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/* Unregister the efuse timer device */
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unregister_driver(upper->path);
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/* Then free all of the driver resources */
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kmm_free(upper->path);
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nxsem_destroy(&upper->exclsem);
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kmm_free(upper);
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}
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#endif /* CONFIG_EFUSE */
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