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Permissions (Part 2) Description: In kernel builds, any unprivileged process running on the NuttX device can open /dev/efuse and attempt to read/write fuse content. Reading the fuses may provide valuable information to an attacker controlling the user process. The write operation, in extreme cases where the fuse blocks are not locked, may brick the device. DISCLAIMER: I tried to be strict with the settings, better to relax them later if it's needed. This is part of https://github.com/apache/nuttx/issues/19410 See https://github.com/apache/nuttx/issues/19410 Compiles ok. Signed-off-by: Catalin Visinescu <catalin_visinescu@yahoo.com>
349 lines
11 KiB
C
349 lines
11 KiB
C
/****************************************************************************
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* drivers/sensors/max31865.c
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*
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* SPDX-License-Identifier: Apache-2.0
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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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/* WARNING for developers:
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*
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* This driver uses the legacy style of writing sensor drivers for NuttX. The
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* project has since decided to adopt a new sensor framework in order to
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* have a consistent API and feature-set.
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*
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* Sensors which use the uORB framework are typically suffixed "_uorb". You
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* can also visit the documentation about the new sensor framework to learn
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* more.
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*/
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#warning "This is a deprecated legacy sensor driver."
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/* Character driver for the Maxim MAX31865 Thermocouple-to-Digital Converter
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*
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* NOTE: Some Maxim MAX31865 chips have an issue it report value 25% lower
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* of real temperature, for more info read this thread:
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* http://www.eevblog.com/forum/projects/max31865-temperature-error/
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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 <inttypes.h>
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#include <stdlib.h>
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#include <fixedmath.h>
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#include <assert.h>
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#include <errno.h>
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#include <nuttx/debug.h>
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#include <math.h>
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#include <nuttx/kmalloc.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/spi/spi.h>
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#include <nuttx/sensors/max31865.h>
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#include <nuttx/random.h>
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#include <sys/endian.h>
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#if defined(CONFIG_SPI) && defined(CONFIG_SENSORS_MAX31865)
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#define MAX31865_CONFIG_REG 0x00
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# define MAX31865_BIAS_ON (1 << 7)
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# define MAX31865_AUTO_CONVERSION (1 << 6)
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# define MAX31865_ONE_SHOT (1 << 5)
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# define MAX31865_3WIRE (1 << 4)
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# define MAX31865_FAULT_DET_OFFSET (2)
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# define MAX31865_FAULT_DET_MASK (3 << MAX31865_FAULT_DET_OFFSET)
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# define MAX31865_FAULT_DET_OFF (0 << MAX31865_FAULT_DET_OFFSET)
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# define MAX31865_FAULT_DET_AUTO (1 << MAX31865_FAULT_DET_OFFSET)
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# define MAX31865_FAULT_DET_1CYCLE (2 << MAX31865_FAULT_DET_OFFSET)
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# define MAX31865_FAULT_DET_2CYCLE (3 << MAX31865_FAULT_DET_OFFSET)
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# define MAX31865_FAULT_STATUS_CLR (1 << 1)
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# define MAX31865_50HZ_FILTER (1 << 0)
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#define MAX31865_RTDMSB_REG 0x01
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#define MAX31865_RTDLSB_REG 0x02
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#define MAX31865_HFAULTMSB_REG 0x03
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#define MAX31865_HFAULTLSB_REG 0x04
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#define MAX31865_LFAULTMSB_REG 0x05
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#define MAX31865_LFAULTLSB_REG 0x06
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#define MAX31865_FAULTSTAT_REG 0x07
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#define MAX31865_REF_RESISTOR 430
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#define MAX31865_WRITE 0x80
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#define RTD_A (3.9083e-3)
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#define RTD_B (-5.775e-7)
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/****************************************************************************
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* Private Types
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****************************************************************************/
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struct max31865_dev_s
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{
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FAR struct spi_dev_s *spi; /* Saved SPI driver instance */
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int16_t temp;
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uint16_t devid; /* Select minor device number */
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};
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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static void max31865_lock(FAR struct spi_dev_s *spi);
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static void max31865_unlock(FAR struct spi_dev_s *spi);
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/* Character driver methods */
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static int max31865_open(FAR struct file *filep);
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static ssize_t max31865_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen);
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static ssize_t max31865_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_max31865fops =
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{
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max31865_open, /* open */
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NULL, /* close */
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max31865_read, /* read */
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max31865_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: max31865_lock
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*
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* Description:
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* Lock and configure the SPI bus.
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*
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****************************************************************************/
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static void max31865_lock(FAR struct spi_dev_s *spi)
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{
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SPI_LOCK(spi, true);
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SPI_SETMODE(spi, SPIDEV_MODE1);
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SPI_SETBITS(spi, 8);
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SPI_HWFEATURES(spi, 0);
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SPI_SETFREQUENCY(spi, 400000);
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}
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/****************************************************************************
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* Name: max31865_unlock
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*
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* Description:
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* Unlock the SPI bus.
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*
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****************************************************************************/
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static void max31865_unlock(FAR struct spi_dev_s *spi)
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{
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SPI_LOCK(spi, false);
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}
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/****************************************************************************
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* Name: max31865_open
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*
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* Description:
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* This function is called whenever the MAX31865 device is opened.
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*
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****************************************************************************/
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static int max31865_open(FAR struct file *filep)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct max31865_dev_s *priv = inode->i_private;
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unsigned char regval;
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/* Enable MAX31865's chip select */
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max31865_lock(priv->spi);
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SPI_SELECT(priv->spi, SPIDEV_TEMPERATURE(priv->devid), true);
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regval = MAX31865_WRITE | MAX31865_CONFIG_REG;
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SPI_SEND(priv->spi, regval);
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regval = MAX31865_50HZ_FILTER | MAX31865_3WIRE | \
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MAX31865_AUTO_CONVERSION | MAX31865_BIAS_ON;
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SPI_SEND(priv->spi, regval);
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/* Disable MAX31865's chip select */
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SPI_SELECT(priv->spi, SPIDEV_TEMPERATURE(priv->devid), false);
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max31865_unlock(priv->spi);
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return OK;
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}
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/****************************************************************************
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* Name: max31865_read
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****************************************************************************/
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static ssize_t max31865_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct max31865_dev_s *priv = inode->i_private;
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uint8_t regval[8];
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float temp;
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uint16_t regmsb;
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float rt;
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/* Check for issues */
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if (!buffer)
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{
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snerr("ERROR: Buffer is null\n");
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return -EINVAL;
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}
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if (buflen != sizeof(float))
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{
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snerr("ERROR: You can't read something other than 16 bits "
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"(2 bytes)\n");
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return -EINVAL;
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}
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/* Enable MAX31865's chip select */
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max31865_lock(priv->spi);
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SPI_SELECT(priv->spi, SPIDEV_TEMPERATURE(priv->devid), true);
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/* Read temperature */
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memset(regval, 0, sizeof(regval));
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SPI_SEND(priv->spi, MAX31865_CONFIG_REG);
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SPI_RECVBLOCK(priv->spi, regval, sizeof(regval));
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/* Disable MAX31865's chip select */
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SPI_SELECT(priv->spi, SPIDEV_TEMPERATURE(priv->devid), false);
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max31865_unlock(priv->spi);
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/* Detect any errors during SPI transmission */
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if (*regval != (MAX31865_50HZ_FILTER | MAX31865_3WIRE | \
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MAX31865_AUTO_CONVERSION | MAX31865_BIAS_ON))
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{
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snerr("ERROR: Data transmission failed on device %d:\n", priv->devid);
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snerr(" One or more MAX31865 pins are not properly connected!\n\n");
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return -EINVAL;
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}
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/* Resistance of the RTD */
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regmsb = ((regval[1] << 8) | regval[2]) >> 1;
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rt = (float)(regmsb * MAX31865_REF_RESISTOR / 32768.0);
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/* T = (-A + sqrt(A^2 - 4*B*(1 - R/R0))) / (2*B) */
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temp = (-RTD_A + sqrt(RTD_A * RTD_A - 4 * RTD_B * (1 - rt / 100.0))) \
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/ (2 * RTD_B);
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*(FAR float *)buffer = temp;
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sninfo("MAX31865 ADC: %d, RTD: %.2f, temperature: %.1f\n", \
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regmsb, rt, temp);
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return sizeof(temp);
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}
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/****************************************************************************
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* Name: max31865_write
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****************************************************************************/
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static ssize_t max31865_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 -ENOSYS;
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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: max31865_register
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*
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* Description:
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* This function will register the max31865 driver as /dev/tempN
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* where N is the minor device number
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*
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* Input Parameters:
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* devpath - The full path to the driver to register. E.g., "/dev/temp0"
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* spi - An instance of the SPI interface to use to communicate with
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* MAX31865
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* devid - Minor device number. E.g., 0, 1, 2, etc.
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*
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* Returned Value:
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* Zero is returned on success. Otherwise, a negated errno value is
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* returned to indicate the nature of the failure.
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*
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****************************************************************************/
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int max31865_register(FAR const char *devpath, FAR struct spi_dev_s *spi,
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uint16_t devid)
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{
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FAR struct max31865_dev_s *priv;
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int ret;
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/* Sanity check */
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DEBUGASSERT(spi != NULL);
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/* Initialize the MAX31865 device structure */
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priv = (FAR struct max31865_dev_s *)
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kmm_malloc(sizeof(struct max31865_dev_s));
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if (priv == NULL)
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{
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snerr("ERROR: Failed to allocate instance\n");
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return -ENOMEM;
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}
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priv->spi = spi;
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priv->temp = 0;
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priv->devid = devid;
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/* Register the character driver */
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ret = register_driver(devpath, &g_max31865fops, 0600, priv);
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if (ret < 0)
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{
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snerr("ERROR: Failed to register driver: %d\n", ret);
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kmm_free(priv);
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}
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return ret;
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}
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#endif /* CONFIG_SPI && CONFIG_SENSORS_MAX31865 */
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