761ee81956
currently, nuttx implements readv/writev on the top of read/write. while it might work for the simplest cases, it's broken by design. for example, it's impossible to make it work correctly for files which need to preserve data boundaries without allocating a single contiguous buffer. (udp socket, some character devices, etc) this change is a start of the migration to a better design. that is, implement read/write on the top of readv/writev. to avoid a single huge change, following things will NOT be done in this commit: * fix actual bugs caused by the original readv-based-on-read design. (cf. https://github.com/apache/nuttx/pull/12674) * adapt filesystems/drivers to actually benefit from the new interface. (except a few trivial examples) * eventually retire the old interface. * retire read/write syscalls. implement them in libc instead. * pread/pwrite/preadv/pwritev (except the introduction of struct uio, which is a preparation to back these variations with the new interface.)
400 lines
11 KiB
C
400 lines
11 KiB
C
/****************************************************************************
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* drivers/i3c/i3c_driver.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 <stdbool.h>
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#include <stdio.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/kmalloc.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/mutex.h>
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#include <nuttx/i3c/master.h>
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#include <nuttx/i3c/i3c_driver.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#define DEVNAME_FMT "/dev/i3c%d"
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#define DEVNAME_FMTLEN (8 + 3 + 1)
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/****************************************************************************
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* Private Types
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****************************************************************************/
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/* Driver state structure */
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struct i3c_driver_s
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{
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/* Contained I3C lower half driver */
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FAR struct i3c_master_controller *master;
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/* Mutual exclusion */
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mutex_t lock;
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/* Number of open references */
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int16_t crefs;
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/* True, driver has been unlinked */
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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bool unlinked;
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#endif
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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 i3cdrvr_open(FAR struct file *filep);
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static int i3cdrvr_close(FAR struct file *filep);
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static ssize_t i3cdrvr_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen);
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static ssize_t i3cdrvr_write(FAR struct file *filep, FAR const char *buffer,
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size_t buflen);
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static int i3cdrvr_ioctl(FAR struct file *filep, int cmd,
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unsigned long arg);
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static int i3cdrvr_unlink(FAR struct inode *inode);
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static const struct file_operations g_i3cdrvr_fops =
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{
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i3cdrvr_open, /* open */
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i3cdrvr_close, /* close */
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i3cdrvr_read, /* read */
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i3cdrvr_write, /* write */
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NULL, /* seek */
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i3cdrvr_ioctl, /* ioctl */
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NULL, /* mmap */
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NULL, /* truncate */
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NULL, /* poll */
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NULL, /* readv */
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NULL /* writev */
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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, i3cdrvr_unlink /* unlink */
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#endif
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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: i3cdrvr_open
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****************************************************************************/
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static int i3cdrvr_open(FAR struct file *filep)
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{
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FAR struct inode *inode;
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FAR struct i3c_driver_s *priv;
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int ret;
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DEBUGASSERT(filep != NULL && filep->f_inode != NULL);
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inode = filep->f_inode;
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priv = inode->i_private;
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DEBUGASSERT(priv);
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/* Get exclusive access to the I3C driver state structure */
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ret = nxmutex_lock(&priv->lock);
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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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/* Increment the count of open references on the driver */
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priv->crefs++;
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DEBUGASSERT(priv->crefs > 0);
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nxmutex_unlock(&priv->lock);
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return OK;
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}
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/****************************************************************************
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* Name: i3cdrvr_close
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****************************************************************************/
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static int i3cdrvr_close(FAR struct file *filep)
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{
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FAR struct inode *inode;
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FAR struct i3c_driver_s *priv;
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int ret;
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/* Get our private data structure */
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DEBUGASSERT(filep != NULL && filep->f_inode != NULL);
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inode = filep->f_inode;
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priv = inode->i_private;
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DEBUGASSERT(priv);
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/* Get exclusive access to the I3C driver state structure */
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ret = nxmutex_lock(&priv->lock);
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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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/* Decrement the count of open references on the driver */
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DEBUGASSERT(priv->crefs > 0);
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priv->crefs--;
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/* If the count has decremented to zero,then commit Hara-Kiri now. */
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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if (priv->crefs <= 0 && priv->unlinked)
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#else
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if (priv->crefs <= 0)
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#endif
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{
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nxmutex_destroy(&priv->lock);
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kmm_free(priv);
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return OK;
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}
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nxmutex_unlock(&priv->lock);
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return OK;
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}
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/****************************************************************************
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* Name: i3cdrvr_read
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****************************************************************************/
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static ssize_t i3cdrvr_read(FAR struct file *filep, FAR char *buffer,
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size_t len)
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{
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return 0; /* Return EOF */
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}
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/****************************************************************************
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* Name: i3cdrvr_write
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****************************************************************************/
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static ssize_t i3cdrvr_write(FAR struct file *filep, FAR const char *buffer,
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size_t len)
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{
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return len; /* Say that everything was written */
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}
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/****************************************************************************
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* Name: i3cdrvr_ioctl
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****************************************************************************/
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static int i3cdrvr_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
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{
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FAR struct inode *inode;
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FAR struct i3c_driver_s *priv;
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FAR struct i3c_transfer_s *transfer;
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FAR struct i3c_dev_desc *desc;
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bool obtain = false;
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uint16_t manufid;
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uint16_t partid;
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int ret;
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DEBUGASSERT(filep != NULL && filep->f_inode != NULL);
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inode = filep->f_inode;
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priv = inode->i_private;
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DEBUGASSERT(priv);
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/* Get exclusive access to the I3C driver state structure */
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ret = nxmutex_lock(&priv->lock);
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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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transfer = (FAR struct i3c_transfer_s *)((uintptr_t)arg);
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DEBUGASSERT(transfer != NULL);
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i3c_bus_normaluse_lock(&priv->master->bus);
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i3c_bus_for_each_i3cdev(&priv->master->bus, desc)
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{
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manufid = I3C_PID_MANUF_ID(desc->info.pid);
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partid = I3C_PID_PART_ID(desc->info.pid);
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if (manufid == transfer->manufid && partid == transfer->partid)
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{
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obtain = true;
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break;
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}
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}
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i3c_bus_normaluse_unlock(&priv->master->bus);
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if (!obtain)
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{
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nxmutex_unlock(&priv->lock);
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return -ENXIO;
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}
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/* Process the IOCTL command */
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switch (cmd)
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{
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case I3CIOC_PRIV_XFERS:
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DEBUGASSERT(transfer->xfers != NULL);
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/* Perform the transfer */
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ret = i3c_device_do_priv_xfers(desc->dev, transfer->xfers,
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transfer->nxfers);
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break;
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case I3CIOC_GET_DEVINFO:
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DEBUGASSERT(transfer->info != NULL);
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/* Perform the get specified i3c device operating */
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i3c_device_get_info(desc->dev, transfer->info);
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break;
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default:
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ret = -ENOTTY;
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break;
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}
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nxmutex_unlock(&priv->lock);
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return ret;
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}
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/****************************************************************************
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* Name: i3cdrvr_unlink
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****************************************************************************/
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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static int i3cdrvr_unlink(FAR struct inode *inode)
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{
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FAR struct i3c_driver_s *priv;
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int ret;
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/* Get our private data structure */
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DEBUGASSERT(inode != NULL && inode->i_private != NULL);
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priv = (FAR struct i3c_driver_s *)inode->i_private;
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/* Get exclusive access to the I3C driver state structure */
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ret = nxmutex_lock(&priv->lock);
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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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/* Are there open references to the driver data structure? */
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if (priv->crefs <= 0)
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{
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nxmutex_destroy(&priv->lock);
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kmm_free(priv);
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return OK;
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}
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/* No... just mark the driver as unlinked and free the resources when the
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* last client closes their reference to the driver.
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*/
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priv->unlinked = true;
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nxmutex_unlock(&priv->lock);
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return ret;
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}
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#endif
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: i3c_register
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*
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* Description:
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* Create and register the I3C character driver.
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*
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* The I3C character driver is a simple character driver that supports I3C
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* transfers. The intent of this driver is to support I3C testing. It is
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* not suitable for use in any real driver application.
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*
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* Input Parameters:
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* master - the lower half of an the controller object about I3C master
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* driver.
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* bus - The I3C bus number. This will be used as the I3C device minor
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* number. The I3C character device will be registered as /dev/i3cN
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* where N is the minor number
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*
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* Returned Value:
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* OK if the driver was successfully register; A negated errno value is
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* returned on any failure.
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*
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****************************************************************************/
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int i3c_register(FAR struct i3c_master_controller *master, int bus)
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{
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FAR struct i3c_driver_s *priv;
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char devname[DEVNAME_FMTLEN];
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int ret;
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/* Sanity check */
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DEBUGASSERT(master != NULL && (unsigned)bus < 1000);
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priv = kmm_zalloc(sizeof(struct i3c_driver_s));
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if (priv == NULL)
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{
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return -ENOMEM;
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}
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priv->master = master;
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nxmutex_init(&priv->lock);
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/* Create the character device name */
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snprintf(devname, sizeof(devname), DEVNAME_FMT, bus);
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ret = register_driver(devname, &g_i3cdrvr_fops, 0666, priv);
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if (ret < 0)
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{
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/* Free the device structure if we failed to create the character
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* device.
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*/
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nxmutex_destroy(&priv->lock);
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kmm_free(priv);
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}
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/* Return the result of the registration */
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return ret;
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}
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