936df1bcb5
Squashed commit of the following:
Change all calls to usleep() in the OS proper to calls to nxsig_usleep()
sched/signal: Add a new OS internal function nxsig_usleep() that is functionally equivalent to usleep() but does not cause a cancellaption point and does not modify the errno variable.
sched/signal: Add a new OS internal function nxsig_sleep() that is functionally equivalent to sleep() but does not cause a cancellaption point.
1586 lines
44 KiB
C
1586 lines
44 KiB
C
/****************************************************************************
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* drivers/can/can.c
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*
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* Copyright (C) 2008-2009, 2011-2012, 2014-2015, 2017 Gregory Nutt. All
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* rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Copyright (C) 2016 Omni Hoverboards Inc. All rights reserved.
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* Author: Paul Alexander Patience <paul-a.patience@polymtl.ca>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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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 <unistd.h>
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#include <string.h>
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#include <semaphore.h>
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#include <fcntl.h>
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#include <assert.h>
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#include <poll.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/arch.h>
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#include <nuttx/signal.h>
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#include <nuttx/semaphore.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/can/can.h>
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#ifdef CONFIG_CAN_TXREADY
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# include <nuttx/wqueue.h>
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#endif
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#include <nuttx/irq.h>
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#ifdef CONFIG_CAN
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Configuration ************************************************************/
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#ifdef CONFIG_CAN_TXREADY
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# if !defined(CONFIG_SCHED_WORKQUEUE)
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# error Work queue support required in this configuration
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# undef CONFIG_CAN_TXREADY
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# undef CONFIG_CAN_TXREADY_LOPRI
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# undef CONFIG_CAN_TXREADY_HIPRI
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# elif defined(CONFIG_CAN_TXREADY_LOPRI)
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# undef CONFIG_CAN_TXREADY_HIPRI
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# ifdef CONFIG_SCHED_LPWORK
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# define CANWORK LPWORK
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# else
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# error Low priority work queue support required in this configuration
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# undef CONFIG_CAN_TXREADY
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# undef CONFIG_CAN_TXREADY_LOPRI
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# endif
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# elif defined(CONFIG_CAN_TXREADY_HIPRI)
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# ifdef CONFIG_SCHED_HPWORK
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# define CANWORK HPWORK
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# else
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# error High priority work queue support required in this configuration
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# undef CONFIG_CAN_TXREADY
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# undef CONFIG_CAN_TXREADY_HIPRI
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# endif
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# else
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# error No work queue selection
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# undef CONFIG_CAN_TXREADY
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# endif
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#endif
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/* Timing Definitions *******************************************************/
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#define HALF_SECOND_MSEC 500
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#define HALF_SECOND_USEC 500000L
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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/* Semaphore helpers */
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static int can_takesem(FAR sem_t *sem);
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/* Poll helpers */
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#ifndef CONFIG_DISABLE_POLL
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static void can_pollnotify(FAR struct can_dev_s *dev,
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pollevent_t eventset);
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#endif
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/* CAN helpers */
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static uint8_t can_dlc2bytes(uint8_t dlc);
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#if 0 /* Not used */
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static uint8_t can_bytes2dlc(uint8_t nbytes);
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#endif
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#ifdef CONFIG_CAN_TXREADY
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static void can_txready_work(FAR void *arg);
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#endif
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/* Character driver methods */
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static int can_open(FAR struct file *filep);
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static int can_close(FAR struct file *filep);
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static ssize_t can_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen);
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static int can_xmit(FAR struct can_dev_s *dev);
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static ssize_t can_write(FAR struct file *filep,
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FAR const char *buffer, size_t buflen);
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static inline ssize_t can_rtrread(FAR struct can_dev_s *dev,
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FAR struct canioc_rtr_s *rtr);
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static int can_ioctl(FAR struct file *filep, int cmd,
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unsigned long arg);
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#ifndef CONFIG_DISABLE_POLL
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static int can_poll(FAR struct file *filep, FAR struct pollfd *fds,
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bool setup);
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#endif
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static const struct file_operations g_canops =
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{
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can_open, /* open */
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can_close, /* close */
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can_read, /* read */
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can_write, /* write */
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NULL, /* seek */
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can_ioctl /* ioctl */
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#ifndef CONFIG_DISABLE_POLL
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, can_poll /* poll */
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#endif
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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, NULL /* 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: can_takesem
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****************************************************************************/
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static int can_takesem(FAR sem_t *sem)
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{
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int ret;
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/* Take a count from the semaphore, possibly waiting */
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ret = nxsem_wait(sem);
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/* The only case that an error should occur here is if the wait
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* was awakened by a signal
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*/
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DEBUGASSERT(ret == OK || ret == -EINTR);
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return ret;
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}
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/****************************************************************************
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* Name: can_givesem
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****************************************************************************/
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#define can_givesem(sem) nxsem_post(sem)
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/****************************************************************************
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* Name: can_pollnotify
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****************************************************************************/
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#ifndef CONFIG_DISABLE_POLL
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static void can_pollnotify(FAR struct can_dev_s *dev, pollevent_t eventset)
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{
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FAR struct pollfd *fds;
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int i;
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for (i = 0; i < CONFIG_CAN_NPOLLWAITERS; i++)
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{
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fds = dev->cd_fds[i];
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if (fds != NULL)
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{
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fds->revents |= fds->events & eventset;
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if (fds->revents != 0)
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{
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caninfo("Report events: %02x\n", fds->revents);
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nxsem_post(fds->sem);
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}
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}
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}
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}
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#else
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# define can_pollnotify(dev, eventset)
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#endif
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/****************************************************************************
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* Name: can_dlc2bytes
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*
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* Description:
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* In the CAN FD format, the coding of the DLC differs from the standard
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* CAN format. The DLC codes 0 to 8 have the same coding as in standard
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* CAN. But the codes 9 to 15 all imply a data field of 8 bytes with
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* standard CAN. In CAN FD mode, the values 9 to 15 are encoded to values
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* in the range 12 to 64.
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*
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* Input Parameter:
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* dlc - the DLC value to convert to a byte count
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*
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* Returned Value:
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* The number of bytes corresponding to the DLC value.
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*
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****************************************************************************/
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static uint8_t can_dlc2bytes(uint8_t dlc)
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{
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if (dlc > 8)
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{
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#ifdef CONFIG_CAN_FD
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switch (dlc)
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{
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case 9:
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return 12;
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case 10:
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return 16;
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case 11:
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return 20;
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case 12:
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return 24;
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case 13:
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return 32;
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case 14:
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return 48;
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default:
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case 15:
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return 64;
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}
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#else
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return 8;
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#endif
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}
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return dlc;
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}
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/****************************************************************************
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* Name: can_bytes2dlc
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*
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* Description:
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* In the CAN FD format, the coding of the DLC differs from the standard
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* CAN format. The DLC codes 0 to 8 have the same coding as in standard
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* CAN. But the codes 9 to 15 all imply a data field of 8 bytes with
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* standard CAN. In CAN FD mode, the values 9 to 15 are encoded to values
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* in the range 12 to 64.
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*
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* Input Parameter:
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* nbytes - the byte count to convert to a DLC value
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*
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* Returned Value:
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* The encoded DLC value corresponding to at least that number of bytes.
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*
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****************************************************************************/
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#if 0 /* Not used */
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static uint8_t can_bytes2dlc(FAR struct sam_can_s *priv, uint8_t nbytes)
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{
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if (nbytes <= 8)
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{
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return nbytes;
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}
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#ifdef CONFIG_CAN_FD
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else if (nbytes <= 12)
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{
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return 9;
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}
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else if (nbytes <= 16)
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{
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return 10;
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}
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else if (nbytes <= 20)
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{
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return 11;
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}
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else if (nbytes <= 24)
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{
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return 12;
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}
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else if (nbytes <= 32)
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{
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return 13;
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}
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else if (nbytes <= 48)
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{
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return 14;
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}
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else /* if (nbytes <= 64) */
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{
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return 15;
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}
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#else
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else
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{
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return 8;
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}
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#endif
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}
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#endif
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/****************************************************************************
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* Name: can_txready_work
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*
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* Description:
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* This function performs deferred processing from can_txready. See the
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* discription of can_txready below for additionla information.
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*
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****************************************************************************/
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#ifdef CONFIG_CAN_TXREADY
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static void can_txready_work(FAR void *arg)
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{
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FAR struct can_dev_s *dev = (FAR struct can_dev_s *)arg;
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irqstate_t flags;
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int ret;
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caninfo("xmit head: %d queue: %d tail: %d\n",
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dev->cd_xmit.tx_head, dev->cd_xmit.tx_queue,
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dev->cd_xmit.tx_tail);
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/* Verify that the xmit FIFO is not empty. The following operations must
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* be performed with interrupt disabled.
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*/
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flags = enter_critical_section();
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if (dev->cd_xmit.tx_head != dev->cd_xmit.tx_tail)
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{
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/* Send the next message in the FIFO. */
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ret = can_xmit(dev);
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/* If the message was successfully queued in the H/W FIFO, then
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* can_txdone() should have been called. If the S/W FIFO were
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* full before then there should now be free space in the S/W FIFO.
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*/
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if (ret >= 0)
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{
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/* Are there any threads waiting for space in the TX FIFO? */
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if (dev->cd_ntxwaiters > 0)
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{
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/* Yes.. Inform them that new xmit space is available */
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can_givesem(&dev->cd_xmit.tx_sem);
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}
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}
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}
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leave_critical_section(flags);
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}
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#endif
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/****************************************************************************
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* Name: can_open
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*
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* Description:
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* This function is called whenever the CAN device is opened.
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*
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****************************************************************************/
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static int can_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 can_dev_s *dev = inode->i_private;
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uint8_t tmp;
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int ret;
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caninfo("ocount: %d\n", dev->cd_ocount);
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/* If the port is the middle of closing, wait until the close is finished */
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ret = can_takesem(&dev->cd_closesem);
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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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|
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/* Increment the count of references to the device. If this is the first
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* time that the driver has been opened for this device, then initialize
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* the device.
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*/
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tmp = dev->cd_ocount + 1;
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if (tmp == 0)
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{
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/* More than 255 opens; uint8_t overflows to zero */
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ret = -EMFILE;
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}
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else
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{
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/* Check if this is the first time that the driver has been opened. */
|
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|
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if (tmp == 1)
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{
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/* Yes.. perform one time hardware initialization. */
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|
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irqstate_t flags = enter_critical_section();
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ret = dev_setup(dev);
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if (ret >= 0)
|
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{
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/* Mark the FIFOs empty */
|
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|
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dev->cd_xmit.tx_head = 0;
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dev->cd_xmit.tx_queue = 0;
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dev->cd_xmit.tx_tail = 0;
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dev->cd_recv.rx_head = 0;
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dev->cd_recv.rx_tail = 0;
|
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|
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/* Finally, Enable the CAN RX interrupt */
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|
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dev_rxint(dev, true);
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|
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/* Save the new open count only on success */
|
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|
|
dev->cd_ocount = 1;
|
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}
|
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|
|
leave_critical_section(flags);
|
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}
|
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else
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{
|
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/* Save the incremented open count */
|
|
|
|
dev->cd_ocount = tmp;
|
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}
|
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}
|
|
|
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can_givesem(&dev->cd_closesem);
|
|
return ret;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: can_close
|
|
*
|
|
* Description:
|
|
* This routine is called when the CAN device is closed.
|
|
* It waits for the last remaining data to be sent.
|
|
*
|
|
****************************************************************************/
|
|
|
|
static int can_close(FAR struct file *filep)
|
|
{
|
|
FAR struct inode *inode = filep->f_inode;
|
|
FAR struct can_dev_s *dev = inode->i_private;
|
|
irqstate_t flags;
|
|
int ret;
|
|
|
|
caninfo("ocount: %d\n", dev->cd_ocount);
|
|
|
|
ret = can_takesem(&dev->cd_closesem);
|
|
if (ret < 0)
|
|
{
|
|
return ret;
|
|
}
|
|
|
|
/* Decrement the references to the driver. If the reference count will
|
|
* decrement to 0, then uninitialize the driver.
|
|
*/
|
|
|
|
if (dev->cd_ocount > 1)
|
|
{
|
|
dev->cd_ocount--;
|
|
goto errout;
|
|
}
|
|
|
|
/* There are no more references to the port */
|
|
|
|
dev->cd_ocount = 0;
|
|
|
|
/* Stop accepting input */
|
|
|
|
dev_rxint(dev, false);
|
|
|
|
/* Now we wait for the transmit FIFO to clear */
|
|
|
|
while (dev->cd_xmit.tx_head != dev->cd_xmit.tx_tail)
|
|
{
|
|
#ifndef CONFIG_DISABLE_SIGNALS
|
|
nxsig_usleep(HALF_SECOND_USEC);
|
|
#else
|
|
up_mdelay(HALF_SECOND_MSEC);
|
|
#endif
|
|
}
|
|
|
|
/* And wait for the TX hardware FIFO to drain */
|
|
|
|
while (!dev_txempty(dev))
|
|
{
|
|
#ifndef CONFIG_DISABLE_SIGNALS
|
|
nxsig_usleep(HALF_SECOND_USEC);
|
|
#else
|
|
up_mdelay(HALF_SECOND_MSEC);
|
|
#endif
|
|
}
|
|
|
|
/* Free the IRQ and disable the CAN device */
|
|
|
|
flags = enter_critical_section(); /* Disable interrupts */
|
|
dev_shutdown(dev); /* Disable the CAN */
|
|
leave_critical_section(flags);
|
|
|
|
errout:
|
|
can_givesem(&dev->cd_closesem);
|
|
return ret;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: can_read
|
|
*
|
|
* Description:
|
|
* Read standard CAN messages
|
|
*
|
|
****************************************************************************/
|
|
|
|
static ssize_t can_read(FAR struct file *filep, FAR char *buffer,
|
|
size_t buflen)
|
|
{
|
|
FAR struct inode *inode = filep->f_inode;
|
|
FAR struct can_dev_s *dev = inode->i_private;
|
|
size_t nread;
|
|
irqstate_t flags;
|
|
int ret = 0;
|
|
|
|
caninfo("buflen: %d\n", buflen);
|
|
|
|
/* The caller must provide enough memory to catch the smallest possible
|
|
* message. This is not a system error condition, but we won't permit
|
|
* it, Hence we return 0.
|
|
*/
|
|
|
|
if (buflen >= CAN_MSGLEN(0))
|
|
{
|
|
/* Interrupts must be disabled while accessing the cd_recv FIFO */
|
|
|
|
flags = enter_critical_section();
|
|
|
|
#ifdef CONFIG_CAN_ERRORS
|
|
/* Check for internal errors */
|
|
|
|
if (dev->cd_error != 0)
|
|
{
|
|
FAR struct can_msg_s *msg;
|
|
|
|
/* Detected an internal driver error. Generate a
|
|
* CAN_ERROR_MESSAGE
|
|
*/
|
|
|
|
if (buflen < CAN_MSGLEN(CAN_ERROR_DLC))
|
|
{
|
|
goto return_with_irqdisabled;
|
|
}
|
|
|
|
msg = (FAR struct can_msg_s *)buffer;
|
|
msg->cm_hdr.ch_id = CAN_ERROR_INTERNAL;
|
|
msg->cm_hdr.ch_dlc = CAN_ERROR_DLC;
|
|
msg->cm_hdr.ch_rtr = 0;
|
|
msg->cm_hdr.ch_error = 1;
|
|
#ifdef CONFIG_CAN_EXTID
|
|
msg->cm_hdr.ch_extid = 0;
|
|
#endif
|
|
msg->cm_hdr.ch_unused = 0;
|
|
memset(&(msg->cm_data), 0, CAN_ERROR_DLC);
|
|
msg->cm_data[5] = dev->cd_error;
|
|
|
|
/* Reset the error flag */
|
|
|
|
dev->cd_error = 0;
|
|
|
|
ret = CAN_MSGLEN(CAN_ERROR_DLC);
|
|
goto return_with_irqdisabled;
|
|
}
|
|
#endif /* CONFIG_CAN_ERRORS */
|
|
|
|
while (dev->cd_recv.rx_head == dev->cd_recv.rx_tail)
|
|
{
|
|
/* The receive FIFO is empty -- was non-blocking mode selected? */
|
|
|
|
if (filep->f_oflags & O_NONBLOCK)
|
|
{
|
|
ret = -EAGAIN;
|
|
goto return_with_irqdisabled;
|
|
}
|
|
|
|
/* Wait for a message to be received */
|
|
|
|
DEBUGASSERT(dev->cd_nrxwaiters < 255);
|
|
dev->cd_nrxwaiters++;
|
|
ret = can_takesem(&dev->cd_recv.rx_sem);
|
|
dev->cd_nrxwaiters--;
|
|
if (ret < 0)
|
|
{
|
|
goto return_with_irqdisabled;
|
|
}
|
|
}
|
|
|
|
/* The cd_recv FIFO is not empty. Copy all buffered data that will fit
|
|
* in the user buffer.
|
|
*/
|
|
|
|
nread = 0;
|
|
do
|
|
{
|
|
/* Will the next message in the FIFO fit into the user buffer? */
|
|
|
|
FAR struct can_msg_s *msg = &dev->cd_recv.rx_buffer[dev->cd_recv.rx_head];
|
|
int nbytes = can_dlc2bytes(msg->cm_hdr.ch_dlc);
|
|
int msglen = CAN_MSGLEN(nbytes);
|
|
|
|
if (nread + msglen > buflen)
|
|
{
|
|
break;
|
|
}
|
|
|
|
/* Copy the message to the user buffer */
|
|
|
|
memcpy(&buffer[nread], msg, msglen);
|
|
nread += msglen;
|
|
|
|
/* Increment the head of the circular message buffer */
|
|
|
|
if (++dev->cd_recv.rx_head >= CONFIG_CAN_FIFOSIZE)
|
|
{
|
|
dev->cd_recv.rx_head = 0;
|
|
}
|
|
}
|
|
while (dev->cd_recv.rx_head != dev->cd_recv.rx_tail);
|
|
|
|
/* All on the messages have bee transferred. Return the number of bytes
|
|
* that were read.
|
|
*/
|
|
|
|
ret = nread;
|
|
|
|
return_with_irqdisabled:
|
|
leave_critical_section(flags);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: can_xmit
|
|
*
|
|
* Description:
|
|
* Send the message at the head of the cd_xmit FIFO
|
|
*
|
|
* Assumptions:
|
|
* Called with interrupts disabled
|
|
*
|
|
****************************************************************************/
|
|
|
|
static int can_xmit(FAR struct can_dev_s *dev)
|
|
{
|
|
int tmpndx;
|
|
int ret = -EBUSY;
|
|
|
|
caninfo("xmit head: %d queue: %d tail: %d\n",
|
|
dev->cd_xmit.tx_head, dev->cd_xmit.tx_queue, dev->cd_xmit.tx_tail);
|
|
|
|
/* If there is nothing to send, then just disable interrupts and return */
|
|
|
|
if (dev->cd_xmit.tx_head == dev->cd_xmit.tx_tail)
|
|
{
|
|
DEBUGASSERT(dev->cd_xmit.tx_queue == dev->cd_xmit.tx_head);
|
|
|
|
#ifndef CONFIG_CAN_TXREADY
|
|
/* We can disable CAN TX interrupts -- unless there is a H/W FIFO. In
|
|
* that case, TX interrupts must stay enabled until the H/W FIFO is
|
|
* fully emptied.
|
|
*/
|
|
|
|
dev_txint(dev, false);
|
|
#endif
|
|
return -EIO;
|
|
}
|
|
|
|
/* Check if we have already queued all of the data in the TX fifo.
|
|
*
|
|
* tx_tail: Incremented in can_write each time a message is queued in the FIFO
|
|
* tx_head: Incremented in can_txdone each time a message completes
|
|
* tx_queue: Incremented each time that a message is sent to the hardware.
|
|
*
|
|
* Logically (ignoring buffer wrap-around): tx_head <= tx_queue <= tx_tail
|
|
* tx_head == tx_queue == tx_tail means that the FIFO is empty
|
|
* tx_head < tx_queue == tx_tail means that all data has been queued, but
|
|
* we are still waiting for transmissions to complete.
|
|
*/
|
|
|
|
while (dev->cd_xmit.tx_queue != dev->cd_xmit.tx_tail && dev_txready(dev))
|
|
{
|
|
/* No.. The FIFO should not be empty in this case */
|
|
|
|
DEBUGASSERT(dev->cd_xmit.tx_head != dev->cd_xmit.tx_tail);
|
|
|
|
/* Increment the FIFO queue index before sending (because dev_send()
|
|
* might call can_txdone()).
|
|
*/
|
|
|
|
tmpndx = dev->cd_xmit.tx_queue;
|
|
if (++dev->cd_xmit.tx_queue >= CONFIG_CAN_FIFOSIZE)
|
|
{
|
|
dev->cd_xmit.tx_queue = 0;
|
|
}
|
|
|
|
/* Send the next message at the FIFO queue index */
|
|
|
|
ret = dev_send(dev, &dev->cd_xmit.tx_buffer[tmpndx]);
|
|
if (ret < 0)
|
|
{
|
|
canerr("dev_send failed: %d\n", ret);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Make sure that TX interrupts are enabled */
|
|
|
|
dev_txint(dev, true);
|
|
return ret;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: can_write
|
|
****************************************************************************/
|
|
|
|
static ssize_t can_write(FAR struct file *filep, FAR const char *buffer,
|
|
size_t buflen)
|
|
{
|
|
FAR struct inode *inode = filep->f_inode;
|
|
FAR struct can_dev_s *dev = inode->i_private;
|
|
FAR struct can_txfifo_s *fifo = &dev->cd_xmit;
|
|
FAR struct can_msg_s *msg;
|
|
bool inactive;
|
|
ssize_t nsent = 0;
|
|
irqstate_t flags;
|
|
int nexttail;
|
|
int nbytes;
|
|
int msglen;
|
|
int ret = 0;
|
|
|
|
caninfo("buflen: %d\n", buflen);
|
|
|
|
/* Interrupts must disabled throughout the following */
|
|
|
|
flags = enter_critical_section();
|
|
|
|
/* Check if the TX is inactive when we started. In certain race conditions,
|
|
* there may be a pending interrupt to kick things back off, but we will
|
|
* be sure here that there is not. That the hardware is IDLE and will
|
|
* need to be kick-started.
|
|
*/
|
|
|
|
inactive = dev_txempty(dev);
|
|
|
|
/* Add the messages to the FIFO. Ignore any trailing messages that are
|
|
* shorter than the minimum.
|
|
*/
|
|
|
|
while ((buflen - nsent) >= CAN_MSGLEN(0))
|
|
{
|
|
/* Check if adding this new message would over-run the drivers ability
|
|
* to enqueue xmit data.
|
|
*/
|
|
|
|
nexttail = fifo->tx_tail + 1;
|
|
if (nexttail >= CONFIG_CAN_FIFOSIZE)
|
|
{
|
|
nexttail = 0;
|
|
}
|
|
|
|
/* If the XMIT FIFO becomes full, then wait for space to become available */
|
|
|
|
while (nexttail == fifo->tx_head)
|
|
{
|
|
/* The transmit FIFO is full -- was non-blocking mode selected? */
|
|
|
|
if ((filep->f_oflags & O_NONBLOCK) != 0)
|
|
{
|
|
if (nsent == 0)
|
|
{
|
|
ret = -EAGAIN;
|
|
}
|
|
else
|
|
{
|
|
ret = nsent;
|
|
}
|
|
|
|
goto return_with_irqdisabled;
|
|
}
|
|
|
|
/* If the TX hardware was inactive when we started, then we will have
|
|
* start the XMIT sequence generate the TX done interrupts needed
|
|
* to clear the FIFO.
|
|
*/
|
|
|
|
if (inactive)
|
|
{
|
|
(void)can_xmit(dev);
|
|
}
|
|
|
|
/* Wait for a message to be sent */
|
|
|
|
DEBUGASSERT(dev->cd_ntxwaiters < 255);
|
|
dev->cd_ntxwaiters++;
|
|
ret = can_takesem(&fifo->tx_sem);
|
|
dev->cd_ntxwaiters--;
|
|
if (ret < 0)
|
|
{
|
|
goto return_with_irqdisabled;
|
|
}
|
|
|
|
/* Re-check the FIFO state */
|
|
|
|
inactive = dev_txempty(dev);
|
|
}
|
|
|
|
/* We get here if there is space at the end of the FIFO. Add the new
|
|
* CAN message at the tail of the FIFO.
|
|
*/
|
|
|
|
msg = (FAR struct can_msg_s *)&buffer[nsent];
|
|
nbytes = can_dlc2bytes(msg->cm_hdr.ch_dlc);
|
|
msglen = CAN_MSGLEN(nbytes);
|
|
memcpy(&fifo->tx_buffer[fifo->tx_tail], msg, msglen);
|
|
|
|
/* Increment the tail of the circular buffer */
|
|
|
|
fifo->tx_tail = nexttail;
|
|
|
|
/* Increment the number of bytes that were sent */
|
|
|
|
nsent += msglen;
|
|
}
|
|
|
|
/* We get here after all messages have been added to the FIFO. Check if
|
|
* we need to kick off the XMIT sequence.
|
|
*/
|
|
|
|
if (inactive)
|
|
{
|
|
(void)can_xmit(dev);
|
|
}
|
|
|
|
/* Return the number of bytes that were sent */
|
|
|
|
ret = nsent;
|
|
|
|
return_with_irqdisabled:
|
|
leave_critical_section(flags);
|
|
return ret;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: can_rtrread
|
|
*
|
|
* Description:
|
|
* Read RTR messages. The RTR message is a special message -- it is an
|
|
* outgoing message that says "Please re-transmit the message with the
|
|
* same identifier as this message. So the RTR read is really a
|
|
* send-wait-receive operation.
|
|
*
|
|
****************************************************************************/
|
|
|
|
static inline ssize_t can_rtrread(FAR struct can_dev_s *dev,
|
|
FAR struct canioc_rtr_s *rtr)
|
|
{
|
|
FAR struct can_rtrwait_s *wait = NULL;
|
|
irqstate_t flags;
|
|
int i;
|
|
int ret = -ENOMEM;
|
|
|
|
/* Disable interrupts through this operation */
|
|
|
|
flags = enter_critical_section();
|
|
|
|
/* Find an available slot in the pending RTR list */
|
|
|
|
for (i = 0; i < CONFIG_CAN_NPENDINGRTR; i++)
|
|
{
|
|
FAR struct can_rtrwait_s *tmp = &dev->cd_rtr[i];
|
|
if (!rtr->ci_msg)
|
|
{
|
|
tmp->cr_id = rtr->ci_id;
|
|
tmp->cr_msg = rtr->ci_msg;
|
|
dev->cd_npendrtr++;
|
|
wait = tmp;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (wait)
|
|
{
|
|
/* Send the remote transmission request */
|
|
|
|
ret = dev_remoterequest(dev, wait->cr_id);
|
|
if (ret >= 0)
|
|
{
|
|
/* Then wait for the response */
|
|
|
|
ret = can_takesem(&wait->cr_sem);
|
|
}
|
|
}
|
|
|
|
leave_critical_section(flags);
|
|
return ret;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: can_ioctl
|
|
****************************************************************************/
|
|
|
|
static int can_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
|
|
{
|
|
FAR struct inode *inode = filep->f_inode;
|
|
FAR struct can_dev_s *dev = inode->i_private;
|
|
int ret = OK;
|
|
|
|
caninfo("cmd: %d arg: %ld\n", cmd, arg);
|
|
|
|
/* Handle built-in ioctl commands */
|
|
|
|
switch (cmd)
|
|
{
|
|
/* CANIOC_RTR: Send the remote transmission request and wait for the
|
|
* response. Argument is a reference to struct canioc_rtr_s
|
|
* (casting to uintptr_t first eliminates complaints on some
|
|
* architectures where the sizeof long is different from the size of
|
|
* a pointer).
|
|
*/
|
|
|
|
case CANIOC_RTR:
|
|
ret = can_rtrread(dev, (FAR struct canioc_rtr_s *)((uintptr_t)arg));
|
|
break;
|
|
|
|
/* Not a "built-in" ioctl command.. perhaps it is unique to this
|
|
* lower-half, device driver.
|
|
*/
|
|
|
|
default:
|
|
ret = dev_ioctl(dev, cmd, arg);
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: can_poll
|
|
****************************************************************************/
|
|
|
|
#ifndef CONFIG_DISABLE_POLL
|
|
static int can_poll(FAR struct file *filep, FAR struct pollfd *fds,
|
|
bool setup)
|
|
{
|
|
FAR struct inode *inode = (FAR struct inode *)filep->f_inode;
|
|
FAR struct can_dev_s *dev = (FAR struct can_dev_s *)inode->i_private;
|
|
pollevent_t eventset;
|
|
int ndx;
|
|
int ret;
|
|
int i;
|
|
|
|
/* Some sanity checking */
|
|
|
|
#ifdef CONFIG_DEBUG_FEATURES
|
|
if (dev == NULL || fds == NULL)
|
|
{
|
|
return -ENODEV;
|
|
}
|
|
#endif
|
|
|
|
/* Get exclusive access to the poll structures */
|
|
|
|
ret = can_takesem(&dev->cd_pollsem);
|
|
if (ret < 0)
|
|
{
|
|
/* A signal received while waiting for access to the poll data
|
|
* will abort the operation
|
|
*/
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* Are we setting up the poll? Or tearing it down? */
|
|
|
|
if (setup)
|
|
{
|
|
/* This is a request to set up the poll. Find an available
|
|
* slot for the poll structure reference.
|
|
*/
|
|
|
|
for (i = 0; i < CONFIG_CAN_NPOLLWAITERS; i++)
|
|
{
|
|
/* Find an available slot */
|
|
|
|
if (dev->cd_fds[i] == NULL)
|
|
{
|
|
/* Bind the poll structure and this slot */
|
|
|
|
dev->cd_fds[i] = fds;
|
|
fds->priv = &dev->cd_fds[i];
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (i >= CONFIG_CAN_NPOLLWAITERS)
|
|
{
|
|
fds->priv = NULL;
|
|
ret = -EBUSY;
|
|
goto errout;
|
|
}
|
|
|
|
/* Should we immediately notify on any of the requested events?
|
|
* First, check if the xmit buffer is full.
|
|
*
|
|
* Get exclusive access to the cd_xmit buffer indices. NOTE: that
|
|
* we do not let this wait be interrupted by a signal (we probably
|
|
* should, but that would be a little awkward).
|
|
*/
|
|
|
|
eventset = 0;
|
|
|
|
DEBUGASSERT(dev->cd_ntxwaiters < 255);
|
|
dev->cd_ntxwaiters++;
|
|
do
|
|
{
|
|
ret = can_takesem(&dev->cd_xmit.tx_sem);
|
|
}
|
|
while (ret < 0);
|
|
dev->cd_ntxwaiters--;
|
|
|
|
ndx = dev->cd_xmit.tx_head + 1;
|
|
if (ndx >= CONFIG_CAN_FIFOSIZE)
|
|
{
|
|
ndx = 0;
|
|
}
|
|
|
|
if (ndx != dev->cd_xmit.tx_tail)
|
|
{
|
|
eventset |= fds->events & POLLOUT;
|
|
}
|
|
|
|
can_givesem(&dev->cd_xmit.tx_sem);
|
|
|
|
/* Check if the receive buffer is empty.
|
|
*
|
|
* Get exclusive access to the cd_recv buffer indices. NOTE: that
|
|
* we do not let this wait be interrupted by a signal (we probably
|
|
* should, but that would be a little awkward).
|
|
*/
|
|
|
|
DEBUGASSERT(dev->cd_nrxwaiters < 255);
|
|
dev->cd_nrxwaiters++;
|
|
do
|
|
{
|
|
ret = can_takesem(&dev->cd_recv.rx_sem);
|
|
}
|
|
while (ret < 0);
|
|
dev->cd_nrxwaiters--;
|
|
|
|
if (dev->cd_recv.rx_head != dev->cd_recv.rx_tail)
|
|
{
|
|
eventset |= fds->events & POLLIN;
|
|
}
|
|
|
|
can_givesem(&dev->cd_recv.rx_sem);
|
|
|
|
if (eventset != 0)
|
|
{
|
|
can_pollnotify(dev, eventset);
|
|
}
|
|
}
|
|
else if (fds->priv != NULL)
|
|
{
|
|
/* This is a request to tear down the poll */
|
|
|
|
struct pollfd **slot = (struct pollfd **)fds->priv;
|
|
|
|
#ifdef CONFIG_DEBUG_FEATURES
|
|
if (slot == NULL)
|
|
{
|
|
ret = -EIO;
|
|
goto errout;
|
|
}
|
|
#endif
|
|
|
|
/* Remove all memory of the poll setup */
|
|
|
|
*slot = NULL;
|
|
fds->priv = NULL;
|
|
}
|
|
|
|
errout:
|
|
can_givesem(&dev->cd_pollsem);
|
|
return ret;
|
|
}
|
|
#endif
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: can_register
|
|
*
|
|
* Description:
|
|
* Register serial console and serial ports.
|
|
*
|
|
****************************************************************************/
|
|
|
|
int can_register(FAR const char *path, FAR struct can_dev_s *dev)
|
|
{
|
|
int i;
|
|
|
|
/* Initialize the CAN device structure */
|
|
|
|
dev->cd_ocount = 0;
|
|
dev->cd_ntxwaiters = 0;
|
|
dev->cd_nrxwaiters = 0;
|
|
dev->cd_npendrtr = 0;
|
|
#ifdef CONFIG_CAN_ERRORS
|
|
dev->cd_error = 0;
|
|
#endif
|
|
|
|
/* Initialize semaphores */
|
|
|
|
nxsem_init(&dev->cd_xmit.tx_sem, 0, 1);
|
|
nxsem_init(&dev->cd_recv.rx_sem, 0, 1);
|
|
nxsem_init(&dev->cd_closesem, 0, 1);
|
|
#ifndef CONFIG_DISABLE_POLL
|
|
nxsem_init(&dev->cd_pollsem, 0, 1);
|
|
#endif
|
|
|
|
for (i = 0; i < CONFIG_CAN_NPENDINGRTR; i++)
|
|
{
|
|
/* Initialize wait semaphores. These semaphores are used for signaling
|
|
* and should not have priority inheritance enabled.
|
|
*/
|
|
|
|
nxsem_init(&dev->cd_rtr[i].cr_sem, 0, 0);
|
|
nxsem_setprotocol(&dev->cd_rtr[i].cr_sem, SEM_PRIO_NONE);
|
|
dev->cd_rtr[i].cr_msg = NULL;
|
|
}
|
|
|
|
/* Initialize/reset the CAN hardware */
|
|
|
|
dev_reset(dev);
|
|
|
|
/* Register the CAN device */
|
|
|
|
caninfo("Registering %s\n", path);
|
|
return register_driver(path, &g_canops, 0666, dev);
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: can_receive
|
|
*
|
|
* Description:
|
|
* Called from the CAN interrupt handler when new read data is available
|
|
*
|
|
* Input Parameters:
|
|
* dev - CAN driver state structure
|
|
* hdr - CAN message header
|
|
* data - CAN message data (if DLC > 0)
|
|
*
|
|
* Returned Value:
|
|
* OK on success; a negated errno on failure.
|
|
*
|
|
* Assumptions:
|
|
* CAN interrupts are disabled.
|
|
*
|
|
****************************************************************************/
|
|
|
|
int can_receive(FAR struct can_dev_s *dev, FAR struct can_hdr_s *hdr,
|
|
FAR uint8_t *data)
|
|
{
|
|
FAR struct can_rxfifo_s *fifo = &dev->cd_recv;
|
|
FAR uint8_t *dest;
|
|
int nexttail;
|
|
int errcode = -ENOMEM;
|
|
int i;
|
|
|
|
caninfo("ID: %d DLC: %d\n", hdr->ch_id, hdr->ch_dlc);
|
|
|
|
/* Check if adding this new message would over-run the drivers ability to
|
|
* enqueue read data.
|
|
*/
|
|
|
|
nexttail = fifo->rx_tail + 1;
|
|
if (nexttail >= CONFIG_CAN_FIFOSIZE)
|
|
{
|
|
nexttail = 0;
|
|
}
|
|
|
|
/* First, check if this response matches any RTR response that we may be
|
|
* waiting for.
|
|
*/
|
|
|
|
if (dev->cd_npendrtr > 0)
|
|
{
|
|
/* There are pending RTR requests -- search the lists of requests
|
|
* and see any any matches this new message.
|
|
*/
|
|
|
|
for (i = 0; i < CONFIG_CAN_NPENDINGRTR; i++)
|
|
{
|
|
FAR struct can_rtrwait_s *rtr = &dev->cd_rtr[i];
|
|
FAR struct can_msg_s *msg = rtr->cr_msg;
|
|
|
|
/* Check if the entry is valid and if the ID matches. A valid
|
|
* entry has a non-NULL receiving address
|
|
*/
|
|
|
|
if (msg && hdr->ch_id == rtr->cr_id)
|
|
{
|
|
int nbytes;
|
|
|
|
/* We have the response... copy the data to the user's buffer */
|
|
|
|
memcpy(&msg->cm_hdr, hdr, sizeof(struct can_hdr_s));
|
|
|
|
nbytes = can_dlc2bytes(hdr->ch_dlc);
|
|
for (i = 0, dest = msg->cm_data; i < nbytes; i++)
|
|
{
|
|
*dest++ = *data++;
|
|
}
|
|
|
|
/* Mark the entry unused */
|
|
|
|
rtr->cr_msg = NULL;
|
|
dev->cd_npendrtr--;
|
|
|
|
/* And restart the waiting thread */
|
|
|
|
can_givesem(&rtr->cr_sem);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Refuse the new data if the FIFO is full */
|
|
|
|
if (nexttail != fifo->rx_head)
|
|
{
|
|
int nbytes;
|
|
|
|
/* Add the new, decoded CAN message at the tail of the FIFO.
|
|
*
|
|
* REVISIT: In the CAN FD format, the coding of the DLC differs from
|
|
* the standard CAN format. The DLC codes 0 to 8 have the same coding
|
|
* as in standard CAN, the codes 9 to 15, which in standard CAN all
|
|
* code a data field of 8 bytes, are encoded:
|
|
*
|
|
* 9->12, 10->16, 11->20, 12->24, 13->32, 14->48, 15->64
|
|
*/
|
|
|
|
memcpy(&fifo->rx_buffer[fifo->rx_tail].cm_hdr, hdr, sizeof(struct can_hdr_s));
|
|
|
|
nbytes = can_dlc2bytes(hdr->ch_dlc);
|
|
for (i = 0, dest = fifo->rx_buffer[fifo->rx_tail].cm_data; i < nbytes; i++)
|
|
{
|
|
*dest++ = *data++;
|
|
}
|
|
|
|
/* Increment the tail of the circular buffer */
|
|
|
|
fifo->rx_tail = nexttail;
|
|
|
|
/* The increment the counting semaphore. The maximum value should be
|
|
* CONFIG_CAN_FIFOSIZE -- one possible count for each allocated
|
|
* message buffer.
|
|
*/
|
|
|
|
if (dev->cd_nrxwaiters > 0)
|
|
{
|
|
can_givesem(&fifo->rx_sem);
|
|
}
|
|
|
|
errcode = OK;
|
|
|
|
/* Notify all poll/select waiters that they can read from the
|
|
* cd_recv buffer
|
|
*/
|
|
|
|
can_pollnotify(dev, POLLIN);
|
|
}
|
|
#ifdef CONFIG_CAN_ERRORS
|
|
else
|
|
{
|
|
/* Report rx overflow error */
|
|
|
|
dev->cd_error |= CAN_ERROR5_RXOVERFLOW;
|
|
}
|
|
#endif
|
|
|
|
return errcode;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: can_txdone
|
|
*
|
|
* Description:
|
|
* Called when the hardware has processed the outgoing TX message. This
|
|
* normally means that the CAN messages was sent out on the wire. But
|
|
* if the CAN hardware supports a H/W TX FIFO, then this call may mean
|
|
* only that the CAN message has been added to the H/W FIFO. In either
|
|
* case, the upper-half CAN driver can remove the outgoing message from
|
|
* the S/W FIFO and discard it.
|
|
*
|
|
* This function may be called in different contexts, depending upon the
|
|
* nature of the underlying CAN hardware.
|
|
*
|
|
* 1. No H/W TX FIFO (CONFIG_CAN_TXREADY not defined)
|
|
*
|
|
* This function is only called from the CAN interrupt handler at the
|
|
* completion of a send operation.
|
|
*
|
|
* can_write() -> can_xmit() -> dev_send()
|
|
* CAN interrupt -> can_txdone()
|
|
*
|
|
* If the CAN hardware is busy, then the call to dev_send() will
|
|
* fail, the S/W TX FIFO will accumulate outgoing messages, and the
|
|
* thread calling can_write() may eventually block waiting for space in
|
|
* the S/W TX FIFO.
|
|
*
|
|
* When the CAN hardware completes the transfer and processes the
|
|
* CAN interrupt, the call to can_txdone() will make space in the S/W
|
|
* TX FIFO and will awaken the waiting can_write() thread.
|
|
*
|
|
* 2a. H/W TX FIFO (CONFIG_CAN_TXREADY=y) and S/W TX FIFO not full
|
|
*
|
|
* This function will be called back from dev_send() immediately when a
|
|
* new CAN message is added to H/W TX FIFO:
|
|
*
|
|
* can_write() -> can_xmit() -> dev_send() -> can_txdone()
|
|
*
|
|
* When the H/W TX FIFO becomes full, dev_send() will fail and
|
|
* can_txdone() will not be called. In this case the S/W TX FIFO will
|
|
* accumulate outgoing messages, and the thread calling can_write() may
|
|
* eventually block waiting for space in the S/W TX FIFO.
|
|
*
|
|
* 2b. H/W TX FIFO (CONFIG_CAN_TXREADY=y) and S/W TX FIFO full
|
|
*
|
|
* In this case, the thread calling can_write() is blocked waiting for
|
|
* space in the S/W TX FIFO. can_txdone() will be called, indirectly,
|
|
* from can_txready_work() running on the thread of the work queue.
|
|
*
|
|
* CAN interrupt -> can_txready() -> Schedule can_txready_work()
|
|
* can_txready_work() -> can_xmit() -> dev_send() -> can_txdone()
|
|
*
|
|
* The call dev_send() should not fail in this case and the subsequent
|
|
* call to can_txdone() will make space in the S/W TX FIFO and will
|
|
* awaken the waiting thread.
|
|
*
|
|
* Input Parameters:
|
|
* dev - The specific CAN device
|
|
* hdr - The 16-bit CAN header
|
|
* data - An array contain the CAN data.
|
|
*
|
|
* Returned Value:
|
|
* OK on success; a negated errno on failure.
|
|
*
|
|
* Assumptions:
|
|
* Interrupts are disabled. This is required by can_xmit() which is called
|
|
* by this function. Interrupts are explicitly disabled when called
|
|
* through can_write(). Interrupts are expected be disabled when called
|
|
* from the CAN interrupt handler.
|
|
*
|
|
****************************************************************************/
|
|
|
|
int can_txdone(FAR struct can_dev_s *dev)
|
|
{
|
|
int ret = -ENOENT;
|
|
|
|
caninfo("xmit head: %d queue: %d tail: %d\n",
|
|
dev->cd_xmit.tx_head, dev->cd_xmit.tx_queue, dev->cd_xmit.tx_tail);
|
|
|
|
/* Verify that the xmit FIFO is not empty */
|
|
|
|
if (dev->cd_xmit.tx_head != dev->cd_xmit.tx_tail)
|
|
{
|
|
/* The tx_queue index is incremented each time can_xmit() queues
|
|
* the transmission. When can_txdone() is called, the tx_queue
|
|
* index should always have been advanced beyond the current tx_head
|
|
* index.
|
|
*/
|
|
|
|
DEBUGASSERT(dev->cd_xmit.tx_head != dev->cd_xmit.tx_queue);
|
|
|
|
/* Remove the message at the head of the xmit FIFO */
|
|
|
|
if (++dev->cd_xmit.tx_head >= CONFIG_CAN_FIFOSIZE)
|
|
{
|
|
dev->cd_xmit.tx_head = 0;
|
|
}
|
|
|
|
/* Send the next message in the FIFO */
|
|
|
|
(void)can_xmit(dev);
|
|
|
|
/* Are there any threads waiting for space in the TX FIFO? */
|
|
|
|
if (dev->cd_ntxwaiters > 0)
|
|
{
|
|
/* Yes.. Inform them that new xmit space is available */
|
|
|
|
ret = can_givesem(&dev->cd_xmit.tx_sem);
|
|
}
|
|
else
|
|
{
|
|
ret = OK;
|
|
}
|
|
}
|
|
|
|
/* Notify all poll/select waiters that they can write to the cd_xmit
|
|
* buffer
|
|
*/
|
|
|
|
can_pollnotify(dev, POLLOUT);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: can_txready
|
|
*
|
|
* Description:
|
|
* Called from the CAN interrupt handler at the completion of a send
|
|
* operation. This interface is needed only for CAN hardware that
|
|
* supports queing of outgoing messages in a H/W FIFO.
|
|
*
|
|
* The CAN upper half driver also supports a queue of output messages in a
|
|
* S/W FIFO. Messages are added to that queue when when can_write() is
|
|
* called and removed from the queue in can_txdone() when each TX message
|
|
* is complete.
|
|
*
|
|
* After each message is added to the S/W FIFO, the CAN upper half driver
|
|
* will attempt to send the message by calling into the lower half driver.
|
|
* That send will not be performed if the lower half driver is busy, i.e.,
|
|
* if dev_txready() returns false. In that case, the number of messages in
|
|
* the S/W FIFO can grow. If the S/W FIFO becomes full, then can_write()
|
|
* will wait for space in the S/W FIFO.
|
|
*
|
|
* If the CAN hardware does not support a H/W FIFO then busy means that
|
|
* the hardware is actively sending the message and is guaranteed to
|
|
* become non-busy (i.e, dev_txready()) when the send transfer completes
|
|
* and can_txdone() is called. So the call to can_txdone() means that the
|
|
* transfer has completed and also that the hardware is ready to accept
|
|
* another transfer.
|
|
*
|
|
* If the CAN hardware supports a H/W FIFO, can_txdone() is not called
|
|
* when the tranfer is complete, but rather when the transfer is queued in
|
|
* the H/W FIFO. When the H/W FIFO becomes full, then dev_txready() will
|
|
* report false and the number of queued messages in the S/W FIFO will grow.
|
|
*
|
|
* There is no mechanism in this case to inform the upper half driver when
|
|
* the hardware is again available, when there is again space in the H/W
|
|
* FIFO. can_txdone() will not be called again. If the S/W FIFO becomes
|
|
* full, then the upper half driver will wait for space to become
|
|
* available, but there is no event to awaken it and the driver will hang.
|
|
*
|
|
* Enabling this feature adds support for the can_txready() interface.
|
|
* This function is called from the lower half driver's CAN interrupt
|
|
* handler each time a TX transfer completes. This is a sure indication
|
|
* that the H/W FIFO is no longer full. can_txready() will then awaken
|
|
* the can_write() logic and the hang condition is avoided.
|
|
*
|
|
* Input Parameters:
|
|
* dev - The specific CAN device
|
|
*
|
|
* Returned Value:
|
|
* OK on success; a negated errno on failure.
|
|
*
|
|
* Assumptions:
|
|
* Interrupts are disabled. This function may execute in the context of
|
|
* and interrupt handler.
|
|
*
|
|
****************************************************************************/
|
|
|
|
#ifdef CONFIG_CAN_TXREADY
|
|
int can_txready(FAR struct can_dev_s *dev)
|
|
{
|
|
int ret = -ENOENT;
|
|
|
|
caninfo("xmit head: %d queue: %d tail: %d waiters: %d\n",
|
|
dev->cd_xmit.tx_head, dev->cd_xmit.tx_queue, dev->cd_xmit.tx_tail,
|
|
dev->cd_ntxwaiters);
|
|
|
|
/* Verify that the xmit FIFO is not empty. This is safe because interrupts
|
|
* are always disabled when calling into can_xmit(); this cannot collide
|
|
* with ongoing activity from can_write().
|
|
*/
|
|
|
|
if (dev->cd_xmit.tx_head != dev->cd_xmit.tx_tail)
|
|
{
|
|
/* Is work already scheduled? */
|
|
|
|
if (work_available(&dev->cd_work))
|
|
{
|
|
/* Yes... schedule to perform can_txready() work on the worker
|
|
* thread. Although data structures are protected by disabling
|
|
* interrupts, the can_xmit() operations may involve semaphore
|
|
* operations and, hence, should not be done at the interrupt
|
|
* level.
|
|
*/
|
|
|
|
ret = work_queue(CANWORK, &dev->cd_work, can_txready_work, dev, 0);
|
|
}
|
|
else
|
|
{
|
|
ret = -EBUSY;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* There should not be any threads waiting for space in the S/W TX
|
|
* FIFO is it is empty.
|
|
*
|
|
* REVISIT: Assertion can fire in certain race conditions, i.e, when
|
|
* all waiters have been awakened but have not yet had a chance to
|
|
* decrement cd_ntxwaiters.
|
|
*/
|
|
|
|
//DEBUGASSERT(dev->cd_ntxwaiters == 0);
|
|
|
|
#if 0 /* REVISIT */
|
|
/* When the H/W FIFO has been emptied, we can disable further TX
|
|
* interrupts.
|
|
*
|
|
* REVISIT: The fact that the S/W FIFO is empty does not mean that
|
|
* the H/W FIFO is also empty. If we really want this to work this
|
|
* way, then we would probably need and additional parameter to tell
|
|
* us if the H/W FIFO is empty.
|
|
*/
|
|
|
|
dev_txint(dev, false);
|
|
#endif
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
#endif /* CONFIG_CAN_TXREADY */
|
|
#endif /* CONFIG_CAN */
|