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c0b4bd2f85
nuttx/drivers/can/can.c
dongjiuzhu d452a05910 pollnotify: we should send poll events before semaphore incrementes. 
There is a good case on sim platform:
When we input some cmd and click enter key to start application in terminal,
this context will change to application from IDLE loop. Althrough entey key '\r'
has been received to recv buffer and complete post semaphore of reader, but
pollnotify may not be called because context change. So when application run
poll function, because no events happend and poll enter wait, context will
again change to IDLE loop, this pollnotify of IDLE loop will run to send poll
events, poll function of applicaton will wake up. It's wrong!

Change-Id: I812a889f2e90781a9c3cb4b0251cccc4d32bebd1
Signed-off-by: dongjiuzhu <dongjiuzhu1@xiaomi.com>
2020-10-26 08:27:09 -03:00

1614 lines
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/****************************************************************************
* drivers/can/can.c
*
* Copyright (C) 2008-2009, 2011-2012, 2014-2015, 2017, 2019 Gregory Nutt.
* All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Copyright (C) 2016 Omni Hoverboards Inc. All rights reserved.
* Author: Paul Alexander Patience <paul-a.patience@polymtl.ca>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <assert.h>
#include <poll.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/signal.h>
#include <nuttx/fs/fs.h>
#include <nuttx/can/can.h>
#include <nuttx/kmalloc.h>
#ifdef CONFIG_CAN_TXREADY
# include <nuttx/wqueue.h>
#endif
#include <nuttx/irq.h>
#ifdef CONFIG_CAN
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
#ifdef CONFIG_CAN_TXREADY
# if !defined(CONFIG_SCHED_WORKQUEUE)
# error Work queue support required in this configuration
# undef CONFIG_CAN_TXREADY
# undef CONFIG_CAN_TXREADY_LOPRI
# undef CONFIG_CAN_TXREADY_HIPRI
# elif defined(CONFIG_CAN_TXREADY_LOPRI)
# undef CONFIG_CAN_TXREADY_HIPRI
# ifdef CONFIG_SCHED_LPWORK
# define CANWORK LPWORK
# else
# error Low priority work queue support required in this configuration
# undef CONFIG_CAN_TXREADY
# undef CONFIG_CAN_TXREADY_LOPRI
# endif
# elif defined(CONFIG_CAN_TXREADY_HIPRI)
# ifdef CONFIG_SCHED_HPWORK
# define CANWORK HPWORK
# else
# error High priority work queue support required in this configuration
# undef CONFIG_CAN_TXREADY
# undef CONFIG_CAN_TXREADY_HIPRI
# endif
# else
# error No work queue selection
# undef CONFIG_CAN_TXREADY
# endif
#endif
/* Timing Definitions *******************************************************/
#define HALF_SECOND_MSEC 500
#define HALF_SECOND_USEC 500000L
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* Semaphore helpers */
static int can_takesem(FAR sem_t *sem);
/* Poll helpers */
static void can_pollnotify(FAR struct can_dev_s *dev,
pollevent_t eventset);
/* CAN helpers */
static uint8_t can_dlc2bytes(uint8_t dlc);
#if 0 /* Not used */
static uint8_t can_bytes2dlc(uint8_t nbytes);
#endif
#ifdef CONFIG_CAN_TXREADY
static void can_txready_work(FAR void *arg);
#endif
/* Character driver methods */
static int can_open(FAR struct file *filep);
static int can_close(FAR struct file *filep);
static ssize_t can_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static int can_xmit(FAR struct can_dev_s *dev);
static ssize_t can_write(FAR struct file *filep,
FAR const char *buffer, size_t buflen);
static inline ssize_t can_rtrread(FAR struct can_dev_s *dev,
FAR struct canioc_rtr_s *rtr);
static int can_ioctl(FAR struct file *filep, int cmd,
unsigned long arg);
static int can_poll(FAR struct file *filep,
FAR struct pollfd *fds,
bool setup);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_canops =
{
can_open, /* open */
can_close, /* close */
can_read, /* read */
can_write, /* write */
NULL, /* seek */
can_ioctl, /* ioctl */
can_poll /* poll */
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
, NULL /* unlink */
#endif
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: can_takesem
****************************************************************************/
static int can_takesem(FAR sem_t *sem)
{
return nxsem_wait(sem);
}
/****************************************************************************
* Name: can_givesem
****************************************************************************/
#define can_givesem(sem) nxsem_post(sem)
/****************************************************************************
* Name: can_pollnotify
****************************************************************************/
static void can_pollnotify(FAR struct can_dev_s *dev, pollevent_t eventset)
{
FAR struct pollfd *fds;
int i;
for (i = 0; i < CONFIG_CAN_NPOLLWAITERS; i++)
{
fds = dev->cd_fds[i];
if (fds != NULL)
{
fds->revents |= fds->events & eventset;
if (fds->revents != 0)
{
caninfo("Report events: %02x\n", fds->revents);
nxsem_post(fds->sem);
}
}
}
}
/****************************************************************************
* Name: can_dlc2bytes
*
* Description:
* 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. But the codes 9 to 15 all imply a data field of 8 bytes with
* standard CAN. In CAN FD mode, the values 9 to 15 are encoded to values
* in the range 12 to 64.
*
* Input Parameters:
* dlc - the DLC value to convert to a byte count
*
* Returned Value:
* The number of bytes corresponding to the DLC value.
*
****************************************************************************/
static uint8_t can_dlc2bytes(uint8_t dlc)
{
if (dlc > 8)
{
#ifdef CONFIG_CAN_FD
switch (dlc)
{
case 9:
return 12;
case 10:
return 16;
case 11:
return 20;
case 12:
return 24;
case 13:
return 32;
case 14:
return 48;
default:
case 15:
return 64;
}
#else
return 8;
#endif
}
return dlc;
}
/****************************************************************************
* Name: can_bytes2dlc
*
* Description:
* 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. But the codes 9 to 15 all imply a data field of 8 bytes with
* standard CAN. In CAN FD mode, the values 9 to 15 are encoded to values
* in the range 12 to 64.
*
* Input Parameters:
* nbytes - the byte count to convert to a DLC value
*
* Returned Value:
* The encoded DLC value corresponding to at least that number of bytes.
*
****************************************************************************/
#if 0 /* Not used */
static uint8_t can_bytes2dlc(FAR struct sam_can_s *priv, uint8_t nbytes)
{
if (nbytes <= 8)
{
return nbytes;
}
#ifdef CONFIG_CAN_FD
else if (nbytes <= 12)
{
return 9;
}
else if (nbytes <= 16)
{
return 10;
}
else if (nbytes <= 20)
{
return 11;
}
else if (nbytes <= 24)
{
return 12;
}
else if (nbytes <= 32)
{
return 13;
}
else if (nbytes <= 48)
{
return 14;
}
else /* if (nbytes <= 64) */
{
return 15;
}
#else
else
{
return 8;
}
#endif
}
#endif
/****************************************************************************
* Name: can_txready_work
*
* Description:
* This function performs deferred processing from can_txready. See the
* description of can_txready below for additional information.
*
****************************************************************************/
#ifdef CONFIG_CAN_TXREADY
static void can_txready_work(FAR void *arg)
{
FAR struct can_dev_s *dev = (FAR struct can_dev_s *)arg;
irqstate_t flags;
int ret;
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. The following operations must
* be performed with interrupt disabled.
*/
flags = enter_critical_section();
if (dev->cd_xmit.tx_head != dev->cd_xmit.tx_tail)
{
/* Send the next message in the FIFO. */
ret = can_xmit(dev);
/* If the message was successfully queued in the H/W FIFO, then
* can_txdone() should have been called. If the S/W FIFO were
* full before then there should now be free space in the S/W FIFO.
*/
if (ret >= 0)
{
/* 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 */
can_givesem(&dev->cd_xmit.tx_sem);
}
}
}
leave_critical_section(flags);
}
#endif
static FAR struct can_reader_s *init_can_reader(FAR struct file *filep)
{
FAR struct can_reader_s *reader = kmm_zalloc(sizeof(struct can_reader_s));
DEBUGASSERT(reader != NULL);
reader->fifo.rx_head = 0;
reader->fifo.rx_tail = 0;
nxsem_init(&reader->fifo.rx_sem, 0, 1);
nxsem_set_protocol(&reader->fifo.rx_sem, SEM_PRIO_NONE);
filep->f_priv = reader;
return reader;
}
/****************************************************************************
* Name: can_open
*
* Description:
* This function is called whenever the CAN device is opened.
*
****************************************************************************/
static int can_open(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct can_dev_s *dev = inode->i_private;
irqstate_t flags;
int tmp;
int ret;
/* If the port is the middle of closing, wait until the close is finished */
ret = can_takesem(&dev->cd_closesem);
if (ret < 0)
{
return ret;
}
/* If this is the first time that the driver has been opened
* for this device, then perform hardware initialization.
*/
if (list_is_empty(&dev->cd_readers))
{
caninfo("ocount: %d\n", 0);
flags = enter_critical_section();
ret = dev_setup(dev);
if (ret >= 0)
{
/* Mark the FIFOs empty */
dev->cd_xmit.tx_head = 0;
dev->cd_xmit.tx_queue = 0;
dev->cd_xmit.tx_tail = 0;
/* Finally, Enable the CAN RX interrupt */
dev_rxint(dev, true);
}
list_add_head(&dev->cd_readers,
(FAR struct list_node *)init_can_reader(filep));
leave_critical_section(flags);
}
else
{
tmp = list_length(&dev->cd_readers);
caninfo("ocount: %d\n", tmp);
if (tmp >= 255)
{
/* Limit to no more than 255 opens */
ret = -EMFILE;
goto errout;
}
flags = enter_critical_section();
list_add_head(&dev->cd_readers,
(FAR struct list_node *)init_can_reader(filep));
leave_critical_section(flags);
}
errout:
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;
FAR struct list_node *node;
FAR struct list_node *tmp;
int ret;
#ifdef CONFIG_DEBUG_CAN_INFO
caninfo("ocount: %d\n", list_length(&dev->cd_readers));
#endif
ret = can_takesem(&dev->cd_closesem);
if (ret < 0)
{
return ret;
}
list_for_every_safe(&dev->cd_readers, node, tmp)
{
if (((FAR struct can_reader_s *)node) ==
((FAR struct can_reader_s *)filep->f_priv))
{
list_delete(node);
kmm_free(node);
break;
}
}
filep->f_priv = NULL;
/* Uninitialize the driver if there are no more readers */
if (!list_is_empty(&dev->cd_readers))
{
goto errout;
}
/* 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)
{
nxsig_usleep(HALF_SECOND_USEC);
}
/* And wait for the TX hardware FIFO to drain */
while (!dev_txempty(dev))
{
nxsig_usleep(HALF_SECOND_USEC);
}
/* 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 can_reader_s *reader = NULL;
FAR struct can_rxfifo_s *fifo;
size_t nread;
irqstate_t flags;
int ret = 0;
#ifdef CONFIG_CAN_ERRORS
FAR struct inode *inode = filep->f_inode;
FAR struct can_dev_s *dev = inode->i_private;
#endif
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 */
DEBUGASSERT(filep->f_priv != NULL);
reader = (FAR struct can_reader_s *)filep->f_priv;
fifo = &reader->fifo;
while (fifo->rx_head == fifo->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 */
ret = can_takesem(&fifo->rx_sem);
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 = &fifo->rx_buffer[fifo->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 (++fifo->rx_head >= CONFIG_CAN_FIFOSIZE)
{
fifo->rx_head = 0;
}
}
while (fifo->rx_head != fifo->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)
{
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)
{
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
****************************************************************************/
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;
FAR struct can_reader_s *reader = NULL;
pollevent_t eventset;
int ndx;
irqstate_t flags;
int ret;
int i;
/* Some sanity checking */
#ifdef CONFIG_DEBUG_FEATURES
if (dev == NULL || fds == NULL)
{
return -ENODEV;
}
#endif
flags = enter_critical_section();
DEBUGASSERT(filep->f_priv != NULL);
reader = (FAR struct can_reader_s *)filep->f_priv;
/* 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
*/
goto return_with_irqdisabled;
}
/* 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).
*/
do
{
ret = can_takesem(&reader->fifo.rx_sem);
}
while (ret < 0);
if (reader->fifo.rx_head != reader->fifo.rx_tail)
{
eventset |= fds->events & POLLIN;
}
can_givesem(&reader->fifo.rx_sem);
if (eventset != 0)
{
can_pollnotify(dev, eventset);
}
}
else if (fds->priv != NULL)
{
/* This is a request to tear down the poll */
FAR struct pollfd **slot = (FAR 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_with_irqdisabled:
leave_critical_section(flags);
return ret;
}
/****************************************************************************
* 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 */
list_initialize(&dev->cd_readers);
dev->cd_ntxwaiters = 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_set_protocol(&dev->cd_xmit.tx_sem, SEM_PRIO_NONE);
nxsem_init(&dev->cd_closesem, 0, 1);
nxsem_init(&dev->cd_pollsem, 0, 1);
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_set_protocol(&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;
FAR uint8_t *dest;
FAR struct list_node *node;
FAR struct list_node *tmp;
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.
*/
/* 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);
}
}
}
list_for_every_safe(&dev->cd_readers, node, tmp)
{
FAR struct can_reader_s *reader = (FAR struct can_reader_s *)node;
fifo = &reader->fifo;
nexttail = fifo->rx_tail + 1;
if (nexttail >= CONFIG_CAN_FIFOSIZE)
{
nexttail = 0;
}
/* Refuse the new data if the FIFO is full */
if (nexttail != fifo->rx_head)
{
int nbytes;
int sval;
/* 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);
memcpy(fifo->rx_buffer[fifo->rx_tail].cm_data, data, nbytes);
/* Increment the tail of the circular buffer */
fifo->rx_tail = nexttail;
/* Notify all poll/select waiters that they can read from the
* cd_recv buffer
*/
can_pollnotify(dev, POLLIN);
sval = 0;
if (nxsem_get_value(&fifo->rx_sem, &sval) < 0)
{
DEBUGASSERT(false);
#ifdef CONFIG_CAN_ERRORS
/* Report unspecified error */
dev->cd_error |= CAN_ERROR5_UNSPEC;
#endif
return -EINVAL;
}
/* Increment the counting semaphore. The maximum value should
* be CONFIG_CAN_FIFOSIZE -- one possible count for each allocated
* message buffer.
*/
if (sval <= 0)
{
can_givesem(&fifo->rx_sem);
}
errcode = OK;
}
#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 */
can_xmit(dev);
/* Notify all poll/select waiters that they can write to the cd_xmit
* buffer
*/
can_pollnotify(dev, POLLOUT);
/* 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;
}
}
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 queueing 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 transfer 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. However, an assertion would fire in certain
* race conditions, i.e, when all waiters have been awakened but
* have not yet had a chance to decrement cd_ntxwaiters.
*/
#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 */
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