/**************************************************************************** * drivers/can.c * * Copyright (C) 2008-2009, 2011-2012 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_CAN /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /* Debug ********************************************************************/ /* Non-standard debug that may be enabled just for testing CAN */ #ifdef CONFIG_DEBUG_CAN # define candbg dbg # define canvdbg vdbg # define canlldbg lldbg # define canllvdbg llvdbg #else # define candbg(x...) # define canvdbg(x...) # define canlldbg(x...) # define canllvdbg(x...) #endif /* Timing Definitions *******************************************************/ #define HALF_SECOND_MSEC 500 #define HALF_SECOND_USEC 500000L /**************************************************************************** * Private Type Definitions ****************************************************************************/ /**************************************************************************** * Private Function Prototypes ****************************************************************************/ 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 canioctl_rtr_s *rtr); static int can_ioctl(FAR struct file *filep, int cmd, unsigned long arg); /**************************************************************************** * Private Data ****************************************************************************/ static const struct file_operations g_canops = { can_open, /* open */ can_close, /* close */ can_read, /* read */ can_write, /* write */ 0, /* seek */ can_ioctl /* ioctl */ #ifndef CONFIG_DISABLE_POLL , 0 /* poll */ #endif }; /**************************************************************************** * Private Functions ****************************************************************************/ /************************************************************************************ * 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; uint8_t tmp; int ret = OK; canvdbg("ocount: %d\n", dev->cd_ocount); /* If the port is the middle of closing, wait until the close is finished */ if (sem_wait(&dev->cd_closesem) != OK) { ret = -errno; } else { /* Increment the count of references to the device. If this the first * time that the driver has been opened for this device, then initialize * the device. */ tmp = dev->cd_ocount + 1; if (tmp == 0) { /* More than 255 opens; uint8_t overflows to zero */ ret = -EMFILE; } else { /* Check if this is the first time that the driver has been opened. */ if (tmp == 1) { /* Yes.. perform one time hardware initialization. */ irqstate_t flags = irqsave(); ret = dev_setup(dev); if (ret == OK) { /* Mark the FIFOs empty */ dev->cd_xmit.cf_head = 0; dev->cd_xmit.cf_tail = 0; dev->cd_recv.cf_head = 0; dev->cd_recv.cf_tail = 0; /* Finally, Enable the CAN RX interrupt */ dev_rxint(dev, true); /* Save the new open count on success */ dev->cd_ocount = tmp; } irqrestore(flags); } } sem_post(&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 = OK; canvdbg("ocount: %d\n", dev->cd_ocount); if (sem_wait(&dev->cd_closesem) != OK) { ret = -errno; } else { /* 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--; sem_post(&dev->cd_closesem); } else { /* 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.cf_head != dev->cd_xmit.cf_tail) { #ifndef CONFIG_DISABLE_SIGNALS 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 usleep(HALF_SECOND_USEC); #else up_mdelay(HALF_SECOND_MSEC); #endif } /* Free the IRQ and disable the CAN device */ flags = irqsave(); /* Disable interrupts */ dev_shutdown(dev); /* Disable the CAN */ irqrestore(flags); sem_post(&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; canvdbg("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 = irqsave(); while (dev->cd_recv.cf_head == dev->cd_recv.cf_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 = sem_wait(&dev->cd_recv.cf_sem); if (ret < 0) { ret = -errno; 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.cf_buffer[dev->cd_recv.cf_head]; int msglen = CAN_MSGLEN(msg->cm_hdr); 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.cf_head >= CONFIG_CAN_FIFOSIZE) { dev->cd_recv.cf_head = 0; } } while (dev->cd_recv.cf_head != dev->cd_recv.cf_tail); /* All on the messages have bee transferred. Return the number of bytes * that were read. */ ret = nread; return_with_irqdisabled: irqrestore(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) { bool enable = false; int ret = OK; canllvdbg("xmit head: %d tail: %d\n", dev->cd_xmit.cf_head, dev->cd_xmit.cf_tail); /* Check if the xmit FIFO is empty */ if (dev->cd_xmit.cf_head != dev->cd_xmit.cf_tail) { /* Send the next message at the head of the FIFO */ ret = dev_send(dev, &dev->cd_xmit.cf_buffer[dev->cd_xmit.cf_head]); /* Make sure the TX done interrupts are enabled */ enable = (ret == OK ? true : false); } dev_txint(dev, enable); 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_fifo_s *fifo = &dev->cd_xmit; FAR struct can_msg_s *msg; bool empty = false; ssize_t nsent = 0; irqstate_t flags; int nexttail; int msglen; int ret = 0; canvdbg("buflen: %d\n", buflen); /* Interrupts must disabled throughout the following */ flags = irqsave(); /* Check if the TX FIFO was empty when we started. That is a clue that we have * to kick off a new TX sequence. */ empty = (fifo->cf_head == fifo->cf_tail); /* 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->cf_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->cf_head) { /* The transmit FIFO is full -- was non-blocking mode selected? */ if (filep->f_oflags & O_NONBLOCK) { if (nsent == 0) { ret = -EAGAIN; } else { ret = nsent; } goto return_with_irqdisabled; } /* If the FIFO was empty when we started, then we will have * start the XMIT sequence to clear the FIFO. */ if (empty) { can_xmit(dev); } /* Wait for a message to be sent */ do { DEBUGASSERT(dev->cd_ntxwaiters < 255); dev->cd_ntxwaiters++; ret = sem_wait(&fifo->cf_sem); dev->cd_ntxwaiters--; if (ret < 0 && errno != EINTR) { ret = -errno; goto return_with_irqdisabled; } } while (ret < 0); /* Re-check the FIFO state */ empty = (fifo->cf_head == fifo->cf_tail); } /* 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]; msglen = CAN_MSGLEN(msg->cm_hdr); memcpy(&fifo->cf_buffer[fifo->cf_tail], msg, msglen); /* Increment the tail of the circular buffer */ fifo->cf_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 of the XMIT sequence. */ if (empty) { can_xmit(dev); } /* Return the number of bytes that were sent */ ret = nsent; return_with_irqdisabled: irqrestore(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 canioctl_rtr_s *rtr) { FAR struct can_rtrwait_s *wait = NULL; irqstate_t flags; int i; int ret = -ENOMEM; /* Disable interrupts through this operation */ flags = irqsave(); /* Find an avaiable 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 == OK) { /* Then wait for the response */ ret = sem_wait(&wait->cr_sem); } } irqrestore(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; canvdbg("cmd: %d arg: %ld\n", cmd, arg); /* Handle built-in ioctl commands */ switch (cmd) { /* CANIOCTL_RTR: Send the remote transmission request and wait for the response. * Argument is a reference to struct canioctl_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 CANIOCTL_RTR: ret = can_rtrread(dev, (struct canioctl_rtr_s*)((uintptr_t)arg)); break; /* Not a "built-in" ioctl command.. perhaps it is unique to this device driver */ default: ret = dev_ioctl(dev, cmd, arg); break; } 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 */ dev->cd_ocount = 0; sem_init(&dev->cd_xmit.cf_sem, 0, 0); sem_init(&dev->cd_recv.cf_sem, 0, 0); sem_init(&dev->cd_closesem, 0, 1); for (i = 0; i < CONFIG_CAN_NPENDINGRTR; i++) { sem_init(&dev->cd_rtr[i].cr_sem, 0, 0); dev->cd_rtr[i].cr_msg = NULL; dev->cd_npendrtr--; } /* Initialize/reset the CAN hardware */ dev_reset(dev); /* Register the CAN device */ canvdbg("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 * * Parameters: * dev - CAN driver state structure * hdr - CAN message header * data - CAN message data (if DLC > 0) * * Assumptions: * CAN interrupts are disabled. * ************************************************************************************/ int can_receive(FAR struct can_dev_s *dev, uint16_t hdr, FAR uint8_t *data) { FAR struct can_fifo_s *fifo = &dev->cd_recv; FAR uint8_t *dest; int nexttail; int err = -ENOMEM; int i; canllvdbg("ID: %d DLC: %d\n", CAN_ID(hdr), CAN_DLC(hdr)); /* Check if adding this new message would over-run the drivers ability to enqueue * read data. */ nexttail = fifo->cf_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 && CAN_ID(hdr) == rtr->cr_id) { /* We have the response... copy the data to the user's buffer */ msg->cm_hdr = hdr; for (i = 0, dest = msg->cm_data; i < CAN_DLC(hdr); i++) { *dest++ = *data++; } /* Mark the entry unused */ rtr->cr_msg = NULL; /* And restart the waiting thread */ sem_post(&rtr->cr_sem); } } } /* Refuse the new data if the FIFO is full */ if (nexttail != fifo->cf_head) { /* Add the new, decoded CAN message at the tail of the FIFO */ fifo->cf_buffer[fifo->cf_tail].cm_hdr = hdr; for (i = 0, dest = fifo->cf_buffer[fifo->cf_tail].cm_data; i < CAN_DLC(hdr); i++) { *dest++ = *data++; } /* Increment the tail of the circular buffer */ fifo->cf_tail = nexttail; /* The increment the counting semaphore. The maximum value should be * CONFIG_CAN_FIFOSIZE -- one possible count for each allocated message buffer. */ sem_post(&fifo->cf_sem); err = OK; } return err; } /************************************************************************************ * Name: can_txdone * * Description: * Called from the CAN interrupt handler at the completion of a send operation. * * Parameters: * dev - The specific CAN device * hdr - The 16-bit CAN header * data - An array contain the CAN data. * * Return: * OK on success; a negated errno on failure. * ************************************************************************************/ int can_txdone(FAR struct can_dev_s *dev) { int ret = -ENOENT; canllvdbg("xmit head: %d tail: %d\n", dev->cd_xmit.cf_head, dev->cd_xmit.cf_tail); /* Verify that the xmit FIFO is not empty */ if (dev->cd_xmit.cf_head != dev->cd_xmit.cf_tail) { /* Remove the message at the head of the xmit FIFO */ if (++dev->cd_xmit.cf_head >= CONFIG_CAN_FIFOSIZE) { dev->cd_xmit.cf_head = 0; } /* Send the next message in the FIFO */ ret = can_xmit(dev); /* Are there any threads waiting for space in the TX FIFO? */ if (ret == OK && dev->cd_ntxwaiters > 0) { /* Yes.. Inform them that new xmit space is available */ ret = sem_post(&dev->cd_xmit.cf_sem); } } return ret; } #endif /* CONFIG_CAN */