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author | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2008-02-08 00:56:16 +0000 |
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committer | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2008-02-08 00:56:16 +0000 |
commit | ebff820250129b6361ff9de635578e07d11fe16c (patch) | |
tree | 17edcb9084f355864a0ba29b8eb9dd17a071a416 /nuttx/drivers/can.c | |
parent | 7aa2d7ac7678b5b7ee7dc2a817f123f0b8a366b4 (diff) | |
download | px4-nuttx-ebff820250129b6361ff9de635578e07d11fe16c.tar.gz px4-nuttx-ebff820250129b6361ff9de635578e07d11fe16c.tar.bz2 px4-nuttx-ebff820250129b6361ff9de635578e07d11fe16c.zip |
Add a generic CAN driver
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@660 42af7a65-404d-4744-a932-0658087f49c3
Diffstat (limited to 'nuttx/drivers/can.c')
-rw-r--r-- | nuttx/drivers/can.c | 736 |
1 files changed, 736 insertions, 0 deletions
diff --git a/nuttx/drivers/can.c b/nuttx/drivers/can.c new file mode 100644 index 000000000..84db1eacf --- /dev/null +++ b/nuttx/drivers/can.c @@ -0,0 +1,736 @@ +/**************************************************************************** + * drivers/can.c + * + * Copyright (C) 2008 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * 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. + * + ****************************************************************************/ + +/**************************************************************************** + * Compilation Switches + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <sys/types.h> +#include <unistd.h> +#include <string.h> +#include <semaphore.h> +#include <fcntl.h> +#include <errno.h> +#include <debug.h> + +#include <nuttx/fs.h> +#include <nuttx/can.h> + +#include <arch/irq.h> + +/**************************************************************************** + * Definitions + ****************************************************************************/ + +/**************************************************************************** + * 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 + ****************************************************************************/ + +struct file_operations g_canops = +{ + can_open, /* open */ + can_close, /* close */ + can_read, /* read */ + can_write, /* write */ + 0, /* seek */ + can_ioctl /* ioctl */ +}; + +/**************************************************************************** + * 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; + int ret = OK; + + /* 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. + */ + + if (++dev->cd_ocount == 1) + { + irqstate_t flags = irqsave(); + + /* Configure hardware interrupts */ + + 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 CAN interrupt */ + + dev_rxint(dev, TRUE); + } + 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; + + 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(500*1000); +#else + up_mdelay(500); +#endif + } + + /* And wait for the TX hardware FIFO to drain */ + + while (!dev_txempty(dev)) + { +#ifndef CONFIG_DISABLE_SIGNALS + usleep(500*1000); +#else + up_mdelay(500); +#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; + + /* 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 (ret + 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) +{ + boolean enable = FALSE; + int ret = OK; + + /* Check if the xmit FIFO is empty */ + + if (dev->cd_xmit.cf_head != dev->cd_xmit.cf_head) + { + /* 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; + boolean empty = FALSE; + ssize_t nsent = 0; + irqstate_t flags; + int nexttail; + int msglen; + int ret = 0; + + /* 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 + { + ret = sem_wait(&fifo->cf_sem); + 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; + + /* 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 + */ + + case CANIOCTL_RTR: + ret = can_rtrread(dev, (struct canioctl_rtr_s*)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 */ + + dbg("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 hdr, FAR ubyte *data) +{ + FAR struct can_fifo_s *fifo = &dev->cd_recv; + FAR ubyte *dest; + int nexttail; + int err = -ENOMEM; + int i; + + /* 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 specifi 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; + + /* Verify that the xmit FIFO is not empty */ + + if (dev->cd_xmit.cf_head != dev->cd_xmit.cf_head) + { + /* 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); + if (ret == OK) + { + /* Inform any waiting threads that new xmit space is available */ + + ret = sem_post(&dev->cd_xmit.cf_sem); + } + } + return ret; +} + |