Add a generic CAN driver

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@660 42af7a65-404d-4744-a932-0658087f49c3

2 files changed, 737 insertions, 1 deletions

diff --git a/nuttx/drivers/Makefile b/nuttx/drivers/Makefile
index 8b97332b5..00ceef1f0 100644
--- a/nuttx/drivers/Makefile
+++ b/nuttx/drivers/Makefile
@@ -44,7 +44,7 @@ AOBJS		= $(ASRCS:.S=$(OBJEXT))
 
 CSRCS		=
 ifneq ($(CONFIG_NFILE_DESCRIPTORS),0)
-CSRCS		+= dev_null.c dev_zero.c serial.c lowconsole.c
+CSRCS		+= dev_null.c dev_zero.c serial.c lowconsole.c can.c
 endif
 CSRCS		+= $(NET_CSRCS)
 COBJS		= $(CSRCS:.c=$(OBJEXT))
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;
+}
+