/************************************************************************************
* arch/arm/src/lpc17xx/lpc17_can.c
*
* Copyright (C) 2011 Li Zhuoyi. All rights reserved.
* Copyright (C) 2012 Gregory Nutt. All rights reserved.
* Authors:
* Li Zhuoyi <lzyy.cn@gmail.com>
* Gregory Nutt <gnutt@nuttx.org>
* History:
* 2011-07-12: Initial version (Li Zhuoyi)
* 2011-08-03: Support CAN1/CAN2 (Li Zhuoyi)
* 2012-01-02: Add support for CAN loopback mode (Gregory Nutt)
*
* This file is a part of NuttX:
*
* Copyright (C) 2010 Gregory Nutt. All rights reserved.
*
* 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.
*
************************************************************************************/
#include <nuttx/config.h>
#include <stdio.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <semaphore.h>
#include <errno.h>
#include <debug.h>
#include <arch/board/board.h>
#include <nuttx/arch.h>
#include <nuttx/can.h>
#include "up_internal.h"
#include "up_arch.h"
#include "chip.h"
#include "lpc17_internal.h"
#include "lpc17_syscon.h"
#include "lpc17_pinconn.h"
#include "lpc17_can.h"
#if defined(CONFIG_LPC17_CAN1) || defined(CONFIG_LPC17_CAN2)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
#ifdef CONFIG_LPC17_CAN1
/* A CAN bit rate must be provided */
# ifndef CONFIG_CAN1_BAUD
# error "CONFIG_CAN1_BAUD is not defined"
# endif
/* If no divsor is provided, use a divisor of 4 */
# ifndef CONFIG_CAN1_DIVISOR
# define CONFIG_CAN1_DIVISOR 4
# endif
/* Get the SYSCON_PCLKSEL value for CAN1 the implements this divisor */
# if CONFIG_CAN1_DIVISOR == 1
# define CAN1_CCLK_DIVISOR SYSCON_PCLKSEL_CCLK
# elif CONFIG_CAN1_DIVISOR == 2
# define CAN1_CCLK_DIVISOR SYSCON_PCLKSEL_CCLK2
# elif CONFIG_CAN1_DIVISOR == 4
# define CAN1_CCLK_DIVISOR SYSCON_PCLKSEL_CCLK4
# elif CONFIG_CAN1_DIVISOR == 6
# define CAN1_CCLK_DIVISOR SYSCON_PCLKSEL_CCLK6
# else
# error "Unsupported value of CONFIG_CAN1_DIVISOR"
# endif
#endif
#ifdef CONFIG_LPC17_CAN2
/* A CAN bit rate must be provided */
# ifndef CONFIG_CAN2_BAUD
# error "CONFIG_CAN2_BAUD is not defined"
# endif
/* If no divsor is provided, use a divisor of 4 */
# ifndef CONFIG_CAN2_DIVISOR
# define CONFIG_CAN2_DIVISOR 4
# endif
/* Get the SYSCON_PCLKSEL value for CAN2 the implements this divisor */
# if CONFIG_CAN2_DIVISOR == 1
# define CAN2_CCLK_DIVISOR SYSCON_PCLKSEL_CCLK
# elif CONFIG_CAN2_DIVISOR == 2
# define CAN2_CCLK_DIVISOR SYSCON_PCLKSEL_CCLK2
# elif CONFIG_CAN2_DIVISOR == 4
# define CAN2_CCLK_DIVISOR SYSCON_PCLKSEL_CCLK4
# elif CONFIG_CAN2_DIVISOR == 6
# define CAN2_CCLK_DIVISOR SYSCON_PCLKSEL_CCLK6
# else
# error "Unsupported value of CONFIG_CAN2_DIVISOR"
# endif
#endif
/* Debug ********************************************************************/
/* Non-standard debug that may be enabled just for testing CAN */
#if !defined(CONFIG_DEBUG) || !defined(CONFIG_DEBUG_CAN)
# undef CONFIG_CAN_REGDEBUG
#endif
#ifdef CONFIG_DEBUG_CAN
# ifdef CONFIG_CAN_REGDEBUG
# define candbg lldbg
# define canvdbg llvdbg
# else
# define candbg dbg
# define canvdbg vdbg
# endif
# define canlldbg lldbg
# define canllvdbg llvdbg
#else
# define candbg(x...)
# define canvdbg(x...)
# define canlldbg(x...)
# define canllvdbg(x...)
#endif
/* Timing *******************************************************************/
/* CAN clocking is provided at CCLK divided by the configured divisor */
#define CAN_CLOCK_FREQUENCY(d) ((uint32_t)LPC17_CCLK / (uint32_t)(d))
/****************************************************************************
* Private Types
****************************************************************************/
struct up_dev_s
{
uint8_t port; /* CAN port number */
uint8_t divisor; /* CCLK divisor (numeric value) */
uint32_t baud; /* Configured baud */
uint32_t base; /* CAN register base address */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* CAN Register access */
#ifdef CONFIG_CAN_REGDEBUG
static void can_printreg(uint32_t addr, uint32_t value);
#endif
static uint32_t can_getreg(struct up_dev_s *priv, int offset);
static void can_putreg(struct up_dev_s *priv, int offset, uint32_t value);
#ifdef CONFIG_CAN_REGDEBUG
static uint32_t can_getcommon(uint32_t addr);
static void can_putcommon(uint32_t addr, uint32_t value);
#else
# define can_getcommon(addr) getreg32(addr)
# define can_putcommon(addr, value) putreg32(value, addr)
#endif
/* CAN methods */
static void can_reset(FAR struct can_dev_s *dev);
static int can_setup(FAR struct can_dev_s *dev);
static void can_shutdown(FAR struct can_dev_s *dev);
static void can_rxint(FAR struct can_dev_s *dev, bool enable);
static void can_txint(FAR struct can_dev_s *dev, bool enable);
static int can_ioctl(FAR struct can_dev_s *dev, int cmd, unsigned long arg);
static int can_remoterequest(FAR struct can_dev_s *dev, uint16_t id);
static int can_send(FAR struct can_dev_s *dev, FAR struct can_msg_s *msg);
static bool can_txempty(FAR struct can_dev_s *dev);
/* CAN interrupts */
static void can_interrupt(FAR struct can_dev_s *dev);
static int can12_interrupt(int irq, void *context);
/* Initialization */
static int can_bittiming(struct up_dev_s *priv);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct can_ops_s g_canops =
{
.co_reset = can_reset,
.co_setup = can_setup,
.co_shutdown = can_shutdown,
.co_rxint = can_rxint,
.co_txint = can_txint,
.co_ioctl = can_ioctl,
.co_remoterequest = can_remoterequest,
.co_send = can_send,
.co_txempty = can_txempty,
};
#ifdef CONFIG_LPC17_CAN1
static struct up_dev_s g_can1priv =
{
.port = 1,
.divisor = CONFIG_CAN1_DIVISOR,
.baud = CONFIG_CAN1_BAUD,
.base = LPC17_CAN1_BASE,
};
static struct can_dev_s g_can1dev =
{
.cd_ops = &g_canops,
.cd_priv = &g_can1priv,
};
#endif
#ifdef CONFIG_LPC17_CAN2
static struct up_dev_s g_can2priv =
{
.port = 2,
.divisor = CONFIG_CAN2_DIVISOR,
.baud = CONFIG_CAN2_BAUD,
.base = LPC17_CAN2_BASE,
};
static struct can_dev_s g_can2dev =
{
.cd_ops = &g_canops,
.cd_priv = &g_can2priv,
};
#endif
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: can_printreg
*
* Description:
* Print the value read from a register.
*
* Input Parameters:
* addr - The register address
* value - The register value
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_CAN_REGDEBUG
static void can_printreg(uint32_t addr, uint32_t value)
{
static uint32_t prevaddr = 0;
static uint32_t preval = 0;
static uint32_t count = 0;
/* Is this the same value that we read from the same register last time?
* Are we polling the register? If so, suppress some of the output.
*/
if (addr == prevaddr && value == preval)
{
if (count == 0xffffffff || ++count > 3)
{
if (count == 4)
{
lldbg("...\n");
}
return;
}
}
/* No this is a new address or value */
else
{
/* Did we print "..." for the previous value? */
if (count > 3)
{
/* Yes.. then show how many times the value repeated */
lldbg("[repeats %d more times]\n", count-3);
}
/* Save the new address, value, and count */
prevaddr = addr;
preval = value;
count = 1;
}
/* Show the register value read */
lldbg("%08x->%08x\n", addr, value);
}
#endif
/****************************************************************************
* Name: can_getreg
*
* Description:
* Read the value of an CAN1/2 register.
*
* Input Parameters:
* priv - A reference to the CAN block status
* offset - The offset to the register to read
*
* Returned Value:
*
****************************************************************************/
#ifdef CONFIG_CAN_REGDEBUG
static uint32_t can_getreg(struct up_dev_s *priv, int offset)
{
uint32_t addr;
uint32_t value;
/* Read the value from the register */
addr = priv->base + offset;
value = getreg32(addr);
can_printreg(addr, value);
return value;
}
#else
static uint32_t can_getreg(struct up_dev_s *priv, int offset)
{
return getreg32(priv->base + offset);
}
#endif
/****************************************************************************
* Name: can_putreg
*
* Description:
* Set the value of an CAN1/2 register.
*
* Input Parameters:
* priv - A reference to the CAN block status
* offset - The offset to the register to write
* value - The value to write to the register
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_CAN_REGDEBUG
static void can_putreg(struct up_dev_s *priv, int offset, uint32_t value)
{
uint32_t addr = priv->base + offset;
/* Show the register value being written */
lldbg("%08x<-%08x\n", addr, value);
/* Write the value */
putreg32(value, addr);
}
#else
static void can_putreg(struct up_dev_s *priv, int offset, uint32_t value)
{
putreg32(value, priv->base + offset);
}
#endif
/****************************************************************************
* Name: can_getcommon
*
* Description:
* Get the value of common register.
*
* Input Parameters:
* addr - The address of the register to read
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_CAN_REGDEBUG
static uint32_t can_getcommon(uint32_t addr)
{
uint32_t value;
/* Read the value from the register */
value = getreg32(addr);
can_printreg(addr, value);
return value;
}
#endif
/****************************************************************************
* Name: can_putcommon
*
* Description:
* Set the value of common register.
*
* Input Parameters:
* addr - The address of the register to write
* value - The value to write to the register
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_CAN_REGDEBUG
static void can_putcommon(uint32_t addr, uint32_t value)
{
/* Show the register value being written */
lldbg("%08x<-%08x\n", addr, value);
/* Write the value */
putreg32(value, addr);
}
#endif
/****************************************************************************
* Name: can_reset
*
* Description:
* Reset the CAN device. Called early to initialize the hardware. This
* function is called, before can_setup() and on error conditions.
*
* Input Parameters:
* dev - An instance of the "upper half" can driver state structure.
*
* Returned Value:
* None
*
****************************************************************************/
static void can_reset(FAR struct can_dev_s *dev)
{
FAR struct up_dev_s *priv = (FAR struct up_dev_s *)dev->cd_priv;
uint32_t baud;
int ret;
irqstate_t flags;
canvdbg("CAN%d\n", priv->port);
flags = irqsave();
/* Disable the CAN and stop ongong transmissions */
can_putreg(priv, LPC17_CAN_MOD_OFFSET, CAN_MOD_RM); /* Enter Reset Mode */
can_putreg(priv, LPC17_CAN_IER_OFFSET, 0); /* Disable interrupts */
can_putreg(priv, LPC17_CAN_GSR_OFFSET, 0); /* Clear status bits */
can_putreg(priv, LPC17_CAN_CMR_OFFSET, CAN_CMR_AT); /* Abort transmission */
/* Set bit timing */
ret = can_bittiming(priv);
if (ret != OK)
{
candbg("ERROR: Failed to set bit timing: %d\n", ret);
}
/* Restart the CAN */
#ifdef CONFIG_CAN_LOOPBACK
can_putreg(priv, LPC17_CAN_MOD_OFFSET, CAN_MOD_STM); /* Leave Reset Mode, enter Test Mode */
#else
can_putreg(priv, LPC17_CAN_MOD_OFFSET, 0); /* Leave Reset Mode */
#endif
can_putcommon(LPC17_CANAF_AFMR, CANAF_AFMR_ACCBP); /* All RX messages accepted */
irqrestore(flags);
}
/****************************************************************************
* Name: can_setup
*
* Description:
* Configure the CAN. This method is called the first time that the CAN
* device is opened. This will occur when the port is first opened.
* This setup includes configuring and attaching CAN interrupts.
* All CAN interrupts are disabled upon return.
*
* Input Parameters:
* dev - An instance of the "upper half" can driver state structure.
*
* Returned Value:
* Zero on success; a negated errno on failure
*
****************************************************************************/
static int can_setup(FAR struct can_dev_s *dev)
{
#ifdef CONFIG_DEBUG_CAN
FAR struct up_dev_s *priv = (FAR struct up_dev_s *)dev->cd_priv;
#endif
int ret;
canvdbg("CAN%d\n", priv->port);
ret = irq_attach(LPC17_IRQ_CAN, can12_interrupt);
if (ret == OK)
{
up_enable_irq(LPC17_IRQ_CAN);
}
return ret;
}
/****************************************************************************
* Name: can_shutdown
*
* Description:
* Disable the CAN. This method is called when the CAN device is closed.
* This method reverses the operation the setup method.
*
* Input Parameters:
* dev - An instance of the "upper half" can driver state structure.
*
* Returned Value:
* None
*
****************************************************************************/
static void can_shutdown(FAR struct can_dev_s *dev)
{
#ifdef CONFIG_DEBUG_CAN
FAR struct up_dev_s *priv = (FAR struct up_dev_s *)dev->cd_priv;
canvdbg("CAN%d\n", priv->port);
#endif
up_disable_irq(LPC17_IRQ_CAN);
irq_detach(LPC17_IRQ_CAN);
}
/****************************************************************************
* Name: can_rxint
*
* Description:
* Call to enable or disable RX interrupts.
*
* Input Parameters:
* dev - An instance of the "upper half" can driver state structure.
*
* Returned Value:
* None
*
****************************************************************************/
static void can_rxint(FAR struct can_dev_s *dev, bool enable)
{
FAR struct up_dev_s *priv = (FAR struct up_dev_s *)dev->cd_priv;
uint32_t regval;
irqstate_t flags;
canvdbg("CAN%d enable: %d\n", priv->port, enable);
/* The EIR register is also modifed from the interrupt handler, so we have
* to protect this code section.
*/
flags = irqsave();
regval = can_getreg(priv, LPC17_CAN_IER_OFFSET);
if (enable)
{
regval |= CAN_IER_RIE;
}
else
{
regval &= ~CAN_IER_RIE;
}
can_putreg(priv, LPC17_CAN_IER_OFFSET, regval);
irqrestore(flags);
}
/****************************************************************************
* Name: can_txint
*
* Description:
* Call to enable or disable TX interrupts.
*
* Input Parameters:
* dev - An instance of the "upper half" can driver state structure.
*
* Returned Value:
* None
*
****************************************************************************/
static void can_txint(FAR struct can_dev_s *dev, bool enable)
{
FAR struct up_dev_s *priv = (FAR struct up_dev_s *)dev->cd_priv;
uint32_t regval;
irqstate_t flags;
canvdbg("CAN%d enable: %d\n", priv->port, enable);
/* Only disabling of the TX interrupt is supported here. The TX interrupt
* is automatically enabled just before a message is sent in order to avoid
* lost TX interrupts.
*/
if (!enable)
{
/* TX interrupts are also disabled from the interrupt handler, so we have
* to protect this code section.
*/
flags = irqsave();
/* Disable all TX interrupts */
regval = can_getreg(priv, LPC17_CAN_IER_OFFSET);
regval &= ~(CAN_IER_TIE1 | CAN_IER_TIE2 | CAN_IER_TIE3);
can_putreg(priv, LPC17_CAN_IER_OFFSET, regval);
irqrestore(flags);
}
}
/****************************************************************************
* Name: can_ioctl
*
* Description:
* All ioctl calls will be routed through this method
*
* Input Parameters:
* dev - An instance of the "upper half" can driver state structure.
*
* Returned Value:
* Zero on success; a negated errno on failure
*
****************************************************************************/
static int can_ioctl(FAR struct can_dev_s *dev, int cmd, unsigned long arg)
{
dbg("Fix me:Not Implemented\n");
return 0;
}
/****************************************************************************
* Name: can_remoterequest
*
* Description:
* Send a remote request
*
* Input Parameters:
* dev - An instance of the "upper half" can driver state structure.
*
* Returned Value:
* Zero on success; a negated errno on failure
*
****************************************************************************/
static int can_remoterequest(FAR struct can_dev_s *dev, uint16_t id)
{
dbg("Fix me:Not Implemented\n");
return 0;
}
/****************************************************************************
* Name: can_send
*
* Description:
* Send one can message.
*
* One CAN-message consists of a maximum of 10 bytes. A message is
* composed of at least the first 2 bytes (when there are no data bytes).
*
* Byte 0: Bits 0-7: Bits 3-10 of the 11-bit CAN identifier
* Byte 1: Bits 5-7: Bits 0-2 of the 11-bit CAN identifier
* Bit 4: Remote Tranmission Request (RTR)
* Bits 0-3: Data Length Code (DLC)
* Bytes 2-10: CAN data
*
* Input Parameters:
* dev - An instance of the "upper half" can driver state structure.
*
* Returned Value:
* Zero on success; a negated errno on failure
*
****************************************************************************/
static int can_send(FAR struct can_dev_s *dev, FAR struct can_msg_s *msg)
{
FAR struct up_dev_s *priv = (FAR struct up_dev_s *)dev->cd_priv;
uint32_t tid = CAN_ID(msg->cm_hdr);
uint32_t tfi = CAN_DLC(msg->cm_hdr) << 16;
uint32_t regval;
irqstate_t flags;
int ret = OK;
canvdbg("CAN%d ID: %d DLC: %d\n",
priv->port, CAN_ID(msg->cm_hdr), CAN_DLC(msg->cm_hdr));
if (CAN_RTR(msg->cm_hdr))
{
tfi |= CAN_TFI_RTR;
}
flags = irqsave();
/* Pick a transmit buffer */
regval = can_getreg(priv, LPC17_CAN_SR_OFFSET);
if ((regval & CAN_SR_TBS1) != 0)
{
/* Set up the transfer */
can_putreg(priv, LPC17_CAN_TFI1_OFFSET, tfi);
can_putreg(priv, LPC17_CAN_TID1_OFFSET, tid);
can_putreg(priv, LPC17_CAN_TDA1_OFFSET, *(uint32_t *)&msg->cm_data[0]);
can_putreg(priv, LPC17_CAN_TDB1_OFFSET, *(uint32_t *)&msg->cm_data[4]);
/* Send the message */
#ifdef CONFIG_CAN_LOOPBACK
can_putreg(priv, LPC17_CAN_CMR_OFFSET, CAN_CMR_STB1 | CAN_CMR_SRR);
#else
can_putreg(priv, LPC17_CAN_CMR_OFFSET, CAN_CMR_STB1 | CAN_CMR_TR);
#endif
/* Tell the caller that the transfer is done. It isn't, but we have
* more transmit buffers and this can speed things up.
*/
can_txdone(dev);
}
else if ((regval & CAN_SR_TBS2) != 0)
{
/* Set up the transfer */
can_putreg(priv, LPC17_CAN_TFI2_OFFSET, tfi);
can_putreg(priv, LPC17_CAN_TID2_OFFSET, tid);
can_putreg(priv, LPC17_CAN_TDA2_OFFSET, *(uint32_t *)&msg->cm_data[0]);
can_putreg(priv, LPC17_CAN_TDB2_OFFSET, *(uint32_t *)&msg->cm_data[4]);
/* Send the message */
#ifdef CONFIG_CAN_LOOPBACK
can_putreg(priv, LPC17_CAN_CMR_OFFSET, CAN_CMR_STB2 | CAN_CMR_SRR);
#else
can_putreg(priv, LPC17_CAN_CMR_OFFSET, CAN_CMR_STB2 | CAN_CMR_TR);
#endif
/* Tell the caller that the transfer is done. It isn't, but we have
* more transmit buffers and this can speed things up.
*/
can_txdone(dev);
}
else if ((regval & CAN_SR_TBS3) != 0)
{
/* We have no more buffers. We will make the caller wait. First, make
* sure that all buffer 3 interrupts are enabled BEFORE sending the
* message. The TX interrupt is generated TBSn bit in CANxSR goes from 0
* to 1 when the TIEn bit in CANxIER is 1. If we don't enable it now,
* we will miss the TIE3 interrupt. We enable ALL TIE interrupts here
* because we don't care which one finishes: When first one finishes it
* means that a transmit buffer is again available.
*
* NOTE: The IER is also modified from the interrupt handler, but the
* following is safe because interrupts are disabled here.
*/
regval = can_getreg(priv, LPC17_CAN_IER_OFFSET);
regval |= (CAN_IER_TIE1 | CAN_IER_TIE2 | CAN_IER_TIE3);
can_putreg(priv, LPC17_CAN_IER_OFFSET, regval);
/* Set up the transfer */
can_putreg(priv, LPC17_CAN_TFI3_OFFSET, tfi);
can_putreg(priv, LPC17_CAN_TID3_OFFSET, tid);
can_putreg(priv, LPC17_CAN_TDA3_OFFSET, *(uint32_t *)&msg->cm_data[0]);
can_putreg(priv, LPC17_CAN_TDB3_OFFSET, *(uint32_t *)&msg->cm_data[4]);
/* Send the message */
#ifdef CONFIG_CAN_LOOPBACK
can_putreg(priv, LPC17_CAN_CMR_OFFSET, CAN_CMR_STB3 | CAN_CMR_SRR);
#else
can_putreg(priv, LPC17_CAN_CMR_OFFSET, CAN_CMR_STB3 | CAN_CMR_TR);
#endif
}
else
{
candbg("No available transmission buffer, SR: %08x\n", regval);
ret = -EBUSY;
}
irqrestore(flags);
return ret;
}
/****************************************************************************
* Name: can_txempty
*
* Description:
* Return true if all message have been sent. If for example, the CAN
* hardware implements FIFOs, then this would mean the transmit FIFO is
* empty. This method is called when the driver needs to make sure that
* all characters are "drained" from the TX hardware before calling
* co_shutdown().
*
* Input Parameters:
* dev - An instance of the "upper half" can driver state structure.
*
* Returned Value:
* Zero on success; a negated errno on failure
*
****************************************************************************/
static bool can_txempty(FAR struct can_dev_s *dev)
{
FAR struct up_dev_s *priv = (FAR struct up_dev_s *)dev->cd_priv;
uint32_t regval = can_getreg(priv, LPC17_CAN_GSR_OFFSET);
return ((regval & CAN_GSR_TBS) != 0);
}
/****************************************************************************
* Name: can_interrupt
*
* Description:
* CAN1/2 RX/TX interrupt handler
*
* Input Parameters:
* dev - An instance of the "upper half" can driver state structure.
*
* Returned Value:
* Zero on success; a negated errno on failure
*
****************************************************************************/
static void can_interrupt(FAR struct can_dev_s *dev)
{
FAR struct up_dev_s *priv = (FAR struct up_dev_s *)dev->cd_priv;
uint32_t data[2];
uint32_t rfs;
uint32_t rid;
uint32_t regval;
uint16_t hdr;
uint16_t id;
uint16_t dlc;
uint16_t rtr;
/* Read the interrupt and capture register (also clearing most status bits) */
regval = can_getreg(priv, LPC17_CAN_ICR_OFFSET);
canllvdbg("CAN%d ICR: %08x\n", priv->port, regval);
/* Check for a receive interrupt */
if ((regval & CAN_ICR_RI) != 0)
{
rfs = can_getreg(priv, LPC17_CAN_RFS_OFFSET);
rid = can_getreg(priv, LPC17_CAN_RID_OFFSET);
data[0] = can_getreg(priv, LPC17_CAN_RDA_OFFSET);
data[1] = can_getreg(priv, LPC17_CAN_RDB_OFFSET);
/* Release the receive buffer */
can_putreg(priv, LPC17_CAN_CMR_OFFSET, CAN_CMR_RRB);
/* Construct the CAN header */
id = rid & CAN_RID_ID11_MASK;
dlc = (rfs & CAN_RFS_DLC_MASK) >> CAN_RFS_DLC_SHIFT;
rtr = ((rfs & CAN_RFS_RTR) != 0);
hdr = CAN_HDR(id, rtr, dlc);
/* Process the received CAN packet */
can_receive(dev, hdr, (uint8_t *)data);
}
/* Check for a transmit interrupt from buffer 1, 2, or 3 meaning that at
* least one TX is complete and that at least one TX buffer is available.
*/
if ((regval & (CAN_ICR_TI1 | CAN_ICR_TI2 |CAN_ICR_TI3)) != 0)
{
/* Disable all further TX interrupts */
regval = can_getreg(priv, LPC17_CAN_IER_OFFSET);
regval &= ~(CAN_IER_TIE1 | CAN_IER_TIE2 | CAN_IER_TIE3);
can_putreg(priv, LPC17_CAN_IER_OFFSET, regval);
/* Indicate that the TX is done and a new TX buffer is available */
can_txdone(&g_can1dev);
}
}
/****************************************************************************
* Name: can12_interrupt
*
* Description:
* CAN interrupt handler. There is a single interrupt for both CAN1 and
* CAN2.
*
* Input Parameters:
* irq - The IRQ number of the interrupt.
* context - The register state save array at the time of the interrupt.
*
* Returned Value:
* Zero on success; a negated errno on failure
*
****************************************************************************/
static int can12_interrupt(int irq, void *context)
{
/* Handle CAN1/2 interrupts */
canllvdbg("irq: %d\n", irq);
#ifdef CONFIG_LPC17_CAN1
can_interrupt(&g_can1dev);
#endif
#ifdef CONFIG_LPC17_CAN2
can_interrupt(&g_can2dev);
#endif
return OK;
}
/****************************************************************************
* Name: can_bittiming
*
* Description:
* Set the CAN bit timing register (BTR) based on the configured BAUD.
*
* The bit timing logic monitors the serial bus-line and performs sampling
* and adjustment of the sample point by synchronizing on the start-bit edge
* and resynchronizing on the following edges.
*
* Its operation may be explained simply by splitting nominal bit time into
* three segments as follows:
*
* 1. Synchronization segment (SYNC_SEG): a bit change is expected to occur
* within this time segment. It has a fixed length of one time quantum
* (1 x tCAN).
* 2. Bit segment 1 (BS1): defines the location of the sample point. It
* includes the PROP_SEG and PHASE_SEG1 of the CAN standard. Its duration
* is programmable between 1 and 16 time quanta but may be automatically
* lengthened to compensate for positive phase drifts due to differences
* in the frequency of the various nodes of the network.
* 3. Bit segment 2 (BS2): defines the location of the transmit point. It
* represents the PHASE_SEG2 of the CAN standard. Its duration is
* programmable between 1 and 8 time quanta but may also be automatically
* shortened to compensate for negative phase drifts.
*
* Pictorially:
*
* |<----------------- NOMINAL BIT TIME ----------------->|
* |<- SYNC_SEG ->|<------ BS1 ------>|<------ BS2 ------>|
* |<---- Tq ---->|<----- Tbs1 ------>|<----- Tbs2 ------>|
*
* Where
* Tbs1 is the duration of the BS1 segment
* Tbs2 is the duration of the BS2 segment
* Tq is the "Time Quantum"
*
* Relationships:
*
* baud = 1 / bit_time
* bit_time = Tq + Tbs1 + Tbs2
* Tbs1 = Tq * ts1
* Tbs2 = Tq * ts2
* Tq = brp * Tpclk1
*
* Where:
* Tpclk1 is the period of the APB clock (PCLK = CCLK / 4).
*
* Input Parameter:
* priv - A reference to the CAN block status
*
* Returned Value:
* Zero on success; a negated errno on failure
*
****************************************************************************/
static int can_bittiming(struct up_dev_s *priv)
{
uint32_t canbtr;
uint32_t brp;
uint32_t ts1;
uint32_t ts2;
uint32_t sjw;
canllvdbg("CAN%d PCLK1: %d baud: %d\n", priv->port,
CAN_CLOCK_FREQUENCY(priv->divisor), priv->baud);
/* Try to get 14 quanta in one bit_time. That is based on the idea that the ideal
* would be ts1=6 nd ts2=7 and (1 + ts1 + ts2) = 14.
*
* bit_time = Tq*(1 +ts1 + ts2)
* nquanta = bit_time/Tq
* nquanta = (1 +ts1 + ts2)
*
* bit_time = brp * Tpclk1 * (1 + ts1 + ts2)
* nquanta = bit_time / brp / Tpclk1
* = PCLK1 / baud / brp
* brp = PCLK1 / baud / nquanta;
*
* Example:
* PCLK1 = 42,000,000 baud = 1,000,000 nquanta = 14 : brp = 3
* PCLK1 = 42,000,000 baud = 700,000 nquanta = 14 : brp = 4
*/
canbtr = CAN_CLOCK_FREQUENCY(priv->divisor) / priv->baud;
if (canbtr < 14)
{
/* At the smallest brp value (1), there are already fewer bit times
* (CAN_CLOCK / baud) is already smaller than our goal. brp must be one
* and we need make some reasonalble guesses about ts1 and ts2.
*/
brp = 1;
/* In this case, we have to guess a good value for ts1 and ts2 */
ts1 = (canbtr - 1) >> 1;
ts2 = canbtr - ts1 - 1;
if (ts1 == ts2 && ts1 > 1 && ts2 < 16)
{
ts1--;
ts2++;
}
}
/* Otherwise, nquanta is 14, ts1 is 6, ts2 is 7 and we calculate brp to
* achieve 14 quanta in the bit time
*/
else
{
ts1 = 6;
ts2 = 7;
brp = (canbtr + 7) / 14;
DEBUGASSERT(brp >=1 && brp < 1024);
}
sjw = 1;
canllvdbg("TS1: %d TS2: %d BRP: %d SJW= %d\n", ts1, ts2, brp, sjw);
/* Configure bit timing */
canbtr = ((brp - 1) << CAN_BTR_BRP_SHIFT) |
((ts1 - 1) << CAN_BTR_TESG1_SHIFT) |
((ts2 - 1) << CAN_BTR_TESG2_SHIFT) |
((sjw - 1) << CAN_BTR_SJW_SHIFT);
#ifdef CONFIG_CAN_SAM
/* The bus is sampled 3 times (recommended for low to medium speed buses
* to spikes on the bus-line).
*/
canbtr |= CAN_BTR_SAM;
#endif
canllvdbg("Setting CANxBTR= 0x%08x\n", canbtr);
can_putreg(priv, LPC17_CAN_BTR_OFFSET, canbtr); /* Set bit timing */
return OK;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: lpc17_caninitialize
*
* Description:
* Initialize the selected can port
*
* Input Parameter:
* Port number (for hardware that has mutiple can interfaces)
*
* Returned Value:
* Valid can device structure reference on succcess; a NULL on failure
*
****************************************************************************/
FAR struct can_dev_s *lpc17_caninitialize(int port)
{
FAR struct can_dev_s *candev;
irqstate_t flags;
uint32_t regval;
canllvdbg("CAN%d\n", port);
flags = irqsave();
#ifdef CONFIG_LPC17_CAN1
if (port == 1)
{
/* Enable power to the CAN module */
regval = can_getcommon(LPC17_SYSCON_PCONP);
regval |= SYSCON_PCONP_PCCAN1;
can_putcommon(LPC17_SYSCON_PCONP, regval);
/* Enable clocking to the CAN module (not necessary... already done
* in low level clock configuration logic).
*/
regval = can_getcommon(LPC17_SYSCON_PCLKSEL0);
regval &= ~SYSCON_PCLKSEL0_CAN1_MASK;
regval |= (CAN1_CCLK_DIVISOR << SYSCON_PCLKSEL0_CAN1_SHIFT);
can_putcommon(LPC17_SYSCON_PCLKSEL0, regval);
/* Configure CAN GPIO pins */
lpc17_configgpio(GPIO_CAN1_RD);
lpc17_configgpio(GPIO_CAN1_TD);
candev = &g_can1dev;
}
else
#endif
#ifdef CONFIG_LPC17_CAN2
if (port == 2)
{
/* Enable power to the CAN module */
regval = can_getcommon(LPC17_SYSCON_PCONP);
regval |= SYSCON_PCONP_PCCAN2;
can_putcommon(LPC17_SYSCON_PCONP, regval);
/* Enable clocking to the CAN module (not necessary... already done
* in low level clock configuration logic).
*/
regval = can_getcommon(LPC17_SYSCON_PCLKSEL0);
regval &= ~SYSCON_PCLKSEL0_CAN2_MASK;
regval |= (CAN2_CCLK_DIVISOR << SYSCON_PCLKSEL0_CAN2_SHIFT);
can_putcommon(LPC17_SYSCON_PCLKSEL0, regval);
/* Configure CAN GPIO pins */
lpc17_configgpio(GPIO_CAN2_RD);
lpc17_configgpio(GPIO_CAN2_TD);
candev = &g_can2dev;
}
else
#endif
{
candbg("Unsupported port: %d\n", port);
irqrestore(flags);
return NULL;
}
/* Then just perform a CAN reset operation */
can_reset(candev);
irqrestore(flags);
return candev;
}
#endif
