pios_can.c

Go to the documentation of this file.

/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, see <http://www.gnu.org/licenses/>
 */


#include "pios.h"

#if defined(PIOS_INCLUDE_CAN)

#include "pios_can_priv.h"

/* Provide a COM driver */
static void PIOS_CAN_RegisterRxCallback(uintptr_t can_id, pios_com_callback rx_in_cb, uintptr_t context);
static void PIOS_CAN_RegisterTxCallback(uintptr_t can_id, pios_com_callback tx_out_cb, uintptr_t context);
static void PIOS_CAN_TxStart(uintptr_t can_id, uint16_t tx_bytes_avail);
static void PIOS_CAN_RxStart(uintptr_t can_id, uint16_t rx_bytes_avail);

const struct pios_com_driver pios_can_com_driver = {
        .tx_start   = PIOS_CAN_TxStart,
        .rx_start   = PIOS_CAN_RxStart,
        .bind_tx_cb = PIOS_CAN_RegisterTxCallback,
        .bind_rx_cb = PIOS_CAN_RegisterRxCallback,
};

enum pios_can_dev_magic {
        PIOS_CAN_DEV_MAGIC = 0x41fa834A,
};

struct pios_can_dev {
        enum pios_can_dev_magic     magic;
        const struct pios_can_cfg  *cfg;
        pios_com_callback rx_in_cb;
        uintptr_t rx_in_context;
        pios_com_callback tx_out_cb;
        uintptr_t tx_out_context;
};

// Local constants
#define CAN_COM_ID      0x11
#define MAX_SEND_LEN    8

void USB_HP_CAN1_TX_IRQHandler(void);

static bool PIOS_CAN_validate(struct pios_can_dev *can_dev)
{
        return (can_dev->magic == PIOS_CAN_DEV_MAGIC);
}

static struct pios_can_dev *PIOS_CAN_alloc(void)
{
        struct pios_can_dev *can_dev;

        can_dev = (struct pios_can_dev *)PIOS_malloc(sizeof(*can_dev));
        if (!can_dev) return(NULL);

        memset(can_dev, 0, sizeof(*can_dev));
        can_dev->magic = PIOS_CAN_DEV_MAGIC;

        return(can_dev);
}

static struct pios_can_dev *can_dev;

int32_t PIOS_CAN_Init(uintptr_t *can_id, const struct pios_can_cfg *cfg)
{
        PIOS_DEBUG_Assert(can_id);
        PIOS_DEBUG_Assert(cfg);

        can_dev = (struct pios_can_dev *) PIOS_CAN_alloc();
        if (!can_dev) goto out_fail;

        /* Bind the configuration to the device instance */
        can_dev->cfg = cfg;

        /* Configure the CAN device */
        RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1, ENABLE);

        /* Map pins to CAN function */
        if (can_dev->cfg->remap) {
                if (can_dev->cfg->rx.gpio != 0)
                        GPIO_PinAFConfig(can_dev->cfg->rx.gpio,
                                can_dev->cfg->rx.pin_source,
                                can_dev->cfg->remap);
                if (can_dev->cfg->tx.gpio != 0)
                        GPIO_PinAFConfig(can_dev->cfg->tx.gpio,
                                can_dev->cfg->tx.pin_source,
                                can_dev->cfg->remap);
        }

        /* Initialize the CAN Rx and Tx pins */
        if (can_dev->cfg->rx.gpio != 0)
                GPIO_Init(can_dev->cfg->rx.gpio, (GPIO_InitTypeDef *)&can_dev->cfg->rx.init);
        if (can_dev->cfg->tx.gpio != 0)
                GPIO_Init(can_dev->cfg->tx.gpio, (GPIO_InitTypeDef *)&can_dev->cfg->tx.init);

        *can_id = (uintptr_t)can_dev;

        CAN_DeInit(can_dev->cfg->regs);
        CAN_Init(can_dev->cfg->regs, (CAN_InitTypeDef *)&can_dev->cfg->init);

        /* CAN filter init */
        CAN_FilterInitTypeDef CAN_FilterInitStructure;
        CAN_FilterInitStructure.CAN_FilterNumber = 0;
        CAN_FilterInitStructure.CAN_FilterMode = CAN_FilterMode_IdMask;
        CAN_FilterInitStructure.CAN_FilterScale = CAN_FilterScale_32bit;
        CAN_FilterInitStructure.CAN_FilterIdHigh = 0x0000;
        CAN_FilterInitStructure.CAN_FilterIdLow = 0x0000;
        CAN_FilterInitStructure.CAN_FilterMaskIdHigh = 0x0000;
        CAN_FilterInitStructure.CAN_FilterMaskIdLow = 0x0000;  
        CAN_FilterInitStructure.CAN_FilterFIFOAssignment = 1;

        CAN_FilterInitStructure.CAN_FilterActivation = ENABLE;
        CAN_FilterInit(&CAN_FilterInitStructure);

        // Enable the receiver IRQ
        NVIC_Init((NVIC_InitTypeDef*) &can_dev->cfg->rx_irq.init);
        NVIC_Init((NVIC_InitTypeDef*) &can_dev->cfg->tx_irq.init);

        return(0);

out_fail:
        return(-1);
}

static void PIOS_CAN_RxStart(uintptr_t can_id, uint16_t rx_bytes_avail)
{
        struct pios_can_dev *can_dev = (struct pios_can_dev *)can_id;
        
        bool valid = PIOS_CAN_validate(can_dev);
        PIOS_Assert(valid);
        
        CAN_ITConfig(can_dev->cfg->regs, CAN_IT_FMP1, ENABLE);
}

static void PIOS_CAN_TxStart(uintptr_t can_id, uint16_t tx_bytes_avail)
{
        struct pios_can_dev *can_dev = (struct pios_can_dev *)can_id;
        
        bool valid = PIOS_CAN_validate(can_dev);
        PIOS_Assert(valid);

        CAN_ITConfig(can_dev->cfg->regs, CAN_IT_TME, ENABLE);
        
        USB_HP_CAN1_TX_IRQHandler();
}

static void PIOS_CAN_RegisterRxCallback(uintptr_t can_id, pios_com_callback rx_in_cb, uintptr_t context)
{
        struct pios_can_dev *can_dev = (struct pios_can_dev *)can_id;

        bool valid = PIOS_CAN_validate(can_dev);
        PIOS_Assert(valid);
        
        /* 
         * Order is important in these assignments since ISR uses _cb
         * field to determine if it's ok to dereference _cb and _context
         */
        can_dev->rx_in_context = context;
        can_dev->rx_in_cb = rx_in_cb;
}

static void PIOS_CAN_RegisterTxCallback(uintptr_t can_id, pios_com_callback tx_out_cb, uintptr_t context)
{
        struct pios_can_dev *can_dev = (struct pios_can_dev *)can_id;

        bool valid = PIOS_CAN_validate(can_dev);
        PIOS_Assert(valid);
        
        /* 
         * Order is important in these assignments since ISR uses _cb
         * field to determine if it's ok to dereference _cb and _context
         */
        can_dev->tx_out_context = context;
        can_dev->tx_out_cb = tx_out_cb;
}

static uint32_t pios_can_message_stdid[PIOS_CAN_LAST] = {
        [PIOS_CAN_GIMBAL] = 0x130,
};

static struct pios_queue *pios_can_queues[PIOS_CAN_LAST];

static bool process_received_message(CanRxMsg message)
{
        // Look for a known message that matches this CAN StdId
        uint32_t msg_id;
        for (msg_id = 0; msg_id < PIOS_CAN_LAST && pios_can_message_stdid[msg_id] != message.StdId; msg_id++);

        // If StdId is not one of the known messages, bail out
        if (msg_id == PIOS_CAN_LAST)
                return false;

        // Get the queue for this message and send the data
        struct pios_queue *queue = pios_can_queues[msg_id];
        if (queue == NULL)
                return false;

        bool woken = false;
        PIOS_Queue_Send_FromISR(queue, message.Data, &woken);

        return woken;
}

struct pios_queue * PIOS_CAN_RegisterMessageQueue(uintptr_t id, enum pios_can_messages msg_id)
{
        // Fetch the size of this message type or error if unknown
        uint32_t bytes;
        switch(msg_id) {
        case PIOS_CAN_GIMBAL:
                bytes = sizeof(struct pios_can_gimbal_message);
                break;
        default:
                return NULL;
        }

        // Return existing queue if created
        if (pios_can_queues[msg_id] != NULL)
                return pios_can_queues[msg_id];

        // Create a queue that can manage the data message size
        struct pios_queue *queue;
        queue = PIOS_Queue_Create(2, bytes);
        if (queue == NULL)
                return NULL;

        // Store the queue handle for the driver
        pios_can_queues[msg_id] = queue;

        return queue;
}

// Map the specific IRQ handlers to the device handle

static void PIOS_CAN_RxGeneric(void);
static void PIOS_CAN_TxGeneric(void);

void CAN1_RX1_IRQHandler(void)
{
        PIOS_IRQ_Prologue();
        PIOS_CAN_RxGeneric();
        PIOS_IRQ_Epilogue();
}

void USB_HP_CAN1_TX_IRQHandler(void)
{
        PIOS_IRQ_Prologue();
        PIOS_CAN_TxGeneric();
        PIOS_IRQ_Epilogue();
}

static void PIOS_CAN_RxGeneric(void)
{
        CAN_ClearITPendingBit(can_dev->cfg->regs, CAN_IT_FMP1);

        bool valid = PIOS_CAN_validate(can_dev);
        PIOS_Assert(valid);

        CanRxMsg RxMessage;
        CAN_Receive(CAN1, CAN_FIFO1, &RxMessage);

        bool rx_need_yield = false;
        if (RxMessage.StdId == CAN_COM_ID) {
                if (can_dev->rx_in_cb) {
                        (void) (can_dev->rx_in_cb)(can_dev->rx_in_context, RxMessage.Data, RxMessage.DLC, NULL, &rx_need_yield);
                }
        } else {
                rx_need_yield = process_received_message(RxMessage);
        }
}

static void PIOS_CAN_TxGeneric(void)
{
        CAN_ClearITPendingBit(can_dev->cfg->regs, CAN_IT_TME);

        bool valid = PIOS_CAN_validate(can_dev);
        PIOS_Assert(valid);

        bool tx_need_yield = false;
        
        if (can_dev->tx_out_cb) {

                // Prepare CAN message structure
                CanTxMsg msg;
                msg.StdId = CAN_COM_ID;
                msg.ExtId = 0;
                msg.IDE = CAN_ID_STD;
                msg.RTR = CAN_RTR_DATA;                 
                msg.DLC = (can_dev->tx_out_cb)(can_dev->tx_out_context, msg.Data, MAX_SEND_LEN, NULL, &tx_need_yield);

                // Send message and get mailbox number
                if (msg.DLC > 0) {
                        CAN_Transmit(can_dev->cfg->regs, &msg);
                } else {
                        CAN_ITConfig(can_dev->cfg->regs, CAN_IT_TME, DISABLE);
                }

                // TODO: deal with failure to send and keep the message to retransmit
        }
}


int32_t PIOS_CAN_TxData(uintptr_t id, enum pios_can_messages msg_id, uint8_t *data)
{
        // Fetch the size of this message type or error if unknown
        uint32_t bytes;
        switch(msg_id) {
        case PIOS_CAN_GIMBAL:
                bytes = sizeof(struct pios_can_gimbal_message);
                break;
        default:
                return -1;
        }

        // Look up the CAN BUS Standard ID for this message type
        uint32_t std_id = pios_can_message_stdid[msg_id];

        // Format and send the message
        CanTxMsg msg;
        msg.StdId = std_id & 0x7FF;
        msg.ExtId = 0;
        msg.IDE = CAN_ID_STD;
        msg.RTR = CAN_RTR_DATA;                 
        msg.DLC = (bytes > 8) ? 8 : bytes;
        memcpy(msg.Data, data, msg.DLC);
        CAN_Transmit(can_dev->cfg->regs, &msg);

        return msg.DLC;
}


#endif /* PIOS_INCLUDE_CAN */