Add can driver doc
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Aubr.Cool
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说明:
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本驱动完成了can控制器硬件抽象
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一 CAN Driver 注册
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Can driver注册需要填充以下几个数据结构：
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1、struct can_configure
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{
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rt_uint32_t baud_rate;
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rt_uint32_t msgboxsz;
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rt_uint32_t sndboxnumber;
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rt_uint32_t mode :8;
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rt_uint32_t privmode :8;
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rt_uint32_t reserved :16;
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#ifdef RT_CAN_USING_LED
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const struct rt_can_led* rcvled;
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const struct rt_can_led* sndled;
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const struct rt_can_led* errled;
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#endif /*RT_CAN_USING_LED*/
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rt_uint32_t ticks;
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#ifdef RT_CAN_USING_HDR
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rt_uint32_t maxhdr;
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#endif
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};
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struct can_configure 为can驱动的基本配置信息:
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baud_rate :
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enum CANBAUD
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{
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CAN1MBaud=0, // 1 MBit/sec
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CAN800kBaud, // 800 kBit/sec
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CAN500kBaud, // 500 kBit/sec
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CAN250kBaud, // 250 kBit/sec
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CAN125kBaud, // 125 kBit/sec
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CAN100kBaud, // 100 kBit/sec
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CAN50kBaud, // 50 kBit/sec
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CAN20kBaud, // 20 kBit/sec
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CAN10kBaud // 10 kBit/sec
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};
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配置Can的波特率。
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msgboxsz : Can接收邮箱缓冲数量，本驱动在软件层开辟msgboxsz个接收邮箱。
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sndboxnumber : can 发送通道数量，该配置为Can控制器实际的发送通道数量。
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mode ：
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#define RT_CAN_MODE_NORMAL 0 正常模式
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#define RT_CAN_MODE_LISEN 1 只听模式
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#define RT_CAN_MODE_LOOPBACK 2 自发自收模式
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#define RT_CAN_MODE_LOOPBACKANLISEN 3 自发自收只听模式
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配置Can 的工作状态。
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privmode :
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#define RT_CAN_MODE_PRIV 0x01 处于优先级模式，高优先级的消息优先发送。
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#define RT_CAN_MODE_NOPRIV 0x00
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配置Can driver的优先级模式。
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#ifdef RT_CAN_USING_LED
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const struct rt_can_led* rcvled;
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const struct rt_can_led* sndled;
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const struct rt_can_led* errled;
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#endif /*RT_CAN_USING_LED*/
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配置can led信息, 当前can驱动的led使用了 pin驱动，
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开启RT_CAN_USING_LED时要确保当前系统已实现pin驱动。
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rt_uint32_t ticks : 配置Can driver timer周期。
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#ifdef RT_CAN_USING_HDR
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rt_uint32_t maxhdr;
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#endif
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如果使用硬件过滤，则开启RT_CAN_USING_HDR, maxhdr 为Can控制器过滤表的数量。
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2、struct rt_can_ops
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{
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rt_err_t (*configure)(struct rt_can_device *can, struct can_configure *cfg);
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rt_err_t (*control)(struct rt_can_device *can, int cmd, void *arg);
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int (*sendmsg)(struct rt_can_device *can, const void* buf, rt_uint32_t boxno);
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int (*recvmsg)(struct rt_can_device *can,void* buf, rt_uint32_t boxno);
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};
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struct rt_can_ops 为要实现的特定的can控制器操作。
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rt_err_t (*configure)(struct rt_can_device *can, struct can_configure *cfg);
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configure根据配置信息初始化Can控制器工作模式。
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rt_err_t (*control)(struct rt_can_device *can, int cmd, void *arg);
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control 当前接受以下cmd参数：
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#define RT_CAN_CMD_SET_FILTER 0x13
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#define RT_CAN_CMD_SET_BAUD 0x14
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#define RT_CAN_CMD_SET_MODE 0x15
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#define RT_CAN_CMD_SET_PRIV 0x16
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#define RT_CAN_CMD_GET_STATUS 0x17
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#define RT_CAN_CMD_SET_STATUS_IND 0x18
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int (*sendmsg)(struct rt_can_device *can, const void* buf, rt_uint32_t boxno);
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sendmsg向Can控制器发送数，boxno为发送通道号。
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int (*recvmsg)(struct rt_can_device *can,void* buf, rt_uint32_t boxno);
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recvmsg从Can控制器接收数据，boxno为接收通道号。
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struct rt_can_device
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{
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struct rt_device parent;
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const struct rt_can_ops *ops;
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struct can_configure config;
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struct rt_can_status status;
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rt_uint32_t timerinitflag;
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struct rt_timer timer;
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struct rt_can_status_ind_type status_indicate;
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#ifdef RT_CAN_USING_HDR
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struct rt_can_hdr* hdr;
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#endif
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void *can_rx;
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void *can_tx;
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};
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填充完成后，便可调用rt_hw_can_register完成can驱动的注册。
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二、 CAN Driver 的添加：
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要添加一个新的Can驱动，至少要完成以下接口。
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1、struct rt_can_ops
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{
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rt_err_t (*configure)(struct rt_can_device *can, struct can_configure *cfg);
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rt_err_t (*control)(struct rt_can_device *can, int cmd, void *arg);
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int (*sendmsg)(struct rt_can_device *can, const void* buf, rt_uint32_t boxno);
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int (*recvmsg)(struct rt_can_device *can,void* buf, rt_uint32_t boxno);
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};
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2、 rt_err_t (*control)(struct rt_can_device *can, int cmd, void *arg);
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接口的
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#define RT_CAN_CMD_SET_FILTER 0x13
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#define RT_CAN_CMD_SET_BAUD 0x14
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#define RT_CAN_CMD_SET_MODE 0x15
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#define RT_CAN_CMD_SET_PRIV 0x16
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#define RT_CAN_CMD_GET_STATUS 0x17
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#define RT_CAN_CMD_SET_STATUS_IND 0x18
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若干命令。
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3、can口中断，要完接收，发送结束，以及错误中断。
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#define RT_CAN_EVENT_RX_IND 0x01 /* Rx indication */
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#define RT_CAN_EVENT_TX_DONE 0x02 /* Tx complete */
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#define RT_CAN_EVENT_TX_FAIL 0x03 /* Tx complete */
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#define RT_CAN_EVENT_RX_TIMEOUT 0x05 /* Rx timeout */
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#define RT_CAN_EVENT_RXOF_IND 0x06 /* Rx overflow */
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中断产生后，调用rt_hw_can_isr(struct rt_can_device *can, int event)
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进入相应的操作，其中接收发送中断的event，最低8位为上面的事件，16到24位为通信通道号。
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一个作为一个例子，参见bsp/stm32f10x/driver下的bxcan.c 。
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三、CAN Driver的使用：
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一个使用的例子，参数bsp/stm32f10x/applications下的canapp.c
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四、当前Can驱动，没有实现轮模式，采用中断模式，bxcan驱动工作在loopback模式下的时候不能读数据。
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五、当前Can驱动，在stm32f105上测试，暂无问题。
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