在serial.h中

struct rt_serial_device
{struct rt_device parent;const struct rt_uart_ops *ops;struct serial_configure config;void *serial_rx;void *serial_tx;struct rt_spinlock spinlock;struct rt_device_notify rx_notify;
}
typedef struct rt_serial_device rt_serial_t;

struct rt_uart_ops
{rt_err_t (*configure)(struct rt_serial_device *serial, struct serial_configure *cfg);rt_err_t (*control)(struct rt_serial_device *serial, int cmd, void *arg);int (*putc)(struct rt_serial_device *serial, char c);int (*getc)(struct rt_serial_device *serial);rt_ssize_t (*dma_transmit)(struct rt_serial_device *serial, rt_uint8_t *buf, rt_size_t size, int direction);
};

struct serial_configure
{rt_uint32_t baud_rate;rt_uint32_t data_bits               :4;rt_uint32_t stop_bits               :2;rt_uint32_t parity                  :2;rt_uint32_t bit_order               :1;rt_uint32_t invert                  :1;rt_uint32_t bufsz                   :16;rt_uint32_t flowcontrol             :1;rt_uint32_t reserved                :5;
};

在drv_usart.h中

struct stm32_uart
{UART_HandleTypeDef handle;struct stm32_uart_config *config;rt_uint32_t DR_mask;rt_uint16_t uart_dma_flag;struct rt_serial_device serial;
};

struct stm32_uart_config
{const char *name;USART_TypeDef *Instance;IRQn_Type irq_type;struct dma_config *dma_rx;struct dma_config *dma_tx;
}

在drv_usart.c中要实现串口驱动框架层定义的接口

static const struct rt_uart_ops stm32_uart_ops =
{.configure = stm32_configure,.control = stm32_control,.putc = stm32_putc,.getc = stm32_getc,.dma_transmit = stm32_dma_transmit
};

然后在初始化函数里去注册设备驱动程序

int rt_hw_usart_init(void)
{struct serial_configure config = RT_SERIAL_CONFIG_DEFAULT;rt_err_t result = 0;stm32_uart_get_dma_config();for(rt_size_t i=0; i<sizeof(uart_obj)/sizeof(struct stm32_uart); i++){/* init UART object */uart_obj[i].config = &uart_config[i];uart_obj[i].serial.ops    = &stm32_uart_ops;uart_obj[i].serial.config = config;/* register UART device */result = rt_hw_serial_register(&uart_obj[i].serialm uart_obj[i].config->name,  RT_DEVICE_FLAG_RDWR| RT_DEVICE_FLAG_INT_RX| RT_DEVICE_FLAG_INT_TX| uart_obj[i].uart_dma_flag, NULL);RT_ASSERT(result == RT_EOK);}return result;
}

static struct stm32_uart uart_objt[sizeof(uart_config)/sizeof(uart_config[0])] = {0};

static struct stm32_uart_config uart_config[] =
{
#ifdef BSP_USING_UART1UART1_CONFIG,
#endif
#ifdef BSP_USING_UART2UART2_CONFIG,
#endif
#ifdef BSP_USING_UART3UART3_CONFIG,
#endif
#ifdef BSP_USING_UART4UART4_CONFIG,
#endif
#ifdef BSP_USING_UART5UART5_CONFIG,
#endif
#ifdef BSP_USING_UART6UART6_CONFIG,
#endif
#ifdef BSP_USING_UART7UART7_CONFIG,
#endif
#ifdef BSP_USING_UART8UART8_CONFIG,
#endif
#ifdef BSP_USING_LPUART1LPUART1_CONFIG,
#endif
};

#ifndef LPUART1_CONFIG
#define LPUART1_CONFIG                                              \{                                                               \.name = "lpuart1",                                          \.Instance = LPUART1,                                        \.irq_type = LPUART1_IRQn,                                   \}
#endif /* LPUART1_CONFIG */

在serial.c中

rt_err_t rt_hw_serial_register(struct rt_serial_device *serial,const char              *name,rt_uint32_t              flag,void                    *data)
{rt_err_t ret;struct rt_device *device;RT_ASSERT(serial != RT_NULL);rt_spin_lock_init(&(serial->spinlock));device = &(serial->parent);device->type        = RT_Device_Class_Char;device->rx_indicate = RT_NULL;device->tx_complete = RT_NULL;#ifdef RT_USING_DEVICE_OPSdevice->ops         = &serial_ops;
#elsedevice->init        = rt_serial_init;device->open        = rt_serial_open;device->close       = rt_serial_close;device->read        = rt_serial_read;device->write       = rt_serial_write;device->control     = rt_serial_control;
#endifdevice->user_data   = data;/* register a character device */ret = rt_device_register(device, name, flag);#ifdef RT_USING_POSIX_STDIO/* set fops */device->fops        = &_serial_fops;
#endifreturn ret;
}