struct uart_port {
spinlock_t lock; /* 串口端口锁 */
unsigned int iobase; /* IO端口基地址 */
unsigned char __iomem *membase; /* IO内存基地址,经映射(如ioremap)后的IO内存虚拟基地址 */
unsigned int irq; /* 中断号 */
unsigned int uartclk; /* 串口时钟 */
unsigned int fifosize; /* 串口FIFO缓冲大小 */
unsigned char x_char; /* xon/xoff字符 */
unsigned char regshift; /* 寄存器位移 */
unsigned char iotype; /* IO访问方式 */
unsigned char unused1;
#define UPIO_PORT (0) /* IO端口 */
#define UPIO_HUB6 (1)
#define UPIO_MEM (2) /* IO内存 */
#define UPIO_MEM32 (3)
#define UPIO_AU (4) /* Au1x00 type IO */
#define UPIO_TSI (5) /* Tsi108/109 type IO */
#define UPIO_DWAPB (6) /* DesignWare APB UART */
#define UPIO_RM9000 (7) /* RM9000 type IO */
unsigned int read_status_mask; /* 关心的Rx error status */
unsigned int ignore_status_mask;/* 忽略的Rx error status */
struct uart_info *info; /* pointer to parent info */
struct uart_icount icount; /* 计数器 */
struct console *cons; /* console结构体 */
#ifdef CONFIG_SERIAL_CORE_CONSOLE
unsigned long sysrq; /* sysrq timeout */
#endif
upf_t flags;
#define UPF_FOURPORT ((__force upf_t) (1 << 1))
#define UPF_SAK ((__force upf_t) (1 << 2))
#define UPF_SPD_MASK ((__force upf_t) (0x1030))
#define UPF_SPD_HI ((__force upf_t) (0x0010))
#define UPF_SPD_VHI ((__force upf_t) (0x0020))
#define UPF_SPD_CUST ((__force upf_t) (0x0030))
#define UPF_SPD_SHI ((__force upf_t) (0x1000))
#define UPF_SPD_WARP ((__force upf_t) (0x1010))
#define UPF_SKIP_TEST ((__force upf_t) (1 << 6))
#define UPF_AUTO_IRQ ((__force upf_t) (1 << 7))
#define UPF_HARDPPS_CD ((__force upf_t) (1 << 11))
#define UPF_LOW_LATENCY ((__force upf_t) (1 << 13))
#define UPF_BUGGY_UART ((__force upf_t) (1 << 14))
#define UPF_MAGIC_MULTIPLIER ((__force upf_t) (1 << 16))
#define UPF_CONS_FLOW ((__force upf_t) (1 << 23))
#define UPF_SHARE_IRQ ((__force upf_t) (1 << 24))
#define UPF_BOOT_AUTOCONF ((__force upf_t) (1 << 28))
#define UPF_FIXED_PORT ((__force upf_t) (1 << 29))
#define UPF_DEAD ((__force upf_t) (1 << 30))
#define UPF_IOREMAP ((__force upf_t) (1 << 31))
#define UPF_CHANGE_MASK ((__force upf_t) (0x17fff))
#define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
unsigned int mctrl; /* 当前的moden设置 */
unsigned int timeout; /* character-based timeout */
unsigned int type; /* 端口类型 */
const struct uart_ops *ops; /* 串口端口操作函数集 */
unsigned int custom_divisor;
unsigned int line; /* 端口索引 uart_driver.dev_name加上line组成串口的设备节点的名字 */
resource_size_t mapbase; /* IO内存物理基地址，可用于ioremap */
struct device *dev; /* 父设备 */
unsigned char hub6; /* this should be in the 8250 driver */
unsigned char suspended;
unsigned char unused[2];
void *private_data; /* 端口私有数据,一般为platform数据指针 */
};