linux pl011串口简述

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            *** Non-8250 serial port support ***                                             
        < > ARM AMBA PL010 serial port support                                             
        <*> ARM AMBA PL011 serial port support                                              
        [*]   Support for console on AMBA serial port                                        
       < > MAX3100 support                                                                
        < > MAX3107 support                                                                
        < > Support for timberdale UART                                                    
        < > Altera JTAG UART support                                                       
        < > Altera UART support                                                            
        < > SPI protocol driver for Infineon 6x60 modem (EXPERIMENTAL)                  
        < > Xilinx PS UART support                                                         
        < > Nexell S3C SoC serial port support                                             
        [*]   Serial port 0                                                                
        [ ]     Use DMA                                                                    
        [*]   Serial port 1                                                                
        [ ]     Use DMA                                                                    
        [ ]   Serial port 2                                                                
        [*]   Serial port 3                                                                
        [*]   Serial port 4                                                                
        [ ]   Serial port 5                                                                
        [*] Set this to reduce resume time (PL011) 

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root@NanoPi2:~# ls /proc/tty/driver/
ttyAMA  usbserial
root@NanoPi2:~# cat /proc/tty/driver/ttyAMA 
serinfo:1.0 driver revision:
0: uart:PL011 rev3 mmio:0xC00A1000 irq:7 tx:2846 rx:133 RTS|DTR
1: uart:PL011 rev3 mmio:0xC00A0000 irq:6 tx:0 rx:0 DSR|CD
2: uart:PL011 rev3 mmio:0xC00A3000 irq:9 tx:0 rx:0
3: uart:PL011 rev3 mmio:0xC006D000 irq:10 tx:0 rx:0
root@NanoPi2:~# ls /dev/ttyAMA* -l
crw------- 1 root tty     204, 64 Sep 20 04:21 /dev/ttyAMA0
crw-rw---- 1 root dialout 204, 65 Sep 20 03:28 /dev/ttyAMA1
crw-rw---- 1 root dialout 204, 66 Sep 20 03:28 /dev/ttyAMA2
crw-rw---- 1 root dialout 204, 67 Sep 20 03:28 /dev/ttyAMA3

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static int __init pl011_init(void)
{
	int ret;
	ret = uart_register_driver(&amba_reg);
	if (ret == 0) {
		ret = amba_driver_register(&pl011_driver);
		if (ret)
			uart_unregister_driver(&amba_reg);
	}
	return ret;
}
static void __exit pl011_exit(void)
{
	amba_driver_unregister(&pl011_driver);
	uart_unregister_driver(&amba_reg);
}

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static struct uart_driver amba_reg = {
	.owner			= THIS_MODULE,
	.driver_name		= "ttyAMA",/* /proc/tty/sesial/ttyAMA */
	.dev_name		= "ttyAMA",   /* /dev/ttyAMA */
	.major			= SERIAL_AMBA_MAJOR,  /* /dev/ttyAMAn的节点信息 */
	.minor			= SERIAL_AMBA_MINOR,
	.nr			= UART_NR,
	.cons			= AMBA_CONSOLE,
};
//----------------
static struct amba_id pl011_ids[] = {
	{
		.id	= 0x00041011,
		.mask	= 0x000fffff,
		.data	= &vendor_arm,
	},
	{
		.id	= 0x00380802,
		.mask	= 0x00ffffff,
		.data	= &vendor_st,
	},
	{ 0, 0 },
};
MODULE_DEVICE_TABLE(amba, pl011_ids);
static struct amba_driver pl011_driver = {
	.drv = {
		.name	= "uart-pl011",
	},
	.id_table	= pl011_ids,/*用来匹配设备的,*/
	.probe		= pl011_probe,/*在里面实现了uart_port的注册和uart_ops的赋值*/
	.remove		= pl011_remove,
};

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static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
{
	struct uart_amba_port *uap;
	...
	uap->port.ops = &amba_pl011_pops;
	...
	ret = uart_add_one_port(&amba_reg, &uap->port);
	...
}

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drv->drv.bus = &amba_bustype;//表明将该驱动注册到amba_bus总线上去,由amba_bus中的match方法匹配

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dev->dev.bus = &amba_bustype;//同样将设备注册到amba_bus总线上去，由amba_bus中的match方法匹配

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int amba_device_add(struct amba_device *dev, struct resource *parent)
{
	...
	/* Hard-coded primecell ID instead of plug-n-play */
	if (dev->periphid != 0)/*如果在添加设备时自行加了id就不再读取硬件上的ID了*/
		goto skip_probe;
	...
	ret = amba_get_enable_pclk(dev);
	if (ret == 0) {
		u32 pid, cid;
		/*
		 * Read pid and cid based on size of resource
		 * they are located at end of region 在芯片资源的末区域读取ID信息
		 */
		for (pid = 0, i = 0; i < 4; i++)
			pid |= (readl(tmp + size - 0x20 + 4 * i) & 255) <<
				(i * 8);
		for (cid = 0, i = 0; i < 4; i++)
			cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) <<
				(i * 8);

		amba_put_disable_pclk(dev);

		if (cid == AMBA_CID)
			dev->periphid = pid;
		if (!dev->periphid)
			ret = -ENODEV;
	}
	...
}

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struct bus_type amba_bustype = {
	...
	.match		= amba_match,
	...
};

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sequenceDiagram
amba_driver->>amba_bus:amba_driver_register()
amba_device->>amba_bus:amba_device_register()

amba_device--amba_driver:通过ID
amba_driver-->>amba_device:(dev->>periphid & table->>mask) == table->>id