mtk android 串口日志重定向,MTK UART串口调试

一、UART初始化

1. kernel-3.18/drivers/misc/mediatek/uart/uart.c

static int __init mtk_uart_init(void)

{

int ret = ;

tx_history.buffer = kzalloc(UART_HISTORY_DATA_SIZE, GFP_KERNEL);

rx_history.buffer = kzalloc(UART_HISTORY_DATA_SIZE, GFP_KERNEL);

tx_history.index = -;

rx_history.index = -;

if (!tx_history.buffer || !rx_history.buffer)

return -ENOMEM;

#ifndef CONFIG_MTK_SERIAL_CONSOLE

mtk_uart_init_ports();

#endif

#if defined(ENABLE_SYSFS)

mtk_uart_sysfs();

#endif

ret = uart_register_driver(&mtk_uart_drv);

if (ret)

return ret;

ret = platform_driver_register(&mtk_uart_dev_drv);

if (ret) {

uart_unregister_driver(&mtk_uart_drv);

return ret;

}

#ifdef CONFIG_PM

mtk_uart_init_ops();

#endif

#ifdef ENABLE_RAW_DATA_DUMP

mtk_uart_init_debug_spinlock();

#endif

spin_lock_init(&mtk_uart_bt_lock);

return ret;

}

第 21 行调用 uart_register_driver 函数注册 mtk_uart_drv。

mtk_uart_drv 结构如下：

static struct uart_driver mtk_uart_drv = {

.owner = THIS_MODULE,

.driver_name = DRV_NAME,

.dev_name = "ttyMT",

.major = UART_MAJOR,

.minor = UART_MINOR,

.nr = UART_NR,

#if defined(CONFIG_MTK_SERIAL_CONSOLE) && !defined(CONFIG_MTK_SERIAL_MODEM_TEST)

.cons = &mtk_uart_console,

#endif

};

static struct console mtk_uart_console = {

.name = "ttyMT",

#if !defined(CONFIG_MTK_SERIAL_MODEM_TEST)

/*don't configure UART4 as console */

.write = mtk_uart_console_write,

.setup = mtk_uart_console_setup,

#endif

.device = uart_console_device,

.flags = CON_PRINTBUFFER,

.index = -,

.data = &mtk_uart_drv,

};

uart_register_driver 函数定义在 kernel-3.18/drivers/tty/serial/serial_core.c 文件中，

/**

* uart_register_driver - register a driver with the uart core layer

* @drv: low level driver structure

*

* Register a uart driver with the core driver. We in turn register

* with the tty layer, and initialise the core driver per-port state.

*

* We have a proc file in /proc/tty/driver which is named after the

* normal driver.

*

* drv->port should be NULL, and the per-port structures should be

* registered using uart_add_one_port after this call has succeeded.

*/

int uart_register_driver(struct uart_driver *drv)

{

struct tty_driver *normal;

int i, retval;

BUG_ON(drv->state);

/*

* Maybe we should be using a slab cache for this, especially if

* we have a large number of ports to handle.

*/

drv->state = kzalloc(sizeof(struct uart_state) * drv->nr, GFP_KERNEL);

if (!drv->state)

goto out;

normal = alloc_tty_driver(drv->nr);

if (!normal)

goto out_kfree;

drv->tty_driver = normal;

normal->driver_name = drv->driver_name;

normal->name = drv->dev_name;

normal->major = drv->major;

normal->minor_start = drv->minor;

normal->type = TTY_DRIVER_TYPE_SERIAL;

normal->subtype = SERIAL_TYPE_NORMAL;

normal->init_termios = tty_std_termios;

normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;

normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;

normal->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;

normal-