Hi:Bin
Thanks for your advice! I realize that I can use the lpuart as earlycon on
kernel . So I will remove this patch on next vesion.
Thanks
Wenbin Song
Sent from my iPhone
> On Jan 19, 2016, at 18:42, Bin Meng <bmeng...@gmail.com> wrote:
>
> Hi Wenbin,
>
>> On Tue, Jan 19, 2016 at 6:21 PM, Wenbin Song <wenbin.s...@nxp.com> wrote:
>> Hi: Bin,
>> Because we use the ns16550 as the early console when booting kernel ,
>> and the earlycon driver on kernel cannot initialize port->uartclk rightly,
>> So if we want to use it, we must initialize ns16550 on uboot, and use the
>> bootargs as follow :
>> "console=ttyS0,115200 root=/dev/ram0 earlycon=uart8250,0x21c0500 "
>
> I understand this. My question was: U-Boot was booted using LPUART as
> its serial console, why do you bother loading a kernel with another
> serial port as the early console?
>
>> int __init early_serial8250_setup(struct earlycon_device *device,
>> const char *options)
>> {
>> if (!(device->port.membase || device->port.iobase))
>> return -ENODEV;
>>
>> if (!device->baud) {
>> struct uart_port *port = &device->port;
>> unsigned int ier;
>>
>> /* assume the device was initialized, only mask interrupts */
>> ier = serial8250_early_in(port, UART_IER);
>> serial8250_early_out(port, UART_IER, ier & UART_IER_UUE);
>> } else
>> init_port(device);
>>
>> device->con->write = early_serial8250_write;
>> return 0;
>> }
>
> [snip]
>
> Regards,
> Bin
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