Re: [PATCH v4 11/11] serial: 8250_omap: Add omap8250 earlycon

From: Jon Hunter
Date: Wed Jan 13 2016 - 05:10:30 EST



On 13/01/16 09:19, Jon Hunter wrote:
>
> On 12/01/16 19:51, Peter Hurley wrote:
>> Wasn't planning on sending this patch just yet, but oh well.
>>
>> On 01/12/2016 11:41 AM, Peter Hurley wrote:
>>> Add DT earlycon for 8250_omap driver. This boot console is included
>>> for kernels built with CONFIG_SERIAL_EARLYCON=y, CONFIG_OF=y,
>>> CONFIG_SERIAL_8250_OMAP=y, and CONFIG_OF_EARLY_FLATTREE=y.
>>>
>>> This boot console is enabled with the command line option "earlycon"
>>> (without "=<name>...") when the DT 'stdout-path' property matches a
>>> compatible uart. For example,
>>>
>>> / {
>>> chosen {
>>> stdout-path = "serial0:115200";
>>> };
>>>
>>> ....
>>>
>>> aliases {
>>> serial0 = &uart0;
>>> };
>>>
>>> ....
>>>
>>> ocp : ocp {
>>> uart0 : serial@44e09000 {
>>> compatible = "ti,omap3-uart";
>>> }
>>> };
>>> };
>>>
>>> Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
>>> ---
>>> drivers/tty/serial/8250/8250_early.c | 20 ++++++++++++++++++++
>>> 1 file changed, 20 insertions(+)
>>>
>>> diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
>>> index e7cdc0c..d1f6310 100644
>>> --- a/drivers/tty/serial/8250/8250_early.c
>>> +++ b/drivers/tty/serial/8250/8250_early.c
>>> @@ -201,3 +201,23 @@ EARLYCON_DECLARE(rt288x, early_rt288x_setup);
>>> OF_EARLYCON_DECLARE(rt288x, "ralink,rt2880-uart", early_rt288x_setup);
>>>
>>> #endif /* CONFIG_SERIAL_8250_RT288X */
>>
>> This patch may not apply because the context is sitting on top of
>> unsubmitted code. Sorry.
>>
>> Regards,
>> Peter Hurley
>>
>>> +
>>> +#ifdef CONFIG_SERIAL_8250_OMAP
>>> +
>>> +static int __init early_omap8250_setup(struct earlycon_device *device,
>>> + const char *options)
>>> +{
>>> + struct uart_port *port = &device->port;
>>> +
>>> + if (!(device->port.membase || device->port.iobase))
>>> + return -ENODEV;
>>> +
>>> + port->regshift = 2;
>>> + device->con->write = early_serial8250_write;
>>> + return 0;
>>> +}
>
> I see you did not mean to send this out, but would the above still be
> necessary with my patch [0]? I am wondering if with my patch you can
> just add the below OF_EARLYCON_DECLARE() for OMAP?

Sorry, I see that you have also already made the changes I have in patch
[0]. However, still curious why you need the above for OMAP?

Jon

[0] http://marc.info/?l=linux-serial&m=145259482325332&w=2