Hi Greg, any more comments, thanks.
On 2016/9/27 21:15, Kefeng Wang wrote:
>
>
> On 2016/9/27 18:57, Greg Kroah-Hartman wrote:
>> On Sat, Sep 24, 2016 at 05:14:25PM +0800, Kefeng Wang wrote:
>>> Declare an OF early console for SBSA UART so that the early console device
>>> can be specified via the "stdout-path" property in device-tree.
>>>
>>> Cc: Russell King <li...@armlinux.org.uk>
>>> Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
>>> Signed-off-by: Kefeng Wang <wangkefeng.w...@huawei.com>
>>> ---
>>> drivers/tty/serial/amba-pl011.c | 1 +
>>> 1 file changed, 1 insertion(+)
>>>
>>> diff --git a/drivers/tty/serial/amba-pl011.c
>>> b/drivers/tty/serial/amba-pl011.c
>>> index 7d9b291..3688d3b 100644
>>> --- a/drivers/tty/serial/amba-pl011.c
>>> +++ b/drivers/tty/serial/amba-pl011.c
>>> @@ -2330,6 +2330,7 @@ static int __init pl011_early_console_setup(struct
>>> earlycon_device *device,
>>> return 0;
>>> }
>>> OF_EARLYCON_DECLARE(pl011, "arm,pl011", pl011_early_console_setup);
>>> +OF_EARLYCON_DECLARE(pl011, "arm,sbsa-uart", pl011_early_console_setup);
>>
>> Why do you need another option for the same thing?
>
>
> It is used to support earlycon(without option) for sbsa-uart in bootargs.
>
> chosen {
> stdout-path = "serial0:115200n8";
> bootargs = "earlycon"
> };
>
> uart0: uart@602b0000 {
> compatible = "arm,sbsa-uart";
> reg = <0x0 0x602b0000 0x0 0x1000>;
> ...
> };
>
> We setup a unique struct with compatible name by OF_EARLYCON_DECLARE,
> #define OF_EARLYCON_DECLARE(_name, compat, fn)
> \
> static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \
> __used __section(__earlycon_table) \
> = { .name = __stringify(_name), \
> .compatible = compat, \
> .setup = fn }
>
> if without this patch(see drivers/of/fdt.c),
>
> early_init_dt_scan_chosen_serial()
> - for (match = __earlycon_table; match < __earlycon_table_end; match++)
> -- if (fdt_node_check_compatible(fdt, offset, match->compatible))
> countinue;
> -- of_setup_earlycon(match, offset, options); // will never touch here.
>
> Thanks,
> Kefeng
>
>>
>> confused,
>>
>> greg k-h
>>
>> .
>>
>
>
> .
>
