dm, serial: problem with using ns16550 driver before relocation on mpc83xx

[Heiko Schocher]

Hello Simon,

Am 05.02.2020 um 18:59 schrieb Simon Glass:
> Hi Heiko,
> 
> On Wed, 5 Feb 2020 at 02:04, Heiko Schocher <hs at denx.de> wrote:
>>
>> Hello Bin, Simon,
>>
>> I just porting the mpc83xx based kmcoge5ne board support DTS and got
>> problems using the serial ns16550 driver.
>>
>> I need the serial driver before rolcation, so I enabled
>> "u-boot,dm-pre-reloc;" as usual in the device tree, but board does not
>> boot ...
>>
>> I found the commit:
>>
>> commit 4687919684e0e4390b9fc20d1809ecaa9dc3cb81
>> Author: Bin Meng <bmeng.cn at gmail.com>
>> Date:   Wed Oct 24 06:36:36 2018 -0700
>>
>>       serial: Remove DM_FLAG_PRE_RELOC flag in various drivers
>>
>> which added to the ns16550 serial driver:
>>
>> diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
>> index 04b604fa2c..1e6fc6c668 100644
>> --- a/drivers/serial/ns16550.c
>> +++ b/drivers/serial/ns16550.c
>> @@ -487,7 +487,9 @@ U_BOOT_DRIVER(ns16550_serial) = {
>>           .priv_auto_alloc_size = sizeof(struct NS16550),
>>           .probe = ns16550_serial_probe,
>>           .ops    = &ns16550_serial_ops,
>> +#if !CONFIG_IS_ENABLED(OF_CONTROL)
>>           .flags  = DM_FLAG_PRE_RELOC,
>> +#endif
>>    };
>>    #endif
>>    #endif /* SERIAL_PRESENT */
>>
>> So, as OF_CONTROL is defined for me, the flag "u-boot,dm-pre-reloc" seems
>> not working anymore ...
>>
>> Adding this back:
>>
>> hs at xmglap:u-boot-secu  [20200205-temp] $ git diff
>> diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
>> index 9851663dc5..386ca9cffa 100644
>> --- a/drivers/serial/ns16550.c
>> +++ b/drivers/serial/ns16550.c
>> @@ -528,7 +528,7 @@ U_BOOT_DRIVER(ns16550_serial) = {
>>           .priv_auto_alloc_size = sizeof(struct NS16550),
>>           .probe = ns16550_serial_probe,
>>           .ops    = &ns16550_serial_ops,
>> -#if !CONFIG_IS_ENABLED(OF_CONTROL)
>> +#if CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)
>>           .flags  = DM_FLAG_PRE_RELOC,
>>    #endif
>>    };
>>
>> and board boots fine with the flag "u-boot,dm-pre-reloc" in DTS ...
>>
>> May I do something wrong here? I found in mainline for example
>> the "arch/powerpc/dts/gdsys/gazerbeam-uboot.dtsi" board, which
>> has the exactly same dts settings than I have now.
>>
>> @Dirk: Can you check, if this board boots with current mainline?
>>
>> Shouldn;t be the logic, that in case OF_CONTROL is enabled and if
>> flag "u-boot,dm-pre-reloc" is set in DTS for the device, the device
>> should be bound before relocation, and we do not need to check, if
>> the driver sets DM_FLAG_PRE_RELOC ?
>>
>> But may I miss here something ...
>>
>> Any hints?
> 
> +Tom Rini
> 
> I found I needed this for rpi.
> 
> http://patchwork.ozlabs.org/patch/1202913/
> 
> But I still haven't gone back to figure out why Tom doesn't.

Hmm... I have added the "u-boot,dm-pre-reloc;" to the uart node.

Like it is for the gazerbeam board, see [1]

It works if "DM_FLAG_PRE_RELOC" is set the driver in flags... no
need for a gpio node before relocation like it is inabove patch.

I wonder if we need DM_FLAG_PRE_RELOC at all in a driver and
OF_CONTROL case. Shouldn't it be enough if the DTB node for the
driver contains the "u-boot,dm-pre-reloc;" property?

bye,
Heiko
[1] https://gitlab.denx.de/u-boot/u-boot/blob/master/arch/powerpc/dts/gdsys/gazerbeam-uboot.dtsi#L238
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