DM_SERIAL is broken for Kirkwood boards

[Stefan Roese]

Hi Tony,

On 1/27/23 07:13, Tony Dinh wrote:
> Hi all,
> 
> On Thu, Jan 26, 2023 at 3:38 PM Tony Dinh <mibodhi at gmail.com> wrote:
>>
>> Hi all,
>>
>> I ran some tests today (Pogo V4 and NSA310S boards) with the latest
>> master branch and saw the same behavior we've seen before. The boards
>> hung, and the serial console was silent after kwboot finished
>> transferring the u-boot image. I'm running with this DTSI patch below
>> (to enable dm-pre-reloc for uart0).
>>
>> If I deselected DM_SERIAL then both boards booted OK with kwboot.
>>
>> diff --git a/arch/arm/dts/kirkwood-nsa310s.dts
>> b/arch/arm/dts/kirkwood-nsa310s.dts
>> index 09ee76c2a2..6c5a991fde 100644
>> --- a/arch/arm/dts/kirkwood-nsa310s.dts
>> +++ b/arch/arm/dts/kirkwood-nsa310s.dts
>> @@ -317,3 +317,8 @@
>>   &pcie0 {
>>          status = "okay";
>>   };
>> +
>> +&uart0 {
>> +        u-boot,dm-pre-reloc;
>> +        status = "okay";
>> +};
>> diff --git a/arch/arm/dts/kirkwood-pogoplug-series-4.dts
>> b/arch/arm/dts/kirkwood-pogoplug-series-4.dts
>> index 5aa4669ae2..ef495d69f5 100644
>> --- a/arch/arm/dts/kirkwood-pogoplug-series-4.dts
>> +++ b/arch/arm/dts/kirkwood-pogoplug-series-4.dts
>> @@ -98,6 +98,7 @@
>>   };
>>
>>   &uart0 {
>> +       u-boot,dm-pre-reloc;
>>          status = "okay";
>>   };
>>
>> @Michael, it would be great if you could try with your Buffalo board,
>> and see if you will experience the same behavior.
> 
> Looks like this commit was the indirect cause of the problem.
> 
> Convert CONFIG_SYS_NS16550_MEM32 et al to Kconfig
> https://github.com/u-boot/u-boot/commit/9591b63531fa5a34698ee7bb3800af6c4ea6ba2f
> 
> -CONFIG_SYS_NS16550=y
> +CONFIG_SYS_NS16550_SERIAL=y
> +CONFIG_SYS_NS16550_REG_SIZE=-4

Thanks for digging into this. Could you perhaps prepare a patch like
this:

diff --git a/arch/arm/mach-kirkwood/Kconfig b/arch/arm/mach-kirkwood/Kconfig
index 45cc9326368c..438f86922310 100644
--- a/arch/arm/mach-kirkwood/Kconfig
+++ b/arch/arm/mach-kirkwood/Kconfig
@@ -15,6 +15,7 @@ config SHEEVA_88SV131
  config KIRKWOOD_COMMON
         bool
         select DM_SERIAL
+       select SYS_NS16550_SERIAL

  config HAS_CUSTOM_SYS_INIT_SP_ADDR
          bool "Use a custom location for the initial stack pointer address"
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index bb5083201b38..7b575295746b 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -773,7 +773,7 @@ config SYS_NS16550_REG_SIZE
         int "ns16550 register width and endianness"
         depends on SYS_NS16550_SERIAL || SPL_SYS_NS16550_SERIAL
         range -4 4
-       default -4 if ARCH_OMAP2PLUS || ARCH_SUNXI
+       default -4 if ARCH_OMAP2PLUS || ARCH_SUNXI || ARCH_KIRKWOOD
         default 1
         help
           Indicates register width and also endianness. If positive, 
big-endian

Does this work for you?

Thanks,
Stefan