[U-Boot] [PATCH] arm: dts: am33xx: add u-boot, dm-spl to ocp bus

[Felix Brack]

Hi Hannes,

On 01.02.2019 13:59, Hannes Schmelzer wrote:
> 
> 
> On 2/1/19 12:15 PM, Felix Brack wrote:
>> Hi Hannes,
>>
>> On 31.01.2019 21:18, Hannes Schmelzer wrote:
>>> On 1/31/19 4:59 PM, Tom Rini wrote:
>>>> On Thu, Jan 31, 2019 at 04:48:10PM +0100, Hannes Schmelzer wrote:
>>>>
>>>>> On 1/31/19 3:57 PM, Tom Rini wrote:
>>>>>> On Thu, Jan 31, 2019 at 08:03:19AM +0100, Hannes Schmelzer wrote:
>>>>>>
>>>>>>> commit fdce9d35dc36 ("arm: dts: am33xx: Sync dts with Linux 4.20.0")
>>>>>>> did remove the "u-boot,dm-spl" flag from the 'ocp' bus which was
>>>>>>> introduced with
>>>>>>> commit 19aa4ac09db9 ("dts: am33xx: add u-boot, dm-spl to ocp bus")
>>>>>>>
>>>>>>> Due to this the brppt1_spi board is broken because it cannot
>>>>>>> bind/probe the spi-interface during SPL stage.
>>>>>>>
>>>>>>> This commit adds this flag again.
>>>>>>>
>>>>>>> This flag is needed for having access to the devices below this bus,
>>>>>>> most important is uart and boot-device (spi, mmc, ...) in SPL stage.
>>>>>>>
>>>>>>> Signed-off-by: Hannes Schmelzer <hannes.schmelzer at br-automation.com>
>>>>>>>
>>>>>>> ---
>>>>>>>
>>>>>>>    arch/arm/dts/am33xx.dtsi | 1 +
>>>>>>>    1 file changed, 1 insertion(+)
>>>>>>>
>>>>>>> diff --git a/arch/arm/dts/am33xx.dtsi b/arch/arm/dts/am33xx.dtsi
>>>>>>> index d3dd6a1..0a6b177 100644
>>>>>>> --- a/arch/arm/dts/am33xx.dtsi
>>>>>>> +++ b/arch/arm/dts/am33xx.dtsi
>>>>>>> @@ -160,6 +160,7 @@
>>>>>>>         * the whole bus hierarchy.
>>>>>>>         */
>>>>>>>        ocp {
>>>>>>> +        u-boot,dm-spl;
>>>>>>>            compatible = "simple-bus";
>>>>>>>            #address-cells = <1>;
>>>>>>>            #size-cells = <1>;
>>>>>> We need to put this into one of the -u-boot.dtsi files and then
>>>>>> #include
>>>>>> it from the others, so that we don't keep dropping this flag. 
>>>>>> Thanks!
>>>>> Hi Tom,
>>>>> i'm not sure if we can do that this way because the "ocp" bus has no
>>>>> valid
>>>>> label like other elements.
>>>>> So we have at least to adjust the am33xx.dtsi file like this:
>>>>>
>>>>>           ocp : ocp {
>>>>>                   compatible = "simple-bus";
>>>>>                   .....
>>>>>           }
>>>>>
>>>>> what do you suggest ?
>>>> Er, with the example of arch/arm/dts/am335x-pdu001-u-boot.dtsi should't
>>>> we be able to just do that, globally?  Or is that part _not_ working
>>>> and
>>>> relied on the now removed hunk?
>>> Hi Tom,
>>> I'll verify this tomorrow. But the pdu001 looks good to me.
>>> This would be a solution for my boards too if it does the job.
>>> Keep you up to date.
>>>
> Hi Tom, Felix,
> 
> my boards are now up/running again.
> In fact the removed hunk really hurts all boards (which using dm in spl)
> with a few exceptions:
> 
> arch/arm/dts/am4372-generic-u-boot.dtsi:        ocp {
> arch/arm/dts/am437x-idk-evm-u-boot.dtsi:        ocp {
> arch/arm/dts/omap5-u-boot.dtsi: ocp {
> arch/arm/dts/am335x-pdu001-u-boot.dtsi: ocp {
> arch/arm/dts/am437x-gp-evm-u-boot.dtsi: ocp {
> arch/arm/dts/am437x-sk-evm-u-boot.dtsi: ocp {
> 
> Those do the trick within their own files, either with "u-boot,dm-spl;"
> or "u-boot,dm-pre-reloc;".
> 
> The ocp is in fact the root of all important peripheral, so they all
> have this within.
> Some files do also add the necessary "u-boot,dm-spl;" flag to some other
> devices which are needed for bring up SPL.
> 
> I would suggest to have a "am33xx-u-boot.dtsi" which provides the
> ""u-boot,dm-spl;" or "u-boot,dm-pre-reloc;" (not sure which one is the
> formal correct one),
As Tom already stated: dm-pre-reloc is correct here. More information
and hints about when to use dm-pre-reloc, dm-spl and dm-tpl can be found
in doc/driver-model/README.txt.

> flag at least to the most important "ocp" and also to all devices from
> where the am335x can boot. Does anybody think that we may run into SPL
> size trouble,
> with this little bigger dtb blob in spl ?
> 
As dm-pre-reloc already existed in am33xx.dtsi before syncing this file
with Linux 4.20.0 I don't think that size would be an issue.

> So maybe we can finish the discussion during next week and then i will
> provide a patch adding/using some "am33xx-uboot.dtsi" file.
>
Excellent, many thanks!

regards Felix