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SubjectRe: [RFC PATCH 6/7] ARM: dts: stm32: add ETZPC as a system bus for STM32MP15x boards
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On 12/22/22 16:21, Krzysztof Kozlowski wrote:
> On 22/12/2022 15:42, Gatien CHEVALLIER wrote:
>> Hello,
>>
>>
>> On 12/22/22 11:30, Krzysztof Kozlowski wrote:
>>> On 21/12/2022 18:30, Gatien Chevallier wrote:
>>>> The STM32 System Bus is an internal bus on which devices are connected.
>>>> ETZPC is a peripheral overseeing the firewall bus that configures
>>>> and control access to the peripherals connected on it.
>>>>
>>>> For more information on which peripheral is securable, please read
>>>> the STM32MP15 reference manual.
>>>>
>>>> Signed-off-by: Gatien Chevallier <gatien.chevallier@foss.st.com>
>>>> ---
>>>> arch/arm/boot/dts/stm32mp151.dtsi | 2737 +++++++++++++++--------------
>>>> 1 file changed, 1406 insertions(+), 1331 deletions(-)
>>>>
>>>> - lptimer1: timer@40009000 {
>>>> + etzpc: etzpc@5c007000 {
>>>
>>> Node names should be generic.
>>> https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#generic-names-recommendation
>>
>> Will change to etzpc: bus@5c007000 in V3
>>
>>>
>>>> + compatible = "st,stm32mp15-sys-bus";
>>>> + reg = <0x5c007000 0x400>;
>>>> #address-cells = <1>;
>>>> - #size-cells = <0>;
>>>> - compatible = "st,stm32-lptimer";
>>>> - reg = <0x40009000 0x400>;
>>>> - interrupts-extended = <&exti 47 IRQ_TYPE_LEVEL_HIGH>;
>>>> - clocks = <&rcc LPTIM1_K>;
>>>> - clock-names = "mux";
>>>> - wakeup-source;
>>>> - status = "disabled";
>>>
>>> Why entire bus is disabled? What resources do you miss?
>>
>> Here, I did not want to modify the status of the nodes in the device
>
> By making it disabled you actually modify the status of any enabled
> node. By making it enabled you do not cause any change.
>
>> tree. Nodes that are default enabled in the SoC device tree stay enabled
>> and vice-versa.
>
> No, because parent is disabled.
>
>> IMO think this patch should not include these kind of
>> changes in its scope. I describe the bus and the peripherals connected
>> to it, nothing more :)
>
> I am not proposing to change existing nodes. I am asking why new node is
> being disabled (because it is a new node, isn't it?).

I'm sorry but the ETZPC node is not disabled. The patch is quite hard to
read as I'm moving all securable/MCU isolation capable peripheral nodes
under ETZPC.

>>>> - #size-cells = <0>;
>>>> - compatible = "st,stm32-lptimer";
>>>> - reg = <0x40009000 0x400>;
>>>> - interrupts-extended = <&exti 47 IRQ_TYPE_LEVEL_HIGH>;
>>>> - clocks = <&rcc LPTIM1_K>;
>>>> - clock-names = "mux";
>>>> - wakeup-source;
>>>> - status = "disabled";

are part of lptimer1 node, which is moved under ETZPC. ETZPC node is
default enabled.

Result after patch is:

etzpc: etzpc@5c007000 {
compatible = "st,stm32mp15-sys-bus";
reg = <0x5c007000 0x400>;
#address-cells = <1>;
#size-cells = <1>;
feature-domain-controller;
#feature-domain-cells = <2>;
ranges;

timers2: timer@40000000 {
(...)

Or do I misunderstand you comment?

>
> Best regards,
> Krzysztof
>

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