Bug: qemu_arm64: Cannot access the second flash bank

[Matthias Brugger]

Hi Robin,

On 09/01/2020 16:21, Robin Randhawa wrote:
> On Thu, 2020-01-09 at 15:57 +0100, Matthias Brugger wrote:
> 
> [...]
> 
>> The property expects size-cells to be two, but U-Boot will use one
>> cell if no
>> size-cells are defined in the device node (which is not the case) and
>> therefor
>> will see
>>
>> Bank1: Flashbase 0x0 0x0         Flashsize 0x4000000
>> Bank2: Flashbase 0x4000000 0x0   Flashsize 0x4000000
> 
> My knowledge of DT is superficial. However, looking at the following
> lines from the spec:
> 
> - A |spec|-compliant boot program shall supply #address-cells and
> #size-cells on all nodes that have children.
> 
> - If missing, a client program should assume a default value of 2 for
> #address-cells, and a value of 1 for #size-cells.
> 
> .. and contrasting with the root node and device node in question from
> the DTS for this platform:
> 
> / {
> 	interrupt-parent = <0x8001>;
> 	#size-cells = <0x2>;
> 	#address-cells = <0x2>;
> 	compatible = "linux,dummy-virt";
> .
> .
> 
> 	flash at 0 {
> 		bank-width = <0x4>;
> 		reg = <0x0 0x0 0x0 0x4000000 0x0 0x4000000 0x0 0x4000000>;
> 		compatible = "cfi-flash";
> 	};
> 
> .. it seems to me that while the flash node is missing #size-cells,
> given that #size-cells _is_ defined in the parent node ("the node that
> has children") then that value (0x2) is the one u-boot should have used
> but didn't.
> 
> Maybe the u-boot DT interpreting logic needs to check if the parent
> node also does not specify #size-cells before making the assumption
> that the value 1 is to be used ?
> 

Sorry for taking so long. Yes you are correct, I found the issue in U-Boot and
I'm working on a patch. Please stay tuned.

Regards,
Matthias