Re: [PATCH v0 1/2] aspeed: support uart controller both 0 and 1 base

[Cédric Le Goater]

On 2/5/24 11:46, Cédric Le Goater wrote:
> Hello Jamin,
>
> On 2/5/24 10:14, Jamin Lin wrote:
> > According to the design of ASPEED SOCS, the uart controller
> > is 1 base for ast10x0, ast2600, ast2500 and ast2400.
> >
> > However, the uart controller is 0 base for ast2700.
> > To support uart controller both 0 and 1 base,
> > adds uasrt_bases parameter in AspeedSoCClass
> > and set the default uart controller 1 base
> > for ast10x0, astt2600, ast2500 and ast2400.
>
> The board definition can set 'amc->uart_default' to choose a different
> default serial port for the console, or use the "bmc-console" machine
> option . Isn't it enough ? May be I am misunderstanding the need.
>
> To clarify,
>
> ASPEED_DEV_UART1 is in the first serial port on the boards.
>
> I think we chose to start the indexing at 1 because the Aspeed QEMU
> modeling began first with the UART model (console) and for simplicity,
> we copied the definitions of the device tree from Linux :
>
>      serial0 = &uart1;
>      serial1 = &uart2;
>      serial2 = &uart3;
>      serial3 = &uart4;
>      serial4 = &uart5;
>      serial5 = &vuart;

The uart definitions on the AST2700 are different :
  
  https://github.com/AspeedTech-BMC/linux/blob/aspeed-master-v6.6/arch/arm64/boot/dts/aspeed/aspeed-g7.dtsi

        serial0 = &uart0;
        serial1 = &uart1;
        serial2 = &uart2;
        serial3 = &uart3;
        serial4 = &uart4;
        serial5 = &uart5;
        serial6 = &uart6;
        serial7 = &uart7;
        serial8 = &uart8;
        ...

I think the names in the DT (and consequently in the QEMU models)
follow the IP names in the datasheet.

I don't think we care in QEMU, so I would be inclined to change the
indexing of the device names in QEMU and start at 0, which would
introduce a discrepancy for the AST2400, AST2600, AST2600 SoC.

Let's see what the other maintainers have to say.

Thanks,

C.