On Fri, 20 Sep 2019 at 15:15, Cédric Le Goater <c...@kaod.org> wrote:
>
> On 20/09/2019 06:10, Andrew Jeffery wrote:
> >
> >
> > On Thu, 19 Sep 2019, at 15:19, Cédric Le Goater wrote:
> >> From: Joel Stanley <j...@jms.id.au>
> >>
> >> The SCU controller on the AST2600 SoC has extra registers. Increase
> >> the number of regs of the model and introduce a new field in the class
> >> to customize the MemoryRegion operations depending on the SoC model.
> >>
> >> + switch (reg) {
> >> + case AST2600_PROT_KEY:
> >> + s->regs[reg] = (data == ASPEED_SCU_PROT_KEY) ? 1 : 0;
> >> + return;
> >> + case AST2600_HW_STRAP1:
> >> + case AST2600_HW_STRAP2:
> >> + if (s->regs[reg + 2]) {
> >> + return;
> >> + }
> >> + /* fall through */
> >> + case AST2600_SYS_RST_CTRL:
> >> + case AST2600_SYS_RST_CTRL2:
> >> + /* W1S (Write 1 to set) registers */
> >> + s->regs[reg] |= data;
> >> + return;
> >> + case AST2600_SYS_RST_CTRL_CLR:
> >> + case AST2600_SYS_RST_CTRL2_CLR:
> >> + case AST2600_HW_STRAP1_CLR:
> >> + case AST2600_HW_STRAP2_CLR:
> >> + /* W1C (Write 1 to clear) registers */
> >> + s->regs[reg] &= ~data;
> >
> > This clear should respect the protection register for each strap case.
>
> Joel,
>
> You are the expert ! :)
Someone could implement this if they wanted to. In the future it might
be useful to create a detailed model for the OTP and secure boot
behavior, and that can affect the strapping.
However it is not critical for running guests under qemu. I think we
should defer it until there is some guest code that needs the detailed
behavior.
Cheers,
Joel
