Re: [SeaBIOS] [Qemu-devel] [PATCH v3 for-2.3 10/24] hw/apci: add _PRT method for extra PCI root busses

[Michael S. Tsirkin]

On Thu, Mar 05, 2015 at 04:55:08PM +0200, Marcel Apfelbaum wrote:
> Signed-off-by: Marcel Apfelbaum
>
> hw/i386/acpi-build.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 78 insertions(+)
>
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index e5709e8..f0401d2 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -664,6 +664,83 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
>      aml_append(parent_scope, method);
>  }
>
> +static Aml *build_prt(void)
> +{
> Aml *method, *pkg, *if_ctx, *while_ctx;
> method = aml_method("_PRT", 0);
> aml_append(method, aml_store(aml_package(128), aml_local(0)));
> aml_append(method, aml_store(aml_int(0), aml_local(1)));
> while_ctx = aml_while(aml_lless(aml_local(1), aml_int(128)));
> {
>    aml_append(while_ctx,
>        aml_store(aml_shiftright(aml_local(1), aml_int(2)), aml_local(2)));
>    aml_append(while_ctx,
>        aml_store(aml_and(aml_add(aml_local(1), aml_local(2)), aml_int(3)),
>                  aml_local(3)));
>    if_ctx = aml_if(aml_equal(aml_local(3), aml_int(0)));
>    {
>        pkg = aml_package(4);
>        aml_append(pkg, aml_int(0));
>        aml_append(pkg, aml_int(0));
>        aml_append(pkg, aml_name("LNKD"));
>        aml_append(pkg, aml_int(0));
>        aml_append(if_ctx, aml_store(pkg, aml_local(4)));
>    }
>    aml_append(while_ctx, if_ctx);
>    if_ctx = aml_if(aml_equal(aml_local(3), aml_int(1)));
>    {
>        pkg = aml_package(4);
>        aml_append(pkg, aml_int(0));
>        aml_append(pkg, aml_int(0));
>        aml_append(pkg, aml_name("LNKA"));
>        aml_append(pkg, aml_int(0));
>        aml_append(if_ctx, aml_store(pkg, aml_local(4)));
>    }
>    aml_append(while_ctx, if_ctx);
>    if_ctx = aml_if(aml_equal(aml_local(3), aml_int(2)));
>    {
>        pkg = aml_package(4);
>        aml_append(pkg, aml_int(0));
>        aml_append(pkg, aml_int(0));
>        aml_append(pkg, aml_name("LNKB"));
>        aml_append(pkg, aml_int(0));
>        aml_append(if_ctx, aml_store(pkg, aml_local(4)));
>    }
>    aml_append(while_ctx, if_ctx);
>    if_ctx = aml_if(aml_equal(aml_local(3), aml_int(3)));
>    {
>        pkg = aml_package(4);
>        aml_append(pkg, aml_int(0));
>        aml_append(pkg, aml_int(0));
>        aml_append(pkg, aml_name("LNKC"));
>        aml_append(pkg, aml_int(0));
>        aml_append(if_ctx, aml_store(pkg, aml_local(4)));
>    }
>    aml_append(while_ctx, if_ctx);
>    aml_append(while_ctx,
>        aml_store(aml_or(aml_shiftleft(aml_local(2), aml_int(16)),
>                         aml_int(0xFFFF)),
>                  aml_index(aml_local(4), aml_int(0))));
>    aml_append(while_ctx,
>        aml_store(aml_and(aml_local(1), aml_int(3)),
>                  aml_index(aml_local(4), aml_int(1))));
>    aml_append(while_ctx,
>        aml_store(aml_local(4), aml_index(aml_local(0), aml_local(1))));
>    aml_append(while_ctx, aml_increment(aml_local(1)));
> }
> aml_append(method, while_ctx);
> aml_append(method, aml_return(aml_local(0)));
> return method;
>
> +}

Pls improve readability of this code using comments, sub-functions and
local variables.
> static void
>  build_ssdt(GArray *table_data, GArray *linker,
>             AcpiCpuInfo *cpu, AcpiPmInfo *pm, AcpiMiscInfo *misc,
> @@ -708,6 +785,7 @@ build_ssdt(GArray *table_data, GArray *linker,
>              aml_append(dev, aml_name_decl("_HID", aml_string("PNP0A03")));
>              aml_append(dev,
>                  aml_name_decl("_BBN", aml_int((uint8_t)bus_info->bus)));
>        aml_append(dev, build_prt());
>        aml_append(scope, dev);
>        aml_append(ssdt, scope);
>    }