Re: [Qemu-devel] [PATCH v3 2/2] hw/arm/virt-acpi-build: Add SPCR table

[Peter Maydell]

On 10 June 2015 at 10:52, Andrew Jones <address@hidden> wrote:
> Signed-off-by: Andrew Jones <address@hidden>
> Tested-by: Shannon Zhao <address@hidden>
> ---
>  hw/arm/virt-acpi-build.c | 43 ++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 42 insertions(+), 1 deletion(-)
>
> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> index a9373ccaca6cb..d5a8b9c0178ea 100644
> --- a/hw/arm/virt-acpi-build.c
> +++ b/hw/arm/virt-acpi-build.c
> @@ -84,6 +84,12 @@ static void acpi_dsdt_add_uart(Aml *scope, const 
> MemMapEntry *uart_memmap,
>                 aml_interrupt(AML_CONSUMER, AML_LEVEL, AML_ACTIVE_HIGH,
>                               AML_EXCLUSIVE, uart_irq));
>      aml_append(dev, aml_name_decl("_CRS", crs));
> +
> +    /* The _ADR entry is used to link this device to the UART described
> +     * in the SPCR table, i.e. SPCR.base_address.address == _ADR.
> +     */
> +    aml_append(dev, aml_name_decl("_ADR", aml_int(uart_memmap->base)));
> +
>      aml_append(scope, dev);
>  }
>
> @@ -334,6 +340,38 @@ build_rsdp(GArray *rsdp_table, GArray *linker, unsigned 
> rsdt)
>  }
>
>  static void
> +build_spcr(GArray *table_data, GArray *linker, VirtGuestInfo *guest_info)
> +{
> +    AcpiSerialPortConsoleRedirection *spcr;
> +    const MemMapEntry *uart_memmap = &guest_info->memmap[VIRT_UART];
> +    int irq = guest_info->irqmap[VIRT_UART] + ARM_SPI_BASE;
> +
> +    spcr = acpi_data_push(table_data, sizeof(*spcr));
> +
> +    spcr->interface_type = 0x3;    /* ARM PL011 UART */
> +
> +    spcr->base_address.space_id = AML_SYSTEM_MEMORY;
> +    spcr->base_address.bit_width = 8;
> +    spcr->base_address.bit_offset = 0;
> +    spcr->base_address.access_width = 1;
> +    spcr->base_address.address = cpu_to_le64(uart_memmap->base);
> +
> +    spcr->interrupt_types = (1 << 3); /* Bit[3] ARMH GIC interrupt */
> +    spcr->gsi = cpu_to_le32(irq);  /* Global System Interrupt */

I'm still confused about when fields in these ACPI structs
need to be converted to little-endian, and when they don't.
Is there a rule-of-thumb I can use when I'm looking at patches?

thanks
-- PMM