Re: [PATCH edk2-platforms 3/3] Platform/ARM/JunoPkg: Reserve the ECAM area in ACPI with RES0 device

["Sami Mujawar" <sami.mujawar@arm.com>]

Hi Rebecca,

Thank you for this patch. This change looks good to me.

I have a minor suggestion marked inline as [SAMI].

With that upated,

Tested-by: Sami Mujawar <sami.mujawar@arm.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>

Regards,

Sami Mujawar
On 05/03/2022 04:19 AM, Rebecca Cran wrote:
> Add a RES0 device to the SSDT to reserve the PCI ECAM area.
>
> This fixes the warning that Linux prints:
>
> acpi PNP0A08:00: [Firmware Bug]: ECAM area [mem 0x40000000-0x4fffffff]
> not reserved in ACPI namespace
[SAMI] I noticed that the "Firmware Bug" message is no longer seen, but
instead the following message is now printed
"system 00:00: [mem 0x40000000-0x4fffffff window] could not be reserved"

It appears this is a harmless message and the relevant discussion can be
seen at: https://lore.kernel.org/all/20210603141641.GA17284@lpieralisi/#t

I think it may be better to update the commit message to reference this
discussion and clarify that this is an expected behavior.
[/SAMI]

> Signed-off-by: Rebecca Cran <rebecca@bsdio.com>
> ---
>   Platform/ARM/JunoPkg/AcpiTables/AcpiTables.inf      |  4 ++++
>   Platform/ARM/JunoPkg/AcpiTables/AcpiSsdtRootPci.asl | 13 +++++++++++++
>   2 files changed, 17 insertions(+)
>
> diff --git a/Platform/ARM/JunoPkg/AcpiTables/AcpiTables.inf b/Platform/ARM/JunoPkg/AcpiTables/AcpiTables.inf
> index f140febc4ad4..9a76475765f0 100644
> --- a/Platform/ARM/JunoPkg/AcpiTables/AcpiTables.inf
> +++ b/Platform/ARM/JunoPkg/AcpiTables/AcpiTables.inf
> @@ -45,6 +45,10 @@ [FixedPcd]
>     gArmTokenSpaceGuid.PcdGenericWatchdogControlBase
>     gArmTokenSpaceGuid.PcdGenericWatchdogRefreshBase
>
> +  gEfiMdePkgTokenSpaceGuid.PcdPciExpressBaseAddress
> +  gArmJunoTokenSpaceGuid.PcdPciConfigurationSpaceSize
> +  gArmJunoTokenSpaceGuid.PcdPciConfigurationSpaceLimit
> +
>     #
>     # PL011 UART Settings for Serial Port Console Redirection
>     #
> diff --git a/Platform/ARM/JunoPkg/AcpiTables/AcpiSsdtRootPci.asl b/Platform/ARM/JunoPkg/AcpiTables/AcpiSsdtRootPci.asl
> index 317b621e013e..e60fc42a3340 100644
> --- a/Platform/ARM/JunoPkg/AcpiTables/AcpiSsdtRootPci.asl
> +++ b/Platform/ARM/JunoPkg/AcpiTables/AcpiSsdtRootPci.asl
> @@ -140,6 +140,19 @@ DefinitionBlock("SsdtPci.aml", "SSDT", 1, "ARMLTD", "ARM-JUNO", EFI_ACPI_ARM_OEM
>           Return (RBUF)
>         } // Method(_CRS)
>
> +      Device (RES0) {
> +        Name (_HID, "PNP0C02" /* PNP Motherboard Resources */)  // _HID: Hardware ID
> +        Name (_CRS, ResourceTemplate () {                       // _CRS: Current Resource Settings
> +           QWordMemory (ResourceProducer, PosDecode, MinFixed, MaxFixed, NonCacheable, ReadWrite,
> +           0x0000000000000000,                                  // Granularity
> +           FixedPcdGet64 (PcdPciExpressBaseAddress),            // Range Minimum
> +           FixedPcdGet64 (PcdPciConfigurationSpaceLimit),       // Range Maximum
> +           0x0000000000000000,                                  // Translation Offset
> +           FixedPcdGet64 (PcdPciConfigurationSpaceSize),        // Length
> +           ,, , AddressRangeMemory, TypeStatic)
> +        })
> +      }
> +
>         //
>         // OS Control Handoff
>         //

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