Re: [PATCH 1/1] Platform/RaspberryPi: Add linux quirk support

Andrei Warkentin

Hi Jeremy,

Reviewed-by: Andrei Warkentin <awarkentin@...>


Root port registers would be NonCacheable just like the outbound mapping. (Also, with, _MEM attributes aside from  NonCacheable and Prefetchable are effectively deprecated).

Note: I really wish we had sorted out the HID/CID story for the PCIe RC... i.e. at least to make the HID custom for non-ECAM implementations and push PNP0A08/PNP0A03 in the CID... this would make linux,pcie-quirk unnecessary, using standard ACPI driver binding mechanisms to separate quirks from proper ECAM. Sadly, I think the train to do that has long left the station (with so many ACPI Arm systems out there and non-ECAM or not-quite-ECAM RCs using PNP0A08/PNP0A03 alone. ESXi, for example, ends up keying on the Table Ids (which is arguably even worse than the DT props)

Note 2: Given that DT has users in U-Boot and the BSDs (and potentially anywhere else), there's a long term hope to make DT bindings separate from Linux. To that end "linux,pcie-quirk" and "linux,pcie-nomsi" should probably be named something else (although I recognise that you're probably just wiring up something that already exists).

Andrei Warkentin,
Arm Enablement Architect,
Cloud Platform Business Unit, VMware

From: Jeremy Linton <jeremy.linton@...>
Sent: Thursday, August 5, 2021 7:40 PM
To: <>
Cc: pete@... <pete@...>; ardb+tianocore@... <ardb+tianocore@...>; Andrei Warkentin <awarkentin@...>; Sunny.Wang@... <Sunny.Wang@...>; samer.el-haj-mahmoud@... <samer.el-haj-mahmoud@...>; Jeremy Linton <jeremy.linton@...>
Subject: [PATCH 1/1] Platform/RaspberryPi: Add linux quirk support
Linux, for the time being has refused to support the Arm
standard SMCCC for PCIe configuration. Instead they
want to continue to maintain per device "quirks".

As the RPI isn't really ECAM this is a bit more
involved because the MADT can't really describe
the root port+config registers situation. Further
platforms which support the SMCCC shouldn't have
a MADT, so we need an additional way to tell linux
what it needs to know about this platform.

Signed-off-by: Jeremy Linton <jeremy.linton@...>
 Platform/RaspberryPi/AcpiTables/Pci.asl | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/Platform/RaspberryPi/AcpiTables/Pci.asl b/Platform/RaspberryPi/AcpiTables/Pci.asl
index 34474f13ef..3e7fd0d5b7 100644
--- a/Platform/RaspberryPi/AcpiTables/Pci.asl
+++ b/Platform/RaspberryPi/AcpiTables/Pci.asl
@@ -123,6 +123,15 @@ DefinitionBlock (__FILE__, "SSDT", 5, "RPIFDN", "RPI4PCIE", 2)
         Name(_BBN, Zero) // PCI Base Bus Number
         Name(_CCA, 0)    // Mark the PCI noncoherent
+        Name (_DSD, Package () {
+          ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+            Package () {
+              Package () { "linux,pcie-quirk", "bcm2711" },
+              Package () { "linux,pcie-nomsi", 1 },
+            }
+        })
         // Root Complex 0
         Device (RP0) {
          Name(_ADR, 0xF0000000)    // Dev 0, Func 0
@@ -176,6 +185,18 @@ DefinitionBlock (__FILE__, "SSDT", 5, "RPIFDN", "RPI4PCIE", 2)
               2                               // SANITIZED_PCIE_MMIO_LEN + 1
+            QWordMemory ( // Root port registers, not to be used if SMCCC is utilized
+              ResourceConsumer, ,
+              MinFixed, MaxFixed,
+              NonCacheable, ReadWrite,        // cacheable? is that right?
+              0x00000000,                     // Granularity
+              0xFD500000,                     // Root port begin
+              0xFD509FFF,                     // Root port end
+              0x00000000,                     // no translation
+              0x0000A000,                     // size
+              ,,
+            )
           }) // end Name(RBUF)
           // Work around ASL's inability to add in a resource definition

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