From: marc.zyngier@arm•com (Marc Zyngier)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH V4 4/7] ARM64, ACPI, PCI: I/O Remapping Table (IORT) initial support.
Date: Thu, 14 Apr 2016 12:48:18 +0100 [thread overview]
Message-ID: <570F8382.6040307@arm.com> (raw)
In-Reply-To: <32c49fc25832b4cee05e5c9352c2f6cf@codeaurora.org>
On 14/04/16 12:37, okaya at codeaurora.org wrote:
> On 2016-04-14 03:36, Marc Zyngier wrote:
>> On 14/04/16 08:20, Tomasz Nowicki wrote:
>>> On 13.04.2016 23:18, Sinan Kaya wrote:
>>>> On 4/13/2016 11:52 AM, Marc Zyngier wrote:
>>>>>>> Sure. Please see:
>>>>>>> http://infocenter.arm.com/help/topic/com.arm.doc.den0049a/DEN0049A_IO_Remapping_Table.pdf
>>>>>>> 3.1.1.5 PCI root complex node
>>>>>>> PCI Segment number -> The PCI segment number, as in MCFG and as
>>>>>>> returned by _SEG in the namespace.
>>>>>>>
>>>>>>> So IORT spec states that pci_segment_number corresponds to the
>>>>>>> segment
>>>>>>> number from MCFG table and _SEG method. Here is my patch which
>>>>>>> makes
>>>>>>> sure pci_domain_nr(bus) is set properly:
>>>>>>> https://lkml.org/lkml/2016/2/16/418
>>>>> Lovely. So this series is actually dependent on the PCI one. I guess
>>>>> we
>>>>> need to solve that one first, because IORT seems pretty pointless if
>>>>> we
>>>>> don't have PCI support. What's the plan?
>>>>
>>>> Would it be OK to split the PCI specific section of the patch and
>>>> continue
>>>> review? PCI is a user of the IORT table. Not the other way around.
>>>
>>> I need to disagree. What would be the use case for patches w/o "PCI
>>> part" ?
>>
>> Quite. PCI (as a subsystem) doesn't need IORT at all, thank you very
>> much. GIC (implementing MSI) and SMMU (implementing DMA) do, by virtue
>> of RID/SID/DID being translated all over the place.
>>
>> So by the look of it, the dependency chain is GIC+SMMU->IORT->PCI.
>>
>> The GIC changes here are pretty mechanical, and not that interesting.
>> The stuff that needs sorting quickly is PCI, because all this work is
>> pointless if we don't have it.
>>
>> At the risk of sounding like a stuck record: What's the plan?
>>
>> Thanks,
>>
>> M.
>
> My answer is based on the spec definition. The spec defines named
> components for other peripherals that are behind iommu and can
> potentially implement msi.
>
> You could have used a basic device like platform sata to take care of
> basic iort and smmu support.
>
> You can then come back and implement PCIe support.
I could. You could do it too. Thankfully, the dependency is dictated by
whoever is writing the code.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2016-04-14 11:48 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-04 8:52 [PATCH V4 0/7] Introduce ACPI world to ITS irqchip Tomasz Nowicki
2016-04-04 8:52 ` [PATCH V4 1/7] acpi, pci: Setup MSI domain on a per-devices basis Tomasz Nowicki
2016-04-13 10:18 ` Marc Zyngier
2016-04-13 10:49 ` Tomasz Nowicki
2016-04-04 8:52 ` [PATCH V4 2/7] irqchip, GICv3, ITS: Cleanup for ITS domain initialization Tomasz Nowicki
2016-04-13 14:18 ` Marc Zyngier
2016-04-04 8:52 ` [PATCH V4 3/7] irqchip, GICv3, ITS: Refator ITS DT init code to prepare for ACPI Tomasz Nowicki
2016-04-12 10:18 ` Tomasz Nowicki
2016-04-13 15:09 ` Marc Zyngier
2016-04-04 8:52 ` [PATCH V4 4/7] ARM64, ACPI, PCI: I/O Remapping Table (IORT) initial support Tomasz Nowicki
2016-04-13 15:23 ` Marc Zyngier
2016-04-13 15:36 ` Tomasz Nowicki
2016-04-13 15:52 ` Marc Zyngier
2016-04-13 21:18 ` Sinan Kaya
2016-04-14 7:20 ` Tomasz Nowicki
2016-04-14 7:36 ` Marc Zyngier
2016-04-14 11:37 ` okaya at codeaurora.org
2016-04-14 11:48 ` Marc Zyngier [this message]
2016-04-14 7:39 ` Tomasz Nowicki
2016-04-14 7:46 ` Marc Zyngier
2016-04-04 8:52 ` [PATCH V4 5/7] irqchip, gicv3, its: Probe ITS in the ACPI way Tomasz Nowicki
2016-04-14 9:01 ` Marc Zyngier
2016-04-04 8:52 ` [PATCH V4 6/7] its, pci, msi: Factor out code that might be reused for ACPI Tomasz Nowicki
2016-04-04 8:52 ` [PATCH V4 7/7] acpi, gicv3, its: Use MADT ITS subtable to do PCI/MSI domain initialization Tomasz Nowicki
2016-04-12 7:39 ` [PATCH V4 0/7] Introduce ACPI world to ITS irqchip Tomasz Nowicki
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