From: Robin Murphy <robin.murphy@arm.com>
To: Laurentiu Tudor <laurentiu.tudor@nxp.com>,
Li Yang <leoyang.li@nxp.com>, Olof Johansson <olof@lixom.net>
Cc: "mark.rutland@arm.com" <mark.rutland@arm.com>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
"arnd@arndb.de" <arnd@arndb.de>,
"m.karthikeyan@mobiveil.co.in" <m.karthikeyan@mobiveil.co.in>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"Z.q. Hou" <zhiqiang.hou@nxp.com>,
"l.subrahmanya@mobiveil.co.in" <l.subrahmanya@mobiveil.co.in>,
"will.deacon@arm.com" <will.deacon@arm.com>,
Russell King - ARM Linux admin <linux@armlinux.org.uk>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Diana Madalina Craciun <diana.craciun@nxp.com>,
"M.h. Lian" <minghuan.lian@nxp.com>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
Xiaowei Bao <xiaowei.bao@nxp.com>,
"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
"bhelgaas@google.com" <bhelgaas@google.com>,
"andrew.murray@arm.com" <andrew.murray@arm.com>,
"shawnguo@kernel.org" <shawnguo@kernel.org>,
Mingkai Hu <mingkai.hu@nxp.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCHv9 00/12] PCI: Recode Mobiveil driver and add PCIe Gen4 driver for NXP Layerscape SoCs
Date: Tue, 11 Feb 2020 14:51:01 +0000 [thread overview]
Message-ID: <60272422-b4c8-a86a-fa73-c158f723acb4@arm.com> (raw)
In-Reply-To: <27e0acfc-0782-bd97-a80e-1143f1315891@nxp.com>
On 11/02/2020 1:55 pm, Laurentiu Tudor wrote:
>
>
> On 11.02.2020 15:04, Robin Murphy wrote:
>> On 2020-02-11 12:13 pm, Laurentiu Tudor wrote:
>> [...]
>>>> This is a known issue about DPAA2 MC bus not working well with SMMU
>>>> based IO mapping. Adding Laurentiu to the chain who has been looking
>>>> into this issue.
>>>
>>> Yes, I'm closely following the issue. I actually have a workaround
>>> (attached) but haven't submitted as it will probably raise a lot of
>>> eyebrows. In the mean time I'm following some discussions [1][2][3]
>>> on the iommu list which seem to try to tackle what appears to be a
>>> similar issue but with framebuffers. My hope is that we will be able
>>> to leverage whatever turns out.
>>
>> Indeed it's more general than framebuffers - in fact there was a
>> specific requirement from the IORT side to accommodate network/storage
>> controllers with in-memory firmware/configuration data/whatever set up
>> by the bootloader that want to be handed off 'live' to Linux because
>> the overhead of stopping and restarting them is impractical. Thus this
>> DPAA2 setup is very much within scope of the desired solution, so
>> please feel free to join in (particularly on the DT parts) :)
>
> Will sure do. Seems that the 2nd approach (the one with list of
> compatibles in arm-smmu) fits really well with our scenario. Will this
> be the way to go forward?
I'm hoping that Thierry's proposal can be made to work out, since it's
closer to how the ACPI version should work, which means we would be able
to do a lot more in shared common code rather than baking magic
knowledge and duplicated functionality into individual IOMMU drivers.
>> As for right now, note that your patch would only be a partial
>> mitigation to slightly reduce the fault window but not remove it
>> entirely. To be robust the SMMU driver *has* to know about live
>> streams before the first arm_smmu_reset() - hence the need for generic
>> firmware bindings - so doing anything from the MC driver is already
>> too late (and indeed the current iommu_request_dm_for_dev() mechanism
>> is itself a microcosm of the same problem).
>
> I think you might have missed in the patch that it pauses the firmware
> at early boot, in its driver init and it resumes it only after
> iommu_request_dm_for_dev() has completed. :)
Ah, from the context I missed that that was non-modular and relying on
initcall trickery... fair enough, in that case I'll downgrade my "it's
insufficient" to "it's ugly and somewhat fragile" :P
Thanks,
Robin.
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next prev parent reply other threads:[~2020-02-11 14:51 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-20 3:45 [PATCHv9 00/12] PCI: Recode Mobiveil driver and add PCIe Gen4 driver for NXP Layerscape SoCs Z.q. Hou
2019-11-20 3:45 ` [PATCHv9 01/12] PCI: mobiveil: Re-abstract the private structure Z.q. Hou
2020-01-13 10:09 ` Andrew Murray
2020-02-06 11:04 ` Z.q. Hou
2020-02-06 11:27 ` Andrew Murray
2019-11-20 3:45 ` [PATCHv9 02/12] PCI: mobiveil: Move the host initialization into a routine Z.q. Hou
2020-01-13 10:19 ` Andrew Murray
2020-02-06 11:14 ` Z.q. Hou
2019-11-20 3:45 ` [PATCHv9 03/12] PCI: mobiveil: Collect the interrupt related operations " Z.q. Hou
2020-01-13 10:34 ` Andrew Murray
2020-02-06 11:30 ` Z.q. Hou
2019-11-20 3:45 ` [PATCHv9 04/12] PCI: mobiveil: Modularize the Mobiveil PCIe Host Bridge IP driver Z.q. Hou
2020-01-13 11:05 ` Andrew Murray
2020-02-06 12:25 ` Z.q. Hou
2019-11-20 3:45 ` [PATCHv9 05/12] PCI: mobiveil: Add callback function for interrupt initialization Z.q. Hou
2020-01-13 11:19 ` Andrew Murray
2020-02-06 13:25 ` Z.q. Hou
2019-11-20 3:45 ` [PATCHv9 06/12] PCI: mobiveil: Add callback function for link up check Z.q. Hou
2020-01-13 11:22 ` Andrew Murray
2020-02-06 13:25 ` Z.q. Hou
2019-11-20 3:46 ` [PATCHv9 07/12] PCI: mobiveil: Make mobiveil_host_init() can be used to re-init host Z.q. Hou
2020-01-13 11:26 ` Andrew Murray
2020-02-06 13:27 ` Z.q. Hou
2019-11-20 3:46 ` [PATCHv9 08/12] PCI: mobiveil: Add 8-bit and 16-bit CSR register accessors Z.q. Hou
2020-01-13 11:31 ` Andrew Murray
2020-02-06 13:45 ` Z.q. Hou
2019-11-20 3:46 ` [PATCHv9 09/12] dt-bindings: PCI: Add NXP Layerscape SoCs PCIe Gen4 controller Z.q. Hou
2019-11-20 3:46 ` [PATCHv9 10/12] PCI: mobiveil: Add PCIe Gen4 RC driver for NXP Layerscape SoCs Z.q. Hou
2020-01-13 12:02 ` Andrew Murray
2020-02-06 13:45 ` Z.q. Hou
2020-02-06 14:29 ` Andrew Murray
2019-11-20 3:46 ` [PATCHv9 11/12] arm64: dts: lx2160a: Add PCIe controller DT nodes Z.q. Hou
2019-11-20 3:46 ` [PATCHv9 12/12] arm64: defconfig: Enable CONFIG_PCIE_LAYERSCAPE_GEN4 Z.q. Hou
2019-11-20 9:57 ` [PATCHv9 00/12] PCI: Recode Mobiveil driver and add PCIe Gen4 driver for NXP Layerscape SoCs Russell King - ARM Linux admin
2019-11-20 10:30 ` Z.q. Hou
2019-12-13 18:37 ` Olof Johansson
2019-12-17 2:50 ` Z.q. Hou
2020-01-10 15:33 ` Lorenzo Pieralisi
2020-01-10 17:05 ` Olof Johansson
2020-02-06 10:57 ` Z.q. Hou
2020-02-10 15:12 ` Olof Johansson
2020-02-10 15:22 ` Russell King - ARM Linux admin
2020-02-10 15:28 ` Olof Johansson
2020-02-10 16:15 ` Russell King - ARM Linux admin
2020-02-10 17:20 ` Russell King - ARM Linux admin
2020-02-10 18:33 ` Olof Johansson
2020-02-10 18:41 ` Li Yang
2020-02-10 19:48 ` Li Yang
2020-02-11 12:13 ` Laurentiu Tudor
2020-02-11 13:04 ` Robin Murphy
2020-02-11 13:55 ` Laurentiu Tudor
2020-02-11 14:51 ` Robin Murphy [this message]
2020-02-11 14:48 ` Olof Johansson
2020-02-11 15:14 ` Laurentiu Tudor
2020-02-29 9:55 ` Russell King - ARM Linux admin
2020-02-29 11:04 ` Russell King - ARM Linux admin
2020-02-29 12:08 ` Russell King - ARM Linux admin
2020-02-29 13:32 ` Russell King - ARM Linux admin
2020-02-29 15:19 ` Theodore Y. Ts'o
2020-02-29 17:03 ` Russell King - ARM Linux admin
2020-02-29 18:03 ` Theodore Y. Ts'o
2020-06-05 23:53 ` Russell King - ARM Linux admin
2020-06-06 10:19 ` Russell King - ARM Linux admin
2020-02-10 15:33 ` Lorenzo Pieralisi
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