linux-kernel - Re: [PATCH v5 0/2] PCI: add enabe(disable)

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Message-ID: <ZzTL/b4BEAGvSa1Q@lizhi-Precision-Tower-5810>
Date: Wed, 13 Nov 2024 10:55:41 -0500
From: Frank Li <Frank.li@....com>
To: Bjorn Helgaas <bhelgaas@...gle.com>, Richard Zhu <hongxing.zhu@....com>,
	Lucas Stach <l.stach@...gutronix.de>,
	Lorenzo Pieralisi <lpieralisi@...nel.org>,
	Krzysztof Wilczyński <kw@...ux.com>,
	Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
	Rob Herring <robh@...nel.org>, Shawn Guo <shawnguo@...nel.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Pengutronix Kernel Team <kernel@...gutronix.de>,
	Fabio Estevam <festevam@...il.com>
Cc: linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, imx@...ts.linux.dev,
	alyssa@...enzweig.io, bpf@...r.kernel.org, broonie@...nel.org,
	jgg@...pe.ca, joro@...tes.org, lgirdwood@...il.com, maz@...nel.org,
	p.zabel@...gutronix.de, robin.murphy@....com, will@...nel.org
Subject: Re: [PATCH v5 0/2] PCI: add enabe(disable)_device() hook for bridge

On Mon, Nov 04, 2024 at 02:22:58PM -0500, Frank Li wrote:

Any comments for this patches?

Bjorn and give ack at v4 and Marc Zyngier give test/review tag at v4. I
just drop these because change to use helper function and funtionality is
the same.

After this patch merge, I think apply's bus notification can convert to
this way.

Frank

> Some system's IOMMU stream(master) ID bits(such as 6bits) less than
> pci_device_id (16bit). It needs add hardware configuration to enable
> pci_device_id to stream ID convert.
>
> https://lore.kernel.org/imx/20240622173849.GA1432357@bhelgaas/
> This ways use pcie bus notifier (like apple pci controller), when new PCIe
> device added, bus notifier will call register specific callback to handle
> look up table (LUT) configuration.
>
> https://lore.kernel.org/imx/20240429150842.GC1709920-robh@kernel.org/
> which parse dt's 'msi-map' and 'iommu-map' property to static config LUT
> table (qcom use this way). This way is rejected by DT maintainer Rob.
>
> Above ways can resolve LUT take or stream id out of usage the problem. If
> there are not enough stream id resource, not error return, EP hardware
> still issue DMA to do transfer, which may transfer to wrong possition.
>
> Add enable(disable)_device() hook for bridge can return error when not
> enough resource, and PCI device can't enabled.
>
> Basicallly this version can match Bjorn's requirement:
> 1: simple, because it is rare that there are no LUT resource.
> 2: EP driver probe failure when no LUT, but lspci can see such device.
>
> [    2.164415] nvme nvme0: pci function 0000:01:00.0
> [    2.169142] pci 0000:00:00.0: Error enabling bridge (-1), continuing
> [    2.175654] nvme 0000:01:00.0: probe with driver nvme failed with error -12
>
> > lspci
> 0000:00:00.0 PCI bridge: Philips Semiconductors Device 0000
> 0000:01:00.0 Non-Volatile memory controller: Micron Technology Inc 2100AI NVMe SSD [Nitro] (rev 03)
>
> To: Bjorn Helgaas <bhelgaas@...gle.com>
> To: Richard Zhu <hongxing.zhu@....com>
> To: Lucas Stach <l.stach@...gutronix.de>
> To: Lorenzo Pieralisi <lpieralisi@...nel.org>
> To: Krzysztof Wilczyński <kw@...ux.com>
> To: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
> To: Rob Herring <robh@...nel.org>
> To: Shawn Guo <shawnguo@...nel.org>
> To: Sascha Hauer <s.hauer@...gutronix.de>
> To: Pengutronix Kernel Team <kernel@...gutronix.de>
> To: Fabio Estevam <festevam@...il.com>
> Cc: linux-pci@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org
> Cc: linux-arm-kernel@...ts.infradead.org
> Cc: imx@...ts.linux.dev
> Cc: Frank.li@....com \
> Cc: alyssa@...enzweig.io \
> Cc: bpf@...r.kernel.org \
> Cc: broonie@...nel.org \
> Cc: jgg@...pe.ca \
> Cc: joro@...tes.org \
> Cc: l.stach@...gutronix.de \
> Cc: lgirdwood@...il.com \
> Cc: maz@...nel.org \
> Cc: p.zabel@...gutronix.de \
> Cc: robin.murphy@....com \
> Cc: will@...nel.org \
> Cc: Robin Murphy <robin.murphy@....com>
> Cc: Marc Zyngier <maz@...nel.org>
>
> Signed-off-by: Frank Li <Frank.Li@....com>
> ---
> Changes in v5:
> - Add help function of pci_bridge_enable(disable)_device
> - Because big change, removed Bjorn's review tags and have not
> added
> Marc Zyngier't review and test tags
> - Fix pci-imx6.c according to Mani's feedback
> - Link to v4: https://lore.kernel.org/r/20241101-imx95_lut-v4-0-0fdf9a2fe754@nxp.com
>
> Changes in v4:
> - Add Bjorn Helgaas review tag for patch1
> - check 'target' value for patch2
> - detail see each patches
> - Link to v3: https://lore.kernel.org/r/20241024-imx95_lut-v3-0-7509c9bbab86@nxp.com
>
> Changes in v3:
> - disable_device when error happen
> - use target for of_map_id
> - Check if rid already in lut table when enable deviced
> - Link to v2: https://lore.kernel.org/r/20240930-imx95_lut-v2-0-3b6467ba539a@nxp.com
>
> Changes in v2:
> - see each patch
> - Link to v1: https://lore.kernel.org/r/20240926-imx95_lut-v1-0-d0c62087dbab@nxp.com
>
> ---
> Frank Li (2):
>       PCI: Add enable_device() and disable_device() callbacks for bridges
>       PCI: imx6: Add IOMMU and ITS MSI support for i.MX95
>
>  drivers/pci/controller/dwc/pci-imx6.c | 176 +++++++++++++++++++++++++++++++++-
>  drivers/pci/pci.c                     |  36 ++++++-
>  include/linux/pci.h                   |   2 +
>  3 files changed, 212 insertions(+), 2 deletions(-)
> ---
> base-commit: 06fb071a1aefbe4c6cc8fd41aacd0b9422361721
> change-id: 20240926-imx95_lut-1c68222e0944
>
> Best regards,
> ---
> Frank Li <Frank.Li@....com>
>