[v4,0/2] PCI: add enabe(disable)_device() hook for bridge

Message

Frank Li Nov. 1, 2024, 9:04 p.m. UTC

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/[e-mail]/
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 <[e-mail]>
To: Richard Zhu <[e-mail]>
To: Lucas Stach <[e-mail]>
To: Lorenzo Pieralisi <[e-mail]>
To: Krzysztof Wilczyński <[e-mail]>
To: Manivannan Sadhasivam <[e-mail]>
To: Rob Herring <[e-mail]>
To: Shawn Guo <[e-mail]>
To: Sascha Hauer <[e-mail]>
To: Pengutronix Kernel Team <[e-mail]>
To: Fabio Estevam <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
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Cc: [e-mail] \
Cc: [e-mail] \
Cc: Robin Murphy <[e-mail]>

Signed-off-by: Frank Li <[e-mail]>
---
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/[e-mail]

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/[e-mail]

Changes in v2:
- see each patch
- Link to v1: https://lore.kernel.org/r/[e-mail]

---
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 | 177 +++++++++++++++++++++++++++++++++-
 drivers/pci/pci.c                     |  23 ++++-
 include/linux/pci.h                   |   2 +
 3 files changed, 200 insertions(+), 2 deletions(-)
---
base-commit: 9a6b4af5bc27c1d3e5dc9f7fb0edd26047bb74ed
change-id: 20240926-imx95_lut-1c68222e0944

Best regards,
---
Frank Li <[e-mail]>