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| author | Danilo Krummrich <dakr@kernel.org> | 2026-08-13 18:52:04 +0200 |
|---|---|---|
| committer | Danilo Krummrich <dakr@kernel.org> | 2026-08-17 01:41:36 +0200 |
| commit | f146c7bc85a51f95c05e0f8173d484eb301ece78 (patch) | |
| tree | 07296ae54ed6551492b0c609dc0f5463f61f89ca /drivers/bcma/README | |
| download | linux-stable-f146c7bc85a51f95c05e0f8173d484eb301ece78.tar.gz linux-stable-f146c7bc85a51f95c05e0f8173d484eb301ece78.zip | |
PCI: Add pci_irq_type() to query the allocated interrupt typegrafted
Add a helper that returns PCI_IRQ_MSIX, PCI_IRQ_MSI, or PCI_IRQ_INTX
based on the interrupt type the PCI core selected after
pci_alloc_irq_vectors().
Several drivers already open-code this check against pdev->msix_enabled
and pdev->msi_enabled, or even open code this helper [1].
A common helper avoids the duplication and keeps drivers from accessing
the bitfield directly (see also [2]).
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Link: https://elixir.bootlin.com/linux/v7.1/source/drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c#L196 [1]
Inspired-by: John Hubbard <jhubbard@nvidia.com>
Link: https://lore.kernel.org/all/DKKG2QM3YJYB.Z2H2B2UXJ75N@kernel.org/ [2]
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260813165234.620555-5-dakr@kernel.org
[ Add missing pci_irq_type() stub for CONFIG_PCI=n. ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Diffstat (limited to 'drivers/bcma/README')
| -rw-r--r-- | drivers/bcma/README | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/drivers/bcma/README b/drivers/bcma/README new file mode 100644 index 000000000..f7e7ce46c --- /dev/null +++ b/drivers/bcma/README @@ -0,0 +1,19 @@ +Broadcom introduced new bus as replacement for older SSB. It is based on AMBA, +however from programming point of view there is nothing AMBA specific we use. + +Standard AMBA drivers are platform specific, have hardcoded addresses and use +AMBA standard fields like CID and PID. + +In case of Broadcom's cards every device consists of: +1) Broadcom specific AMBA device. It is put on AMBA bus, but can not be treated + as standard AMBA device. Reading it's CID or PID can cause machine lockup. +2) AMBA standard devices called ports or wrappers. They have CIDs (AMBA_CID) + and PIDs (0x103BB369), but we do not use that info for anything. One of that + devices is used for managing Broadcom specific core. + +Addresses of AMBA devices are not hardcoded in driver and have to be read from +EPROM. + +In this situation we decided to introduce separated bus. It can contain up to +16 devices identified by Broadcom specific fields: manufacturer, id, revision +and class. |