On Wed, 9 Oct 2024 12:52:16 +0300 Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> wrote: > PCIe Bandwidth Controller performs RMW accesses the Link Control 2 > Register which can occur concurrently to other sources of Link Control > 2 Register writes. Therefore, add Link Control 2 Register among the PCI > Express Capability Registers that need RMW locking. > > Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> > Reviewed-by: Lukas Wunner <lukas@xxxxxxxxx> Totally trivial comment inline. LGTM Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > --- > Documentation/PCI/pciebus-howto.rst | 14 +++++++++----- > include/linux/pci.h | 1 + > 2 files changed, 10 insertions(+), 5 deletions(-) > > diff --git a/Documentation/PCI/pciebus-howto.rst b/Documentation/PCI/pciebus-howto.rst > index f344452651e1..375d9ce171f6 100644 > --- a/Documentation/PCI/pciebus-howto.rst > +++ b/Documentation/PCI/pciebus-howto.rst > @@ -217,8 +217,12 @@ capability structure except the PCI Express capability structure, > that is shared between many drivers including the service drivers. > RMW Capability accessors (pcie_capability_clear_and_set_word(), > pcie_capability_set_word(), and pcie_capability_clear_word()) protect > -a selected set of PCI Express Capability Registers (Link Control > -Register and Root Control Register). Any change to those registers > -should be performed using RMW accessors to avoid problems due to > -concurrent updates. For the up-to-date list of protected registers, > -see pcie_capability_clear_and_set_word(). > +a selected set of PCI Express Capability Registers: > + > +* Link Control Register > +* Root Control Register > +* Link Control 2 Register > + > +Any change to those registers should be performed using RMW accessors to > +avoid problems due to concurrent updates. For the up-to-date list of > +protected registers, see pcie_capability_clear_and_set_word(). If I were super fussy I'd ask for a precursor patch doing the reformat. Meh - up to Bjorn, but for me this is small enough to not be worth the effort. > diff --git a/include/linux/pci.h b/include/linux/pci.h > index 573b4c4c2be6..be5ed534c39c 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1274,6 +1274,7 @@ static inline int pcie_capability_clear_and_set_word(struct pci_dev *dev, > { > switch (pos) { > case PCI_EXP_LNKCTL: > + case PCI_EXP_LNKCTL2: > case PCI_EXP_RTCTL: > return pcie_capability_clear_and_set_word_locked(dev, pos, > clear, set);