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);
