[PATCH v3 01/10] PCI: Protect Link Control 2 Register with RMW locking

Ilpo Järvinen
2023-09-29T11:57:57Z

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@linux.intel.com>
---
Documentation/PCI/pciebus-howto.rst | 8 ++++----
include/linux/pci.h | 1 +
2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/Documentation/PCI/pciebus-howto.rst b/Documentation/PCI/pciebus-howto.rst
index a0027e8fb0d0..3ba322ca1ce1 100644
--- a/Documentation/PCI/pciebus-howto.rst
+++ b/Documentation/PCI/pciebus-howto.rst
@@ -218,7 +218,7 @@ 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().
+Register, Root Control Register, and 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().
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 8c7c2c3c6c65..16db80f8b15c 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1243,6 +1243,7 @@ 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);
--
2.30.2