Hello. This patch series adds a feature that displays the link status of the CXL1.1 device. CXL devices are extensions of PCIe. Therefore, from CXL2.0 onwards, the link status can be output in the same way as traditional PCIe. However, unlike devices from CXL2.0 onwards, CXL1.1 requires a different method to obtain the link status from traditional PCIe. This is because the link status of the CXL1.1 device is not mapped in the configuration space (as per cxl3.0 specification 8.1). Instead, the configuration space containing the link status is mapped to the memory mapped register region (as per cxl3.0 specification 8.2, Table 8-18). Therefore, the current lspci has a problem where it does not display the link status of the CXL1.1 device. This patch solves these issues. The procedure is as follows: First, obtain the RCRB address within the cxl driver, then access the configuration space. Next, output the link status information from the configuration space to sysfs. Finally, read sysfs within lspci to display the link status information. Changes v1[1] -> v2: The following are the main changes made based on the feedback from Dan Williams. - Modified to perform rcrb access within the CXL driver. - Added new attributes to the sysfs of the PCI device. - Output the link status information to the sysfs of the PCI device. - Retrieve information from sysfs as the source when displaying information in lspci. v2[2] -> v3: - Fix unnecessary initialization and wrong types (Bjohn). - Create a helper function for getting a PCIe capability offset (Bjohn). - Move platform-specific implementation to the lib directory in pciutils (Martin). [1] https://lore.kernel.org/linux-cxl/20231220050738.178481-1-kobayashi.da-06@xxxxxxxxxxx/ [2] https://lore.kernel.org/linux-cxl/20240227083313.87699-1-kobayashi.da-06@xxxxxxxxxxx/ Kobayashi,Daisuke (3): Add sysfs attribute for CXL 1.1 device link status Remove conditional branch that is not suitable for cxl1.1 devices drivers/cxl/acpi.c | 4 - drivers/cxl/pci.c | 193 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 193 insertions(+), 4 deletions(-) Add function to display cxl1.1 device link status lib/access.c | 29 +++++++++++++++++++++ lib/pci.h | 2 ++ ls-caps.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 104 insertions(+) -- 2.43.0
