cxl/pci: Fix CDAT retrieval on big endian

2023-04-13T14:55:24+00:00

commit fbaa38214cd9e150764ccaa82e04ecf42cc1140c upstream. The CDAT exposed in sysfs differs between little endian and big endian arches: On big endian, every 4 bytes are byte-swapped. PCI Configuration Space is little endian (PCI r3.0 sec 6.1). Accessors such as pci_read_config_dword() implicitly swap bytes on big endian. That way, the macros in include/uapi/linux/pci_regs.h work regardless of the arch's endianness. For an example of implicit byte-swapping, see ppc4xx_pciex_read_config(), which calls in_le32(), which uses lwbrx (Load Word Byte-Reverse Indexed). DOE Read/Write Data Mailbox Registers are unlike other registers in Configuration Space in that they contain or receive a 4 byte portion of an opaque byte stream (a "Data Object" per PCIe r6.0 sec 7.9.24.5f). They need to be copied to or from the request/response buffer verbatim. So amend pci_doe_send_req() and pci_doe_recv_resp() to undo the implicit byte-swapping. The CXL_DOE_TABLE_ACCESS_* and PCI_DOE_DATA_OBJECT_DISC_* macros assume implicit byte-swapping. Byte-swap requests after constructing them with those macros and byte-swap responses before parsing them. Change the request and response type to __le32 to avoid sparse warnings. Per a request from Jonathan, replace sizeof(u32) with sizeof(__le32) for consistency. Fixes: c97006046c79 ("cxl/port: Read CDAT table") Tested-by: Ira Weiny Signed-off-by: Lukas Wunner Reviewed-by: Dan Williams Cc: stable@vger.kernel.org # v6.0+ Reviewed-by: Jonathan Cameron Link: https://lore.kernel.org/r/3051114102f41d19df3debbee123129118fc5e6d.1678543498.git.lukas@wunner.de Signed-off-by: Dan Williams Signed-off-by: Greg Kroah-Hartman

PCI/DOE: Add DOE mailbox support functions

2022-07-19T22:38:04+00:00

Introduced in a PCIe r6.0, sec 6.30, DOE provides a config space based mailbox with standard protocol discovery. Each mailbox is accessed through a DOE Extended Capability. Each DOE mailbox must support the DOE discovery protocol in addition to any number of additional protocols. Define core PCIe functionality to manage a single PCIe DOE mailbox at a defined config space offset. Functionality includes iterating, creating, query of supported protocol, and task submission. Destruction of the mailboxes is device managed. Cc: "Li, Ming" Cc: Bjorn Helgaas Cc: Matthew Wilcox Acked-by: Bjorn Helgaas Signed-off-by: Jonathan Cameron Co-developed-by: Ira Weiny Signed-off-by: Ira Weiny Link: https://lore.kernel.org/r/20220719205249.566684-4-ira.weiny@intel.com Signed-off-by: Dan Williams

kernel/linux.git/include/linux/pci-doe.h, branch v6.1.168

cxl/pci: Fix CDAT retrieval on big endian

PCI/DOE: Add DOE mailbox support functions