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: c97006046c ("cxl/port: Read CDAT table")
Tested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: stable@vger.kernel.org # v6.0+
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/3051114102f41d19df3debbee123129118fc5e6d.1678543498.git.lukas@wunner.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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" <ming4.li@intel.com>
Cc: Bjorn Helgaas <helgaas@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Acked-by: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Co-developed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20220719205249.566684-4-ira.weiny@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Lukas Wunner