cxl/pci: Get rid of pointer arithmetic reading CDAT table

Reading the CDAT table using DOE requires a Table Access Response
Header in addition to the CDAT entry. In current implementation this
has caused offsets with sizeof(__le32) to the actual buffers. This led
to hardly readable code and even bugs. E.g., see fix of devm_kfree()
in read_cdat_data():

commit c65efe3685f5 ("cxl/cdat: Free correct buffer on checksum error")

Rework code to avoid calculations with sizeof(__le32). Introduce
struct cdat_doe_rsp for this which contains the Table Access Response
Header and a variable payload size for various data structures
afterwards to access the CDAT table and its CDAT Data Structures
without recalculating buffer offsets.

Cc: Lukas Wunner <lukas@wunner.de>
Cc: Fan Ni <nifan.cxl@gmail.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Robert Richter <rrichter@amd.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240216155844.406996-3-rrichter@amd.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl: Calculate and store PCI link latency for the downstream ports

The latency is calculated by dividing the flit size over the bandwidth. Add
support to retrieve the flit size for the CXL switch device and calculate
the latency of the PCIe link. Cache the latency number with cxl_dport.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/170319621931.2212653.6800240203604822886.stgit@djiang5-mobl3
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl/pci: Find and register CXL PMU devices

CXL PMU devices can be found from entries in the Register
Locator DVSEC.

Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20230526095824.16336-4-Jonathan.Cameron@huawei.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl: Wait Memory_Info_Valid before access memory related info

The Memory_Info_Valid bit (CXL 3.0 8.1.3.8.2) indicates that the CXL
Range Size High and Size Low registers are valid. The bit must be set
within 1 second of reset deassertion to the device. Check valid bit
before we check the Memory_Active bit when waiting for
cxl_await_media_ready() to ensure that the memory info is valid for
consumption. Also ensures both DVSEC ranges 1 and 2 are ready if DVSEC
Capability indicates they are both supported.

Fixes: 523e594d9cc0 ("cxl/pci: Implement wait for media active")
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/168444687469.3134781.11033518965387297327.stgit@djiang5-mobl3
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl/pci: Handle truncated CDAT entries

If truncated CDAT entries are received from a device, the concatenation
of those entries constitutes a corrupt CDAT, yet is happily exposed to
user space.

Avoid by verifying response lengths and erroring out if truncation is
detected.

The last CDAT entry may still be truncated despite the checks introduced
herein if the length in the CDAT header is too small. However, that is
easily detectable by user space because it reaches EOF prematurely.
A subsequent commit which rightsizes the CDAT response allocation closes
that remaining loophole.

The two lines introduced here which exceed 80 chars are shortened to
less than 80 chars by a subsequent commit which migrates to a
synchronous DOE API and replaces "t.task.rv" by "rc".

The existing acpi_cdat_header and acpi_table_cdat struct definitions
provided by ACPICA cannot be used because they do not employ __le16 or
__le32 types. I believe that cannot be changed because those types are
Linux-specific and ACPI is specified for little endian platforms only,
hence doesn't care about endianness. So duplicate the structs.

Fixes: c97006046c79 ("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>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: stable@vger.kernel.org # v6.0+
Link: https://lore.kernel.org/r/bce3aebc0e8e18a1173425a7a865b232c3912963.1678543498.git.lukas@wunner.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl/port: Export cxl_dvsec_rr_decode() to cxl_port

Call cxl_dvsec_rr_decode() in the beginning of cxl_port_probe() and
preserve the decoded information in a local
'struct cxl_endpoint_dvsec_info'. This info can be passed to various
functions later on in order to support the HDM decoder emulation.
The invocation of cxl_dvsec_rr_decode() in cxl_hdm_decode_init() is
removed and a pointer to the 'struct cxl_endpoint_dvsec_info' is passed
in.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/167640367377.935665.2848747799651019676.stgit@dwillia2-xfh.jf.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl/mem: Wire up event interrupts

Currently the only CXL features targeted for irq support require their
message numbers to be within the first 16 entries. The device may
however support less than 16 entries depending on the support it
provides.

Attempt to allocate these 16 irq vectors. If the device supports less
then the PCI infrastructure will allocate that number. Upon successful
allocation, users can plug in their respective isr at any point
thereafter.

CXL device events are signaled via interrupts. Each event log may have
a different interrupt message number. These message numbers are
reported in the Get Event Interrupt Policy mailbox command.

Add interrupt support for event logs. Interrupts are allocated as
shared interrupts. Therefore, all or some event logs can share the same
message number.

In addition all logs are queried on any interrupt in order of the most
to least severe based on the status register.

Finally place all event configuration logic into cxl_event_config().
Previously the logic was a simple 'read all' on start up. But
interrupts must be configured prior to any reads to ensure no events are
missed. A single event configuration function results in a cleaner over
all implementation.

Cc: Bjorn Helgaas <helgaas@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Co-developed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20221216-cxl-ev-log-v7-2-2316a5c8f7d8@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl/pci: Move tracepoint definitions to drivers/cxl/core/

CXL is using tracepoints for reporting RAS capability register payloads
for AER events, and has plans to use tracepoints for the output payload
of Get Poison List and Get Event Records commands. For organization
purposes it would be nice to keep those all under a single + local CXL
trace system. This also organization also potentially helps in the
future when CXL drivers expand beyond generic memory expanders, however
that would also entail a move away from the expander-specific
cxl_dev_state context, save that for later.

Note that the powerpc-specific drivers/misc/cxl/ also defines a 'cxl'
trace system, however, it is unlikely that a single platform will ever
load both drivers simultaneously.

Cc: Steven Rostedt <rostedt@goodmis.org>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/167051869176.436579.9728373544811641087.stgit@dwillia2-xfh.jf.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl/core/regs: Make cxl_map_{component, device}_regs() device generic

There is no need to carry the barno and the block offset through the
stack, just convert them to a resource base immediately.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/166974411035.1608150.8605988708101648442.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl/port: Read CDAT table

The per-device CDAT data provides performance data that is relevant for
mapping which CXL devices can participate in which CXL ranges by QTG
(QoS Throttling Group) (per ECN: CXL 2.0 CEDT CFMWS & QTG_DSM) [1]. The
QTG association specified in the ECN is advisory. Until the
cxl_acpi driver grows support for invoking the QTG _DSM method the CDAT
data is only of interest to userspace that may need it for debug
purposes.

Search the DOE mailboxes available, query CDAT data, cache the data and
make it available via a sysfs binary attribute per endpoint at:

/sys/bus/cxl/devices/endpointX/CDAT

...similar to other ACPI-structured table data in
/sys/firmware/ACPI/tables. The CDAT is relative to 'struct cxl_port'
objects since switches in addition to endpoints can host a CDAT
instance. Switch CDAT support is not implemented.

This does not support table updates at runtime. It will always provide
whatever was there when first cached. It is also the case that table
updates are not expected outside of explicit DPA address map affecting
commands like Set Partition with the immediate flag set. Given that the
driver does not support Set Partition with the immediate flag set there
is no current need for update support.

Link: https://www.computeexpresslink.org/spec-landing [1]
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Co-developed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
[djbw: drop in-kernel parsing infra for now, and other minor fixups]
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20220719205249.566684-7-ira.weiny@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl/port: Reuse 'struct cxl_hdm' context for hdm init

The port driver maps component registers for port operations. Reuse that
mapping for HDM Decoder Capability setup / enable. Move
devm_cxl_setup_hdm() before cxl_hdm_decode_init() and plumb @cxlhdm
through the hdm init helpers.

Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/165291691712.1426646.14336397551571515480.stgit@dwillia2-xfh
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl/pci: Drop @info argument to cxl_hdm_decode_init()

Now that nothing external to cxl_hdm_decode_init() considers
'struct cxl_endpoint_dvec_info' move it internal to
cxl_hdm_decode_init().

Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/165291690612.1426646.7866084245521113414.stgit@dwillia2-xfh
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl/mem: Merge cxl_dvsec_ranges() and cxl_hdm_decode_init()

In preparation for changing how the driver handles 'mem_enable' in the CXL
DVSEC control register. Merge the contents of cxl_hdm_decode_init() into
cxl_dvsec_ranges() and rename the combined function cxl_hdm_decode_init().
The possible cleanups and fixes that result from this merge are saved for a
follow-on change.

Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/165291690027.1426646.10249756632415633752.stgit@dwillia2-xfh
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl/mem: Consolidate CXL DVSEC Range enumeration in the core

In preparation for fixing the setting of the 'mem_enabled' bit in CXL
DVSEC Control register, move all CXL DVSEC range enumeration into the
same source file.

Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/165291688886.1426646.15046138604010482084.stgit@dwillia2-xfh
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl/pci: Retrieve CXL DVSEC memory info

Before CXL 2.0 HDM Decoder Capability mechanisms can be utilized in a
device the driver must determine that the device is ready for CXL.mem
operation and that platform firmware, or some other agent, has
established an active decode via the legacy CXL 1.1 decoder mechanism.

This legacy mechanism is defined in the CXL DVSEC as a set of range
registers and status bits that take time to settle after a reset.

Validate the CXL memory decode setup via the DVSEC and cache it for
later consideration by the cxl_mem driver (to be added). Failure to
validate is not fatal to the cxl_pci driver since that is only providing
CXL command support over PCI.mmio, and might be needed to rectify CXL
DVSEC validation problems.

Any potential ranges that the device is already claiming via DVSEC need
to be reconciled with the dynamic provisioning ranges provided by
platform firmware (like ACPI CEDT.CFMWS). Leave that reconciliation to
the cxl_mem driver.

[djbw: shorten defines]
[djbw: change precise spin wait to generous msleep]

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
[djbw: clarify changelog]
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/164375911821.559935.7375160041663453400.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl/core/port: Remove @host argument for dport + decoder enumeration

Now that dport and decoder enumeration is centralized in the port
driver, the @host argument for these helpers can be made implicit. For
the root port the host is the port's uport device (ACPI0017 for
cxl_acpi), and for all other descendant ports the devm context is the
parent of @port.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
Link: https://lore.kernel.org/r/164375043390.484143.17617734732003230076.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl/port: Add a driver for 'struct cxl_port' objects

The need for a CXL port driver and a dedicated cxl_bus_type is driven by
a need to simultaneously support 2 independent physical memory decode
domains (cache coherent CXL.mem and uncached PCI.mmio) that also
intersect at a single PCIe device node. A CXL Port is a device that
advertises a CXL Component Register block with an "HDM Decoder
Capability Structure".

>From Documentation/driver-api/cxl/memory-devices.rst:

Similar to how a RAID driver takes disk objects and assembles them into
a new logical device, the CXL subsystem is tasked to take PCIe and ACPI
objects and assemble them into a CXL.mem decode topology. The need for
runtime configuration of the CXL.mem topology is also similar to RAID in
that different environments with the same hardware configuration may
decide to assemble the topology in contrasting ways. One may choose
performance (RAID0) striping memory across multiple Host Bridges and
endpoints while another may opt for fault tolerance and disable any
striping in the CXL.mem topology.

The port driver identifies whether an endpoint Memory Expander is
connected to a CXL topology. If an active (bound to the 'cxl_port'
driver) CXL Port is not found at every PCIe Switch Upstream port and an
active "root" CXL Port then the device is just a plain PCIe endpoint
only capable of participating in PCI.mmio and DMA cycles, not CXL.mem
coherent interleave sets.

The 'cxl_port' driver lets the CXL subsystem leverage driver-core
infrastructure for setup and teardown of register resources and
communicating device activation status to userspace. The cxl_bus_type
can rendezvous the async arrival of platform level CXL resources (via
the 'cxl_acpi' driver) with the asynchronous enumeration of Memory
Expander endpoints, while also implementing a hierarchical locking model
independent of the associated 'struct pci_dev' locking model. The
locking for dport and decoder enumeration is now handled in the core
rather than callers.

For now the port driver only enumerates and registers CXL resources
(downstream port metadata and decoder resources) later it will be used
to take action on its decoders in response to CXL.mem region
provisioning requests.

Note1: cxlpci.h has long depended on pci.h, but port.c was the first to
not include pci.h. Carry that dependency in cxlpci.h.

Note2: cxl port enumeration and probing complicates CXL subsystem init
to the point that it helps to have centralized debug logging of probe
events in cxl_bus_probe().

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Co-developed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/164374948116.464348.1772618057599155408.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl/core: Generalize dport enumeration in the core

The core houses infrastructure for decoder resources. A CXL port's
dports are more closely related to decoder infrastructure than topology
enumeration. Implement generic PCI based dport enumeration in the core,
i.e. arrange for existing root port enumeration from cxl_acpi to share
code with switch port enumeration which just amounts to a small
difference in a pci_walk_bus() invocation once the appropriate 'struct
pci_bus' has been retrieved.

Set the convention that decoder objects are registered after all dports
are enumerated. This enables userspace to know when the CXL core is
finished establishing 'dportX' links underneath the 'portX' object.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/164368114191.354031.5270501846455462665.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

cxl/pci: Rename pci.h to cxlpci.h

Similar to the mem.h rename, if the core wants to reuse definitions from
drivers/cxl/pci.h it is unable to use <pci.h> as that collides with
archs that have an arch/$arch/include/asm/pci.h, like MIPS.

Reported-by: kernel test robot <lkp@intel.com>
Acked-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/164298422510.3018233.14693126572756675563.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>