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In Restricted CXL Device (RCD) mode a CXL device is exposed as an RCiEP, but CXL downstream and upstream ports are not enumerated and not visible in the PCIe hierarchy. [1] Protocol and link errors from these non-enumerated ports are signaled as internal AER errors, either Uncorrectable Internal Error (UIE) or Corrected Internal Errors (CIE) via an RCEC. Restricted CXL host (RCH) downstream port-detected errors have the Requester ID of the RCEC set in the RCEC's AER Error Source ID register. A CXL handler must then inspect the error status in various CXL registers residing in the dport's component register space (CXL RAS capability) or the dport's RCRB (PCIe AER extended capability). [2] Errors showing up in the RCEC's error handler must be handled and connected to the CXL subsystem. Implement this by forwarding the error to all CXL devices below the RCEC. Since the entire CXL device is controlled only using PCIe Configuration Space of device 0, function 0, only pass it there [3]. The error handling is limited to currently supported devices with the Memory Device class code set (CXL Type 3 Device, PCI_CLASS_MEMORY_CXL, 502h), handle downstream port errors in the device's cxl_pci driver. Support for other CXL Device Types (e.g. a CXL.cache Device) can be added later. To handle downstream port errors in addition to errors directed to the CXL endpoint device, a handler must also inspect the CXL RAS and PCIe AER capabilities of the CXL downstream port the device is connected to. Since CXL downstream port errors are signaled using internal errors, the handler requires those errors to be unmasked. This is subject of a follow-on patch. The reason for choosing this implementation is that the AER service driver claims the RCEC device, but does not allow it to register a custom specific handler to support CXL. Connecting the RCEC hard-wired with a CXL handler does not work, as the CXL subsystem might not be present all the time. The alternative to add an implementation to the portdrv to allow the registration of a custom RCEC error handler isn't worth doing it as CXL would be its only user. Instead, just check for an CXL RCEC and pass it down to the connected CXL device's error handler. With this approach the code can entirely be implemented in the PCIe AER driver and is independent of the CXL subsystem. The CXL driver only provides the handler. [1] CXL 3.0 spec: 9.11.8 CXL Devices Attached to an RCH [2] CXL 3.0 spec, 12.2.1.1 RCH Downstream Port-detected Errors [3] CXL 3.0 spec, 8.1.3 PCIe DVSEC for CXL Devices Co-developed-by: Terry Bowman <terry.bowman@amd.com> Signed-off-by: Terry Bowman <terry.bowman@amd.com> Signed-off-by: Robert Richter <rrichter@amd.com> Cc: Oliver O'Halloran <oohall@gmail.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-pci@vger.kernel.org Acked-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/20231018171713.1883517-18-rrichter@amd.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
158 lines
4.3 KiB
Plaintext
158 lines
4.3 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0
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#
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# PCI Express Port Bus Configuration
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#
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config PCIEPORTBUS
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bool "PCI Express Port Bus support"
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default y if USB4
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help
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This enables PCI Express Port Bus support. Users can then enable
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support for Native Hot-Plug, Advanced Error Reporting, Power
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Management Events, and Downstream Port Containment.
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#
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# Include service Kconfig here
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#
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config HOTPLUG_PCI_PCIE
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bool "PCI Express Hotplug driver"
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depends on HOTPLUG_PCI && PCIEPORTBUS
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default y if USB4
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help
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Say Y here if you have a motherboard that supports PCIe native
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hotplug.
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Thunderbolt/USB4 PCIe tunneling depends on native PCIe hotplug.
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When in doubt, say N.
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config PCIEAER
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bool "PCI Express Advanced Error Reporting support"
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depends on PCIEPORTBUS
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select RAS
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help
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This enables PCI Express Root Port Advanced Error Reporting
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(AER) driver support. Error reporting messages sent to Root
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Port will be handled by PCI Express AER driver.
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config PCIEAER_INJECT
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tristate "PCI Express error injection support"
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depends on PCIEAER
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select GENERIC_IRQ_INJECTION
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help
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This enables PCI Express Root Port Advanced Error Reporting
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(AER) software error injector.
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Debugging AER code is quite difficult because it is hard
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to trigger various real hardware errors. Software-based
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error injection can fake almost all kinds of errors with the
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help of a user space helper tool aer-inject, which can be
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gotten from:
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https://git.kernel.org/cgit/linux/kernel/git/gong.chen/aer-inject.git/
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config PCIEAER_CXL
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bool "PCI Express CXL RAS support"
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default y
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depends on PCIEAER && CXL_PCI
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help
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Enables CXL error handling.
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If unsure, say Y.
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#
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# PCI Express ECRC
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#
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config PCIE_ECRC
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bool "PCI Express ECRC settings control"
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depends on PCIEAER
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help
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Used to override firmware/bios settings for PCI Express ECRC
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(transaction layer end-to-end CRC checking).
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When in doubt, say N.
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#
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# PCI Express ASPM
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#
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config PCIEASPM
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bool "PCI Express ASPM control" if EXPERT
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default y
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help
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This enables OS control over PCI Express ASPM (Active State
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Power Management) and Clock Power Management. ASPM supports
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state L0/L0s/L1.
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ASPM is initially set up by the firmware. With this option enabled,
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Linux can modify this state in order to disable ASPM on known-bad
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hardware or configurations and enable it when known-safe.
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ASPM can be disabled or enabled at runtime via
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/sys/module/pcie_aspm/parameters/policy
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When in doubt, say Y.
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choice
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prompt "Default ASPM policy"
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default PCIEASPM_DEFAULT
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depends on PCIEASPM
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config PCIEASPM_DEFAULT
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bool "BIOS default"
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depends on PCIEASPM
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help
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Use the BIOS defaults for PCI Express ASPM.
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config PCIEASPM_POWERSAVE
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bool "Powersave"
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depends on PCIEASPM
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help
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Enable PCI Express ASPM L0s and L1 where possible, even if the
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BIOS did not.
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config PCIEASPM_POWER_SUPERSAVE
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bool "Power Supersave"
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depends on PCIEASPM
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help
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Same as PCIEASPM_POWERSAVE, except it also enables L1 substates where
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possible. This would result in higher power savings while staying in L1
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where the components support it.
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config PCIEASPM_PERFORMANCE
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bool "Performance"
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depends on PCIEASPM
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help
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Disable PCI Express ASPM L0s and L1, even if the BIOS enabled them.
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endchoice
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config PCIE_PME
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def_bool y
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depends on PCIEPORTBUS && PM
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config PCIE_DPC
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bool "PCI Express Downstream Port Containment support"
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depends on PCIEPORTBUS && PCIEAER
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help
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This enables PCI Express Downstream Port Containment (DPC)
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driver support. DPC events from Root and Downstream ports
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will be handled by the DPC driver. If your system doesn't
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have this capability or you do not want to use this feature,
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it is safe to answer N.
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config PCIE_PTM
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bool "PCI Express Precision Time Measurement support"
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help
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This enables PCI Express Precision Time Measurement (PTM)
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support.
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This is only useful if you have devices that support PTM, but it
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is safe to enable even if you don't.
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config PCIE_EDR
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bool "PCI Express Error Disconnect Recover support"
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depends on PCIE_DPC && ACPI
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help
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This option adds Error Disconnect Recover support as specified
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in the Downstream Port Containment Related Enhancements ECN to
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the PCI Firmware Specification r3.2. Enable this if you want to
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support hybrid DPC model which uses both firmware and OS to
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implement DPC.
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