FROMLIST: PCI: Add support for PCIe WAKE# interrupt#788
Conversation
ziyuezhang-123
requested review from
a team,
knaveen-qc,
Nicolas Dechesne (ndechesne) and
Shiraz Hashim (shashim-quic)
|
Merge Check Failed: No CR Numbers Found Error: No Change Request numbers were found. Please add Change Request numbers to your pull request description in the format CRs-Fixed: 12345 or link GitHub issues that are associated with Change Requests. |
According to the PCI Express specification (PCIe r7.0, Section 5.3.3.2), two link wakeup mechanisms are defined: Beacon and WAKE#. Beacon is a hardware-only mechanism and is invisible to software (PCIe r7.0, Section 4.2.7.8.1). This change adds support for the WAKE# mechanism in the PCI core. According to the PCIe specification, multiple WAKE# signals can exist in a system or each component in the hierarchy could share a single WAKE# signal. In configurations involving a PCIe switch, each downstream port (DSP) of the switch may be connected to a separate WAKE# line, allowing each endpoint to signal WAKE# independently. From figure 5.4 in sec 5.3.3.2, WAKE# can also be terminated at the switch itself. Such topologies are typically not described in Device Tree, therefore it is out of scope for this series. To support this, the WAKE# should be described in the device tree node of the endpoint/bridge. If all endpoints share a single WAKE# line, then each endpoint node shall describe the same WAKE# signal or a single WAKE# in the Root Port node. In pci_device_add(), PCI framework will search for the WAKE# in device node. Once found, register for the wake IRQ through dev_pm_set_dedicated_wake_irq() associates a wakeup IRQ with a device and requests it, but the PM core keeps the IRQ disabled by default. The IRQ is enabled by the PM core, only when the device is permitted to wake the system, i.e. during system suspend and after runtime suspend, and only when device wakeup is enabled. If the same WAKE# GPIO is described in multiple device tree nodes, only the first device that successfully registers the wake IRQ will succeed, while subsequent registrations may fail. This limitation does not affect functional correctness, since WAKE# is only used to bring the link to D0, and endpoint-specific wakeup handling is resolved later through PME detection (PME_EN is set in suspend path by PCI core by default). When the wake IRQ fires, the wakeirq handler invokes pm_runtime_resume() to bring the device back to an active power state, such as transitioning from D3cold to D0. Once the device is active and the link is usable, the endpoint may generate a PME, which is then handled by the PCI core through PME polling or the PCIe PME service driver to complete the wakeup of the endpoint. WAKE# is added in dts schema and merged based on below links. Link: https://lore.kernel.org/all/20250515090517.3506772-1-krishna.chundru@oss.qualcomm.com/ Link: devicetree-org/dt-schema#170 Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Manivannan Sadhasivam <mani@kernel.org> Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com> Link: https://lore.kernel.org/all/20260624-wakeirq_support-v11-1-120fbfaebe59@oss.qualcomm.com/ Signed-off-by: Ziyue Zhang <ziyue.zhang@oss.qualcomm.com>
ziyuezhang-123
force-pushed
the
for-6.18/pci-add-support-for-pcie-wake-interrupt
branch
from
0b83255 to
818a439
Compare
|
Merge Check Failed: CR Not Eligible for Merge CR 4542930 is not eligible for merge. The parent software image for kernel.qli.2.0 is not development complete. Entity: Please ensure the CR passes both CCT (ComponentChangeTasks) and ICT (Integration Change Tasks) validations. |
1 similar comment
|
Merge Check Failed: CR Not Eligible for Merge CR 4542930 is not eligible for merge. The parent software image for kernel.qli.2.0 is not development complete. Entity: Please ensure the CR passes both CCT (ComponentChangeTasks) and ICT (Integration Change Tasks) validations. |
PR #788 — validate-patchPR: #788
Final Summary
|
PR #788 — checker-log-analyzerPR: #788
Detailed report: Full report
|
3 participants
According to the PCI Express specification (PCIe r7.0, Section 5.3.3.2),
two link wakeup mechanisms are defined: Beacon and WAKE#. Beacon is a
hardware-only mechanism and is invisible to software (PCIe r7.0,
Section 4.2.7.8.1). This change adds support for the WAKE# mechanism
in the PCI core.
According to the PCIe specification, multiple WAKE# signals can exist in
a system or each component in the hierarchy could share a single WAKE#
signal. In configurations involving a PCIe switch, each downstream port
(DSP) of the switch may be connected to a separate WAKE# line, allowing
each endpoint to signal WAKE# independently. From figure 5.4 in sec
5.3.3.2, WAKE# can also be terminated at the switch itself. Such topologies
are typically not described in Device Tree, therefore it is out of scope
for this series.
To support this, the WAKE# should be described in the device tree node of
the endpoint/bridge. If all endpoints share a single WAKE# line, then each
endpoint node shall describe the same WAKE# signal or a single WAKE# in
the Root Port node.
In pci_device_add(), PCI framework will search for the WAKE# in device
node. Once found, register for the wake IRQ through
dev_pm_set_dedicated_wake_irq() associates a wakeup IRQ with a device
and requests it, but the PM core keeps the IRQ disabled by default. The
IRQ is enabled by the PM core, only when the device is permitted to wake
the system, i.e. during system suspend and after runtime suspend, and
only when device wakeup is enabled.
If the same WAKE# GPIO is described in multiple device tree nodes, only the
first device that successfully registers the wake IRQ will succeed, while
subsequent registrations may fail. This limitation does not affect
functional correctness, since WAKE# is only used to bring the link to D0,
and endpoint-specific wakeup handling is resolved later through
PME detection (PME_EN is set in suspend path by PCI core by default).
When the wake IRQ fires, the wakeirq handler invokes pm_runtime_resume() to
bring the device back to an active power state, such as transitioning from
D3cold to D0. Once the device is active and the link is usable, the
endpoint may generate a PME, which is then handled by the PCI core through
PME polling or the PCIe PME service driver to complete the wakeup of the
endpoint.
WAKE# is added in dts schema and merged based on below links.
Link: https://lore.kernel.org/all/20250515090517.3506772-1-krishna.chundru@oss.qualcomm.com/
Link: devicetree-org/dt-schema#170
Reviewed-by: Linus Walleij linus.walleij@linaro.org
Acked-by: Manivannan Sadhasivam mani@kernel.org
Signed-off-by: Krishna Chaitanya Chundru krishna.chundru@oss.qualcomm.com
Signed-off-by: Ziyue Zhang ziyue.zhang@oss.qualcomm.com
Link: https://lore.kernel.org/all/20260624-wakeirq_support-v11-1-120fbfaebe59@oss.qualcomm.com/
CRs-Fixed: 4542930