diff options
| author | Bjorn Helgaas <bhelgaas@google.com> | 2025-11-18 15:42:15 -0600 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2025-11-24 16:47:19 -0600 |
| commit | a00bba406b5a682764ecb507e580ca8159196aa3 (patch) | |
| tree | 140904fe04b43df978217e6899e9ddb5f73c0336 /drivers/pci/controller/dwc/pcie-designware.h | |
| parent | bcc9a4a0bca3aee4303fa4a20302e57b24ac8f68 (diff) | |
PCI: dwc: Advertise L1 PM Substates only if driver requests it
L1 PM Substates require the CLKREQ# signal and may also require
device-specific support. If CLKREQ# is not supported or driver support is
lacking, enabling L1.1 or L1.2 may cause errors when accessing devices,
e.g.,
nvme nvme0: controller is down; will reset: CSTS=0xffffffff, PCI_STATUS=0x10
If the kernel is built with CONFIG_PCIEASPM_POWER_SUPERSAVE=y or users
enable L1.x via sysfs, users may trip over these errors even if L1
Substates haven't been enabled by firmware or the driver.
To prevent such errors, disable advertising the L1 PM Substates unless the
driver sets "dw_pcie.l1ss_support" to indicate that it knows CLKREQ# is
present and any device-specific configuration has been done.
Set "dw_pcie.l1ss_support" in tegra194 (if DT includes the
"supports-clkreq' property) and qcom (for cfg_2_7_0, cfg_1_9_0, cfg_1_34_0,
and cfg_sc8280xp controllers) so they can continue to use L1 Substates.
Based on Niklas's patch:
https://patch.msgid.link/20251017163252.598812-2-cassel@kernel.org
[bhelgaas: drop hiding for endpoints]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20251118214312.2598220-2-helgaas@kernel.org
Diffstat (limited to 'drivers/pci/controller/dwc/pcie-designware.h')
| -rw-r--r-- | drivers/pci/controller/dwc/pcie-designware.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h index 24bfa5231923..d3dc0cd8e7b5 100644 --- a/drivers/pci/controller/dwc/pcie-designware.h +++ b/drivers/pci/controller/dwc/pcie-designware.h @@ -516,6 +516,7 @@ struct dw_pcie { int max_link_speed; u8 n_fts[2]; struct dw_edma_chip edma; + bool l1ss_support; /* L1 PM Substates support */ struct clk_bulk_data app_clks[DW_PCIE_NUM_APP_CLKS]; struct clk_bulk_data core_clks[DW_PCIE_NUM_CORE_CLKS]; struct reset_control_bulk_data app_rsts[DW_PCIE_NUM_APP_RSTS]; @@ -573,6 +574,7 @@ int dw_pcie_prog_ep_inbound_atu(struct dw_pcie *pci, u8 func_no, int index, int type, u64 parent_bus_addr, u8 bar, size_t size); void dw_pcie_disable_atu(struct dw_pcie *pci, u32 dir, int index); +void dw_pcie_hide_unsupported_l1ss(struct dw_pcie *pci); void dw_pcie_setup(struct dw_pcie *pci); void dw_pcie_iatu_detect(struct dw_pcie *pci); int dw_pcie_edma_detect(struct dw_pcie *pci); |