diff options
| author | Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> | 2024-04-30 11:43:49 +0530 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2024-07-09 18:20:18 -0500 |
| commit | 867ab111b2420ca97e9156ad1e186d2face5c62c (patch) | |
| tree | afb0636e686de33a297fd04baea3fbe72ee0e542 /drivers/pci/controller/dwc/pcie-designware.h | |
| parent | e1a4ec1a9520bf048a7ee09f7f7a82b1d44750ac (diff) | |
PCI: dwc: ep: Add a generic dw_pcie_ep_linkdown() API to handle Link Down event
Per PCIe r6.0, sec 5.2, a Link Down event can happen under any of the
following circumstances:
1. Fundamental/Hot reset
2. Link disable transmission by upstream component
3. Moving from L2/L3 to L0
In those cases, Link Down causes some non-sticky DWC registers to lose the
state (like REBAR, etc.), so drivers need to reinitialize them to function
properly once the link comes back again.
This is not a problem for drivers supporting PERST# IRQ, since they can
reinitialize the registers in the PERST# IRQ callback. But for the drivers
not supporting PERST#, there is no way they can reinitialize the registers
other than relying on Link Down IRQ received when the link goes down. So
add a DWC generic API dw_pcie_ep_linkdown() that reinitializes the
non-sticky registers and also notifies the EPF drivers about link going
down.
This API can also be used by the drivers supporting PERST# to handle the
scenario (2) mentioned above.
NOTE: For the sake of code organization, move the dw_pcie_ep_linkup()
definition just above dw_pcie_ep_linkdown().
Link: https://lore.kernel.org/linux-pci/20240430-pci-epf-rework-v4-8-22832d0d456f@linaro.org
Tested-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
[bhelgaas: update spec citation]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Diffstat (limited to 'drivers/pci/controller/dwc/pcie-designware.h')
| -rw-r--r-- | drivers/pci/controller/dwc/pcie-designware.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h index 39ec253df6cf..5822eb09ead7 100644 --- a/drivers/pci/controller/dwc/pcie-designware.h +++ b/drivers/pci/controller/dwc/pcie-designware.h @@ -681,6 +681,7 @@ static inline void __iomem *dw_pcie_own_conf_map_bus(struct pci_bus *bus, #ifdef CONFIG_PCIE_DW_EP void dw_pcie_ep_linkup(struct dw_pcie_ep *ep); +void dw_pcie_ep_linkdown(struct dw_pcie_ep *ep); int dw_pcie_ep_init(struct dw_pcie_ep *ep); int dw_pcie_ep_init_registers(struct dw_pcie_ep *ep); void dw_pcie_ep_init_notify(struct dw_pcie_ep *ep); @@ -701,6 +702,10 @@ static inline void dw_pcie_ep_linkup(struct dw_pcie_ep *ep) { } +static inline void dw_pcie_ep_linkdown(struct dw_pcie_ep *ep) +{ +} + static inline int dw_pcie_ep_init(struct dw_pcie_ep *ep) { return 0; |