diff options
| author | Niklas Cassel <cassel@kernel.org> | 2025-06-25 12:23:51 +0200 |
|---|---|---|
| committer | Manivannan Sadhasivam <mani@kernel.org> | 2025-06-25 07:25:58 -0600 |
| commit | 80dc18a0cba8dea42614f021b20a04354b213d86 (patch) | |
| tree | 1a49da38a7711fa0978975f13712b8b9f47847cd /drivers/pci/controller/dwc | |
| parent | 15b6b243cc2b1017cf89e2477aa0b4e1a306a82a (diff) | |
PCI: dwc: Ensure that dw_pcie_wait_for_link() waits 100 ms after link up
As per PCIe r6.0, sec 6.6.1, a Downstream Port that supports Link speeds
greater than 5.0 GT/s, software must wait a minimum of 100 ms after Link
training completes before sending a Configuration Request.
Add this delay in dw_pcie_wait_for_link(), after the link is reported as
up. The delay will only be performed in the success case where the link
came up.
DWC glue drivers that have a link up IRQ (drivers that set
use_linkup_irq = true) do not call dw_pcie_wait_for_link(), instead they
perform this delay in their threaded link up IRQ handler.
Signed-off-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
Link: https://patch.msgid.link/20250625102347.1205584-14-cassel@kernel.org
Diffstat (limited to 'drivers/pci/controller/dwc')
| -rw-r--r-- | drivers/pci/controller/dwc/pcie-designware.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c index 4d794964fa0f..053e9c540439 100644 --- a/drivers/pci/controller/dwc/pcie-designware.c +++ b/drivers/pci/controller/dwc/pcie-designware.c @@ -714,6 +714,14 @@ int dw_pcie_wait_for_link(struct dw_pcie *pci) return -ETIMEDOUT; } + /* + * As per PCIe r6.0, sec 6.6.1, a Downstream Port that supports Link + * speeds greater than 5.0 GT/s, software must wait a minimum of 100 ms + * after Link training completes before sending a Configuration Request. + */ + if (pci->max_link_speed > 2) + msleep(PCIE_RESET_CONFIG_WAIT_MS); + offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); val = dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKSTA); |