[PATCH v1 2/5] PCI: brcmstb: Wait for 100ms following PERST# deassert
From: Jim Quinlan
Date: Thu Oct 06 2022 - 18:03:56 EST
Be prudent and give some time for power and clocks to become stable. As
described in the PCIe CEM specification sections 2.2 and 2.2.1; as well as
PCIe r5.0, 6.6.1.
Signed-off-by: Jim Quinlan <jim2101024@xxxxxxxxx>
drivers/pci/controller/pcie-brcmstb.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index a45ce7d61847..39b545713ba0 100644
@@ -1037,8 +1037,15 @@ static int brcm_pcie_start_link(struct brcm_pcie *pcie)
- * Give the RC/EP time to wake up, before trying to configure RC.
- * Intermittently check status for link-up, up to a total of 100ms.
+ * Wait for 100ms after PERST# deassertion; see PCIe CEM specification
+ * sections 2.2, PCIe r5.0, 6.6.1.
+ * Give the RC/EP even more time to wake up, before trying to
+ * configure RC. Intermittently check status for link-up, up to a
+ * total of 100ms.
for (i = 0; i < 100 && !brcm_pcie_link_up(pcie); i += 5)