diff options
| author | Jim Quinlan <jim2101024@gmail.com> | 2022-10-11 14:42:07 -0400 |
|---|---|---|
| committer | Lorenzo Pieralisi <lpieralisi@kernel.org> | 2022-11-11 11:40:47 +0100 |
| commit | 3ae140ad827b359bc4fa7c7985691c4c1e3ca8f4 (patch) | |
| tree | d73bc4e3b583fff917e58e1516fa088f627662a5 | |
| parent | 198acab1772f22f2e91f68a2fc1331e91dad780a (diff) | |
| download | lwn-3ae140ad827b359bc4fa7c7985691c4c1e3ca8f4.tar.gz lwn-3ae140ad827b359bc4fa7c7985691c4c1e3ca8f4.zip | |
PCI: brcmstb: Wait for 100ms following PERST# deassert
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.
Link: https://lore.kernel.org/r/20221011184211.18128-3-jim2101024@gmail.com
Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
| -rw-r--r-- | drivers/pci/controller/pcie-brcmstb.c | 11 |
1 files 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 --- a/drivers/pci/controller/pcie-brcmstb.c +++ b/drivers/pci/controller/pcie-brcmstb.c @@ -1037,8 +1037,15 @@ static int brcm_pcie_start_link(struct brcm_pcie *pcie) pcie->perst_set(pcie, 0); /* - * 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. + */ + msleep(100); + + /* + * 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) msleep(5); |