Commit 3ae140ad authored by Jim Quinlan's avatar Jim Quinlan Committed by Lorenzo Pieralisi
Browse files

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: default avatarJim Quinlan <jim2101024@gmail.com>
Signed-off-by: default avatarLorenzo Pieralisi <lpieralisi@kernel.org>
Acked-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
parent 198acab1

drivers/pci/controller/pcie-brcmstb.c

+9 −2
Original line number Diff line number Diff line
@@ -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);