target/linux/bcm27xx/patches-6.1/950-0847-PCI-brcmstb-Wait-for-100ms-following-PERST-deassert.patch

   1 From 6f634d7efb8876e5953c30c0a613aaa5f575fe05 Mon Sep 17 00:00:00 2001
   2 From: Jim Quinlan <jim2101024@gmail.com>
   3 Date: Tue, 11 Oct 2022 14:42:07 -0400
   4 Subject: [PATCH] PCI: brcmstb: Wait for 100ms following PERST# deassert
   5
   6 commit 3ae140ad827b359bc4fa7c7985691c4c1e3ca8f4 upstream.
   7
   8 Be prudent and give some time for power and clocks to become stable.  As
   9 described in the PCIe CEM specification sections 2.2 and 2.2.1; as well as
  10 PCIe r5.0, 6.6.1.
  11
  12 Link: https://lore.kernel.org/r/20221011184211.18128-3-jim2101024@gmail.com
  13 Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
  14 Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
  15 Acked-by: Florian Fainelli <f.fainelli@gmail.com>
  16 ---
  17  drivers/pci/controller/pcie-brcmstb.c | 11 +++++++++--
  18  1 file changed, 9 insertions(+), 2 deletions(-)
  19
  20 --- a/drivers/pci/controller/pcie-brcmstb.c
  21 +++ b/drivers/pci/controller/pcie-brcmstb.c
  22 @@ -1038,8 +1038,15 @@ static int brcm_pcie_start_link(struct b
  23         pcie->perst_set(pcie, 0);
  24
  25         /*
  26 -        * Give the RC/EP time to wake up, before trying to configure RC.
  27 -        * Intermittently check status for link-up, up to a total of 100ms.
  28 +        * Wait for 100ms after PERST# deassertion; see PCIe CEM specification
  29 +        * sections 2.2, PCIe r5.0, 6.6.1.
  30 +        */
  31 +       msleep(100);
  32 +
  33 +       /*
  34 +        * Give the RC/EP even more time to wake up, before trying to
  35 +        * configure RC.  Intermittently check status for link-up, up to a
  36 +        * total of 100ms.
  37          */
  38         for (i = 0; i < 100 && !brcm_pcie_link_up(pcie); i += 5)
  39                 msleep(5);