This is a note to let you know that I've just added the patch titled
PCI: aardvark: Wait for endpoint to be ready before training link
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pci-aardvark-wait-for-endpoint-to-be-ready-before-training-link.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Mon Nov 29 01:32:04 PM CET 2021
From: "Marek Behún" <kabel@xxxxxxxxxx>
Date: Wed, 24 Nov 2021 23:49:12 +0100
Subject: PCI: aardvark: Wait for endpoint to be ready before training link
To: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>, Sasha Levin <sashal@xxxxxxxxxx>
Cc: pali@xxxxxxxxxx, stable@xxxxxxxxxxxxxxx, "Remi Pommarel" <repk@xxxxxxxxxxxx>, "Lorenzo Pieralisi" <lorenzo.pieralisi@xxxxxxx>, "Thomas Petazzoni" <thomas.petazzoni@xxxxxxxxxxx>, "Marek Behún" <kabel@xxxxxxxxxx>
Message-ID: <20211124224933.24275-4-kabel@xxxxxxxxxx>
From: Remi Pommarel <repk@xxxxxxxxxxxx>
commit f4c7d053d7f77cd5c1a1ba7c7ce085ddba13d1d7 upstream.
When configuring pcie reset pin from gpio (e.g. initially set by
u-boot) to pcie function this pin goes low for a brief moment
asserting the PERST# signal. Thus connected device enters fundamental
reset process and link configuration can only begin after a minimal
100ms delay (see [1]).
Because the pin configuration comes from the "default" pinctrl it is
implicitly configured before the probe callback is called:
driver_probe_device()
really_probe()
...
pinctrl_bind_pins() /* Here pin goes from gpio to PCIE reset
function and PERST# is asserted */
...
drv->probe()
[1] "PCI Express Base Specification", REV. 4.0
PCI Express, February 19 2014, 6.6.1 Conventional Reset
Signed-off-by: Remi Pommarel <repk@xxxxxxxxxxxx>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Acked-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxx>
Signed-off-by: Marek Behún <kabel@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/pci/host/pci-aardvark.c | 8 ++++++++
1 file changed, 8 insertions(+)
--- a/drivers/pci/host/pci-aardvark.c
+++ b/drivers/pci/host/pci-aardvark.c
@@ -362,6 +362,14 @@ static void advk_pcie_setup_hw(struct ad
reg |= PIO_CTRL_ADDR_WIN_DISABLE;
advk_writel(pcie, reg, PIO_CTRL);
+ /*
+ * PERST# signal could have been asserted by pinctrl subsystem before
+ * probe() callback has been called, making the endpoint going into
+ * fundamental reset. As required by PCI Express spec a delay for at
+ * least 100ms after such a reset before link training is needed.
+ */
+ msleep(PCI_PM_D3COLD_WAIT);
+
/* Start link training */
reg = advk_readl(pcie, PCIE_CORE_LINK_CTRL_STAT_REG);
reg |= PCIE_CORE_LINK_TRAINING;
Patches currently in stable-queue which might be from kabel@xxxxxxxxxx are
queue-4.14/pci-aardvark-move-pcie-reset-card-code-to-advk_pcie_train_link.patch
queue-4.14/pci-aardvark-introduce-an-advk_pcie_valid_device-helper.patch
queue-4.14/pci-aardvark-update-comment-about-disabling-link-training.patch
queue-4.14/pci-aardvark-train-link-immediately-after-enabling-training.patch
queue-4.14/arm64-dts-marvell-armada-37xx-declare-pcie-reset-pin.patch
queue-4.14/pci-aardvark-replace-custom-macros-by-standard-linux-pci_regs.h-macros.patch
queue-4.14/pci-aardvark-fix-a-leaked-reference-by-adding-missing-of_node_put.patch
queue-4.14/pci-aardvark-fix-pcie-max-payload-size-setting.patch
queue-4.14/pinctrl-armada-37xx-correct-pwm-pins-definitions.patch
queue-4.14/arm64-dts-marvell-armada-37xx-set-pcie_reset_pin-to-gpio-function.patch
queue-4.14/pci-aardvark-configure-pcie-resources-from-ranges-dt-property.patch
queue-4.14/pci-aardvark-improve-link-training.patch
queue-4.14/pci-aardvark-fix-link-training.patch
queue-4.14/pci-aardvark-fix-checking-for-link-up-via-ltssm-state.patch
queue-4.14/pci-aardvark-issue-perst-via-gpio.patch
queue-4.14/pinctrl-armada-37xx-correct-mpp-definitions.patch
queue-4.14/pci-add-pci_exp_lnkctl2_tls-macros.patch
queue-4.14/pci-aardvark-wait-for-endpoint-to-be-ready-before-training-link.patch
queue-4.14/pinctrl-armada-37xx-add-missing-pin-pcie1-wakeup.patch
queue-4.14/pci-aardvark-fix-compilation-on-s390.patch
queue-4.14/pci-aardvark-fix-i-o-space-page-leak.patch
queue-4.14/pci-aardvark-don-t-touch-pcie-registers-if-no-card-connected.patch
queue-4.14/pci-aardvark-remove-pcie-outbound-window-configuration.patch
queue-4.14/pci-aardvark-indicate-error-in-val-when-config-read-fails.patch
