This is a note to let you know that I've just added the patch titled
PCI: aardvark: Don't touch PCIe registers if no card connected
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-don-t-touch-pcie-registers-if-no-card-connected.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 23:49:19 +0100
Subject: PCI: aardvark: Don't touch PCIe registers if no card connected
To: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>, Sasha Levin <sashal@xxxxxxxxxx>
Cc: pali@xxxxxxxxxx, stable@xxxxxxxxxxxxxxx, "Lorenzo Pieralisi" <lorenzo.pieralisi@xxxxxxx>, "Marek Behún" <kabel@xxxxxxxxxx>
Message-ID: <20211124224933.24275-11-kabel@xxxxxxxxxx>
From: Pali Rohár <pali@xxxxxxxxxx>
commit 70e380250c3621c55ff218cbaf2272830d9dbb1d upstream.
When there is no PCIe card connected and advk_pcie_rd_conf() or
advk_pcie_wr_conf() is called for PCI bus which doesn't belong to emulated
root bridge, the aardvark driver throws the following error message:
advk-pcie d0070000.pcie: config read/write timed out
Obviously accessing PCIe registers of disconnected card is not possible.
Extend check in advk_pcie_valid_device() function for validating
availability of PCIe bus. If PCIe link is down, then the device is marked
as Not Found and the driver does not try to access these registers.
This is just an optimization to prevent accessing PCIe registers when card
is disconnected. Trying to access PCIe registers of disconnected card does
not cause any crash, kernel just needs to wait for a timeout. So if card
disappear immediately after checking for PCIe link (before accessing PCIe
registers), it does not cause any problems.
Link: https://lore.kernel.org/r/20200702083036.12230-1-pali@xxxxxxxxxx
Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Signed-off-by: Marek Behún <kabel@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/pci/host/pci-aardvark.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/drivers/pci/host/pci-aardvark.c
+++ b/drivers/pci/host/pci-aardvark.c
@@ -598,6 +598,13 @@ static bool advk_pcie_valid_device(struc
if ((bus->number == pcie->root_bus_nr) && PCI_SLOT(devfn) != 0)
return false;
+ /*
+ * If the link goes down after we check for link-up, nothing bad
+ * happens but the config access times out.
+ */
+ if (bus->number != pcie->root_bus_nr && !advk_pcie_link_up(pcie))
+ return false;
+
return true;
}
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
