mvebu: armada-37xx: Backport PCI aardvark patches

This commit contains patches for PCI aardvark driver and relevant DTS
changes for Turris MOX and EspressoBin backported from mainline kernel.
It fixes support for old ATF, various wifi cards, mainly Compex WLE900VX.

Signed-off-by: Pali Rohár <pali@kernel.org>

1 files changed, 50 insertions, 0 deletions

diff --git a/target/linux/mvebu/patches-5.4/408-PCI-aardvark-Don-t-touch-PCIe-registers-if-no-card-c.patch b/target/linux/mvebu/patches-5.4/408-PCI-aardvark-Don-t-touch-PCIe-registers-if-no-card-c.patch
new file mode 100644
index 0000000000..9bff37b27a
--- /dev/null
+++ b/target/linux/mvebu/patches-5.4/408-PCI-aardvark-Don-t-touch-PCIe-registers-if-no-card-c.patch
@@ -0,0 +1,50 @@
+From 70e380250c3621c55ff218cbaf2272830d9dbb1d Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Pali=20Roh=C3=A1r?= <pali@kernel.org>
+Date: Thu, 2 Jul 2020 10:30:36 +0200
+Subject: [PATCH] PCI: aardvark: Don't touch PCIe registers if no card
+ connected
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+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@kernel.org
+Signed-off-by: Pali Rohár <pali@kernel.org>
+Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
+---
+ drivers/pci/controller/pci-aardvark.c | 7 +++++++
+ 1 file changed, 7 insertions(+)
+
+--- a/drivers/pci/controller/pci-aardvark.c
++++ b/drivers/pci/controller/pci-aardvark.c
+@@ -640,6 +640,13 @@ 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;
+ }
+