The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 6df19872d881641e6394f93ef2938cffcbdae5bb Mon Sep 17 00:00:00 2001

From: Yurii Monakov monakov.y@gmail.com Date: Tue, 17 Dec 2019 14:38:36 +0300 Subject: [PATCH] PCI: keystone: Fix link training retries initiation

ks_pcie_stop_link() function does not clear LTSSM_EN_VAL bit so link training was not triggered more than once after startup. In configurations where link can be unstable during early boot, for example, under low temperature, it will never be established.

Fixes: 0c4ffcfe1fbc ("PCI: keystone: Add TI Keystone PCIe driver") Signed-off-by: Yurii Monakov monakov.y@gmail.com Signed-off-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Acked-by: Andrew Murray andrew.murray@arm.com Cc: stable@vger.kernel.org

diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c index af677254a072..d4de4f6cff8b 100644 --- a/drivers/pci/controller/dwc/pci-keystone.c +++ b/drivers/pci/controller/dwc/pci-keystone.c @@ -510,7 +510,7 @@ static void ks_pcie_stop_link(struct dw_pcie *pci) /* Disable Link training */ val = ks_pcie_app_readl(ks_pcie, CMD_STATUS); val &= ~LTSSM_EN_VAL; - ks_pcie_app_writel(ks_pcie, CMD_STATUS, LTSSM_EN_VAL | val); + ks_pcie_app_writel(ks_pcie, CMD_STATUS, val); }

static int ks_pcie_start_link(struct dw_pcie *pci)