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diff --git a/target/linux/mvebu/patches-5.4/405-PCI-aardvark-Improve-link-training.patch b/target/linux/mvebu/patches-5.4/405-PCI-aardvark-Improve-link-training.patch
new file mode 100644
index 0000000000..20723894ec
--- /dev/null
+++ b/target/linux/mvebu/patches-5.4/405-PCI-aardvark-Improve-link-training.patch
@@ -0,0 +1,208 @@
+From 43fc679ced18006b12d918d7a8a4af392b7fbfe7 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Marek=20Beh=C3=BAn?= <marek.behun@nic.cz>
+Date: Thu, 30 Apr 2020 10:06:17 +0200
+Subject: [PATCH] PCI: aardvark: Improve link training
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Currently the aardvark driver trains link in PCIe gen2 mode. This may
+cause some buggy gen1 cards (such as Compex WLE900VX) to be unstable or
+even not detected. Moreover when ASPM code tries to retrain link second
+time, these cards may stop responding and link goes down. If gen1 is
+used this does not happen.
+
+Unconditionally forcing gen1 is not a good solution since it may have
+performance impact on gen2 cards.
+
+To overcome this, read 'max-link-speed' property (as defined in PCI
+device tree bindings) and use this as max gen mode. Then iteratively try
+link training at this mode or lower until successful. After successful
+link training choose final controller gen based on Negotiated Link Speed
+from Link Status register, which should match card speed.
+
+Link: https://lore.kernel.org/r/20200430080625.26070-5-pali@kernel.org
+Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
+Signed-off-by: Pali Rohár <pali@kernel.org>
+Signed-off-by: Marek Behún <marek.behun@nic.cz>
+Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
+Reviewed-by: Rob Herring <robh@kernel.org>
+Acked-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
+---
+ drivers/pci/controller/pci-aardvark.c | 114 ++++++++++++++++++++------
+ 1 file changed, 89 insertions(+), 25 deletions(-)
+
+--- a/drivers/pci/controller/pci-aardvark.c
++++ b/drivers/pci/controller/pci-aardvark.c
+@@ -39,6 +39,7 @@
+ #define PCIE_CORE_LINK_CTRL_STAT_REG 0xd0
+ #define PCIE_CORE_LINK_L0S_ENTRY BIT(0)
+ #define PCIE_CORE_LINK_TRAINING BIT(5)
++#define PCIE_CORE_LINK_SPEED_SHIFT 16
+ #define PCIE_CORE_LINK_WIDTH_SHIFT 20
+ #define PCIE_CORE_ERR_CAPCTL_REG 0x118
+ #define PCIE_CORE_ERR_CAPCTL_ECRC_CHK_TX BIT(5)
+@@ -201,6 +202,7 @@ struct advk_pcie {
+ struct mutex msi_used_lock;
+ u16 msi_msg;
+ int root_bus_nr;
++ int link_gen;
+ struct pci_bridge_emul bridge;
+ };
+
+@@ -225,20 +227,16 @@ static int advk_pcie_link_up(struct advk
+
+ static int advk_pcie_wait_for_link(struct advk_pcie *pcie)
+ {
+- struct device *dev = &pcie->pdev->dev;
+ int retries;
+
+ /* check if the link is up or not */
+ for (retries = 0; retries < LINK_WAIT_MAX_RETRIES; retries++) {
+- if (advk_pcie_link_up(pcie)) {
+- dev_info(dev, "link up\n");
++ if (advk_pcie_link_up(pcie))
+ return 0;
+- }
+
+ usleep_range(LINK_WAIT_USLEEP_MIN, LINK_WAIT_USLEEP_MAX);
+ }
+
+- dev_err(dev, "link never came up\n");
+ return -ETIMEDOUT;
+ }
+
+@@ -253,6 +251,85 @@ static void advk_pcie_wait_for_retrain(s
+ }
+ }
+
++static int advk_pcie_train_at_gen(struct advk_pcie *pcie, int gen)
++{
++ int ret, neg_gen;
++ u32 reg;
++
++ /* Setup link speed */
++ reg = advk_readl(pcie, PCIE_CORE_CTRL0_REG);
++ reg &= ~PCIE_GEN_SEL_MSK;
++ if (gen == 3)
++ reg |= SPEED_GEN_3;
++ else if (gen == 2)
++ reg |= SPEED_GEN_2;
++ else
++ reg |= SPEED_GEN_1;
++ advk_writel(pcie, reg, PCIE_CORE_CTRL0_REG);
++
++ /*
++ * Enable link training. This is not needed in every call to this
++ * function, just once suffices, but it does not break anything either.
++ */
++ reg = advk_readl(pcie, PCIE_CORE_CTRL0_REG);
++ reg |= LINK_TRAINING_EN;
++ advk_writel(pcie, reg, PCIE_CORE_CTRL0_REG);
++
++ /*
++ * Start link training immediately after enabling it.
++ * This solves problems for some buggy cards.
++ */
++ reg = advk_readl(pcie, PCIE_CORE_LINK_CTRL_STAT_REG);
++ reg |= PCIE_CORE_LINK_TRAINING;
++ advk_writel(pcie, reg, PCIE_CORE_LINK_CTRL_STAT_REG);
++
++ ret = advk_pcie_wait_for_link(pcie);
++ if (ret)
++ return ret;
++
++ reg = advk_readl(pcie, PCIE_CORE_LINK_CTRL_STAT_REG);
++ neg_gen = (reg >> PCIE_CORE_LINK_SPEED_SHIFT) & 0xf;
++
++ return neg_gen;
++}
++
++static void advk_pcie_train_link(struct advk_pcie *pcie)
++{
++ struct device *dev = &pcie->pdev->dev;
++ int neg_gen = -1, gen;
++
++ /*
++ * Try link training at link gen specified by device tree property
++ * 'max-link-speed'. If this fails, iteratively train at lower gen.
++ */
++ for (gen = pcie->link_gen; gen > 0; --gen) {
++ neg_gen = advk_pcie_train_at_gen(pcie, gen);
++ if (neg_gen > 0)
++ break;
++ }
++
++ if (neg_gen < 0)
++ goto err;
++
++ /*
++ * After successful training if negotiated gen is lower than requested,
++ * train again on negotiated gen. This solves some stability issues for
++ * some buggy gen1 cards.
++ */
++ if (neg_gen < gen) {
++ gen = neg_gen;
++ neg_gen = advk_pcie_train_at_gen(pcie, gen);
++ }
++
++ if (neg_gen == gen) {
++ dev_info(dev, "link up at gen %i\n", gen);
++ return;
++ }
++
++err:
++ dev_err(dev, "link never came up\n");
++}
++
+ static void advk_pcie_setup_hw(struct advk_pcie *pcie)
+ {
+ u32 reg;
+@@ -288,12 +365,6 @@ static void advk_pcie_setup_hw(struct ad
+ PCIE_CORE_CTRL2_TD_ENABLE;
+ advk_writel(pcie, reg, PCIE_CORE_CTRL2_REG);
+
+- /* Set GEN2 */
+- reg = advk_readl(pcie, PCIE_CORE_CTRL0_REG);
+- reg &= ~PCIE_GEN_SEL_MSK;
+- reg |= SPEED_GEN_2;
+- advk_writel(pcie, reg, PCIE_CORE_CTRL0_REG);
+-
+ /* Set lane X1 */
+ reg = advk_readl(pcie, PCIE_CORE_CTRL0_REG);
+ reg &= ~LANE_CNT_MSK;
+@@ -341,20 +412,7 @@ static void advk_pcie_setup_hw(struct ad
+ */
+ msleep(PCI_PM_D3COLD_WAIT);
+
+- /* Enable link training */
+- reg = advk_readl(pcie, PCIE_CORE_CTRL0_REG);
+- reg |= LINK_TRAINING_EN;
+- advk_writel(pcie, reg, PCIE_CORE_CTRL0_REG);
+-
+- /*
+- * Start link training immediately after enabling it.
+- * This solves problems for some buggy cards.
+- */
+- reg = advk_readl(pcie, PCIE_CORE_LINK_CTRL_STAT_REG);
+- reg |= PCIE_CORE_LINK_TRAINING;
+- advk_writel(pcie, reg, PCIE_CORE_LINK_CTRL_STAT_REG);
+-
+- advk_pcie_wait_for_link(pcie);
++ advk_pcie_train_link(pcie);
+
+ reg = advk_readl(pcie, PCIE_CORE_CMD_STATUS_REG);
+ reg |= PCIE_CORE_CMD_MEM_ACCESS_EN |
+@@ -1036,6 +1094,12 @@ static int advk_pcie_probe(struct platfo
+ return ret;
+ }
+
++ ret = of_pci_get_max_link_speed(dev->of_node);
++ if (ret <= 0 || ret > 3)
++ pcie->link_gen = 3;
++ else
++ pcie->link_gen = ret;
++
+ advk_pcie_setup_hw(pcie);
+
+ advk_sw_pci_bridge_init(pcie);