Patch "PCI: qcom: Make sure PCIe is reset before init for rev 2.1.0" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    PCI: qcom: Make sure PCIe is reset before init for rev 2.1.0

to the 5.4-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-qcom-make-sure-pcie-is-reset-before-init-for-rev.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 3dab0318bccd31f394f4a3a8561d3f062e7f6dd7
Author: Ansuel Smith <ansuelsmth@xxxxxxxxx>
Date:   Tue Sep 1 14:49:54 2020 +0200

    PCI: qcom: Make sure PCIe is reset before init for rev 2.1.0
    
    [ Upstream commit d3d4d028afb785e52c55024d779089654f8302e7 ]
    
    Qsdk U-Boot can incorrectly leave the PCIe interface in an undefined
    state if bootm command is used instead of bootipq. This is caused by the
    not deinit of PCIe when bootm is called. Reset the PCIe before init
    anyway to fix this U-Boot bug.
    
    Link: https://lore.kernel.org/r/20200901124955.137-1-ansuelsmth@xxxxxxxxx
    Fixes: 82a823833f4e ("PCI: qcom: Add Qualcomm PCIe controller driver")
    Signed-off-by: Ansuel Smith <ansuelsmth@xxxxxxxxx>
    Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
    Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
    Cc: stable@xxxxxxxxxxxxxxx # v4.19+
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 374db5d59cf87..14196c0287a24 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -303,6 +303,9 @@ static void qcom_pcie_deinit_2_1_0(struct qcom_pcie *pcie)
 	clk_disable_unprepare(res->core_clk);
 	clk_disable_unprepare(res->aux_clk);
 	clk_disable_unprepare(res->ref_clk);
+
+	writel(1, pcie->parf + PCIE20_PARF_PHY_CTRL);
+
 	regulator_bulk_disable(ARRAY_SIZE(res->supplies), res->supplies);
 }
 
@@ -315,6 +318,16 @@ static int qcom_pcie_init_2_1_0(struct qcom_pcie *pcie)
 	u32 val;
 	int ret;
 
+	/* reset the PCIe interface as uboot can leave it undefined state */
+	reset_control_assert(res->pci_reset);
+	reset_control_assert(res->axi_reset);
+	reset_control_assert(res->ahb_reset);
+	reset_control_assert(res->por_reset);
+	reset_control_assert(res->ext_reset);
+	reset_control_assert(res->phy_reset);
+
+	writel(1, pcie->parf + PCIE20_PARF_PHY_CTRL);
+
 	ret = regulator_bulk_enable(ARRAY_SIZE(res->supplies), res->supplies);
 	if (ret < 0) {
 		dev_err(dev, "cannot enable regulators\n");