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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Ansuel Smith <ansuelsmth@gmail.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>
Subject: [PATCH 5.9 332/391] PCI: qcom: Make sure PCIe is reset before init for rev 2.1.0
Date:   Tue,  3 Nov 2020 21:36:23 +0100
Message-Id: <20201103203409.524526180@linuxfoundation.org>
In-Reply-To: <20201103203348.153465465@linuxfoundation.org>
References: <20201103203348.153465465@linuxfoundation.org>
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From: Ansuel Smith <ansuelsmth@gmail.com>

commit d3d4d028afb785e52c55024d779089654f8302e7 upstream.

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@gmail.com
Fixes: 82a823833f4e ("PCI: qcom: Add Qualcomm PCIe controller driver")
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/pci/controller/dwc/pcie-qcom.c |   13 +++++++++++++
 1 file changed, 13 insertions(+)

--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -302,6 +302,9 @@ static void qcom_pcie_deinit_2_1_0(struc
 	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);
+
 	regulator_bulk_disable(ARRAY_SIZE(res->supplies), res->supplies);
 }
 
@@ -314,6 +317,16 @@ static int qcom_pcie_init_2_1_0(struct q
 	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");