linux-kernel - [PATCH 2/8] PCI: qcom: Disable write access to read only registers for IP v2.9.0

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Message-Id: <20230506073139.8789-3-manivannan.sadhasivam@linaro.org>
Date:   Sat,  6 May 2023 13:01:33 +0530
From:   Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To:     lpieralisi@...nel.org, kw@...ux.com, bhelgaas@...gle.com
Cc:     robh@...nel.org, andersson@...nel.org, konrad.dybcio@...aro.org,
        linux-pci@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org, steev@...i.org,
        quic_srichara@...cinc.com,
        Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
Subject: [PATCH 2/8] PCI: qcom: Disable write access to read only registers for IP v2.9.0

In the post init sequence of v2.9.0, write access to read only registers
are not disabled after updating the registers. Fix it by disabling the
access after register update.

Fixes: 0cf7c2efe8ac ("PCI: qcom: Add IPQ60xx support")
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
---
 drivers/pci/controller/dwc/pcie-qcom.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 01795ee7ce45..391a45d1e70a 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -1136,6 +1136,7 @@ static int qcom_pcie_post_init_2_9_0(struct qcom_pcie *pcie)
 	writel(0, pcie->parf + PARF_Q2A_FLUSH);
 
 	dw_pcie_dbi_ro_wr_en(pci);
+
 	writel(PCIE_CAP_SLOT_VAL, pci->dbi_base + offset + PCI_EXP_SLTCAP);
 
 	val = readl(pci->dbi_base + offset + PCI_EXP_LNKCAP);
@@ -1145,6 +1146,8 @@ static int qcom_pcie_post_init_2_9_0(struct qcom_pcie *pcie)
 	writel(PCI_EXP_DEVCTL2_COMP_TMOUT_DIS, pci->dbi_base + offset +
 			PCI_EXP_DEVCTL2);
 
+	dw_pcie_dbi_ro_wr_dis(pci);
+
 	for (i = 0; i < 256; i++)
 		writel(0, pcie->parf + PARF_BDF_TO_SID_TABLE_N + (4 * i));
 
-- 
2.25.1