linux-kernel - [PATCH v3 2/8] PCI: qcom: Disable write access to read only registers for IP v2.9.0

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Message-Id: <20230601163900.15500-3-manivannan.sadhasivam@linaro.org>
Date:   Thu,  1 Jun 2023 22:08:54 +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>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Subject: [PATCH v3 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.

While at it, let's also add a newline after existing dw_pcie_dbi_ro_wr_en()
guard function to align with rest of the driver.

Fixes: 0cf7c2efe8ac ("PCI: qcom: Add IPQ60xx support")
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
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