[PATCH 3/4] PCI: qcom: Add CGC disable workaround for Nord PCIe

[Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>]

Nord requires a workaround to address a timing convergence issue in the
PCIe power domain. To avoid the issue, set the CORE_CLK_CGC_DIS and
AUX_PWR_DET bits in PARF_SYS_CTRL after controller initialization.

The SLV_ACLK_CGC_DIS bit is already configured by hardware reset. This
change adds the remaining required settings as documented in
QCTDD11972446.

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
---
 drivers/pci/controller/dwc/pcie-qcom.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index d8eb52857f69..9fa7ab47c86e 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -266,6 +266,7 @@ struct qcom_pcie_cfg {
 	bool override_no_snoop;
 	bool firmware_managed;
 	bool no_l0s;
+	bool cgc_dis_workaround;
 };
 
 struct qcom_pcie_perst {
@@ -1073,11 +1074,18 @@ static int qcom_pcie_init_2_7_0(struct qcom_pcie *pcie)
 static int qcom_pcie_post_init_2_7_0(struct qcom_pcie *pcie)
 {
 	const struct qcom_pcie_cfg *pcie_cfg = pcie->cfg;
+	int val;
 
 	if (pcie_cfg->override_no_snoop)
 		writel(WR_NO_SNOOP_OVERRIDE_EN | RD_NO_SNOOP_OVERRIDE_EN,
 				pcie->parf + PARF_NO_SNOOP_OVERRIDE);
 
+	if (pcie_cfg->cgc_dis_workaround) {
+		val = readl(pcie->parf + PARF_SYS_CTRL);
+		val |= CORE_CLK_CGC_DIS | AUX_PWR_DET;
+		writel(val, pcie->parf + PARF_SYS_CTRL);
+	}
+
 	qcom_pcie_set_slot_nccs(pcie->pci);
 
 	return 0;
@@ -1604,6 +1612,13 @@ static const struct qcom_pcie_cfg cfg_2_9_0 = {
 	.ops = &ops_2_9_0,
 };
 
+static const struct qcom_pcie_cfg cfg_nord = {
+	.ops = &ops_1_9_0,
+	.override_no_snoop = true,
+	.no_l0s = true,
+	.cgc_dis_workaround = true,
+};
+
 static const struct qcom_pcie_cfg cfg_sc8280xp = {
 	.ops = &ops_1_21_0,
 	.no_l0s = true,
@@ -2282,6 +2297,7 @@ static int qcom_pcie_resume_noirq(struct device *dev)
 }
 
 static const struct of_device_id qcom_pcie_match[] = {
+	{ .compatible = "qcom,nord-pcie", .data = &cfg_nord },
 	{ .compatible = "qcom,pcie-apq8064", .data = &cfg_2_1_0 },
 	{ .compatible = "qcom,pcie-apq8084", .data = &cfg_1_0_0 },
 	{ .compatible = "qcom,pcie-ipq4019", .data = &cfg_2_4_0 },

-- 
2.34.1