linux-kernel - [PATCH v2 07/10] PCIe: qcom: fix init problem with missing PARF programming

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Message-Id: <20200402121148.1767-8-ansuelsmth@gmail.com>
Date:   Thu,  2 Apr 2020 14:11:44 +0200
From:   Ansuel Smith <ansuelsmth@...il.com>
To:     Andy Gross <agross@...nel.org>
Cc:     Ansuel Smith <ansuelsmth@...il.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Stanimir Varbanov <svarbanov@...sol.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Andrew Murray <amurray@...goodpenguin.co.uk>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        linux-arm-msm@...r.kernel.org, linux-pci@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 07/10] PCIe: qcom: fix init problem with missing PARF programming

PARF programming was missing and this cause initilizzation problem on
some ipq806x based device (Netgear R7800 for example). This cause a
total lock of the system on kernel load.

Fixes: 82a82383 PCI: qcom: Add Qualcomm PCIe controller driver
Signed-off-by: Ansuel Smith <ansuelsmth@...il.com>
---
 drivers/pci/controller/dwc/pcie-qcom.c | 48 +++++++++++++++++++++-----
 1 file changed, 39 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 211a1aa7d0f1..77b1ab7e23a3 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -46,6 +46,9 @@
 
 #define PCIE20_PARF_PHY_CTRL			0x40
 #define PCIE20_PARF_PHY_REFCLK			0x4C
+#define REF_SSP_EN				BIT(16)
+#define REF_USE_PAD				BIT(12)
+
 #define PCIE20_PARF_DBI_BASE_ADDR		0x168
 #define PCIE20_PARF_SLV_ADDR_SPACE_SIZE		0x16C
 #define PCIE20_PARF_MHI_CLOCK_RESET_CTRL	0x174
@@ -77,6 +80,18 @@
 #define DBI_RO_WR_EN				1
 
 #define PERST_DELAY_US				1000
+/* PARF registers */
+#define PCIE20_PARF_PCS_DEEMPH			0x34
+#define PCS_DEEMPH_TX_DEEMPH_GEN1(x)		(x << 16)
+#define PCS_DEEMPH_TX_DEEMPH_GEN2_3_5DB(x)	(x << 8)
+#define PCS_DEEMPH_TX_DEEMPH_GEN2_6DB(x)	(x << 0)
+
+#define PCIE20_PARF_PCS_SWING			0x38
+#define PCS_SWING_TX_SWING_FULL(x)		(x << 8)
+#define PCS_SWING_TX_SWING_LOW(x)		(x << 0)
+
+#define PCIE20_PARF_CONFIG_BITS		0x50
+#define PHY_RX0_EQ(x)				(x << 24)
 
 #define PCIE20_v3_PARF_SLV_ADDR_SPACE_SIZE	0x358
 #define SLV_ADDR_SPACE_SZ			0x10000000
@@ -184,6 +199,16 @@ struct qcom_pcie {
 
 #define to_qcom_pcie(x)		dev_get_drvdata((x)->dev)
 
+static inline void qcom_clear_and_set_dword(void __iomem *addr,
+				 u32 clear_mask, u32 set_mask)
+{
+	u32 val = readl(addr);
+
+	val &= ~clear_mask;
+	val |= set_mask;
+	writel(val, addr);
+}
+
 static void qcom_ep_reset_assert(struct qcom_pcie *pcie)
 {
 	gpiod_set_value_cansleep(pcie->reset, 1);
@@ -304,7 +329,6 @@ static int qcom_pcie_init_2_1_0(struct qcom_pcie *pcie)
 	struct qcom_pcie_resources_2_1_0 *res = &pcie->res.v2_1_0;
 	struct dw_pcie *pci = pcie->pci;
 	struct device *dev = pci->dev;
-	u32 val;
 	int ret;
 
 	ret = regulator_bulk_enable(ARRAY_SIZE(res->supplies), res->supplies);
@@ -355,15 +379,21 @@ static int qcom_pcie_init_2_1_0(struct qcom_pcie *pcie)
 		goto err_deassert_ahb;
 	}
 
-	/* enable PCIe clocks and resets */
-	val = readl(pcie->parf + PCIE20_PARF_PHY_CTRL);
-	val &= ~BIT(0);
-	writel(val, pcie->parf + PCIE20_PARF_PHY_CTRL);
+	qcom_clear_and_set_dword(pcie->parf + PCIE20_PARF_PHY_CTRL, BIT(0), 0);
+
+	/* PARF programming */
+	writel(PCS_DEEMPH_TX_DEEMPH_GEN1(0x18) |
+	       PCS_DEEMPH_TX_DEEMPH_GEN2_3_5DB(0x18) |
+	       PCS_DEEMPH_TX_DEEMPH_GEN2_6DB(0x22),
+	       pcie->parf + PCIE20_PARF_PCS_DEEMPH);
+	writel(PCS_SWING_TX_SWING_FULL(0x78) |
+	       PCS_SWING_TX_SWING_LOW(0x78),
+	       pcie->parf + PCIE20_PARF_PCS_SWING);
+	writel(PHY_RX0_EQ(0x4), pcie->parf + PCIE20_PARF_CONFIG_BITS);
 
-	/* enable external reference clock */
-	val = readl(pcie->parf + PCIE20_PARF_PHY_REFCLK);
-	val |= BIT(16);
-	writel(val, pcie->parf + PCIE20_PARF_PHY_REFCLK);
+	/* enable reference clock */
+	qcom_clear_and_set_dword(pcie->parf + PCIE20_PARF_PHY_REFCLK,
+		      REF_USE_PAD, REF_SSP_EN);
 
 	ret = reset_control_deassert(res->phy_reset);
 	if (ret) {
-- 
2.25.1