Add support for Tx De-Emphasis, Tx Swing and Rx equalization definition
needed on some ipq8064 based device (Netgear R7800 for example). This
cause a total lock of the system on kernel load.

Fixes: 82a823833f4e PCI: qcom: Add Qualcomm PCIe controller driver
Signed-off-by: Ansuel Smith <ansuels...@gmail.com>
Cc: sta...@vger.kernel.org # v4.5+
---
 drivers/pci/controller/dwc/pcie-qcom.c | 47 ++++++++++++++++++++++++--
 1 file changed, 45 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c 
b/drivers/pci/controller/dwc/pcie-qcom.c
index a4fd5baada34..da8058fd1925 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 PHY_REFCLK_SSP_EN                      BIT(16)
+#define PHY_REFCLK_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
@@ -97,6 +112,12 @@ struct qcom_pcie_resources_2_1_0 {
        struct reset_control *phy_reset;
        struct reset_control *ext_reset;
        struct regulator_bulk_data supplies[QCOM_PCIE_2_1_0_MAX_SUPPLY];
+       u32 tx_deemph_gen1;
+       u32 tx_deemph_gen2_3p5db;
+       u32 tx_deemph_gen2_6db;
+       u32 tx_swing_full;
+       u32 tx_swing_low;
+       u32 rx0_eq;
 };
 
 struct qcom_pcie_resources_1_0_0 {
@@ -234,8 +255,21 @@ static int qcom_pcie_get_resources_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;
+       struct device_node *node = dev->of_node;
        int ret;
 
+       of_property_read_u32(node, "qcom,tx-deemph-gen1",
+                            &res->tx_deemph_gen1);
+       of_property_read_u32(node, "qcom,tx-deemph-gen2-3p5db",
+                            &res->tx_deemph_gen2_3p5db);
+       of_property_read_u32(node, "qcom,tx-deemph-gen2-6db",
+                            &res->tx_deemph_gen2_6db);
+       of_property_read_u32(node, "qcom,tx-swing-full",
+                            &res->tx_swing_full);
+       of_property_read_u32(node, "qcom,tx-swing-low",
+                            &res->tx_swing_low);
+       of_property_read_u32(node, "qcom,rx0-eq", &res->rx0_eq);
+
        res->supplies[0].supply = "vdda";
        res->supplies[1].supply = "vdda_phy";
        res->supplies[2].supply = "vdda_refclk";
@@ -368,9 +402,18 @@ static int qcom_pcie_init_2_1_0(struct qcom_pcie *pcie)
        /* enable PCIe clocks and resets */
        qcom_clear_and_set_dword(pcie->parf + PCIE20_PARF_PHY_CTRL, BIT(0), 0);
 
+       writel(PCS_DEEMPH_TX_DEEMPH_GEN1(res->tx_deemph_gen1) |
+              PCS_DEEMPH_TX_DEEMPH_GEN2_3_5DB(res->tx_deemph_gen2_3p5db) |
+              PCS_DEEMPH_TX_DEEMPH_GEN2_6DB(res->tx_deemph_gen2_6db),
+              pcie->parf + PCIE20_PARF_PCS_DEEMPH);
+       writel(PCS_SWING_TX_SWING_FULL(res->tx_swing_full) |
+              PCS_SWING_TX_SWING_LOW(res->tx_swing_low),
+              pcie->parf + PCIE20_PARF_PCS_SWING);
+       writel(PHY_RX0_EQ(res->rx0_eq), pcie->parf + PCIE20_PARF_CONFIG_BITS);
+
        /* enable external reference clock */
-       qcom_clear_and_set_dword(pcie->parf + PCIE20_PARF_PHY_REFCLK, 0,
-                                BIT(16));
+       qcom_clear_and_set_dword(pcie->parf + PCIE20_PARF_PHY_REFCLK,
+                                PHY_REFCLK_USE_PAD, PHY_REFCLK_SSP_EN;
 
        ret = reset_control_deassert(res->phy_reset);
        if (ret) {
-- 
2.25.1

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