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Subject[PATCH 07/12] pcie: qcom: add tx term offset support
Date
From: Sham Muthayyan <smuthayy@codeaurora.org>

Add tx term offset support to pcie qcom driver
need in some revision of the ipq806x soc

Signed-off-by: Sham Muthayyan <smuthayy@codeaurora.org>
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
---
drivers/pci/controller/dwc/pcie-qcom.c | 61 ++++++++++++++++++++++----
1 file changed, 52 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index ecc22fd27ea6..8009e3117765 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -45,7 +45,13 @@
#define PCIE_CAP_CPL_TIMEOUT_DISABLE 0x10

#define PCIE20_PARF_PHY_CTRL 0x40
+#define PHY_CTRL_PHY_TX0_TERM_OFFSET_MASK (0x1f << 16)
+#define PHY_CTRL_PHY_TX0_TERM_OFFSET(x) (x << 16)
+
#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 +83,18 @@
#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 +115,7 @@ 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];
+ uint8_t phy_tx0_term_offset;
};

struct qcom_pcie_resources_1_0_0 {
@@ -184,6 +203,16 @@ struct qcom_pcie {

#define to_qcom_pcie(x) dev_get_drvdata((x)->dev)

+static inline void
+writel_masked(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);
@@ -277,6 +306,10 @@ static int qcom_pcie_get_resources_2_1_0(struct qcom_pcie *pcie)
if (IS_ERR(res->ext_reset))
return PTR_ERR(res->ext_reset);

+ if (of_property_read_u8(dev->of_node, "phy-tx0-term-offset",
+ &res->phy_tx0_term_offset))
+ res->phy_tx0_term_offset = 0;
+
res->phy_reset = devm_reset_control_get_exclusive(dev, "phy");
return PTR_ERR_OR_ZERO(res->phy_reset);
}
@@ -304,7 +337,6 @@ 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 = reset_control_assert(res->ahb_reset);
@@ -355,15 +387,26 @@ 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);
+ writel_masked(pcie->parf + PCIE20_PARF_PHY_CTRL, BIT(0), 0);
+
+ /* Set Tx termination offset */
+ writel_masked(pcie->parf + PCIE20_PARF_PHY_CTRL,
+ PHY_CTRL_PHY_TX0_TERM_OFFSET_MASK,
+ PHY_CTRL_PHY_TX0_TERM_OFFSET(res->phy_tx0_term_offset));
+
+ /* 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 */
+ writel_masked(pcie->parf + PCIE20_PARF_PHY_REFCLK,
+ REF_USE_PAD, REF_SSP_EN);

ret = reset_control_deassert(res->phy_reset);
if (ret) {
--
2.25.1
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