// SPDX-License-Identifier: GPL-2.0-only OR BSD-3-Clause

/* MDIO support for Mellanox Gigabit Ethernet driver
 *
 * Copyright (C) 2020-2021 NVIDIA CORPORATION & AFFILIATES
 */

#include <linux/acpi.h>
#include <linux/bitfield.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/ioport.h>
#include <linux/irqreturn.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/phy.h>
#include <linux/platform_device.h>
#include <linux/property.h>

#include "mlxbf_gige.h"
#include "mlxbf_gige_regs.h"
#include "mlxbf_gige_mdio_bf2.h"
#include "mlxbf_gige_mdio_bf3.h"

static struct mlxbf_gige_mdio_gw mlxbf_gige_mdio_gw_t[] = {
        [MLXBF_GIGE_VERSION_BF2] = {
                .gw_address = MLXBF2_GIGE_MDIO_GW_OFFSET,
                .read_data_address = MLXBF2_GIGE_MDIO_GW_OFFSET,
                .busy = {
                        .mask = MLXBF2_GIGE_MDIO_GW_BUSY_MASK,
                        .shift = MLXBF2_GIGE_MDIO_GW_BUSY_SHIFT,
                },
                .read_data = {
                        .mask = MLXBF2_GIGE_MDIO_GW_AD_MASK,
                        .shift = MLXBF2_GIGE_MDIO_GW_AD_SHIFT,
                },
                .write_data = {
                        .mask = MLXBF2_GIGE_MDIO_GW_AD_MASK,
                        .shift = MLXBF2_GIGE_MDIO_GW_AD_SHIFT,
                },
                .devad = {
                        .mask = MLXBF2_GIGE_MDIO_GW_DEVAD_MASK,
                        .shift = MLXBF2_GIGE_MDIO_GW_DEVAD_SHIFT,
                },
                .partad = {
                        .mask = MLXBF2_GIGE_MDIO_GW_PARTAD_MASK,
                        .shift = MLXBF2_GIGE_MDIO_GW_PARTAD_SHIFT,
                },
                .opcode = {
                        .mask = MLXBF2_GIGE_MDIO_GW_OPCODE_MASK,
                        .shift = MLXBF2_GIGE_MDIO_GW_OPCODE_SHIFT,
                },
                .st1 = {
                        .mask = MLXBF2_GIGE_MDIO_GW_ST1_MASK,
                        .shift = MLXBF2_GIGE_MDIO_GW_ST1_SHIFT,
                },
        },
        [MLXBF_GIGE_VERSION_BF3] = {
                .gw_address = MLXBF3_GIGE_MDIO_GW_OFFSET,
                .read_data_address = MLXBF3_GIGE_MDIO_DATA_READ,
                .busy = {
                        .mask = MLXBF3_GIGE_MDIO_GW_BUSY_MASK,
                        .shift = MLXBF3_GIGE_MDIO_GW_BUSY_SHIFT,
                },
                .read_data = {
                        .mask = MLXBF3_GIGE_MDIO_GW_DATA_READ_MASK,
                        .shift = MLXBF3_GIGE_MDIO_GW_DATA_READ_SHIFT,
                },
                .write_data = {
                        .mask = MLXBF3_GIGE_MDIO_GW_DATA_MASK,
                        .shift = MLXBF3_GIGE_MDIO_GW_DATA_SHIFT,
                },
                .devad = {
                        .mask = MLXBF3_GIGE_MDIO_GW_DEVAD_MASK,
                        .shift = MLXBF3_GIGE_MDIO_GW_DEVAD_SHIFT,
                },
                .partad = {
                        .mask = MLXBF3_GIGE_MDIO_GW_PARTAD_MASK,
                        .shift = MLXBF3_GIGE_MDIO_GW_PARTAD_SHIFT,
                },
                .opcode = {
                        .mask = MLXBF3_GIGE_MDIO_GW_OPCODE_MASK,
                        .shift = MLXBF3_GIGE_MDIO_GW_OPCODE_SHIFT,
                },
                .st1 = {
                        .mask = MLXBF3_GIGE_MDIO_GW_ST1_MASK,
                        .shift = MLXBF3_GIGE_MDIO_GW_ST1_SHIFT,
                },
        },
};

#define MLXBF_GIGE_MDIO_FREQ_REFERENCE 156250000ULL
#define MLXBF_GIGE_MDIO_COREPLL_CONST  16384ULL
#define MLXBF_GIGE_MDC_CLK_NS          400
#define MLXBF_GIGE_MDIO_PLL_I1CLK_REG1 0x4
#define MLXBF_GIGE_MDIO_PLL_I1CLK_REG2 0x8
#define MLXBF_GIGE_MDIO_CORE_F_SHIFT   0
#define MLXBF_GIGE_MDIO_CORE_F_MASK    GENMASK(25, 0)
#define MLXBF_GIGE_MDIO_CORE_R_SHIFT   26
#define MLXBF_GIGE_MDIO_CORE_R_MASK    GENMASK(31, 26)
#define MLXBF_GIGE_MDIO_CORE_OD_SHIFT  0
#define MLXBF_GIGE_MDIO_CORE_OD_MASK   GENMASK(3, 0)

/* Support clause 22 */
#define MLXBF_GIGE_MDIO_CL22_ST1        0x1
#define MLXBF_GIGE_MDIO_CL22_WRITE      0x1
#define MLXBF_GIGE_MDIO_CL22_READ       0x2

/* Busy bit is set by software and cleared by hardware */
#define MLXBF_GIGE_MDIO_SET_BUSY        0x1

#define MLXBF_GIGE_BF2_COREPLL_ADDR 0x02800c30
#define MLXBF_GIGE_BF2_COREPLL_SIZE 0x0000000c
#define MLXBF_GIGE_BF3_COREPLL_ADDR 0x13409824
#define MLXBF_GIGE_BF3_COREPLL_SIZE 0x00000010

static struct resource corepll_params[] = {
        [MLXBF_GIGE_VERSION_BF2] = {
                .start = MLXBF_GIGE_BF2_COREPLL_ADDR,
                .end = MLXBF_GIGE_BF2_COREPLL_ADDR + MLXBF_GIGE_BF2_COREPLL_SIZE - 1,
                .name = "COREPLL_RES"
        },
        [MLXBF_GIGE_VERSION_BF3] = {
                .start = MLXBF_GIGE_BF3_COREPLL_ADDR,
                .end = MLXBF_GIGE_BF3_COREPLL_ADDR + MLXBF_GIGE_BF3_COREPLL_SIZE - 1,
                .name = "COREPLL_RES"
        }
};

/* Returns core clock i1clk in Hz */
static u64 calculate_i1clk(struct mlxbf_gige *priv)
{
        u8 core_od, core_r;
        u64 freq_output;
        u32 reg1, reg2;
        u32 core_f;

        reg1 = readl(priv->clk_io + MLXBF_GIGE_MDIO_PLL_I1CLK_REG1);
        reg2 = readl(priv->clk_io + MLXBF_GIGE_MDIO_PLL_I1CLK_REG2);

        core_f = (reg1 & MLXBF_GIGE_MDIO_CORE_F_MASK) >>
                MLXBF_GIGE_MDIO_CORE_F_SHIFT;
        core_r = (reg1 & MLXBF_GIGE_MDIO_CORE_R_MASK) >>
                MLXBF_GIGE_MDIO_CORE_R_SHIFT;
        core_od = (reg2 & MLXBF_GIGE_MDIO_CORE_OD_MASK) >>
                MLXBF_GIGE_MDIO_CORE_OD_SHIFT;

        /* Compute PLL output frequency as follow:
         *
         *                                     CORE_F / 16384
         * freq_output = freq_reference * ----------------------------
         *                              (CORE_R + 1) * (CORE_OD + 1)
         */
        freq_output = div_u64((MLXBF_GIGE_MDIO_FREQ_REFERENCE * core_f),
                              MLXBF_GIGE_MDIO_COREPLL_CONST);
        freq_output = div_u64(freq_output, (core_r + 1) * (core_od + 1));

        return freq_output;
}

/* Formula for encoding the MDIO period. The encoded value is
 * passed to the MDIO config register.
 *
 * mdc_clk = 2*(val + 1)*(core clock in sec)
 *
 * i1clk is in Hz:
 * 400 ns = 2*(val + 1)*(1/i1clk)
 *
 * val = (((400/10^9) / (1/i1clk) / 2) - 1)
 * val = (400/2 * i1clk)/10^9 - 1
 */
static u8 mdio_period_map(struct mlxbf_gige *priv)
{
        u8 mdio_period;
        u64 i1clk;

        i1clk = calculate_i1clk(priv);

        mdio_period = div_u64((MLXBF_GIGE_MDC_CLK_NS >> 1) * i1clk, 1000000000) - 1;

        return mdio_period;
}

static u32 mlxbf_gige_mdio_create_cmd(struct mlxbf_gige_mdio_gw *mdio_gw, u16 data, int phy_add,
                                      int phy_reg, u32 opcode)
{
        u32 gw_reg = 0;

        gw_reg |= ((data << mdio_gw->write_data.shift) &
                   mdio_gw->write_data.mask);
        gw_reg |= ((phy_reg << mdio_gw->devad.shift) &
                   mdio_gw->devad.mask);
        gw_reg |= ((phy_add << mdio_gw->partad.shift) &
                   mdio_gw->partad.mask);
        gw_reg |= ((opcode << mdio_gw->opcode.shift) &
                   mdio_gw->opcode.mask);
        gw_reg |= ((MLXBF_GIGE_MDIO_CL22_ST1 << mdio_gw->st1.shift) &
                   mdio_gw->st1.mask);
        gw_reg |= ((MLXBF_GIGE_MDIO_SET_BUSY << mdio_gw->busy.shift) &
                   mdio_gw->busy.mask);

        return gw_reg;
}

static int mlxbf_gige_mdio_read(struct mii_bus *bus, int phy_add, int phy_reg)
{
        struct mlxbf_gige *priv = bus->priv;
        u32 cmd;
        int ret;
        u32 val;

        /* Send mdio read request */
        cmd = mlxbf_gige_mdio_create_cmd(priv->mdio_gw, 0, phy_add, phy_reg,
                                         MLXBF_GIGE_MDIO_CL22_READ);

        writel(cmd, priv->mdio_io + priv->mdio_gw->gw_address);

        ret = readl_poll_timeout_atomic(priv->mdio_io + priv->mdio_gw->gw_address,
                                        val, !(val & priv->mdio_gw->busy.mask),
                                        5, 1000000);

        if (ret) {
                writel(0, priv->mdio_io + priv->mdio_gw->gw_address);
                return ret;
        }

        ret = readl(priv->mdio_io + priv->mdio_gw->read_data_address);
        /* Only return ad bits of the gw register */
        ret &= priv->mdio_gw->read_data.mask;

        /* The MDIO lock is set on read. To release it, clear gw register */
        writel(0, priv->mdio_io + priv->mdio_gw->gw_address);

        return ret;
}

static int mlxbf_gige_mdio_write(struct mii_bus *bus, int phy_add,
                                 int phy_reg, u16 val)
{
        struct mlxbf_gige *priv = bus->priv;
        u32 temp;
        u32 cmd;
        int ret;

        /* Send mdio write request */
        cmd = mlxbf_gige_mdio_create_cmd(priv->mdio_gw, val, phy_add, phy_reg,
                                         MLXBF_GIGE_MDIO_CL22_WRITE);
        writel(cmd, priv->mdio_io + priv->mdio_gw->gw_address);

        /* If the poll timed out, drop the request */
        ret = readl_poll_timeout_atomic(priv->mdio_io + priv->mdio_gw->gw_address,
                                        temp, !(temp & priv->mdio_gw->busy.mask),
                                        5, 1000000);

        /* The MDIO lock is set on read. To release it, clear gw register */
        writel(0, priv->mdio_io + priv->mdio_gw->gw_address);

        return ret;
}

static void mlxbf_gige_mdio_cfg(struct mlxbf_gige *priv)
{
        u8 mdio_period;
        u32 val;

        mdio_period = mdio_period_map(priv);

        if (priv->hw_version == MLXBF_GIGE_VERSION_BF2) {
                val = MLXBF2_GIGE_MDIO_CFG_VAL;
                val |= FIELD_PREP(MLXBF2_GIGE_MDIO_CFG_MDC_PERIOD_MASK, mdio_period);
                writel(val, priv->mdio_io + MLXBF2_GIGE_MDIO_CFG_OFFSET);
        } else {
                val = FIELD_PREP(MLXBF3_GIGE_MDIO_CFG_MDIO_MODE_MASK, 1) |
                      FIELD_PREP(MLXBF3_GIGE_MDIO_CFG_MDIO_FULL_DRIVE_MASK, 1);
                writel(val, priv->mdio_io + MLXBF3_GIGE_MDIO_CFG_REG0);
                val = FIELD_PREP(MLXBF3_GIGE_MDIO_CFG_MDC_PERIOD_MASK, mdio_period);
                writel(val, priv->mdio_io + MLXBF3_GIGE_MDIO_CFG_REG1);
                val = FIELD_PREP(MLXBF3_GIGE_MDIO_CFG_MDIO_IN_SAMP_MASK, 6) |
                      FIELD_PREP(MLXBF3_GIGE_MDIO_CFG_MDIO_OUT_SAMP_MASK, 13);
                writel(val, priv->mdio_io + MLXBF3_GIGE_MDIO_CFG_REG2);
        }
}

int mlxbf_gige_mdio_probe(struct platform_device *pdev, struct mlxbf_gige *priv)
{
        struct device *dev = &pdev->dev;
        struct resource *res;
        int ret;

        if (priv->hw_version > MLXBF_GIGE_VERSION_BF3)
                return -ENODEV;

        priv->mdio_io = devm_platform_ioremap_resource(pdev, MLXBF_GIGE_RES_MDIO9);
        if (IS_ERR(priv->mdio_io))
                return PTR_ERR(priv->mdio_io);

        /* clk resource shared with other drivers so cannot use
         * devm_platform_ioremap_resource
         */
        res = platform_get_resource(pdev, IORESOURCE_MEM, MLXBF_GIGE_RES_CLK);
        if (!res) {
                /* For backward compatibility with older ACPI tables, also keep
                 * CLK resource internal to the driver.
                 */
                res = &corepll_params[priv->hw_version];
        }

        priv->clk_io = devm_ioremap(dev, res->start, resource_size(res));
        if (!priv->clk_io)
                return -ENOMEM;

        priv->mdio_gw = &mlxbf_gige_mdio_gw_t[priv->hw_version];

        mlxbf_gige_mdio_cfg(priv);

        priv->mdiobus = devm_mdiobus_alloc(dev);
        if (!priv->mdiobus) {
                dev_err(dev, "Failed to alloc MDIO bus\n");
                return -ENOMEM;
        }

        priv->mdiobus->name = "mlxbf-mdio";
        priv->mdiobus->read = mlxbf_gige_mdio_read;
        priv->mdiobus->write = mlxbf_gige_mdio_write;
        priv->mdiobus->parent = dev;
        priv->mdiobus->priv = priv;
        snprintf(priv->mdiobus->id, MII_BUS_ID_SIZE, "%s",
                 dev_name(dev));

        ret = mdiobus_register(priv->mdiobus);
        if (ret)
                dev_err(dev, "Failed to register MDIO bus\n");

        return ret;
}

void mlxbf_gige_mdio_remove(struct mlxbf_gige *priv)
{
        mdiobus_unregister(priv->mdiobus);
}