// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * DaVinci DM816 AHCI SATA platform driver
 *
 * Copyright (C) 2017 BayLibre SAS
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/pm.h>
#include <linux/platform_device.h>
#include <linux/libata.h>
#include <linux/ahci_platform.h>

#include "ahci.h"

#define AHCI_DM816_DRV_NAME             "ahci-dm816"

#define AHCI_DM816_PHY_ENPLL(x)         ((x) << 0)
#define AHCI_DM816_PHY_MPY(x)           ((x) << 1)
#define AHCI_DM816_PHY_LOS(x)           ((x) << 12)
#define AHCI_DM816_PHY_RXCDR(x)         ((x) << 13)
#define AHCI_DM816_PHY_RXEQ(x)          ((x) << 16)
#define AHCI_DM816_PHY_TXSWING(x)       ((x) << 23)

#define AHCI_DM816_P0PHYCR_REG          0x178
#define AHCI_DM816_P1PHYCR_REG          0x1f8

#define AHCI_DM816_PLL_OUT              1500000000LU

static const unsigned long pll_mpy_table[] = {
          400,  500,  600,  800,  825, 1000, 1200,
         1250, 1500, 1600, 1650, 2000, 2200, 2500
};

static int ahci_dm816_get_mpy_bits(unsigned long refclk_rate)
{
        unsigned long pll_multiplier;
        int i;

        /*
         * We need to determine the value of the multiplier (MPY) bits.
         * In order to include the 8.25 multiplier we need to first divide
         * the refclk rate by 100.
         */
        pll_multiplier = AHCI_DM816_PLL_OUT / (refclk_rate / 100);

        for (i = 0; i < ARRAY_SIZE(pll_mpy_table); i++) {
                if (pll_mpy_table[i] == pll_multiplier)
                        return i;
        }

        /*
         * We should have divided evenly - if not, return an invalid
         * value.
         */
        return -1;
}

static int ahci_dm816_phy_init(struct ahci_host_priv *hpriv, struct device *dev)
{
        unsigned long refclk_rate;
        int mpy;
        u32 val;

        /*
         * We should have been supplied two clocks: the functional and
         * keep-alive clock and the external reference clock. We need the
         * rate of the latter to calculate the correct value of MPY bits.
         */
        if (!hpriv->clks[1]) {
                dev_err(dev, "reference clock not supplied\n");
                return -EINVAL;
        }

        refclk_rate = clk_get_rate(hpriv->clks[1]);
        if ((refclk_rate % 100) != 0) {
                dev_err(dev, "reference clock rate must be divisible by 100\n");
                return -EINVAL;
        }

        mpy = ahci_dm816_get_mpy_bits(refclk_rate);
        if (mpy < 0) {
                dev_err(dev, "can't calculate the MPY bits value\n");
                return -EINVAL;
        }

        /* Enable the PHY and configure the first HBA port. */
        val = AHCI_DM816_PHY_MPY(mpy) | AHCI_DM816_PHY_LOS(1) |
              AHCI_DM816_PHY_RXCDR(4) | AHCI_DM816_PHY_RXEQ(1) |
              AHCI_DM816_PHY_TXSWING(3) | AHCI_DM816_PHY_ENPLL(1);
        writel(val, hpriv->mmio + AHCI_DM816_P0PHYCR_REG);

        /* Configure the second HBA port. */
        val = AHCI_DM816_PHY_LOS(1) | AHCI_DM816_PHY_RXCDR(4) |
              AHCI_DM816_PHY_RXEQ(1) | AHCI_DM816_PHY_TXSWING(3);
        writel(val, hpriv->mmio + AHCI_DM816_P1PHYCR_REG);

        return 0;
}

static int ahci_dm816_softreset(struct ata_link *link,
                                unsigned int *class, unsigned long deadline)
{
        int pmp, ret;

        pmp = sata_srst_pmp(link);

        /*
         * There's an issue with the SATA controller on DM816 SoC: if we
         * enable Port Multiplier support, but the drive is connected directly
         * to the board, it can't be detected. As a workaround: if PMP is
         * enabled, we first call ahci_do_softreset() and pass it the result of
         * sata_srst_pmp(). If this call fails, we retry with pmp = 0.
         */
        ret = ahci_do_softreset(link, class, pmp, deadline, ahci_check_ready);
        if (pmp && ret == -EBUSY)
                return ahci_do_softreset(link, class, 0,
                                         deadline, ahci_check_ready);

        return ret;
}

static struct ata_port_operations ahci_dm816_port_ops = {
        .inherits = &ahci_platform_ops,
        .softreset = ahci_dm816_softreset,
};

static const struct ata_port_info ahci_dm816_port_info = {
        .flags          = AHCI_FLAG_COMMON,
        .pio_mask       = ATA_PIO4,
        .udma_mask      = ATA_UDMA6,
        .port_ops       = &ahci_dm816_port_ops,
};

static struct scsi_host_template ahci_dm816_platform_sht = {
        AHCI_SHT(AHCI_DM816_DRV_NAME),
};

static int ahci_dm816_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct ahci_host_priv *hpriv;
        int rc;

        hpriv = ahci_platform_get_resources(pdev, 0);
        if (IS_ERR(hpriv))
                return PTR_ERR(hpriv);

        rc = ahci_platform_enable_resources(hpriv);
        if (rc)
                return rc;

        rc = ahci_dm816_phy_init(hpriv, dev);
        if (rc)
                goto disable_resources;

        rc = ahci_platform_init_host(pdev, hpriv,
                                     &ahci_dm816_port_info,
                                     &ahci_dm816_platform_sht);
        if (rc)
                goto disable_resources;

        return 0;

disable_resources:
        ahci_platform_disable_resources(hpriv);

        return rc;
}

static SIMPLE_DEV_PM_OPS(ahci_dm816_pm_ops,
                         ahci_platform_suspend,
                         ahci_platform_resume);

static const struct of_device_id ahci_dm816_of_match[] = {
        { .compatible = "ti,dm816-ahci", },
        { },
};
MODULE_DEVICE_TABLE(of, ahci_dm816_of_match);

static struct platform_driver ahci_dm816_driver = {
        .probe = ahci_dm816_probe,
        .remove = ata_platform_remove_one,
        .driver = {
                .name = AHCI_DM816_DRV_NAME,
                .of_match_table = ahci_dm816_of_match,
                .pm = &ahci_dm816_pm_ops,
        },
};
module_platform_driver(ahci_dm816_driver);

MODULE_DESCRIPTION("DaVinci DM816 AHCI SATA platform driver");
MODULE_AUTHOR("Bartosz Golaszewski <bgolaszewski@baylibre.com>");
MODULE_LICENSE("GPL");