mmc/host/dw_mmc-rockchip.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
 */

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/mmc/host.h>
#include <linux/of_address.h>
#include <linux/mmc/slot-gpio.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>

#include "dw_mmc.h"
#include "dw_mmc-pltfm.h"

#define RK3288_CLKGEN_DIV 2
#define RK3288_CLKGEN_MUL 2
#define RK_NINTY_DEGREE_PHASE 90
#define RK_ONE_HUNDRED_EIGHTY_DEGREE_PHASE 180
#define RK_TWO_HUNDRED_SEVENTY_DEGREE_PHASE 270
#define RK_THREE_HUNDRED_SIXTY_DEGREE_PHASE 360
#define RK3288_PHASE_DIV 2
#define RK3288_PHASE_MUL 20
#define RK3288_CLK_MIN_ONE 375000
#define RK3288_CLK_MIN_TWO 100000
#define RK_SDIO_ID0_SLOT_NUM 8
#define PM_AUTOSUSPEND_DELAY_COUNT 50

struct dw_mci_rockchip_priv_data {
    struct clk *drv_clk;
    struct clk *sample_clk;
    int default_sample_phase;
    int num_phases;
    bool use_v2_tuning;
    int last_degree;
    u32 f_min;
};

static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
{
    struct dw_mci_rockchip_priv_data *priv = host->priv;
    int ret;
    unsigned int cclkin;
    u32 bus_hz;

    if (ios->clock == 0) {
        return;
    }

    /*
     * cclkin: source clock of mmc controller
     * bus_hz: card interface clock generated by CLKGEN
     * bus_hz = cclkin / RK3288_CLKGEN_DIV
     * ios->clock = (div == 0) ? bus_hz : (bus_hz / (2 * div))
     *
     * Note: div can only be 0 or 1, but div must be set to 1 for eMMC
     * DDR52 8-bit mode.
     */
    if (ios->clock < priv->f_min) {
        ios->clock = priv->f_min;
    }

    if (ios->bus_width == MMC_BUS_WIDTH_8 && ios->timing == MMC_TIMING_MMC_DDR52) {
        cclkin = RK3288_CLKGEN_MUL * ios->clock * RK3288_CLKGEN_DIV;
    } else {
        cclkin = ios->clock * RK3288_CLKGEN_DIV;
    }

    ret = clk_set_rate(host->ciu_clk, cclkin);
    if (ret) {
        dev_warn(host->dev, "failed to set rate %uHz\n", ios->clock);
    }

    bus_hz = clk_get_rate(host->ciu_clk) / RK3288_CLKGEN_DIV;
    if (bus_hz != host->bus_hz) {
        host->bus_hz = bus_hz;
        /* force dw_mci_setup_bus() */
        host->current_speed = 0;
    }

    /* Make sure we use phases which we can enumerate with */
    if (!IS_ERR(priv->sample_clk) && ios->timing <= MMC_TIMING_SD_HS) {
        clk_set_phase(priv->sample_clk, priv->default_sample_phase);
    }

    /*
     * Set the drive phase offset based on speed mode to achieve hold times.
     *
     * NOTE: this is _not_ a value that is dynamically tuned and is also
     * _not_ a value that will vary from board to board.  It is a value
     * that could vary between different SoC models if they had massively
     * different output clock delays inside their dw_mmc IP block (delay_o),
     * but since it's OK to overshoot a little we don't need to do complex
     * calculations and can pick values that will just work for everyone.
     *
     * When picking values we'll stick with picking 0/90/180/270 since
     * those can be made very accurately on all known Rockchip SoCs.
     *
     * Note that these values match values from the DesignWare Databook
     * tables for the most part except for SDR12 and "ID mode".  For those
     * two modes the databook calculations assume a clock in of 50MHz.  As
     * seen above, we always use a clock in rate that is exactly the
     * card's input clock (times RK3288_CLKGEN_DIV, but that gets divided
     * back out before the controller sees it).
     *
     * From measurement of a single device, it appears that delay_o is
     * about .5 ns.  Since we try to leave a bit of margin, it's expected
     * that numbers here will be fine even with much larger delay_o
     * (the 1.4 ns assumed by the DesignWare Databook would result in the
     * same results, for instance).
     */
    if (!IS_ERR(priv->drv_clk)) {
        int phase;

        /*
         * In almost all cases a 90 degree phase offset will provide
         * sufficient hold times across all valid input clock rates
         * assuming delay_o is not absurd for a given SoC.  We'll use
         * that as a default.
         */
        phase = RK_NINTY_DEGREE_PHASE;

        switch (ios->timing) {
            case MMC_TIMING_MMC_DDR52:
                /*
                 * Since clock in rate with MMC_DDR52 is doubled when
                 * bus width is 8 we need to double the phase offset
                 * to get the same timings.
                 */
                if (ios->bus_width == MMC_BUS_WIDTH_8) {
                    phase = RK_ONE_HUNDRED_EIGHTY_DEGREE_PHASE;
                }
                break;
            case MMC_TIMING_UHS_SDR104:
            case MMC_TIMING_MMC_HS200:
                /*
                 * In the case of 150 MHz clock (typical max for
                 * Rockchip SoCs), 90 degree offset will add a delay
                 * of 1.67 ns.  That will meet min hold time of .8 ns
                 * as long as clock output delay is < .87 ns.  On
                 * SoCs measured this seems to be OK, but it doesn't
                 * hurt to give margin here, so we use 180.
                 */
                phase = RK_ONE_HUNDRED_EIGHTY_DEGREE_PHASE;
                break;
        }

        clk_set_phase(priv->drv_clk, phase);
    }
}

#define TUNING_ITERATION_TO_PHASE(i, num_phases) (DIV_ROUND_UP((i)*RK_THREE_HUNDRED_SIXTY_DEGREE_PHASE, num_phases))

static int dw_mci_v2_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
{
    struct dw_mci *host = slot->host;
    struct dw_mci_rockchip_priv_data *priv = host->priv;
    struct mmc_host *mmc = slot->mmc;
    u32 degrees[4] = {RK_NINTY_DEGREE_PHASE, RK_ONE_HUNDRED_EIGHTY_DEGREE_PHASE, RK_TWO_HUNDRED_SEVENTY_DEGREE_PHASE,
                      RK_THREE_HUNDRED_SIXTY_DEGREE_PHASE};
    int i;
    static bool inherit = true;

    if (inherit) {
        inherit = false;
        i = clk_get_phase(priv->sample_clk) / RK_NINTY_DEGREE_PHASE - 1;
        goto done;
    }

    /* v2 only support 4 degrees in theory */
    for (i = 0; i < ARRAY_SIZE(degrees); i++) {
        if (degrees[i] == priv->last_degree) {
            continue;
        }

        clk_set_phase(priv->sample_clk, degrees[i]);
        if (!mmc_send_tuning(mmc, opcode, NULL)) {
            break;
        }
    }

    if (i == ARRAY_SIZE(degrees)) {
        dev_warn(host->dev, "All phases bad!");
        return -EIO;
    }

done:
    dev_info(host->dev, "Successfully tuned phase to %d\n", degrees[i]);
    priv->last_degree = degrees[i];
    return 0;
}

static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
{
    struct dw_mci *host = slot->host;
    struct dw_mci_rockchip_priv_data *priv = host->priv;
    struct mmc_host *mmc = slot->mmc;
    int ret = 0;
    int i;
    bool v, prev_v = 0, first_v;
    struct range_t {
        int start;
        int end; /* inclusive */
    };
    struct range_t *ranges;
    unsigned int range_count = 0;
    int longest_range_len = -1;
    int longest_range = -1;
    int middle_phase;

    if (IS_ERR(priv->sample_clk)) {
        dev_err(host->dev, "Tuning clock (sample_clk) not defined.\n");
        return -EIO;
    }

    if (priv->use_v2_tuning) {
        ret = dw_mci_v2_execute_tuning(slot, opcode);
        if (!ret) {
            return 0;
        }
        /* Otherwise we continue using fine tuning */
    }

    ranges = kmalloc_array(priv->num_phases / RK3288_PHASE_DIV + 1, sizeof(*ranges), GFP_KERNEL);
    if (!ranges) {
        return -ENOMEM;
    }

    /* Try each phase and extract good ranges */
    for (i = 0; i < priv->num_phases;) {
        clk_set_phase(priv->sample_clk, TUNING_ITERATION_TO_PHASE(i, priv->num_phases));

        v = !mmc_send_tuning(mmc, opcode, NULL);

        if (i == 0) {
            first_v = v;
        }

        if ((!prev_v) && v) {
            range_count++;
            ranges[range_count - 1].start = i;
        }
        if (v) {
            ranges[range_count - 1].end = i;
            i++;
        } else if (i == priv->num_phases - 1) {
            /* No extra skipping rules if we're at the end */
            i++;
        } else {
            /*
             * No need to check too close to an invalid
             * one since testing bad phases is slow.  Skip
             * 20 degrees.
             */
            i += DIV_ROUND_UP(RK3288_PHASE_MUL * priv->num_phases, RK_THREE_HUNDRED_SIXTY_DEGREE_PHASE);
            /* Always test the last one */
            if (i >= priv->num_phases) {
                i = priv->num_phases - 1;
            }
        }

        prev_v = v;
    }

    if (range_count == 0) {
        dev_warn(host->dev, "All phases bad!");
        ret = -EIO;
        goto free;
    }

    /* wrap around case, merge the end points */
    if ((range_count > 1) && first_v && v) {
        ranges[0].start = ranges[range_count - 1].start;
        range_count--;
    }

    if (ranges[0].start == 0 && ranges[0].end == priv->num_phases - 1) {
        clk_set_phase(priv->sample_clk, priv->default_sample_phase);
        dev_info(host->dev, "All phases work, using default phase %d.", priv->default_sample_phase);
        goto free;
    }

    /* Find the longest range */
    for (i = 0; i < range_count; i++) {
        int len = (ranges[i].end - ranges[i].start + 1);

        if (len < 0) {
            len += priv->num_phases;
        }

        if (longest_range_len < len) {
            longest_range_len = len;
            longest_range = i;
        }

        dev_dbg(host->dev, "Good phase range %d-%d (%d len)\n",
                TUNING_ITERATION_TO_PHASE(ranges[i].start, priv->num_phases),
                TUNING_ITERATION_TO_PHASE(ranges[i].end, priv->num_phases), len);
    }

    dev_dbg(host->dev, "Best phase range %d-%d (%d len)\n",
            TUNING_ITERATION_TO_PHASE(ranges[longest_range].start, priv->num_phases),
            TUNING_ITERATION_TO_PHASE(ranges[longest_range].end, priv->num_phases), longest_range_len);

    middle_phase = ranges[longest_range].start + longest_range_len / RK3288_PHASE_DIV;
    middle_phase %= priv->num_phases;
    dev_info(host->dev, "Successfully tuned phase to %d\n", TUNING_ITERATION_TO_PHASE(middle_phase, priv->num_phases));

    clk_set_phase(priv->sample_clk, TUNING_ITERATION_TO_PHASE(middle_phase, priv->num_phases));

free:
    kfree(ranges);
    return ret;
}

static int dw_mci_rk3288_parse_dt(struct dw_mci *host)
{
    struct device_node *np = host->dev->of_node;
    struct dw_mci_rockchip_priv_data *priv;

    priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
    if (!priv) {
        return -ENOMEM;
    }

    /*
     * RK356X SoCs only support 375KHz for ID mode, so any clk request
     * that less than 1.6MHz(2 * 400KHz * RK3288_CLKGEN_DIV) should be
     * wrapped  into 375KHz
     */
    if (of_device_is_compatible(host->dev->of_node, "rockchip,rk3568-dw-mshc")) {
        priv->f_min = RK3288_CLK_MIN_ONE;
    } else {
        priv->f_min = RK3288_CLK_MIN_TWO;
    }

    if (of_property_read_u32(np, "rockchip,desired-num-phases", &priv->num_phases)) {
        priv->num_phases = RK_THREE_HUNDRED_SIXTY_DEGREE_PHASE;
    }

    if (of_property_read_u32(np, "rockchip,default-sample-phase", &priv->default_sample_phase)) {
        priv->default_sample_phase = 0;
    }

    if (of_property_read_bool(np, "rockchip,use-v2-tuning")) {
        priv->use_v2_tuning = true;
    }

    priv->drv_clk = devm_clk_get(host->dev, "ciu-drive");
    if (IS_ERR(priv->drv_clk)) {
        dev_dbg(host->dev, "ciu-drive not available\n");
    }

    priv->sample_clk = devm_clk_get(host->dev, "ciu-sample");
    if (IS_ERR(priv->sample_clk)) {
        dev_dbg(host->dev, "ciu-sample not available\n");
    }

    host->priv = priv;

    return 0;
}

static int dw_mci_rockchip_init(struct dw_mci *host)
{
    /* It is slot 8 on Rockchip SoCs */
    host->sdio_id0 = RK_SDIO_ID0_SLOT_NUM;

    if (of_device_is_compatible(host->dev->of_node, "rockchip,rk3288-dw-mshc")) {
        host->bus_hz /= RK3288_CLKGEN_DIV;
    }

    host->need_xfer_timer = true;
    return 0;
}

/* Common capabilities of RK3288 SoC */
static unsigned long dw_mci_rk3288_dwmmc_caps[4] = {
    MMC_CAP_CMD23,
    MMC_CAP_CMD23,
    MMC_CAP_CMD23,
    MMC_CAP_CMD23,
};

static const struct dw_mci_drv_data rk2928_drv_data = {
    .init = dw_mci_rockchip_init,
};

static const struct dw_mci_drv_data rk3288_drv_data = {
    .caps = dw_mci_rk3288_dwmmc_caps,
    .num_caps = ARRAY_SIZE(dw_mci_rk3288_dwmmc_caps),
    .set_ios = dw_mci_rk3288_set_ios,
    .execute_tuning = dw_mci_rk3288_execute_tuning,
    .parse_dt = dw_mci_rk3288_parse_dt,
    .init = dw_mci_rockchip_init,
};

static const struct of_device_id dw_mci_rockchip_match[] = {
    {.compatible = "rockchip,rk2928-dw-mshc", .data = &rk2928_drv_data},
    {.compatible = "rockchip,rk3288-dw-mshc", .data = &rk3288_drv_data},
    {},
};
MODULE_DEVICE_TABLE(of, dw_mci_rockchip_match);

static int dw_mci_rockchip_probe(struct platform_device *pdev)
{
    const struct dw_mci_drv_data *drv_data;
    const struct of_device_id *match;
    int ret;
    bool use_rpm = true;

    if (!pdev->dev.of_node) {
        return -ENODEV;
    }

    if (!device_property_read_bool(&pdev->dev, "non-removable") && !device_property_read_bool(&pdev->dev, "cd-gpios")) {
        use_rpm = false;
    }

    match = of_match_node(dw_mci_rockchip_match, pdev->dev.of_node);
    drv_data = match->data;

    /*
     * increase rpm usage count in order to make
     * pm_runtime_force_resume calls rpm resume callback
     */
    pm_runtime_get_noresume(&pdev->dev);

    if (use_rpm) {
        pm_runtime_set_active(&pdev->dev);
        pm_runtime_enable(&pdev->dev);
        pm_runtime_set_autosuspend_delay(&pdev->dev, PM_AUTOSUSPEND_DELAY_COUNT);
        pm_runtime_use_autosuspend(&pdev->dev);
    }

    ret = dw_mci_pltfm_register(pdev, drv_data);
    if (ret) {
        if (use_rpm) {
            pm_runtime_disable(&pdev->dev);
            pm_runtime_set_suspended(&pdev->dev);
        }
        pm_runtime_put_noidle(&pdev->dev);
        return ret;
    }

    if (use_rpm) {
        pm_runtime_put_autosuspend(&pdev->dev);
    }

    return 0;
}

static int dw_mci_rockchip_remove(struct platform_device *pdev)
{
    pm_runtime_get_sync(&pdev->dev);
    pm_runtime_disable(&pdev->dev);
    pm_runtime_put_noidle(&pdev->dev);

    return dw_mci_pltfm_remove(pdev);
}

static const struct dev_pm_ops dw_mci_rockchip_dev_pm_ops = {
    SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
        SET_RUNTIME_PM_OPS(dw_mci_runtime_suspend, dw_mci_runtime_resume, NULL)};

static struct platform_driver dw_mci_rockchip_pltfm_driver = {
    .probe = dw_mci_rockchip_probe,
    .remove = dw_mci_rockchip_remove,
    .driver =
        {
            .name = "dwmmc_rockchip",
            .probe_type = PROBE_PREFER_ASYNCHRONOUS,
            .of_match_table = dw_mci_rockchip_match,
            .pm = &dw_mci_rockchip_dev_pm_ops,
        },
};

module_platform_driver(dw_mci_rockchip_pltfm_driver);

MODULE_AUTHOR("Addy Ke <addy.ke@rock-chips.com>");
MODULE_DESCRIPTION("Rockchip Specific DW-MSHC Driver Extension");
MODULE_ALIAS("platform:dwmmc_rockchip");
MODULE_LICENSE("GPL v2");