/*
 * Copyright (C) 2014 Texas Instruments Incorporated
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#define DSS_SUBSYS_NAME "PLL"

#include <linux/clk.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/regulator/consumer.h>
#include <linux/sched.h>

#include <video/omapfb_dss.h>

#include "dss.h"

#define PLL_CONTROL                     0x0000
#define PLL_STATUS                      0x0004
#define PLL_GO                          0x0008
#define PLL_CONFIGURATION1              0x000C
#define PLL_CONFIGURATION2              0x0010
#define PLL_CONFIGURATION3              0x0014
#define PLL_SSC_CONFIGURATION1          0x0018
#define PLL_SSC_CONFIGURATION2          0x001C
#define PLL_CONFIGURATION4              0x0020

static struct dss_pll *dss_plls[4];

int dss_pll_register(struct dss_pll *pll)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(dss_plls); ++i) {
                if (!dss_plls[i]) {
                        dss_plls[i] = pll;
                        return 0;
                }
        }

        return -EBUSY;
}

void dss_pll_unregister(struct dss_pll *pll)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(dss_plls); ++i) {
                if (dss_plls[i] == pll) {
                        dss_plls[i] = NULL;
                        return;
                }
        }
}

struct dss_pll *dss_pll_find(const char *name)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(dss_plls); ++i) {
                if (dss_plls[i] && strcmp(dss_plls[i]->name, name) == 0)
                        return dss_plls[i];
        }

        return NULL;
}

int dss_pll_enable(struct dss_pll *pll)
{
        int r;

        r = clk_prepare_enable(pll->clkin);
        if (r)
                return r;

        if (pll->regulator) {
                r = regulator_enable(pll->regulator);
                if (r)
                        goto err_reg;
        }

        r = pll->ops->enable(pll);
        if (r)
                goto err_enable;

        return 0;

err_enable:
        if (pll->regulator)
                regulator_disable(pll->regulator);
err_reg:
        clk_disable_unprepare(pll->clkin);
        return r;
}

void dss_pll_disable(struct dss_pll *pll)
{
        pll->ops->disable(pll);

        if (pll->regulator)
                regulator_disable(pll->regulator);

        clk_disable_unprepare(pll->clkin);

        memset(&pll->cinfo, 0, sizeof(pll->cinfo));
}

int dss_pll_set_config(struct dss_pll *pll, const struct dss_pll_clock_info *cinfo)
{
        int r;

        r = pll->ops->set_config(pll, cinfo);
        if (r)
                return r;

        pll->cinfo = *cinfo;

        return 0;
}

bool dss_pll_hsdiv_calc(const struct dss_pll *pll, unsigned long clkdco,
                unsigned long out_min, unsigned long out_max,
                dss_hsdiv_calc_func func, void *data)
{
        const struct dss_pll_hw *hw = pll->hw;
        int m, m_start, m_stop;
        unsigned long out;

        out_min = out_min ? out_min : 1;
        out_max = out_max ? out_max : ULONG_MAX;

        m_start = max(DIV_ROUND_UP(clkdco, out_max), 1ul);

        m_stop = min((unsigned)(clkdco / out_min), hw->mX_max);

        for (m = m_start; m <= m_stop; ++m) {
                out = clkdco / m;

                if (func(m, out, data))
                        return true;
        }

        return false;
}

bool dss_pll_calc(const struct dss_pll *pll, unsigned long clkin,
                unsigned long pll_min, unsigned long pll_max,
                dss_pll_calc_func func, void *data)
{
        const struct dss_pll_hw *hw = pll->hw;
        int n, n_start, n_stop;
        int m, m_start, m_stop;
        unsigned long fint, clkdco;
        unsigned long pll_hw_max;
        unsigned long fint_hw_min, fint_hw_max;

        pll_hw_max = hw->clkdco_max;

        fint_hw_min = hw->fint_min;
        fint_hw_max = hw->fint_max;

        n_start = max(DIV_ROUND_UP(clkin, fint_hw_max), 1ul);
        n_stop = min((unsigned)(clkin / fint_hw_min), hw->n_max);

        pll_max = pll_max ? pll_max : ULONG_MAX;

        for (n = n_start; n <= n_stop; ++n) {
                fint = clkin / n;

                m_start = max(DIV_ROUND_UP(DIV_ROUND_UP(pll_min, fint), 2),
                                1ul);
                m_stop = min3((unsigned)(pll_max / fint / 2),
                                (unsigned)(pll_hw_max / fint / 2),
                                hw->m_max);

                for (m = m_start; m <= m_stop; ++m) {
                        clkdco = 2 * m * fint;

                        if (func(n, m, fint, clkdco, data))
                                return true;
                }
        }

        return false;
}

static int wait_for_bit_change(void __iomem *reg, int bitnum, int value)
{
        unsigned long timeout;
        ktime_t wait;
        int t;

        /* first busyloop to see if the bit changes right away */
        t = 100;
        while (t-- > 0) {
                if (FLD_GET(readl_relaxed(reg), bitnum, bitnum) == value)
                        return value;
        }

        /* then loop for 500ms, sleeping for 1ms in between */
        timeout = jiffies + msecs_to_jiffies(500);
        while (time_before(jiffies, timeout)) {
                if (FLD_GET(readl_relaxed(reg), bitnum, bitnum) == value)
                        return value;

                wait = ns_to_ktime(1000 * 1000);
                set_current_state(TASK_UNINTERRUPTIBLE);
                schedule_hrtimeout(&wait, HRTIMER_MODE_REL);
        }

        return !value;
}

int dss_pll_wait_reset_done(struct dss_pll *pll)
{
        void __iomem *base = pll->base;

        if (wait_for_bit_change(base + PLL_STATUS, 0, 1) != 1)
                return -ETIMEDOUT;
        else
                return 0;
}

static int dss_wait_hsdiv_ack(struct dss_pll *pll, u32 hsdiv_ack_mask)
{
        int t = 100;

        while (t-- > 0) {
                u32 v = readl_relaxed(pll->base + PLL_STATUS);
                v &= hsdiv_ack_mask;
                if (v == hsdiv_ack_mask)
                        return 0;
        }

        return -ETIMEDOUT;
}

int dss_pll_write_config_type_a(struct dss_pll *pll,
                const struct dss_pll_clock_info *cinfo)
{
        const struct dss_pll_hw *hw = pll->hw;
        void __iomem *base = pll->base;
        int r = 0;
        u32 l;

        l = 0;
        if (hw->has_stopmode)
                l = FLD_MOD(l, 1, 0, 0);                /* PLL_STOPMODE */
        l = FLD_MOD(l, cinfo->n - 1, hw->n_msb, hw->n_lsb);     /* PLL_REGN */
        l = FLD_MOD(l, cinfo->m, hw->m_msb, hw->m_lsb);         /* PLL_REGM */
        /* M4 */
        l = FLD_MOD(l, cinfo->mX[0] ? cinfo->mX[0] - 1 : 0,
                        hw->mX_msb[0], hw->mX_lsb[0]);
        /* M5 */
        l = FLD_MOD(l, cinfo->mX[1] ? cinfo->mX[1] - 1 : 0,
                        hw->mX_msb[1], hw->mX_lsb[1]);
        writel_relaxed(l, base + PLL_CONFIGURATION1);

        l = 0;
        /* M6 */
        l = FLD_MOD(l, cinfo->mX[2] ? cinfo->mX[2] - 1 : 0,
                        hw->mX_msb[2], hw->mX_lsb[2]);
        /* M7 */
        l = FLD_MOD(l, cinfo->mX[3] ? cinfo->mX[3] - 1 : 0,
                        hw->mX_msb[3], hw->mX_lsb[3]);
        writel_relaxed(l, base + PLL_CONFIGURATION3);

        l = readl_relaxed(base + PLL_CONFIGURATION2);
        if (hw->has_freqsel) {
                u32 f = cinfo->fint < 1000000 ? 0x3 :
                        cinfo->fint < 1250000 ? 0x4 :
                        cinfo->fint < 1500000 ? 0x5 :
                        cinfo->fint < 1750000 ? 0x6 :
                        0x7;

                l = FLD_MOD(l, f, 4, 1);        /* PLL_FREQSEL */
        } else if (hw->has_selfreqdco) {
                u32 f = cinfo->clkdco < hw->clkdco_low ? 0x2 : 0x4;

                l = FLD_MOD(l, f, 3, 1);        /* PLL_SELFREQDCO */
        }
        l = FLD_MOD(l, 1, 13, 13);              /* PLL_REFEN */
        l = FLD_MOD(l, 0, 14, 14);              /* PHY_CLKINEN */
        l = FLD_MOD(l, 0, 16, 16);              /* M4_CLOCK_EN */
        l = FLD_MOD(l, 0, 18, 18);              /* M5_CLOCK_EN */
        l = FLD_MOD(l, 1, 20, 20);              /* HSDIVBYPASS */
        if (hw->has_refsel)
                l = FLD_MOD(l, 3, 22, 21);      /* REFSEL = sysclk */
        l = FLD_MOD(l, 0, 23, 23);              /* M6_CLOCK_EN */
        l = FLD_MOD(l, 0, 25, 25);              /* M7_CLOCK_EN */
        writel_relaxed(l, base + PLL_CONFIGURATION2);

        writel_relaxed(1, base + PLL_GO);       /* PLL_GO */

        if (wait_for_bit_change(base + PLL_GO, 0, 0) != 0) {
                DSSERR("DSS DPLL GO bit not going down.\n");
                r = -EIO;
                goto err;
        }

        if (wait_for_bit_change(base + PLL_STATUS, 1, 1) != 1) {
                DSSERR("cannot lock DSS DPLL\n");
                r = -EIO;
                goto err;
        }

        l = readl_relaxed(base + PLL_CONFIGURATION2);
        l = FLD_MOD(l, 1, 14, 14);                      /* PHY_CLKINEN */
        l = FLD_MOD(l, cinfo->mX[0] ? 1 : 0, 16, 16);   /* M4_CLOCK_EN */
        l = FLD_MOD(l, cinfo->mX[1] ? 1 : 0, 18, 18);   /* M5_CLOCK_EN */
        l = FLD_MOD(l, 0, 20, 20);                      /* HSDIVBYPASS */
        l = FLD_MOD(l, cinfo->mX[2] ? 1 : 0, 23, 23);   /* M6_CLOCK_EN */
        l = FLD_MOD(l, cinfo->mX[3] ? 1 : 0, 25, 25);   /* M7_CLOCK_EN */
        writel_relaxed(l, base + PLL_CONFIGURATION2);

        r = dss_wait_hsdiv_ack(pll,
                (cinfo->mX[0] ? BIT(7) : 0) |
                (cinfo->mX[1] ? BIT(8) : 0) |
                (cinfo->mX[2] ? BIT(10) : 0) |
                (cinfo->mX[3] ? BIT(11) : 0));
        if (r) {
                DSSERR("failed to enable HSDIV clocks\n");
                goto err;
        }

err:
        return r;
}

int dss_pll_write_config_type_b(struct dss_pll *pll,
                const struct dss_pll_clock_info *cinfo)
{
        const struct dss_pll_hw *hw = pll->hw;
        void __iomem *base = pll->base;
        u32 l;

        l = 0;
        l = FLD_MOD(l, cinfo->m, 20, 9);        /* PLL_REGM */
        l = FLD_MOD(l, cinfo->n - 1, 8, 1);     /* PLL_REGN */
        writel_relaxed(l, base + PLL_CONFIGURATION1);

        l = readl_relaxed(base + PLL_CONFIGURATION2);
        l = FLD_MOD(l, 0x0, 12, 12);    /* PLL_HIGHFREQ divide by 2 */
        l = FLD_MOD(l, 0x1, 13, 13);    /* PLL_REFEN */
        l = FLD_MOD(l, 0x0, 14, 14);    /* PHY_CLKINEN */
        if (hw->has_refsel)
                l = FLD_MOD(l, 0x3, 22, 21);    /* REFSEL = SYSCLK */

        /* PLL_SELFREQDCO */
        if (cinfo->clkdco > hw->clkdco_low)
                l = FLD_MOD(l, 0x4, 3, 1);
        else
                l = FLD_MOD(l, 0x2, 3, 1);
        writel_relaxed(l, base + PLL_CONFIGURATION2);

        l = readl_relaxed(base + PLL_CONFIGURATION3);
        l = FLD_MOD(l, cinfo->sd, 17, 10);      /* PLL_REGSD */
        writel_relaxed(l, base + PLL_CONFIGURATION3);

        l = readl_relaxed(base + PLL_CONFIGURATION4);
        l = FLD_MOD(l, cinfo->mX[0], 24, 18);   /* PLL_REGM2 */
        l = FLD_MOD(l, cinfo->mf, 17, 0);       /* PLL_REGM_F */
        writel_relaxed(l, base + PLL_CONFIGURATION4);

        writel_relaxed(1, base + PLL_GO);       /* PLL_GO */

        if (wait_for_bit_change(base + PLL_GO, 0, 0) != 0) {
                DSSERR("DSS DPLL GO bit not going down.\n");
                return -EIO;
        }

        if (wait_for_bit_change(base + PLL_STATUS, 1, 1) != 1) {
                DSSERR("cannot lock DSS DPLL\n");
                return -ETIMEDOUT;
        }

        return 0;
}