/*
 * Copyright (c) 2014-2016, NVIDIA CORPORATION. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 * Shamelessly ripped off from ChromeOS's gk20a/clk_pllg.c
 *
 */
#include "priv.h"
#include "gk20a.h"

#include <core/tegra.h>
#include <subdev/timer.h>

static const u8 _pl_to_div[] = {
/* PL:   0, 1, 2, 3, 4, 5, 6,  7,  8,  9, 10, 11, 12, 13, 14 */
/* p: */ 1, 2, 3, 4, 5, 6, 8, 10, 12, 16, 12, 16, 20, 24, 32,
};

static u32 pl_to_div(u32 pl)
{
        if (pl >= ARRAY_SIZE(_pl_to_div))
                return 1;

        return _pl_to_div[pl];
}

static u32 div_to_pl(u32 div)
{
        u32 pl;

        for (pl = 0; pl < ARRAY_SIZE(_pl_to_div) - 1; pl++) {
                if (_pl_to_div[pl] >= div)
                        return pl;
        }

        return ARRAY_SIZE(_pl_to_div) - 1;
}

static const struct gk20a_clk_pllg_params gk20a_pllg_params = {
        .min_vco = 1000000, .max_vco = 2064000,
        .min_u = 12000, .max_u = 38000,
        .min_m = 1, .max_m = 255,
        .min_n = 8, .max_n = 255,
        .min_pl = 1, .max_pl = 32,
};

void
gk20a_pllg_read_mnp(struct gk20a_clk *clk, struct gk20a_pll *pll)
{
        struct nvkm_device *device = clk->base.subdev.device;
        u32 val;

        val = nvkm_rd32(device, GPCPLL_COEFF);
        pll->m = (val >> GPCPLL_COEFF_M_SHIFT) & MASK(GPCPLL_COEFF_M_WIDTH);
        pll->n = (val >> GPCPLL_COEFF_N_SHIFT) & MASK(GPCPLL_COEFF_N_WIDTH);
        pll->pl = (val >> GPCPLL_COEFF_P_SHIFT) & MASK(GPCPLL_COEFF_P_WIDTH);
}

void
gk20a_pllg_write_mnp(struct gk20a_clk *clk, const struct gk20a_pll *pll)
{
        struct nvkm_device *device = clk->base.subdev.device;
        u32 val;

        val = (pll->m & MASK(GPCPLL_COEFF_M_WIDTH)) << GPCPLL_COEFF_M_SHIFT;
        val |= (pll->n & MASK(GPCPLL_COEFF_N_WIDTH)) << GPCPLL_COEFF_N_SHIFT;
        val |= (pll->pl & MASK(GPCPLL_COEFF_P_WIDTH)) << GPCPLL_COEFF_P_SHIFT;
        nvkm_wr32(device, GPCPLL_COEFF, val);
}

u32
gk20a_pllg_calc_rate(struct gk20a_clk *clk, struct gk20a_pll *pll)
{
        u32 rate;
        u32 divider;

        rate = clk->parent_rate * pll->n;
        divider = pll->m * clk->pl_to_div(pll->pl);

        return rate / divider / 2;
}

int
gk20a_pllg_calc_mnp(struct gk20a_clk *clk, unsigned long rate,
                    struct gk20a_pll *pll)
{
        struct nvkm_subdev *subdev = &clk->base.subdev;
        u32 target_clk_f, ref_clk_f, target_freq;
        u32 min_vco_f, max_vco_f;
        u32 low_pl, high_pl, best_pl;
        u32 target_vco_f;
        u32 best_m, best_n;
        u32 best_delta = ~0;
        u32 pl;

        target_clk_f = rate * 2 / KHZ;
        ref_clk_f = clk->parent_rate / KHZ;

        target_vco_f = target_clk_f + target_clk_f / 50;
        max_vco_f = max(clk->params->max_vco, target_vco_f);
        min_vco_f = clk->params->min_vco;
        best_m = clk->params->max_m;
        best_n = clk->params->min_n;
        best_pl = clk->params->min_pl;

        /* min_pl <= high_pl <= max_pl */
        high_pl = (max_vco_f + target_vco_f - 1) / target_vco_f;
        high_pl = min(high_pl, clk->params->max_pl);
        high_pl = max(high_pl, clk->params->min_pl);
        high_pl = clk->div_to_pl(high_pl);

        /* min_pl <= low_pl <= max_pl */
        low_pl = min_vco_f / target_vco_f;
        low_pl = min(low_pl, clk->params->max_pl);
        low_pl = max(low_pl, clk->params->min_pl);
        low_pl = clk->div_to_pl(low_pl);

        nvkm_debug(subdev, "low_PL %d(div%d), high_PL %d(div%d)", low_pl,
                   clk->pl_to_div(low_pl), high_pl, clk->pl_to_div(high_pl));

        /* Select lowest possible VCO */
        for (pl = low_pl; pl <= high_pl; pl++) {
                u32 m, n, n2;

                target_vco_f = target_clk_f * clk->pl_to_div(pl);

                for (m = clk->params->min_m; m <= clk->params->max_m; m++) {
                        u32 u_f = ref_clk_f / m;

                        if (u_f < clk->params->min_u)
                                break;
                        if (u_f > clk->params->max_u)
                                continue;

                        n = (target_vco_f * m) / ref_clk_f;
                        n2 = ((target_vco_f * m) + (ref_clk_f - 1)) / ref_clk_f;

                        if (n > clk->params->max_n)
                                break;

                        for (; n <= n2; n++) {
                                u32 vco_f;

                                if (n < clk->params->min_n)
                                        continue;
                                if (n > clk->params->max_n)
                                        break;

                                vco_f = ref_clk_f * n / m;

                                if (vco_f >= min_vco_f && vco_f <= max_vco_f) {
                                        u32 delta, lwv;

                                        lwv = (vco_f + (clk->pl_to_div(pl) / 2))
                                                / clk->pl_to_div(pl);
                                        delta = abs(lwv - target_clk_f);

                                        if (delta < best_delta) {
                                                best_delta = delta;
                                                best_m = m;
                                                best_n = n;
                                                best_pl = pl;

                                                if (best_delta == 0)
                                                        goto found_match;
                                        }
                                }
                        }
                }
        }

found_match:
        WARN_ON(best_delta == ~0);

        if (best_delta != 0)
                nvkm_debug(subdev,
                           "no best match for target @ %dMHz on gpc_pll",
                           target_clk_f / KHZ);

        pll->m = best_m;
        pll->n = best_n;
        pll->pl = best_pl;

        target_freq = gk20a_pllg_calc_rate(clk, pll);

        nvkm_debug(subdev,
                   "actual target freq %d KHz, M %d, N %d, PL %d(div%d)\n",
                   target_freq / KHZ, pll->m, pll->n, pll->pl,
                   clk->pl_to_div(pll->pl));
        return 0;
}

static int
gk20a_pllg_slide(struct gk20a_clk *clk, u32 n)
{
        struct nvkm_subdev *subdev = &clk->base.subdev;
        struct nvkm_device *device = subdev->device;
        struct gk20a_pll pll;
        int ret = 0;

        /* get old coefficients */
        gk20a_pllg_read_mnp(clk, &pll);
        /* do nothing if NDIV is the same */
        if (n == pll.n)
                return 0;

        /* pll slowdown mode */
        nvkm_mask(device, GPCPLL_NDIV_SLOWDOWN,
                BIT(GPCPLL_NDIV_SLOWDOWN_SLOWDOWN_USING_PLL_SHIFT),
                BIT(GPCPLL_NDIV_SLOWDOWN_SLOWDOWN_USING_PLL_SHIFT));

        /* new ndiv ready for ramp */
        pll.n = n;
        udelay(1);
        gk20a_pllg_write_mnp(clk, &pll);

        /* dynamic ramp to new ndiv */
        udelay(1);
        nvkm_mask(device, GPCPLL_NDIV_SLOWDOWN,
                  BIT(GPCPLL_NDIV_SLOWDOWN_EN_DYNRAMP_SHIFT),
                  BIT(GPCPLL_NDIV_SLOWDOWN_EN_DYNRAMP_SHIFT));

        /* wait for ramping to complete */
        if (nvkm_wait_usec(device, 500, GPC_BCAST_NDIV_SLOWDOWN_DEBUG,
                GPC_BCAST_NDIV_SLOWDOWN_DEBUG_PLL_DYNRAMP_DONE_SYNCED_MASK,
                GPC_BCAST_NDIV_SLOWDOWN_DEBUG_PLL_DYNRAMP_DONE_SYNCED_MASK) < 0)
                ret = -ETIMEDOUT;

        /* exit slowdown mode */
        nvkm_mask(device, GPCPLL_NDIV_SLOWDOWN,
                BIT(GPCPLL_NDIV_SLOWDOWN_SLOWDOWN_USING_PLL_SHIFT) |
                BIT(GPCPLL_NDIV_SLOWDOWN_EN_DYNRAMP_SHIFT), 0);
        nvkm_rd32(device, GPCPLL_NDIV_SLOWDOWN);

        return ret;
}

static int
gk20a_pllg_enable(struct gk20a_clk *clk)
{
        struct nvkm_device *device = clk->base.subdev.device;
        u32 val;

        nvkm_mask(device, GPCPLL_CFG, GPCPLL_CFG_ENABLE, GPCPLL_CFG_ENABLE);
        nvkm_rd32(device, GPCPLL_CFG);

        /* enable lock detection */
        val = nvkm_rd32(device, GPCPLL_CFG);
        if (val & GPCPLL_CFG_LOCK_DET_OFF) {
                val &= ~GPCPLL_CFG_LOCK_DET_OFF;
                nvkm_wr32(device, GPCPLL_CFG, val);
        }

        /* wait for lock */
        if (nvkm_wait_usec(device, 300, GPCPLL_CFG, GPCPLL_CFG_LOCK,
                           GPCPLL_CFG_LOCK) < 0)
                return -ETIMEDOUT;

        /* switch to VCO mode */
        nvkm_mask(device, SEL_VCO, BIT(SEL_VCO_GPC2CLK_OUT_SHIFT),
                BIT(SEL_VCO_GPC2CLK_OUT_SHIFT));

        return 0;
}

static void
gk20a_pllg_disable(struct gk20a_clk *clk)
{
        struct nvkm_device *device = clk->base.subdev.device;

        /* put PLL in bypass before disabling it */
        nvkm_mask(device, SEL_VCO, BIT(SEL_VCO_GPC2CLK_OUT_SHIFT), 0);

        nvkm_mask(device, GPCPLL_CFG, GPCPLL_CFG_ENABLE, 0);
        nvkm_rd32(device, GPCPLL_CFG);
}

static int
gk20a_pllg_program_mnp(struct gk20a_clk *clk, const struct gk20a_pll *pll)
{
        struct nvkm_subdev *subdev = &clk->base.subdev;
        struct nvkm_device *device = subdev->device;
        struct gk20a_pll cur_pll;
        int ret;

        gk20a_pllg_read_mnp(clk, &cur_pll);

        /* split VCO-to-bypass jump in half by setting out divider 1:2 */
        nvkm_mask(device, GPC2CLK_OUT, GPC2CLK_OUT_VCODIV_MASK,
                  GPC2CLK_OUT_VCODIV2 << GPC2CLK_OUT_VCODIV_SHIFT);
        /* Intentional 2nd write to assure linear divider operation */
        nvkm_mask(device, GPC2CLK_OUT, GPC2CLK_OUT_VCODIV_MASK,
                  GPC2CLK_OUT_VCODIV2 << GPC2CLK_OUT_VCODIV_SHIFT);
        nvkm_rd32(device, GPC2CLK_OUT);
        udelay(2);

        gk20a_pllg_disable(clk);

        gk20a_pllg_write_mnp(clk, pll);

        ret = gk20a_pllg_enable(clk);
        if (ret)
                return ret;

        /* restore out divider 1:1 */
        udelay(2);
        nvkm_mask(device, GPC2CLK_OUT, GPC2CLK_OUT_VCODIV_MASK,
                  GPC2CLK_OUT_VCODIV1 << GPC2CLK_OUT_VCODIV_SHIFT);
        /* Intentional 2nd write to assure linear divider operation */
        nvkm_mask(device, GPC2CLK_OUT, GPC2CLK_OUT_VCODIV_MASK,
                  GPC2CLK_OUT_VCODIV1 << GPC2CLK_OUT_VCODIV_SHIFT);
        nvkm_rd32(device, GPC2CLK_OUT);

        return 0;
}

static int
gk20a_pllg_program_mnp_slide(struct gk20a_clk *clk, const struct gk20a_pll *pll)
{
        struct gk20a_pll cur_pll;
        int ret;

        if (gk20a_pllg_is_enabled(clk)) {
                gk20a_pllg_read_mnp(clk, &cur_pll);

                /* just do NDIV slide if there is no change to M and PL */
                if (pll->m == cur_pll.m && pll->pl == cur_pll.pl)
                        return gk20a_pllg_slide(clk, pll->n);

                /* slide down to current NDIV_LO */
                cur_pll.n = gk20a_pllg_n_lo(clk, &cur_pll);
                ret = gk20a_pllg_slide(clk, cur_pll.n);
                if (ret)
                        return ret;
        }

        /* program MNP with the new clock parameters and new NDIV_LO */
        cur_pll = *pll;
        cur_pll.n = gk20a_pllg_n_lo(clk, &cur_pll);
        ret = gk20a_pllg_program_mnp(clk, &cur_pll);
        if (ret)
                return ret;

        /* slide up to new NDIV */
        return gk20a_pllg_slide(clk, pll->n);
}

static struct nvkm_pstate
gk20a_pstates[] = {
        {
                .base = {
                        .domain[nv_clk_src_gpc] = 72000,
                        .voltage = 0,
                },
        },
        {
                .base = {
                        .domain[nv_clk_src_gpc] = 108000,
                        .voltage = 1,
                },
        },
        {
                .base = {
                        .domain[nv_clk_src_gpc] = 180000,
                        .voltage = 2,
                },
        },
        {
                .base = {
                        .domain[nv_clk_src_gpc] = 252000,
                        .voltage = 3,
                },
        },
        {
                .base = {
                        .domain[nv_clk_src_gpc] = 324000,
                        .voltage = 4,
                },
        },
        {
                .base = {
                        .domain[nv_clk_src_gpc] = 396000,
                        .voltage = 5,
                },
        },
        {
                .base = {
                        .domain[nv_clk_src_gpc] = 468000,
                        .voltage = 6,
                },
        },
        {
                .base = {
                        .domain[nv_clk_src_gpc] = 540000,
                        .voltage = 7,
                },
        },
        {
                .base = {
                        .domain[nv_clk_src_gpc] = 612000,
                        .voltage = 8,
                },
        },
        {
                .base = {
                        .domain[nv_clk_src_gpc] = 648000,
                        .voltage = 9,
                },
        },
        {
                .base = {
                        .domain[nv_clk_src_gpc] = 684000,
                        .voltage = 10,
                },
        },
        {
                .base = {
                        .domain[nv_clk_src_gpc] = 708000,
                        .voltage = 11,
                },
        },
        {
                .base = {
                        .domain[nv_clk_src_gpc] = 756000,
                        .voltage = 12,
                },
        },
        {
                .base = {
                        .domain[nv_clk_src_gpc] = 804000,
                        .voltage = 13,
                },
        },
        {
                .base = {
                        .domain[nv_clk_src_gpc] = 852000,
                        .voltage = 14,
                },
        },
};

int
gk20a_clk_read(struct nvkm_clk *base, enum nv_clk_src src)
{
        struct gk20a_clk *clk = gk20a_clk(base);
        struct nvkm_subdev *subdev = &clk->base.subdev;
        struct nvkm_device *device = subdev->device;
        struct gk20a_pll pll;

        switch (src) {
        case nv_clk_src_crystal:
                return device->crystal;
        case nv_clk_src_gpc:
                gk20a_pllg_read_mnp(clk, &pll);
                return gk20a_pllg_calc_rate(clk, &pll) / GK20A_CLK_GPC_MDIV;
        default:
                nvkm_error(subdev, "invalid clock source %d\n", src);
                return -EINVAL;
        }
}

int
gk20a_clk_calc(struct nvkm_clk *base, struct nvkm_cstate *cstate)
{
        struct gk20a_clk *clk = gk20a_clk(base);

        return gk20a_pllg_calc_mnp(clk, cstate->domain[nv_clk_src_gpc] *
                                         GK20A_CLK_GPC_MDIV, &clk->pll);
}

int
gk20a_clk_prog(struct nvkm_clk *base)
{
        struct gk20a_clk *clk = gk20a_clk(base);
        int ret;

        ret = gk20a_pllg_program_mnp_slide(clk, &clk->pll);
        if (ret)
                ret = gk20a_pllg_program_mnp(clk, &clk->pll);

        return ret;
}

void
gk20a_clk_tidy(struct nvkm_clk *base)
{
}

int
gk20a_clk_setup_slide(struct gk20a_clk *clk)
{
        struct nvkm_subdev *subdev = &clk->base.subdev;
        struct nvkm_device *device = subdev->device;
        u32 step_a, step_b;

        switch (clk->parent_rate) {
        case 12000000:
        case 12800000:
        case 13000000:
                step_a = 0x2b;
                step_b = 0x0b;
                break;
        case 19200000:
                step_a = 0x12;
                step_b = 0x08;
                break;
        case 38400000:
                step_a = 0x04;
                step_b = 0x05;
                break;
        default:
                nvkm_error(subdev, "invalid parent clock rate %u KHz",
                           clk->parent_rate / KHZ);
                return -EINVAL;
        }

        nvkm_mask(device, GPCPLL_CFG2, 0xff << GPCPLL_CFG2_PLL_STEPA_SHIFT,
                step_a << GPCPLL_CFG2_PLL_STEPA_SHIFT);
        nvkm_mask(device, GPCPLL_CFG3, 0xff << GPCPLL_CFG3_PLL_STEPB_SHIFT,
                step_b << GPCPLL_CFG3_PLL_STEPB_SHIFT);

        return 0;
}

void
gk20a_clk_fini(struct nvkm_clk *base)
{
        struct nvkm_device *device = base->subdev.device;
        struct gk20a_clk *clk = gk20a_clk(base);

        /* slide to VCO min */
        if (gk20a_pllg_is_enabled(clk)) {
                struct gk20a_pll pll;
                u32 n_lo;

                gk20a_pllg_read_mnp(clk, &pll);
                n_lo = gk20a_pllg_n_lo(clk, &pll);
                gk20a_pllg_slide(clk, n_lo);
        }

        gk20a_pllg_disable(clk);

        /* set IDDQ */
        nvkm_mask(device, GPCPLL_CFG, GPCPLL_CFG_IDDQ, 1);
}

static int
gk20a_clk_init(struct nvkm_clk *base)
{
        struct gk20a_clk *clk = gk20a_clk(base);
        struct nvkm_subdev *subdev = &clk->base.subdev;
        struct nvkm_device *device = subdev->device;
        int ret;

        /* get out from IDDQ */
        nvkm_mask(device, GPCPLL_CFG, GPCPLL_CFG_IDDQ, 0);
        nvkm_rd32(device, GPCPLL_CFG);
        udelay(5);

        nvkm_mask(device, GPC2CLK_OUT, GPC2CLK_OUT_INIT_MASK,
                  GPC2CLK_OUT_INIT_VAL);

        ret = gk20a_clk_setup_slide(clk);
        if (ret)
                return ret;

        /* Start with lowest frequency */
        base->func->calc(base, &base->func->pstates[0].base);
        ret = base->func->prog(&clk->base);
        if (ret) {
                nvkm_error(subdev, "cannot initialize clock\n");
                return ret;
        }

        return 0;
}

static const struct nvkm_clk_func
gk20a_clk = {
        .init = gk20a_clk_init,
        .fini = gk20a_clk_fini,
        .read = gk20a_clk_read,
        .calc = gk20a_clk_calc,
        .prog = gk20a_clk_prog,
        .tidy = gk20a_clk_tidy,
        .pstates = gk20a_pstates,
        .nr_pstates = ARRAY_SIZE(gk20a_pstates),
        .domains = {
                { nv_clk_src_crystal, 0xff },
                { nv_clk_src_gpc, 0xff, 0, "core", GK20A_CLK_GPC_MDIV },
                { nv_clk_src_max }
        }
};

int
gk20a_clk_ctor(struct nvkm_device *device, enum nvkm_subdev_type type, int inst,
               const struct nvkm_clk_func *func, const struct gk20a_clk_pllg_params *params,
               struct gk20a_clk *clk)
{
        struct nvkm_device_tegra *tdev = device->func->tegra(device);
        int ret;
        int i;

        /* Finish initializing the pstates */
        for (i = 0; i < func->nr_pstates; i++) {
                INIT_LIST_HEAD(&func->pstates[i].list);
                func->pstates[i].pstate = i + 1;
        }

        clk->params = params;
        clk->parent_rate = clk_get_rate(tdev->clk);

        ret = nvkm_clk_ctor(func, device, type, inst, true, &clk->base);
        if (ret)
                return ret;

        nvkm_debug(&clk->base.subdev, "parent clock rate: %d Khz\n",
                   clk->parent_rate / KHZ);

        return 0;
}

int
gk20a_clk_new(struct nvkm_device *device, enum nvkm_subdev_type type, int inst,
              struct nvkm_clk **pclk)
{
        struct gk20a_clk *clk;
        int ret;

        clk = kzalloc(sizeof(*clk), GFP_KERNEL);
        if (!clk)
                return -ENOMEM;
        *pclk = &clk->base;

        ret = gk20a_clk_ctor(device, type, inst, &gk20a_clk, &gk20a_pllg_params, clk);

        clk->pl_to_div = pl_to_div;
        clk->div_to_pl = div_to_pl;
        return ret;
}