root/drivers/media/i2c/ccs-pll.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * drivers/media/i2c/ccs-pll.c
 *
 * Generic MIPI CCS/SMIA/SMIA++ PLL calculator
 *
 * Copyright (C) 2020 Intel Corporation
 * Copyright (C) 2011--2012 Nokia Corporation
 * Contact: Sakari Ailus <sakari.ailus@linux.intel.com>
 */

#include <linux/device.h>
#include <linux/gcd.h>
#include <linux/lcm.h>
#include <linux/module.h>

#include "ccs-pll.h"

/* Return an even number or one. */
static inline u32 clk_div_even(u32 a)
{
        return max_t(u32, 1, a & ~1);
}

/* Return an even number or one. */
static inline u32 clk_div_even_up(u32 a)
{
        if (a == 1)
                return 1;
        return (a + 1) & ~1;
}

static inline u32 is_one_or_even(u32 a)
{
        if (a == 1)
                return 1;
        if (a & 1)
                return 0;

        return 1;
}

static inline u32 one_or_more(u32 a)
{
        return a ?: 1;
}

static int bounds_check(struct device *dev, u32 val,
                        u32 min, u32 max, const char *prefix,
                        char *str)
{
        if (val >= min && val <= max)
                return 0;

        dev_dbg(dev, "%s_%s out of bounds: %d (%d--%d)\n", prefix,
                str, val, min, max);

        return -EINVAL;
}

#define PLL_OP 1
#define PLL_VT 2

static const char *pll_string(unsigned int which)
{
        switch (which) {
        case PLL_OP:
                return "op";
        case PLL_VT:
                return "vt";
        }

        return NULL;
}

#define PLL_FL(f) CCS_PLL_FLAG_##f

static void print_pll(struct device *dev, const struct ccs_pll *pll)
{
        const struct {
                const struct ccs_pll_branch_fr *fr;
                const struct ccs_pll_branch_bk *bk;
                unsigned int which;
        } branches[] = {
                { &pll->vt_fr, &pll->vt_bk, PLL_VT },
                { &pll->op_fr, &pll->op_bk, PLL_OP }
        }, *br;
        unsigned int i;

        dev_dbg(dev, "ext_clk_freq_hz\t\t%u\n", pll->ext_clk_freq_hz);

        for (i = 0, br = branches; i < ARRAY_SIZE(branches); i++, br++) {
                const char *s = pll_string(br->which);

                if (pll->flags & CCS_PLL_FLAG_DUAL_PLL ||
                    br->which == PLL_VT) {
                        dev_dbg(dev, "%s_pre_pll_clk_div\t\t%u\n",  s,
                                br->fr->pre_pll_clk_div);
                        dev_dbg(dev, "%s_pll_multiplier\t\t%u\n",  s,
                                br->fr->pll_multiplier);

                        dev_dbg(dev, "%s_pll_ip_clk_freq_hz\t%u\n", s,
                                br->fr->pll_ip_clk_freq_hz);
                        dev_dbg(dev, "%s_pll_op_clk_freq_hz\t%u\n", s,
                                br->fr->pll_op_clk_freq_hz);
                }

                if (!(pll->flags & CCS_PLL_FLAG_NO_OP_CLOCKS) ||
                    br->which == PLL_VT) {
                        dev_dbg(dev, "%s_sys_clk_div\t\t%u\n",  s,
                                br->bk->sys_clk_div);
                        dev_dbg(dev, "%s_pix_clk_div\t\t%u\n", s,
                                br->bk->pix_clk_div);

                        dev_dbg(dev, "%s_sys_clk_freq_hz\t%u\n", s,
                                br->bk->sys_clk_freq_hz);
                        dev_dbg(dev, "%s_pix_clk_freq_hz\t%u\n", s,
                                br->bk->pix_clk_freq_hz);
                }
        }

        dev_dbg(dev, "pixel rate in pixel array:\t%u\n",
                pll->pixel_rate_pixel_array);
        dev_dbg(dev, "pixel rate on CSI-2 bus:\t%u\n",
                pll->pixel_rate_csi);
}

static void print_pll_flags(struct device *dev, struct ccs_pll *pll)
{
        dev_dbg(dev, "PLL flags%s%s%s%s%s%s%s%s%s%s%s\n",
                pll->flags & PLL_FL(OP_PIX_CLOCK_PER_LANE) ? " op-pix-clock-per-lane" : "",
                pll->flags & PLL_FL(EVEN_PLL_MULTIPLIER) ? " even-pll-multiplier" : "",
                pll->flags & PLL_FL(NO_OP_CLOCKS) ? " no-op-clocks" : "",
                pll->flags & PLL_FL(LANE_SPEED_MODEL) ? " lane-speed" : "",
                pll->flags & PLL_FL(EXT_IP_PLL_DIVIDER) ?
                " ext-ip-pll-divider" : "",
                pll->flags & PLL_FL(FLEXIBLE_OP_PIX_CLK_DIV) ?
                " flexible-op-pix-div" : "",
                pll->flags & PLL_FL(FIFO_DERATING) ? " fifo-derating" : "",
                pll->flags & PLL_FL(FIFO_OVERRATING) ? " fifo-overrating" : "",
                pll->flags & PLL_FL(DUAL_PLL) ? " dual-pll" : "",
                pll->flags & PLL_FL(OP_SYS_DDR) ? " op-sys-ddr" : "",
                pll->flags & PLL_FL(OP_PIX_DDR) ? " op-pix-ddr" : "");
}

static u32 op_sys_ddr(u32 flags)
{
        return flags & CCS_PLL_FLAG_OP_SYS_DDR ? 1 : 0;
}

static u32 op_pix_ddr(u32 flags)
{
        return flags & CCS_PLL_FLAG_OP_PIX_DDR ? 1 : 0;
}

static int check_fr_bounds(struct device *dev,
                           const struct ccs_pll_limits *lim,
                           const struct ccs_pll *pll, unsigned int which)
{
        const struct ccs_pll_branch_limits_fr *lim_fr;
        const struct ccs_pll_branch_fr *pll_fr;
        const char *s = pll_string(which);
        int rval;

        if (which == PLL_OP) {
                lim_fr = &lim->op_fr;
                pll_fr = &pll->op_fr;
        } else {
                lim_fr = &lim->vt_fr;
                pll_fr = &pll->vt_fr;
        }

        rval = bounds_check(dev, pll_fr->pre_pll_clk_div,
                            lim_fr->min_pre_pll_clk_div,
                            lim_fr->max_pre_pll_clk_div, s, "pre_pll_clk_div");

        if (!rval)
                rval = bounds_check(dev, pll_fr->pll_ip_clk_freq_hz,
                                    lim_fr->min_pll_ip_clk_freq_hz,
                                    lim_fr->max_pll_ip_clk_freq_hz,
                                    s, "pll_ip_clk_freq_hz");
        if (!rval)
                rval = bounds_check(dev, pll_fr->pll_multiplier,
                                    lim_fr->min_pll_multiplier,
                                    lim_fr->max_pll_multiplier,
                                    s, "pll_multiplier");
        if (!rval)
                rval = bounds_check(dev, pll_fr->pll_op_clk_freq_hz,
                                    lim_fr->min_pll_op_clk_freq_hz,
                                    lim_fr->max_pll_op_clk_freq_hz,
                                    s, "pll_op_clk_freq_hz");

        return rval;
}

static int check_bk_bounds(struct device *dev,
                           const struct ccs_pll_limits *lim,
                           const struct ccs_pll *pll, unsigned int which)
{
        const struct ccs_pll_branch_limits_bk *lim_bk;
        const struct ccs_pll_branch_bk *pll_bk;
        const char *s = pll_string(which);
        int rval;

        if (which == PLL_OP) {
                if (pll->flags & CCS_PLL_FLAG_NO_OP_CLOCKS)
                        return 0;

                lim_bk = &lim->op_bk;
                pll_bk = &pll->op_bk;
        } else {
                lim_bk = &lim->vt_bk;
                pll_bk = &pll->vt_bk;
        }

        rval = bounds_check(dev, pll_bk->sys_clk_div,
                            lim_bk->min_sys_clk_div,
                            lim_bk->max_sys_clk_div, s, "op_sys_clk_div");
        if (!rval)
                rval = bounds_check(dev, pll_bk->sys_clk_freq_hz,
                                    lim_bk->min_sys_clk_freq_hz,
                                    lim_bk->max_sys_clk_freq_hz,
                                    s, "sys_clk_freq_hz");
        if (!rval)
                rval = bounds_check(dev, pll_bk->sys_clk_div,
                                    lim_bk->min_sys_clk_div,
                                    lim_bk->max_sys_clk_div,
                                    s, "sys_clk_div");
        if (!rval)
                rval = bounds_check(dev, pll_bk->pix_clk_freq_hz,
                                    lim_bk->min_pix_clk_freq_hz,
                                    lim_bk->max_pix_clk_freq_hz,
                                    s, "pix_clk_freq_hz");

        return rval;
}

static int check_ext_bounds(struct device *dev, const struct ccs_pll *pll)
{
        if (!(pll->flags & CCS_PLL_FLAG_FIFO_DERATING) &&
            pll->pixel_rate_pixel_array > pll->pixel_rate_csi) {
                dev_dbg(dev, "device does not support derating\n");
                return -EINVAL;
        }

        if (!(pll->flags & CCS_PLL_FLAG_FIFO_OVERRATING) &&
            pll->pixel_rate_pixel_array < pll->pixel_rate_csi) {
                dev_dbg(dev, "device does not support overrating\n");
                return -EINVAL;
        }

        return 0;
}

static void
ccs_pll_find_vt_sys_div(struct device *dev, const struct ccs_pll_limits *lim,
                        struct ccs_pll *pll, struct ccs_pll_branch_fr *pll_fr,
                        u16 min_vt_div, u16 max_vt_div,
                        u16 *min_sys_div, u16 *max_sys_div)
{
        /*
         * Find limits for sys_clk_div. Not all values are possible with all
         * values of pix_clk_div.
         */
        *min_sys_div = lim->vt_bk.min_sys_clk_div;
        dev_dbg(dev, "min_sys_div: %u\n", *min_sys_div);
        *min_sys_div = max_t(u16, *min_sys_div,
                             DIV_ROUND_UP(min_vt_div,
                                          lim->vt_bk.max_pix_clk_div));
        dev_dbg(dev, "min_sys_div: max_vt_pix_clk_div: %u\n", *min_sys_div);
        *min_sys_div = max_t(u16, *min_sys_div,
                             pll_fr->pll_op_clk_freq_hz
                             / lim->vt_bk.max_sys_clk_freq_hz);
        dev_dbg(dev, "min_sys_div: max_pll_op_clk_freq_hz: %u\n", *min_sys_div);
        *min_sys_div = clk_div_even_up(*min_sys_div);
        dev_dbg(dev, "min_sys_div: one or even: %u\n", *min_sys_div);

        *max_sys_div = lim->vt_bk.max_sys_clk_div;
        dev_dbg(dev, "max_sys_div: %u\n", *max_sys_div);
        *max_sys_div = min_t(u16, *max_sys_div,
                             DIV_ROUND_UP(max_vt_div,
                                          lim->vt_bk.min_pix_clk_div));
        dev_dbg(dev, "max_sys_div: min_vt_pix_clk_div: %u\n", *max_sys_div);
        *max_sys_div = min_t(u16, *max_sys_div,
                             DIV_ROUND_UP(pll_fr->pll_op_clk_freq_hz,
                                          lim->vt_bk.min_pix_clk_freq_hz));
        dev_dbg(dev, "max_sys_div: min_vt_pix_clk_freq_hz: %u\n", *max_sys_div);
}

#define CPHY_CONST              7
#define DPHY_CONST              16
#define PHY_CONST_DIV           16

static inline int
__ccs_pll_calculate_vt_tree(struct device *dev,
                            const struct ccs_pll_limits *lim,
                            struct ccs_pll *pll, u32 mul, u32 div)
{
        const struct ccs_pll_branch_limits_fr *lim_fr = &lim->vt_fr;
        const struct ccs_pll_branch_limits_bk *lim_bk = &lim->vt_bk;
        struct ccs_pll_branch_fr *pll_fr = &pll->vt_fr;
        struct ccs_pll_branch_bk *pll_bk = &pll->vt_bk;
        u32 more_mul;
        u16 best_pix_div = SHRT_MAX >> 1, best_div = lim_bk->max_sys_clk_div;
        u16 vt_div, min_sys_div, max_sys_div, sys_div;

        pll_fr->pll_ip_clk_freq_hz =
                pll->ext_clk_freq_hz / pll_fr->pre_pll_clk_div;

        dev_dbg(dev, "vt_pll_ip_clk_freq_hz %u\n", pll_fr->pll_ip_clk_freq_hz);

        more_mul = one_or_more(DIV_ROUND_UP(lim_fr->min_pll_op_clk_freq_hz,
                                            pll_fr->pll_ip_clk_freq_hz * mul));

        dev_dbg(dev, "more_mul: %u\n", more_mul);
        more_mul *= DIV_ROUND_UP(lim_fr->min_pll_multiplier, mul * more_mul);
        dev_dbg(dev, "more_mul2: %u\n", more_mul);

        if (pll->flags & CCS_PLL_FLAG_EVEN_PLL_MULTIPLIER &&
            (mul & 1) && (more_mul & 1))
                more_mul <<= 1;

        pll_fr->pll_multiplier = mul * more_mul;
        if (pll_fr->pll_multiplier > lim_fr->max_pll_multiplier) {
                dev_dbg(dev, "pll multiplier %u too high\n",
                        pll_fr->pll_multiplier);
                return -EINVAL;
        }

        pll_fr->pll_op_clk_freq_hz =
                pll_fr->pll_ip_clk_freq_hz * pll_fr->pll_multiplier;
        if (pll_fr->pll_op_clk_freq_hz > lim_fr->max_pll_op_clk_freq_hz) {
                dev_dbg(dev, "too high OP clock %u\n",
                        pll_fr->pll_op_clk_freq_hz);
                return -EINVAL;
        }

        vt_div = div * more_mul;

        ccs_pll_find_vt_sys_div(dev, lim, pll, pll_fr, vt_div, vt_div,
                                &min_sys_div, &max_sys_div);

        max_sys_div = (vt_div & 1) ? 1 : max_sys_div;

        dev_dbg(dev, "vt min/max_sys_div: %u,%u\n", min_sys_div, max_sys_div);

        for (sys_div = min_sys_div; sys_div <= max_sys_div;
             sys_div += 2 - (sys_div & 1)) {
                u16 pix_div;

                if (vt_div % sys_div)
                        continue;

                pix_div = vt_div / sys_div;

                if (pix_div < lim_bk->min_pix_clk_div ||
                    pix_div > lim_bk->max_pix_clk_div) {
                        dev_dbg(dev,
                                "pix_div %u too small or too big (%u--%u)\n",
                                pix_div,
                                lim_bk->min_pix_clk_div,
                                lim_bk->max_pix_clk_div);
                        continue;
                }

                dev_dbg(dev, "sys/pix/best_pix: %u,%u,%u\n", sys_div, pix_div,
                        best_pix_div);

                if (pix_div * sys_div <= best_pix_div) {
                        best_pix_div = pix_div;
                        best_div = pix_div * sys_div;
                }
        }
        if (best_pix_div == SHRT_MAX >> 1)
                return -EINVAL;

        pll_bk->sys_clk_div = best_div / best_pix_div;
        pll_bk->pix_clk_div = best_pix_div;

        pll_bk->sys_clk_freq_hz =
                pll_fr->pll_op_clk_freq_hz / pll_bk->sys_clk_div;
        pll_bk->pix_clk_freq_hz =
                pll_bk->sys_clk_freq_hz / pll_bk->pix_clk_div;

        pll->pixel_rate_pixel_array =
                pll_bk->pix_clk_freq_hz * pll->vt_lanes;

        return 0;
}

static int ccs_pll_calculate_vt_tree(struct device *dev,
                                     const struct ccs_pll_limits *lim,
                                     struct ccs_pll *pll)
{
        const struct ccs_pll_branch_limits_fr *lim_fr = &lim->vt_fr;
        struct ccs_pll_branch_fr *pll_fr = &pll->vt_fr;
        u16 min_pre_pll_clk_div = lim_fr->min_pre_pll_clk_div;
        u16 max_pre_pll_clk_div = lim_fr->max_pre_pll_clk_div;
        u32 pre_mul, pre_div;

        pre_div = gcd(pll->pixel_rate_csi,
                      pll->ext_clk_freq_hz * pll->vt_lanes);
        pre_mul = pll->pixel_rate_csi / pre_div;
        pre_div = pll->ext_clk_freq_hz * pll->vt_lanes / pre_div;

        /* Make sure PLL input frequency is within limits */
        max_pre_pll_clk_div =
                min_t(u16, max_pre_pll_clk_div,
                      DIV_ROUND_UP(pll->ext_clk_freq_hz,
                                   lim_fr->min_pll_ip_clk_freq_hz));

        min_pre_pll_clk_div = max_t(u16, min_pre_pll_clk_div,
                                    pll->ext_clk_freq_hz /
                                    lim_fr->max_pll_ip_clk_freq_hz);
        if (!(pll->flags & CCS_PLL_FLAG_EXT_IP_PLL_DIVIDER))
                min_pre_pll_clk_div = clk_div_even(min_pre_pll_clk_div);

        dev_dbg(dev, "vt min/max_pre_pll_clk_div: %u,%u\n",
                min_pre_pll_clk_div, max_pre_pll_clk_div);

        for (pll_fr->pre_pll_clk_div = min_pre_pll_clk_div;
             pll_fr->pre_pll_clk_div <= max_pre_pll_clk_div;
             pll_fr->pre_pll_clk_div +=
                     (pll->flags & CCS_PLL_FLAG_EXT_IP_PLL_DIVIDER) ? 1 :
                     2 - (pll_fr->pre_pll_clk_div & 1)) {
                u32 mul, div;
                int rval;

                div = gcd(pre_mul * pll_fr->pre_pll_clk_div, pre_div);
                mul = pre_mul * pll_fr->pre_pll_clk_div / div;
                div = pre_div / div;

                dev_dbg(dev, "vt pre-div/mul/div: %u,%u,%u\n",
                        pll_fr->pre_pll_clk_div, mul, div);

                rval = __ccs_pll_calculate_vt_tree(dev, lim, pll,
                                                   mul, div);
                if (rval)
                        continue;

                rval = check_fr_bounds(dev, lim, pll, PLL_VT);
                if (rval)
                        continue;

                rval = check_bk_bounds(dev, lim, pll, PLL_VT);
                if (rval)
                        continue;

                return 0;
        }

        dev_dbg(dev, "unable to compute VT pre_pll divisor\n");
        return -EINVAL;
}

static int
ccs_pll_calculate_vt(struct device *dev, const struct ccs_pll_limits *lim,
                     const struct ccs_pll_branch_limits_bk *op_lim_bk,
                     struct ccs_pll *pll, struct ccs_pll_branch_fr *pll_fr,
                     struct ccs_pll_branch_bk *op_pll_bk, bool cphy,
                     u32 phy_const)
{
        u16 sys_div;
        u16 best_pix_div = SHRT_MAX >> 1;
        u16 vt_op_binning_div;
        u16 min_vt_div, max_vt_div, vt_div;
        u16 min_sys_div, max_sys_div;

        if (pll->flags & CCS_PLL_FLAG_NO_OP_CLOCKS)
                goto out_calc_pixel_rate;

        /*
         * Find out whether a sensor supports derating. If it does not, VT and
         * OP domains are required to run at the same pixel rate.
         */
        if (!(pll->flags & CCS_PLL_FLAG_FIFO_DERATING)) {
                min_vt_div =
                        op_pll_bk->sys_clk_div * op_pll_bk->pix_clk_div
                        * pll->vt_lanes * phy_const / pll->op_lanes
                        / (PHY_CONST_DIV << op_pix_ddr(pll->flags));
        } else {
                /*
                 * Some sensors perform analogue binning and some do this
                 * digitally. The ones doing this digitally can be roughly be
                 * found out using this formula. The ones doing this digitally
                 * should run at higher clock rate, so smaller divisor is used
                 * on video timing side.
                 */
                if (lim->min_line_length_pck_bin > lim->min_line_length_pck
                    / pll->binning_horizontal)
                        vt_op_binning_div = pll->binning_horizontal;
                else
                        vt_op_binning_div = 1;
                dev_dbg(dev, "vt_op_binning_div: %u\n", vt_op_binning_div);

                /*
                 * Profile 2 supports vt_pix_clk_div E [4, 10]
                 *
                 * Horizontal binning can be used as a base for difference in
                 * divisors. One must make sure that horizontal blanking is
                 * enough to accommodate the CSI-2 sync codes.
                 *
                 * Take scaling factor and number of VT lanes into account as well.
                 *
                 * Find absolute limits for the factor of vt divider.
                 */
                dev_dbg(dev, "scale_m: %u\n", pll->scale_m);
                min_vt_div =
                        DIV_ROUND_UP(pll->bits_per_pixel
                                     * op_pll_bk->sys_clk_div * pll->scale_n
                                     * pll->vt_lanes * phy_const,
                                     (pll->flags &
                                      CCS_PLL_FLAG_LANE_SPEED_MODEL ?
                                      pll->csi2.lanes : 1)
                                     * vt_op_binning_div * pll->scale_m
                                     * PHY_CONST_DIV << op_pix_ddr(pll->flags));
        }

        /* Find smallest and biggest allowed vt divisor. */
        dev_dbg(dev, "min_vt_div: %u\n", min_vt_div);
        min_vt_div = max_t(u16, min_vt_div,
                           DIV_ROUND_UP(pll_fr->pll_op_clk_freq_hz,
                                        lim->vt_bk.max_pix_clk_freq_hz));
        dev_dbg(dev, "min_vt_div: max_vt_pix_clk_freq_hz: %u\n",
                min_vt_div);
        min_vt_div = max_t(u16, min_vt_div, lim->vt_bk.min_pix_clk_div
                                            * lim->vt_bk.min_sys_clk_div);
        dev_dbg(dev, "min_vt_div: min_vt_clk_div: %u\n", min_vt_div);

        max_vt_div = lim->vt_bk.max_sys_clk_div * lim->vt_bk.max_pix_clk_div;
        dev_dbg(dev, "max_vt_div: %u\n", max_vt_div);
        max_vt_div = min_t(u16, max_vt_div,
                           DIV_ROUND_UP(pll_fr->pll_op_clk_freq_hz,
                                      lim->vt_bk.min_pix_clk_freq_hz));
        dev_dbg(dev, "max_vt_div: min_vt_pix_clk_freq_hz: %u\n",
                max_vt_div);

        ccs_pll_find_vt_sys_div(dev, lim, pll, pll_fr, min_vt_div,
                                max_vt_div, &min_sys_div, &max_sys_div);

        /*
         * Find pix_div such that a legal pix_div * sys_div results
         * into a value which is not smaller than div, the desired
         * divisor.
         */
        for (vt_div = min_vt_div; vt_div <= max_vt_div; vt_div++) {
                u16 __max_sys_div = vt_div & 1 ? 1 : max_sys_div;

                for (sys_div = min_sys_div; sys_div <= __max_sys_div;
                     sys_div += 2 - (sys_div & 1)) {
                        u16 pix_div;
                        u16 rounded_div;

                        pix_div = DIV_ROUND_UP(vt_div, sys_div);

                        if (pix_div < lim->vt_bk.min_pix_clk_div
                            || pix_div > lim->vt_bk.max_pix_clk_div) {
                                dev_dbg(dev,
                                        "pix_div %u too small or too big (%u--%u)\n",
                                        pix_div,
                                        lim->vt_bk.min_pix_clk_div,
                                        lim->vt_bk.max_pix_clk_div);
                                continue;
                        }

                        rounded_div = roundup(vt_div, best_pix_div);

                        /* Check if this one is better. */
                        if (pix_div * sys_div <= rounded_div)
                                best_pix_div = pix_div;

                        /* Bail out if we've already found the best value. */
                        if (vt_div == rounded_div)
                                break;
                }
                if (best_pix_div < SHRT_MAX >> 1)
                        break;
        }
        if (best_pix_div == SHRT_MAX >> 1)
                return -EINVAL;

        pll->vt_bk.sys_clk_div = DIV_ROUND_UP(vt_div, best_pix_div);
        pll->vt_bk.pix_clk_div = best_pix_div;

        pll->vt_bk.sys_clk_freq_hz =
                pll_fr->pll_op_clk_freq_hz / pll->vt_bk.sys_clk_div;
        pll->vt_bk.pix_clk_freq_hz =
                pll->vt_bk.sys_clk_freq_hz / pll->vt_bk.pix_clk_div;

out_calc_pixel_rate:
        pll->pixel_rate_pixel_array =
                pll->vt_bk.pix_clk_freq_hz * pll->vt_lanes;

        return 0;
}

/*
 * Heuristically guess the PLL tree for a given common multiplier and
 * divisor. Begin with the operational timing and continue to video
 * timing once operational timing has been verified.
 *
 * @mul is the PLL multiplier and @div is the common divisor
 * (pre_pll_clk_div and op_sys_clk_div combined). The final PLL
 * multiplier will be a multiple of @mul.
 *
 * @return Zero on success, error code on error.
 */
static int
ccs_pll_calculate_op(struct device *dev, const struct ccs_pll_limits *lim,
                     const struct ccs_pll_branch_limits_fr *op_lim_fr,
                     const struct ccs_pll_branch_limits_bk *op_lim_bk,
                     struct ccs_pll *pll, struct ccs_pll_branch_fr *op_pll_fr,
                     struct ccs_pll_branch_bk *op_pll_bk, u32 mul,
                     u32 div, u32 op_sys_clk_freq_hz_sdr, u32 l,
                     bool cphy, u32 phy_const)
{
        /*
         * Higher multipliers (and divisors) are often required than
         * necessitated by the external clock and the output clocks.
         * There are limits for all values in the clock tree. These
         * are the minimum and maximum multiplier for mul.
         */
        u32 more_mul_min, more_mul_max;
        u32 more_mul_factor;
        u32 i;

        /*
         * Get pre_pll_clk_div so that our pll_op_clk_freq_hz won't be
         * too high.
         */
        dev_dbg(dev, "op_pre_pll_clk_div %u\n", op_pll_fr->pre_pll_clk_div);

        /* Don't go above max pll multiplier. */
        more_mul_max = op_lim_fr->max_pll_multiplier / mul;
        dev_dbg(dev, "more_mul_max: max_op_pll_multiplier check: %u\n",
                more_mul_max);
        /* Don't go above max pll op frequency. */
        more_mul_max =
                min_t(u32,
                      more_mul_max,
                      op_lim_fr->max_pll_op_clk_freq_hz
                      / (pll->ext_clk_freq_hz /
                         op_pll_fr->pre_pll_clk_div * mul));
        dev_dbg(dev, "more_mul_max: max_pll_op_clk_freq_hz check: %u\n",
                more_mul_max);
        /* Don't go above the division capability of op sys clock divider. */
        more_mul_max = min(more_mul_max,
                           op_lim_bk->max_sys_clk_div * op_pll_fr->pre_pll_clk_div
                           / div);
        dev_dbg(dev, "more_mul_max: max_op_sys_clk_div check: %u\n",
                more_mul_max);
        /* Ensure we won't go above max_pll_multiplier. */
        more_mul_max = min(more_mul_max, op_lim_fr->max_pll_multiplier / mul);
        dev_dbg(dev, "more_mul_max: min_pll_multiplier check: %u\n",
                more_mul_max);

        /* Ensure we won't go below min_pll_op_clk_freq_hz. */
        more_mul_min = DIV_ROUND_UP(op_lim_fr->min_pll_op_clk_freq_hz,
                                    pll->ext_clk_freq_hz /
                                    op_pll_fr->pre_pll_clk_div * mul);
        dev_dbg(dev, "more_mul_min: min_op_pll_op_clk_freq_hz check: %u\n",
                more_mul_min);
        /* Ensure we won't go below min_pll_multiplier. */
        more_mul_min = max(more_mul_min,
                           DIV_ROUND_UP(op_lim_fr->min_pll_multiplier, mul));
        dev_dbg(dev, "more_mul_min: min_op_pll_multiplier check: %u\n",
                more_mul_min);

        if (more_mul_min > more_mul_max) {
                dev_dbg(dev,
                        "unable to compute more_mul_min and more_mul_max\n");
                return -EINVAL;
        }

        more_mul_factor = lcm(div, op_pll_fr->pre_pll_clk_div) / div;
        dev_dbg(dev, "more_mul_factor: %u\n", more_mul_factor);
        more_mul_factor = lcm(more_mul_factor, op_lim_bk->min_sys_clk_div);
        dev_dbg(dev, "more_mul_factor: min_op_sys_clk_div: %d\n",
                more_mul_factor);
        i = roundup(more_mul_min, more_mul_factor);
        if (!is_one_or_even(i))
                i <<= 1;

        if (pll->flags & CCS_PLL_FLAG_EVEN_PLL_MULTIPLIER &&
            mul & 1 && i & 1)
                i <<= 1;

        dev_dbg(dev, "final more_mul: %u\n", i);
        if (i > more_mul_max) {
                dev_dbg(dev, "final more_mul is bad, max %u\n", more_mul_max);
                return -EINVAL;
        }

        op_pll_fr->pll_multiplier = mul * i;
        op_pll_bk->sys_clk_div = div * i / op_pll_fr->pre_pll_clk_div;
        dev_dbg(dev, "op_sys_clk_div: %u\n", op_pll_bk->sys_clk_div);

        op_pll_fr->pll_ip_clk_freq_hz = pll->ext_clk_freq_hz
                / op_pll_fr->pre_pll_clk_div;

        op_pll_fr->pll_op_clk_freq_hz = op_pll_fr->pll_ip_clk_freq_hz
                * op_pll_fr->pll_multiplier;

        if (pll->flags & CCS_PLL_FLAG_LANE_SPEED_MODEL)
                op_pll_bk->pix_clk_div =
                        (pll->bits_per_pixel
                         * pll->op_lanes * (phy_const << op_sys_ddr(pll->flags))
                         / PHY_CONST_DIV / pll->csi2.lanes / l)
                        >> op_pix_ddr(pll->flags);
        else
                op_pll_bk->pix_clk_div =
                        (pll->bits_per_pixel
                         * (phy_const << op_sys_ddr(pll->flags))
                         / PHY_CONST_DIV / l) >> op_pix_ddr(pll->flags);

        op_pll_bk->pix_clk_freq_hz =
                (op_sys_clk_freq_hz_sdr >> op_pix_ddr(pll->flags))
                / op_pll_bk->pix_clk_div;
        op_pll_bk->sys_clk_freq_hz =
                op_sys_clk_freq_hz_sdr >> op_sys_ddr(pll->flags);

        dev_dbg(dev, "op_pix_clk_div: %u\n", op_pll_bk->pix_clk_div);

        return 0;
}

int ccs_pll_calculate(struct device *dev, const struct ccs_pll_limits *lim,
                      struct ccs_pll *pll)
{
        const struct ccs_pll_branch_limits_fr *op_lim_fr;
        const struct ccs_pll_branch_limits_bk *op_lim_bk;
        struct ccs_pll_branch_fr *op_pll_fr;
        struct ccs_pll_branch_bk *op_pll_bk;
        bool cphy = pll->bus_type == CCS_PLL_BUS_TYPE_CSI2_CPHY;
        u32 phy_const = cphy ? CPHY_CONST : DPHY_CONST;
        u32 op_sys_clk_freq_hz_sdr;
        u16 min_op_pre_pll_clk_div;
        u16 max_op_pre_pll_clk_div;
        u32 mul, div;
        u32 l = (!pll->op_bits_per_lane ||
                 pll->op_bits_per_lane >= pll->bits_per_pixel) ? 1 : 2;
        u32 i;
        int rval = -EINVAL;

        print_pll_flags(dev, pll);

        if (!(pll->flags & CCS_PLL_FLAG_LANE_SPEED_MODEL)) {
                pll->op_lanes = 1;
                pll->vt_lanes = 1;
        }

        if (pll->flags & CCS_PLL_FLAG_DUAL_PLL) {
                op_lim_fr = &lim->op_fr;
                op_lim_bk = &lim->op_bk;
                op_pll_fr = &pll->op_fr;
                op_pll_bk = &pll->op_bk;
        } else if (pll->flags & CCS_PLL_FLAG_NO_OP_CLOCKS) {
                /*
                 * If there's no OP PLL at all, use the VT values
                 * instead. The OP values are ignored for the rest of
                 * the PLL calculation.
                 */
                op_lim_fr = &lim->vt_fr;
                op_lim_bk = &lim->vt_bk;
                op_pll_fr = &pll->vt_fr;
                op_pll_bk = &pll->vt_bk;
        } else {
                op_lim_fr = &lim->vt_fr;
                op_lim_bk = &lim->op_bk;
                op_pll_fr = &pll->vt_fr;
                op_pll_bk = &pll->op_bk;
        }

        if (!pll->op_lanes || !pll->vt_lanes || !pll->bits_per_pixel ||
            !pll->ext_clk_freq_hz || !pll->link_freq || !pll->scale_m ||
            !op_lim_fr->min_pll_ip_clk_freq_hz ||
            !op_lim_fr->max_pll_ip_clk_freq_hz ||
            !op_lim_fr->min_pll_op_clk_freq_hz ||
            !op_lim_fr->max_pll_op_clk_freq_hz ||
            !op_lim_bk->max_sys_clk_div || !op_lim_fr->max_pll_multiplier)
                return -EINVAL;

        /*
         * Make sure op_pix_clk_div will be integer --- unless flexible
         * op_pix_clk_div is supported
         */
        if (!(pll->flags & CCS_PLL_FLAG_FLEXIBLE_OP_PIX_CLK_DIV) &&
            (pll->bits_per_pixel * pll->op_lanes) %
            (pll->csi2.lanes * l << op_pix_ddr(pll->flags))) {
                dev_dbg(dev, "op_pix_clk_div not an integer (bpp %u, op lanes %u, lanes %u, l %u)\n",
                        pll->bits_per_pixel, pll->op_lanes, pll->csi2.lanes, l);
                return -EINVAL;
        }

        dev_dbg(dev, "vt_lanes: %u\n", pll->vt_lanes);
        dev_dbg(dev, "op_lanes: %u\n", pll->op_lanes);

        dev_dbg(dev, "binning: %ux%u\n", pll->binning_horizontal,
                pll->binning_vertical);

        switch (pll->bus_type) {
        case CCS_PLL_BUS_TYPE_CSI2_DPHY:
        case CCS_PLL_BUS_TYPE_CSI2_CPHY:
                op_sys_clk_freq_hz_sdr = pll->link_freq * 2
                        * (pll->flags & CCS_PLL_FLAG_LANE_SPEED_MODEL ?
                           1 : pll->csi2.lanes);
                break;
        default:
                return -EINVAL;
        }

        pll->pixel_rate_csi =
                div_u64((uint64_t)op_sys_clk_freq_hz_sdr
                        * (pll->flags & CCS_PLL_FLAG_LANE_SPEED_MODEL ?
                           pll->csi2.lanes : 1) * PHY_CONST_DIV,
                        phy_const * pll->bits_per_pixel * l);

        /* Figure out limits for OP pre-pll divider based on extclk */
        dev_dbg(dev, "min / max op_pre_pll_clk_div: %u / %u\n",
                op_lim_fr->min_pre_pll_clk_div, op_lim_fr->max_pre_pll_clk_div);
        max_op_pre_pll_clk_div =
                min_t(u16, op_lim_fr->max_pre_pll_clk_div,
                      DIV_ROUND_UP(pll->ext_clk_freq_hz,
                                   op_lim_fr->min_pll_ip_clk_freq_hz));
        min_op_pre_pll_clk_div =
                max_t(u16, op_lim_fr->min_pre_pll_clk_div,
                      clk_div_even_up(
                              DIV_ROUND_UP(pll->ext_clk_freq_hz,
                                           op_lim_fr->max_pll_ip_clk_freq_hz)));
        dev_dbg(dev, "pre-pll check: min / max op_pre_pll_clk_div: %u / %u\n",
                min_op_pre_pll_clk_div, max_op_pre_pll_clk_div);

        i = gcd(op_sys_clk_freq_hz_sdr,
                pll->ext_clk_freq_hz << op_pix_ddr(pll->flags));
        mul = op_sys_clk_freq_hz_sdr / i;
        div = (pll->ext_clk_freq_hz << op_pix_ddr(pll->flags)) / i;
        dev_dbg(dev, "mul %u / div %u\n", mul, div);

        min_op_pre_pll_clk_div =
                max_t(u16, min_op_pre_pll_clk_div,
                      clk_div_even_up(
                              mul /
                              one_or_more(
                                      DIV_ROUND_UP(op_lim_fr->max_pll_op_clk_freq_hz,
                                                   pll->ext_clk_freq_hz))));
        if (!(pll->flags & CCS_PLL_FLAG_EXT_IP_PLL_DIVIDER))
                min_op_pre_pll_clk_div = clk_div_even(min_op_pre_pll_clk_div);
        dev_dbg(dev, "pll_op check: min / max op_pre_pll_clk_div: %u / %u\n",
                min_op_pre_pll_clk_div, max_op_pre_pll_clk_div);

        for (op_pll_fr->pre_pll_clk_div = min_op_pre_pll_clk_div;
             op_pll_fr->pre_pll_clk_div <= max_op_pre_pll_clk_div;
             op_pll_fr->pre_pll_clk_div +=
                     (pll->flags & CCS_PLL_FLAG_EXT_IP_PLL_DIVIDER) ? 1 :
                     2 - (op_pll_fr->pre_pll_clk_div & 1)) {
                rval = ccs_pll_calculate_op(dev, lim, op_lim_fr, op_lim_bk, pll,
                                            op_pll_fr, op_pll_bk, mul, div,
                                            op_sys_clk_freq_hz_sdr, l, cphy,
                                            phy_const);
                if (rval)
                        continue;

                rval = check_fr_bounds(dev, lim, pll,
                                       pll->flags & CCS_PLL_FLAG_DUAL_PLL ?
                                       PLL_OP : PLL_VT);
                if (rval)
                        continue;

                rval = check_bk_bounds(dev, lim, pll, PLL_OP);
                if (rval)
                        continue;

                if (pll->flags & CCS_PLL_FLAG_DUAL_PLL)
                        break;

                rval = ccs_pll_calculate_vt(dev, lim, op_lim_bk, pll, op_pll_fr,
                                            op_pll_bk, cphy, phy_const);
                if (rval)
                        continue;

                rval = check_bk_bounds(dev, lim, pll, PLL_VT);
                if (rval)
                        continue;
                rval = check_ext_bounds(dev, pll);
                if (rval)
                        continue;

                break;
        }

        if (rval) {
                dev_dbg(dev, "unable to compute OP pre_pll divisor\n");
                return rval;
        }

        if (pll->flags & CCS_PLL_FLAG_DUAL_PLL) {
                rval = ccs_pll_calculate_vt_tree(dev, lim, pll);

                if (rval)
                        return rval;
        }

        print_pll(dev, pll);

        return 0;
}
EXPORT_SYMBOL_GPL(ccs_pll_calculate);

MODULE_AUTHOR("Sakari Ailus <sakari.ailus@linux.intel.com>");
MODULE_DESCRIPTION("Generic MIPI CCS/SMIA/SMIA++ PLL calculator");
MODULE_LICENSE("GPL");