/*
 * Copyright 2013 Broadcom Corporation.
 *
 * SPDX-License-Identifier:      GPL-2.0+
 */

/*
 *
 * bcm281xx architecture clock framework
 *
 */

#include <common.h>
#include <asm/io.h>
#include <linux/errno.h>
#include <bitfield.h>
#include <asm/arch/sysmap.h>
#include <asm/kona-common/clk.h>
#include "clk-core.h"

#define CLK_WR_ACCESS_PASSWORD  0x00a5a501
#define WR_ACCESS_OFFSET        0       /* common to all clock blocks */
#define POLICY_CTL_GO           1       /* Load and refresh policy masks */
#define POLICY_CTL_GO_ATL       4       /* Active Load */

/* Helper function */
int clk_get_and_enable(char *clkstr)
{
        int ret = 0;
        struct clk *c;

        debug("%s: %s\n", __func__, clkstr);

        c = clk_get(clkstr);
        if (c) {
                ret = clk_enable(c);
                if (ret)
                        return ret;
        } else {
                printf("%s: Couldn't find %s\n", __func__, clkstr);
                return -EINVAL;
        }
        return ret;
}

/*
 * Poll a register in a CCU's address space, returning when the
 * specified bit in that register's value is set (or clear).  Delay
 * a microsecond after each read of the register.  Returns true if
 * successful, or false if we gave up trying.
 *
 * Caller must ensure the CCU lock is held.
 */
#define CLK_GATE_DELAY_USEC 2000
static inline int wait_bit(void *base, u32 offset, u32 bit, bool want)
{
        unsigned int tries;
        u32 bit_mask = 1 << bit;

        for (tries = 0; tries < CLK_GATE_DELAY_USEC; tries++) {
                u32 val;
                bool bit_val;

                val = readl(base + offset);
                bit_val = (val & bit_mask) ? 1 : 0;
                if (bit_val == want)
                        return 0;       /* success */
                udelay(1);
        }

        debug("%s: timeout on addr 0x%p, waiting for bit %d to go to %d\n",
              __func__, base + offset, bit, want);

        return -ETIMEDOUT;
}

/* Enable a peripheral clock */
static int peri_clk_enable(struct clk *c, int enable)
{
        int ret = 0;
        u32 reg;
        struct peri_clock *peri_clk = to_peri_clk(c);
        struct peri_clk_data *cd = peri_clk->data;
        struct bcm_clk_gate *gate = &cd->gate;
        void *base = (void *)c->ccu_clk_mgr_base;


        debug("%s: %s\n", __func__, c->name);

        clk_get_rate(c);        /* Make sure rate and sel are filled in */

        /* enable access */
        writel(CLK_WR_ACCESS_PASSWORD, base + WR_ACCESS_OFFSET);

        if (enable) {
                debug("%s %s set rate %lu div %lu sel %d parent %lu\n",
                      __func__, c->name, c->rate, c->div, c->sel,
                      c->parent->rate);

                /*
                 * clkgate - only software controllable gates are
                 * supported by u-boot which includes all clocks
                 * that matter. This avoids bringing in a lot of extra
                 * complexity as done in the kernel framework.
                 */
                if (gate_exists(gate)) {
                        reg = readl(base + cd->gate.offset);
                        reg |= (1 << cd->gate.en_bit);
                        writel(reg, base + cd->gate.offset);
                }

                /* div and pll select */
                if (divider_exists(&cd->div)) {
                        reg = readl(base + cd->div.offset);
                        bitfield_replace(reg, cd->div.shift, cd->div.width,
                                         c->div - 1);
                        writel(reg, base + cd->div.offset);
                }

                /* frequency selector */
                if (selector_exists(&cd->sel)) {
                        reg = readl(base + cd->sel.offset);
                        bitfield_replace(reg, cd->sel.shift, cd->sel.width,
                                         c->sel);
                        writel(reg, base + cd->sel.offset);
                }

                /* trigger */
                if (trigger_exists(&cd->trig)) {
                        writel((1 << cd->trig.bit), base + cd->trig.offset);

                        /* wait for trigger status bit to go to 0 */
                        ret = wait_bit(base, cd->trig.offset, cd->trig.bit, 0);
                        if (ret)
                                return ret;
                }

                /* wait for running (status_bit = 1) */
                ret = wait_bit(base, cd->gate.offset, cd->gate.status_bit, 1);
                if (ret)
                        return ret;
        } else {
                debug("%s disable clock %s\n", __func__, c->name);

                /* clkgate */
                reg = readl(base + cd->gate.offset);
                reg &= ~(1 << cd->gate.en_bit);
                writel(reg, base + cd->gate.offset);

                /* wait for stop (status_bit = 0) */
                ret = wait_bit(base, cd->gate.offset, cd->gate.status_bit, 0);
        }

        /* disable access */
        writel(0, base + WR_ACCESS_OFFSET);

        return ret;
}

/* Set the rate of a peripheral clock */
static int peri_clk_set_rate(struct clk *c, unsigned long rate)
{
        int ret = 0;
        int i;
        unsigned long diff;
        unsigned long new_rate = 0, div = 1;
        struct peri_clock *peri_clk = to_peri_clk(c);
        struct peri_clk_data *cd = peri_clk->data;
        const char **clock;

        debug("%s: %s\n", __func__, c->name);
        diff = rate;

        i = 0;
        for (clock = cd->clocks; *clock; clock++, i++) {
                struct refclk *ref = refclk_str_to_clk(*clock);
                if (!ref) {
                        printf("%s: Lookup of %s failed\n", __func__, *clock);
                        return -EINVAL;
                }

                /* round to the new rate */
                div = ref->clk.rate / rate;
                if (div == 0)
                        div = 1;

                new_rate = ref->clk.rate / div;

                /* get the min diff */
                if (abs(new_rate - rate) < diff) {
                        diff = abs(new_rate - rate);
                        c->sel = i;
                        c->parent = &ref->clk;
                        c->rate = new_rate;
                        c->div = div;
                }
        }

        debug("%s %s set rate %lu div %lu sel %d parent %lu\n", __func__,
              c->name, c->rate, c->div, c->sel, c->parent->rate);
        return ret;
}

/* Get the rate of a peripheral clock */
static unsigned long peri_clk_get_rate(struct clk *c)
{
        struct peri_clock *peri_clk = to_peri_clk(c);
        struct peri_clk_data *cd = peri_clk->data;
        void *base = (void *)c->ccu_clk_mgr_base;
        int div = 1;
        const char **clock;
        struct refclk *ref;
        u32 reg;

        debug("%s: %s\n", __func__, c->name);
        if (selector_exists(&cd->sel)) {
                reg = readl(base + cd->sel.offset);
                c->sel = bitfield_extract(reg, cd->sel.shift, cd->sel.width);
        } else {
                /*
                 * For peri clocks that don't have a selector, the single
                 * reference clock will always exist at index 0.
                 */
                c->sel = 0;
        }

        if (divider_exists(&cd->div)) {
                reg = readl(base + cd->div.offset);
                div = bitfield_extract(reg, cd->div.shift, cd->div.width);
                div += 1;
        }

        clock = cd->clocks;
        ref = refclk_str_to_clk(clock[c->sel]);
        if (!ref) {
                printf("%s: Can't lookup %s\n", __func__, clock[c->sel]);
                return 0;
        }

        c->parent = &ref->clk;
        c->div = div;
        c->rate = c->parent->rate / c->div;
        debug("%s parent rate %lu div %d sel %d rate %lu\n", __func__,
              c->parent->rate, div, c->sel, c->rate);

        return c->rate;
}

/* Peripheral clock operations */
struct clk_ops peri_clk_ops = {
        .enable = peri_clk_enable,
        .set_rate = peri_clk_set_rate,
        .get_rate = peri_clk_get_rate,
};

/* Enable a CCU clock */
static int ccu_clk_enable(struct clk *c, int enable)
{
        struct ccu_clock *ccu_clk = to_ccu_clk(c);
        void *base = (void *)c->ccu_clk_mgr_base;
        int ret = 0;
        u32 reg;

        debug("%s: %s\n", __func__, c->name);
        if (!enable)
                return -EINVAL; /* CCU clock cannot shutdown */

        /* enable access */
        writel(CLK_WR_ACCESS_PASSWORD, base + WR_ACCESS_OFFSET);

        /* config enable for policy engine */
        writel(1, base + ccu_clk->lvm_en_offset);

        /* wait for bit to go to 0 */
        ret = wait_bit(base, ccu_clk->lvm_en_offset, 0, 0);
        if (ret)
                return ret;

        /* freq ID */
        if (!ccu_clk->freq_bit_shift)
                ccu_clk->freq_bit_shift = 8;

        /* Set frequency id for each of the 4 policies */
        reg = ccu_clk->freq_id |
            (ccu_clk->freq_id << (ccu_clk->freq_bit_shift)) |
            (ccu_clk->freq_id << (ccu_clk->freq_bit_shift * 2)) |
            (ccu_clk->freq_id << (ccu_clk->freq_bit_shift * 3));
        writel(reg, base + ccu_clk->policy_freq_offset);

        /* enable all clock mask */
        writel(0x7fffffff, base + ccu_clk->policy0_mask_offset);
        writel(0x7fffffff, base + ccu_clk->policy1_mask_offset);
        writel(0x7fffffff, base + ccu_clk->policy2_mask_offset);
        writel(0x7fffffff, base + ccu_clk->policy3_mask_offset);

        if (ccu_clk->num_policy_masks == 2) {
                writel(0x7fffffff, base + ccu_clk->policy0_mask2_offset);
                writel(0x7fffffff, base + ccu_clk->policy1_mask2_offset);
                writel(0x7fffffff, base + ccu_clk->policy2_mask2_offset);
                writel(0x7fffffff, base + ccu_clk->policy3_mask2_offset);
        }

        /* start policy engine */
        reg = readl(base + ccu_clk->policy_ctl_offset);
        reg |= (POLICY_CTL_GO + POLICY_CTL_GO_ATL);
        writel(reg, base + ccu_clk->policy_ctl_offset);

        /* wait till started */
        ret = wait_bit(base, ccu_clk->policy_ctl_offset, 0, 0);
        if (ret)
                return ret;

        /* disable access */
        writel(0, base + WR_ACCESS_OFFSET);

        return ret;
}

/* Get the CCU clock rate */
static unsigned long ccu_clk_get_rate(struct clk *c)
{
        struct ccu_clock *ccu_clk = to_ccu_clk(c);
        debug("%s: %s\n", __func__, c->name);
        c->rate = ccu_clk->freq_tbl[ccu_clk->freq_id];
        return c->rate;
}

/* CCU clock operations */
struct clk_ops ccu_clk_ops = {
        .enable = ccu_clk_enable,
        .get_rate = ccu_clk_get_rate,
};

/* Enable a bus clock */
static int bus_clk_enable(struct clk *c, int enable)
{
        struct bus_clock *bus_clk = to_bus_clk(c);
        struct bus_clk_data *cd = bus_clk->data;
        void *base = (void *)c->ccu_clk_mgr_base;
        int ret = 0;
        u32 reg;

        debug("%s: %s\n", __func__, c->name);
        /* enable access */
        writel(CLK_WR_ACCESS_PASSWORD, base + WR_ACCESS_OFFSET);

        /* enable gating */
        reg = readl(base + cd->gate.offset);
        if (!!(reg & (1 << cd->gate.status_bit)) == !!enable)
                debug("%s already %s\n", c->name,
                      enable ? "enabled" : "disabled");
        else {
                int want = (enable) ? 1 : 0;
                reg |= (1 << cd->gate.hw_sw_sel_bit);

                if (enable)
                        reg |= (1 << cd->gate.en_bit);
                else
                        reg &= ~(1 << cd->gate.en_bit);

                writel(reg, base + cd->gate.offset);
                ret = wait_bit(base, cd->gate.offset, cd->gate.status_bit,
                               want);
                if (ret)
                        return ret;
        }

        /* disable access */
        writel(0, base + WR_ACCESS_OFFSET);

        return ret;
}

/* Get the rate of a bus clock */
static unsigned long bus_clk_get_rate(struct clk *c)
{
        struct bus_clock *bus_clk = to_bus_clk(c);
        struct ccu_clock *ccu_clk;

        debug("%s: %s\n", __func__, c->name);
        ccu_clk = to_ccu_clk(c->parent);

        c->rate = bus_clk->freq_tbl[ccu_clk->freq_id];
        c->div = ccu_clk->freq_tbl[ccu_clk->freq_id] / c->rate;
        return c->rate;
}

/* Bus clock operations */
struct clk_ops bus_clk_ops = {
        .enable = bus_clk_enable,
        .get_rate = bus_clk_get_rate,
};

/* Enable a reference clock */
static int ref_clk_enable(struct clk *c, int enable)
{
        debug("%s: %s\n", __func__, c->name);
        return 0;
}

/* Reference clock operations */
struct clk_ops ref_clk_ops = {
        .enable = ref_clk_enable,
};

/*
 * clk.h implementation follows
 */

/* Initialize the clock framework */
int clk_init(void)
{
        debug("%s:\n", __func__);
        return 0;
}

/* Get a clock handle, give a name string */
struct clk *clk_get(const char *con_id)
{
        int i;
        struct clk_lookup *clk_tblp;

        debug("%s: %s\n", __func__, con_id);

        clk_tblp = arch_clk_tbl;
        for (i = 0; i < arch_clk_tbl_array_size; i++, clk_tblp++) {
                if (clk_tblp->con_id) {
                        if (!con_id || strcmp(clk_tblp->con_id, con_id))
                                continue;
                        return clk_tblp->clk;
                }
        }
        return NULL;
}

/* Enable a clock */
int clk_enable(struct clk *c)
{
        int ret = 0;

        debug("%s: %s\n", __func__, c->name);
        if (!c->ops || !c->ops->enable)
                return -1;

        /* enable parent clock first */
        if (c->parent)
                ret = clk_enable(c->parent);

        if (ret)
                return ret;

        if (!c->use_cnt) {
                c->use_cnt++;
                ret = c->ops->enable(c, 1);
        }

        return ret;
}

/* Disable a clock */
void clk_disable(struct clk *c)
{
        debug("%s: %s\n", __func__, c->name);
        if (!c->ops || !c->ops->enable)
                return;

        if (c->use_cnt) {
                c->use_cnt--;
                c->ops->enable(c, 0);
        }

        /* disable parent */
        if (c->parent)
                clk_disable(c->parent);
}

/* Get the clock rate */
unsigned long clk_get_rate(struct clk *c)
{
        unsigned long rate;

        if (!c || !c->ops || !c->ops->get_rate)
                return 0;
        debug("%s: %s\n", __func__, c->name);

        rate = c->ops->get_rate(c);
        debug("%s: rate = %ld\n", __func__, rate);
        return rate;
}

/* Set the clock rate */
int clk_set_rate(struct clk *c, unsigned long rate)
{
        int ret;

        if (!c || !c->ops || !c->ops->set_rate)
                return -EINVAL;
        debug("%s: %s rate=%ld\n", __func__, c->name, rate);

        if (c->use_cnt)
                return -EINVAL;

        ret = c->ops->set_rate(c, rate);

        return ret;
}

/* Not required for this arch */
/*
long clk_round_rate(struct clk *clk, unsigned long rate);
int clk_set_parent(struct clk *clk, struct clk *parent);
struct clk *clk_get_parent(struct clk *clk);
*/