serial: pxa: fine-tune clk useage

[linux/fpc-iii.git] / arch / arm / mach-omap2 / dpll3xxx.c

/*
 * OMAP3/4 - specific DPLL control functions
 *
 * Copyright (C) 2009-2010 Texas Instruments, Inc.
 * Copyright (C) 2009-2010 Nokia Corporation
 *
 * Written by Paul Walmsley
 * Testing and integration fixes by Jouni Högander
 *
 * 36xx support added by Vishwanath BS, Richard Woodruff, and Nishanth
 * Menon
 *
 * Parts of this code are based on code written by
 * Richard Woodruff, Tony Lindgren, Tuukka Tikkanen, Karthik Dasu
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/bitops.h>
#include <linux/clkdev.h>

#include "soc.h"
#include "clockdomain.h"
#include "clock.h"
#include "cm2xxx_3xxx.h"
#include "cm-regbits-34xx.h"

/* CM_AUTOIDLE_PLL*.AUTO_* bit values */
#define DPLL_AUTOIDLE_DISABLE                   0x0
#define DPLL_AUTOIDLE_LOW_POWER_STOP            0x1

#define MAX_DPLL_WAIT_TRIES             1000000

/* Private functions */

/* _omap3_dpll_write_clken - write clken_bits arg to a DPLL's enable bits */
static void _omap3_dpll_write_clken(struct clk_hw_omap *clk, u8 clken_bits)
{
        const struct dpll_data *dd;
        u32 v;

        dd = clk->dpll_data;

        v = __raw_readl(dd->control_reg);
        v &= ~dd->enable_mask;
        v |= clken_bits << __ffs(dd->enable_mask);
        __raw_writel(v, dd->control_reg);
}

/* _omap3_wait_dpll_status: wait for a DPLL to enter a specific state */
static int _omap3_wait_dpll_status(struct clk_hw_omap *clk, u8 state)
{
        const struct dpll_data *dd;
        int i = 0;
        int ret = -EINVAL;
        const char *clk_name;

        dd = clk->dpll_data;
        clk_name = __clk_get_name(clk->hw.clk);

        state <<= __ffs(dd->idlest_mask);

        while (((__raw_readl(dd->idlest_reg) & dd->idlest_mask) != state) &&
               i < MAX_DPLL_WAIT_TRIES) {
                i++;
                udelay(1);
        }

        if (i == MAX_DPLL_WAIT_TRIES) {
                printk(KERN_ERR "clock: %s failed transition to '%s'\n",
                       clk_name, (state) ? "locked" : "bypassed");
        } else {
                pr_debug("clock: %s transition to '%s' in %d loops\n",
                         clk_name, (state) ? "locked" : "bypassed", i);

                ret = 0;
        }

        return ret;
}

/* From 3430 TRM ES2 4.7.6.2 */
static u16 _omap3_dpll_compute_freqsel(struct clk_hw_omap *clk, u8 n)
{
        unsigned long fint;
        u16 f = 0;

        fint = __clk_get_rate(clk->dpll_data->clk_ref) / n;

        pr_debug("clock: fint is %lu\n", fint);

        if (fint >= 750000 && fint <= 1000000)
                f = 0x3;
        else if (fint > 1000000 && fint <= 1250000)
                f = 0x4;
        else if (fint > 1250000 && fint <= 1500000)
                f = 0x5;
        else if (fint > 1500000 && fint <= 1750000)
                f = 0x6;
        else if (fint > 1750000 && fint <= 2100000)
                f = 0x7;
        else if (fint > 7500000 && fint <= 10000000)
                f = 0xB;
        else if (fint > 10000000 && fint <= 12500000)
                f = 0xC;
        else if (fint > 12500000 && fint <= 15000000)
                f = 0xD;
        else if (fint > 15000000 && fint <= 17500000)
                f = 0xE;
        else if (fint > 17500000 && fint <= 21000000)
                f = 0xF;
        else
                pr_debug("clock: unknown freqsel setting for %d\n", n);

        return f;
}

/*
 * _omap3_noncore_dpll_lock - instruct a DPLL to lock and wait for readiness
 * @clk: pointer to a DPLL struct clk
 *
 * Instructs a non-CORE DPLL to lock.  Waits for the DPLL to report
 * readiness before returning.  Will save and restore the DPLL's
 * autoidle state across the enable, per the CDP code.  If the DPLL
 * locked successfully, return 0; if the DPLL did not lock in the time
 * allotted, or DPLL3 was passed in, return -EINVAL.
 */
static int _omap3_noncore_dpll_lock(struct clk_hw_omap *clk)
{
        const struct dpll_data *dd;
        u8 ai;
        u8 state = 1;
        int r = 0;

        pr_debug("clock: locking DPLL %s\n", __clk_get_name(clk->hw.clk));

        dd = clk->dpll_data;
        state <<= __ffs(dd->idlest_mask);

        /* Check if already locked */
        if ((__raw_readl(dd->idlest_reg) & dd->idlest_mask) == state)
                goto done;

        ai = omap3_dpll_autoidle_read(clk);

        if (ai)
                omap3_dpll_deny_idle(clk);

        _omap3_dpll_write_clken(clk, DPLL_LOCKED);

        r = _omap3_wait_dpll_status(clk, 1);

        if (ai)
                omap3_dpll_allow_idle(clk);

done:
        return r;
}

/*
 * _omap3_noncore_dpll_bypass - instruct a DPLL to bypass and wait for readiness
 * @clk: pointer to a DPLL struct clk
 *
 * Instructs a non-CORE DPLL to enter low-power bypass mode.  In
 * bypass mode, the DPLL's rate is set equal to its parent clock's
 * rate.  Waits for the DPLL to report readiness before returning.
 * Will save and restore the DPLL's autoidle state across the enable,
 * per the CDP code.  If the DPLL entered bypass mode successfully,
 * return 0; if the DPLL did not enter bypass in the time allotted, or
 * DPLL3 was passed in, or the DPLL does not support low-power bypass,
 * return -EINVAL.
 */
static int _omap3_noncore_dpll_bypass(struct clk_hw_omap *clk)
{
        int r;
        u8 ai;

        if (!(clk->dpll_data->modes & (1 << DPLL_LOW_POWER_BYPASS)))
                return -EINVAL;

        pr_debug("clock: configuring DPLL %s for low-power bypass\n",
                 __clk_get_name(clk->hw.clk));

        ai = omap3_dpll_autoidle_read(clk);

        _omap3_dpll_write_clken(clk, DPLL_LOW_POWER_BYPASS);

        r = _omap3_wait_dpll_status(clk, 0);

        if (ai)
                omap3_dpll_allow_idle(clk);

        return r;
}

/*
 * _omap3_noncore_dpll_stop - instruct a DPLL to stop
 * @clk: pointer to a DPLL struct clk
 *
 * Instructs a non-CORE DPLL to enter low-power stop. Will save and
 * restore the DPLL's autoidle state across the stop, per the CDP
 * code.  If DPLL3 was passed in, or the DPLL does not support
 * low-power stop, return -EINVAL; otherwise, return 0.
 */
static int _omap3_noncore_dpll_stop(struct clk_hw_omap *clk)
{
        u8 ai;

        if (!(clk->dpll_data->modes & (1 << DPLL_LOW_POWER_STOP)))
                return -EINVAL;

        pr_debug("clock: stopping DPLL %s\n", __clk_get_name(clk->hw.clk));

        ai = omap3_dpll_autoidle_read(clk);

        _omap3_dpll_write_clken(clk, DPLL_LOW_POWER_STOP);

        if (ai)
                omap3_dpll_allow_idle(clk);

        return 0;
}

/**
 * _lookup_dco - Lookup DCO used by j-type DPLL
 * @clk: pointer to a DPLL struct clk
 * @dco: digital control oscillator selector
 * @m: DPLL multiplier to set
 * @n: DPLL divider to set
 *
 * See 36xx TRM section 3.5.3.3.3.2 "Type B DPLL (Low-Jitter)"
 *
 * XXX This code is not needed for 3430/AM35xx; can it be optimized
 * out in non-multi-OMAP builds for those chips?
 */
static void _lookup_dco(struct clk_hw_omap *clk, u8 *dco, u16 m, u8 n)
{
        unsigned long fint, clkinp; /* watch out for overflow */

        clkinp = __clk_get_rate(__clk_get_parent(clk->hw.clk));
        fint = (clkinp / n) * m;

        if (fint < 1000000000)
                *dco = 2;
        else
                *dco = 4;
}

/**
 * _lookup_sddiv - Calculate sigma delta divider for j-type DPLL
 * @clk: pointer to a DPLL struct clk
 * @sd_div: target sigma-delta divider
 * @m: DPLL multiplier to set
 * @n: DPLL divider to set
 *
 * See 36xx TRM section 3.5.3.3.3.2 "Type B DPLL (Low-Jitter)"
 *
 * XXX This code is not needed for 3430/AM35xx; can it be optimized
 * out in non-multi-OMAP builds for those chips?
 */
static void _lookup_sddiv(struct clk_hw_omap *clk, u8 *sd_div, u16 m, u8 n)
{
        unsigned long clkinp, sd; /* watch out for overflow */
        int mod1, mod2;

        clkinp = __clk_get_rate(__clk_get_parent(clk->hw.clk));

        /*
         * target sigma-delta to near 250MHz
         * sd = ceil[(m/(n+1)) * (clkinp_MHz / 250)]
         */
        clkinp /= 100000; /* shift from MHz to 10*Hz for 38.4 and 19.2 */
        mod1 = (clkinp * m) % (250 * n);
        sd = (clkinp * m) / (250 * n);
        mod2 = sd % 10;
        sd /= 10;

        if (mod1 || mod2)
                sd++;
        *sd_div = sd;
}

/*
 * _omap3_noncore_dpll_program - set non-core DPLL M,N values directly
 * @clk:        struct clk * of DPLL to set
 * @freqsel:    FREQSEL value to set
 *
 * Program the DPLL with the last M, N values calculated, and wait for
 * the DPLL to lock. Returns -EINVAL upon error, or 0 upon success.
 */
static int omap3_noncore_dpll_program(struct clk_hw_omap *clk, u16 freqsel)
{
        struct dpll_data *dd = clk->dpll_data;
        u8 dco, sd_div;
        u32 v;

        /* 3430 ES2 TRM: 4.7.6.9 DPLL Programming Sequence */
        _omap3_noncore_dpll_bypass(clk);

        /*
         * Set jitter correction. No jitter correction for OMAP4 and 3630
         * since freqsel field is no longer present
         */
        if (!soc_is_am33xx() && !cpu_is_omap44xx() && !cpu_is_omap3630()) {
                v = __raw_readl(dd->control_reg);
                v &= ~dd->freqsel_mask;
                v |= freqsel << __ffs(dd->freqsel_mask);
                __raw_writel(v, dd->control_reg);
        }

        /* Set DPLL multiplier, divider */
        v = __raw_readl(dd->mult_div1_reg);
        v &= ~(dd->mult_mask | dd->div1_mask);
        v |= dd->last_rounded_m << __ffs(dd->mult_mask);
        v |= (dd->last_rounded_n - 1) << __ffs(dd->div1_mask);

        /* Configure dco and sd_div for dplls that have these fields */
        if (dd->dco_mask) {
                _lookup_dco(clk, &dco, dd->last_rounded_m, dd->last_rounded_n);
                v &= ~(dd->dco_mask);
                v |= dco << __ffs(dd->dco_mask);
        }
        if (dd->sddiv_mask) {
                _lookup_sddiv(clk, &sd_div, dd->last_rounded_m,
                              dd->last_rounded_n);
                v &= ~(dd->sddiv_mask);
                v |= sd_div << __ffs(dd->sddiv_mask);
        }

        __raw_writel(v, dd->mult_div1_reg);

        /* Set 4X multiplier and low-power mode */
        if (dd->m4xen_mask || dd->lpmode_mask) {
                v = __raw_readl(dd->control_reg);

                if (dd->m4xen_mask) {
                        if (dd->last_rounded_m4xen)
                                v |= dd->m4xen_mask;
                        else
                                v &= ~dd->m4xen_mask;
                }

                if (dd->lpmode_mask) {
                        if (dd->last_rounded_lpmode)
                                v |= dd->lpmode_mask;
                        else
                                v &= ~dd->lpmode_mask;
                }

                __raw_writel(v, dd->control_reg);
        }

        /* We let the clock framework set the other output dividers later */

        /* REVISIT: Set ramp-up delay? */

        _omap3_noncore_dpll_lock(clk);

        return 0;
}

/* Public functions */

/**
 * omap3_dpll_recalc - recalculate DPLL rate
 * @clk: DPLL struct clk
 *
 * Recalculate and propagate the DPLL rate.
 */
unsigned long omap3_dpll_recalc(struct clk_hw *hw, unsigned long parent_rate)
{
        struct clk_hw_omap *clk = to_clk_hw_omap(hw);

        return omap2_get_dpll_rate(clk);
}

/* Non-CORE DPLL (e.g., DPLLs that do not control SDRC) clock functions */

/**
 * omap3_noncore_dpll_enable - instruct a DPLL to enter bypass or lock mode
 * @clk: pointer to a DPLL struct clk
 *
 * Instructs a non-CORE DPLL to enable, e.g., to enter bypass or lock.
 * The choice of modes depends on the DPLL's programmed rate: if it is
 * the same as the DPLL's parent clock, it will enter bypass;
 * otherwise, it will enter lock.  This code will wait for the DPLL to
 * indicate readiness before returning, unless the DPLL takes too long
 * to enter the target state.  Intended to be used as the struct clk's
 * enable function.  If DPLL3 was passed in, or the DPLL does not
 * support low-power stop, or if the DPLL took too long to enter
 * bypass or lock, return -EINVAL; otherwise, return 0.
 */
int omap3_noncore_dpll_enable(struct clk_hw *hw)
{
        struct clk_hw_omap *clk = to_clk_hw_omap(hw);
        int r;
        struct dpll_data *dd;
        struct clk *parent;

        dd = clk->dpll_data;
        if (!dd)
                return -EINVAL;

        if (clk->clkdm) {
                r = clkdm_clk_enable(clk->clkdm, hw->clk);
                if (r) {
                        WARN(1,
                             "%s: could not enable %s's clockdomain %s: %d\n",
                             __func__, __clk_get_name(hw->clk),
                             clk->clkdm->name, r);
                        return r;
                }
        }

        parent = __clk_get_parent(hw->clk);

        if (__clk_get_rate(hw->clk) == __clk_get_rate(dd->clk_bypass)) {
                WARN_ON(parent != dd->clk_bypass);
                r = _omap3_noncore_dpll_bypass(clk);
        } else {
                WARN_ON(parent != dd->clk_ref);
                r = _omap3_noncore_dpll_lock(clk);
        }

        return r;
}

/**
 * omap3_noncore_dpll_disable - instruct a DPLL to enter low-power stop
 * @clk: pointer to a DPLL struct clk
 *
 * Instructs a non-CORE DPLL to enter low-power stop.  This function is
 * intended for use in struct clkops.  No return value.
 */
void omap3_noncore_dpll_disable(struct clk_hw *hw)
{
        struct clk_hw_omap *clk = to_clk_hw_omap(hw);

        _omap3_noncore_dpll_stop(clk);
        if (clk->clkdm)
                clkdm_clk_disable(clk->clkdm, hw->clk);
}


/* Non-CORE DPLL rate set code */

/**
 * omap3_noncore_dpll_set_rate - set non-core DPLL rate
 * @clk: struct clk * of DPLL to set
 * @rate: rounded target rate
 *
 * Set the DPLL CLKOUT to the target rate.  If the DPLL can enter
 * low-power bypass, and the target rate is the bypass source clock
 * rate, then configure the DPLL for bypass.  Otherwise, round the
 * target rate if it hasn't been done already, then program and lock
 * the DPLL.  Returns -EINVAL upon error, or 0 upon success.
 */
int omap3_noncore_dpll_set_rate(struct clk_hw *hw, unsigned long rate,
                                        unsigned long parent_rate)
{
        struct clk_hw_omap *clk = to_clk_hw_omap(hw);
        struct clk *new_parent = NULL;
        u16 freqsel = 0;
        struct dpll_data *dd;
        int ret;

        if (!hw || !rate)
                return -EINVAL;

        dd = clk->dpll_data;
        if (!dd)
                return -EINVAL;

        __clk_prepare(dd->clk_bypass);
        clk_enable(dd->clk_bypass);
        __clk_prepare(dd->clk_ref);
        clk_enable(dd->clk_ref);

        if (__clk_get_rate(dd->clk_bypass) == rate &&
            (dd->modes & (1 << DPLL_LOW_POWER_BYPASS))) {
                pr_debug("%s: %s: set rate: entering bypass.\n",
                         __func__, __clk_get_name(hw->clk));

                ret = _omap3_noncore_dpll_bypass(clk);
                if (!ret)
                        new_parent = dd->clk_bypass;
        } else {
                if (dd->last_rounded_rate != rate)
                        rate = __clk_round_rate(hw->clk, rate);

                if (dd->last_rounded_rate == 0)
                        return -EINVAL;

                /* No freqsel on OMAP4 and OMAP3630 */
                if (!cpu_is_omap44xx() && !cpu_is_omap3630()) {
                        freqsel = _omap3_dpll_compute_freqsel(clk,
                                                dd->last_rounded_n);
                        WARN_ON(!freqsel);
                }

                pr_debug("%s: %s: set rate: locking rate to %lu.\n",
                         __func__, __clk_get_name(hw->clk), rate);

                ret = omap3_noncore_dpll_program(clk, freqsel);
                if (!ret)
                        new_parent = dd->clk_ref;
        }
        /*
        * FIXME - this is all wrong.  common code handles reparenting and
        * migrating prepare/enable counts.  dplls should be a multiplexer
        * clock and this should be a set_parent operation so that all of that
        * stuff is inherited for free
        */

        if (!ret)
                __clk_reparent(hw->clk, new_parent);

        clk_disable(dd->clk_ref);
        __clk_unprepare(dd->clk_ref);
        clk_disable(dd->clk_bypass);
        __clk_unprepare(dd->clk_bypass);

        return 0;
}

/* DPLL autoidle read/set code */

/**
 * omap3_dpll_autoidle_read - read a DPLL's autoidle bits
 * @clk: struct clk * of the DPLL to read
 *
 * Return the DPLL's autoidle bits, shifted down to bit 0.  Returns
 * -EINVAL if passed a null pointer or if the struct clk does not
 * appear to refer to a DPLL.
 */
u32 omap3_dpll_autoidle_read(struct clk_hw_omap *clk)
{
        const struct dpll_data *dd;
        u32 v;

        if (!clk || !clk->dpll_data)
                return -EINVAL;

        dd = clk->dpll_data;

        if (!dd->autoidle_reg)
                return -EINVAL;

        v = __raw_readl(dd->autoidle_reg);
        v &= dd->autoidle_mask;
        v >>= __ffs(dd->autoidle_mask);

        return v;
}

/**
 * omap3_dpll_allow_idle - enable DPLL autoidle bits
 * @clk: struct clk * of the DPLL to operate on
 *
 * Enable DPLL automatic idle control.  This automatic idle mode
 * switching takes effect only when the DPLL is locked, at least on
 * OMAP3430.  The DPLL will enter low-power stop when its downstream
 * clocks are gated.  No return value.
 */
void omap3_dpll_allow_idle(struct clk_hw_omap *clk)
{
        const struct dpll_data *dd;
        u32 v;

        if (!clk || !clk->dpll_data)
                return;

        dd = clk->dpll_data;

        if (!dd->autoidle_reg)
                return;

        /*
         * REVISIT: CORE DPLL can optionally enter low-power bypass
         * by writing 0x5 instead of 0x1.  Add some mechanism to
         * optionally enter this mode.
         */
        v = __raw_readl(dd->autoidle_reg);
        v &= ~dd->autoidle_mask;
        v |= DPLL_AUTOIDLE_LOW_POWER_STOP << __ffs(dd->autoidle_mask);
        __raw_writel(v, dd->autoidle_reg);

}

/**
 * omap3_dpll_deny_idle - prevent DPLL from automatically idling
 * @clk: struct clk * of the DPLL to operate on
 *
 * Disable DPLL automatic idle control.  No return value.
 */
void omap3_dpll_deny_idle(struct clk_hw_omap *clk)
{
        const struct dpll_data *dd;
        u32 v;

        if (!clk || !clk->dpll_data)
                return;

        dd = clk->dpll_data;

        if (!dd->autoidle_reg)
                return;

        v = __raw_readl(dd->autoidle_reg);
        v &= ~dd->autoidle_mask;
        v |= DPLL_AUTOIDLE_DISABLE << __ffs(dd->autoidle_mask);
        __raw_writel(v, dd->autoidle_reg);

}

/* Clock control for DPLL outputs */

/**
 * omap3_clkoutx2_recalc - recalculate DPLL X2 output virtual clock rate
 * @clk: DPLL output struct clk
 *
 * Using parent clock DPLL data, look up DPLL state.  If locked, set our
 * rate to the dpll_clk * 2; otherwise, just use dpll_clk.
 */
unsigned long omap3_clkoutx2_recalc(struct clk_hw *hw,
                                    unsigned long parent_rate)
{
        const struct dpll_data *dd;
        unsigned long rate;
        u32 v;
        struct clk_hw_omap *pclk = NULL;
        struct clk *parent;

        /* Walk up the parents of clk, looking for a DPLL */
        do {
                do {
                        parent = __clk_get_parent(hw->clk);
                        hw = __clk_get_hw(parent);
                } while (hw && (__clk_get_flags(hw->clk) & CLK_IS_BASIC));
                if (!hw)
                        break;
                pclk = to_clk_hw_omap(hw);
        } while (pclk && !pclk->dpll_data);

        /* clk does not have a DPLL as a parent?  error in the clock data */
        if (!pclk) {
                WARN_ON(1);
                return 0;
        }

        dd = pclk->dpll_data;

        WARN_ON(!dd->enable_mask);

        v = __raw_readl(dd->control_reg) & dd->enable_mask;
        v >>= __ffs(dd->enable_mask);
        if ((v != OMAP3XXX_EN_DPLL_LOCKED) || (dd->flags & DPLL_J_TYPE))
                rate = parent_rate;
        else
                rate = parent_rate * 2;
        return rate;
}

/* OMAP3/4 non-CORE DPLL clkops */
const struct clk_hw_omap_ops clkhwops_omap3_dpll = {
        .allow_idle     = omap3_dpll_allow_idle,
        .deny_idle      = omap3_dpll_deny_idle,
};