/*      $Id: at91pmc.c,v 1.8 2020/02/24 12:38:57 rin Exp $      */
/*      $NetBSD: at91pmc.c,v 1.8 2020/02/24 12:38:57 rin Exp $  */

/*
 * Copyright (c) 2007 Embedtronics Oy
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: at91pmc.c,v 1.8 2020/02/24 12:38:57 rin Exp $");

#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/time.h>
#include <sys/device.h>

#include <sys/bus.h>
#include <machine/intr.h>

#include <arm/cpufunc.h>

#include <arm/at91/at91reg.h>
#include <arm/at91/at91var.h>
#include <arm/at91/at91pmcreg.h>
#include <arm/at91/at91pmcvar.h>

#define SLOW_CLOCK      32768LU

void
at91pmc_get_clocks(struct at91bus_clocks *clocks)
{
        uint64_t                mclk, pllaclk, pllbclk, pclk, mstclk;
        uint32_t                reg;

        if (!((reg = PMCREG(PMC_MOR)) & PMC_MOR_MOSCEN))
                panic("%s: main oscillator not enabled (MOR=%#X)", __FUNCTION__, reg);

        if (!((reg = PMCREG(PMC_MCFR)) & PMC_MCFR_MAINRDY))
                panic("%s: main oscillator not ready (MCFR=%#X)", __FUNCTION__, reg);

        mclk  = ((reg & PMC_MCFR_MAINF) * SLOW_CLOCK) / 16U;

        // try to guess some nice MHz value
        if (((mclk / 1000) % 1000) >= 990) {
          mclk += 1000000U - (mclk % 1000000U);
        } else if (((mclk / 1000) % 1000) <= 10) {
          mclk -= (mclk % 1000000U);
        }

        PMCREG(PMC_PLLICPR) = PMC_PLLICPR_ICPPLLA | PMC_PLLICPR_ICPPLLB;

        reg = PMCREG(PMC_PLLAR); pllaclk = 0;
        if (reg & PMC_PLL_DIV) {
                pllaclk = mclk * (((reg & PMC_PLL_MUL) >> PMC_PLL_MUL_SHIFT) + 1);
                pllaclk /= (reg & PMC_PLL_DIV) >> PMC_PLL_DIV_SHIFT;
        }

        reg = PMCREG(PMC_PLLBR); pllbclk = 0;
        if (reg & PMC_PLL_DIV) {
                pllbclk = mclk * (((reg & PMC_PLL_MUL) >> PMC_PLL_MUL_SHIFT) + 1);
                pllbclk /= (reg & PMC_PLL_DIV) >> PMC_PLL_DIV_SHIFT;
                if (reg & PMC_PLLBR_USB_96M) {
                        pllbclk /= 2;
                }
        }

        reg = PMCREG(PMC_MCKR);
        switch ((reg & PMC_MCKR_CSS)) {
        case PMC_MCKR_CSS_SLOW_CLK:
          pclk = SLOW_CLOCK;
          break;
        default:
        case PMC_MCKR_CSS_MAIN_CLK:
          pclk = mclk;
          break;
        case PMC_MCKR_CSS_PLLA:
          pclk = pllaclk;
          break;
        case PMC_MCKR_CSS_PLLB:
          pclk = pllbclk;
          break;
        }
        pclk >>= (reg & PMC_MCKR_PRES) >> PMC_MCKR_PRES_SHIFT;
        mstclk = pclk / (((reg & PMC_MCKR_MDIV) >> PMC_MCKR_MDIV_SHIFT) + 1);

        clocks->slow = SLOW_CLOCK;
        clocks->main = mclk;
        clocks->cpu = pclk;
        clocks->master = mstclk;
        clocks->plla = pllaclk;
        clocks->pllb = pllbclk;
}


#define PID_COUNT       32
static int pid_enable_count[PID_COUNT] = {0};

void
at91pmc_peripheral_clock(int pid, int enable)
{
        int s;

        if (pid < 0 || pid >= PID_COUNT)
                panic("%s: pid %d out of range", __FUNCTION__, pid);

        s = splhigh();

        if (enable) {
                pid_enable_count[pid]++;
                PMCREG(PMC_PCER) = (1U << pid);
        } else {
                if (--pid_enable_count[pid] < 0)
                        panic("%s: pid %d enable count got negative (%d)",
                              __FUNCTION__, pid, pid_enable_count[pid]);
                if (pid_enable_count[pid] == 0)
                        PMCREG(PMC_PCDR) = (1U << pid);
        }

        splx(s);

        if (enable) {
                int c;
                for (c = 0; c < 10000; c++) {
                  __insn_barrier();
                }
        }
}