/*
 * AM33XX PRM functions
 *
 * Copyright (C) 2011-2012 Texas Instruments Incorporated - https://www.ti.com/
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation version 2.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/io.h>

#include "powerdomain.h"
#include "prm33xx.h"
#include "prm-regbits-33xx.h"

#define AM33XX_PRM_RSTCTRL_OFFSET               0x0000

#define AM33XX_RST_GLOBAL_WARM_SW_MASK          (1 << 0)

/* Read a register in a PRM instance */
static u32 am33xx_prm_read_reg(s16 inst, u16 idx)
{
        return readl_relaxed(prm_base.va + inst + idx);
}

/* Write into a register in a PRM instance */
static void am33xx_prm_write_reg(u32 val, s16 inst, u16 idx)
{
        writel_relaxed(val, prm_base.va + inst + idx);
}

/* Read-modify-write a register in PRM. Caller must lock */
static u32 am33xx_prm_rmw_reg_bits(u32 mask, u32 bits, s16 inst, s16 idx)
{
        u32 v;

        v = am33xx_prm_read_reg(inst, idx);
        v &= ~mask;
        v |= bits;
        am33xx_prm_write_reg(v, inst, idx);

        return v;
}

/**
 * am33xx_prm_is_hardreset_asserted - read the HW reset line state of
 * submodules contained in the hwmod module
 * @shift: register bit shift corresponding to the reset line to check
 * @part: PRM partition, ignored for AM33xx
 * @inst: CM instance register offset (*_INST macro)
 * @rstctrl_offs: RM_RSTCTRL register address offset for this module
 *
 * Returns 1 if the (sub)module hardreset line is currently asserted,
 * 0 if the (sub)module hardreset line is not currently asserted, or
 * -EINVAL upon parameter error.
 */
static int am33xx_prm_is_hardreset_asserted(u8 shift, u8 part, s16 inst,
                                            u16 rstctrl_offs)
{
        u32 v;

        v = am33xx_prm_read_reg(inst, rstctrl_offs);
        v &= 1 << shift;
        v >>= shift;

        return v;
}

/**
 * am33xx_prm_assert_hardreset - assert the HW reset line of a submodule
 * @shift: register bit shift corresponding to the reset line to assert
 * @part: CM partition, ignored for AM33xx
 * @inst: CM instance register offset (*_INST macro)
 * @rstctrl_reg: RM_RSTCTRL register address for this module
 *
 * Some IPs like dsp, ipu or iva contain processors that require an HW
 * reset line to be asserted / deasserted in order to fully enable the
 * IP.  These modules may have multiple hard-reset lines that reset
 * different 'submodules' inside the IP block.  This function will
 * place the submodule into reset.  Returns 0 upon success or -EINVAL
 * upon an argument error.
 */
static int am33xx_prm_assert_hardreset(u8 shift, u8 part, s16 inst,
                                       u16 rstctrl_offs)
{
        u32 mask = 1 << shift;

        am33xx_prm_rmw_reg_bits(mask, mask, inst, rstctrl_offs);

        return 0;
}

/**
 * am33xx_prm_deassert_hardreset - deassert a submodule hardreset line and
 * wait
 * @shift: register bit shift corresponding to the reset line to deassert
 * @st_shift: reset status register bit shift corresponding to the reset line
 * @part: PRM partition, not used for AM33xx
 * @inst: CM instance register offset (*_INST macro)
 * @rstctrl_reg: RM_RSTCTRL register address for this module
 * @rstst_reg: RM_RSTST register address for this module
 *
 * Some IPs like dsp, ipu or iva contain processors that require an HW
 * reset line to be asserted / deasserted in order to fully enable the
 * IP.  These modules may have multiple hard-reset lines that reset
 * different 'submodules' inside the IP block.  This function will
 * take the submodule out of reset and wait until the PRCM indicates
 * that the reset has completed before returning.  Returns 0 upon success or
 * -EINVAL upon an argument error, -EEXIST if the submodule was already out
 * of reset, or -EBUSY if the submodule did not exit reset promptly.
 */
static int am33xx_prm_deassert_hardreset(u8 shift, u8 st_shift, u8 part,
                                         s16 inst, u16 rstctrl_offs,
                                         u16 rstst_offs)
{
        int c;
        u32 mask = 1 << st_shift;

        /* Check the current status to avoid  de-asserting the line twice */
        if (am33xx_prm_is_hardreset_asserted(shift, 0, inst, rstctrl_offs) == 0)
                return -EEXIST;

        /* Clear the reset status by writing 1 to the status bit */
        am33xx_prm_rmw_reg_bits(0xffffffff, mask, inst, rstst_offs);

        /* de-assert the reset control line */
        mask = 1 << shift;

        am33xx_prm_rmw_reg_bits(mask, 0, inst, rstctrl_offs);

        /* wait the status to be set */
        omap_test_timeout(am33xx_prm_is_hardreset_asserted(st_shift, 0, inst,
                                                           rstst_offs),
                          MAX_MODULE_HARDRESET_WAIT, c);

        return (c == MAX_MODULE_HARDRESET_WAIT) ? -EBUSY : 0;
}

static int am33xx_pwrdm_set_next_pwrst(struct powerdomain *pwrdm, u8 pwrst)
{
        am33xx_prm_rmw_reg_bits(OMAP_POWERSTATE_MASK,
                                (pwrst << OMAP_POWERSTATE_SHIFT),
                                pwrdm->prcm_offs, pwrdm->pwrstctrl_offs);
        return 0;
}

static int am33xx_pwrdm_read_next_pwrst(struct powerdomain *pwrdm)
{
        u32 v;

        v = am33xx_prm_read_reg(pwrdm->prcm_offs,  pwrdm->pwrstctrl_offs);
        v &= OMAP_POWERSTATE_MASK;
        v >>= OMAP_POWERSTATE_SHIFT;

        return v;
}

static int am33xx_pwrdm_read_pwrst(struct powerdomain *pwrdm)
{
        u32 v;

        v = am33xx_prm_read_reg(pwrdm->prcm_offs, pwrdm->pwrstst_offs);
        v &= OMAP_POWERSTATEST_MASK;
        v >>= OMAP_POWERSTATEST_SHIFT;

        return v;
}

static int am33xx_pwrdm_set_lowpwrstchange(struct powerdomain *pwrdm)
{
        am33xx_prm_rmw_reg_bits(AM33XX_LOWPOWERSTATECHANGE_MASK,
                                (1 << AM33XX_LOWPOWERSTATECHANGE_SHIFT),
                                pwrdm->prcm_offs, pwrdm->pwrstctrl_offs);
        return 0;
}

static int am33xx_pwrdm_clear_all_prev_pwrst(struct powerdomain *pwrdm)
{
        am33xx_prm_rmw_reg_bits(AM33XX_LASTPOWERSTATEENTERED_MASK,
                                AM33XX_LASTPOWERSTATEENTERED_MASK,
                                pwrdm->prcm_offs, pwrdm->pwrstst_offs);
        return 0;
}

static int am33xx_pwrdm_set_logic_retst(struct powerdomain *pwrdm, u8 pwrst)
{
        u32 m;

        m = pwrdm->logicretstate_mask;
        if (!m)
                return -EINVAL;

        am33xx_prm_rmw_reg_bits(m, (pwrst << __ffs(m)),
                                pwrdm->prcm_offs, pwrdm->pwrstctrl_offs);

        return 0;
}

static int am33xx_pwrdm_read_logic_pwrst(struct powerdomain *pwrdm)
{
        u32 v;

        v = am33xx_prm_read_reg(pwrdm->prcm_offs, pwrdm->pwrstst_offs);
        v &= AM33XX_LOGICSTATEST_MASK;
        v >>= AM33XX_LOGICSTATEST_SHIFT;

        return v;
}

static int am33xx_pwrdm_read_logic_retst(struct powerdomain *pwrdm)
{
        u32 v, m;

        m = pwrdm->logicretstate_mask;
        if (!m)
                return -EINVAL;

        v = am33xx_prm_read_reg(pwrdm->prcm_offs, pwrdm->pwrstctrl_offs);
        v &= m;
        v >>= __ffs(m);

        return v;
}

static int am33xx_pwrdm_set_mem_onst(struct powerdomain *pwrdm, u8 bank,
                u8 pwrst)
{
        u32 m;

        m = pwrdm->mem_on_mask[bank];
        if (!m)
                return -EINVAL;

        am33xx_prm_rmw_reg_bits(m, (pwrst << __ffs(m)),
                                pwrdm->prcm_offs, pwrdm->pwrstctrl_offs);

        return 0;
}

static int am33xx_pwrdm_set_mem_retst(struct powerdomain *pwrdm, u8 bank,
                                        u8 pwrst)
{
        u32 m;

        m = pwrdm->mem_ret_mask[bank];
        if (!m)
                return -EINVAL;

        am33xx_prm_rmw_reg_bits(m, (pwrst << __ffs(m)),
                                pwrdm->prcm_offs, pwrdm->pwrstctrl_offs);

        return 0;
}

static int am33xx_pwrdm_read_mem_pwrst(struct powerdomain *pwrdm, u8 bank)
{
        u32 m, v;

        m = pwrdm->mem_pwrst_mask[bank];
        if (!m)
                return -EINVAL;

        v = am33xx_prm_read_reg(pwrdm->prcm_offs, pwrdm->pwrstst_offs);
        v &= m;
        v >>= __ffs(m);

        return v;
}

static int am33xx_pwrdm_read_mem_retst(struct powerdomain *pwrdm, u8 bank)
{
        u32 m, v;

        m = pwrdm->mem_retst_mask[bank];
        if (!m)
                return -EINVAL;

        v = am33xx_prm_read_reg(pwrdm->prcm_offs, pwrdm->pwrstctrl_offs);
        v &= m;
        v >>= __ffs(m);

        return v;
}

static int am33xx_pwrdm_wait_transition(struct powerdomain *pwrdm)
{
        u32 c = 0;

        /*
         * REVISIT: pwrdm_wait_transition() may be better implemented
         * via a callback and a periodic timer check -- how long do we expect
         * powerdomain transitions to take?
         */

        /* XXX Is this udelay() value meaningful? */
        while ((am33xx_prm_read_reg(pwrdm->prcm_offs, pwrdm->pwrstst_offs)
                        & OMAP_INTRANSITION_MASK) &&
                        (c++ < PWRDM_TRANSITION_BAILOUT))
                udelay(1);

        if (c > PWRDM_TRANSITION_BAILOUT) {
                pr_err("powerdomain: %s: waited too long to complete transition\n",
                       pwrdm->name);
                return -EAGAIN;
        }

        pr_debug("powerdomain: completed transition in %d loops\n", c);

        return 0;
}

static int am33xx_check_vcvp(void)
{
        /* No VC/VP on am33xx devices */
        return 0;
}

/**
 * am33xx_prm_global_warm_sw_reset - reboot the device via warm reset
 *
 * Immediately reboots the device through warm reset.
 */
static void am33xx_prm_global_warm_sw_reset(void)
{
        am33xx_prm_rmw_reg_bits(AM33XX_RST_GLOBAL_WARM_SW_MASK,
                                AM33XX_RST_GLOBAL_WARM_SW_MASK,
                                AM33XX_PRM_DEVICE_MOD,
                                AM33XX_PRM_RSTCTRL_OFFSET);

        /* OCP barrier */
        (void)am33xx_prm_read_reg(AM33XX_PRM_DEVICE_MOD,
                                  AM33XX_PRM_RSTCTRL_OFFSET);
}

static void am33xx_pwrdm_save_context(struct powerdomain *pwrdm)
{
        pwrdm->context = am33xx_prm_read_reg(pwrdm->prcm_offs,
                                                pwrdm->pwrstctrl_offs);
        /*
         * Do not save LOWPOWERSTATECHANGE, writing a 1 indicates a request,
         * reading back a 1 indicates a request in progress.
         */
        pwrdm->context &= ~AM33XX_LOWPOWERSTATECHANGE_MASK;
}

static void am33xx_pwrdm_restore_context(struct powerdomain *pwrdm)
{
        int st, ctrl;

        st = am33xx_prm_read_reg(pwrdm->prcm_offs,
                                 pwrdm->pwrstst_offs);

        am33xx_prm_write_reg(pwrdm->context, pwrdm->prcm_offs,
                             pwrdm->pwrstctrl_offs);

        /* Make sure we only wait for a transition if there is one */
        st &= OMAP_POWERSTATEST_MASK;
        ctrl = OMAP_POWERSTATEST_MASK & pwrdm->context;

        if (st != ctrl)
                am33xx_pwrdm_wait_transition(pwrdm);
}

struct pwrdm_ops am33xx_pwrdm_operations = {
        .pwrdm_set_next_pwrst           = am33xx_pwrdm_set_next_pwrst,
        .pwrdm_read_next_pwrst          = am33xx_pwrdm_read_next_pwrst,
        .pwrdm_read_pwrst               = am33xx_pwrdm_read_pwrst,
        .pwrdm_set_logic_retst          = am33xx_pwrdm_set_logic_retst,
        .pwrdm_read_logic_pwrst         = am33xx_pwrdm_read_logic_pwrst,
        .pwrdm_read_logic_retst         = am33xx_pwrdm_read_logic_retst,
        .pwrdm_clear_all_prev_pwrst     = am33xx_pwrdm_clear_all_prev_pwrst,
        .pwrdm_set_lowpwrstchange       = am33xx_pwrdm_set_lowpwrstchange,
        .pwrdm_read_mem_pwrst           = am33xx_pwrdm_read_mem_pwrst,
        .pwrdm_read_mem_retst           = am33xx_pwrdm_read_mem_retst,
        .pwrdm_set_mem_onst             = am33xx_pwrdm_set_mem_onst,
        .pwrdm_set_mem_retst            = am33xx_pwrdm_set_mem_retst,
        .pwrdm_wait_transition          = am33xx_pwrdm_wait_transition,
        .pwrdm_has_voltdm               = am33xx_check_vcvp,
        .pwrdm_save_context             = am33xx_pwrdm_save_context,
        .pwrdm_restore_context          = am33xx_pwrdm_restore_context,
};

static struct prm_ll_data am33xx_prm_ll_data = {
        .assert_hardreset               = am33xx_prm_assert_hardreset,
        .deassert_hardreset             = am33xx_prm_deassert_hardreset,
        .is_hardreset_asserted          = am33xx_prm_is_hardreset_asserted,
        .reset_system                   = am33xx_prm_global_warm_sw_reset,
};

int __init am33xx_prm_init(const struct omap_prcm_init_data *data)
{
        return prm_register(&am33xx_prm_ll_data);
}

static void __exit am33xx_prm_exit(void)
{
        prm_unregister(&am33xx_prm_ll_data);
}
__exitcall(am33xx_prm_exit);