// SPDX-License-Identifier: GPL-2.0-only
/*
 * Atmel SMC (Static Memory Controller) helper functions.
 *
 * Copyright (C) 2017 Atmel
 * Copyright (C) 2017 Free Electrons
 *
 * Author: Boris Brezillon <boris.brezillon@free-electrons.com>
 */

#include <linux/mfd/syscon/atmel-smc.h>
#include <linux/string.h>

/**
 * atmel_smc_cs_conf_init - initialize a SMC CS conf
 * @conf: the SMC CS conf to initialize
 *
 * Set all fields to 0 so that one can start defining a new config.
 */
void atmel_smc_cs_conf_init(struct atmel_smc_cs_conf *conf)
{
        memset(conf, 0, sizeof(*conf));
}
EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_init);

/**
 * atmel_smc_cs_encode_ncycles - encode a number of MCK clk cycles in the
 *                               format expected by the SMC engine
 * @ncycles: number of MCK clk cycles
 * @msbpos: position of the MSB part of the timing field
 * @msbwidth: width of the MSB part of the timing field
 * @msbfactor: factor applied to the MSB
 * @encodedval: param used to store the encoding result
 *
 * This function encodes the @ncycles value as described in the datasheet
 * (section "SMC Setup/Pulse/Cycle/Timings Register"). This is a generic
 * helper which called with different parameter depending on the encoding
 * scheme.
 *
 * If the @ncycles value is too big to be encoded, -ERANGE is returned and
 * the encodedval is contains the maximum val. Otherwise, 0 is returned.
 */
static int atmel_smc_cs_encode_ncycles(unsigned int ncycles,
                                       unsigned int msbpos,
                                       unsigned int msbwidth,
                                       unsigned int msbfactor,
                                       unsigned int *encodedval)
{
        unsigned int lsbmask = GENMASK(msbpos - 1, 0);
        unsigned int msbmask = GENMASK(msbwidth - 1, 0);
        unsigned int msb, lsb;
        int ret = 0;

        msb = ncycles / msbfactor;
        lsb = ncycles % msbfactor;

        if (lsb > lsbmask) {
                lsb = 0;
                msb++;
        }

        /*
         * Let's just put the maximum we can if the requested setting does
         * not fit in the register field.
         * We still return -ERANGE in case the caller cares.
         */
        if (msb > msbmask) {
                msb = msbmask;
                lsb = lsbmask;
                ret = -ERANGE;
        }

        *encodedval = (msb << msbpos) | lsb;

        return ret;
}

/**
 * atmel_smc_cs_conf_set_timing - set the SMC CS conf Txx parameter to a
 *                                specific value
 * @conf: SMC CS conf descriptor
 * @shift: the position of the Txx field in the TIMINGS register
 * @ncycles: value (expressed in MCK clk cycles) to assign to this Txx
 *           parameter
 *
 * This function encodes the @ncycles value as described in the datasheet
 * (section "SMC Timings Register"), and then stores the result in the
 * @conf->timings field at @shift position.
 *
 * Returns -EINVAL if shift is invalid, -ERANGE if ncycles does not fit in
 * the field, and 0 otherwise.
 */
int atmel_smc_cs_conf_set_timing(struct atmel_smc_cs_conf *conf,
                                 unsigned int shift, unsigned int ncycles)
{
        unsigned int val;
        int ret;

        if (shift != ATMEL_HSMC_TIMINGS_TCLR_SHIFT &&
            shift != ATMEL_HSMC_TIMINGS_TADL_SHIFT &&
            shift != ATMEL_HSMC_TIMINGS_TAR_SHIFT &&
            shift != ATMEL_HSMC_TIMINGS_TRR_SHIFT &&
            shift != ATMEL_HSMC_TIMINGS_TWB_SHIFT)
                return -EINVAL;

        /*
         * The formula described in atmel datasheets (section "HSMC Timings
         * Register"):
         *
         * ncycles = (Txx[3] * 64) + Txx[2:0]
         */
        ret = atmel_smc_cs_encode_ncycles(ncycles, 3, 1, 64, &val);
        conf->timings &= ~GENMASK(shift + 3, shift);
        conf->timings |= val << shift;

        return ret;
}
EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_set_timing);

/**
 * atmel_smc_cs_conf_set_setup - set the SMC CS conf xx_SETUP parameter to a
 *                               specific value
 * @conf: SMC CS conf descriptor
 * @shift: the position of the xx_SETUP field in the SETUP register
 * @ncycles: value (expressed in MCK clk cycles) to assign to this xx_SETUP
 *           parameter
 *
 * This function encodes the @ncycles value as described in the datasheet
 * (section "SMC Setup Register"), and then stores the result in the
 * @conf->setup field at @shift position.
 *
 * Returns -EINVAL if @shift is invalid, -ERANGE if @ncycles does not fit in
 * the field, and 0 otherwise.
 */
int atmel_smc_cs_conf_set_setup(struct atmel_smc_cs_conf *conf,
                                unsigned int shift, unsigned int ncycles)
{
        unsigned int val;
        int ret;

        if (shift != ATMEL_SMC_NWE_SHIFT && shift != ATMEL_SMC_NCS_WR_SHIFT &&
            shift != ATMEL_SMC_NRD_SHIFT && shift != ATMEL_SMC_NCS_RD_SHIFT)
                return -EINVAL;

        /*
         * The formula described in atmel datasheets (section "SMC Setup
         * Register"):
         *
         * ncycles = (128 * xx_SETUP[5]) + xx_SETUP[4:0]
         */
        ret = atmel_smc_cs_encode_ncycles(ncycles, 5, 1, 128, &val);
        conf->setup &= ~GENMASK(shift + 7, shift);
        conf->setup |= val << shift;

        return ret;
}
EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_set_setup);

/**
 * atmel_smc_cs_conf_set_pulse - set the SMC CS conf xx_PULSE parameter to a
 *                               specific value
 * @conf: SMC CS conf descriptor
 * @shift: the position of the xx_PULSE field in the PULSE register
 * @ncycles: value (expressed in MCK clk cycles) to assign to this xx_PULSE
 *           parameter
 *
 * This function encodes the @ncycles value as described in the datasheet
 * (section "SMC Pulse Register"), and then stores the result in the
 * @conf->setup field at @shift position.
 *
 * Returns -EINVAL if @shift is invalid, -ERANGE if @ncycles does not fit in
 * the field, and 0 otherwise.
 */
int atmel_smc_cs_conf_set_pulse(struct atmel_smc_cs_conf *conf,
                                unsigned int shift, unsigned int ncycles)
{
        unsigned int val;
        int ret;

        if (shift != ATMEL_SMC_NWE_SHIFT && shift != ATMEL_SMC_NCS_WR_SHIFT &&
            shift != ATMEL_SMC_NRD_SHIFT && shift != ATMEL_SMC_NCS_RD_SHIFT)
                return -EINVAL;

        /*
         * The formula described in atmel datasheets (section "SMC Pulse
         * Register"):
         *
         * ncycles = (256 * xx_PULSE[6]) + xx_PULSE[5:0]
         */
        ret = atmel_smc_cs_encode_ncycles(ncycles, 6, 1, 256, &val);
        conf->pulse &= ~GENMASK(shift + 7, shift);
        conf->pulse |= val << shift;

        return ret;
}
EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_set_pulse);

/**
 * atmel_smc_cs_conf_set_cycle - set the SMC CS conf xx_CYCLE parameter to a
 *                               specific value
 * @conf: SMC CS conf descriptor
 * @shift: the position of the xx_CYCLE field in the CYCLE register
 * @ncycles: value (expressed in MCK clk cycles) to assign to this xx_CYCLE
 *           parameter
 *
 * This function encodes the @ncycles value as described in the datasheet
 * (section "SMC Cycle Register"), and then stores the result in the
 * @conf->setup field at @shift position.
 *
 * Returns -EINVAL if @shift is invalid, -ERANGE if @ncycles does not fit in
 * the field, and 0 otherwise.
 */
int atmel_smc_cs_conf_set_cycle(struct atmel_smc_cs_conf *conf,
                                unsigned int shift, unsigned int ncycles)
{
        unsigned int val;
        int ret;

        if (shift != ATMEL_SMC_NWE_SHIFT && shift != ATMEL_SMC_NRD_SHIFT)
                return -EINVAL;

        /*
         * The formula described in atmel datasheets (section "SMC Cycle
         * Register"):
         *
         * ncycles = (xx_CYCLE[8:7] * 256) + xx_CYCLE[6:0]
         */
        ret = atmel_smc_cs_encode_ncycles(ncycles, 7, 2, 256, &val);
        conf->cycle &= ~GENMASK(shift + 15, shift);
        conf->cycle |= val << shift;

        return ret;
}
EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_set_cycle);

/**
 * atmel_smc_cs_conf_apply - apply an SMC CS conf
 * @regmap: the SMC regmap
 * @cs: the CS id
 * @conf: the SMC CS conf to apply
 *
 * Applies an SMC CS configuration.
 * Only valid on at91sam9/avr32 SoCs.
 */
void atmel_smc_cs_conf_apply(struct regmap *regmap, int cs,
                             const struct atmel_smc_cs_conf *conf)
{
        regmap_write(regmap, ATMEL_SMC_SETUP(cs), conf->setup);
        regmap_write(regmap, ATMEL_SMC_PULSE(cs), conf->pulse);
        regmap_write(regmap, ATMEL_SMC_CYCLE(cs), conf->cycle);
        regmap_write(regmap, ATMEL_SMC_MODE(cs), conf->mode);
}
EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_apply);

/**
 * atmel_hsmc_cs_conf_apply - apply an SMC CS conf
 * @regmap: the HSMC regmap
 * @cs: the CS id
 * @layout: the layout of registers
 * @conf: the SMC CS conf to apply
 *
 * Applies an SMC CS configuration.
 * Only valid on post-sama5 SoCs.
 */
void atmel_hsmc_cs_conf_apply(struct regmap *regmap,
                              const struct atmel_hsmc_reg_layout *layout,
                              int cs, const struct atmel_smc_cs_conf *conf)
{
        regmap_write(regmap, ATMEL_HSMC_SETUP(layout, cs), conf->setup);
        regmap_write(regmap, ATMEL_HSMC_PULSE(layout, cs), conf->pulse);
        regmap_write(regmap, ATMEL_HSMC_CYCLE(layout, cs), conf->cycle);
        regmap_write(regmap, ATMEL_HSMC_TIMINGS(layout, cs), conf->timings);
        regmap_write(regmap, ATMEL_HSMC_MODE(layout, cs), conf->mode);
}
EXPORT_SYMBOL_GPL(atmel_hsmc_cs_conf_apply);

/**
 * atmel_smc_cs_conf_get - retrieve the current SMC CS conf
 * @regmap: the SMC regmap
 * @cs: the CS id
 * @conf: the SMC CS conf object to store the current conf
 *
 * Retrieve the SMC CS configuration.
 * Only valid on at91sam9/avr32 SoCs.
 */
void atmel_smc_cs_conf_get(struct regmap *regmap, int cs,
                           struct atmel_smc_cs_conf *conf)
{
        regmap_read(regmap, ATMEL_SMC_SETUP(cs), &conf->setup);
        regmap_read(regmap, ATMEL_SMC_PULSE(cs), &conf->pulse);
        regmap_read(regmap, ATMEL_SMC_CYCLE(cs), &conf->cycle);
        regmap_read(regmap, ATMEL_SMC_MODE(cs), &conf->mode);
}
EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_get);

/**
 * atmel_hsmc_cs_conf_get - retrieve the current SMC CS conf
 * @regmap: the HSMC regmap
 * @cs: the CS id
 * @layout: the layout of registers
 * @conf: the SMC CS conf object to store the current conf
 *
 * Retrieve the SMC CS configuration.
 * Only valid on post-sama5 SoCs.
 */
void atmel_hsmc_cs_conf_get(struct regmap *regmap,
                            const struct atmel_hsmc_reg_layout *layout,
                            int cs, struct atmel_smc_cs_conf *conf)
{
        regmap_read(regmap, ATMEL_HSMC_SETUP(layout, cs), &conf->setup);
        regmap_read(regmap, ATMEL_HSMC_PULSE(layout, cs), &conf->pulse);
        regmap_read(regmap, ATMEL_HSMC_CYCLE(layout, cs), &conf->cycle);
        regmap_read(regmap, ATMEL_HSMC_TIMINGS(layout, cs), &conf->timings);
        regmap_read(regmap, ATMEL_HSMC_MODE(layout, cs), &conf->mode);
}
EXPORT_SYMBOL_GPL(atmel_hsmc_cs_conf_get);

static const struct atmel_hsmc_reg_layout sama5d3_reg_layout = {
        .timing_regs_offset = 0x600,
};

static const struct atmel_hsmc_reg_layout sama5d2_reg_layout = {
        .timing_regs_offset = 0x700,
};

static const struct of_device_id atmel_smc_ids[] = {
        { .compatible = "atmel,at91sam9260-smc", .data = NULL },
        { .compatible = "atmel,sama5d3-smc", .data = &sama5d3_reg_layout },
        { .compatible = "atmel,sama5d2-smc", .data = &sama5d2_reg_layout },
        { /* sentinel */ },
};

/**
 * atmel_hsmc_get_reg_layout - retrieve the layout of HSMC registers
 * @np: the HSMC regmap
 *
 * Retrieve the layout of HSMC registers.
 *
 * Returns NULL in case of SMC, a struct atmel_hsmc_reg_layout pointer
 * in HSMC case, otherwise ERR_PTR(-EINVAL).
 */
const struct atmel_hsmc_reg_layout *
atmel_hsmc_get_reg_layout(struct device_node *np)
{
        const struct of_device_id *match;

        match = of_match_node(atmel_smc_ids, np);

        return match ? match->data : ERR_PTR(-EINVAL);
}
EXPORT_SYMBOL_GPL(atmel_hsmc_get_reg_layout);