root/drivers/memory/atmel-ebi.c
// SPDX-License-Identifier: GPL-2.0
/*
 * EBI driver for Atmel chips
 * inspired by the fsl weim bus driver
 *
 * Copyright (C) 2013 Jean-Jacques Hiblot <jjhiblot@traphandler.com>
 */

#include <linux/cleanup.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/mfd/syscon.h>
#include <linux/mfd/syscon/atmel-matrix.h>
#include <linux/mfd/syscon/atmel-smc.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <soc/at91/atmel-sfr.h>

#define AT91_EBI_NUM_CS         8

struct atmel_ebi_dev_config {
        int cs;
        struct atmel_smc_cs_conf smcconf;
};

struct atmel_ebi;

struct atmel_ebi_dev {
        struct list_head node;
        struct atmel_ebi *ebi;
        u32 mode;
        int numcs;
        struct atmel_ebi_dev_config configs[] __counted_by(numcs);
};

struct atmel_ebi_caps {
        unsigned int available_cs;
        unsigned int ebi_csa_offs;
        const char *regmap_name;
        void (*get_config)(struct atmel_ebi_dev *ebid,
                           struct atmel_ebi_dev_config *conf);
        int (*xlate_config)(struct atmel_ebi_dev *ebid,
                            struct device_node *configs_np,
                            struct atmel_ebi_dev_config *conf);
        void (*apply_config)(struct atmel_ebi_dev *ebid,
                             struct atmel_ebi_dev_config *conf);
};

struct atmel_ebi {
        struct clk *clk;
        struct regmap *regmap;
        struct  {
                struct regmap *regmap;
                struct clk *clk;
                const struct atmel_hsmc_reg_layout *layout;
        } smc;

        struct device *dev;
        const struct atmel_ebi_caps *caps;
        struct list_head devs;
};

struct atmel_smc_timing_xlate {
        const char *name;
        int (*converter)(struct atmel_smc_cs_conf *conf,
                         unsigned int shift, unsigned int nycles);
        unsigned int shift;
};

#define ATMEL_SMC_SETUP_XLATE(nm, pos)  \
        { .name = nm, .converter = atmel_smc_cs_conf_set_setup, .shift = pos}

#define ATMEL_SMC_PULSE_XLATE(nm, pos)  \
        { .name = nm, .converter = atmel_smc_cs_conf_set_pulse, .shift = pos}

#define ATMEL_SMC_CYCLE_XLATE(nm, pos)  \
        { .name = nm, .converter = atmel_smc_cs_conf_set_cycle, .shift = pos}

static void at91sam9_ebi_get_config(struct atmel_ebi_dev *ebid,
                                    struct atmel_ebi_dev_config *conf)
{
        atmel_smc_cs_conf_get(ebid->ebi->smc.regmap, conf->cs,
                              &conf->smcconf);
}

static void sama5_ebi_get_config(struct atmel_ebi_dev *ebid,
                                 struct atmel_ebi_dev_config *conf)
{
        atmel_hsmc_cs_conf_get(ebid->ebi->smc.regmap, ebid->ebi->smc.layout,
                               conf->cs, &conf->smcconf);
}

static const struct atmel_smc_timing_xlate timings_xlate_table[] = {
        ATMEL_SMC_SETUP_XLATE("atmel,smc-ncs-rd-setup-ns",
                              ATMEL_SMC_NCS_RD_SHIFT),
        ATMEL_SMC_SETUP_XLATE("atmel,smc-ncs-wr-setup-ns",
                              ATMEL_SMC_NCS_WR_SHIFT),
        ATMEL_SMC_SETUP_XLATE("atmel,smc-nrd-setup-ns", ATMEL_SMC_NRD_SHIFT),
        ATMEL_SMC_SETUP_XLATE("atmel,smc-nwe-setup-ns", ATMEL_SMC_NWE_SHIFT),
        ATMEL_SMC_PULSE_XLATE("atmel,smc-ncs-rd-pulse-ns",
                              ATMEL_SMC_NCS_RD_SHIFT),
        ATMEL_SMC_PULSE_XLATE("atmel,smc-ncs-wr-pulse-ns",
                              ATMEL_SMC_NCS_WR_SHIFT),
        ATMEL_SMC_PULSE_XLATE("atmel,smc-nrd-pulse-ns", ATMEL_SMC_NRD_SHIFT),
        ATMEL_SMC_PULSE_XLATE("atmel,smc-nwe-pulse-ns", ATMEL_SMC_NWE_SHIFT),
        ATMEL_SMC_CYCLE_XLATE("atmel,smc-nrd-cycle-ns", ATMEL_SMC_NRD_SHIFT),
        ATMEL_SMC_CYCLE_XLATE("atmel,smc-nwe-cycle-ns", ATMEL_SMC_NWE_SHIFT),
};

static int atmel_ebi_xslate_smc_timings(struct atmel_ebi_dev *ebid,
                                        struct device_node *np,
                                        struct atmel_smc_cs_conf *smcconf)
{
        unsigned int clk_rate = clk_get_rate(ebid->ebi->clk);
        unsigned int clk_period_ns = NSEC_PER_SEC / clk_rate;
        bool required = false;
        unsigned int ncycles;
        int ret, i;
        u32 val;

        ret = of_property_read_u32(np, "atmel,smc-tdf-ns", &val);
        if (!ret) {
                required = true;
                ncycles = DIV_ROUND_UP(val, clk_period_ns);
                if (ncycles > ATMEL_SMC_MODE_TDF_MAX) {
                        ret = -EINVAL;
                        goto out;
                }

                if (ncycles < ATMEL_SMC_MODE_TDF_MIN)
                        ncycles = ATMEL_SMC_MODE_TDF_MIN;

                smcconf->mode |= ATMEL_SMC_MODE_TDF(ncycles);
        }

        for (i = 0; i < ARRAY_SIZE(timings_xlate_table); i++) {
                const struct atmel_smc_timing_xlate *xlate;

                xlate = &timings_xlate_table[i];

                ret = of_property_read_u32(np, xlate->name, &val);
                if (ret) {
                        if (!required)
                                continue;
                        else
                                break;
                }

                if (!required) {
                        ret = -EINVAL;
                        break;
                }

                ncycles = DIV_ROUND_UP(val, clk_period_ns);
                ret = xlate->converter(smcconf, xlate->shift, ncycles);
                if (ret)
                        goto out;
        }

out:
        if (ret) {
                dev_err(ebid->ebi->dev,
                        "missing or invalid timings definition in %pOF",
                        np);
                return ret;
        }

        return required;
}

static int atmel_ebi_xslate_smc_config(struct atmel_ebi_dev *ebid,
                                       struct device_node *np,
                                       struct atmel_ebi_dev_config *conf)
{
        struct atmel_smc_cs_conf *smcconf = &conf->smcconf;
        bool required = false;
        const char *tmp_str;
        u32 tmp;
        int ret;

        ret = of_property_read_u32(np, "atmel,smc-bus-width", &tmp);
        if (!ret) {
                switch (tmp) {
                case 8:
                        smcconf->mode |= ATMEL_SMC_MODE_DBW_8;
                        break;

                case 16:
                        smcconf->mode |= ATMEL_SMC_MODE_DBW_16;
                        break;

                case 32:
                        smcconf->mode |= ATMEL_SMC_MODE_DBW_32;
                        break;

                default:
                        return -EINVAL;
                }

                required = true;
        }

        if (of_property_read_bool(np, "atmel,smc-tdf-optimized")) {
                smcconf->mode |= ATMEL_SMC_MODE_TDFMODE_OPTIMIZED;
                required = true;
        }

        tmp_str = NULL;
        of_property_read_string(np, "atmel,smc-byte-access-type", &tmp_str);
        if (tmp_str && !strcmp(tmp_str, "write")) {
                smcconf->mode |= ATMEL_SMC_MODE_BAT_WRITE;
                required = true;
        }

        tmp_str = NULL;
        of_property_read_string(np, "atmel,smc-read-mode", &tmp_str);
        if (tmp_str && !strcmp(tmp_str, "nrd")) {
                smcconf->mode |= ATMEL_SMC_MODE_READMODE_NRD;
                required = true;
        }

        tmp_str = NULL;
        of_property_read_string(np, "atmel,smc-write-mode", &tmp_str);
        if (tmp_str && !strcmp(tmp_str, "nwe")) {
                smcconf->mode |= ATMEL_SMC_MODE_WRITEMODE_NWE;
                required = true;
        }

        tmp_str = NULL;
        of_property_read_string(np, "atmel,smc-exnw-mode", &tmp_str);
        if (tmp_str) {
                if (!strcmp(tmp_str, "frozen"))
                        smcconf->mode |= ATMEL_SMC_MODE_EXNWMODE_FROZEN;
                else if (!strcmp(tmp_str, "ready"))
                        smcconf->mode |= ATMEL_SMC_MODE_EXNWMODE_READY;
                else if (strcmp(tmp_str, "disabled"))
                        return -EINVAL;

                required = true;
        }

        ret = of_property_read_u32(np, "atmel,smc-page-mode", &tmp);
        if (!ret) {
                switch (tmp) {
                case 4:
                        smcconf->mode |= ATMEL_SMC_MODE_PS_4;
                        break;

                case 8:
                        smcconf->mode |= ATMEL_SMC_MODE_PS_8;
                        break;

                case 16:
                        smcconf->mode |= ATMEL_SMC_MODE_PS_16;
                        break;

                case 32:
                        smcconf->mode |= ATMEL_SMC_MODE_PS_32;
                        break;

                default:
                        return -EINVAL;
                }

                smcconf->mode |= ATMEL_SMC_MODE_PMEN;
                required = true;
        }

        ret = atmel_ebi_xslate_smc_timings(ebid, np, &conf->smcconf);
        if (ret < 0)
                return -EINVAL;

        if ((ret > 0 && !required) || (!ret && required)) {
                dev_err(ebid->ebi->dev, "missing atmel,smc- properties in %pOF",
                        np);
                return -EINVAL;
        }

        return required;
}

static void at91sam9_ebi_apply_config(struct atmel_ebi_dev *ebid,
                                      struct atmel_ebi_dev_config *conf)
{
        atmel_smc_cs_conf_apply(ebid->ebi->smc.regmap, conf->cs,
                                &conf->smcconf);
}

static void sama5_ebi_apply_config(struct atmel_ebi_dev *ebid,
                                   struct atmel_ebi_dev_config *conf)
{
        atmel_hsmc_cs_conf_apply(ebid->ebi->smc.regmap, ebid->ebi->smc.layout,
                                 conf->cs, &conf->smcconf);
}

static int atmel_ebi_dev_setup(struct atmel_ebi *ebi, struct device_node *np,
                               int reg_cells)
{
        const struct atmel_ebi_caps *caps = ebi->caps;
        struct atmel_ebi_dev_config conf = { };
        struct device *dev = ebi->dev;
        struct atmel_ebi_dev *ebid;
        unsigned long cslines = 0;
        int ret, numcs = 0, nentries, i;
        bool apply = false;
        u32 cs;

        nentries = of_property_count_elems_of_size(np, "reg",
                                                   reg_cells * sizeof(u32));
        for (i = 0; i < nentries; i++) {
                ret = of_property_read_u32_index(np, "reg", i * reg_cells,
                                                 &cs);
                if (ret)
                        return ret;

                if (cs >= AT91_EBI_NUM_CS ||
                    !(ebi->caps->available_cs & BIT(cs))) {
                        dev_err(dev, "invalid reg property in %pOF\n", np);
                        return -EINVAL;
                }

                if (!test_and_set_bit(cs, &cslines))
                        numcs++;
        }

        if (!numcs) {
                dev_err(dev, "invalid reg property in %pOF\n", np);
                return -EINVAL;
        }

        ebid = devm_kzalloc(ebi->dev, struct_size(ebid, configs, numcs),
                            GFP_KERNEL);
        if (!ebid)
                return -ENOMEM;

        ebid->ebi = ebi;
        ebid->numcs = numcs;

        ret = caps->xlate_config(ebid, np, &conf);
        if (ret < 0)
                return ret;
        else if (ret)
                apply = true;

        i = 0;
        for_each_set_bit(cs, &cslines, AT91_EBI_NUM_CS) {
                ebid->configs[i].cs = cs;

                if (apply) {
                        conf.cs = cs;
                        caps->apply_config(ebid, &conf);
                }

                caps->get_config(ebid, &ebid->configs[i]);

                /*
                 * Attach the EBI device to the generic SMC logic if at least
                 * one "atmel,smc-" property is present.
                 */
                if (ebi->caps->ebi_csa_offs && apply)
                        regmap_update_bits(ebi->regmap,
                                           ebi->caps->ebi_csa_offs,
                                           BIT(cs), 0);

                i++;
        }

        list_add_tail(&ebid->node, &ebi->devs);

        return 0;
}

static const struct atmel_ebi_caps at91sam9260_ebi_caps = {
        .available_cs = 0xff,
        .ebi_csa_offs = AT91SAM9260_MATRIX_EBICSA,
        .regmap_name = "atmel,matrix",
        .get_config = at91sam9_ebi_get_config,
        .xlate_config = atmel_ebi_xslate_smc_config,
        .apply_config = at91sam9_ebi_apply_config,
};

static const struct atmel_ebi_caps at91sam9261_ebi_caps = {
        .available_cs = 0xff,
        .ebi_csa_offs = AT91SAM9261_MATRIX_EBICSA,
        .regmap_name = "atmel,matrix",
        .get_config = at91sam9_ebi_get_config,
        .xlate_config = atmel_ebi_xslate_smc_config,
        .apply_config = at91sam9_ebi_apply_config,
};

static const struct atmel_ebi_caps at91sam9263_ebi0_caps = {
        .available_cs = 0x3f,
        .ebi_csa_offs = AT91SAM9263_MATRIX_EBI0CSA,
        .regmap_name = "atmel,matrix",
        .get_config = at91sam9_ebi_get_config,
        .xlate_config = atmel_ebi_xslate_smc_config,
        .apply_config = at91sam9_ebi_apply_config,
};

static const struct atmel_ebi_caps at91sam9263_ebi1_caps = {
        .available_cs = 0x7,
        .ebi_csa_offs = AT91SAM9263_MATRIX_EBI1CSA,
        .regmap_name = "atmel,matrix",
        .get_config = at91sam9_ebi_get_config,
        .xlate_config = atmel_ebi_xslate_smc_config,
        .apply_config = at91sam9_ebi_apply_config,
};

static const struct atmel_ebi_caps at91sam9rl_ebi_caps = {
        .available_cs = 0x3f,
        .ebi_csa_offs = AT91SAM9RL_MATRIX_EBICSA,
        .regmap_name = "atmel,matrix",
        .get_config = at91sam9_ebi_get_config,
        .xlate_config = atmel_ebi_xslate_smc_config,
        .apply_config = at91sam9_ebi_apply_config,
};

static const struct atmel_ebi_caps at91sam9g45_ebi_caps = {
        .available_cs = 0x3f,
        .ebi_csa_offs = AT91SAM9G45_MATRIX_EBICSA,
        .regmap_name = "atmel,matrix",
        .get_config = at91sam9_ebi_get_config,
        .xlate_config = atmel_ebi_xslate_smc_config,
        .apply_config = at91sam9_ebi_apply_config,
};

static const struct atmel_ebi_caps at91sam9x5_ebi_caps = {
        .available_cs = 0x3f,
        .ebi_csa_offs = AT91SAM9X5_MATRIX_EBICSA,
        .regmap_name = "atmel,matrix",
        .get_config = at91sam9_ebi_get_config,
        .xlate_config = atmel_ebi_xslate_smc_config,
        .apply_config = at91sam9_ebi_apply_config,
};

static const struct atmel_ebi_caps sama5d3_ebi_caps = {
        .available_cs = 0xf,
        .get_config = sama5_ebi_get_config,
        .xlate_config = atmel_ebi_xslate_smc_config,
        .apply_config = sama5_ebi_apply_config,
};

static const struct atmel_ebi_caps sam9x60_ebi_caps = {
        .available_cs = 0x3f,
        .ebi_csa_offs = AT91_SFR_CCFG_EBICSA,
        .regmap_name = "microchip,sfr",
        .get_config = at91sam9_ebi_get_config,
        .xlate_config = atmel_ebi_xslate_smc_config,
        .apply_config = at91sam9_ebi_apply_config,
};

static const struct of_device_id atmel_ebi_id_table[] = {
        {
                .compatible = "atmel,at91sam9260-ebi",
                .data = &at91sam9260_ebi_caps,
        },
        {
                .compatible = "atmel,at91sam9261-ebi",
                .data = &at91sam9261_ebi_caps,
        },
        {
                .compatible = "atmel,at91sam9263-ebi0",
                .data = &at91sam9263_ebi0_caps,
        },
        {
                .compatible = "atmel,at91sam9263-ebi1",
                .data = &at91sam9263_ebi1_caps,
        },
        {
                .compatible = "atmel,at91sam9rl-ebi",
                .data = &at91sam9rl_ebi_caps,
        },
        {
                .compatible = "atmel,at91sam9g45-ebi",
                .data = &at91sam9g45_ebi_caps,
        },
        {
                .compatible = "atmel,at91sam9x5-ebi",
                .data = &at91sam9x5_ebi_caps,
        },
        {
                .compatible = "atmel,sama5d3-ebi",
                .data = &sama5d3_ebi_caps,
        },
        {
                .compatible = "microchip,sam9x60-ebi",
                .data = &sam9x60_ebi_caps,
        },
        { /* sentinel */ }
};

static int atmel_ebi_dev_disable(struct atmel_ebi *ebi, struct device_node *np)
{
        struct device *dev = ebi->dev;
        struct property *newprop;

        newprop = devm_kzalloc(dev, sizeof(*newprop), GFP_KERNEL);
        if (!newprop)
                return -ENOMEM;

        newprop->name = devm_kstrdup(dev, "status", GFP_KERNEL);
        if (!newprop->name)
                return -ENOMEM;

        newprop->value = devm_kstrdup(dev, "disabled", GFP_KERNEL);
        if (!newprop->value)
                return -ENOMEM;

        newprop->length = sizeof("disabled");

        return of_update_property(np, newprop);
}

static int atmel_ebi_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct device_node *np = dev->of_node;
        struct atmel_ebi *ebi;
        int ret, reg_cells;
        struct clk *clk;
        u32 val;

        ebi = devm_kzalloc(dev, sizeof(*ebi), GFP_KERNEL);
        if (!ebi)
                return -ENOMEM;

        platform_set_drvdata(pdev, ebi);

        INIT_LIST_HEAD(&ebi->devs);
        ebi->caps = device_get_match_data(dev);
        if (!ebi->caps)
                return -EINVAL;
        ebi->dev = dev;

        clk = devm_clk_get(dev, NULL);
        if (IS_ERR(clk))
                return PTR_ERR(clk);

        ebi->clk = clk;

        struct device_node *smc_np __free(device_node) =
                of_parse_phandle(dev->of_node, "atmel,smc", 0);

        ebi->smc.regmap = syscon_node_to_regmap(smc_np);
        if (IS_ERR(ebi->smc.regmap))
                return PTR_ERR(ebi->smc.regmap);

        ebi->smc.layout = atmel_hsmc_get_reg_layout(smc_np);
        if (IS_ERR(ebi->smc.layout))
                return PTR_ERR(ebi->smc.layout);

        ebi->smc.clk = of_clk_get(smc_np, 0);
        if (IS_ERR(ebi->smc.clk)) {
                if (PTR_ERR(ebi->smc.clk) != -ENOENT)
                        return PTR_ERR(ebi->smc.clk);

                ebi->smc.clk = NULL;
        }
        ret = clk_prepare_enable(ebi->smc.clk);
        if (ret)
                return ret;

        /*
         * The sama5d3 does not provide an EBICSA register and thus does need
         * to access it.
         */
        if (ebi->caps->ebi_csa_offs) {
                ebi->regmap =
                        syscon_regmap_lookup_by_phandle(np,
                                                        ebi->caps->regmap_name);
                if (IS_ERR(ebi->regmap))
                        return PTR_ERR(ebi->regmap);
        }

        ret = of_property_read_u32(np, "#address-cells", &val);
        if (ret) {
                dev_err(dev, "missing #address-cells property\n");
                return ret;
        }

        reg_cells = val;

        ret = of_property_read_u32(np, "#size-cells", &val);
        if (ret) {
                dev_err(dev, "missing #address-cells property\n");
                return ret;
        }

        reg_cells += val;

        for_each_available_child_of_node_scoped(np, child) {
                if (!of_property_present(child, "reg"))
                        continue;

                ret = atmel_ebi_dev_setup(ebi, child, reg_cells);
                if (ret) {
                        dev_err(dev, "failed to configure EBI bus for %pOF, disabling the device",
                                child);

                        ret = atmel_ebi_dev_disable(ebi, child);
                        if (ret)
                                return ret;
                }
        }

        return of_platform_populate(np, NULL, NULL, dev);
}

static __maybe_unused int atmel_ebi_resume(struct device *dev)
{
        struct atmel_ebi *ebi = dev_get_drvdata(dev);
        struct atmel_ebi_dev *ebid;

        list_for_each_entry(ebid, &ebi->devs, node) {
                int i;

                for (i = 0; i < ebid->numcs; i++)
                        ebid->ebi->caps->apply_config(ebid, &ebid->configs[i]);
        }

        return 0;
}

static SIMPLE_DEV_PM_OPS(atmel_ebi_pm_ops, NULL, atmel_ebi_resume);

static struct platform_driver atmel_ebi_driver = {
        .driver = {
                .name = "atmel-ebi",
                .of_match_table = atmel_ebi_id_table,
                .pm = &atmel_ebi_pm_ops,
        },
};
builtin_platform_driver_probe(atmel_ebi_driver, atmel_ebi_probe);