/*
 * EIM driver for Freescale's i.MX chips
 *
 * Copyright (C) 2013 Freescale Semiconductor, Inc.
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */
#include <linux/module.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/mfd/syscon.h>
#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
#include <linux/regmap.h>

struct imx_weim_devtype {
        unsigned int    cs_count;
        unsigned int    cs_regs_count;
        unsigned int    cs_stride;
        unsigned int    wcr_offset;
        unsigned int    wcr_bcm;
        unsigned int    wcr_cont_bclk;
};

static const struct imx_weim_devtype imx1_weim_devtype = {
        .cs_count       = 6,
        .cs_regs_count  = 2,
        .cs_stride      = 0x08,
};

static const struct imx_weim_devtype imx27_weim_devtype = {
        .cs_count       = 6,
        .cs_regs_count  = 3,
        .cs_stride      = 0x10,
};

static const struct imx_weim_devtype imx50_weim_devtype = {
        .cs_count       = 4,
        .cs_regs_count  = 6,
        .cs_stride      = 0x18,
        .wcr_offset     = 0x90,
        .wcr_bcm        = BIT(0),
        .wcr_cont_bclk  = BIT(3),
};

static const struct imx_weim_devtype imx51_weim_devtype = {
        .cs_count       = 6,
        .cs_regs_count  = 6,
        .cs_stride      = 0x18,
};

#define MAX_CS_REGS_COUNT       6
#define MAX_CS_COUNT            6
#define OF_REG_SIZE             3

struct cs_timing {
        bool is_applied;
        u32 regs[MAX_CS_REGS_COUNT];
};

struct cs_timing_state {
        struct cs_timing cs[MAX_CS_COUNT];
};

struct weim_priv {
        void __iomem *base;
        struct cs_timing_state timing_state;
};

static const struct of_device_id weim_id_table[] = {
        /* i.MX1/21 */
        { .compatible = "fsl,imx1-weim", .data = &imx1_weim_devtype, },
        /* i.MX25/27/31/35 */
        { .compatible = "fsl,imx27-weim", .data = &imx27_weim_devtype, },
        /* i.MX50/53/6Q */
        { .compatible = "fsl,imx50-weim", .data = &imx50_weim_devtype, },
        { .compatible = "fsl,imx6q-weim", .data = &imx50_weim_devtype, },
        /* i.MX51 */
        { .compatible = "fsl,imx51-weim", .data = &imx51_weim_devtype, },
        { }
};
MODULE_DEVICE_TABLE(of, weim_id_table);

static int imx_weim_gpr_setup(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        struct of_range_parser parser;
        struct of_range range;
        struct regmap *gpr;
        u32 gprvals[4] = {
                05,     /* CS0(128M) CS1(0M)  CS2(0M)  CS3(0M)  */
                033,    /* CS0(64M)  CS1(64M) CS2(0M)  CS3(0M)  */
                0113,   /* CS0(64M)  CS1(32M) CS2(32M) CS3(0M)  */
                01111,  /* CS0(32M)  CS1(32M) CS2(32M) CS3(32M) */
        };
        u32 gprval = 0;
        u32 val;
        int cs = 0;
        int i = 0;

        gpr = syscon_regmap_lookup_by_phandle(np, "fsl,weim-cs-gpr");
        if (IS_ERR(gpr)) {
                dev_dbg(&pdev->dev, "failed to find weim-cs-gpr\n");
                return 0;
        }

        if (of_range_parser_init(&parser, np))
                goto err;

        for_each_of_range(&parser, &range) {
                cs = range.bus_addr >> 32;
                val = (range.size / SZ_32M) | 1;
                gprval |= val << cs * 3;
                i++;
        }

        if (i == 0)
                goto err;

        for (i = 0; i < ARRAY_SIZE(gprvals); i++) {
                if (gprval == gprvals[i]) {
                        /* Found it. Set up IOMUXC_GPR1[11:0] with it. */
                        regmap_update_bits(gpr, IOMUXC_GPR1, 0xfff, gprval);
                        return 0;
                }
        }

err:
        dev_err(&pdev->dev, "Invalid 'ranges' configuration\n");
        return -EINVAL;
}

/* Parse and set the timing for this device. */
static int weim_timing_setup(struct device *dev, struct device_node *np,
                             const struct imx_weim_devtype *devtype)
{
        u32 cs_idx, value[MAX_CS_REGS_COUNT];
        int i, ret;
        int reg_idx, num_regs;
        struct cs_timing *cst;
        struct weim_priv *priv;
        struct cs_timing_state *ts;
        void __iomem *base;

        if (WARN_ON(devtype->cs_regs_count > MAX_CS_REGS_COUNT))
                return -EINVAL;
        if (WARN_ON(devtype->cs_count > MAX_CS_COUNT))
                return -EINVAL;

        priv = dev_get_drvdata(dev);
        base = priv->base;
        ts = &priv->timing_state;

        ret = of_property_read_u32_array(np, "fsl,weim-cs-timing",
                                         value, devtype->cs_regs_count);
        if (ret)
                return ret;

        /*
         * the child node's "reg" property may contain multiple address ranges,
         * extract the chip select for each.
         */
        num_regs = of_property_count_elems_of_size(np, "reg", OF_REG_SIZE);
        if (num_regs < 0)
                return num_regs;
        if (!num_regs)
                return -EINVAL;
        for (reg_idx = 0; reg_idx < num_regs; reg_idx++) {
                /* get the CS index from this child node's "reg" property. */
                ret = of_property_read_u32_index(np, "reg",
                                        reg_idx * OF_REG_SIZE, &cs_idx);
                if (ret)
                        break;

                if (cs_idx >= devtype->cs_count)
                        return -EINVAL;

                /* prevent re-configuring a CS that's already been configured */
                cst = &ts->cs[cs_idx];
                if (cst->is_applied && memcmp(value, cst->regs,
                                        devtype->cs_regs_count * sizeof(u32))) {
                        dev_err(dev, "fsl,weim-cs-timing conflict on %pOF", np);
                        return -EINVAL;
                }

                /* set the timing for WEIM */
                for (i = 0; i < devtype->cs_regs_count; i++)
                        writel(value[i],
                                base + cs_idx * devtype->cs_stride + i * 4);
                if (!cst->is_applied) {
                        cst->is_applied = true;
                        memcpy(cst->regs, value,
                                devtype->cs_regs_count * sizeof(u32));
                }
        }

        return 0;
}

static int weim_parse_dt(struct platform_device *pdev)
{
        const struct imx_weim_devtype *devtype = device_get_match_data(&pdev->dev);
        int ret = 0, have_child = 0;
        struct device_node *child;
        struct weim_priv *priv;
        void __iomem *base;
        u32 reg;

        if (devtype == &imx50_weim_devtype) {
                ret = imx_weim_gpr_setup(pdev);
                if (ret)
                        return ret;
        }

        priv = dev_get_drvdata(&pdev->dev);
        base = priv->base;

        if (of_property_read_bool(pdev->dev.of_node, "fsl,burst-clk-enable")) {
                if (devtype->wcr_bcm) {
                        reg = readl(base + devtype->wcr_offset);
                        reg |= devtype->wcr_bcm;

                        if (of_property_read_bool(pdev->dev.of_node,
                                                "fsl,continuous-burst-clk")) {
                                if (devtype->wcr_cont_bclk) {
                                        reg |= devtype->wcr_cont_bclk;
                                } else {
                                        dev_err(&pdev->dev,
                                                "continuous burst clk not supported.\n");
                                        return -EINVAL;
                                }
                        }

                        writel(reg, base + devtype->wcr_offset);
                } else {
                        dev_err(&pdev->dev, "burst clk mode not supported.\n");
                        return -EINVAL;
                }
        }

        for_each_available_child_of_node(pdev->dev.of_node, child) {
                ret = weim_timing_setup(&pdev->dev, child, devtype);
                if (ret)
                        dev_warn(&pdev->dev, "%pOF set timing failed.\n",
                                child);
                else
                        have_child = 1;
        }

        if (have_child)
                ret = of_platform_default_populate(pdev->dev.of_node,
                                                   NULL, &pdev->dev);
        if (ret)
                dev_err(&pdev->dev, "%pOF fail to create devices.\n",
                        pdev->dev.of_node);
        return ret;
}

static int weim_probe(struct platform_device *pdev)
{
        struct weim_priv *priv;
        struct clk *clk;
        void __iomem *base;
        int ret;

        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        /* get the resource */
        base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(base))
                return PTR_ERR(base);

        priv->base = base;
        dev_set_drvdata(&pdev->dev, priv);

        /* get the clock */
        clk = devm_clk_get_enabled(&pdev->dev, NULL);
        if (IS_ERR(clk))
                return PTR_ERR(clk);

        /* parse the device node */
        ret = weim_parse_dt(pdev);
        if (ret)
                return ret;

        dev_info(&pdev->dev, "Driver registered.\n");

        return 0;
}

#if IS_ENABLED(CONFIG_OF_DYNAMIC)
static int of_weim_notify(struct notifier_block *nb, unsigned long action,
                          void *arg)
{
        const struct imx_weim_devtype *devtype;
        struct of_reconfig_data *rd = arg;
        const struct of_device_id *of_id;
        struct platform_device *pdev;
        int ret = NOTIFY_OK;

        switch (of_reconfig_get_state_change(action, rd)) {
        case OF_RECONFIG_CHANGE_ADD:
                of_id = of_match_node(weim_id_table, rd->dn->parent);
                if (!of_id)
                        return NOTIFY_OK; /* not for us */

                devtype = of_id->data;

                pdev = of_find_device_by_node(rd->dn->parent);
                if (!pdev) {
                        pr_err("%s: could not find platform device for '%pOF'\n",
                                __func__, rd->dn->parent);

                        return notifier_from_errno(-EINVAL);
                }

                if (weim_timing_setup(&pdev->dev, rd->dn, devtype))
                        dev_warn(&pdev->dev,
                                 "Failed to setup timing for '%pOF'\n", rd->dn);

                if (!of_node_check_flag(rd->dn, OF_POPULATED)) {
                        /*
                         * Clear the flag before adding the device so that
                         * fw_devlink doesn't skip adding consumers to this
                         * device.
                         */
                        rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE;
                        if (!of_platform_device_create(rd->dn, NULL, &pdev->dev)) {
                                dev_err(&pdev->dev,
                                        "Failed to create child device '%pOF'\n",
                                        rd->dn);
                                ret = notifier_from_errno(-EINVAL);
                        }
                }

                platform_device_put(pdev);

                break;
        case OF_RECONFIG_CHANGE_REMOVE:
                if (!of_node_check_flag(rd->dn, OF_POPULATED))
                        return NOTIFY_OK; /* device already destroyed */

                of_id = of_match_node(weim_id_table, rd->dn->parent);
                if (!of_id)
                        return NOTIFY_OK; /* not for us */

                pdev = of_find_device_by_node(rd->dn);
                if (!pdev) {
                        pr_err("Could not find platform device for '%pOF'\n",
                                rd->dn);

                        ret = notifier_from_errno(-EINVAL);
                } else {
                        of_platform_device_destroy(&pdev->dev, NULL);
                        platform_device_put(pdev);
                }

                break;
        default:
                break;
        }

        return ret;
}

static struct notifier_block weim_of_notifier = {
        .notifier_call = of_weim_notify,
};
#endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */

static struct platform_driver weim_driver = {
        .driver = {
                .name           = "imx-weim",
                .of_match_table = weim_id_table,
        },
        .probe = weim_probe,
};

static int __init weim_init(void)
{
#if IS_ENABLED(CONFIG_OF_DYNAMIC)
        WARN_ON(of_reconfig_notifier_register(&weim_of_notifier));
#endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */

        return platform_driver_register(&weim_driver);
}
module_init(weim_init);

static void __exit weim_exit(void)
{
#if IS_ENABLED(CONFIG_OF_DYNAMIC)
        of_reconfig_notifier_unregister(&weim_of_notifier);
#endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */

        return platform_driver_unregister(&weim_driver);

}
module_exit(weim_exit);

MODULE_AUTHOR("Freescale Semiconductor Inc.");
MODULE_DESCRIPTION("i.MX EIM Controller Driver");
MODULE_LICENSE("GPL");