/*
 * Intel Sunrisepoint LPSS core support.
 *
 * Copyright (C) 2015, Intel Corporation
 *
 * Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
 *          Mika Westerberg <mika.westerberg@linux.intel.com>
 *          Heikki Krogerus <heikki.krogerus@linux.intel.com>
 *          Jarkko Nikula <jarkko.nikula@linux.intel.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/clk-provider.h>
#include <linux/debugfs.h>
#include <linux/idr.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mfd/core.h>
#include <linux/pm_qos.h>
#include <linux/pm_runtime.h>
#include <linux/property.h>
#include <linux/seq_file.h>
#include <linux/io-64-nonatomic-lo-hi.h>

#include "intel-lpss.h"

#define LPSS_DEV_OFFSET         0x000
#define LPSS_DEV_SIZE           0x200
#define LPSS_PRIV_OFFSET        0x200
#define LPSS_PRIV_SIZE          0x100
#define LPSS_IDMA64_OFFSET      0x800
#define LPSS_IDMA64_SIZE        0x800

/* Offsets from lpss->priv */
#define LPSS_PRIV_RESETS                0x04
#define LPSS_PRIV_RESETS_FUNC           BIT(2)
#define LPSS_PRIV_RESETS_IDMA           0x3

#define LPSS_PRIV_ACTIVELTR             0x10
#define LPSS_PRIV_IDLELTR               0x14

#define LPSS_PRIV_LTR_REQ               BIT(15)
#define LPSS_PRIV_LTR_SCALE_MASK        0xc00
#define LPSS_PRIV_LTR_SCALE_1US         0x800
#define LPSS_PRIV_LTR_SCALE_32US        0xc00
#define LPSS_PRIV_LTR_VALUE_MASK        0x3ff

#define LPSS_PRIV_SSP_REG               0x20
#define LPSS_PRIV_SSP_REG_DIS_DMA_FIN   BIT(0)

#define LPSS_PRIV_REMAP_ADDR            0x40

#define LPSS_PRIV_CAPS                  0xfc
#define LPSS_PRIV_CAPS_NO_IDMA          BIT(8)
#define LPSS_PRIV_CAPS_TYPE_SHIFT       4
#define LPSS_PRIV_CAPS_TYPE_MASK        (0xf << LPSS_PRIV_CAPS_TYPE_SHIFT)

/* This matches the type field in CAPS register */
enum intel_lpss_dev_type {
        LPSS_DEV_I2C = 0,
        LPSS_DEV_UART,
        LPSS_DEV_SPI,
};

struct intel_lpss {
        const struct intel_lpss_platform_info *info;
        enum intel_lpss_dev_type type;
        struct clk *clk;
        struct clk_lookup *clock;
        struct mfd_cell *cell;
        struct device *dev;
        void __iomem *priv;
        int devid;
        u32 caps;
        u32 active_ltr;
        u32 idle_ltr;
        struct dentry *debugfs;
};

static const struct resource intel_lpss_dev_resources[] = {
        DEFINE_RES_MEM_NAMED(LPSS_DEV_OFFSET, LPSS_DEV_SIZE, "lpss_dev"),
        DEFINE_RES_MEM_NAMED(LPSS_PRIV_OFFSET, LPSS_PRIV_SIZE, "lpss_priv"),
        DEFINE_RES_IRQ(0),
};

static const struct resource intel_lpss_idma64_resources[] = {
        DEFINE_RES_MEM(LPSS_IDMA64_OFFSET, LPSS_IDMA64_SIZE),
        DEFINE_RES_IRQ(0),
};

#define LPSS_IDMA64_DRIVER_NAME         "idma64"

/*
 * Cells needs to be ordered so that the iDMA is created first. This is
 * because we need to be sure the DMA is available when the host controller
 * driver is probed.
 */
static const struct mfd_cell intel_lpss_idma64_cell = {
        .name = LPSS_IDMA64_DRIVER_NAME,
        .num_resources = ARRAY_SIZE(intel_lpss_idma64_resources),
        .resources = intel_lpss_idma64_resources,
};

static const struct mfd_cell intel_lpss_i2c_cell = {
        .name = "i2c_designware",
        .num_resources = ARRAY_SIZE(intel_lpss_dev_resources),
        .resources = intel_lpss_dev_resources,
};

static const struct mfd_cell intel_lpss_uart_cell = {
        .name = "dw-apb-uart",
        .num_resources = ARRAY_SIZE(intel_lpss_dev_resources),
        .resources = intel_lpss_dev_resources,
};

static const struct mfd_cell intel_lpss_spi_cell = {
        .name = "pxa2xx-spi",
        .num_resources = ARRAY_SIZE(intel_lpss_dev_resources),
        .resources = intel_lpss_dev_resources,
};

static DEFINE_IDA(intel_lpss_devid_ida);
static struct dentry *intel_lpss_debugfs;

static int intel_lpss_request_dma_module(const char *name)
{
        static bool intel_lpss_dma_requested;

        if (intel_lpss_dma_requested)
                return 0;

        intel_lpss_dma_requested = true;
        return request_module("%s", name);
}

static void intel_lpss_cache_ltr(struct intel_lpss *lpss)
{
        lpss->active_ltr = readl(lpss->priv + LPSS_PRIV_ACTIVELTR);
        lpss->idle_ltr = readl(lpss->priv + LPSS_PRIV_IDLELTR);
}

static int intel_lpss_debugfs_add(struct intel_lpss *lpss)
{
        struct dentry *dir;

        dir = debugfs_create_dir(dev_name(lpss->dev), intel_lpss_debugfs);
        if (IS_ERR(dir))
                return PTR_ERR(dir);

        /* Cache the values into lpss structure */
        intel_lpss_cache_ltr(lpss);

        debugfs_create_x32("capabilities", S_IRUGO, dir, &lpss->caps);
        debugfs_create_x32("active_ltr", S_IRUGO, dir, &lpss->active_ltr);
        debugfs_create_x32("idle_ltr", S_IRUGO, dir, &lpss->idle_ltr);

        lpss->debugfs = dir;
        return 0;
}

static void intel_lpss_debugfs_remove(struct intel_lpss *lpss)
{
        debugfs_remove_recursive(lpss->debugfs);
}

static void intel_lpss_ltr_set(struct device *dev, s32 val)
{
        struct intel_lpss *lpss = dev_get_drvdata(dev);
        u32 ltr;

        /*
         * Program latency tolerance (LTR) accordingly what has been asked
         * by the PM QoS layer or disable it in case we were passed
         * negative value or PM_QOS_LATENCY_ANY.
         */
        ltr = readl(lpss->priv + LPSS_PRIV_ACTIVELTR);

        if (val == PM_QOS_LATENCY_ANY || val < 0) {
                ltr &= ~LPSS_PRIV_LTR_REQ;
        } else {
                ltr |= LPSS_PRIV_LTR_REQ;
                ltr &= ~LPSS_PRIV_LTR_SCALE_MASK;
                ltr &= ~LPSS_PRIV_LTR_VALUE_MASK;

                if (val > LPSS_PRIV_LTR_VALUE_MASK)
                        ltr |= LPSS_PRIV_LTR_SCALE_32US | val >> 5;
                else
                        ltr |= LPSS_PRIV_LTR_SCALE_1US | val;
        }

        if (ltr == lpss->active_ltr)
                return;

        writel(ltr, lpss->priv + LPSS_PRIV_ACTIVELTR);
        writel(ltr, lpss->priv + LPSS_PRIV_IDLELTR);

        /* Cache the values into lpss structure */
        intel_lpss_cache_ltr(lpss);
}

static void intel_lpss_ltr_expose(struct intel_lpss *lpss)
{
        lpss->dev->power.set_latency_tolerance = intel_lpss_ltr_set;
        dev_pm_qos_expose_latency_tolerance(lpss->dev);
}

static void intel_lpss_ltr_hide(struct intel_lpss *lpss)
{
        dev_pm_qos_hide_latency_tolerance(lpss->dev);
        lpss->dev->power.set_latency_tolerance = NULL;
}

static int intel_lpss_assign_devs(struct intel_lpss *lpss)
{
        const struct mfd_cell *cell;
        unsigned int type;

        type = lpss->caps & LPSS_PRIV_CAPS_TYPE_MASK;
        type >>= LPSS_PRIV_CAPS_TYPE_SHIFT;

        switch (type) {
        case LPSS_DEV_I2C:
                cell = &intel_lpss_i2c_cell;
                break;
        case LPSS_DEV_UART:
                cell = &intel_lpss_uart_cell;
                break;
        case LPSS_DEV_SPI:
                cell = &intel_lpss_spi_cell;
                break;
        default:
                return -ENODEV;
        }

        lpss->cell = devm_kmemdup(lpss->dev, cell, sizeof(*cell), GFP_KERNEL);
        if (!lpss->cell)
                return -ENOMEM;

        lpss->type = type;

        return 0;
}

static bool intel_lpss_has_idma(const struct intel_lpss *lpss)
{
        return (lpss->caps & LPSS_PRIV_CAPS_NO_IDMA) == 0;
}

static void intel_lpss_set_remap_addr(const struct intel_lpss *lpss)
{
        resource_size_t addr = lpss->info->mem->start;

        lo_hi_writeq(addr, lpss->priv + LPSS_PRIV_REMAP_ADDR);
}

static void intel_lpss_deassert_reset(const struct intel_lpss *lpss)
{
        u32 value = LPSS_PRIV_RESETS_FUNC | LPSS_PRIV_RESETS_IDMA;

        /* Bring out the device from reset */
        writel(value, lpss->priv + LPSS_PRIV_RESETS);
}

static void intel_lpss_init_dev(const struct intel_lpss *lpss)
{
        u32 value = LPSS_PRIV_SSP_REG_DIS_DMA_FIN;

        intel_lpss_deassert_reset(lpss);

        if (!intel_lpss_has_idma(lpss))
                return;

        intel_lpss_set_remap_addr(lpss);

        /* Make sure that SPI multiblock DMA transfers are re-enabled */
        if (lpss->type == LPSS_DEV_SPI)
                writel(value, lpss->priv + LPSS_PRIV_SSP_REG);
}

static void intel_lpss_unregister_clock_tree(struct clk *clk)
{
        struct clk *parent;

        while (clk) {
                parent = clk_get_parent(clk);
                clk_unregister(clk);
                clk = parent;
        }
}

static int intel_lpss_register_clock_divider(struct intel_lpss *lpss,
                                             const char *devname,
                                             struct clk **clk)
{
        char name[32];
        struct clk *tmp = *clk;

        snprintf(name, sizeof(name), "%s-enable", devname);
        tmp = clk_register_gate(NULL, name, __clk_get_name(tmp), 0,
                                lpss->priv, 0, 0, NULL);
        if (IS_ERR(tmp))
                return PTR_ERR(tmp);

        snprintf(name, sizeof(name), "%s-div", devname);
        tmp = clk_register_fractional_divider(NULL, name, __clk_get_name(tmp),
                                              0, lpss->priv, 1, 15, 16, 15, 0,
                                              NULL);
        if (IS_ERR(tmp))
                return PTR_ERR(tmp);
        *clk = tmp;

        snprintf(name, sizeof(name), "%s-update", devname);
        tmp = clk_register_gate(NULL, name, __clk_get_name(tmp),
                                CLK_SET_RATE_PARENT, lpss->priv, 31, 0, NULL);
        if (IS_ERR(tmp))
                return PTR_ERR(tmp);
        *clk = tmp;

        return 0;
}

static int intel_lpss_register_clock(struct intel_lpss *lpss)
{
        const struct mfd_cell *cell = lpss->cell;
        struct clk *clk;
        char devname[24];
        int ret;

        if (!lpss->info->clk_rate)
                return 0;

        /* Root clock */
        clk = clk_register_fixed_rate(NULL, dev_name(lpss->dev), NULL,
                                      CLK_IS_ROOT, lpss->info->clk_rate);
        if (IS_ERR(clk))
                return PTR_ERR(clk);

        snprintf(devname, sizeof(devname), "%s.%d", cell->name, lpss->devid);

        /*
         * Support for clock divider only if it has some preset value.
         * Otherwise we assume that the divider is not used.
         */
        if (lpss->type != LPSS_DEV_I2C) {
                ret = intel_lpss_register_clock_divider(lpss, devname, &clk);
                if (ret)
                        goto err_clk_register;
        }

        ret = -ENOMEM;

        /* Clock for the host controller */
        lpss->clock = clkdev_create(clk, lpss->info->clk_con_id, "%s", devname);
        if (!lpss->clock)
                goto err_clk_register;

        lpss->clk = clk;

        return 0;

err_clk_register:
        intel_lpss_unregister_clock_tree(clk);

        return ret;
}

static void intel_lpss_unregister_clock(struct intel_lpss *lpss)
{
        if (IS_ERR_OR_NULL(lpss->clk))
                return;

        clkdev_drop(lpss->clock);
        intel_lpss_unregister_clock_tree(lpss->clk);
}

int intel_lpss_probe(struct device *dev,
                     const struct intel_lpss_platform_info *info)
{
        struct intel_lpss *lpss;
        int ret;

        if (!info || !info->mem || info->irq <= 0)
                return -EINVAL;

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

        lpss->priv = devm_ioremap(dev, info->mem->start + LPSS_PRIV_OFFSET,
                                  LPSS_PRIV_SIZE);
        if (!lpss->priv)
                return -ENOMEM;

        lpss->info = info;
        lpss->dev = dev;
        lpss->caps = readl(lpss->priv + LPSS_PRIV_CAPS);

        dev_set_drvdata(dev, lpss);

        ret = intel_lpss_assign_devs(lpss);
        if (ret)
                return ret;

        lpss->cell->pset = info->pset;

        intel_lpss_init_dev(lpss);

        lpss->devid = ida_simple_get(&intel_lpss_devid_ida, 0, 0, GFP_KERNEL);
        if (lpss->devid < 0)
                return lpss->devid;

        ret = intel_lpss_register_clock(lpss);
        if (ret)
                goto err_clk_register;

        intel_lpss_ltr_expose(lpss);

        ret = intel_lpss_debugfs_add(lpss);
        if (ret)
                dev_warn(dev, "Failed to create debugfs entries\n");

        if (intel_lpss_has_idma(lpss)) {
                /*
                 * Ensure the DMA driver is loaded before the host
                 * controller device appears, so that the host controller
                 * driver can request its DMA channels as early as
                 * possible.
                 *
                 * If the DMA module is not there that's OK as well.
                 */
                intel_lpss_request_dma_module(LPSS_IDMA64_DRIVER_NAME);

                ret = mfd_add_devices(dev, lpss->devid, &intel_lpss_idma64_cell,
                                      1, info->mem, info->irq, NULL);
                if (ret)
                        dev_warn(dev, "Failed to add %s, fallback to PIO\n",
                                 LPSS_IDMA64_DRIVER_NAME);
        }

        ret = mfd_add_devices(dev, lpss->devid, lpss->cell,
                              1, info->mem, info->irq, NULL);
        if (ret)
                goto err_remove_ltr;

        return 0;

err_remove_ltr:
        intel_lpss_debugfs_remove(lpss);
        intel_lpss_ltr_hide(lpss);

err_clk_register:
        ida_simple_remove(&intel_lpss_devid_ida, lpss->devid);

        return ret;
}
EXPORT_SYMBOL_GPL(intel_lpss_probe);

void intel_lpss_remove(struct device *dev)
{
        struct intel_lpss *lpss = dev_get_drvdata(dev);

        mfd_remove_devices(dev);
        intel_lpss_debugfs_remove(lpss);
        intel_lpss_ltr_hide(lpss);
        intel_lpss_unregister_clock(lpss);
        ida_simple_remove(&intel_lpss_devid_ida, lpss->devid);
}
EXPORT_SYMBOL_GPL(intel_lpss_remove);

static int resume_lpss_device(struct device *dev, void *data)
{
        pm_runtime_resume(dev);
        return 0;
}

int intel_lpss_prepare(struct device *dev)
{
        /*
         * Resume both child devices before entering system sleep. This
         * ensures that they are in proper state before they get suspended.
         */
        device_for_each_child_reverse(dev, NULL, resume_lpss_device);
        return 0;
}
EXPORT_SYMBOL_GPL(intel_lpss_prepare);

int intel_lpss_suspend(struct device *dev)
{
        return 0;
}
EXPORT_SYMBOL_GPL(intel_lpss_suspend);

int intel_lpss_resume(struct device *dev)
{
        struct intel_lpss *lpss = dev_get_drvdata(dev);

        intel_lpss_init_dev(lpss);

        return 0;
}
EXPORT_SYMBOL_GPL(intel_lpss_resume);

static int __init intel_lpss_init(void)
{
        intel_lpss_debugfs = debugfs_create_dir("intel_lpss", NULL);
        return 0;
}
module_init(intel_lpss_init);

static void __exit intel_lpss_exit(void)
{
        debugfs_remove(intel_lpss_debugfs);
}
module_exit(intel_lpss_exit);

MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
MODULE_AUTHOR("Jarkko Nikula <jarkko.nikula@linux.intel.com>");
MODULE_DESCRIPTION("Intel LPSS core driver");
MODULE_LICENSE("GPL v2");