/*
 * Copyright (C) 2015-2016 Socionext Inc.
 *   Author: Masahiro Yamada <yamada.masahiro@socionext.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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#define pr_fmt(fmt)             "uniphier: " fmt

#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/log2.h>
#include <linux/of_address.h>
#include <linux/slab.h>
#include <asm/hardware/cache-uniphier.h>
#include <asm/outercache.h>

/* control registers */
#define UNIPHIER_SSCC           0x0     /* Control Register */
#define    UNIPHIER_SSCC_BST                    BIT(20) /* UCWG burst read */
#define    UNIPHIER_SSCC_ACT                    BIT(19) /* Inst-Data separate */
#define    UNIPHIER_SSCC_WTG                    BIT(18) /* WT gathering on */
#define    UNIPHIER_SSCC_PRD                    BIT(17) /* enable pre-fetch */
#define    UNIPHIER_SSCC_ON                     BIT(0)  /* enable cache */
#define UNIPHIER_SSCLPDAWCR     0x30    /* Unified/Data Active Way Control */
#define UNIPHIER_SSCLPIAWCR     0x34    /* Instruction Active Way Control */

/* revision registers */
#define UNIPHIER_SSCID          0x0     /* ID Register */

/* operation registers */
#define UNIPHIER_SSCOPE         0x244   /* Cache Operation Primitive Entry */
#define    UNIPHIER_SSCOPE_CM_INV               0x0     /* invalidate */
#define    UNIPHIER_SSCOPE_CM_CLEAN             0x1     /* clean */
#define    UNIPHIER_SSCOPE_CM_FLUSH             0x2     /* flush */
#define    UNIPHIER_SSCOPE_CM_SYNC              0x8     /* sync (drain bufs) */
#define    UNIPHIER_SSCOPE_CM_FLUSH_PREFETCH    0x9     /* flush p-fetch buf */
#define UNIPHIER_SSCOQM         0x248   /* Cache Operation Queue Mode */
#define    UNIPHIER_SSCOQM_S_MASK               (0x3 << 17)
#define    UNIPHIER_SSCOQM_S_RANGE              (0x0 << 17)
#define    UNIPHIER_SSCOQM_S_ALL                (0x1 << 17)
#define    UNIPHIER_SSCOQM_CE                   BIT(15) /* notify completion */
#define    UNIPHIER_SSCOQM_CM_INV               0x0     /* invalidate */
#define    UNIPHIER_SSCOQM_CM_CLEAN             0x1     /* clean */
#define    UNIPHIER_SSCOQM_CM_FLUSH             0x2     /* flush */
#define UNIPHIER_SSCOQAD        0x24c   /* Cache Operation Queue Address */
#define UNIPHIER_SSCOQSZ        0x250   /* Cache Operation Queue Size */
#define UNIPHIER_SSCOPPQSEF     0x25c   /* Cache Operation Queue Set Complete*/
#define    UNIPHIER_SSCOPPQSEF_FE               BIT(1)
#define    UNIPHIER_SSCOPPQSEF_OE               BIT(0)
#define UNIPHIER_SSCOLPQS       0x260   /* Cache Operation Queue Status */
#define    UNIPHIER_SSCOLPQS_EF                 BIT(2)
#define    UNIPHIER_SSCOLPQS_EST                BIT(1)
#define    UNIPHIER_SSCOLPQS_QST                BIT(0)

/* Is the operation region specified by address range? */
#define UNIPHIER_SSCOQM_S_IS_RANGE(op) \
                ((op & UNIPHIER_SSCOQM_S_MASK) == UNIPHIER_SSCOQM_S_RANGE)

/**
 * uniphier_cache_data - UniPhier outer cache specific data
 *
 * @ctrl_base: virtual base address of control registers
 * @rev_base: virtual base address of revision registers
 * @op_base: virtual base address of operation registers
 * @way_mask: each bit specifies if the way is present
 * @nsets: number of associativity sets
 * @line_size: line size in bytes
 * @range_op_max_size: max size that can be handled by a single range operation
 * @list: list node to include this level in the whole cache hierarchy
 */
struct uniphier_cache_data {
        void __iomem *ctrl_base;
        void __iomem *rev_base;
        void __iomem *op_base;
        void __iomem *way_ctrl_base;
        u32 way_mask;
        u32 nsets;
        u32 line_size;
        u32 range_op_max_size;
        struct list_head list;
};

/*
 * List of the whole outer cache hierarchy.  This list is only modified during
 * the early boot stage, so no mutex is taken for the access to the list.
 */
static LIST_HEAD(uniphier_cache_list);

/**
 * __uniphier_cache_sync - perform a sync point for a particular cache level
 *
 * @data: cache controller specific data
 */
static void __uniphier_cache_sync(struct uniphier_cache_data *data)
{
        /* This sequence need not be atomic.  Do not disable IRQ. */
        writel_relaxed(UNIPHIER_SSCOPE_CM_SYNC,
                       data->op_base + UNIPHIER_SSCOPE);
        /* need a read back to confirm */
        readl_relaxed(data->op_base + UNIPHIER_SSCOPE);
}

/**
 * __uniphier_cache_maint_common - run a queue operation for a particular level
 *
 * @data: cache controller specific data
 * @start: start address of range operation (don't care for "all" operation)
 * @size: data size of range operation (don't care for "all" operation)
 * @operation: flags to specify the desired cache operation
 */
static void __uniphier_cache_maint_common(struct uniphier_cache_data *data,
                                          unsigned long start,
                                          unsigned long size,
                                          u32 operation)
{
        unsigned long flags;

        /*
         * No spin lock is necessary here because:
         *
         * [1] This outer cache controller is able to accept maintenance
         * operations from multiple CPUs at a time in an SMP system; if a
         * maintenance operation is under way and another operation is issued,
         * the new one is stored in the queue.  The controller performs one
         * operation after another.  If the queue is full, the status register,
         * UNIPHIER_SSCOPPQSEF, indicates that the queue registration has
         * failed.  The status registers, UNIPHIER_{SSCOPPQSEF, SSCOLPQS}, have
         * different instances for each CPU, i.e. each CPU can track the status
         * of the maintenance operations triggered by itself.
         *
         * [2] The cache command registers, UNIPHIER_{SSCOQM, SSCOQAD, SSCOQSZ,
         * SSCOQWN}, are shared between multiple CPUs, but the hardware still
         * guarantees the registration sequence is atomic; the write access to
         * them are arbitrated by the hardware.  The first accessor to the
         * register, UNIPHIER_SSCOQM, holds the access right and it is released
         * by reading the status register, UNIPHIER_SSCOPPQSEF.  While one CPU
         * is holding the access right, other CPUs fail to register operations.
         * One CPU should not hold the access right for a long time, so local
         * IRQs should be disabled while the following sequence.
         */
        local_irq_save(flags);

        /* clear the complete notification flag */
        writel_relaxed(UNIPHIER_SSCOLPQS_EF, data->op_base + UNIPHIER_SSCOLPQS);

        do {
                /* set cache operation */
                writel_relaxed(UNIPHIER_SSCOQM_CE | operation,
                               data->op_base + UNIPHIER_SSCOQM);

                /* set address range if needed */
                if (likely(UNIPHIER_SSCOQM_S_IS_RANGE(operation))) {
                        writel_relaxed(start, data->op_base + UNIPHIER_SSCOQAD);
                        writel_relaxed(size, data->op_base + UNIPHIER_SSCOQSZ);
                }
        } while (unlikely(readl_relaxed(data->op_base + UNIPHIER_SSCOPPQSEF) &
                          (UNIPHIER_SSCOPPQSEF_FE | UNIPHIER_SSCOPPQSEF_OE)));

        /* wait until the operation is completed */
        while (likely(readl_relaxed(data->op_base + UNIPHIER_SSCOLPQS) !=
                      UNIPHIER_SSCOLPQS_EF))
                cpu_relax();

        local_irq_restore(flags);
}

static void __uniphier_cache_maint_all(struct uniphier_cache_data *data,
                                       u32 operation)
{
        __uniphier_cache_maint_common(data, 0, 0,
                                      UNIPHIER_SSCOQM_S_ALL | operation);

        __uniphier_cache_sync(data);
}

static void __uniphier_cache_maint_range(struct uniphier_cache_data *data,
                                         unsigned long start, unsigned long end,
                                         u32 operation)
{
        unsigned long size;

        /*
         * If the start address is not aligned,
         * perform a cache operation for the first cache-line
         */
        start = start & ~(data->line_size - 1);

        size = end - start;

        if (unlikely(size >= (unsigned long)(-data->line_size))) {
                /* this means cache operation for all range */
                __uniphier_cache_maint_all(data, operation);
                return;
        }

        /*
         * If the end address is not aligned,
         * perform a cache operation for the last cache-line
         */
        size = ALIGN(size, data->line_size);

        while (size) {
                unsigned long chunk_size = min_t(unsigned long, size,
                                                 data->range_op_max_size);

                __uniphier_cache_maint_common(data, start, chunk_size,
                                        UNIPHIER_SSCOQM_S_RANGE | operation);

                start += chunk_size;
                size -= chunk_size;
        }

        __uniphier_cache_sync(data);
}

static void __uniphier_cache_enable(struct uniphier_cache_data *data, bool on)
{
        u32 val = 0;

        if (on)
                val = UNIPHIER_SSCC_WTG | UNIPHIER_SSCC_PRD | UNIPHIER_SSCC_ON;

        writel_relaxed(val, data->ctrl_base + UNIPHIER_SSCC);
}

static void __init __uniphier_cache_set_active_ways(
                                        struct uniphier_cache_data *data)
{
        unsigned int cpu;

        for_each_possible_cpu(cpu)
                writel_relaxed(data->way_mask, data->way_ctrl_base + 4 * cpu);
}

static void uniphier_cache_maint_range(unsigned long start, unsigned long end,
                                       u32 operation)
{
        struct uniphier_cache_data *data;

        list_for_each_entry(data, &uniphier_cache_list, list)
                __uniphier_cache_maint_range(data, start, end, operation);
}

static void uniphier_cache_maint_all(u32 operation)
{
        struct uniphier_cache_data *data;

        list_for_each_entry(data, &uniphier_cache_list, list)
                __uniphier_cache_maint_all(data, operation);
}

static void uniphier_cache_inv_range(unsigned long start, unsigned long end)
{
        uniphier_cache_maint_range(start, end, UNIPHIER_SSCOQM_CM_INV);
}

static void uniphier_cache_clean_range(unsigned long start, unsigned long end)
{
        uniphier_cache_maint_range(start, end, UNIPHIER_SSCOQM_CM_CLEAN);
}

static void uniphier_cache_flush_range(unsigned long start, unsigned long end)
{
        uniphier_cache_maint_range(start, end, UNIPHIER_SSCOQM_CM_FLUSH);
}

static void __init uniphier_cache_inv_all(void)
{
        uniphier_cache_maint_all(UNIPHIER_SSCOQM_CM_INV);
}

static void uniphier_cache_flush_all(void)
{
        uniphier_cache_maint_all(UNIPHIER_SSCOQM_CM_FLUSH);
}

static void uniphier_cache_disable(void)
{
        struct uniphier_cache_data *data;

        list_for_each_entry_reverse(data, &uniphier_cache_list, list)
                __uniphier_cache_enable(data, false);

        uniphier_cache_flush_all();
}

static void __init uniphier_cache_enable(void)
{
        struct uniphier_cache_data *data;

        uniphier_cache_inv_all();

        list_for_each_entry(data, &uniphier_cache_list, list) {
                __uniphier_cache_enable(data, true);
                __uniphier_cache_set_active_ways(data);
        }
}

static void uniphier_cache_sync(void)
{
        struct uniphier_cache_data *data;

        list_for_each_entry(data, &uniphier_cache_list, list)
                __uniphier_cache_sync(data);
}

static const struct of_device_id uniphier_cache_match[] __initconst = {
        { .compatible = "socionext,uniphier-system-cache" },
        { /* sentinel */ }
};

static int __init __uniphier_cache_init(struct device_node *np,
                                        unsigned int *cache_level)
{
        struct uniphier_cache_data *data;
        u32 level, cache_size;
        struct device_node *next_np;
        int ret = 0;

        if (!of_match_node(uniphier_cache_match, np)) {
                pr_err("L%d: not compatible with uniphier cache\n",
                       *cache_level);
                return -EINVAL;
        }

        if (of_property_read_u32(np, "cache-level", &level)) {
                pr_err("L%d: cache-level is not specified\n", *cache_level);
                return -EINVAL;
        }

        if (level != *cache_level) {
                pr_err("L%d: cache-level is unexpected value %d\n",
                       *cache_level, level);
                return -EINVAL;
        }

        if (!of_property_read_bool(np, "cache-unified")) {
                pr_err("L%d: cache-unified is not specified\n", *cache_level);
                return -EINVAL;
        }

        data = kzalloc(sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        if (of_property_read_u32(np, "cache-line-size", &data->line_size) ||
            !is_power_of_2(data->line_size)) {
                pr_err("L%d: cache-line-size is unspecified or invalid\n",
                       *cache_level);
                ret = -EINVAL;
                goto err;
        }

        if (of_property_read_u32(np, "cache-sets", &data->nsets) ||
            !is_power_of_2(data->nsets)) {
                pr_err("L%d: cache-sets is unspecified or invalid\n",
                       *cache_level);
                ret = -EINVAL;
                goto err;
        }

        if (of_property_read_u32(np, "cache-size", &cache_size) ||
            cache_size == 0 || cache_size % (data->nsets * data->line_size)) {
                pr_err("L%d: cache-size is unspecified or invalid\n",
                       *cache_level);
                ret = -EINVAL;
                goto err;
        }

        data->way_mask = GENMASK(cache_size / data->nsets / data->line_size - 1,
                                 0);

        data->ctrl_base = of_iomap(np, 0);
        if (!data->ctrl_base) {
                pr_err("L%d: failed to map control register\n", *cache_level);
                ret = -ENOMEM;
                goto err;
        }

        data->rev_base = of_iomap(np, 1);
        if (!data->rev_base) {
                pr_err("L%d: failed to map revision register\n", *cache_level);
                ret = -ENOMEM;
                goto err;
        }

        data->op_base = of_iomap(np, 2);
        if (!data->op_base) {
                pr_err("L%d: failed to map operation register\n", *cache_level);
                ret = -ENOMEM;
                goto err;
        }

        data->way_ctrl_base = data->ctrl_base + 0xc00;

        if (*cache_level == 2) {
                u32 revision = readl(data->rev_base + UNIPHIER_SSCID);
                /*
                 * The size of range operation is limited to (1 << 22) or less
                 * for PH-sLD8 or older SoCs.
                 */
                if (revision <= 0x16)
                        data->range_op_max_size = (u32)1 << 22;

                /*
                 * Unfortunatly, the offset address of active way control base
                 * varies from SoC to SoC.
                 */
                switch (revision) {
                case 0x11:      /* sLD3 */
                        data->way_ctrl_base = data->ctrl_base + 0x870;
                        break;
                case 0x12:      /* LD4 */
                case 0x16:      /* sld8 */
                        data->way_ctrl_base = data->ctrl_base + 0x840;
                        break;
                default:
                        break;
                }
        }

        data->range_op_max_size -= data->line_size;

        INIT_LIST_HEAD(&data->list);
        list_add_tail(&data->list, &uniphier_cache_list); /* no mutex */

        /*
         * OK, this level has been successfully initialized.  Look for the next
         * level cache.  Do not roll back even if the initialization of the
         * next level cache fails because we want to continue with available
         * cache levels.
         */
        next_np = of_find_next_cache_node(np);
        if (next_np) {
                (*cache_level)++;
                ret = __uniphier_cache_init(next_np, cache_level);
        }
        of_node_put(next_np);

        return ret;
err:
        iounmap(data->op_base);
        iounmap(data->rev_base);
        iounmap(data->ctrl_base);
        kfree(data);

        return ret;
}

int __init uniphier_cache_init(void)
{
        struct device_node *np = NULL;
        unsigned int cache_level;
        int ret = 0;

        /* look for level 2 cache */
        while ((np = of_find_matching_node(np, uniphier_cache_match)))
                if (!of_property_read_u32(np, "cache-level", &cache_level) &&
                    cache_level == 2)
                        break;

        if (!np)
                return -ENODEV;

        ret = __uniphier_cache_init(np, &cache_level);
        of_node_put(np);

        if (ret) {
                /*
                 * Error out iif L2 initialization fails.  Continue with any
                 * error on L3 or outer because they are optional.
                 */
                if (cache_level == 2) {
                        pr_err("failed to initialize L2 cache\n");
                        return ret;
                }

                cache_level--;
                ret = 0;
        }

        outer_cache.inv_range = uniphier_cache_inv_range;
        outer_cache.clean_range = uniphier_cache_clean_range;
        outer_cache.flush_range = uniphier_cache_flush_range;
        outer_cache.flush_all = uniphier_cache_flush_all;
        outer_cache.disable = uniphier_cache_disable;
        outer_cache.sync = uniphier_cache_sync;

        uniphier_cache_enable();

        pr_info("enabled outer cache (cache level: %d)\n", cache_level);

        return ret;
}