// SPDX-License-Identifier: GPL-2.0-only
/*
 * PS3 FLASH ROM Storage Driver
 *
 * Copyright (C) 2007 Sony Computer Entertainment Inc.
 * Copyright 2007 Sony Corp.
 */

#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/module.h>

#include <asm/lv1call.h>
#include <asm/ps3stor.h>


#define DEVICE_NAME             "ps3flash"

#define FLASH_BLOCK_SIZE        (256*1024)


struct ps3flash_private {
        struct mutex mutex;     /* Bounce buffer mutex */
        u64 chunk_sectors;
        int tag;                /* Start sector of buffer, -1 if invalid */
        bool dirty;
};

static struct ps3_storage_device *ps3flash_dev;

static int ps3flash_read_write_sectors(struct ps3_storage_device *dev,
                                       u64 start_sector, int write)
{
        struct ps3flash_private *priv = ps3_system_bus_get_drvdata(&dev->sbd);
        u64 res = ps3stor_read_write_sectors(dev, dev->bounce_lpar,
                                             start_sector, priv->chunk_sectors,
                                             write);
        if (res) {
                dev_err(&dev->sbd.core, "%s:%u: %s failed 0x%llx\n", __func__,
                        __LINE__, write ? "write" : "read", res);
                return -EIO;
        }
        return 0;
}

static int ps3flash_writeback(struct ps3_storage_device *dev)
{
        struct ps3flash_private *priv = ps3_system_bus_get_drvdata(&dev->sbd);
        int res;

        if (!priv->dirty || priv->tag < 0)
                return 0;

        res = ps3flash_read_write_sectors(dev, priv->tag, 1);
        if (res)
                return res;

        priv->dirty = false;
        return 0;
}

static int ps3flash_fetch(struct ps3_storage_device *dev, u64 start_sector)
{
        struct ps3flash_private *priv = ps3_system_bus_get_drvdata(&dev->sbd);
        int res;

        if (start_sector == priv->tag)
                return 0;

        res = ps3flash_writeback(dev);
        if (res)
                return res;

        priv->tag = -1;

        res = ps3flash_read_write_sectors(dev, start_sector, 0);
        if (res)
                return res;

        priv->tag = start_sector;
        return 0;
}

static loff_t ps3flash_llseek(struct file *file, loff_t offset, int origin)
{
        struct ps3_storage_device *dev = ps3flash_dev;
        return generic_file_llseek_size(file, offset, origin, MAX_LFS_FILESIZE,
                        dev->regions[dev->region_idx].size*dev->blk_size);
}

static ssize_t ps3flash_read(char __user *userbuf, void *kernelbuf,
                             size_t count, loff_t *pos)
{
        struct ps3_storage_device *dev = ps3flash_dev;
        struct ps3flash_private *priv = ps3_system_bus_get_drvdata(&dev->sbd);
        u64 size, sector, offset;
        int res;
        size_t remaining, n;
        const void *src;

        dev_dbg(&dev->sbd.core,
                "%s:%u: Reading %zu bytes at position %lld to U0x%p/K0x%p\n",
                __func__, __LINE__, count, *pos, userbuf, kernelbuf);

        size = dev->regions[dev->region_idx].size*dev->blk_size;
        if (*pos >= size || !count)
                return 0;

        if (*pos + count > size) {
                dev_dbg(&dev->sbd.core,
                        "%s:%u Truncating count from %zu to %llu\n", __func__,
                        __LINE__, count, size - *pos);
                count = size - *pos;
        }

        sector = *pos / dev->bounce_size * priv->chunk_sectors;
        offset = *pos % dev->bounce_size;

        remaining = count;
        do {
                n = min_t(u64, remaining, dev->bounce_size - offset);
                src = dev->bounce_buf + offset;

                mutex_lock(&priv->mutex);

                res = ps3flash_fetch(dev, sector);
                if (res)
                        goto fail;

                dev_dbg(&dev->sbd.core,
                        "%s:%u: copy %lu bytes from 0x%p to U0x%p/K0x%p\n",
                        __func__, __LINE__, n, src, userbuf, kernelbuf);
                if (userbuf) {
                        if (copy_to_user(userbuf, src, n)) {
                                res = -EFAULT;
                                goto fail;
                        }
                        userbuf += n;
                }
                if (kernelbuf) {
                        memcpy(kernelbuf, src, n);
                        kernelbuf += n;
                }

                mutex_unlock(&priv->mutex);

                *pos += n;
                remaining -= n;
                sector += priv->chunk_sectors;
                offset = 0;
        } while (remaining > 0);

        return count;

fail:
        mutex_unlock(&priv->mutex);
        return res;
}

static ssize_t ps3flash_write(const char __user *userbuf,
                              const void *kernelbuf, size_t count, loff_t *pos)
{
        struct ps3_storage_device *dev = ps3flash_dev;
        struct ps3flash_private *priv = ps3_system_bus_get_drvdata(&dev->sbd);
        u64 size, sector, offset;
        int res = 0;
        size_t remaining, n;
        void *dst;

        dev_dbg(&dev->sbd.core,
                "%s:%u: Writing %zu bytes at position %lld from U0x%p/K0x%p\n",
                __func__, __LINE__, count, *pos, userbuf, kernelbuf);

        size = dev->regions[dev->region_idx].size*dev->blk_size;
        if (*pos >= size || !count)
                return 0;

        if (*pos + count > size) {
                dev_dbg(&dev->sbd.core,
                        "%s:%u Truncating count from %zu to %llu\n", __func__,
                        __LINE__, count, size - *pos);
                count = size - *pos;
        }

        sector = *pos / dev->bounce_size * priv->chunk_sectors;
        offset = *pos % dev->bounce_size;

        remaining = count;
        do {
                n = min_t(u64, remaining, dev->bounce_size - offset);
                dst = dev->bounce_buf + offset;

                mutex_lock(&priv->mutex);

                if (n != dev->bounce_size)
                        res = ps3flash_fetch(dev, sector);
                else if (sector != priv->tag)
                        res = ps3flash_writeback(dev);
                if (res)
                        goto fail;

                dev_dbg(&dev->sbd.core,
                        "%s:%u: copy %lu bytes from U0x%p/K0x%p to 0x%p\n",
                        __func__, __LINE__, n, userbuf, kernelbuf, dst);
                if (userbuf) {
                        if (copy_from_user(dst, userbuf, n)) {
                                res = -EFAULT;
                                goto fail;
                        }
                        userbuf += n;
                }
                if (kernelbuf) {
                        memcpy(dst, kernelbuf, n);
                        kernelbuf += n;
                }

                priv->tag = sector;
                priv->dirty = true;

                mutex_unlock(&priv->mutex);

                *pos += n;
                remaining -= n;
                sector += priv->chunk_sectors;
                offset = 0;
        } while (remaining > 0);

        return count;

fail:
        mutex_unlock(&priv->mutex);
        return res;
}

static ssize_t ps3flash_user_read(struct file *file, char __user *buf,
                                  size_t count, loff_t *pos)
{
        return ps3flash_read(buf, NULL, count, pos);
}

static ssize_t ps3flash_user_write(struct file *file, const char __user *buf,
                                   size_t count, loff_t *pos)
{
        return ps3flash_write(buf, NULL, count, pos);
}

static ssize_t ps3flash_kernel_read(void *buf, size_t count, loff_t pos)
{
        return ps3flash_read(NULL, buf, count, &pos);
}

static ssize_t ps3flash_kernel_write(const void *buf, size_t count,
                                     loff_t pos)
{
        ssize_t res;
        int wb;

        res = ps3flash_write(NULL, buf, count, &pos);
        if (res < 0)
                return res;

        /* Make kernel writes synchronous */
        wb = ps3flash_writeback(ps3flash_dev);
        if (wb)
                return wb;

        return res;
}

static int ps3flash_flush(struct file *file, fl_owner_t id)
{
        return ps3flash_writeback(ps3flash_dev);
}

static int ps3flash_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{
        struct inode *inode = file_inode(file);
        int err;
        inode_lock(inode);
        err = ps3flash_writeback(ps3flash_dev);
        inode_unlock(inode);
        return err;
}

static irqreturn_t ps3flash_interrupt(int irq, void *data)
{
        struct ps3_storage_device *dev = data;
        int res;
        u64 tag, status;

        res = lv1_storage_get_async_status(dev->sbd.dev_id, &tag, &status);

        if (tag != dev->tag)
                dev_err(&dev->sbd.core,
                        "%s:%u: tag mismatch, got %llx, expected %llx\n",
                        __func__, __LINE__, tag, dev->tag);

        if (res) {
                dev_err(&dev->sbd.core, "%s:%u: res=%d status=0x%llx\n",
                        __func__, __LINE__, res, status);
        } else {
                dev->lv1_status = status;
                complete(&dev->done);
        }
        return IRQ_HANDLED;
}

static const struct file_operations ps3flash_fops = {
        .owner  = THIS_MODULE,
        .llseek = ps3flash_llseek,
        .read   = ps3flash_user_read,
        .write  = ps3flash_user_write,
        .flush  = ps3flash_flush,
        .fsync  = ps3flash_fsync,
};

static const struct ps3_os_area_flash_ops ps3flash_kernel_ops = {
        .read   = ps3flash_kernel_read,
        .write  = ps3flash_kernel_write,
};

static struct miscdevice ps3flash_misc = {
        .minor  = MISC_DYNAMIC_MINOR,
        .name   = DEVICE_NAME,
        .fops   = &ps3flash_fops,
};

static int ps3flash_probe(struct ps3_system_bus_device *_dev)
{
        struct ps3_storage_device *dev = to_ps3_storage_device(&_dev->core);
        struct ps3flash_private *priv;
        int error;
        unsigned long tmp;

        tmp = dev->regions[dev->region_idx].start*dev->blk_size;
        if (tmp % FLASH_BLOCK_SIZE) {
                dev_err(&dev->sbd.core,
                        "%s:%u region start %lu is not aligned\n", __func__,
                        __LINE__, tmp);
                return -EINVAL;
        }
        tmp = dev->regions[dev->region_idx].size*dev->blk_size;
        if (tmp % FLASH_BLOCK_SIZE) {
                dev_err(&dev->sbd.core,
                        "%s:%u region size %lu is not aligned\n", __func__,
                        __LINE__, tmp);
                return -EINVAL;
        }

        /* use static buffer, kmalloc cannot allocate 256 KiB */
        if (!ps3flash_bounce_buffer.address)
                return -ENODEV;

        if (ps3flash_dev) {
                dev_err(&dev->sbd.core,
                        "Only one FLASH device is supported\n");
                return -EBUSY;
        }

        ps3flash_dev = dev;

        priv = kzalloc_obj(*priv);
        if (!priv) {
                error = -ENOMEM;
                goto fail;
        }

        ps3_system_bus_set_drvdata(&dev->sbd, priv);
        mutex_init(&priv->mutex);
        priv->tag = -1;

        dev->bounce_size = ps3flash_bounce_buffer.size;
        dev->bounce_buf = ps3flash_bounce_buffer.address;
        priv->chunk_sectors = dev->bounce_size / dev->blk_size;

        error = ps3stor_setup(dev, ps3flash_interrupt);
        if (error)
                goto fail_free_priv;

        ps3flash_misc.parent = &dev->sbd.core;
        error = misc_register(&ps3flash_misc);
        if (error) {
                dev_err(&dev->sbd.core, "%s:%u: misc_register failed %d\n",
                        __func__, __LINE__, error);
                goto fail_teardown;
        }

        dev_info(&dev->sbd.core, "%s:%u: registered misc device %d\n",
                 __func__, __LINE__, ps3flash_misc.minor);

        ps3_os_area_flash_register(&ps3flash_kernel_ops);
        return 0;

fail_teardown:
        ps3stor_teardown(dev);
fail_free_priv:
        kfree(priv);
        ps3_system_bus_set_drvdata(&dev->sbd, NULL);
fail:
        ps3flash_dev = NULL;
        return error;
}

static void ps3flash_remove(struct ps3_system_bus_device *_dev)
{
        struct ps3_storage_device *dev = to_ps3_storage_device(&_dev->core);

        ps3_os_area_flash_register(NULL);
        misc_deregister(&ps3flash_misc);
        ps3stor_teardown(dev);
        kfree(ps3_system_bus_get_drvdata(&dev->sbd));
        ps3_system_bus_set_drvdata(&dev->sbd, NULL);
        ps3flash_dev = NULL;
}


static struct ps3_system_bus_driver ps3flash = {
        .match_id       = PS3_MATCH_ID_STOR_FLASH,
        .core.name      = DEVICE_NAME,
        .core.owner     = THIS_MODULE,
        .probe          = ps3flash_probe,
        .remove         = ps3flash_remove,
        .shutdown       = ps3flash_remove,
};


static int __init ps3flash_init(void)
{
        return ps3_system_bus_driver_register(&ps3flash);
}

static void __exit ps3flash_exit(void)
{
        ps3_system_bus_driver_unregister(&ps3flash);
}

module_init(ps3flash_init);
module_exit(ps3flash_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("PS3 FLASH ROM Storage Driver");
MODULE_AUTHOR("Sony Corporation");
MODULE_ALIAS(PS3_MODULE_ALIAS_STOR_FLASH);