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ps3flash.c

/*
 * PS3 FLASH ROM Storage Driver
 *
 * Copyright (C) 2007 Sony Computer Entertainment Inc.
 * Copyright 2007 Sony Corp.
 *
 * 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; version 2 of the License.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/uaccess.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 */
};

static struct ps3_storage_device *ps3flash_dev;

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

static ssize_t ps3flash_read_sectors(struct ps3_storage_device *dev,
                             u64 start_sector, u64 sectors,
                             unsigned int sector_offset)
{
      u64 max_sectors, lpar;

      max_sectors = dev->bounce_size / dev->blk_size;
      if (sectors > max_sectors) {
            dev_dbg(&dev->sbd.core, "%s:%u Limiting sectors to %lu\n",
                  __func__, __LINE__, max_sectors);
            sectors = max_sectors;
      }

      lpar = dev->bounce_lpar + sector_offset * dev->blk_size;
      return ps3flash_read_write_sectors(dev, lpar, start_sector, sectors,
                                 0);
}

static ssize_t ps3flash_write_chunk(struct ps3_storage_device *dev,
                            u64 start_sector)
{
       u64 sectors = dev->bounce_size / dev->blk_size;
       return ps3flash_read_write_sectors(dev, dev->bounce_lpar, start_sector,
                                sectors, 1);
}

static loff_t ps3flash_llseek(struct file *file, loff_t offset, int origin)
{
      struct ps3_storage_device *dev = ps3flash_dev;
      loff_t res;

      mutex_lock(&file->f_mapping->host->i_mutex);
      switch (origin) {
      case 1:
            offset += file->f_pos;
            break;
      case 2:
            offset += dev->regions[dev->region_idx].size*dev->blk_size;
            break;
      }
      if (offset < 0) {
            res = -EINVAL;
            goto out;
      }

      file->f_pos = offset;
      res = file->f_pos;

out:
      mutex_unlock(&file->f_mapping->host->i_mutex);
      return res;
}

static ssize_t ps3flash_read(struct file *file, char __user *buf, size_t count,
                       loff_t *pos)
{
      struct ps3_storage_device *dev = ps3flash_dev;
      struct ps3flash_private *priv = dev->sbd.core.driver_data;
      u64 size, start_sector, end_sector, offset;
      ssize_t sectors_read;
      size_t remaining, n;

      dev_dbg(&dev->sbd.core,
            "%s:%u: Reading %zu bytes at position %lld to user 0x%p\n",
            __func__, __LINE__, count, *pos, buf);

      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;
      }

      start_sector = *pos / dev->blk_size;
      offset = *pos % dev->blk_size;
      end_sector = DIV_ROUND_UP(*pos + count, dev->blk_size);

      remaining = count;
      do {
            mutex_lock(&priv->mutex);

            sectors_read = ps3flash_read_sectors(dev, start_sector,
                                         end_sector-start_sector,
                                         0);
            if (sectors_read < 0) {
                  mutex_unlock(&priv->mutex);
                  goto fail;
            }

            n = min(remaining, sectors_read*dev->blk_size-offset);
            dev_dbg(&dev->sbd.core,
                  "%s:%u: copy %lu bytes from 0x%p to user 0x%p\n",
                  __func__, __LINE__, n, dev->bounce_buf+offset, buf);
            if (copy_to_user(buf, dev->bounce_buf+offset, n)) {
                  mutex_unlock(&priv->mutex);
                  sectors_read = -EFAULT;
                  goto fail;
            }

            mutex_unlock(&priv->mutex);

            *pos += n;
            buf += n;
            remaining -= n;
            start_sector += sectors_read;
            offset = 0;
      } while (remaining > 0);

      return count;

fail:
      return sectors_read;
}

static ssize_t ps3flash_write(struct file *file, const char __user *buf,
                        size_t count, loff_t *pos)
{
      struct ps3_storage_device *dev = ps3flash_dev;
      struct ps3flash_private *priv = dev->sbd.core.driver_data;
      u64 size, chunk_sectors, start_write_sector, end_write_sector,
          end_read_sector, start_read_sector, head, tail, offset;
      ssize_t res;
      size_t remaining, n;
      unsigned int sec_off;

      dev_dbg(&dev->sbd.core,
            "%s:%u: Writing %zu bytes at position %lld from user 0x%p\n",
            __func__, __LINE__, count, *pos, buf);

      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;
      }

      chunk_sectors = dev->bounce_size / dev->blk_size;

      start_write_sector = *pos / dev->bounce_size * chunk_sectors;
      offset = *pos % dev->bounce_size;
      end_write_sector = DIV_ROUND_UP(*pos + count, dev->bounce_size) *
                     chunk_sectors;

      end_read_sector = DIV_ROUND_UP(*pos, dev->blk_size);
      start_read_sector = (*pos + count) / dev->blk_size;

      /*
       * As we have to write in 256 KiB chunks, while we can read in blk_size
       * (usually 512 bytes) chunks, we perform the following steps:
       *   1. Read from start_write_sector to end_read_sector ("head")
       *   2. Read from start_read_sector to end_write_sector ("tail")
       *   3. Copy data to buffer
       *   4. Write from start_write_sector to end_write_sector
       * All of this is complicated by using only one 256 KiB bounce buffer.
       */

      head = end_read_sector - start_write_sector;
      tail = end_write_sector - start_read_sector;

      remaining = count;
      do {
            mutex_lock(&priv->mutex);

            if (end_read_sector >= start_read_sector) {
                  /* Merge head and tail */
                  dev_dbg(&dev->sbd.core,
                        "Merged head and tail: %lu sectors at %lu\n",
                        chunk_sectors, start_write_sector);
                  res = ps3flash_read_sectors(dev, start_write_sector,
                                        chunk_sectors, 0);
                  if (res < 0)
                        goto fail;
            } else {
                  if (head) {
                        /* Read head */
                        dev_dbg(&dev->sbd.core,
                              "head: %lu sectors at %lu\n", head,
                              start_write_sector);
                        res = ps3flash_read_sectors(dev,
                                              start_write_sector,
                                              head, 0);
                        if (res < 0)
                              goto fail;
                  }
                  if (start_read_sector <
                      start_write_sector+chunk_sectors) {
                        /* Read tail */
                        dev_dbg(&dev->sbd.core,
                              "tail: %lu sectors at %lu\n", tail,
                              start_read_sector);
                        sec_off = start_read_sector-start_write_sector;
                        res = ps3flash_read_sectors(dev,
                                              start_read_sector,
                                              tail, sec_off);
                        if (res < 0)
                              goto fail;
                  }
            }

            n = min(remaining, dev->bounce_size-offset);
            dev_dbg(&dev->sbd.core,
                  "%s:%u: copy %lu bytes from user 0x%p to 0x%p\n",
                  __func__, __LINE__, n, buf, dev->bounce_buf+offset);
            if (copy_from_user(dev->bounce_buf+offset, buf, n)) {
                  res = -EFAULT;
                  goto fail;
            }

            res = ps3flash_write_chunk(dev, start_write_sector);
            if (res < 0)
                  goto fail;

            mutex_unlock(&priv->mutex);

            *pos += n;
            buf += n;
            remaining -= n;
            start_write_sector += chunk_sectors;
            head = 0;
            offset = 0;
      } while (remaining > 0);

      return count;

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


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 %lx, expected %lx\n",
                  __func__, __LINE__, tag, dev->tag);

      if (res) {
            dev_err(&dev->sbd.core, "%s:%u: res=%d status=0x%lx\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_read,
      .write      = ps3flash_write,
};

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

static int __devinit 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(sizeof(*priv), GFP_KERNEL);
      if (!priv) {
            error = -ENOMEM;
            goto fail;
      }

      dev->sbd.core.driver_data = priv;
      mutex_init(&priv->mutex);

      dev->bounce_size = ps3flash_bounce_buffer.size;
      dev->bounce_buf = ps3flash_bounce_buffer.address;

      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);
      return 0;

fail_teardown:
      ps3stor_teardown(dev);
fail_free_priv:
      kfree(priv);
      dev->sbd.core.driver_data = NULL;
fail:
      ps3flash_dev = NULL;
      return error;
}

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

      misc_deregister(&ps3flash_misc);
      ps3stor_teardown(dev);
      kfree(dev->sbd.core.driver_data);
      dev->sbd.core.driver_data = NULL;
      ps3flash_dev = NULL;
      return 0;
}


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);

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