/*
   * PS3 Disk 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/ata.h>
  #include <linux/blkdev.h>
  #include <linux/slab.h>
  #include <linux/module.h>
  
  #include <asm/lv1call.h>
  #include <asm/ps3stor.h>
  #include <asm/firmware.h>
  
  
  #define DEVICE_NAME		"ps3disk"
  
  #define BOUNCE_SIZE		(64*1024)
  
  #define PS3DISK_MAX_DISKS	16
  #define PS3DISK_MINORS		16
  
  
  #define PS3DISK_NAME		"ps3d%c"
  
  
  struct ps3disk_private {
  	spinlock_t lock;		/* Request queue spinlock */
  	struct request_queue *queue;
  	struct gendisk *gendisk;
  	unsigned int blocking_factor;
  	struct request *req;
  	u64 raw_capacity;
  	unsigned char model[ATA_ID_PROD_LEN+1];
  };
  
  
  #define LV1_STORAGE_SEND_ATA_COMMAND	(2)
  #define LV1_STORAGE_ATA_HDDOUT		(0x23)
  
  struct lv1_ata_cmnd_block {
  	u16	features;
  	u16	sector_count;
  	u16	LBA_low;
  	u16	LBA_mid;
  	u16	LBA_high;
  	u8	device;
  	u8	command;
  	u32	is_ext;
  	u32	proto;
  	u32	in_out;
  	u32	size;
  	u64	buffer;
  	u32	arglen;
  };
  
  enum lv1_ata_proto {
  	NON_DATA_PROTO     = 0,
  	PIO_DATA_IN_PROTO  = 1,
  	PIO_DATA_OUT_PROTO = 2,
  	DMA_PROTO = 3
  };
  
  enum lv1_ata_in_out {
  	DIR_WRITE = 0,			/* memory -> device */
  	DIR_READ = 1			/* device -> memory */
  };
  
  static int ps3disk_major;
  
  
  static const struct block_device_operations ps3disk_fops = {
  	.owner		= THIS_MODULE,
  };
  
  
  static void ps3disk_scatter_gather(struct ps3_storage_device *dev,
  				   struct request *req, int gather)
  {
  	unsigned int offset = 0;
  	struct req_iterator iter;
  	struct bio_vec bvec;
  	unsigned int i = 0;
  	size_t size;
  	void *buf;
  
  	rq_for_each_segment(bvec, req, iter) {
  		unsigned long flags;
  		dev_dbg(&dev->sbd.core, "%s:%u: bio %u: %u sectors from %lu
  ",
  			__func__, __LINE__, i, bio_sectors(iter.bio),
  			iter.bio->bi_iter.bi_sector);
  
  		size = bvec.bv_len;
  		buf = bvec_kmap_irq(&bvec, &flags);
  		if (gather)
  			memcpy(dev->bounce_buf+offset, buf, size);
  		else
  			memcpy(buf, dev->bounce_buf+offset, size);
  		offset += size;
  		flush_kernel_dcache_page(bvec.bv_page);
  		bvec_kunmap_irq(buf, &flags);
  		i++;
  	}
  }
  
  static int ps3disk_submit_request_sg(struct ps3_storage_device *dev,
  				     struct request *req)
  {
  	struct ps3disk_private *priv = ps3_system_bus_get_drvdata(&dev->sbd);
  	int write = rq_data_dir(req), res;
  	const char *op = write ? "write" : "read";
  	u64 start_sector, sectors;
  	unsigned int region_id = dev->regions[dev->region_idx].id;
  
  #ifdef DEBUG
  	unsigned int n = 0;
  	struct bio_vec bv;
  	struct req_iterator iter;
  
  	rq_for_each_segment(bv, req, iter)
  		n++;
  	dev_dbg(&dev->sbd.core,
  		"%s:%u: %s req has %u bvecs for %u sectors
  ",
  		__func__, __LINE__, op, n, blk_rq_sectors(req));
  #endif
  
  	start_sector = blk_rq_pos(req) * priv->blocking_factor;
  	sectors = blk_rq_sectors(req) * priv->blocking_factor;
  	dev_dbg(&dev->sbd.core, "%s:%u: %s %llu sectors starting at %llu
  ",
  		__func__, __LINE__, op, sectors, start_sector);
  
  	if (write) {
  		ps3disk_scatter_gather(dev, req, 1);
  
  		res = lv1_storage_write(dev->sbd.dev_id, region_id,
  					start_sector, sectors, 0,
  					dev->bounce_lpar, &dev->tag);
  	} else {
  		res = lv1_storage_read(dev->sbd.dev_id, region_id,
  				       start_sector, sectors, 0,
  				       dev->bounce_lpar, &dev->tag);
  	}
  	if (res) {
  		dev_err(&dev->sbd.core, "%s:%u: %s failed %d
  ", __func__,
  			__LINE__, op, res);
  		__blk_end_request_all(req, -EIO);
  		return 0;
  	}
  
  	priv->req = req;
  	return 1;
  }
  
  static int ps3disk_submit_flush_request(struct ps3_storage_device *dev,
  					struct request *req)
  {
  	struct ps3disk_private *priv = ps3_system_bus_get_drvdata(&dev->sbd);
  	u64 res;
  
  	dev_dbg(&dev->sbd.core, "%s:%u: flush request
  ", __func__, __LINE__);
  
  	res = lv1_storage_send_device_command(dev->sbd.dev_id,
  					      LV1_STORAGE_ATA_HDDOUT, 0, 0, 0,
  					      0, &dev->tag);
  	if (res) {
  		dev_err(&dev->sbd.core, "%s:%u: sync cache failed 0x%llx
  ",
  			__func__, __LINE__, res);
  		__blk_end_request_all(req, -EIO);
  		return 0;
  	}
  
  	priv->req = req;
  	return 1;
  }
  
  static void ps3disk_do_request(struct ps3_storage_device *dev,
  			       struct request_queue *q)
  {
  	struct request *req;
  
  	dev_dbg(&dev->sbd.core, "%s:%u
  ", __func__, __LINE__);
  
  	while ((req = blk_fetch_request(q))) {
  		if (req->cmd_flags & REQ_FLUSH) {
  			if (ps3disk_submit_flush_request(dev, req))
  				break;
  		} else if (req->cmd_type == REQ_TYPE_FS) {
  			if (ps3disk_submit_request_sg(dev, req))
  				break;
  		} else {
  			blk_dump_rq_flags(req, DEVICE_NAME " bad request");
  			__blk_end_request_all(req, -EIO);
  			continue;
  		}
  	}
  }
  
  static void ps3disk_request(struct request_queue *q)
  {
  	struct ps3_storage_device *dev = q->queuedata;
  	struct ps3disk_private *priv = ps3_system_bus_get_drvdata(&dev->sbd);
  
  	if (priv->req) {
  		dev_dbg(&dev->sbd.core, "%s:%u busy
  ", __func__, __LINE__);
  		return;
  	}
  
  	ps3disk_do_request(dev, q);
  }
  
  static irqreturn_t ps3disk_interrupt(int irq, void *data)
  {
  	struct ps3_storage_device *dev = data;
  	struct ps3disk_private *priv;
  	struct request *req;
  	int res, read, error;
  	u64 tag, status;
  	const char *op;
  
  	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
  ",
  			__func__, __LINE__, tag, dev->tag);
  
  	if (res) {
  		dev_err(&dev->sbd.core, "%s:%u: res=%d status=0x%llx
  ",
  			__func__, __LINE__, res, status);
  		return IRQ_HANDLED;
  	}
  
  	priv = ps3_system_bus_get_drvdata(&dev->sbd);
  	req = priv->req;
  	if (!req) {
  		dev_dbg(&dev->sbd.core,
  			"%s:%u non-block layer request completed
  ", __func__,
  			__LINE__);
  		dev->lv1_status = status;
  		complete(&dev->done);
  		return IRQ_HANDLED;
  	}
  
  	if (req->cmd_flags & REQ_FLUSH) {
  		read = 0;
  		op = "flush";
  	} else {
  		read = !rq_data_dir(req);
  		op = read ? "read" : "write";
  	}
  	if (status) {
  		dev_dbg(&dev->sbd.core, "%s:%u: %s failed 0x%llx
  ", __func__,
  			__LINE__, op, status);
  		error = -EIO;
  	} else {
  		dev_dbg(&dev->sbd.core, "%s:%u: %s completed
  ", __func__,
  			__LINE__, op);
  		error = 0;
  		if (read)
  			ps3disk_scatter_gather(dev, req, 0);
  	}
  
  	spin_lock(&priv->lock);
  	__blk_end_request_all(req, error);
  	priv->req = NULL;
  	ps3disk_do_request(dev, priv->queue);
  	spin_unlock(&priv->lock);
  
  	return IRQ_HANDLED;
  }
  
  static int ps3disk_sync_cache(struct ps3_storage_device *dev)
  {
  	u64 res;
  
  	dev_dbg(&dev->sbd.core, "%s:%u: sync cache
  ", __func__, __LINE__);
  
  	res = ps3stor_send_command(dev, LV1_STORAGE_ATA_HDDOUT, 0, 0, 0, 0);
  	if (res) {
  		dev_err(&dev->sbd.core, "%s:%u: sync cache failed 0x%llx
  ",
  			__func__, __LINE__, res);
  		return -EIO;
  	}
  	return 0;
  }
  
  
  /* ATA helpers copied from drivers/ata/libata-core.c */
  
  static void swap_buf_le16(u16 *buf, unsigned int buf_words)
  {
  #ifdef __BIG_ENDIAN
  	unsigned int i;
  
  	for (i = 0; i < buf_words; i++)
  		buf[i] = le16_to_cpu(buf[i]);
  #endif /* __BIG_ENDIAN */
  }
  
  static u64 ata_id_n_sectors(const u16 *id)
  {
  	if (ata_id_has_lba(id)) {
  		if (ata_id_has_lba48(id))
  			return ata_id_u64(id, 100);
  		else
  			return ata_id_u32(id, 60);
  	} else {
  		if (ata_id_current_chs_valid(id))
  			return ata_id_u32(id, 57);
  		else
  			return id[1] * id[3] * id[6];
  	}
  }
  
  static void ata_id_string(const u16 *id, unsigned char *s, unsigned int ofs,
  			  unsigned int len)
  {
  	unsigned int c;
  
  	while (len > 0) {
  		c = id[ofs] >> 8;
  		*s = c;
  		s++;
  
  		c = id[ofs] & 0xff;
  		*s = c;
  		s++;
  
  		ofs++;
  		len -= 2;
  	}
  }
  
  static void ata_id_c_string(const u16 *id, unsigned char *s, unsigned int ofs,
  			    unsigned int len)
  {
  	unsigned char *p;
  
  	WARN_ON(!(len & 1));
  
  	ata_id_string(id, s, ofs, len - 1);
  
  	p = s + strnlen(s, len - 1);
  	while (p > s && p[-1] == ' ')
  		p--;
  	*p = '\0';
  }
  
  static int ps3disk_identify(struct ps3_storage_device *dev)
  {
  	struct ps3disk_private *priv = ps3_system_bus_get_drvdata(&dev->sbd);
  	struct lv1_ata_cmnd_block ata_cmnd;
  	u16 *id = dev->bounce_buf;
  	u64 res;
  
  	dev_dbg(&dev->sbd.core, "%s:%u: identify disk
  ", __func__, __LINE__);
  
  	memset(&ata_cmnd, 0, sizeof(struct lv1_ata_cmnd_block));
  	ata_cmnd.command = ATA_CMD_ID_ATA;
  	ata_cmnd.sector_count = 1;
  	ata_cmnd.size = ata_cmnd.arglen = ATA_ID_WORDS * 2;
  	ata_cmnd.buffer = dev->bounce_lpar;
  	ata_cmnd.proto = PIO_DATA_IN_PROTO;
  	ata_cmnd.in_out = DIR_READ;
  
  	res = ps3stor_send_command(dev, LV1_STORAGE_SEND_ATA_COMMAND,
  				   ps3_mm_phys_to_lpar(__pa(&ata_cmnd)),
  				   sizeof(ata_cmnd), ata_cmnd.buffer,
  				   ata_cmnd.arglen);
  	if (res) {
  		dev_err(&dev->sbd.core, "%s:%u: identify disk failed 0x%llx
  ",
  			__func__, __LINE__, res);
  		return -EIO;
  	}
  
  	swap_buf_le16(id, ATA_ID_WORDS);
  
  	/* All we're interested in are raw capacity and model name */
  	priv->raw_capacity = ata_id_n_sectors(id);
  	ata_id_c_string(id, priv->model, ATA_ID_PROD, sizeof(priv->model));
  	return 0;
  }
  
  static unsigned long ps3disk_mask;
  
  static DEFINE_MUTEX(ps3disk_mask_mutex);
  
  static int ps3disk_probe(struct ps3_system_bus_device *_dev)
  {
  	struct ps3_storage_device *dev = to_ps3_storage_device(&_dev->core);
  	struct ps3disk_private *priv;
  	int error;
  	unsigned int devidx;
  	struct request_queue *queue;
  	struct gendisk *gendisk;
  
  	if (dev->blk_size < 512) {
  		dev_err(&dev->sbd.core,
  			"%s:%u: cannot handle block size %llu
  ", __func__,
  			__LINE__, dev->blk_size);
  		return -EINVAL;
  	}
  
  	BUILD_BUG_ON(PS3DISK_MAX_DISKS > BITS_PER_LONG);
  	mutex_lock(&ps3disk_mask_mutex);
  	devidx = find_first_zero_bit(&ps3disk_mask, PS3DISK_MAX_DISKS);
  	if (devidx >= PS3DISK_MAX_DISKS) {
  		dev_err(&dev->sbd.core, "%s:%u: Too many disks
  ", __func__,
  			__LINE__);
  		mutex_unlock(&ps3disk_mask_mutex);
  		return -ENOSPC;
  	}
  	__set_bit(devidx, &ps3disk_mask);
  	mutex_unlock(&ps3disk_mask_mutex);
  
  	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
  	if (!priv) {
  		error = -ENOMEM;
  		goto fail;
  	}
  
  	ps3_system_bus_set_drvdata(_dev, priv);
  	spin_lock_init(&priv->lock);
  
  	dev->bounce_size = BOUNCE_SIZE;
  	dev->bounce_buf = kmalloc(BOUNCE_SIZE, GFP_DMA);
  	if (!dev->bounce_buf) {
  		error = -ENOMEM;
  		goto fail_free_priv;
  	}
  
  	error = ps3stor_setup(dev, ps3disk_interrupt);
  	if (error)
  		goto fail_free_bounce;
  
  	ps3disk_identify(dev);
  
  	queue = blk_init_queue(ps3disk_request, &priv->lock);
  	if (!queue) {
  		dev_err(&dev->sbd.core, "%s:%u: blk_init_queue failed
  ",
  			__func__, __LINE__);
  		error = -ENOMEM;
  		goto fail_teardown;
  	}
  
  	priv->queue = queue;
  	queue->queuedata = dev;
  
  	blk_queue_bounce_limit(queue, BLK_BOUNCE_HIGH);
  
  	blk_queue_max_hw_sectors(queue, dev->bounce_size >> 9);
  	blk_queue_segment_boundary(queue, -1UL);
  	blk_queue_dma_alignment(queue, dev->blk_size-1);
  	blk_queue_logical_block_size(queue, dev->blk_size);
  
  	blk_queue_flush(queue, REQ_FLUSH);
  
  	blk_queue_max_segments(queue, -1);
  	blk_queue_max_segment_size(queue, dev->bounce_size);
  
  	gendisk = alloc_disk(PS3DISK_MINORS);
  	if (!gendisk) {
  		dev_err(&dev->sbd.core, "%s:%u: alloc_disk failed
  ", __func__,
  			__LINE__);
  		error = -ENOMEM;
  		goto fail_cleanup_queue;
  	}
  
  	priv->gendisk = gendisk;
  	gendisk->major = ps3disk_major;
  	gendisk->first_minor = devidx * PS3DISK_MINORS;
  	gendisk->fops = &ps3disk_fops;
  	gendisk->queue = queue;
  	gendisk->private_data = dev;
  	gendisk->driverfs_dev = &dev->sbd.core;
  	snprintf(gendisk->disk_name, sizeof(gendisk->disk_name), PS3DISK_NAME,
  		 devidx+'a');
  	priv->blocking_factor = dev->blk_size >> 9;
  	set_capacity(gendisk,
  		     dev->regions[dev->region_idx].size*priv->blocking_factor);
  
  	dev_info(&dev->sbd.core,
  		 "%s is a %s (%llu MiB total, %lu MiB for OtherOS)
  ",
  		 gendisk->disk_name, priv->model, priv->raw_capacity >> 11,
  		 get_capacity(gendisk) >> 11);
  
  	add_disk(gendisk);
  	return 0;
  
  fail_cleanup_queue:
  	blk_cleanup_queue(queue);
  fail_teardown:
  	ps3stor_teardown(dev);
  fail_free_bounce:
  	kfree(dev->bounce_buf);
  fail_free_priv:
  	kfree(priv);
  	ps3_system_bus_set_drvdata(_dev, NULL);
  fail:
  	mutex_lock(&ps3disk_mask_mutex);
  	__clear_bit(devidx, &ps3disk_mask);
  	mutex_unlock(&ps3disk_mask_mutex);
  	return error;
  }
  
  static int ps3disk_remove(struct ps3_system_bus_device *_dev)
  {
  	struct ps3_storage_device *dev = to_ps3_storage_device(&_dev->core);
  	struct ps3disk_private *priv = ps3_system_bus_get_drvdata(&dev->sbd);
  
  	mutex_lock(&ps3disk_mask_mutex);
  	__clear_bit(MINOR(disk_devt(priv->gendisk)) / PS3DISK_MINORS,
  		    &ps3disk_mask);
  	mutex_unlock(&ps3disk_mask_mutex);
  	del_gendisk(priv->gendisk);
  	blk_cleanup_queue(priv->queue);
  	put_disk(priv->gendisk);
  	dev_notice(&dev->sbd.core, "Synchronizing disk cache
  ");
  	ps3disk_sync_cache(dev);
  	ps3stor_teardown(dev);
  	kfree(dev->bounce_buf);
  	kfree(priv);
  	ps3_system_bus_set_drvdata(_dev, NULL);
  	return 0;
  }
  
  static struct ps3_system_bus_driver ps3disk = {
  	.match_id	= PS3_MATCH_ID_STOR_DISK,
  	.core.name	= DEVICE_NAME,
  	.core.owner	= THIS_MODULE,
  	.probe		= ps3disk_probe,
  	.remove		= ps3disk_remove,
  	.shutdown	= ps3disk_remove,
  };
  
  
  static int __init ps3disk_init(void)
  {
  	int error;
  
  	if (!firmware_has_feature(FW_FEATURE_PS3_LV1))
  		return -ENODEV;
  
  	error = register_blkdev(0, DEVICE_NAME);
  	if (error <= 0) {
  		printk(KERN_ERR "%s:%u: register_blkdev failed %d
  ", __func__,
  		       __LINE__, error);
  		return error;
  	}
  	ps3disk_major = error;
  
  	pr_info("%s:%u: registered block device major %d
  ", __func__,
  		__LINE__, ps3disk_major);
  
  	error = ps3_system_bus_driver_register(&ps3disk);
  	if (error)
  		unregister_blkdev(ps3disk_major, DEVICE_NAME);
  
  	return error;
  }
  
  static void __exit ps3disk_exit(void)
  {
  	ps3_system_bus_driver_unregister(&ps3disk);
  	unregister_blkdev(ps3disk_major, DEVICE_NAME);
  }
  
  module_init(ps3disk_init);
  module_exit(ps3disk_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("PS3 Disk Storage Driver");
  MODULE_AUTHOR("Sony Corporation");
  MODULE_ALIAS(PS3_MODULE_ALIAS_STOR_DISK);