/*
 * 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/blk-mq.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 blk_mq_tag_set tag_set;
	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\n",
			__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 blk_status_t 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\n",
		__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\n",
		__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\n", __func__,
			__LINE__, op, res);
		return BLK_STS_IOERR;
	}

	priv->req = req;
	return BLK_STS_OK;
}

static blk_status_t 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\n", __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\n",
			__func__, __LINE__, res);
		return BLK_STS_IOERR;
	}

	priv->req = req;
	return BLK_STS_OK;
}

static blk_status_t ps3disk_do_request(struct ps3_storage_device *dev,
				       struct request *req)
{
	dev_dbg(&dev->sbd.core, "%s:%u\n", __func__, __LINE__);

	switch (req_op(req)) {
	case REQ_OP_FLUSH:
		return ps3disk_submit_flush_request(dev, req);
	case REQ_OP_READ:
	case REQ_OP_WRITE:
		return ps3disk_submit_request_sg(dev, req);
	default:
		blk_dump_rq_flags(req, DEVICE_NAME " bad request");
		return BLK_STS_IOERR;
	}
}

static blk_status_t ps3disk_queue_rq(struct blk_mq_hw_ctx *hctx,
				     const struct blk_mq_queue_data *bd)
{
	struct request_queue *q = hctx->queue;
	struct ps3_storage_device *dev = q->queuedata;
	struct ps3disk_private *priv = ps3_system_bus_get_drvdata(&dev->sbd);
	blk_status_t ret;

	blk_mq_start_request(bd->rq);

	spin_lock_irq(&priv->lock);
	ret = ps3disk_do_request(dev, bd->rq);
	spin_unlock_irq(&priv->lock);

	return ret;
}

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;
	blk_status_t 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\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);
		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\n", __func__,
			__LINE__);
		dev->lv1_status = status;
		complete(&dev->done);
		return IRQ_HANDLED;
	}

	if (req_op(req) == REQ_OP_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\n", __func__,
			__LINE__, op, status);
		error = BLK_STS_IOERR;
	} else {
		dev_dbg(&dev->sbd.core, "%s:%u: %s completed\n", __func__,
			__LINE__, op);
		error = 0;
		if (read)
			ps3disk_scatter_gather(dev, req, 0);
	}

	spin_lock(&priv->lock);
	priv->req = NULL;
	blk_mq_end_request(req, error);
	spin_unlock(&priv->lock);

	blk_mq_run_hw_queues(priv->queue, true);
	return IRQ_HANDLED;
}

static int ps3disk_sync_cache(struct ps3_storage_device *dev)
{
	u64 res;

	dev_dbg(&dev->sbd.core, "%s:%u: sync cache\n", __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\n",
			__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\n", __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\n",
			__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 const struct blk_mq_ops ps3disk_mq_ops = {
	.queue_rq	= ps3disk_queue_rq,
};

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\n", __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\n", __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_mq_init_sq_queue(&priv->tag_set, &ps3disk_mq_ops, 1,
					BLK_MQ_F_SHOULD_MERGE);
	if (IS_ERR(queue)) {
		dev_err(&dev->sbd.core, "%s:%u: blk_mq_init_queue failed\n",
			__func__, __LINE__);
		error = PTR_ERR(queue);
		goto fail_teardown;
	}

	priv->queue = queue;
	queue->queuedata = dev;

	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_write_cache(queue, true, false);

	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\n", __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;
	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)\n",
		 gendisk->disk_name, priv->model, priv->raw_capacity >> 11,
		 get_capacity(gendisk) >> 11);

	device_add_disk(&dev->sbd.core, gendisk, NULL);
	return 0;

fail_cleanup_queue:
	blk_cleanup_queue(queue);
	blk_mq_free_tag_set(&priv->tag_set);
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);
	blk_mq_free_tag_set(&priv->tag_set);
	put_disk(priv->gendisk);
	dev_notice(&dev->sbd.core, "Synchronizing disk cache\n");
	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\n", __func__,
		       __LINE__, error);
		return error;
	}
	ps3disk_major = error;

	pr_info("%s:%u: registered block device major %d\n", __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);