[S390] dasd: Add support for raw ECKD access.

Normal I/O operations through the DASD device driver give only access
to the data fields of an ECKD device even for track based I/O.
This patch extends the DASD device driver to give access to whole
ECKD tracks including count, key and data fields.

Signed-off-by: Stefan Haberland <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/include/asm/dasd.h

···
  * 0x02: use diag discipline (diag)
  * 0x04: set the device initially online (internal use only)
  * 0x08: enable ERP related logging
+ * 0x20: give access to raw eckd data
  */
 #define DASD_FEATURE_DEFAULT	     0x00
 #define DASD_FEATURE_READONLY	     0x01
···
 #define DASD_FEATURE_ERPLOG	     0x08
 #define DASD_FEATURE_FAILFAST	     0x10
 #define DASD_FEATURE_FAILONSLCK      0x20
+#define DASD_FEATURE_USERAW	     0x40
 
 #define DASD_PARTN_BITS 2
 

drivers/s390/block/dasd.c

···
 	device->state = DASD_STATE_ONLINE;
 	if (device->block) {
 		dasd_schedule_block_bh(device->block);
+		if ((device->features & DASD_FEATURE_USERAW)) {
+			disk = device->block->gdp;
+			kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
+			return 0;
+		}
 		disk = device->block->bdev->bd_disk;
 		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
 		while ((part = disk_part_iter_next(&piter)))
···
 			return rc;
 	}
 	device->state = DASD_STATE_READY;
-	if (device->block) {
+	if (device->block && !(device->features & DASD_FEATURE_USERAW)) {
 		disk = device->block->bdev->bd_disk;
 		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
 		while ((part = disk_part_iter_next(&piter)))
···
 {
 	int max;
 
-	blk_queue_logical_block_size(block->request_queue, block->bp_block);
-	max = block->base->discipline->max_blocks << block->s2b_shift;
+	if (block->base->features & DASD_FEATURE_USERAW) {
+		/*
+		 * the max_blocks value for raw_track access is 256
+		 * it is higher than the native ECKD value because we
+		 * only need one ccw per track
+		 * so the max_hw_sectors are
+		 * 2048 x 512B = 1024kB = 16 tracks
+		 */
+		max = 2048;
+	} else {
+		max = block->base->discipline->max_blocks << block->s2b_shift;
+	}
+	blk_queue_logical_block_size(block->request_queue,
+				     block->bp_block);
 	blk_queue_max_hw_sectors(block->request_queue, max);
 	blk_queue_max_segments(block->request_queue, -1L);
 	/* with page sized segments we can translate each segement into

drivers/s390/block/dasd_devmap.c

···
 			features |= DASD_FEATURE_READONLY;
 		else if (len == 4 && !strncmp(str, "diag", 4))
 			features |= DASD_FEATURE_USEDIAG;
+		else if (len == 3 && !strncmp(str, "raw", 3))
+			features |= DASD_FEATURE_USERAW;
 		else if (len == 6 && !strncmp(str, "erplog", 6))
 			features |= DASD_FEATURE_ERPLOG;
 		else if (len == 8 && !strncmp(str, "failfast", 8))
···
 	spin_lock(&dasd_devmap_lock);
 	/* Changing diag discipline flag is only allowed in offline state. */
 	rc = count;
-	if (!devmap->device) {
+	if (!devmap->device && !(devmap->features & DASD_FEATURE_USERAW)) {
 		if (val)
 			devmap->features |= DASD_FEATURE_USEDIAG;
 		else
···
 }
 
 static DEVICE_ATTR(use_diag, 0644, dasd_use_diag_show, dasd_use_diag_store);
+
+/*
+ * use_raw controls whether the driver should give access to raw eckd data or
+ * operate in standard mode
+ */
+static ssize_t
+dasd_use_raw_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct dasd_devmap *devmap;
+	int use_raw;
+
+	devmap = dasd_find_busid(dev_name(dev));
+	if (!IS_ERR(devmap))
+		use_raw = (devmap->features & DASD_FEATURE_USERAW) != 0;
+	else
+		use_raw = (DASD_FEATURE_DEFAULT & DASD_FEATURE_USERAW) != 0;
+	return sprintf(buf, use_raw ? "1\n" : "0\n");
+}
+
+static ssize_t
+dasd_use_raw_store(struct device *dev, struct device_attribute *attr,
+		    const char *buf, size_t count)
+{
+	struct dasd_devmap *devmap;
+	ssize_t rc;
+	unsigned long val;
+
+	devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
+	if (IS_ERR(devmap))
+		return PTR_ERR(devmap);
+
+	if ((strict_strtoul(buf, 10, &val) != 0) || val > 1)
+		return -EINVAL;
+
+	spin_lock(&dasd_devmap_lock);
+	/* Changing diag discipline flag is only allowed in offline state. */
+	rc = count;
+	if (!devmap->device && !(devmap->features & DASD_FEATURE_USEDIAG)) {
+		if (val)
+			devmap->features |= DASD_FEATURE_USERAW;
+		else
+			devmap->features &= ~DASD_FEATURE_USERAW;
+	} else
+		rc = -EPERM;
+	spin_unlock(&dasd_devmap_lock);
+	return rc;
+}
+
+static DEVICE_ATTR(raw_track_access, 0644, dasd_use_raw_show,
+		   dasd_use_raw_store);
 
 static ssize_t
 dasd_discipline_show(struct device *dev, struct device_attribute *attr,
···
 	&dev_attr_vendor.attr,
 	&dev_attr_uid.attr,
 	&dev_attr_use_diag.attr,
+	&dev_attr_raw_track_access.attr,
 	&dev_attr_eer_enabled.attr,
 	&dev_attr_erplog.attr,
 	&dev_attr_failfast.attr,

drivers/s390/block/dasd_eckd.c

···
 #define ECKD_F7(i) (i->factor7)
 #define ECKD_F8(i) (i->factor8)
 
+/*
+ * raw track access always map to 64k in memory
+ * so it maps to 16 blocks of 4k per track
+ */
+#define DASD_RAW_BLOCK_PER_TRACK 16
+#define DASD_RAW_BLOCKSIZE 4096
+/* 64k are 128 x 512 byte sectors  */
+#define DASD_RAW_SECTORS_PER_TRACK 128
+
 MODULE_LICENSE("GPL");
 
 static struct dasd_discipline dasd_eckd_discipline;
···
 		data->length = reclen;
 		data->operation.operation = 0x03;
 		break;
+	case DASD_ECKD_CCW_WRITE_FULL_TRACK:
+		data->operation.orientation = 0x0;
+		data->operation.operation = 0x3F;
+		data->extended_operation = 0x11;
+		data->length = 0;
+		data->extended_parameter_length = 0x02;
+		if (data->count > 8) {
+			data->extended_parameter[0] = 0xFF;
+			data->extended_parameter[1] = 0xFF;
+			data->extended_parameter[1] <<= (16 - count);
+		} else {
+			data->extended_parameter[0] = 0xFF;
+			data->extended_parameter[0] <<= (8 - count);
+			data->extended_parameter[1] = 0x00;
+		}
+		data->sector = 0xFF;
+		break;
 	case DASD_ECKD_CCW_WRITE_TRACK_DATA:
 		data->auxiliary.length_valid = 0x1;
 		data->length = reclen;	/* not tlf, as one might think */
···
 		break;
 	case DASD_ECKD_CCW_READ_COUNT:
 		data->operation.operation = 0x06;
+		break;
+	case DASD_ECKD_CCW_READ_TRACK:
+		data->operation.orientation = 0x1;
+		data->operation.operation = 0x0C;
+		data->extended_parameter_length = 0;
+		data->sector = 0xFF;
 		break;
 	case DASD_ECKD_CCW_READ_TRACK_DATA:
 		data->auxiliary.length_valid = 0x1;
···
 
 	ccw->cmd_code = DASD_ECKD_CCW_PFX;
 	ccw->flags = 0;
-	ccw->count = sizeof(*pfxdata);
-	ccw->cda = (__u32) __pa(pfxdata);
+	if (cmd == DASD_ECKD_CCW_WRITE_FULL_TRACK) {
+		ccw->count = sizeof(*pfxdata) + 2;
+		ccw->cda = (__u32) __pa(pfxdata);
+		memset(pfxdata, 0, sizeof(*pfxdata) + 2);
+	} else {
+		ccw->count = sizeof(*pfxdata);
+		ccw->cda = (__u32) __pa(pfxdata);
+		memset(pfxdata, 0, sizeof(*pfxdata));
+	}
 
-	memset(pfxdata, 0, sizeof(*pfxdata));
 	/* prefix data */
 	if (format > 1) {
 		DBF_DEV_EVENT(DBF_ERR, basedev,
···
 		dedata->mask.perm = 0x1;
 		dedata->attributes.operation = basepriv->attrib.operation;
 		break;
+	case DASD_ECKD_CCW_READ_TRACK:
 	case DASD_ECKD_CCW_READ_TRACK_DATA:
 		dedata->mask.perm = 0x1;
 		dedata->attributes.operation = basepriv->attrib.operation;
···
 		dedata->mask.auth = 0x1;
 		dedata->attributes.operation = DASD_BYPASS_CACHE;
 		rc = check_XRC_on_prefix(pfxdata, basedev);
+		break;
+	case DASD_ECKD_CCW_WRITE_FULL_TRACK:
+		dedata->mask.perm = 0x03;
+		dedata->attributes.operation = basepriv->attrib.operation;
+		dedata->blk_size = 0;
 		break;
 	case DASD_ECKD_CCW_WRITE_TRACK_DATA:
 		dedata->mask.perm = 0x02;
···
 		dasd_sfree_request(init_cqr, device);
 	}
 
+	if (device->features & DASD_FEATURE_USERAW) {
+		block->bp_block = DASD_RAW_BLOCKSIZE;
+		blk_per_trk = DASD_RAW_BLOCK_PER_TRACK;
+		block->s2b_shift = 3;
+		goto raw;
+	}
+
 	if (status == INIT_CQR_UNFORMATTED) {
 		dev_warn(&device->cdev->dev, "The DASD is not formatted\n");
 		return -EMEDIUMTYPE;
···
 			dev_warn(&device->cdev->dev,
 				 "Track 0 has no records following the VTOC\n");
 	}
+
 	if (count_area != NULL && count_area->kl == 0) {
 		/* we found notthing violating our disk layout */
 		if (dasd_check_blocksize(count_area->dl) == 0)
···
 		block->s2b_shift++;
 
 	blk_per_trk = recs_per_track(&private->rdc_data, 0, block->bp_block);
+
+raw:
 	block->blocks = (private->real_cyl *
 			  private->rdc_data.trk_per_cyl *
 			  blk_per_trk);
···
 	return cqr;
 }
 
+static struct dasd_ccw_req *dasd_raw_build_cp(struct dasd_device *startdev,
+					       struct dasd_block *block,
+					       struct request *req)
+{
+	struct dasd_eckd_private *private;
+	unsigned long *idaws;
+	struct dasd_device *basedev;
+	struct dasd_ccw_req *cqr;
+	struct ccw1 *ccw;
+	struct req_iterator iter;
+	struct bio_vec *bv;
+	char *dst;
+	unsigned char cmd;
+	unsigned int trkcount;
+	unsigned int seg_len, len_to_track_end;
+	unsigned int first_offs;
+	unsigned int cidaw, cplength, datasize;
+	sector_t first_trk, last_trk;
+	unsigned int pfx_datasize;
+
+	/*
+	 * raw track access needs to be mutiple of 64k and on 64k boundary
+	 */
+	if ((blk_rq_pos(req) % DASD_RAW_SECTORS_PER_TRACK) != 0) {
+		cqr = ERR_PTR(-EINVAL);
+		goto out;
+	}
+	if (((blk_rq_pos(req) + blk_rq_sectors(req)) %
+	     DASD_RAW_SECTORS_PER_TRACK) != 0) {
+		cqr = ERR_PTR(-EINVAL);
+		goto out;
+	}
+
+	first_trk = blk_rq_pos(req) / DASD_RAW_SECTORS_PER_TRACK;
+	last_trk = (blk_rq_pos(req) + blk_rq_sectors(req) - 1) /
+		DASD_RAW_SECTORS_PER_TRACK;
+	trkcount = last_trk - first_trk + 1;
+	first_offs = 0;
+	basedev = block->base;
+	private = (struct dasd_eckd_private *) basedev->private;
+
+	if (rq_data_dir(req) == READ)
+		cmd = DASD_ECKD_CCW_READ_TRACK;
+	else if (rq_data_dir(req) == WRITE)
+		cmd = DASD_ECKD_CCW_WRITE_FULL_TRACK;
+	else {
+		cqr = ERR_PTR(-EINVAL);
+		goto out;
+	}
+
+	/*
+	 * Raw track based I/O needs IDAWs for each page,
+	 * and not just for 64 bit addresses.
+	 */
+	cidaw = trkcount * DASD_RAW_BLOCK_PER_TRACK;
+
+	/* 1x prefix + one read/write ccw per track */
+	cplength = 1 + trkcount;
+
+	/*
+	 * struct PFX_eckd_data has up to 2 byte as extended parameter
+	 * this is needed for write full track and has to be mentioned
+	 * seperately
+	 * add 8 instead of 2 to keep 8 byte boundary
+	 */
+	pfx_datasize = sizeof(struct PFX_eckd_data) + 8;
+
+	datasize = pfx_datasize + cidaw * sizeof(unsigned long long);
+
+	/* Allocate the ccw request. */
+	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, cplength,
+				   datasize, startdev);
+	if (IS_ERR(cqr))
+		goto out;
+	ccw = cqr->cpaddr;
+
+	if (prefix_LRE(ccw++, cqr->data, first_trk, last_trk, cmd,
+		       basedev, startdev, 1 /* format */, first_offs + 1,
+		       trkcount, 0, 0) == -EAGAIN) {
+		/* Clock not in sync and XRC is enabled.
+		 * Try again later.
+		 */
+		dasd_sfree_request(cqr, startdev);
+		cqr = ERR_PTR(-EAGAIN);
+		goto out;
+	}
+
+	idaws = (unsigned long *)(cqr->data + pfx_datasize);
+
+	len_to_track_end = 0;
+
+	rq_for_each_segment(bv, req, iter) {
+		dst = page_address(bv->bv_page) + bv->bv_offset;
+		seg_len = bv->bv_len;
+		if (!len_to_track_end) {
+			ccw[-1].flags |= CCW_FLAG_CC;
+			ccw->cmd_code = cmd;
+			/* maximum 3390 track size */
+			ccw->count = 57326;
+			/* 64k map to one track */
+			len_to_track_end = 65536;
+			ccw->cda = (__u32)(addr_t)idaws;
+			ccw->flags |= CCW_FLAG_IDA;
+			ccw->flags |= CCW_FLAG_SLI;
+			ccw++;
+		}
+		len_to_track_end -= seg_len;
+		idaws = idal_create_words(idaws, dst, seg_len);
+	}
+
+	if (blk_noretry_request(req) ||
+	    block->base->features & DASD_FEATURE_FAILFAST)
+		set_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags);
+	cqr->startdev = startdev;
+	cqr->memdev = startdev;
+	cqr->block = block;
+	cqr->expires = startdev->default_expires * HZ;
+	cqr->lpm = startdev->path_data.ppm;
+	cqr->retries = 256;
+	cqr->buildclk = get_clock();
+	cqr->status = DASD_CQR_FILLED;
+
+	if (IS_ERR(cqr) && PTR_ERR(cqr) != -EAGAIN)
+		cqr = NULL;
+out:
+	return cqr;
+}
+
+
 static int
 dasd_eckd_free_cp(struct dasd_ccw_req *cqr, struct request *req)
 {
···
 
 	spin_lock_irqsave(get_ccwdev_lock(startdev->cdev), flags);
 	private->count++;
-	cqr = dasd_eckd_build_cp(startdev, block, req);
+	if ((base->features & DASD_FEATURE_USERAW))
+		cqr = dasd_raw_build_cp(startdev, block, req);
+	else
+		cqr = dasd_eckd_build_cp(startdev, block, req);
 	if (IS_ERR(cqr))
 		private->count--;
 	spin_unlock_irqrestore(get_ccwdev_lock(startdev->cdev), flags);

drivers/s390/block/dasd_eckd.h

···
 #define DASD_ECKD_CCW_WRITE_KD_MT	 0x8d
 #define DASD_ECKD_CCW_READ_KD_MT	 0x8e
 #define DASD_ECKD_CCW_RELEASE		 0x94
+#define DASD_ECKD_CCW_WRITE_FULL_TRACK	 0x95
 #define DASD_ECKD_CCW_READ_CKD_MT	 0x9e
 #define DASD_ECKD_CCW_WRITE_CKD_MT	 0x9d
 #define DASD_ECKD_CCW_WRITE_TRACK_DATA	 0xA5
 #define DASD_ECKD_CCW_READ_TRACK_DATA	 0xA6
 #define DASD_ECKD_CCW_RESERVE		 0xB4
+#define DASD_ECKD_CCW_READ_TRACK	 0xDE
 #define DASD_ECKD_CCW_PFX		 0xE7
 #define DASD_ECKD_CCW_PFX_READ		 0xEA
 #define DASD_ECKD_CCW_RSCK		 0xF9