[linux.git] / include / scsi / scsi_tcq.h

#ifndef _SCSI_SCSI_TCQ_H
#define _SCSI_SCSI_TCQ_H

#include <linux/blkdev.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>

#define MSG_SIMPLE_TAG	0x20
#define MSG_HEAD_TAG	0x21
#define MSG_ORDERED_TAG	0x22
#define MSG_ACA_TAG	0x24	/* unsupported */

#define SCSI_NO_TAG	(-1)    /* identify no tag in use */


#ifdef CONFIG_BLOCK

/**
 * scsi_get_tag_type - get the type of tag the device supports
 * @sdev:	the scsi device
 *
 * Notes:
 *	If the drive only supports simple tags, returns MSG_SIMPLE_TAG
 *	if it supports all tag types, returns MSG_ORDERED_TAG.
 */
static inline int scsi_get_tag_type(struct scsi_device *sdev)
{
	if (!sdev->tagged_supported)
		return 0;
	if (sdev->ordered_tags)
		return MSG_ORDERED_TAG;
	if (sdev->simple_tags)
		return MSG_SIMPLE_TAG;
	return 0;
}

static inline void scsi_set_tag_type(struct scsi_device *sdev, int tag)
{
	switch (tag) {
	case MSG_ORDERED_TAG:
		sdev->ordered_tags = 1;
		/* fall through */
	case MSG_SIMPLE_TAG:
		sdev->simple_tags = 1;
		break;
	case 0:
		/* fall through */
	default:
		sdev->ordered_tags = 0;
		sdev->simple_tags = 0;
		break;
	}
}
/**
 * scsi_activate_tcq - turn on tag command queueing
 * @SDpnt:	device to turn on TCQ for
 * @depth:	queue depth
 *
 * Notes:
 *	Eventually, I hope depth would be the maximum depth
 *	the device could cope with and the real queue depth
 *	would be adjustable from 0 to depth.
 **/
static inline void scsi_activate_tcq(struct scsi_device *sdev, int depth)
{
	if (!sdev->tagged_supported)
		return;

	if (!blk_queue_tagged(sdev->request_queue))
		blk_queue_init_tags(sdev->request_queue, depth,
				    sdev->host->bqt);

	scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
}

/**
 * scsi_deactivate_tcq - turn off tag command queueing
 * @SDpnt:	device to turn off TCQ for
 **/
static inline void scsi_deactivate_tcq(struct scsi_device *sdev, int depth)
{
	if (blk_queue_tagged(sdev->request_queue))
		blk_queue_free_tags(sdev->request_queue);
	scsi_adjust_queue_depth(sdev, 0, depth);
}

/**
 * scsi_populate_tag_msg - place a tag message in a buffer
 * @SCpnt:	pointer to the Scsi_Cmnd for the tag
 * @msg:	pointer to the area to place the tag
 *
 * Notes:
 *	designed to create the correct type of tag message for the 
 *	particular request.  Returns the size of the tag message.
 *	May return 0 if TCQ is disabled for this device.
 **/
static inline int scsi_populate_tag_msg(struct scsi_cmnd *cmd, char *msg)
{
        struct request *req = cmd->request;

        if (blk_rq_tagged(req)) {
		*msg++ = MSG_SIMPLE_TAG;
        	*msg++ = req->tag;
        	return 2;
	}

	return 0;
}

/**
 * scsi_find_tag - find a tagged command by device
 * @SDpnt:	pointer to the ScSI device
 * @tag:	the tag number
 *
 * Notes:
 *	Only works with tags allocated by the generic blk layer.
 **/
static inline struct scsi_cmnd *scsi_find_tag(struct scsi_device *sdev, int tag)
{

        struct request *req;

        if (tag != SCSI_NO_TAG) {
        	req = blk_queue_find_tag(sdev->request_queue, tag);
	        return req ? (struct scsi_cmnd *)req->special : NULL;
	}

	/* single command, look in space */
	return sdev->current_cmnd;
}

/**
 * scsi_init_shared_tag_map - create a shared tag map
 * @shost:	the host to share the tag map among all devices
 * @depth:	the total depth of the map
 */
static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
{
	/*
	 * If the shared tag map isn't already initialized, do it now.
	 * This saves callers from having to check ->bqt when setting up
	 * devices on the shared host (for libata)
	 */
	if (!shost->bqt) {
		shost->bqt = blk_init_tags(depth);
		if (!shost->bqt)
			return -ENOMEM;
	}

	return 0;
}

/**
 * scsi_host_find_tag - find the tagged command by host
 * @shost:	pointer to scsi_host
 * @tag:	tag of the scsi_cmnd
 *
 * Notes:
 *	Only works with tags allocated by the generic blk layer.
 **/
static inline struct scsi_cmnd *scsi_host_find_tag(struct Scsi_Host *shost,
						int tag)
{
	struct request *req;

	if (tag != SCSI_NO_TAG) {
		req = blk_map_queue_find_tag(shost->bqt, tag);
		return req ? (struct scsi_cmnd *)req->special : NULL;
	}
	return NULL;
}

#endif /* CONFIG_BLOCK */
#endif /* _SCSI_SCSI_TCQ_H */
Commit	Line	Data
1da177e4 LT	1	#ifndef _SCSI_SCSI_TCQ_H
	2	#define _SCSI_SCSI_TCQ_H
	3
	4	#include <linux/blkdev.h>
	5	#include <scsi/scsi_cmnd.h>
	6	#include <scsi/scsi_device.h>
86e33a29	7	#include <scsi/scsi_host.h>
1da177e4	8
1da177e4 LT	9	#define MSG_SIMPLE_TAG 0x20
	10	#define MSG_HEAD_TAG 0x21
	11	#define MSG_ORDERED_TAG 0x22
e66ecd50	12	#define MSG_ACA_TAG 0x24 /* unsupported */
1da177e4 LT	13
	14	#define SCSI_NO_TAG (-1) /* identify no tag in use */
	15
	16
9361401e	17	#ifdef CONFIG_BLOCK
1da177e4 LT	18
	19	/**
	20	* scsi_get_tag_type - get the type of tag the device supports
	21	* @sdev: the scsi device
	22	*
	23	* Notes:
	24	* If the drive only supports simple tags, returns MSG_SIMPLE_TAG
	25	* if it supports all tag types, returns MSG_ORDERED_TAG.
	26	*/
	27	static inline int scsi_get_tag_type(struct scsi_device *sdev)
	28	{
	29	if (!sdev->tagged_supported)
	30	return 0;
	31	if (sdev->ordered_tags)
	32	return MSG_ORDERED_TAG;
	33	if (sdev->simple_tags)
	34	return MSG_SIMPLE_TAG;
	35	return 0;
	36	}
	37
	38	static inline void scsi_set_tag_type(struct scsi_device *sdev, int tag)
	39	{
	40	switch (tag) {
	41	case MSG_ORDERED_TAG:
	42	sdev->ordered_tags = 1;
	43	/* fall through */
	44	case MSG_SIMPLE_TAG:
	45	sdev->simple_tags = 1;
	46	break;
	47	case 0:
	48	/* fall through */
	49	default:
	50	sdev->ordered_tags = 0;
	51	sdev->simple_tags = 0;
	52	break;
	53	}
	54	}
	55	/**
	56	* scsi_activate_tcq - turn on tag command queueing
	57	* @SDpnt: device to turn on TCQ for
	58	* @depth: queue depth
	59	*
	60	* Notes:
	61	* Eventually, I hope depth would be the maximum depth
	62	* the device could cope with and the real queue depth
	63	* would be adjustable from 0 to depth.
	64	**/
	65	static inline void scsi_activate_tcq(struct scsi_device *sdev, int depth)
	66	{
	67	if (!sdev->tagged_supported)
	68	return;
	69
	70	if (!blk_queue_tagged(sdev->request_queue))
86e33a29 JB	71	blk_queue_init_tags(sdev->request_queue, depth,
86e33a29 JB	72	sdev->host->bqt);
1da177e4 LT	73
	74	scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
	75	}
	76
	77	/**
	78	* scsi_deactivate_tcq - turn off tag command queueing
	79	* @SDpnt: device to turn off TCQ for
	80	**/
	81	static inline void scsi_deactivate_tcq(struct scsi_device *sdev, int depth)
	82	{
	83	if (blk_queue_tagged(sdev->request_queue))
	84	blk_queue_free_tags(sdev->request_queue);
	85	scsi_adjust_queue_depth(sdev, 0, depth);
	86	}
	87
	88	/**
	89	* scsi_populate_tag_msg - place a tag message in a buffer
	90	* @SCpnt: pointer to the Scsi_Cmnd for the tag
	91	* @msg: pointer to the area to place the tag
	92	*
	93	* Notes:
	94	* designed to create the correct type of tag message for the
	95	* particular request. Returns the size of the tag message.
	96	* May return 0 if TCQ is disabled for this device.
	97	**/
	98	static inline int scsi_populate_tag_msg(struct scsi_cmnd cmd, char msg)
	99	{
	100	struct request *req = cmd->request;
1da177e4 LT	101
1da177e4 LT	102	if (blk_rq_tagged(req)) {
9cbbdca4	103	*msg++ = MSG_SIMPLE_TAG;
1da177e4 LT	104	*msg++ = req->tag;
	105	return 2;
	106	}
	107
	108	return 0;
	109	}
	110
	111	/**
	112	* scsi_find_tag - find a tagged command by device
	113	* @SDpnt: pointer to the ScSI device
	114	* @tag: the tag number
	115	*
	116	* Notes:
	117	* Only works with tags allocated by the generic blk layer.
	118	**/
	119	static inline struct scsi_cmnd scsi_find_tag(struct scsi_device sdev, int tag)
	120	{
	121
	122	struct request *req;
	123
	124	if (tag != SCSI_NO_TAG) {
	125	req = blk_queue_find_tag(sdev->request_queue, tag);
	126	return req ? (struct scsi_cmnd *)req->special : NULL;
	127	}
	128
	129	/* single command, look in space */
	130	return sdev->current_cmnd;
	131	}
	132
86e33a29 JB	133	/**
	134	* scsi_init_shared_tag_map - create a shared tag map
	135	* @shost: the host to share the tag map among all devices
	136	* @depth: the total depth of the map
	137	*/
deb81d80	138	static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
86e33a29	139	{
3070f69b JA	140	/*
	141	* If the shared tag map isn't already initialized, do it now.
	142	* This saves callers from having to check ->bqt when setting up
	143	* devices on the shared host (for libata)
	144	*/
	145	if (!shost->bqt) {
	146	shost->bqt = blk_init_tags(depth);
	147	if (!shost->bqt)
	148	return -ENOMEM;
	149	}
	150
	151	return 0;
86e33a29 JB	152	}
86e33a29 JB	153
f583f492 DS	154	/**
	155	* scsi_host_find_tag - find the tagged command by host
	156	* @shost: pointer to scsi_host
	157	* @tag: tag of the scsi_cmnd
	158	*
	159	* Notes:
	160	* Only works with tags allocated by the generic blk layer.
	161	**/
	162	static inline struct scsi_cmnd scsi_host_find_tag(struct Scsi_Host shost,
	163	int tag)
	164	{
	165	struct request *req;
	166
	167	if (tag != SCSI_NO_TAG) {
	168	req = blk_map_queue_find_tag(shost->bqt, tag);
	169	return req ? (struct scsi_cmnd *)req->special : NULL;
	170	}
	171	return NULL;
	172	}
	173
9361401e	174	#endif /* CONFIG_BLOCK */
1da177e4	175	#endif /* _SCSI_SCSI_TCQ_H */