1 files changed, 261 insertions, 0 deletions
diff --git a/drivers/scsi/device_handler/scsi_dh_hp_sw.c b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
new file mode 100644
index 000000000..4a3f7831a
--- /dev/null
+++ b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
@@ -0,0 +1,261 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Basic HP/COMPAQ MSA 1000 support. This is only needed if your HW cannot be
+ * upgraded.
+ *
+ * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2006 Mike Christie
+ * Copyright (C) 2008 Hannes Reinecke <hare@suse.de>
+ */
+
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_dbg.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_dh.h>
+
+#define HP_SW_NAME			"hp_sw"
+
+#define HP_SW_TIMEOUT			(60 * HZ)
+#define HP_SW_RETRIES			3
+
+#define HP_SW_PATH_UNINITIALIZED	-1
+#define HP_SW_PATH_ACTIVE		0
+#define HP_SW_PATH_PASSIVE		1
+
+struct hp_sw_dh_data {
+	int path_state;
+	int retries;
+	int retry_cnt;
+	struct scsi_device *sdev;
+};
+
+static int hp_sw_start_stop(struct hp_sw_dh_data *);
+
+/*
+ * tur_done - Handle TEST UNIT READY return status
+ * @sdev: sdev the command has been sent to
+ * @errors: blk error code
+ *
+ * Returns SCSI_DH_DEV_OFFLINED if the sdev is on the passive path
+ */
+static int tur_done(struct scsi_device *sdev, struct hp_sw_dh_data *h,
+		    struct scsi_sense_hdr *sshdr)
+{
+	int ret = SCSI_DH_IO;
+
+	switch (sshdr->sense_key) {
+	case UNIT_ATTENTION:
+		ret = SCSI_DH_IMM_RETRY;
+		break;
+	case NOT_READY:
+		if (sshdr->asc == 0x04 && sshdr->ascq == 2) {
+			/*
+			 * LUN not ready - Initialization command required
+			 *
+			 * This is the passive path
+			 */
+			h->path_state = HP_SW_PATH_PASSIVE;
+			ret = SCSI_DH_OK;
+			break;
+		}
+		fallthrough;
+	default:
+		sdev_printk(KERN_WARNING, sdev,
+			   "%s: sending tur failed, sense %x/%x/%x\n",
+			   HP_SW_NAME, sshdr->sense_key, sshdr->asc,
+			   sshdr->ascq);
+		break;
+	}
+	return ret;
+}
+
+/*
+ * hp_sw_tur - Send TEST UNIT READY
+ * @sdev: sdev command should be sent to
+ *
+ * Use the TEST UNIT READY command to determine
+ * the path state.
+ */
+static int hp_sw_tur(struct scsi_device *sdev, struct hp_sw_dh_data *h)
+{
+	unsigned char cmd[6] = { TEST_UNIT_READY };
+	struct scsi_sense_hdr sshdr;
+	int ret = SCSI_DH_OK, res;
+	u64 req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
+		REQ_FAILFAST_DRIVER;
+
+retry:
+	res = scsi_execute(sdev, cmd, DMA_NONE, NULL, 0, NULL, &sshdr,
+			HP_SW_TIMEOUT, HP_SW_RETRIES, req_flags, 0, NULL);
+	if (res) {
+		if (scsi_sense_valid(&sshdr))
+			ret = tur_done(sdev, h, &sshdr);
+		else {
+			sdev_printk(KERN_WARNING, sdev,
+				    "%s: sending tur failed with %x\n",
+				    HP_SW_NAME, res);
+			ret = SCSI_DH_IO;
+		}
+	} else {
+		h->path_state = HP_SW_PATH_ACTIVE;
+		ret = SCSI_DH_OK;
+	}
+	if (ret == SCSI_DH_IMM_RETRY)
+		goto retry;
+
+	return ret;
+}
+
+/*
+ * hp_sw_start_stop - Send START STOP UNIT command
+ * @sdev: sdev command should be sent to
+ *
+ * Sending START STOP UNIT activates the SP.
+ */
+static int hp_sw_start_stop(struct hp_sw_dh_data *h)
+{
+	unsigned char cmd[6] = { START_STOP, 0, 0, 0, 1, 0 };
+	struct scsi_sense_hdr sshdr;
+	struct scsi_device *sdev = h->sdev;
+	int res, rc = SCSI_DH_OK;
+	int retry_cnt = HP_SW_RETRIES;
+	u64 req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
+		REQ_FAILFAST_DRIVER;
+
+retry:
+	res = scsi_execute(sdev, cmd, DMA_NONE, NULL, 0, NULL, &sshdr,
+			HP_SW_TIMEOUT, HP_SW_RETRIES, req_flags, 0, NULL);
+	if (res) {
+		if (!scsi_sense_valid(&sshdr)) {
+			sdev_printk(KERN_WARNING, sdev,
+				    "%s: sending start_stop_unit failed, "
+				    "no sense available\n", HP_SW_NAME);
+			return SCSI_DH_IO;
+		}
+		switch (sshdr.sense_key) {
+		case NOT_READY:
+			if (sshdr.asc == 0x04 && sshdr.ascq == 3) {
+				/*
+				 * LUN not ready - manual intervention required
+				 *
+				 * Switch-over in progress, retry.
+				 */
+				if (--retry_cnt)
+					goto retry;
+				rc = SCSI_DH_RETRY;
+				break;
+			}
+			fallthrough;
+		default:
+			sdev_printk(KERN_WARNING, sdev,
+				    "%s: sending start_stop_unit failed, "
+				    "sense %x/%x/%x\n", HP_SW_NAME,
+				    sshdr.sense_key, sshdr.asc, sshdr.ascq);
+			rc = SCSI_DH_IO;
+		}
+	}
+	return rc;
+}
+
+static blk_status_t hp_sw_prep_fn(struct scsi_device *sdev, struct request *req)
+{
+	struct hp_sw_dh_data *h = sdev->handler_data;
+
+	if (h->path_state != HP_SW_PATH_ACTIVE) {
+		req->rq_flags |= RQF_QUIET;
+		return BLK_STS_IOERR;
+	}
+
+	return BLK_STS_OK;
+}
+
+/*
+ * hp_sw_activate - Activate a path
+ * @sdev: sdev on the path to be activated
+ *
+ * The HP Active/Passive firmware is pretty simple;
+ * the passive path reports NOT READY with sense codes
+ * 0x04/0x02; a START STOP UNIT command will then
+ * activate the passive path (and deactivate the
+ * previously active one).
+ */
+static int hp_sw_activate(struct scsi_device *sdev,
+				activate_complete fn, void *data)
+{
+	int ret = SCSI_DH_OK;
+	struct hp_sw_dh_data *h = sdev->handler_data;
+
+	ret = hp_sw_tur(sdev, h);
+
+	if (ret == SCSI_DH_OK && h->path_state == HP_SW_PATH_PASSIVE)
+		ret = hp_sw_start_stop(h);
+
+	if (fn)
+		fn(data, ret);
+	return 0;
+}
+
+static int hp_sw_bus_attach(struct scsi_device *sdev)
+{
+	struct hp_sw_dh_data *h;
+	int ret;
+
+	h = kzalloc(sizeof(*h), GFP_KERNEL);
+	if (!h)
+		return SCSI_DH_NOMEM;
+	h->path_state = HP_SW_PATH_UNINITIALIZED;
+	h->retries = HP_SW_RETRIES;
+	h->sdev = sdev;
+
+	ret = hp_sw_tur(sdev, h);
+	if (ret != SCSI_DH_OK)
+		goto failed;
+	if (h->path_state == HP_SW_PATH_UNINITIALIZED) {
+		ret = SCSI_DH_NOSYS;
+		goto failed;
+	}
+
+	sdev_printk(KERN_INFO, sdev, "%s: attached to %s path\n",
+		    HP_SW_NAME, h->path_state == HP_SW_PATH_ACTIVE?
+		    "active":"passive");
+
+	sdev->handler_data = h;
+	return SCSI_DH_OK;
+failed:
+	kfree(h);
+	return ret;
+}
+
+static void hp_sw_bus_detach( struct scsi_device *sdev )
+{
+	kfree(sdev->handler_data);
+	sdev->handler_data = NULL;
+}
+
+static struct scsi_device_handler hp_sw_dh = {
+	.name		= HP_SW_NAME,
+	.module		= THIS_MODULE,
+	.attach		= hp_sw_bus_attach,
+	.detach		= hp_sw_bus_detach,
+	.activate	= hp_sw_activate,
+	.prep_fn	= hp_sw_prep_fn,
+};
+
+static int __init hp_sw_init(void)
+{
+	return scsi_register_device_handler(&hp_sw_dh);
+}
+
+static void __exit hp_sw_exit(void)
+{
+	scsi_unregister_device_handler(&hp_sw_dh);
+}
+
+module_init(hp_sw_init);
+module_exit(hp_sw_exit);
+
+MODULE_DESCRIPTION("HP Active/Passive driver");
+MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu");
+MODULE_LICENSE("GPL");