[SCSI] scsi_dh: add EMC Clariion device handler

This adds support for EMC Clariions. This patch has the features that
currently exists in mainline and advanced features from Ed's patches.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

3 files changed, 506 insertions, 0 deletions

diff --git a/drivers/scsi/device_handler/Kconfig b/drivers/scsi/device_handler/Kconfig
index 61578d84fa6e..2adc0f666b68 100644
--- a/drivers/scsi/device_handler/Kconfig
+++ b/drivers/scsi/device_handler/Kconfig
@@ -24,3 +24,9 @@ config SCSI_DH_HP_SW
         If you have a HP/COMPAQ MSA device that requires START_STOP to
         be sent to start it and cannot upgrade the firmware then select y.
         Otherwise, say N.
+
+config SCSI_DH_EMC
+        tristate "EMC CLARiiON Device Handler"
+        depends on SCSI_DH
+        help
+        If you have a EMC CLARiiON select y. Otherwise, say N.
diff --git a/drivers/scsi/device_handler/Makefile b/drivers/scsi/device_handler/Makefile
index 08ec1943f19e..35272e93b1c8 100644
--- a/drivers/scsi/device_handler/Makefile
+++ b/drivers/scsi/device_handler/Makefile
@@ -4,3 +4,4 @@
 obj-$(CONFIG_SCSI_DH)           += scsi_dh.o
 obj-$(CONFIG_SCSI_DH_RDAC)      += scsi_dh_rdac.o
 obj-$(CONFIG_SCSI_DH_HP_SW)     += scsi_dh_hp_sw.o
+obj-$(CONFIG_SCSI_DH_EMC)       += scsi_dh_emc.o
diff --git a/drivers/scsi/device_handler/scsi_dh_emc.c b/drivers/scsi/device_handler/scsi_dh_emc.c
new file mode 100644
index 000000000000..ed53f14007a2
--- /dev/null
+++ b/drivers/scsi/device_handler/scsi_dh_emc.c
@@ -0,0 +1,499 @@
+/*
+ * Target driver for EMC CLARiiON AX/CX-series hardware.
+ * Based on code from Lars Marowsky-Bree <lmb@suse.de>
+ * and Ed Goggin <egoggin@emc.com>.
+ *
+ * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2006 Mike Christie
+ *
+ * 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; either version 2, or (at your option)
+ * any later version.
+ *
+ * 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; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include <scsi/scsi.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_dh.h>
+#include <scsi/scsi_device.h>
+
+#define CLARIION_NAME                   "emc_clariion"
+
+#define CLARIION_TRESPASS_PAGE          0x22
+#define CLARIION_BUFFER_SIZE            0x80
+#define CLARIION_TIMEOUT                (60 * HZ)
+#define CLARIION_RETRIES                3
+#define CLARIION_UNBOUND_LU             -1
+
+static unsigned char long_trespass[] = {
+        0, 0, 0, 0,
+        CLARIION_TRESPASS_PAGE, /* Page code */
+        0x09,                   /* Page length - 2 */
+        0x81,                   /* Trespass code + Honor reservation bit */
+        0xff, 0xff,             /* Trespass target */
+        0, 0, 0, 0, 0, 0        /* Reserved bytes / unknown */
+};
+
+static unsigned char long_trespass_hr[] = {
+        0, 0, 0, 0,
+        CLARIION_TRESPASS_PAGE, /* Page code */
+        0x09,                   /* Page length - 2 */
+        0x01,                   /* Trespass code + Honor reservation bit */
+        0xff, 0xff,             /* Trespass target */
+        0, 0, 0, 0, 0, 0        /* Reserved bytes / unknown */
+};
+
+static unsigned char short_trespass[] = {
+        0, 0, 0, 0,
+        CLARIION_TRESPASS_PAGE, /* Page code */
+        0x02,                   /* Page length - 2 */
+        0x81,                   /* Trespass code + Honor reservation bit */
+        0xff,                   /* Trespass target */
+};
+
+static unsigned char short_trespass_hr[] = {
+        0, 0, 0, 0,
+        CLARIION_TRESPASS_PAGE, /* Page code */
+        0x02,                   /* Page length - 2 */
+        0x01,                   /* Trespass code + Honor reservation bit */
+        0xff,                   /* Trespass target */
+};
+
+struct clariion_dh_data {
+        /*
+         * Use short trespass command (FC-series) or the long version
+         * (default for AX/CX CLARiiON arrays).
+         */
+        unsigned short_trespass;
+        /*
+         * Whether or not (default) to honor SCSI reservations when
+         * initiating a switch-over.
+         */
+        unsigned hr;
+        /* I/O buffer for both MODE_SELECT and INQUIRY commands. */
+        char buffer[CLARIION_BUFFER_SIZE];
+        /*
+         * SCSI sense buffer for commands -- assumes serial issuance
+         * and completion sequence of all commands for same multipath.
+         */
+        unsigned char sense[SCSI_SENSE_BUFFERSIZE];
+        /* which SP (A=0,B=1,UNBOUND=-1) is dflt SP for path's mapped dev */
+        int default_sp;
+        /* which SP (A=0,B=1,UNBOUND=-1) is active for path's mapped dev */
+        int current_sp;
+};
+
+static inline struct clariion_dh_data
+                        *get_clariion_data(struct scsi_device *sdev)
+{
+        struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
+        BUG_ON(scsi_dh_data == NULL);
+        return ((struct clariion_dh_data *) scsi_dh_data->buf);
+}
+
+/*
+ * Parse MODE_SELECT cmd reply.
+ */
+static int trespass_endio(struct scsi_device *sdev, int result)
+{
+        int err = SCSI_DH_OK;
+        struct scsi_sense_hdr sshdr;
+        struct clariion_dh_data *csdev = get_clariion_data(sdev);
+        char *sense = csdev->sense;
+
+        if (status_byte(result) == CHECK_CONDITION &&
+            scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)) {
+                sdev_printk(KERN_ERR, sdev, "Found valid sense data 0x%2x, "
+                            "0x%2x, 0x%2x while sending CLARiiON trespass "
+                            "command.\n", sshdr.sense_key, sshdr.asc,
+                             sshdr.ascq);
+
+                if ((sshdr.sense_key == 0x05) && (sshdr.asc == 0x04) &&
+                     (sshdr.ascq == 0x00)) {
+                        /*
+                         * Array based copy in progress -- do not send
+                         * mode_select or copy will be aborted mid-stream.
+                         */
+                        sdev_printk(KERN_INFO, sdev, "Array Based Copy in "
+                                    "progress while sending CLARiiON trespass "
+                                    "command.\n");
+                        err = SCSI_DH_DEV_TEMP_BUSY;
+                } else if ((sshdr.sense_key == 0x02) && (sshdr.asc == 0x04) &&
+                            (sshdr.ascq == 0x03)) {
+                        /*
+                         * LUN Not Ready - Manual Intervention Required
+                         * indicates in-progress ucode upgrade (NDU).
+                         */
+                        sdev_printk(KERN_INFO, sdev, "Detected in-progress "
+                                    "ucode upgrade NDU operation while sending "
+                                    "CLARiiON trespass command.\n");
+                        err = SCSI_DH_DEV_TEMP_BUSY;
+                } else
+                        err = SCSI_DH_DEV_FAILED;
+        } else if (result) {
+                sdev_printk(KERN_ERR, sdev, "Error 0x%x while sending "
+                            "CLARiiON trespass command.\n", result);
+                err = SCSI_DH_IO;
+        }
+
+        return err;
+}
+
+static int parse_sp_info_reply(struct scsi_device *sdev, int result,
+                int *default_sp, int *current_sp, int *new_current_sp)
+{
+        int err = SCSI_DH_OK;
+        struct clariion_dh_data *csdev = get_clariion_data(sdev);
+
+        if (result == 0) {
+                /* check for in-progress ucode upgrade (NDU) */
+                if (csdev->buffer[48] != 0) {
+                        sdev_printk(KERN_NOTICE, sdev, "Detected in-progress "
+                               "ucode upgrade NDU operation while finding "
+                               "current active SP.");
+                        err = SCSI_DH_DEV_TEMP_BUSY;
+                } else {
+                        *default_sp = csdev->buffer[5];
+
+                        if (csdev->buffer[4] == 2)
+                                /* SP for path is current */
+                                *current_sp = csdev->buffer[8];
+                        else {
+                                if (csdev->buffer[4] == 1)
+                                        /* SP for this path is NOT current */
+                                        if (csdev->buffer[8] == 0)
+                                                *current_sp = 1;
+                                        else
+                                                *current_sp = 0;
+                                else
+                                        /* unbound LU or LUNZ */
+                                        *current_sp = CLARIION_UNBOUND_LU;
+                        }
+                        *new_current_sp =  csdev->buffer[8];
+                }
+        } else {
+                struct scsi_sense_hdr sshdr;
+
+                err = SCSI_DH_IO;
+
+                if (scsi_normalize_sense(csdev->sense, SCSI_SENSE_BUFFERSIZE,
+                                                           &sshdr))
+                        sdev_printk(KERN_ERR, sdev, "Found valid sense data "
+                              "0x%2x, 0x%2x, 0x%2x while finding current "
+                              "active SP.", sshdr.sense_key, sshdr.asc,
+                              sshdr.ascq);
+                else
+                        sdev_printk(KERN_ERR, sdev, "Error 0x%x finding "
+                              "current active SP.", result);
+        }
+
+        return err;
+}
+
+static int sp_info_endio(struct scsi_device *sdev, int result,
+                                        int mode_select_sent, int *done)
+{
+        struct clariion_dh_data *csdev = get_clariion_data(sdev);
+        int err_flags, default_sp, current_sp, new_current_sp;
+
+        err_flags = parse_sp_info_reply(sdev, result, &default_sp,
+                                             &current_sp, &new_current_sp);
+
+        if (err_flags != SCSI_DH_OK)
+                goto done;
+
+        if (mode_select_sent) {
+                csdev->default_sp = default_sp;
+                csdev->current_sp = current_sp;
+        } else {
+                /*
+                 * Issue the actual module_selec request IFF either
+                 * (1) we do not know the identity of the current SP OR
+                 * (2) what we think we know is actually correct.
+                 */
+                if ((current_sp != CLARIION_UNBOUND_LU) &&
+                    (new_current_sp != current_sp)) {
+
+                        csdev->default_sp = default_sp;
+                        csdev->current_sp = current_sp;
+
+                        sdev_printk(KERN_INFO, sdev, "Ignoring path group "
+                               "switch-over command for CLARiiON SP%s since "
+                               " mapped device is already initialized.",
+                               current_sp ? "B" : "A");
+                        if (done)
+                                *done = 1; /* as good as doing it */
+                }
+        }
+done:
+        return err_flags;
+}
+
+/*
+* Get block request for REQ_BLOCK_PC command issued to path.  Currently
+* limited to MODE_SELECT (trespass) and INQUIRY (VPD page 0xC0) commands.
+*
+* Uses data and sense buffers in hardware handler context structure and
+* assumes serial servicing of commands, both issuance and completion.
+*/
+static struct request *get_req(struct scsi_device *sdev, int cmd)
+{
+        struct clariion_dh_data *csdev = get_clariion_data(sdev);
+        struct request *rq;
+        unsigned char *page22;
+        int len = 0;
+
+        rq = blk_get_request(sdev->request_queue,
+                        (cmd == MODE_SELECT) ? WRITE : READ, GFP_ATOMIC);
+        if (!rq) {
+                sdev_printk(KERN_INFO, sdev, "get_req: blk_get_request failed");
+                return NULL;
+        }
+
+        memset(&rq->cmd, 0, BLK_MAX_CDB);
+        rq->cmd[0] = cmd;
+        rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
+
+        switch (cmd) {
+        case MODE_SELECT:
+                if (csdev->short_trespass) {
+                        page22 = csdev->hr ? short_trespass_hr : short_trespass;
+                        len = sizeof(short_trespass);
+                } else {
+                        page22 = csdev->hr ? long_trespass_hr : long_trespass;
+                        len = sizeof(long_trespass);
+                }
+                /*
+                 * Can't DMA from kernel BSS -- must copy selected trespass
+                 * command mode page contents to context buffer which is
+                 * allocated by kmalloc.
+                 */
+                BUG_ON((len > CLARIION_BUFFER_SIZE));
+                memcpy(csdev->buffer, page22, len);
+                rq->cmd_flags |= REQ_RW;
+                rq->cmd[1] = 0x10;
+                break;
+        case INQUIRY:
+                rq->cmd[1] = 0x1;
+                rq->cmd[2] = 0xC0;
+                len = CLARIION_BUFFER_SIZE;
+                memset(csdev->buffer, 0, CLARIION_BUFFER_SIZE);
+                break;
+        default:
+                BUG_ON(1);
+                break;
+        }
+
+        rq->cmd[4] = len;
+        rq->cmd_type = REQ_TYPE_BLOCK_PC;
+        rq->cmd_flags |= REQ_FAILFAST;
+        rq->timeout = CLARIION_TIMEOUT;
+        rq->retries = CLARIION_RETRIES;
+
+        rq->sense = csdev->sense;
+        memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
+        rq->sense_len = 0;
+
+        if (blk_rq_map_kern(sdev->request_queue, rq, csdev->buffer,
+                                                        len, GFP_ATOMIC)) {
+                __blk_put_request(rq->q, rq);
+                return NULL;
+        }
+
+        return rq;
+}
+
+static int send_cmd(struct scsi_device *sdev, int cmd)
+{
+        struct request *rq = get_req(sdev, cmd);
+
+        if (!rq)
+                return SCSI_DH_RES_TEMP_UNAVAIL;
+
+        return blk_execute_rq(sdev->request_queue, NULL, rq, 1);
+}
+
+static int clariion_activate(struct scsi_device *sdev)
+{
+        int result, done = 0;
+
+        result = send_cmd(sdev, INQUIRY);
+        result = sp_info_endio(sdev, result, 0, &done);
+        if (result || done)
+                goto done;
+
+        result = send_cmd(sdev, MODE_SELECT);
+        result = trespass_endio(sdev, result);
+        if (result)
+                goto done;
+
+        result = send_cmd(sdev, INQUIRY);
+        result = sp_info_endio(sdev, result, 1, NULL);
+done:
+        return result;
+}
+
+static int clariion_check_sense(struct scsi_device *sdev,
+                                struct scsi_sense_hdr *sense_hdr)
+{
+        switch (sense_hdr->sense_key) {
+        case NOT_READY:
+                if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x03)
+                        /*
+                         * LUN Not Ready - Manual Intervention Required
+                         * indicates this is a passive path.
+                         *
+                         * FIXME: However, if this is seen and EVPD C0
+                         * indicates that this is due to a NDU in
+                         * progress, we should set FAIL_PATH too.
+                         * This indicates we might have to do a SCSI
+                         * inquiry in the end_io path. Ugh.
+                         *
+                         * Can return FAILED only when we want the error
+                         * recovery process to kick in.
+                         */
+                        return SUCCESS;
+                break;
+        case ILLEGAL_REQUEST:
+                if (sense_hdr->asc == 0x25 && sense_hdr->ascq == 0x01)
+                        /*
+                         * An array based copy is in progress. Do not
+                         * fail the path, do not bypass to another PG,
+                         * do not retry. Fail the IO immediately.
+                         * (Actually this is the same conclusion as in
+                         * the default handler, but lets make sure.)
+                         *
+                         * Can return FAILED only when we want the error
+                         * recovery process to kick in.
+                         */
+                        return SUCCESS;
+                break;
+        case UNIT_ATTENTION:
+                if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
+                        /*
+                         * Unit Attention Code. This is the first IO
+                         * to the new path, so just retry.
+                         */
+                        return NEEDS_RETRY;
+                break;
+        }
+
+        /* success just means we do not care what scsi-ml does */
+        return SUCCESS;
+}
+
+static const struct {
+        char *vendor;
+        char *model;
+} clariion_dev_list[] = {
+        {"DGC", "RAID"},
+        {"DGC", "DISK"},
+        {NULL, NULL},
+};
+
+static int clariion_bus_notify(struct notifier_block *, unsigned long, void *);
+
+static struct scsi_device_handler clariion_dh = {
+        .name           = CLARIION_NAME,
+        .module         = THIS_MODULE,
+        .nb.notifier_call = clariion_bus_notify,
+        .check_sense    = clariion_check_sense,
+        .activate       = clariion_activate,
+};
+
+/*
+ * TODO: need some interface so we can set trespass values
+ */
+static int clariion_bus_notify(struct notifier_block *nb,
+                                unsigned long action, void *data)
+{
+        struct device *dev = data;
+        struct scsi_device *sdev = to_scsi_device(dev);
+        struct scsi_dh_data *scsi_dh_data;
+        struct clariion_dh_data *h;
+        int i, found = 0;
+        unsigned long flags;
+
+        if (action == BUS_NOTIFY_ADD_DEVICE) {
+                for (i = 0; clariion_dev_list[i].vendor; i++) {
+                        if (!strncmp(sdev->vendor, clariion_dev_list[i].vendor,
+                                     strlen(clariion_dev_list[i].vendor)) &&
+                            !strncmp(sdev->model, clariion_dev_list[i].model,
+                                     strlen(clariion_dev_list[i].model))) {
+                                found = 1;
+                                break;
+                        }
+                }
+                if (!found)
+                        goto out;
+
+                scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
+                                + sizeof(*h) , GFP_KERNEL);
+                if (!scsi_dh_data) {
+                        sdev_printk(KERN_ERR, sdev, "Attach failed %s.\n",
+                                    CLARIION_NAME);
+                        goto out;
+                }
+
+                scsi_dh_data->scsi_dh = &clariion_dh;
+                h = (struct clariion_dh_data *) scsi_dh_data->buf;
+                h->default_sp = CLARIION_UNBOUND_LU;
+                h->current_sp = CLARIION_UNBOUND_LU;
+
+                spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
+                sdev->scsi_dh_data = scsi_dh_data;
+                spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
+
+                sdev_printk(KERN_NOTICE, sdev, "Attached %s.\n", CLARIION_NAME);
+                try_module_get(THIS_MODULE);
+
+        } else if (action == BUS_NOTIFY_DEL_DEVICE) {
+                if (sdev->scsi_dh_data == NULL ||
+                                sdev->scsi_dh_data->scsi_dh != &clariion_dh)
+                        goto out;
+
+                spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
+                scsi_dh_data = sdev->scsi_dh_data;
+                sdev->scsi_dh_data = NULL;
+                spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
+
+                sdev_printk(KERN_NOTICE, sdev, "Dettached %s.\n",
+                            CLARIION_NAME);
+
+                kfree(scsi_dh_data);
+                module_put(THIS_MODULE);
+        }
+
+out:
+        return 0;
+}
+
+static int __init clariion_init(void)
+{
+        int r;
+
+        r = scsi_register_device_handler(&clariion_dh);
+        if (r != 0)
+                printk(KERN_ERR "Failed to register scsi device handler.");
+        return r;
+}
+
+static void __exit clariion_exit(void)
+{
+        scsi_unregister_device_handler(&clariion_dh);
+}
+
+module_init(clariion_init);
+module_exit(clariion_exit);
+
+MODULE_DESCRIPTION("EMC CX/AX/FC-family driver");
+MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, Chandra Seetharaman <sekharan@us.ibm.com>");
+MODULE_LICENSE("GPL");