snic: driver for Cisco SCSI HBA

Cisco has developed a new PCI HBA interface called sNIC, which stands for
SCSI NIC. This is a new storage feature supported on specialized network
adapter. The new PCI function provides a uniform host interface and abstracts
backend storage.

[jejb: fix up checkpatch errors]
Signed-off-by: Narsimhulu Musini <nmusini@cisco.com>
Signed-off-by: Sesidhar Baddela <sebaddel@cisco.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>

1 files changed, 1044 insertions, 0 deletions

diff --git a/drivers/scsi/snic/snic_main.c b/drivers/scsi/snic/snic_main.c
new file mode 100644
index 000000000000..b2b87cef00fc
--- /dev/null
+++ b/drivers/scsi/snic/snic_main.c
@@ -0,0 +1,1044 @@
+/*
+ * Copyright 2014 Cisco Systems, Inc.  All rights reserved.
+ *
+ * This program is free software; you may 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.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <linux/module.h>
+#include <linux/mempool.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/skbuff.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_tcq.h>
+
+#include "snic.h"
+#include "snic_fwint.h"
+
+#define PCI_DEVICE_ID_CISCO_SNIC	0x0046
+
+/* Supported devices by snic module */
+static struct pci_device_id snic_id_table[] = {
+	{PCI_DEVICE(0x1137, PCI_DEVICE_ID_CISCO_SNIC) },
+	{ 0, }	/* end of table */
+};
+
+unsigned int snic_log_level = 0x0;
+module_param(snic_log_level, int, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(snic_log_level, "bitmask for snic logging levels");
+
+#ifdef CONFIG_SCSI_SNIC_DEBUG_FS
+unsigned int snic_trace_max_pages = 16;
+module_param(snic_trace_max_pages, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(snic_trace_max_pages,
+		"Total allocated memory pages for snic trace buffer");
+
+#endif
+unsigned int snic_max_qdepth = SNIC_DFLT_QUEUE_DEPTH;
+module_param(snic_max_qdepth, uint, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(snic_max_qdepth, "Queue depth to report for each LUN");
+
+/*
+ * snic_slave_alloc : callback function to SCSI Mid Layer, called on
+ * scsi device initialization.
+ */
+static int
+snic_slave_alloc(struct scsi_device *sdev)
+{
+	struct snic_tgt *tgt = starget_to_tgt(scsi_target(sdev));
+
+	if (!tgt || snic_tgt_chkready(tgt))
+		return -ENXIO;
+
+	return 0;
+}
+
+/*
+ * snic_slave_configure : callback function to SCSI Mid Layer, called on
+ * scsi device initialization.
+ */
+static int
+snic_slave_configure(struct scsi_device *sdev)
+{
+	struct snic *snic = shost_priv(sdev->host);
+	u32 qdepth = 0, max_ios = 0;
+	int tmo = SNIC_DFLT_CMD_TIMEOUT * HZ;
+
+	/* Set Queue Depth */
+	max_ios = snic_max_qdepth;
+	qdepth = min_t(u32, max_ios, SNIC_MAX_QUEUE_DEPTH);
+	scsi_change_queue_depth(sdev, qdepth);
+
+	if (snic->fwinfo.io_tmo > 1)
+		tmo = snic->fwinfo.io_tmo * HZ;
+
+	/* FW requires extended timeouts */
+	blk_queue_rq_timeout(sdev->request_queue, tmo);
+
+	return 0;
+}
+
+static int
+snic_change_queue_depth(struct scsi_device *sdev, int qdepth)
+{
+	int qsz = 0;
+
+	qsz = min_t(u32, qdepth, SNIC_MAX_QUEUE_DEPTH);
+	scsi_change_queue_depth(sdev, qsz);
+	SNIC_INFO("QDepth Changed to %d\n", sdev->queue_depth);
+
+	return sdev->queue_depth;
+}
+
+static struct scsi_host_template snic_host_template = {
+	.module = THIS_MODULE,
+	.name = SNIC_DRV_NAME,
+	.queuecommand = snic_queuecommand,
+	.eh_abort_handler = snic_abort_cmd,
+	.eh_device_reset_handler = snic_device_reset,
+	.eh_host_reset_handler = snic_host_reset,
+	.slave_alloc = snic_slave_alloc,
+	.slave_configure = snic_slave_configure,
+	.change_queue_depth = snic_change_queue_depth,
+	.this_id = -1,
+	.cmd_per_lun = SNIC_DFLT_QUEUE_DEPTH,
+	.can_queue = SNIC_MAX_IO_REQ,
+	.use_clustering = ENABLE_CLUSTERING,
+	.sg_tablesize = SNIC_MAX_SG_DESC_CNT,
+	.max_sectors = 0x800,
+	.shost_attrs = snic_attrs,
+	.use_blk_tags = 1,
+	.track_queue_depth = 1,
+	.cmd_size = sizeof(struct snic_internal_io_state),
+	.proc_name = "snic_scsi",
+};
+
+/*
+ * snic_handle_link_event : Handles link events such as link up/down/error
+ */
+void
+snic_handle_link_event(struct snic *snic)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&snic->snic_lock, flags);
+	if (snic->stop_link_events) {
+		spin_unlock_irqrestore(&snic->snic_lock, flags);
+
+		return;
+	}
+	spin_unlock_irqrestore(&snic->snic_lock, flags);
+
+	queue_work(snic_glob->event_q, &snic->link_work);
+} /* end of snic_handle_link_event */
+
+/*
+ * snic_notify_set : sets notification area
+ * This notification area is to receive events from fw
+ * Note: snic supports only MSIX interrupts, in which we can just call
+ *  svnic_dev_notify_set directly
+ */
+static int
+snic_notify_set(struct snic *snic)
+{
+	int ret = 0;
+	enum vnic_dev_intr_mode intr_mode;
+
+	intr_mode = svnic_dev_get_intr_mode(snic->vdev);
+
+	if (intr_mode == VNIC_DEV_INTR_MODE_MSIX) {
+		ret = svnic_dev_notify_set(snic->vdev, SNIC_MSIX_ERR_NOTIFY);
+	} else {
+		SNIC_HOST_ERR(snic->shost,
+			      "Interrupt mode should be setup before devcmd notify set %d\n",
+			      intr_mode);
+		ret = -1;
+	}
+
+	return ret;
+} /* end of snic_notify_set */
+
+/*
+ * snic_dev_wait : polls vnic open status.
+ */
+static int
+snic_dev_wait(struct vnic_dev *vdev,
+		int (*start)(struct vnic_dev *, int),
+		int (*finished)(struct vnic_dev *, int *),
+		int arg)
+{
+	unsigned long time;
+	int ret, done;
+	int retry_cnt = 0;
+
+	ret = start(vdev, arg);
+	if (ret)
+		return ret;
+
+	/*
+	 * Wait for func to complete...2 seconds max.
+	 *
+	 * Sometimes schedule_timeout_uninterruptible take long	time
+	 * to wakeup, which results skipping retry. The retry counter
+	 * ensures to retry at least two times.
+	 */
+	time = jiffies + (HZ * 2);
+	do {
+		ret = finished(vdev, &done);
+		if (ret)
+			return ret;
+
+		if (done)
+			return 0;
+		schedule_timeout_uninterruptible(HZ/10);
+		++retry_cnt;
+	} while (time_after(time, jiffies) || (retry_cnt < 3));
+
+	return -ETIMEDOUT;
+} /* end of snic_dev_wait */
+
+/*
+ * snic_cleanup: called by snic_remove
+ * Stops the snic device, masks all interrupts, Completed CQ entries are
+ * drained. Posted WQ/RQ/Copy-WQ entries are cleanup
+ */
+static int
+snic_cleanup(struct snic *snic)
+{
+	unsigned int i;
+	int ret;
+
+	svnic_dev_disable(snic->vdev);
+	for (i = 0; i < snic->intr_count; i++)
+		svnic_intr_mask(&snic->intr[i]);
+
+	for (i = 0; i < snic->wq_count; i++) {
+		ret = svnic_wq_disable(&snic->wq[i]);
+		if (ret)
+			return ret;
+	}
+
+	/* Clean up completed IOs */
+	snic_fwcq_cmpl_handler(snic, -1);
+
+	snic_wq_cmpl_handler(snic, -1);
+
+	/* Clean up the IOs that have not completed */
+	for (i = 0; i < snic->wq_count; i++)
+		svnic_wq_clean(&snic->wq[i], snic_free_wq_buf);
+
+	for (i = 0; i < snic->cq_count; i++)
+		svnic_cq_clean(&snic->cq[i]);
+
+	for (i = 0; i < snic->intr_count; i++)
+		svnic_intr_clean(&snic->intr[i]);
+
+	/* Cleanup snic specific requests */
+	snic_free_all_untagged_reqs(snic);
+
+	/* Cleanup Pending SCSI commands */
+	snic_shutdown_scsi_cleanup(snic);
+
+	for (i = 0; i < SNIC_REQ_MAX_CACHES; i++)
+		mempool_destroy(snic->req_pool[i]);
+
+	return 0;
+} /* end of snic_cleanup */
+
+
+static void
+snic_iounmap(struct snic *snic)
+{
+	if (snic->bar0.vaddr)
+		iounmap(snic->bar0.vaddr);
+}
+
+/*
+ * snic_vdev_open_done : polls for svnic_dev_open cmd completion.
+ */
+static int
+snic_vdev_open_done(struct vnic_dev *vdev, int *done)
+{
+	struct snic *snic = svnic_dev_priv(vdev);
+	int ret;
+	int nretries = 5;
+
+	do {
+		ret = svnic_dev_open_done(vdev, done);
+		if (ret == 0)
+			break;
+
+		SNIC_HOST_INFO(snic->shost, "VNIC_DEV_OPEN Timedout.\n");
+	} while (nretries--);
+
+	return ret;
+} /* end of snic_vdev_open_done */
+
+/*
+ * snic_add_host : registers scsi host with ML
+ */
+static int
+snic_add_host(struct Scsi_Host *shost, struct pci_dev *pdev)
+{
+	int ret = 0;
+
+	ret = scsi_add_host(shost, &pdev->dev);
+	if (ret) {
+		SNIC_HOST_ERR(shost,
+			      "snic: scsi_add_host failed. %d\n",
+			      ret);
+
+		return ret;
+	}
+
+	SNIC_BUG_ON(shost->work_q != NULL);
+	snprintf(shost->work_q_name, sizeof(shost->work_q_name), "scsi_wq_%d",
+		 shost->host_no);
+	shost->work_q = create_singlethread_workqueue(shost->work_q_name);
+	if (!shost->work_q) {
+		SNIC_HOST_ERR(shost, "Failed to Create ScsiHost wq.\n");
+
+		ret = -ENOMEM;
+	}
+
+	return ret;
+} /* end of snic_add_host */
+
+static void
+snic_del_host(struct Scsi_Host *shost)
+{
+	if (!shost->work_q)
+		return;
+
+	destroy_workqueue(shost->work_q);
+	shost->work_q = NULL;
+	scsi_remove_host(shost);
+}
+
+int
+snic_get_state(struct snic *snic)
+{
+	return atomic_read(&snic->state);
+}
+
+void
+snic_set_state(struct snic *snic, enum snic_state state)
+{
+	SNIC_HOST_INFO(snic->shost, "snic state change from %s to %s\n",
+		       snic_state_to_str(snic_get_state(snic)),
+		       snic_state_to_str(state));
+
+	atomic_set(&snic->state, state);
+}
+
+/*
+ * snic_probe : Initialize the snic interface.
+ */
+static int
+snic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
+{
+	struct Scsi_Host *shost;
+	struct snic *snic;
+	mempool_t *pool;
+	unsigned long flags;
+	u32 max_ios = 0;
+	int ret, i;
+
+	/* Device Information */
+	SNIC_INFO("snic device %4x:%4x:%4x:%4x: ",
+		  pdev->vendor, pdev->device, pdev->subsystem_vendor,
+		  pdev->subsystem_device);
+
+	SNIC_INFO("snic device bus %x: slot %x: fn %x\n",
+		  pdev->bus->number, PCI_SLOT(pdev->devfn),
+		  PCI_FUNC(pdev->devfn));
+
+	/*
+	 * Allocate SCSI Host and setup association between host, and snic
+	 */
+	shost = scsi_host_alloc(&snic_host_template, sizeof(struct snic));
+	if (!shost) {
+		SNIC_ERR("Unable to alloc scsi_host\n");
+		ret = -ENOMEM;
+
+		goto prob_end;
+	}
+	snic = shost_priv(shost);
+	snic->shost = shost;
+
+	snprintf(snic->name, sizeof(snic->name) - 1, "%s%d", SNIC_DRV_NAME,
+		 shost->host_no);
+
+	SNIC_HOST_INFO(shost,
+		       "snic%d = %p shost = %p device bus %x: slot %x: fn %x\n",
+		       shost->host_no, snic, shost, pdev->bus->number,
+		       PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
+#ifdef CONFIG_SCSI_SNIC_DEBUG_FS
+	/* Per snic debugfs init */
+	ret = snic_stats_debugfs_init(snic);
+	if (ret) {
+		SNIC_HOST_ERR(snic->shost,
+			      "Failed to initialize debugfs stats\n");
+		snic_stats_debugfs_remove(snic);
+	}
+#endif
+
+	/* Setup PCI Resources */
+	pci_set_drvdata(pdev, snic);
+	snic->pdev = pdev;
+
+	ret = pci_enable_device(pdev);
+	if (ret) {
+		SNIC_HOST_ERR(shost,
+			      "Cannot enable PCI Resources, aborting : %d\n",
+			      ret);
+
+		goto err_free_snic;
+	}
+
+	ret = pci_request_regions(pdev, SNIC_DRV_NAME);
+	if (ret) {
+		SNIC_HOST_ERR(shost,
+			      "Cannot obtain PCI Resources, aborting : %d\n",
+			      ret);
+
+		goto err_pci_disable;
+	}
+
+	pci_set_master(pdev);
+
+	/*
+	 * Query PCI Controller on system for DMA addressing
+	 * limitation for the device. Try 43-bit first, and
+	 * fail to 32-bit.
+	 */
+	ret = pci_set_dma_mask(pdev, DMA_BIT_MASK(43));
+	if (ret) {
+		ret = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
+		if (ret) {
+			SNIC_HOST_ERR(shost,
+				      "No Usable DMA Configuration, aborting %d\n",
+				      ret);
+
+			goto err_rel_regions;
+		}
+
+		ret = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32));
+		if (ret) {
+			SNIC_HOST_ERR(shost,
+				      "Unable to obtain 32-bit DMA for consistent allocations, aborting: %d\n",
+				      ret);
+
+			goto err_rel_regions;
+		}
+	} else {
+		ret = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(43));
+		if (ret) {
+			SNIC_HOST_ERR(shost,
+				      "Unable to obtain 43-bit DMA for consistent allocations. aborting: %d\n",
+				      ret);
+
+			goto err_rel_regions;
+		}
+	}
+
+
+	/* Map vNIC resources from BAR0 */
+	if (!(pci_resource_flags(pdev, 0) & IORESOURCE_MEM)) {
+		SNIC_HOST_ERR(shost, "BAR0 not memory mappable aborting.\n");
+
+		ret = -ENODEV;
+		goto err_rel_regions;
+	}
+
+	snic->bar0.vaddr = pci_iomap(pdev, 0, 0);
+	if (!snic->bar0.vaddr) {
+		SNIC_HOST_ERR(shost,
+			      "Cannot memory map BAR0 res hdr aborting.\n");
+
+		ret = -ENODEV;
+		goto err_rel_regions;
+	}
+
+	snic->bar0.bus_addr = pci_resource_start(pdev, 0);
+	snic->bar0.len = pci_resource_len(pdev, 0);
+	SNIC_BUG_ON(snic->bar0.bus_addr == 0);
+
+	/* Devcmd2 Resource Allocation and Initialization */
+	snic->vdev = svnic_dev_alloc_discover(NULL, snic, pdev, &snic->bar0, 1);
+	if (!snic->vdev) {
+		SNIC_HOST_ERR(shost, "vNIC Resource Discovery Failed.\n");
+
+		ret = -ENODEV;
+		goto err_iounmap;
+	}
+
+	ret = svnic_dev_cmd_init(snic->vdev, 0);
+	if (ret) {
+		SNIC_HOST_INFO(shost, "Devcmd2 Init Failed. err = %d\n", ret);
+
+		goto err_vnic_unreg;
+	}
+
+	ret = snic_dev_wait(snic->vdev, svnic_dev_open, snic_vdev_open_done, 0);
+	if (ret) {
+		SNIC_HOST_ERR(shost,
+			      "vNIC dev open failed, aborting. %d\n",
+			      ret);
+
+		goto err_vnic_unreg;
+	}
+
+	ret = svnic_dev_init(snic->vdev, 0);
+	if (ret) {
+		SNIC_HOST_ERR(shost,
+			      "vNIC dev init failed. aborting. %d\n",
+			      ret);
+
+		goto err_dev_close;
+	}
+
+	/* Get vNIC information */
+	ret = snic_get_vnic_config(snic);
+	if (ret) {
+		SNIC_HOST_ERR(shost,
+			      "Get vNIC configuration failed, aborting. %d\n",
+			      ret);
+
+		goto err_dev_close;
+	}
+
+	/* Configure Maximum Outstanding IO reqs */
+	max_ios = snic->config.io_throttle_count;
+	if (max_ios != SNIC_UCSM_DFLT_THROTTLE_CNT_BLD)
+		shost->can_queue = min_t(u32, SNIC_MAX_IO_REQ,
+					 max_t(u32, SNIC_MIN_IO_REQ, max_ios));
+
+	snic->max_tag_id = shost->can_queue;
+
+	ret = scsi_init_shared_tag_map(shost, snic->max_tag_id);
+	if (ret) {
+		SNIC_HOST_ERR(shost,
+			      "Unable to alloc shared tag map. %d\n",
+			      ret);
+
+		goto err_dev_close;
+	}
+
+	shost->max_lun = snic->config.luns_per_tgt;
+	shost->max_id = SNIC_MAX_TARGET;
+
+	shost->max_cmd_len = MAX_COMMAND_SIZE; /*defined in scsi_cmnd.h*/
+
+	snic_get_res_counts(snic);
+
+	/*
+	 * Assumption: Only MSIx is supported
+	 */
+	ret = snic_set_intr_mode(snic);
+	if (ret) {
+		SNIC_HOST_ERR(shost,
+			      "Failed to set intr mode aborting. %d\n",
+			      ret);
+
+		goto err_dev_close;
+	}
+
+	ret = snic_alloc_vnic_res(snic);
+	if (ret) {
+		SNIC_HOST_ERR(shost,
+			      "Failed to alloc vNIC resources aborting. %d\n",
+			      ret);
+
+		goto err_clear_intr;
+	}
+
+	/* Initialize specific lists */
+	INIT_LIST_HEAD(&snic->list);
+
+	/*
+	 * spl_cmd_list for maintaining snic specific cmds
+	 * such as EXCH_VER_REQ, REPORT_TARGETS etc
+	 */
+	INIT_LIST_HEAD(&snic->spl_cmd_list);
+	spin_lock_init(&snic->spl_cmd_lock);
+
+	/* initialize all snic locks */
+	spin_lock_init(&snic->snic_lock);
+
+	for (i = 0; i < SNIC_WQ_MAX; i++)
+		spin_lock_init(&snic->wq_lock[i]);
+
+	for (i = 0; i < SNIC_IO_LOCKS; i++)
+		spin_lock_init(&snic->io_req_lock[i]);
+
+	pool = mempool_create_slab_pool(2,
+				snic_glob->req_cache[SNIC_REQ_CACHE_DFLT_SGL]);
+	if (!pool) {
+		SNIC_HOST_ERR(shost, "dflt sgl pool creation failed\n");
+
+		goto err_free_res;
+	}
+
+	snic->req_pool[SNIC_REQ_CACHE_DFLT_SGL] = pool;
+
+	pool = mempool_create_slab_pool(2,
+				snic_glob->req_cache[SNIC_REQ_CACHE_MAX_SGL]);
+	if (!pool) {
+		SNIC_HOST_ERR(shost, "max sgl pool creation failed\n");
+
+		goto err_free_dflt_sgl_pool;
+	}
+
+	snic->req_pool[SNIC_REQ_CACHE_MAX_SGL] = pool;
+
+	pool = mempool_create_slab_pool(2,
+				snic_glob->req_cache[SNIC_REQ_TM_CACHE]);
+	if (!pool) {
+		SNIC_HOST_ERR(shost, "snic tmreq info pool creation failed.\n");
+
+		goto err_free_max_sgl_pool;
+	}
+
+	snic->req_pool[SNIC_REQ_TM_CACHE] = pool;
+
+	/* Initialize snic state */
+	atomic_set(&snic->state, SNIC_INIT);
+
+	atomic_set(&snic->ios_inflight, 0);
+
+	/* Setup notification buffer area */
+	ret = snic_notify_set(snic);
+	if (ret) {
+		SNIC_HOST_ERR(shost,
+			      "Failed to alloc notify buffer aborting. %d\n",
+			      ret);
+
+		goto err_free_tmreq_pool;
+	}
+
+	/*
+	 * Initialization done with PCI system, hardware, firmware.
+	 * Add shost to SCSI
+	 */
+	ret = snic_add_host(shost, pdev);
+	if (ret) {
+		SNIC_HOST_ERR(shost,
+			      "Adding scsi host Failed ... exiting. %d\n",
+			      ret);
+
+		goto err_notify_unset;
+	}
+
+	spin_lock_irqsave(&snic_glob->snic_list_lock, flags);
+	list_add_tail(&snic->list, &snic_glob->snic_list);
+	spin_unlock_irqrestore(&snic_glob->snic_list_lock, flags);
+
+	snic_disc_init(&snic->disc);
+	INIT_WORK(&snic->tgt_work, snic_handle_tgt_disc);
+	INIT_WORK(&snic->disc_work, snic_handle_disc);
+	INIT_WORK(&snic->link_work, snic_handle_link);
+
+	/* Enable all queues */
+	for (i = 0; i < snic->wq_count; i++)
+		svnic_wq_enable(&snic->wq[i]);
+
+	ret = svnic_dev_enable_wait(snic->vdev);
+	if (ret) {
+		SNIC_HOST_ERR(shost,
+			      "vNIC dev enable failed w/ error %d\n",
+			      ret);
+
+		goto err_vdev_enable;
+	}
+
+	ret = snic_request_intr(snic);
+	if (ret) {
+		SNIC_HOST_ERR(shost, "Unable to request irq. %d\n", ret);
+
+		goto err_req_intr;
+	}
+
+	for (i = 0; i < snic->intr_count; i++)
+		svnic_intr_unmask(&snic->intr[i]);
+
+	snic_set_state(snic, SNIC_ONLINE);
+
+	/* Get snic params */
+	ret = snic_get_conf(snic);
+	if (ret) {
+		SNIC_HOST_ERR(shost,
+			      "Failed to get snic io config from FW w err %d\n",
+			      ret);
+
+		goto err_get_conf;
+	}
+
+	ret = snic_disc_start(snic);
+	if (ret) {
+		SNIC_HOST_ERR(shost, "snic_probe:Discovery Failed w err = %d\n",
+			      ret);
+
+		goto err_get_conf;
+	}
+
+	SNIC_HOST_INFO(shost, "SNIC Device Probe Successful.\n");
+
+	return 0;
+
+err_get_conf:
+	snic_free_all_untagged_reqs(snic);
+
+	for (i = 0; i < snic->intr_count; i++)
+		svnic_intr_mask(&snic->intr[i]);
+
+	snic_free_intr(snic);
+
+err_req_intr:
+	svnic_dev_disable(snic->vdev);
+
+err_vdev_enable:
+	for (i = 0; i < snic->wq_count; i++) {
+		int rc = 0;
+
+		rc = svnic_wq_disable(&snic->wq[i]);
+		if (rc) {
+			SNIC_HOST_ERR(shost,
+				      "WQ Disable Failed w/ err = %d\n", rc);
+
+			 break;
+		}
+	}
+	snic_del_host(snic->shost);
+
+err_notify_unset:
+	svnic_dev_notify_unset(snic->vdev);
+
+err_free_tmreq_pool:
+	mempool_destroy(snic->req_pool[SNIC_REQ_TM_CACHE]);
+
+err_free_max_sgl_pool:
+	mempool_destroy(snic->req_pool[SNIC_REQ_CACHE_MAX_SGL]);
+
+err_free_dflt_sgl_pool:
+	mempool_destroy(snic->req_pool[SNIC_REQ_CACHE_DFLT_SGL]);
+
+err_free_res:
+	snic_free_vnic_res(snic);
+
+err_clear_intr:
+	snic_clear_intr_mode(snic);
+
+err_dev_close:
+	svnic_dev_close(snic->vdev);
+
+err_vnic_unreg:
+	svnic_dev_unregister(snic->vdev);
+
+err_iounmap:
+	snic_iounmap(snic);
+
+err_rel_regions:
+	pci_release_regions(pdev);
+
+err_pci_disable:
+	pci_disable_device(pdev);
+
+err_free_snic:
+#ifdef CONFIG_SCSI_SNIC_DEBUG_FS
+	snic_stats_debugfs_remove(snic);
+#endif
+	scsi_host_put(shost);
+	pci_set_drvdata(pdev, NULL);
+
+prob_end:
+	SNIC_INFO("sNIC device : bus %d: slot %d: fn %d Registration Failed.\n",
+		  pdev->bus->number, PCI_SLOT(pdev->devfn),
+		  PCI_FUNC(pdev->devfn));
+
+	return ret;
+} /* end of snic_probe */
+
+
+/*
+ * snic_remove : invoked on unbinding the interface to cleanup the
+ * resources allocated in snic_probe on initialization.
+ */
+static void
+snic_remove(struct pci_dev *pdev)
+{
+	struct snic *snic = pci_get_drvdata(pdev);
+	unsigned long flags;
+
+	if (!snic) {
+		SNIC_INFO("sNIC dev: bus %d slot %d fn %d snic inst is null.\n",
+			  pdev->bus->number, PCI_SLOT(pdev->devfn),
+			  PCI_FUNC(pdev->devfn));
+
+		return;
+	}
+
+	/*
+	 * Mark state so that the workqueue thread stops forwarding
+	 * received frames and link events. ISR and other threads
+	 * that can queue work items will also stop creating work
+	 * items on the snic workqueue
+	 */
+	snic_set_state(snic, SNIC_OFFLINE);
+	spin_lock_irqsave(&snic->snic_lock, flags);
+	snic->stop_link_events = 1;
+	spin_unlock_irqrestore(&snic->snic_lock, flags);
+
+	flush_workqueue(snic_glob->event_q);
+	snic_disc_term(snic);
+
+	spin_lock_irqsave(&snic->snic_lock, flags);
+	snic->in_remove = 1;
+	spin_unlock_irqrestore(&snic->snic_lock, flags);
+
+	/*
+	 * This stops the snic device, masks all interrupts, Completed
+	 * CQ entries are drained. Posted WQ/RQ/Copy-WQ entries are
+	 * cleanup
+	 */
+	snic_cleanup(snic);
+
+	spin_lock_irqsave(&snic_glob->snic_list_lock, flags);
+	list_del(&snic->list);
+	spin_unlock_irqrestore(&snic_glob->snic_list_lock, flags);
+
+	snic_tgt_del_all(snic);
+#ifdef CONFIG_SCSI_SNIC_DEBUG_FS
+	snic_stats_debugfs_remove(snic);
+#endif
+	snic_del_host(snic->shost);
+
+	svnic_dev_notify_unset(snic->vdev);
+	snic_free_intr(snic);
+	snic_free_vnic_res(snic);
+	snic_clear_intr_mode(snic);
+	svnic_dev_close(snic->vdev);
+	svnic_dev_unregister(snic->vdev);
+	snic_iounmap(snic);
+	pci_release_regions(pdev);
+	pci_disable_device(pdev);
+	pci_set_drvdata(pdev, NULL);
+
+	/* this frees Scsi_Host and snic memory (continuous chunk) */
+	scsi_host_put(snic->shost);
+} /* end of snic_remove */
+
+
+struct snic_global *snic_glob;
+
+/*
+ * snic_global_data_init: Initialize SNIC Global Data
+ * Notes: All the global lists, variables should be part of global data
+ * this helps in debugging.
+ */
+static int
+snic_global_data_init(void)
+{
+	int ret = 0;
+	struct kmem_cache *cachep;
+	ssize_t len = 0;
+
+	snic_glob = kzalloc(sizeof(*snic_glob), GFP_KERNEL);
+
+	if (!snic_glob) {
+		SNIC_ERR("Failed to allocate Global Context.\n");
+
+		ret = -ENOMEM;
+		goto gdi_end;
+	}
+
+#ifdef CONFIG_SCSI_SNIC_DEBUG_FS
+	/* Debugfs related Initialization */
+	/* Create debugfs entries for snic */
+	ret = snic_debugfs_init();
+	if (ret < 0) {
+		SNIC_ERR("Failed to create sysfs dir for tracing and stats.\n");
+		snic_debugfs_term();
+		/* continue even if it fails */
+	}
+
+	/* Trace related Initialization */
+	/* Allocate memory for trace buffer */
+	ret = snic_trc_init();
+	if (ret < 0) {
+		SNIC_ERR("Trace buffer init failed, SNIC tracing disabled\n");
+		snic_trc_free();
+		/* continue even if it fails */
+	}
+
+#endif
+	INIT_LIST_HEAD(&snic_glob->snic_list);
+	spin_lock_init(&snic_glob->snic_list_lock);
+
+	/* Create a cache for allocation of snic_host_req+default size ESGLs */
+	len = sizeof(struct snic_req_info);
+	len += sizeof(struct snic_host_req) + sizeof(struct snic_dflt_sgl);
+	cachep = kmem_cache_create("snic_req_dfltsgl", len, SNIC_SG_DESC_ALIGN,
+				   SLAB_HWCACHE_ALIGN, NULL);
+	if (!cachep) {
+		SNIC_ERR("Failed to create snic default sgl slab\n");
+		ret = -ENOMEM;
+
+		goto err_dflt_req_slab;
+	}
+	snic_glob->req_cache[SNIC_REQ_CACHE_DFLT_SGL] = cachep;
+
+	/* Create a cache for allocation of max size Extended SGLs */
+	len = sizeof(struct snic_req_info);
+	len += sizeof(struct snic_host_req) + sizeof(struct snic_max_sgl);
+	cachep = kmem_cache_create("snic_req_maxsgl", len, SNIC_SG_DESC_ALIGN,
+				   SLAB_HWCACHE_ALIGN, NULL);
+	if (!cachep) {
+		SNIC_ERR("Failed to create snic max sgl slab\n");
+		ret = -ENOMEM;
+
+		goto err_max_req_slab;
+	}
+	snic_glob->req_cache[SNIC_REQ_CACHE_MAX_SGL] = cachep;
+
+	len = sizeof(struct snic_host_req);
+	cachep = kmem_cache_create("snic_req_maxsgl", len, SNIC_SG_DESC_ALIGN,
+				   SLAB_HWCACHE_ALIGN, NULL);
+	if (!cachep) {
+		SNIC_ERR("Failed to create snic tm req slab\n");
+		ret = -ENOMEM;
+
+		goto err_tmreq_slab;
+	}
+	snic_glob->req_cache[SNIC_REQ_TM_CACHE] = cachep;
+
+	/* snic_event queue */
+	snic_glob->event_q = create_singlethread_workqueue("snic_event_wq");
+	if (!snic_glob->event_q) {
+		SNIC_ERR("snic event queue create failed\n");
+		ret = -ENOMEM;
+
+		goto err_eventq;
+	}
+
+	return ret;
+
+err_eventq:
+	kmem_cache_destroy(snic_glob->req_cache[SNIC_REQ_TM_CACHE]);
+
+err_tmreq_slab:
+	kmem_cache_destroy(snic_glob->req_cache[SNIC_REQ_CACHE_MAX_SGL]);
+
+err_max_req_slab:
+	kmem_cache_destroy(snic_glob->req_cache[SNIC_REQ_CACHE_DFLT_SGL]);
+
+err_dflt_req_slab:
+#ifdef CONFIG_SCSI_SNIC_DEBUG_FS
+	snic_trc_free();
+	snic_debugfs_term();
+#endif
+	kfree(snic_glob);
+	snic_glob = NULL;
+
+gdi_end:
+	return ret;
+} /* end of snic_glob_init */
+
+/*
+ * snic_global_data_cleanup : Frees SNIC Global Data
+ */
+static void
+snic_global_data_cleanup(void)
+{
+	SNIC_BUG_ON(snic_glob == NULL);
+
+	destroy_workqueue(snic_glob->event_q);
+	kmem_cache_destroy(snic_glob->req_cache[SNIC_REQ_TM_CACHE]);
+	kmem_cache_destroy(snic_glob->req_cache[SNIC_REQ_CACHE_MAX_SGL]);
+	kmem_cache_destroy(snic_glob->req_cache[SNIC_REQ_CACHE_DFLT_SGL]);
+
+#ifdef CONFIG_SCSI_SNIC_DEBUG_FS
+	/* Freeing Trace Resources */
+	snic_trc_free();
+
+	/* Freeing Debugfs Resources */
+	snic_debugfs_term();
+#endif
+	kfree(snic_glob);
+	snic_glob = NULL;
+} /* end of snic_glob_cleanup */
+
+static struct pci_driver snic_driver = {
+	.name = SNIC_DRV_NAME,
+	.id_table = snic_id_table,
+	.probe = snic_probe,
+	.remove = snic_remove,
+};
+
+static int __init
+snic_init_module(void)
+{
+	int ret = 0;
+
+#ifndef __x86_64__
+	SNIC_INFO("SNIC Driver is supported only for x86_64 platforms!\n");
+	add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
+#endif
+
+	SNIC_INFO("%s, ver %s\n", SNIC_DRV_DESCRIPTION, SNIC_DRV_VERSION);
+
+	ret = snic_global_data_init();
+	if (ret) {
+		SNIC_ERR("Failed to Initialize Global Data.\n");
+
+		return ret;
+	}
+
+	ret = pci_register_driver(&snic_driver);
+	if (ret < 0) {
+		SNIC_ERR("PCI driver register error\n");
+
+		goto err_pci_reg;
+	}
+
+	return ret;
+
+err_pci_reg:
+	snic_global_data_cleanup();
+
+	return ret;
+}
+
+static void __exit
+snic_cleanup_module(void)
+{
+	pci_unregister_driver(&snic_driver);
+	snic_global_data_cleanup();
+}
+
+module_init(snic_init_module);
+module_exit(snic_cleanup_module);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION(SNIC_DRV_DESCRIPTION);
+MODULE_VERSION(SNIC_DRV_VERSION);
+MODULE_DEVICE_TABLE(pci, snic_id_table);
+MODULE_AUTHOR("Narsimhulu Musini <nmusini@cisco.com>, "
+	      "Sesidhar Baddela <sebaddel@cisco.com>");