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, 204 insertions, 0 deletions

diff --git a/drivers/scsi/snic/snic_isr.c b/drivers/scsi/snic/snic_isr.c
new file mode 100644
index 000000000000..a85fae25ec8c
--- /dev/null
+++ b/drivers/scsi/snic/snic_isr.c
@@ -0,0 +1,204 @@
+/*
+ * 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/string.h>
+#include <linux/errno.h>
+#include <linux/pci.h>
+#include <linux/interrupt.h>
+
+#include "vnic_dev.h"
+#include "vnic_intr.h"
+#include "vnic_stats.h"
+#include "snic_io.h"
+#include "snic.h"
+
+
+/*
+ * snic_isr_msix_wq : MSIx ISR for work queue.
+ */
+
+static irqreturn_t
+snic_isr_msix_wq(int irq, void *data)
+{
+	struct snic *snic = data;
+	unsigned long wq_work_done = 0;
+
+	snic->s_stats.misc.last_isr_time = jiffies;
+	atomic64_inc(&snic->s_stats.misc.isr_cnt);
+
+	wq_work_done = snic_wq_cmpl_handler(snic, -1);
+	svnic_intr_return_credits(&snic->intr[SNIC_MSIX_WQ],
+				  wq_work_done,
+				  1 /* unmask intr */,
+				  1 /* reset intr timer */);
+
+	return IRQ_HANDLED;
+} /* end of snic_isr_msix_wq */
+
+static irqreturn_t
+snic_isr_msix_io_cmpl(int irq, void *data)
+{
+	struct snic *snic = data;
+	unsigned long iocmpl_work_done = 0;
+
+	snic->s_stats.misc.last_isr_time = jiffies;
+	atomic64_inc(&snic->s_stats.misc.isr_cnt);
+
+	iocmpl_work_done = snic_fwcq_cmpl_handler(snic, -1);
+	svnic_intr_return_credits(&snic->intr[SNIC_MSIX_IO_CMPL],
+				  iocmpl_work_done,
+				  1 /* unmask intr */,
+				  1 /* reset intr timer */);
+
+	return IRQ_HANDLED;
+} /* end of snic_isr_msix_io_cmpl */
+
+static irqreturn_t
+snic_isr_msix_err_notify(int irq, void *data)
+{
+	struct snic *snic = data;
+
+	snic->s_stats.misc.last_isr_time = jiffies;
+	atomic64_inc(&snic->s_stats.misc.isr_cnt);
+
+	svnic_intr_return_all_credits(&snic->intr[SNIC_MSIX_ERR_NOTIFY]);
+	snic_log_q_error(snic);
+
+	/*Handling link events */
+	snic_handle_link_event(snic);
+
+	return IRQ_HANDLED;
+} /* end of snic_isr_msix_err_notify */
+
+
+void
+snic_free_intr(struct snic *snic)
+{
+	int i;
+
+	/* ONLY interrupt mode MSIX is supported */
+	for (i = 0; i < ARRAY_SIZE(snic->msix); i++) {
+		if (snic->msix[i].requested) {
+			free_irq(snic->msix_entry[i].vector,
+				 snic->msix[i].devid);
+		}
+	}
+} /* end of snic_free_intr */
+
+int
+snic_request_intr(struct snic *snic)
+{
+	int ret = 0, i;
+	enum vnic_dev_intr_mode intr_mode;
+
+	intr_mode = svnic_dev_get_intr_mode(snic->vdev);
+	SNIC_BUG_ON(intr_mode != VNIC_DEV_INTR_MODE_MSIX);
+
+	/*
+	 * Currently HW supports single WQ and CQ. So passing devid as snic.
+	 * When hardware supports multiple WQs and CQs, one idea is
+	 * to pass devid as corresponding WQ or CQ ptr and retrieve snic
+	 * from queue ptr.
+	 * Except for err_notify, which is always one.
+	 */
+	sprintf(snic->msix[SNIC_MSIX_WQ].devname,
+		"%.11s-scsi-wq",
+		snic->name);
+	snic->msix[SNIC_MSIX_WQ].isr = snic_isr_msix_wq;
+	snic->msix[SNIC_MSIX_WQ].devid = snic;
+
+	sprintf(snic->msix[SNIC_MSIX_IO_CMPL].devname,
+		"%.11s-io-cmpl",
+		snic->name);
+	snic->msix[SNIC_MSIX_IO_CMPL].isr = snic_isr_msix_io_cmpl;
+	snic->msix[SNIC_MSIX_IO_CMPL].devid = snic;
+
+	sprintf(snic->msix[SNIC_MSIX_ERR_NOTIFY].devname,
+		"%.11s-err-notify",
+		snic->name);
+	snic->msix[SNIC_MSIX_ERR_NOTIFY].isr = snic_isr_msix_err_notify;
+	snic->msix[SNIC_MSIX_ERR_NOTIFY].devid = snic;
+
+	for (i = 0; i < ARRAY_SIZE(snic->msix); i++) {
+		ret = request_irq(snic->msix_entry[i].vector,
+				  snic->msix[i].isr,
+				  0,
+				  snic->msix[i].devname,
+				  snic->msix[i].devid);
+		if (ret) {
+			SNIC_HOST_ERR(snic->shost,
+				      "MSI-X: requrest_irq(%d) failed %d\n",
+				      i,
+				      ret);
+			snic_free_intr(snic);
+			break;
+		}
+		snic->msix[i].requested = 1;
+	}
+
+	return ret;
+} /* end of snic_requrest_intr */
+
+int
+snic_set_intr_mode(struct snic *snic)
+{
+	unsigned int n = ARRAY_SIZE(snic->wq);
+	unsigned int m = SNIC_CQ_IO_CMPL_MAX;
+	unsigned int i;
+
+	/*
+	 * We need n WQs, m CQs, and n+m+1 INTRs
+	 * (last INTR is used for WQ/CQ errors and notification area
+	 */
+
+	BUILD_BUG_ON((ARRAY_SIZE(snic->wq) + SNIC_CQ_IO_CMPL_MAX) >
+			ARRAY_SIZE(snic->intr));
+	SNIC_BUG_ON(ARRAY_SIZE(snic->msix_entry) < (n + m + 1));
+
+	for (i = 0; i < (n + m + 1); i++)
+		snic->msix_entry[i].entry = i;
+
+	if (snic->wq_count >= n && snic->cq_count >= (n + m)) {
+		if (!pci_enable_msix(snic->pdev,
+				     snic->msix_entry,
+				     (n + m + 1))) {
+			snic->wq_count = n;
+			snic->cq_count = n + m;
+			snic->intr_count = n + m + 1;
+			snic->err_intr_offset = SNIC_MSIX_ERR_NOTIFY;
+
+			SNIC_ISR_DBG(snic->shost,
+				     "Using MSI-X Interrupts\n");
+			svnic_dev_set_intr_mode(snic->vdev,
+						VNIC_DEV_INTR_MODE_MSIX);
+
+			return 0;
+		}
+	}
+
+	svnic_dev_set_intr_mode(snic->vdev, VNIC_DEV_INTR_MODE_UNKNOWN);
+
+	return -EINVAL;
+} /* end of snic_set_intr_mode */
+
+void
+snic_clear_intr_mode(struct snic *snic)
+{
+	pci_disable_msix(snic->pdev);
+
+	svnic_dev_set_intr_mode(snic->vdev, VNIC_DEV_INTR_MODE_INTX);
+}