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, 170 insertions, 0 deletions

diff --git a/drivers/scsi/snic/vnic_wq.h b/drivers/scsi/snic/vnic_wq.h
new file mode 100644
index 000000000000..7cc031c7ceba
--- /dev/null
+++ b/drivers/scsi/snic/vnic_wq.h
@@ -0,0 +1,170 @@
+/*
+ * 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.
+ */
+
+#ifndef _VNIC_WQ_H_
+#define _VNIC_WQ_H_
+
+#include <linux/pci.h>
+#include "vnic_dev.h"
+#include "vnic_cq.h"
+
+/* Work queue control */
+struct vnic_wq_ctrl {
+	u64 ring_base;			/* 0x00 */
+	u32 ring_size;			/* 0x08 */
+	u32 pad0;
+	u32 posted_index;		/* 0x10 */
+	u32 pad1;
+	u32 cq_index;			/* 0x18 */
+	u32 pad2;
+	u32 enable;			/* 0x20 */
+	u32 pad3;
+	u32 running;			/* 0x28 */
+	u32 pad4;
+	u32 fetch_index;		/* 0x30 */
+	u32 pad5;
+	u32 dca_value;			/* 0x38 */
+	u32 pad6;
+	u32 error_interrupt_enable;	/* 0x40 */
+	u32 pad7;
+	u32 error_interrupt_offset;	/* 0x48 */
+	u32 pad8;
+	u32 error_status;		/* 0x50 */
+	u32 pad9;
+};
+
+struct vnic_wq_buf {
+	struct vnic_wq_buf *next;
+	dma_addr_t dma_addr;
+	void *os_buf;
+	unsigned int len;
+	unsigned int index;
+	int sop;
+	void *desc;
+};
+
+/* Break the vnic_wq_buf allocations into blocks of 64 entries */
+#define VNIC_WQ_BUF_MIN_BLK_ENTRIES 32
+#define VNIC_WQ_BUF_DFLT_BLK_ENTRIES 64
+#define VNIC_WQ_BUF_BLK_ENTRIES(entries) \
+	((unsigned int)(entries < VNIC_WQ_BUF_DFLT_BLK_ENTRIES) ? \
+		VNIC_WQ_BUF_MIN_BLK_ENTRIES : VNIC_WQ_BUF_DFLT_BLK_ENTRIES)
+#define VNIC_WQ_BUF_BLK_SZ \
+	(VNIC_WQ_BUF_DFLT_BLK_ENTRIES * sizeof(struct vnic_wq_buf))
+#define VNIC_WQ_BUF_BLKS_NEEDED(entries) \
+	DIV_ROUND_UP(entries, VNIC_WQ_BUF_DFLT_BLK_ENTRIES)
+#define VNIC_WQ_BUF_BLKS_NEEDED(entries) \
+	DIV_ROUND_UP(entries, VNIC_WQ_BUF_DFLT_BLK_ENTRIES)
+#define VNIC_WQ_BUF_BLKS_MAX VNIC_WQ_BUF_BLKS_NEEDED(4096)
+
+struct vnic_wq {
+	unsigned int index;
+	struct vnic_dev *vdev;
+	struct vnic_wq_ctrl __iomem *ctrl;	/* memory-mapped */
+	struct vnic_dev_ring ring;
+	struct vnic_wq_buf *bufs[VNIC_WQ_BUF_BLKS_MAX];
+	struct vnic_wq_buf *to_use;
+	struct vnic_wq_buf *to_clean;
+	unsigned int pkts_outstanding;
+};
+
+static inline unsigned int svnic_wq_desc_avail(struct vnic_wq *wq)
+{
+	/* how many does SW own? */
+	return wq->ring.desc_avail;
+}
+
+static inline unsigned int svnic_wq_desc_used(struct vnic_wq *wq)
+{
+	/* how many does HW own? */
+	return wq->ring.desc_count - wq->ring.desc_avail - 1;
+}
+
+static inline void *svnic_wq_next_desc(struct vnic_wq *wq)
+{
+	return wq->to_use->desc;
+}
+
+static inline void svnic_wq_post(struct vnic_wq *wq,
+	void *os_buf, dma_addr_t dma_addr,
+	unsigned int len, int sop, int eop)
+{
+	struct vnic_wq_buf *buf = wq->to_use;
+
+	buf->sop = sop;
+	buf->os_buf = eop ? os_buf : NULL;
+	buf->dma_addr = dma_addr;
+	buf->len = len;
+
+	buf = buf->next;
+	if (eop) {
+		/* Adding write memory barrier prevents compiler and/or CPU
+		 * reordering, thus avoiding descriptor posting before
+		 * descriptor is initialized. Otherwise, hardware can read
+		 * stale descriptor fields.
+		 */
+		wmb();
+		iowrite32(buf->index, &wq->ctrl->posted_index);
+	}
+	wq->to_use = buf;
+
+	wq->ring.desc_avail--;
+}
+
+static inline void svnic_wq_service(struct vnic_wq *wq,
+	struct cq_desc *cq_desc, u16 completed_index,
+	void (*buf_service)(struct vnic_wq *wq,
+	struct cq_desc *cq_desc, struct vnic_wq_buf *buf, void *opaque),
+	void *opaque)
+{
+	struct vnic_wq_buf *buf;
+
+	buf = wq->to_clean;
+	while (1) {
+
+		(*buf_service)(wq, cq_desc, buf, opaque);
+
+		wq->ring.desc_avail++;
+
+		wq->to_clean = buf->next;
+
+		if (buf->index == completed_index)
+			break;
+
+		buf = wq->to_clean;
+	}
+}
+
+void svnic_wq_free(struct vnic_wq *wq);
+int svnic_wq_alloc(struct vnic_dev *vdev, struct vnic_wq *wq,
+	unsigned int index, unsigned int desc_count, unsigned int desc_size);
+int vnic_wq_devcmd2_alloc(struct vnic_dev *vdev, struct vnic_wq *wq,
+		unsigned int desc_count, unsigned int desc_size);
+void vnic_wq_init_start(struct vnic_wq *wq, unsigned int cq_index,
+		unsigned int fetch_index, unsigned int post_index,
+		unsigned int error_interrupt_enable,
+		unsigned int error_interrupt_offset);
+
+void svnic_wq_init(struct vnic_wq *wq, unsigned int cq_index,
+	unsigned int error_interrupt_enable,
+	unsigned int error_interrupt_offset);
+unsigned int svnic_wq_error_status(struct vnic_wq *wq);
+void svnic_wq_enable(struct vnic_wq *wq);
+int svnic_wq_disable(struct vnic_wq *wq);
+void svnic_wq_clean(struct vnic_wq *wq,
+	void (*buf_clean)(struct vnic_wq *wq, struct vnic_wq_buf *buf));
+#endif /* _VNIC_WQ_H_ */