scsi: cxlflash: Remove port configuration assumptions

At present, the cxlflash driver only supports hardware with two FC ports. The
code was initially designed with this assumption and is dependent on having
two FC ports - adding more ports will break logic within the driver.

To mitigate this issue, remove the existing port assumptions and transition
the code to support more than two ports. As a side effect, clarify the
interpretation of the DK_CXLFLASH_ALL_PORTS_ACTIVE flag.

Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 58 insertions, 31 deletions

diff --git a/drivers/scsi/cxlflash/vlun.c b/drivers/scsi/cxlflash/vlun.c
index 7aa06ef229fd..067605b80fcd 100644
--- a/drivers/scsi/cxlflash/vlun.c
+++ b/drivers/scsi/cxlflash/vlun.c
@@ -819,8 +819,8 @@ int cxlflash_vlun_resize(struct scsi_device *sdev,
 void cxlflash_restore_luntable(struct cxlflash_cfg *cfg)
 {
 	struct llun_info *lli, *temp;
-	u32 chan;
 	u32 lind;
+	int k;
 	struct afu *afu = cfg->afu;
 	struct device *dev = &cfg->dev->dev;
 	struct sisl_global_map __iomem *agm = &afu->afu_map->global;
@@ -832,33 +832,41 @@ void cxlflash_restore_luntable(struct cxlflash_cfg *cfg)
 			continue;
 
 		lind = lli->lun_index;
+		dev_dbg(dev, "%s: Virtual LUNs on slot %d:\n", __func__, lind);
 
-		if (lli->port_sel == BOTH_PORTS) {
-			writeq_be(lli->lun_id[0], &agm->fc_port[0][lind]);
-			writeq_be(lli->lun_id[1], &agm->fc_port[1][lind]);
-			dev_dbg(dev, "%s: Virtual LUN on slot %d  id0=%llx "
-				"id1=%llx\n", __func__, lind,
-				lli->lun_id[0], lli->lun_id[1]);
-		} else {
-			chan = PORT2CHAN(lli->port_sel);
-			writeq_be(lli->lun_id[chan], &agm->fc_port[chan][lind]);
-			dev_dbg(dev, "%s: Virtual LUN on slot %d chan=%d "
-				"id=%llx\n", __func__, lind, chan,
-				lli->lun_id[chan]);
-		}
+		for (k = 0; k < cfg->num_fc_ports; k++)
+			if (lli->port_sel & (1 << k)) {
+				writeq_be(lli->lun_id[k],
+					  &agm->fc_port[k][lind]);
+				dev_dbg(dev, "\t%d=%llx\n", k, lli->lun_id[k]);
+			}
 	}
 
 	mutex_unlock(&global.mutex);
 }
 
 /**
+ * get_num_ports() - compute number of ports from port selection mask
+ * @psm:	Port selection mask.
+ *
+ * Return: Population count of port selection mask
+ */
+static inline u8 get_num_ports(u32 psm)
+{
+	static const u8 bits[16] = { 0, 1, 1, 2, 1, 2, 2, 3,
+				     1, 2, 2, 3, 2, 3, 3, 4 };
+
+	return bits[psm & 0xf];
+}
+
+/**
  * init_luntable() - write an entry in the LUN table
  * @cfg:	Internal structure associated with the host.
  * @lli:	Per adapter LUN information structure.
  *
- * On successful return, a LUN table entry is created.
- * At the top for LUNs visible on both ports.
- * At the bottom for LUNs visible only on one port.
+ * On successful return, a LUN table entry is created:
+ *	- at the top for LUNs visible on multiple ports.
+ *	- at the bottom for LUNs visible only on one port.
  *
  * Return: 0 on success, -errno on failure
  */
@@ -866,7 +874,9 @@ static int init_luntable(struct cxlflash_cfg *cfg, struct llun_info *lli)
 {
 	u32 chan;
 	u32 lind;
+	u32 nports;
 	int rc = 0;
+	int k;
 	struct afu *afu = cfg->afu;
 	struct device *dev = &cfg->dev->dev;
 	struct sisl_global_map __iomem *agm = &afu->afu_map->global;
@@ -876,29 +886,46 @@ static int init_luntable(struct cxlflash_cfg *cfg, struct llun_info *lli)
 	if (lli->in_table)
 		goto out;
 
-	if (lli->port_sel == BOTH_PORTS) {
+	nports = get_num_ports(lli->port_sel);
+	if (nports == 0 || nports > cfg->num_fc_ports) {
+		WARN(1, "Unsupported port configuration nports=%u", nports);
+		rc = -EIO;
+		goto out;
+	}
+
+	if (nports > 1) {
 		/*
-		 * If this LUN is visible from both ports, we will put
+		 * When LUN is visible from multiple ports, we will put
 		 * it in the top half of the LUN table.
 		 */
-		if ((cfg->promote_lun_index == cfg->last_lun_index[0]) ||
-		    (cfg->promote_lun_index == cfg->last_lun_index[1])) {
-			rc = -ENOSPC;
-			goto out;
+		for (k = 0; k < cfg->num_fc_ports; k++) {
+			if (!(lli->port_sel & (1 << k)))
+				continue;
+
+			if (cfg->promote_lun_index == cfg->last_lun_index[k]) {
+				rc = -ENOSPC;
+				goto out;
+			}
 		}
 
 		lind = lli->lun_index = cfg->promote_lun_index;
-		writeq_be(lli->lun_id[0], &agm->fc_port[0][lind]);
-		writeq_be(lli->lun_id[1], &agm->fc_port[1][lind]);
+		dev_dbg(dev, "%s: Virtual LUNs on slot %d:\n", __func__, lind);
+
+		for (k = 0; k < cfg->num_fc_ports; k++) {
+			if (!(lli->port_sel & (1 << k)))
+				continue;
+
+			writeq_be(lli->lun_id[k], &agm->fc_port[k][lind]);
+			dev_dbg(dev, "\t%d=%llx\n", k, lli->lun_id[k]);
+		}
+
 		cfg->promote_lun_index++;
-		dev_dbg(dev, "%s: Virtual LUN on slot %d  id0=%llx id1=%llx\n",
-			__func__, lind, lli->lun_id[0], lli->lun_id[1]);
 	} else {
 		/*
-		 * If this LUN is visible only from one port, we will put
+		 * When LUN is visible only from one port, we will put
 		 * it in the bottom half of the LUN table.
 		 */
-		chan = PORT2CHAN(lli->port_sel);
+		chan = PORTMASK2CHAN(lli->port_sel);
 		if (cfg->promote_lun_index == cfg->last_lun_index[chan]) {
 			rc = -ENOSPC;
 			goto out;
@@ -907,7 +934,7 @@ static int init_luntable(struct cxlflash_cfg *cfg, struct llun_info *lli)
 		lind = lli->lun_index = cfg->last_lun_index[chan];
 		writeq_be(lli->lun_id[chan], &agm->fc_port[chan][lind]);
 		cfg->last_lun_index[chan]--;
-		dev_dbg(dev, "%s: Virtual LUN on slot %d  chan=%d id=%llx\n",
+		dev_dbg(dev, "%s: Virtual LUNs on slot %d:\n\t%d=%llx\n",
 			__func__, lind, chan, lli->lun_id[chan]);
 	}
 
@@ -1016,7 +1043,7 @@ int cxlflash_disk_virtual_open(struct scsi_device *sdev, void *arg)
 	virt->last_lba = last_lba;
 	virt->rsrc_handle = rsrc_handle;
 
-	if (lli->port_sel == BOTH_PORTS)
+	if (get_num_ports(lli->port_sel) > 1)
 		virt->hdr.return_flags |= DK_CXLFLASH_ALL_PORTS_ACTIVE;
 out:
 	if (likely(ctxi))