scsi: lpfc: cleanup: convert eq_delay to usdelay

Review of the eq coalescing logic showed the code was a bit fragmented.
Sometimes it would save/set via an interrupt max value, while in others it
would do so via a usdelay. There were also two places changing eq delay,
one place that issued mailbox commands, and another that changed via
register writes if supported.

Clean this up by:

 - Standardizing the operation of lpfc_modify_hba_eq_delay() routine so
   that it is always told of a us delay to impose. The routine then chooses
   the best way to set that - via register or via mbx.

 - Rather than two value types stored in eq->q_mode (usdelay if change via
   register, imax if change via mbox) - q_mode always contains usdelay.
   Before any value change, old vs new value is compared and only if
   different is a change done.

 - Revised the dmult calculation. dmult is not set based on overall imax
   divided by hardware queues - instead imax applies to a single cpu and
   the value will be replicated to all cpus.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/drivers/scsi/lpfc/lpfc_attr.c b/drivers/scsi/lpfc/lpfc_attr.c
index fc7f80d68638..ed8caeefe3a2 100644
--- a/drivers/scsi/lpfc/lpfc_attr.c
+++ b/drivers/scsi/lpfc/lpfc_attr.c
@@ -4935,6 +4935,7 @@ lpfc_fcp_imax_store(struct device *dev, struct device_attribute *attr,
 	struct Scsi_Host *shost = class_to_shost(dev);
 	struct lpfc_vport *vport = (struct lpfc_vport *)shost->hostdata;
 	struct lpfc_hba *phba = vport->phba;
+	uint32_t usdelay;
 	int val = 0, i;
 
 	/* fcp_imax is only valid for SLI4 */
@@ -4958,9 +4959,14 @@ lpfc_fcp_imax_store(struct device *dev, struct device_attribute *attr,
 	phba->cfg_fcp_imax = (uint32_t)val;
 	phba->initial_imax = phba->cfg_fcp_imax;
 
+	if (phba->cfg_fcp_imax)
+		usdelay = LPFC_SEC_TO_USEC / phba->cfg_fcp_imax;
+	else
+		usdelay = 0;
+
 	for (i = 0; i < phba->cfg_irq_chann; i += LPFC_MAX_EQ_DELAY_EQID_CNT)
 		lpfc_modify_hba_eq_delay(phba, i, LPFC_MAX_EQ_DELAY_EQID_CNT,
-					 val);
+					 usdelay);
 
 	return strlen(buf);
 }