[SCSI] qla2xxx: Add support to dynamically enable/disable ZIO.

ISP23xx and ISP24xx chips have support for an adaptive
method of posting SCSI command completions for multiple SCSI
commands during a single system interrupt.

SCSI commands are placed on the system response queue
without interrupting the host until 1) a delay timer
expires; or 2) a SCSI command completes with an error.

As long as the host software (qla2xxx) services the response
queue for completions (this polling is done during
queuecommand()) within the 'delay timer' period, the
firmware will not generate system interrupt.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 40 insertions, 13 deletions

diff --git a/drivers/scsi/qla2xxx/qla_init.c b/drivers/scsi/qla2xxx/qla_init.c
index 6fc8bbae9398..9e36fbd9245a 100644
--- a/drivers/scsi/qla2xxx/qla_init.c
+++ b/drivers/scsi/qla2xxx/qla_init.c
@@ -1372,7 +1372,6 @@ qla2x00_nvram_config(scsi_qla_host_t *ha)
 	nvram_t         *nv = (nvram_t *)ha->request_ring;
 	uint8_t         *ptr = (uint8_t *)ha->request_ring;
 	struct device_reg_2xxx __iomem *reg = &ha->iobase->isp;
-	uint8_t         timer_mode;
 
 	rval = QLA_SUCCESS;
 
@@ -1650,22 +1649,26 @@ qla2x00_nvram_config(scsi_qla_host_t *ha)
 
 		ha->flags.process_response_queue = 1;
 	} else {
-		/* Enable ZIO -- Support mode 5 only. */
-		timer_mode = icb->add_firmware_options[0] &
-		    (BIT_3 | BIT_2 | BIT_1 | BIT_0);
+		/* Enable ZIO. */
+		if (!ha->flags.init_done) {
+			ha->zio_mode = icb->add_firmware_options[0] &
+			    (BIT_3 | BIT_2 | BIT_1 | BIT_0);
+			ha->zio_timer = icb->interrupt_delay_timer ?
+			    icb->interrupt_delay_timer: 2;
+		}
 		icb->add_firmware_options[0] &=
 		    ~(BIT_3 | BIT_2 | BIT_1 | BIT_0);
-		if (ql2xenablezio)
-			timer_mode = BIT_2 | BIT_0;
-		if (timer_mode == (BIT_2 | BIT_0)) {
-			DEBUG2(printk("scsi(%ld): ZIO enabled; timer delay "
-			    "(%d).\n", ha->host_no, ql2xintrdelaytimer));
+		ha->flags.process_response_queue = 0;
+		if (ha->zio_mode != QLA_ZIO_DISABLED) {
+			DEBUG2(printk("scsi(%ld): ZIO mode %d enabled; timer "
+			    "delay (%d us).\n", ha->host_no, ha->zio_mode,
+			    ha->zio_timer * 100));
 			qla_printk(KERN_INFO, ha,
-			    "ZIO enabled; timer delay (%d).\n",
-			    ql2xintrdelaytimer);
+			    "ZIO mode %d enabled; timer delay (%d us).\n",
+			    ha->zio_mode, ha->zio_timer * 100);
 
-			icb->add_firmware_options[0] |= timer_mode;
-			icb->interrupt_delay_timer = ql2xintrdelaytimer;
+			icb->add_firmware_options[0] |= (uint8_t)ha->zio_mode;
+			icb->interrupt_delay_timer = (uint8_t)ha->zio_timer;
 			ha->flags.process_response_queue = 1;
 		}
 	}
@@ -3442,6 +3445,30 @@ qla24xx_nvram_config(scsi_qla_host_t *ha)
 	if (ql2xloginretrycount)
 		ha->login_retry_count = ql2xloginretrycount;
 
+	/* Enable ZIO. */
+	if (!ha->flags.init_done) {
+		ha->zio_mode = le32_to_cpu(icb->firmware_options_2) &
+		    (BIT_3 | BIT_2 | BIT_1 | BIT_0);
+		ha->zio_timer = le16_to_cpu(icb->interrupt_delay_timer) ?
+		    le16_to_cpu(icb->interrupt_delay_timer): 2;
+	}
+	icb->firmware_options_2 &= __constant_cpu_to_le32(
+	    ~(BIT_3 | BIT_2 | BIT_1 | BIT_0));
+	ha->flags.process_response_queue = 0;
+	if (ha->zio_mode != QLA_ZIO_DISABLED) {
+		DEBUG2(printk("scsi(%ld): ZIO mode %d enabled; timer delay "
+		    "(%d us).\n", ha->host_no, ha->zio_mode,
+		    ha->zio_timer * 100));
+		qla_printk(KERN_INFO, ha,
+		    "ZIO mode %d enabled; timer delay (%d us).\n",
+		    ha->zio_mode, ha->zio_timer * 100);
+
+		icb->firmware_options_2 |= cpu_to_le32(
+		    (uint32_t)ha->zio_mode);
+		icb->interrupt_delay_timer = cpu_to_le16(ha->zio_timer);
+		ha->flags.process_response_queue = 1;
+	}
+
 	if (rval) {
 		DEBUG2_3(printk(KERN_WARNING
 		    "scsi(%ld): NVRAM configuration failed!\n", ha->host_no));