From: Netanel Belgazal <netanel@amazon.com>
Date: Tue, 17 Oct 2017 07:33:56 +0000
Subject: net: ena: improve ENA driver boot time.
Patch-mainline: v4.15-rc1
Git-commit: 88aef2f51c9e3640268aca04a256b8f26cf6bdff
References: bsc#1083548

The ena admin commands timeout is in resolutions of 100ms.
Therefore, When the driver works in polling mode, it sleeps for 100ms
each time. The overall boot time of the ENA driver is ~1.5 sec.
To reduce the boot time, This change modifies the granularity of
the sleeps to 5ms.
This change improves the boot time to 220ms.

Signed-off-by: Netanel Belgazal <netanel@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/amazon/ena/ena_com.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/amazon/ena/ena_com.c
+++ b/drivers/net/ethernet/amazon/ena/ena_com.c
@@ -63,6 +63,8 @@
 
 #define ENA_REGS_ADMIN_INTR_MASK 1
 
+#define ENA_POLL_MS	5
+
 /*****************************************************************************/
 /*****************************************************************************/
 /*****************************************************************************/
@@ -533,7 +535,7 @@ static int ena_com_wait_and_process_admi
 			goto err;
 		}
 
-		msleep(100);
+		msleep(ENA_POLL_MS);
 	}
 
 	if (unlikely(comp_ctx->status == ENA_CMD_ABORTED)) {
@@ -746,6 +748,9 @@ static int wait_for_reset_state(struct e
 {
 	u32 val, i;
 
+	/* Convert timeout from resolution of 100ms to ENA_POLL_MS */
+	timeout = (timeout * 100) / ENA_POLL_MS;
+
 	for (i = 0; i < timeout; i++) {
 		val = ena_com_reg_bar_read32(ena_dev, ENA_REGS_DEV_STS_OFF);
 
@@ -758,8 +763,7 @@ static int wait_for_reset_state(struct e
 			exp_state)
 			return 0;
 
-		/* The resolution of the timeout is 100ms */
-		msleep(100);
+		msleep(ENA_POLL_MS);
 	}
 
 	return -ETIME;
@@ -1253,7 +1257,7 @@ void ena_com_wait_for_abort_completion(s
 	spin_lock_irqsave(&admin_queue->q_lock, flags);
 	while (atomic_read(&admin_queue->outstanding_cmds) != 0) {
 		spin_unlock_irqrestore(&admin_queue->q_lock, flags);
-		msleep(20);
+		msleep(ENA_POLL_MS);
 		spin_lock_irqsave(&admin_queue->q_lock, flags);
 	}
 	spin_unlock_irqrestore(&admin_queue->q_lock, flags);