intel drivers: repair missing flush operations

after review of all intel drivers, found several instances where
drivers had the incorrect pattern of:
memory mapped write();
delay();

which should always be:
memory mapped write();
write flush(); /* aka memory mapped read */
delay();

explanation:
The reason for including the flush is that writes can be held
(posted) in PCI/PCIe bridges, but the read always has to complete
synchronously and therefore has to flush all pending writes to a
device.  If a write is held and followed by a delay, the delay
means nothing because the write may not have reached hardware
(maybe even not until the next read)

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by:  Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/net/igbvf/netdev.c b/drivers/net/igbvf/netdev.c
index 1330c8e932d..40ed066e3ef 100644
--- a/drivers/net/igbvf/netdev.c
+++ b/drivers/net/igbvf/netdev.c
@@ -1226,6 +1226,7 @@ static void igbvf_configure_tx(struct igbvf_adapter *adapter)
 	/* disable transmits */
 	txdctl = er32(TXDCTL(0));
 	ew32(TXDCTL(0), txdctl & ~E1000_TXDCTL_QUEUE_ENABLE);
+	e1e_flush();
 	msleep(10);
 
 	/* Setup the HW Tx Head and Tail descriptor pointers */
@@ -1306,6 +1307,7 @@ static void igbvf_configure_rx(struct igbvf_adapter *adapter)
 	/* disable receives */
 	rxdctl = er32(RXDCTL(0));
 	ew32(RXDCTL(0), rxdctl & ~E1000_RXDCTL_QUEUE_ENABLE);
+	e1e_flush();
 	msleep(10);
 
 	rdlen = rx_ring->count * sizeof(union e1000_adv_rx_desc);