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>
diff --git a/drivers/net/ixgbe/ixgbe_ethtool.c b/drivers/net/ixgbe/ixgbe_ethtool.c
index dc64955..82d4244 100644
--- a/drivers/net/ixgbe/ixgbe_ethtool.c
+++ b/drivers/net/ixgbe/ixgbe_ethtool.c
@@ -1378,6 +1378,7 @@
/* Disable all the interrupts */
IXGBE_WRITE_REG(&adapter->hw, IXGBE_EIMC, 0xFFFFFFFF);
+ IXGBE_WRITE_FLUSH(&adapter->hw);
usleep_range(10000, 20000);
/* Test each interrupt */
@@ -1398,6 +1399,7 @@
~mask & 0x00007FFF);
IXGBE_WRITE_REG(&adapter->hw, IXGBE_EICS,
~mask & 0x00007FFF);
+ IXGBE_WRITE_FLUSH(&adapter->hw);
usleep_range(10000, 20000);
if (adapter->test_icr & mask) {
@@ -1415,6 +1417,7 @@
adapter->test_icr = 0;
IXGBE_WRITE_REG(&adapter->hw, IXGBE_EIMS, mask);
IXGBE_WRITE_REG(&adapter->hw, IXGBE_EICS, mask);
+ IXGBE_WRITE_FLUSH(&adapter->hw);
usleep_range(10000, 20000);
if (!(adapter->test_icr &mask)) {
@@ -1435,6 +1438,7 @@
~mask & 0x00007FFF);
IXGBE_WRITE_REG(&adapter->hw, IXGBE_EICS,
~mask & 0x00007FFF);
+ IXGBE_WRITE_FLUSH(&adapter->hw);
usleep_range(10000, 20000);
if (adapter->test_icr) {
@@ -1446,6 +1450,7 @@
/* Disable all the interrupts */
IXGBE_WRITE_REG(&adapter->hw, IXGBE_EIMC, 0xFFFFFFFF);
+ IXGBE_WRITE_FLUSH(&adapter->hw);
usleep_range(10000, 20000);
/* Unhook test interrupt handler */