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>

3 files changed, 8 insertions, 0 deletions

diff --git a/drivers/net/igb/e1000_nvm.c b/drivers/net/igb/e1000_nvm.c
index 7dcd65cede56..40407124e722 100644
--- a/drivers/net/igb/e1000_nvm.c
+++ b/drivers/net/igb/e1000_nvm.c
@@ -285,6 +285,7 @@ static s32 igb_ready_nvm_eeprom(struct e1000_hw *hw)
                 /* Clear SK and CS */
                 eecd &= ~(E1000_EECD_CS | E1000_EECD_SK);
                 wr32(E1000_EECD, eecd);
+                wrfl();
                 udelay(1);
                 timeout = NVM_MAX_RETRY_SPI;
 
diff --git a/drivers/net/igb/igb_ethtool.c b/drivers/net/igb/igb_ethtool.c
index ff244ce803ce..414b0225be89 100644
--- a/drivers/net/igb/igb_ethtool.c
+++ b/drivers/net/igb/igb_ethtool.c
@@ -1225,6 +1225,7 @@ static int igb_intr_test(struct igb_adapter *adapter, u64 *data)
 
         /* Disable all the interrupts */
         wr32(E1000_IMC, ~0);
+        wrfl();
         msleep(10);
 
         /* Define all writable bits for ICS */
@@ -1268,6 +1269,7 @@ static int igb_intr_test(struct igb_adapter *adapter, u64 *data)
 
                         wr32(E1000_IMC, mask);
                         wr32(E1000_ICS, mask);
+                        wrfl();
                         msleep(10);
 
                         if (adapter->test_icr & mask) {
@@ -1289,6 +1291,7 @@ static int igb_intr_test(struct igb_adapter *adapter, u64 *data)
 
                 wr32(E1000_IMS, mask);
                 wr32(E1000_ICS, mask);
+                wrfl();
                 msleep(10);
 
                 if (!(adapter->test_icr & mask)) {
@@ -1310,6 +1313,7 @@ static int igb_intr_test(struct igb_adapter *adapter, u64 *data)
 
                         wr32(E1000_IMC, ~mask);
                         wr32(E1000_ICS, ~mask);
+                        wrfl();
                         msleep(10);
 
                         if (adapter->test_icr & mask) {
@@ -1321,6 +1325,7 @@ static int igb_intr_test(struct igb_adapter *adapter, u64 *data)
 
         /* Disable all the interrupts */
         wr32(E1000_IMC, ~0);
+        wrfl();
         msleep(10);
 
         /* Unhook test interrupt handler */
diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
index dc599059512a..ae3937e8cdef 100644
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -1052,6 +1052,7 @@ msi_only:
                 kfree(adapter->vf_data);
                 adapter->vf_data = NULL;
                 wr32(E1000_IOVCTL, E1000_IOVCTL_REUSE_VFQ);
+                wrfl();
                 msleep(100);
                 dev_info(&adapter->pdev->dev, "IOV Disabled\n");
         }
@@ -2198,6 +2199,7 @@ static void __devexit igb_remove(struct pci_dev *pdev)
                 kfree(adapter->vf_data);
                 adapter->vf_data = NULL;
                 wr32(E1000_IOVCTL, E1000_IOVCTL_REUSE_VFQ);
+                wrfl();
                 msleep(100);
                 dev_info(&pdev->dev, "IOV Disabled\n");
         }