ixgbe: force unlock on timeout

The semaphore can be in locked state upon driver load, particularly
on 82598 if a machine is rebooted due to panic and the semaphore was
acquired just prior to the panic.

This patch unlocks the semaphore if it times out.

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 22 insertions, 0 deletions

diff --git a/drivers/net/ixgbe/ixgbe_common.c b/drivers/net/ixgbe/ixgbe_common.c
index c4730cd39b22..b894b42a741c 100644
--- a/drivers/net/ixgbe/ixgbe_common.c
+++ b/drivers/net/ixgbe/ixgbe_common.c
@@ -1189,6 +1189,28 @@ static s32 ixgbe_get_eeprom_semaphore(struct ixgbe_hw *hw)
                 udelay(50);
         }
 
+        if (i == timeout) {
+                hw_dbg(hw, "Driver can't access the Eeprom - SMBI Semaphore "
+                       "not granted.\n");
+                /*
+                 * this release is particularly important because our attempts
+                 * above to get the semaphore may have succeeded, and if there
+                 * was a timeout, we should unconditionally clear the semaphore
+                 * bits to free the driver to make progress
+                 */
+                ixgbe_release_eeprom_semaphore(hw);
+
+                udelay(50);
+                /*
+                 * one last try
+                 * If the SMBI bit is 0 when we read it, then the bit will be
+                 * set and we have the semaphore
+                 */
+                swsm = IXGBE_READ_REG(hw, IXGBE_SWSM);
+                if (!(swsm & IXGBE_SWSM_SMBI))
+                        status = 0;
+        }
+
         /* Now get the semaphore between SW/FW through the SWESMBI bit */
         if (status == 0) {
                 for (i = 0; i < timeout; i++) {