e1000e: i219 fix unit hang on reset and runtime D3
Unit hang may occur if multiple descriptors are available in the rings
during reset or runtime suspend. This state can be detected by testing
bit 8 in the FEXTNVM7 register. If this bit is set and there are pending
descriptors in one of the rings, we must flush them prior to reset. Same
applies entering runtime suspend.
Signed-off-by: Yanir Lubetkin <yanirx.lubetkin@intel.com>
Reviewed-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 7dd2c11..76b1a90 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -3788,6 +3788,106 @@
}
/**
+ * e1000_flush_tx_ring - remove all descriptors from the tx_ring
+ *
+ * We want to clear all pending descriptors from the TX ring.
+ * zeroing happens when the HW reads the regs. We assign the ring itself as
+ * the data of the next descriptor. We don't care about the data we are about
+ * to reset the HW.
+ */
+static void e1000_flush_tx_ring(struct e1000_adapter *adapter)
+{
+ struct e1000_hw *hw = &adapter->hw;
+ struct e1000_ring *tx_ring = adapter->tx_ring;
+ struct e1000_tx_desc *tx_desc = NULL;
+ u32 tdt, tctl, txd_lower = E1000_TXD_CMD_IFCS;
+ u16 size = 512;
+
+ tctl = er32(TCTL);
+ ew32(TCTL, tctl | E1000_TCTL_EN);
+ tdt = er32(TDT(0));
+ BUG_ON(tdt != tx_ring->next_to_use);
+ tx_desc = E1000_TX_DESC(*tx_ring, tx_ring->next_to_use);
+ tx_desc->buffer_addr = tx_ring->dma;
+
+ tx_desc->lower.data = cpu_to_le32(txd_lower | size);
+ tx_desc->upper.data = 0;
+ /* flush descriptors to memory before notifying the HW */
+ wmb();
+ tx_ring->next_to_use++;
+ if (tx_ring->next_to_use == tx_ring->count)
+ tx_ring->next_to_use = 0;
+ ew32(TDT(0), tx_ring->next_to_use);
+ mmiowb();
+ usleep_range(200, 250);
+}
+
+/**
+ * e1000_flush_rx_ring - remove all descriptors from the rx_ring
+ *
+ * Mark all descriptors in the RX ring as consumed and disable the rx ring
+ */
+static void e1000_flush_rx_ring(struct e1000_adapter *adapter)
+{
+ u32 rctl, rxdctl;
+ struct e1000_hw *hw = &adapter->hw;
+
+ rctl = er32(RCTL);
+ ew32(RCTL, rctl & ~E1000_RCTL_EN);
+ e1e_flush();
+ usleep_range(100, 150);
+
+ rxdctl = er32(RXDCTL(0));
+ /* zero the lower 14 bits (prefetch and host thresholds) */
+ rxdctl &= 0xffffc000;
+
+ /* update thresholds: prefetch threshold to 31, host threshold to 1
+ * and make sure the granularity is "descriptors" and not "cache lines"
+ */
+ rxdctl |= (0x1F | (1 << 8) | E1000_RXDCTL_THRESH_UNIT_DESC);
+
+ ew32(RXDCTL(0), rxdctl);
+ /* momentarily enable the RX ring for the changes to take effect */
+ ew32(RCTL, rctl | E1000_RCTL_EN);
+ e1e_flush();
+ usleep_range(100, 150);
+ ew32(RCTL, rctl & ~E1000_RCTL_EN);
+}
+
+/**
+ * e1000_flush_desc_rings - remove all descriptors from the descriptor rings
+ *
+ * In i219, the descriptor rings must be emptied before resetting the HW
+ * or before changing the device state to D3 during runtime (runtime PM).
+ *
+ * Failure to do this will cause the HW to enter a unit hang state which can
+ * only be released by PCI reset on the device
+ *
+ */
+
+static void e1000_flush_desc_rings(struct e1000_adapter *adapter)
+{
+ u32 hang_state;
+ u32 fext_nvm11, tdlen;
+ struct e1000_hw *hw = &adapter->hw;
+
+ /* First, disable MULR fix in FEXTNVM11 */
+ fext_nvm11 = er32(FEXTNVM11);
+ fext_nvm11 |= E1000_FEXTNVM11_DISABLE_MULR_FIX;
+ ew32(FEXTNVM11, fext_nvm11);
+ /* do nothing if we're not in faulty state, or if the queue is empty */
+ tdlen = er32(TDLEN(0));
+ hang_state = er32(FEXTNVM7);
+ if ((hang_state & E1000_FEXTNVM7_NEED_DESCRING_FLUSH) || tdlen)
+ return;
+ e1000_flush_tx_ring(adapter);
+ /* recheck, maybe the fault is caused by the rx ring */
+ hang_state = er32(FEXTNVM7);
+ if (hang_state & E1000_FEXTNVM7_NEED_DESCRING_FLUSH)
+ e1000_flush_rx_ring(adapter);
+}
+
+/**
* e1000e_reset - bring the hardware into a known good state
*
* This function boots the hardware and enables some settings that
@@ -4115,6 +4215,8 @@
spin_unlock(&adapter->stats64_lock);
e1000e_flush_descriptors(adapter);
+ if (hw->mac.type == e1000_pch_spt)
+ e1000_flush_desc_rings(adapter);
e1000_clean_tx_ring(adapter->tx_ring);
e1000_clean_rx_ring(adapter->rx_ring);