e1000e: workaround DMA unit hang on I218

At 1000Mbps link speed, one of the MAC's internal clocks can be stopped for
up to 4us when entering K1 (a power mode of the MAC-PHY interconnect).  If
the MAC is waiting for completion indications for 2 DMA write requests into
Host memory (e.g. descriptor writeback or Rx packet writing) and the
indications occur while the clock is stopped, both indications will be
missed by the MAC causing the MAC to wait for the completion indications
and be unable to generate further DMA write requests.  This results in an
apparent hardware hang.

Work-around the issue by disabling the de-assertion of the clock request
when 1000Mbps link is acquired (K1 must be disabled while doing this).

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.c b/drivers/net/ethernet/intel/e1000e/ich8lan.c
index dff7bff8b8e0f1d5ee4e6ca4af510516b3d7fd49..121a865c7fbd12855b32b5dff2883332f3b9485b 100644 (file)
--- a/drivers/net/ethernet/intel/e1000e/ich8lan.c
+++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c
@@ -781,6 +781,59 @@ release:
        return ret_val;
 }
 
+/**
+ *  e1000_k1_workaround_lpt_lp - K1 workaround on Lynxpoint-LP
+ *  @hw:   pointer to the HW structure
+ *  @link: link up bool flag
+ *
+ *  When K1 is enabled for 1Gbps, the MAC can miss 2 DMA completion indications
+ *  preventing further DMA write requests.  Workaround the issue by disabling
+ *  the de-assertion of the clock request when in 1Gpbs mode.
+ **/
+static s32 e1000_k1_workaround_lpt_lp(struct e1000_hw *hw, bool link)
+{
+       u32 fextnvm6 = er32(FEXTNVM6);
+       s32 ret_val = 0;
+
+       if (link && (er32(STATUS) & E1000_STATUS_SPEED_1000)) {
+               u16 kmrn_reg;
+
+               ret_val = hw->phy.ops.acquire(hw);
+               if (ret_val)
+                       return ret_val;
+
+               ret_val =
+                   e1000e_read_kmrn_reg_locked(hw, E1000_KMRNCTRLSTA_K1_CONFIG,
+                                               &kmrn_reg);
+               if (ret_val)
+                       goto release;
+
+               ret_val =
+                   e1000e_write_kmrn_reg_locked(hw,
+                                                E1000_KMRNCTRLSTA_K1_CONFIG,
+                                                kmrn_reg &
+                                                ~E1000_KMRNCTRLSTA_K1_ENABLE);
+               if (ret_val)
+                       goto release;
+
+               usleep_range(10, 20);
+
+               ew32(FEXTNVM6, fextnvm6 | E1000_FEXTNVM6_REQ_PLL_CLK);
+
+               ret_val =
+                   e1000e_write_kmrn_reg_locked(hw,
+                                                E1000_KMRNCTRLSTA_K1_CONFIG,
+                                                kmrn_reg);
+release:
+               hw->phy.ops.release(hw);
+       } else {
+               /* clear FEXTNVM6 bit 8 on link down or 10/100 */
+               ew32(FEXTNVM6, fextnvm6 & ~E1000_FEXTNVM6_REQ_PLL_CLK);
+       }
+
+       return ret_val;
+}
+
 /**
  *  e1000_check_for_copper_link_ich8lan - Check for link (Copper)
  *  @hw: pointer to the HW structure
@@ -818,6 +871,14 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw)
                        return ret_val;
        }
 
+       /* Work-around I218 hang issue */
+       if ((hw->adapter->pdev->device == E1000_DEV_ID_PCH_LPTLP_I218_LM) ||
+           (hw->adapter->pdev->device == E1000_DEV_ID_PCH_LPTLP_I218_V)) {
+               ret_val = e1000_k1_workaround_lpt_lp(hw, link);
+               if (ret_val)
+                       return ret_val;
+       }
+
        /* Clear link partner's EEE ability */
        hw->dev_spec.ich8lan.eee_lp_ability = 0;
 
@@ -3954,8 +4015,16 @@ void e1000_suspend_workarounds_ich8lan(struct e1000_hw *hw)
 
        phy_ctrl = er32(PHY_CTRL);
        phy_ctrl |= E1000_PHY_CTRL_GBE_DISABLE;
+
        if (hw->phy.type == e1000_phy_i217) {
-               u16 phy_reg;
+               u16 phy_reg, device_id = hw->adapter->pdev->device;
+
+               if ((device_id == E1000_DEV_ID_PCH_LPTLP_I218_LM) ||
+                   (device_id == E1000_DEV_ID_PCH_LPTLP_I218_V)) {
+                       u32 fextnvm6 = er32(FEXTNVM6);
+
+                       ew32(FEXTNVM6, fextnvm6 & ~E1000_FEXTNVM6_REQ_PLL_CLK);
+               }
 
                ret_val = hw->phy.ops.acquire(hw);
                if (ret_val)

diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.h b/drivers/net/ethernet/intel/e1000e/ich8lan.h
index b6d3174d7d2d737ff599b2f3f17d6bb7bb1b7cc6..8bf4655c2e17f25a26b70bb6c0ad268034bf8c04 100644 (file)
--- a/drivers/net/ethernet/intel/e1000e/ich8lan.h
+++ b/drivers/net/ethernet/intel/e1000e/ich8lan.h
@@ -92,6 +92,8 @@
 #define E1000_FEXTNVM4_BEACON_DURATION_8USEC   0x7
 #define E1000_FEXTNVM4_BEACON_DURATION_16USEC  0x3
 
+#define E1000_FEXTNVM6_REQ_PLL_CLK     0x00000100
+
 #define PCIE_ICH8_SNOOP_ALL    PCIE_NO_SNOOP_ALL
 
 #define E1000_ICH_RAR_ENTRIES  7

diff --git a/drivers/net/ethernet/intel/e1000e/regs.h b/drivers/net/ethernet/intel/e1000e/regs.h
index 794fe14976667059b3cb33924f49dec84cde2aef..a7e6a3e37257b34f200ba01c3525fd3269964943 100644 (file)
--- a/drivers/net/ethernet/intel/e1000e/regs.h
+++ b/drivers/net/ethernet/intel/e1000e/regs.h
@@ -42,6 +42,7 @@
 #define E1000_FEXTNVM  0x00028 /* Future Extended NVM - RW */
 #define E1000_FEXTNVM3 0x0003C /* Future Extended NVM 3 - RW */
 #define E1000_FEXTNVM4 0x00024 /* Future Extended NVM 4 - RW */
+#define E1000_FEXTNVM6 0x00010 /* Future Extended NVM 6 - RW */
 #define E1000_FEXTNVM7 0x000E4 /* Future Extended NVM 7 - RW */
 #define E1000_FCT      0x00030 /* Flow Control Type - RW */
 #define E1000_VET      0x00038 /* VLAN Ether Type - RW */