[PATCH 2/2][SRU][H][I][OEM-5.13][OEM-5.14] UBUNTU: SAUCE: e1000e: Fixing packet loss issues on new platforms

[AceLan Kao]

From: Sasha Neftin <sasha.neftin at intel.com>

BugLink: https://bugs.launchpad.net/bugs/1930754

Update the HW MAC initialization flow. Do not gate DMA clock from
the modPHY block. Keeping this clock will prevent drop packets sent
in burst mode on the Kumeran interface.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=213651
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=213377
Fixes: bc7f75fa9788 ("New pci-express e1000 driver");
Signed-off-by: Sasha Neftin <sasha.neftin at intel.com>
Tested-by: Mark Pearson <markpearson at lenovo.com>
(cherry picked from
https://patchwork.ozlabs.org/project/intel-wired-lan/patch/20210922065542.3780389-1-sasha.neftin@intel.com/)
Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao at canonical.com>
---
 drivers/net/ethernet/intel/e1000e/ich8lan.c | 11 ++++++++++-
 drivers/net/ethernet/intel/e1000e/ich8lan.h |  3 +++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.c b/drivers/net/ethernet/intel/e1000e/ich8lan.c
index 2193c7d8cb815..65aa90c6f2dd7 100644
--- a/drivers/net/ethernet/intel/e1000e/ich8lan.c
+++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c
@@ -4792,7 +4792,7 @@ static s32 e1000_reset_hw_ich8lan(struct e1000_hw *hw)
 static s32 e1000_init_hw_ich8lan(struct e1000_hw *hw)
 {
 	struct e1000_mac_info *mac = &hw->mac;
-	u32 ctrl_ext, txdctl, snoop;
+	u32 ctrl_ext, txdctl, snoop, fflt_dbg;
 	s32 ret_val;
 	u16 i;
 
@@ -4851,6 +4851,15 @@ static s32 e1000_init_hw_ich8lan(struct e1000_hw *hw)
 		snoop = (u32)~(PCIE_NO_SNOOP_ALL);
 	e1000e_set_pcie_no_snoop(hw, snoop);
 
+	/* Enable workaround for packet loss issue on TGP PCH
+	 * Do not gate DMA clock from the modPHY block
+	 */
+	if (mac->type >= e1000_pch_tgp) {
+		fflt_dbg = er32(FFLT_DBG);
+		fflt_dbg |= E1000_FFLT_DBG_DONT_GATE_WAKE_DMA_CLK;
+		ew32(FFLT_DBG, fflt_dbg);
+	}
+
 	ctrl_ext = er32(CTRL_EXT);
 	ctrl_ext |= E1000_CTRL_EXT_RO_DIS;
 	ew32(CTRL_EXT, ctrl_ext);
diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.h b/drivers/net/ethernet/intel/e1000e/ich8lan.h
index 9b145f6248a8f..4e4da2b265804 100644
--- a/drivers/net/ethernet/intel/e1000e/ich8lan.h
+++ b/drivers/net/ethernet/intel/e1000e/ich8lan.h
@@ -286,6 +286,9 @@
 /* Proprietary Latency Tolerance Reporting PCI Capability */
 #define E1000_PCI_LTR_CAP_LPT		0xA8
 
+/* Don't gate wake DMA clock */
+#define E1000_FFLT_DBG_DONT_GATE_WAKE_DMA_CLK	0x1000
+
 void e1000e_write_protect_nvm_ich8lan(struct e1000_hw *hw);
 void e1000e_set_kmrn_lock_loss_workaround_ich8lan(struct e1000_hw *hw,
 						  bool state);
-- 
2.25.1