From 12e8addd320df995bfb2b00f51c233541f741ae4 Mon Sep 17 00:00:00 2001
From: Kevin Bowling <kbowling@FreeBSD.org>
Date: Tue, 10 Aug 2021 12:47:22 -0700
Subject: [PATCH] e1000: rctl/srrctl buffer size init, rfctl fix

Simplify the setup of srrctl.BSIZEPKT on igb class NICs.
Improve the setup of rctl.BSIZE on lem and em class NICs.
Don't try to touch rfctl on lem class NICs.
Manipulate rctl.BSEX correctly on lem and em class NICs.

Approved by:	markj
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D31457
---
 sys/dev/e1000/if_em.c | 76 ++++++++++++++++++++++++-------------------
 1 file changed, 43 insertions(+), 33 deletions(-)

diff --git a/sys/dev/e1000/if_em.c b/sys/dev/e1000/if_em.c
index 52d20e57519..33d5341ed8c 100644
--- a/sys/dev/e1000/if_em.c
+++ b/sys/dev/e1000/if_em.c
@@ -3170,6 +3170,7 @@ em_initialize_transmit_unit(if_ctx_t ctx)
  *  Enable receive unit.
  *
  **********************************************************************/
+#define BSIZEPKT_ROUNDUP ((1<<E1000_SRRCTL_BSIZEPKT_SHIFT)-1)
 
 static void
 em_initialize_receive_unit(if_ctx_t ctx)
@@ -3180,7 +3181,7 @@ em_initialize_receive_unit(if_ctx_t ctx)
 	struct e1000_hw	*hw = &adapter->hw;
 	struct em_rx_queue *que;
 	int i;
-	u32 rctl, rxcsum, rfctl;
+	uint32_t rctl, rxcsum;
 
 	INIT_DEBUGOUT("em_initialize_receive_units: begin");
 
@@ -3224,21 +3225,25 @@ em_initialize_receive_unit(if_ctx_t ctx)
 	}
 	E1000_WRITE_REG(hw, E1000_RDTR, adapter->rx_int_delay.value);
 
-	/* Use extended rx descriptor formats */
-	rfctl = E1000_READ_REG(hw, E1000_RFCTL);
-	rfctl |= E1000_RFCTL_EXTEN;
-	/*
-	 * When using MSI-X interrupts we need to throttle
-	 * using the EITR register (82574 only)
-	 */
-	if (hw->mac.type == e1000_82574) {
-		for (int i = 0; i < 4; i++)
-			E1000_WRITE_REG(hw, E1000_EITR_82574(i),
-			    DEFAULT_ITR);
-		/* Disable accelerated acknowledge */
-		rfctl |= E1000_RFCTL_ACK_DIS;
+	if (hw->mac.type >= em_mac_min) {
+		uint32_t rfctl;
+		/* Use extended rx descriptor formats */
+		rfctl = E1000_READ_REG(hw, E1000_RFCTL);
+		rfctl |= E1000_RFCTL_EXTEN;
+
+		/*
+		 * When using MSI-X interrupts we need to throttle
+		 * using the EITR register (82574 only)
+		 */
+		if (hw->mac.type == e1000_82574) {
+			for (int i = 0; i < 4; i++)
+				E1000_WRITE_REG(hw, E1000_EITR_82574(i),
+				    DEFAULT_ITR);
+			/* Disable accelerated acknowledge */
+			rfctl |= E1000_RFCTL_ACK_DIS;
+		}
+		E1000_WRITE_REG(hw, E1000_RFCTL, rfctl);
 	}
-	E1000_WRITE_REG(hw, E1000_RFCTL, rfctl);
 
 	rxcsum = E1000_READ_REG(hw, E1000_RXCSUM);
 	if (if_getcapenable(ifp) & IFCAP_RXCSUM &&
@@ -3323,24 +3328,17 @@ em_initialize_receive_unit(if_ctx_t ctx)
 		u32 psize, srrctl = 0;
 
 		if (if_getmtu(ifp) > ETHERMTU) {
-			/* Set maximum packet len */
-			if (adapter->rx_mbuf_sz <= 4096) {
-				srrctl |= 4096 >> E1000_SRRCTL_BSIZEPKT_SHIFT;
-				rctl |= E1000_RCTL_SZ_4096 | E1000_RCTL_BSEX;
-			} else if (adapter->rx_mbuf_sz > 4096) {
-				srrctl |= 8192 >> E1000_SRRCTL_BSIZEPKT_SHIFT;
-				rctl |= E1000_RCTL_SZ_8192 | E1000_RCTL_BSEX;
-			}
 			psize = scctx->isc_max_frame_size;
 			/* are we on a vlan? */
 			if (ifp->if_vlantrunk != NULL)
 				psize += VLAN_TAG_SIZE;
 			E1000_WRITE_REG(hw, E1000_RLPML, psize);
-		} else {
-			srrctl |= 2048 >> E1000_SRRCTL_BSIZEPKT_SHIFT;
-			rctl |= E1000_RCTL_SZ_2048;
 		}
 
+		/* Set maximum packet buffer len */
+		srrctl |= (adapter->rx_mbuf_sz + BSIZEPKT_ROUNDUP) >>
+		    E1000_SRRCTL_BSIZEPKT_SHIFT;
+
 		/*
 		 * If TX flow control is disabled and there's >1 queue defined,
 		 * enable DROP.
@@ -3391,17 +3389,29 @@ em_initialize_receive_unit(if_ctx_t ctx)
 	/* Make sure VLAN Filters are off */
 	rctl &= ~E1000_RCTL_VFE;
 
+	/* Set up packet buffer size, overridden by per queue srrctl on igb */
 	if (hw->mac.type < igb_mac_min) {
-		if (adapter->rx_mbuf_sz == MCLBYTES)
-			rctl |= E1000_RCTL_SZ_2048;
-		else if (adapter->rx_mbuf_sz == MJUMPAGESIZE)
+		if (adapter->rx_mbuf_sz > 2048 && adapter->rx_mbuf_sz <= 4096)
 			rctl |= E1000_RCTL_SZ_4096 | E1000_RCTL_BSEX;
-		else if (adapter->rx_mbuf_sz > MJUMPAGESIZE)
+		else if (adapter->rx_mbuf_sz > 4096 && adapter->rx_mbuf_sz <= 8192)
 			rctl |= E1000_RCTL_SZ_8192 | E1000_RCTL_BSEX;
+		else if (adapter->rx_mbuf_sz > 8192)
+			rctl |= E1000_RCTL_SZ_16384 | E1000_RCTL_BSEX;
+		else {
+			rctl |= E1000_RCTL_SZ_2048;
+			rctl &= ~E1000_RCTL_BSEX;
+		}
+	} else
+		rctl |= E1000_RCTL_SZ_2048;
 
-		/* ensure we clear use DTYPE of 00 here */
-		rctl &= ~0x00000C00;
-	}
+	/*
+	 * rctl bits 11:10 are as follows
+	 * lem: reserved
+	 * em: DTYPE
+	 * igb: reserved
+	 * and should be 00 on all of the above
+	 */
+	rctl &= ~0x00000C00;
 
 	/* Write out the settings */
 	E1000_WRITE_REG(hw, E1000_RCTL, rctl);