linux-kernel - [net-next Patch] Octeontx2-af: Broadcast XON on all channels

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Message-ID: <20250820064625.1464361-1-hkelam@marvell.com>
Date: Wed, 20 Aug 2025 12:16:25 +0530
From: Hariprasad Kelam <hkelam@...vell.com>
To: <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC: Hariprasad Kelam <hkelam@...vell.com>,
        Sunil Goutham
	<sgoutham@...vell.com>,
        Linu Cherian <lcherian@...vell.com>,
        Geetha sowjanya
	<gakula@...vell.com>,
        Jerin Jacob <jerinj@...vell.com>,
        Subbaraya Sundeep
	<sbhatta@...vell.com>,
        Andrew Lunn <andrew+netdev@...n.ch>,
        "David S. Miller"
	<davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski
	<kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>
Subject: [net-next Patch] Octeontx2-af: Broadcast XON on all channels

The NIX block receives traffic from multiple channels, including:

MAC block (RPM)
Loopback module (LBK)
CPT block

                     RPM
                      |
                -----------------
       LBK   --|     NIX         |
                -----------------
                     |
                    CPT

Due to a hardware errata,  CN10k and earlier Octeon silicon series,
the hardware may incorrectly assert XOFF on certain channels during
reset. As a workaround, a write operation to the NIX_AF_RX_CHANX_CFG
register can be performed to broadcast XON signals on the affected
channels

Signed-off-by: Hariprasad Kelam <hkelam@...vell.com>
---
 drivers/net/ethernet/marvell/octeontx2/af/rvu.c  |  3 +++
 drivers/net/ethernet/marvell/octeontx2/af/rvu.h  |  1 +
 .../net/ethernet/marvell/octeontx2/af/rvu_nix.c  | 16 ++++++++++++++++
 3 files changed, 20 insertions(+)

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
index c6bb3aaa8e0d..2d78e08f985f 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
@@ -1164,6 +1164,9 @@ static int rvu_setup_hw_resources(struct rvu *rvu)
 	rvu_program_channels(rvu);
 	cgx_start_linkup(rvu);
 
+	rvu_block_bcast_xon(rvu, BLKADDR_NIX0);
+	rvu_block_bcast_xon(rvu, BLKADDR_NIX1);
+
 	err = rvu_mcs_init(rvu);
 	if (err) {
 		dev_err(rvu->dev, "%s: Failed to initialize mcs\n", __func__);
diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu.h b/drivers/net/ethernet/marvell/octeontx2/af/rvu.h
index 7ee1fdeb5295..1692033b46b0 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/rvu.h
+++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu.h
@@ -1017,6 +1017,7 @@ int rvu_nix_mcast_update_mcam_entry(struct rvu *rvu, u16 pcifunc,
 void rvu_nix_flr_free_bpids(struct rvu *rvu, u16 pcifunc);
 int rvu_alloc_cint_qint_mem(struct rvu *rvu, struct rvu_pfvf *pfvf,
 			    int blkaddr, int nixlf);
+void rvu_block_bcast_xon(struct rvu *rvu, int blkaddr);
 /* NPC APIs */
 void rvu_npc_freemem(struct rvu *rvu);
 int rvu_npc_get_pkind(struct rvu *rvu, u16 pf);
diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
index 60db1f616cc8..828316211b24 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
@@ -6616,3 +6616,19 @@ int rvu_mbox_handler_nix_mcast_grp_update(struct rvu *rvu,
 
 	return ret;
 }
+
+/* On CN10k and older series of silicons, hardware may incorrectly
+ * assert XOFF on certain channels. Issue a write on NIX_AF_RX_CHANX_CFG
+ * to broadcacst XON on the same.
+ */
+void rvu_block_bcast_xon(struct rvu *rvu, int blkaddr)
+{
+	struct rvu_block *block = &rvu->hw->block[blkaddr];
+	u64 cfg;
+
+	if (!block->implemented || is_cn20k(rvu->pdev))
+		return;
+
+	cfg = rvu_read64(rvu, blkaddr, NIX_AF_RX_CHANX_CFG(0));
+	rvu_write64(rvu, blkaddr, NIX_AF_RX_CHANX_CFG(0), cfg);
+}
-- 
2.34.1