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* [PATCH net-next] nfp: prevent dropped counter increment during probe
@ 2023-07-12 12:35 Louis Peens
  2023-07-14  4:00 ` patchwork-bot+netdevbpf
  0 siblings, 1 reply; 2+ messages in thread
From: Louis Peens @ 2023-07-12 12:35 UTC (permalink / raw)
  To: David Miller, Jakub Kicinski, Paolo Abeni
  Cc: Simon Horman, Ziyang Chen, netdev, oss-drivers

From: Ziyang Chen <ziyang.chen@corigine.com>

The dev_rx_discards counter will increment by one when an interface is
toggled up and down. The main reason is that the driver first sends a
`NFP_NET_CFG_CTRL_ENABLE` configuration packet to the NIC to perform port
initialisation when an interface is set up. But there is a race between
physical link up and free list queue initialization which may lead to the
configuration packet being discarded.

To address this problem a new bit NFP_NET_CFG_CTRL_FREELIST_EN is added to
perform free list initialisation on the NIC. The FREELIST_EN should be sent
in advance to initialize free list queue. When a port is set to down,
FREELIST_EN should be sent after CTRL_ENABLE to avoid packet discards.

Signed-off-by: Ziyang Chen <ziyang.chen@corigine.com>
Acked-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
---
 .../ethernet/netronome/nfp/nfp_net_common.c   | 54 ++++++++++++++++---
 .../net/ethernet/netronome/nfp/nfp_net_ctrl.h |  1 +
 2 files changed, 48 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
index 6b1fb5708434..f18c791cf698 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
@@ -924,7 +924,7 @@ static void nfp_net_write_mac_addr(struct nfp_net *nn, const u8 *addr)
  */
 static void nfp_net_clear_config_and_disable(struct nfp_net *nn)
 {
-	u32 new_ctrl, update;
+	u32 new_ctrl, new_ctrl_w1, update;
 	unsigned int r;
 	int err;
 
@@ -937,14 +937,29 @@ static void nfp_net_clear_config_and_disable(struct nfp_net *nn)
 	if (nn->cap & NFP_NET_CFG_CTRL_RINGCFG)
 		new_ctrl &= ~NFP_NET_CFG_CTRL_RINGCFG;
 
-	nn_writeq(nn, NFP_NET_CFG_TXRS_ENABLE, 0);
-	nn_writeq(nn, NFP_NET_CFG_RXRS_ENABLE, 0);
+	if (!(nn->cap_w1 & NFP_NET_CFG_CTRL_FREELIST_EN)) {
+		nn_writeq(nn, NFP_NET_CFG_TXRS_ENABLE, 0);
+		nn_writeq(nn, NFP_NET_CFG_RXRS_ENABLE, 0);
+	}
 
 	nn_writel(nn, NFP_NET_CFG_CTRL, new_ctrl);
 	err = nfp_net_reconfig(nn, update);
 	if (err)
 		nn_err(nn, "Could not disable device: %d\n", err);
 
+	if (nn->cap_w1 & NFP_NET_CFG_CTRL_FREELIST_EN) {
+		new_ctrl_w1 = nn->dp.ctrl_w1;
+		new_ctrl_w1 &= ~NFP_NET_CFG_CTRL_FREELIST_EN;
+		nn_writeq(nn, NFP_NET_CFG_TXRS_ENABLE, 0);
+		nn_writeq(nn, NFP_NET_CFG_RXRS_ENABLE, 0);
+
+		nn_writel(nn, NFP_NET_CFG_CTRL_WORD1, new_ctrl_w1);
+		err = nfp_net_reconfig(nn, update);
+		if (err)
+			nn_err(nn, "Could not disable FREELIST_EN: %d\n", err);
+		nn->dp.ctrl_w1 = new_ctrl_w1;
+	}
+
 	for (r = 0; r < nn->dp.num_rx_rings; r++) {
 		nfp_net_rx_ring_reset(&nn->dp.rx_rings[r]);
 		if (nfp_net_has_xsk_pool_slow(&nn->dp, nn->dp.rx_rings[r].idx))
@@ -964,11 +979,12 @@ static void nfp_net_clear_config_and_disable(struct nfp_net *nn)
  */
 static int nfp_net_set_config_and_enable(struct nfp_net *nn)
 {
-	u32 bufsz, new_ctrl, update = 0;
+	u32 bufsz, new_ctrl, new_ctrl_w1, update = 0;
 	unsigned int r;
 	int err;
 
 	new_ctrl = nn->dp.ctrl;
+	new_ctrl_w1 = nn->dp.ctrl_w1;
 
 	if (nn->dp.ctrl & NFP_NET_CFG_CTRL_RSS_ANY) {
 		nfp_net_rss_write_key(nn);
@@ -1001,16 +1017,25 @@ static int nfp_net_set_config_and_enable(struct nfp_net *nn)
 	bufsz = nn->dp.fl_bufsz - nn->dp.rx_dma_off - NFP_NET_RX_BUF_NON_DATA;
 	nn_writel(nn, NFP_NET_CFG_FLBUFSZ, bufsz);
 
-	/* Enable device */
-	new_ctrl |= NFP_NET_CFG_CTRL_ENABLE;
+	/* Enable device
+	 * Step 1: Replace the CTRL_ENABLE by NFP_NET_CFG_CTRL_FREELIST_EN if
+	 * FREELIST_EN exits.
+	 */
+	if (nn->cap_w1 & NFP_NET_CFG_CTRL_FREELIST_EN)
+		new_ctrl_w1 |= NFP_NET_CFG_CTRL_FREELIST_EN;
+	else
+		new_ctrl |= NFP_NET_CFG_CTRL_ENABLE;
 	update |= NFP_NET_CFG_UPDATE_GEN;
 	update |= NFP_NET_CFG_UPDATE_MSIX;
 	update |= NFP_NET_CFG_UPDATE_RING;
 	if (nn->cap & NFP_NET_CFG_CTRL_RINGCFG)
 		new_ctrl |= NFP_NET_CFG_CTRL_RINGCFG;
 
+	/* Step 2: Send the configuration and write the freelist.
+	 * - The freelist only need to be written once.
+	 */
 	nn_writel(nn, NFP_NET_CFG_CTRL, new_ctrl);
-	nn_writel(nn, NFP_NET_CFG_CTRL_WORD1, nn->dp.ctrl_w1);
+	nn_writel(nn, NFP_NET_CFG_CTRL_WORD1, new_ctrl_w1);
 	err = nfp_net_reconfig(nn, update);
 	if (err) {
 		nfp_net_clear_config_and_disable(nn);
@@ -1018,10 +1043,25 @@ static int nfp_net_set_config_and_enable(struct nfp_net *nn)
 	}
 
 	nn->dp.ctrl = new_ctrl;
+	nn->dp.ctrl_w1 = new_ctrl_w1;
 
 	for (r = 0; r < nn->dp.num_rx_rings; r++)
 		nfp_net_rx_ring_fill_freelist(&nn->dp, &nn->dp.rx_rings[r]);
 
+	/* Step 3: Do the NFP_NET_CFG_CTRL_ENABLE. Send the configuration.
+	 */
+	if (nn->cap_w1 & NFP_NET_CFG_CTRL_FREELIST_EN) {
+		new_ctrl |= NFP_NET_CFG_CTRL_ENABLE;
+		nn_writel(nn, NFP_NET_CFG_CTRL, new_ctrl);
+
+		err = nfp_net_reconfig(nn, update);
+		if (err) {
+			nfp_net_clear_config_and_disable(nn);
+			return err;
+		}
+		nn->dp.ctrl = new_ctrl;
+	}
+
 	return 0;
 }
 
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_ctrl.h b/drivers/net/ethernet/netronome/nfp/nfp_net_ctrl.h
index 669b9dccb6a9..3e63f6d6a563 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_ctrl.h
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_ctrl.h
@@ -268,6 +268,7 @@
 #define   NFP_NET_CFG_CTRL_PKT_TYPE	  (0x1 << 0) /* Pkttype offload */
 #define   NFP_NET_CFG_CTRL_IPSEC	  (0x1 << 1) /* IPsec offload */
 #define   NFP_NET_CFG_CTRL_MCAST_FILTER	  (0x1 << 2) /* Multicast Filter */
+#define   NFP_NET_CFG_CTRL_FREELIST_EN	  (0x1 << 6) /* Freelist enable flag bit */
 
 #define NFP_NET_CFG_CAP_WORD1		0x00a4
 
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 2+ messages in thread
* Re: [PATCH net-next] nfp: prevent dropped counter increment during probe
  2023-07-12 12:35 [PATCH net-next] nfp: prevent dropped counter increment during probe Louis Peens
@ 2023-07-14  4:00 ` patchwork-bot+netdevbpf
  0 siblings, 0 replies; 2+ messages in thread
From: patchwork-bot+netdevbpf @ 2023-07-14  4:00 UTC (permalink / raw)
  To: Louis Peens
  Cc: davem, kuba, pabeni, simon.horman, ziyang.chen, netdev, oss-drivers

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Wed, 12 Jul 2023 14:35:51 +0200 you wrote:
> From: Ziyang Chen <ziyang.chen@corigine.com>
> 
> The dev_rx_discards counter will increment by one when an interface is
> toggled up and down. The main reason is that the driver first sends a
> `NFP_NET_CFG_CTRL_ENABLE` configuration packet to the NIC to perform port
> initialisation when an interface is set up. But there is a race between
> physical link up and free list queue initialization which may lead to the
> configuration packet being discarded.
> 
> [...]

Here is the summary with links:
  - [net-next] nfp: prevent dropped counter increment during probe
    https://git.kernel.org/netdev/net-next/c/bec9ce34075e

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html



^ permalink raw reply	[flat|nested] 2+ messages in thread
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2023-07-14  4:00 ` patchwork-bot+netdevbpf

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