[PATCH net-next v1] mlxbf_gige: add support to display pause frame counters

[PATCH net-next v1] mlxbf_gige: add support to display pause frame counters

[David Thompson]

This patch updates the mlxbf_gige driver to support the
"get_pause_stats()" callback, which enables display of
pause frame counters via "ethtool -I -a oob_net0".

The pause frame counters are only enabled if the "counters_en"
bit is asserted in the LLU general config register. If this bit
is not asserted, reads to these counters return bogus values.
A run-time check is made to return counter values of 0 if
the counters are not actually enabled.

Reviewed-by: Asmaa Mnebhi <asmaa@nvidia.com>
Signed-off-by: David Thompson <davthompson@nvidia.com>
---
 .../mellanox/mlxbf_gige/mlxbf_gige_ethtool.c  | 39 +++++++++++++++++++
 .../mellanox/mlxbf_gige/mlxbf_gige_regs.h     | 30 ++++++++++++++
 2 files changed, 69 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_ethtool.c b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_ethtool.c
index 253d7ad9b809..107acab06b7e 100644
--- a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_ethtool.c
@@ -124,6 +124,44 @@ static void mlxbf_gige_get_pauseparam(struct net_device *netdev,
 	pause->tx_pause = 1;
 }
 
+static bool mlxbf_gige_llu_counters_enabled(struct mlxbf_gige *priv)
+{
+	u32 data;
+
+	if (priv->hw_version == MLXBF_GIGE_VERSION_BF2) {
+		data = readl(priv->llu_base + MLXBF_GIGE_BF2_LLU_GENERAL_CONFIG);
+		if (data & MLXBF_GIGE_BF2_LLU_COUNTERS_EN)
+			return true;
+	} else {
+		data = readl(priv->llu_base + MLXBF_GIGE_BF3_LLU_GENERAL_CONFIG);
+		if (data & MLXBF_GIGE_BF3_LLU_COUNTERS_EN)
+			return true;
+	}
+
+	return false;
+}
+
+static void mlxbf_gige_get_pause_stats(struct net_device *netdev,
+				       struct ethtool_pause_stats *pause_stats)
+{
+	struct mlxbf_gige *priv = netdev_priv(netdev);
+	u64 data_lo, data_hi;
+
+	/* Read LLU counters only if they are enabled */
+	if (mlxbf_gige_llu_counters_enabled(priv)) {
+		data_lo = readl(priv->llu_base + MLXBF_GIGE_TX_PAUSE_CNT_LO);
+		data_hi = readl(priv->llu_base + MLXBF_GIGE_TX_PAUSE_CNT_HI);
+		pause_stats->tx_pause_frames = (data_hi << 32) | data_lo;
+
+		data_lo = readl(priv->llu_base + MLXBF_GIGE_RX_PAUSE_CNT_LO);
+		data_hi = readl(priv->llu_base + MLXBF_GIGE_RX_PAUSE_CNT_HI);
+		pause_stats->rx_pause_frames = (data_hi << 32) | data_lo;
+	} else {
+		pause_stats->tx_pause_frames = 0;
+		pause_stats->rx_pause_frames = 0;
+	}
+}
+
 const struct ethtool_ops mlxbf_gige_ethtool_ops = {
 	.get_link		= ethtool_op_get_link,
 	.get_ringparam		= mlxbf_gige_get_ringparam,
@@ -134,6 +172,7 @@ const struct ethtool_ops mlxbf_gige_ethtool_ops = {
 	.get_ethtool_stats      = mlxbf_gige_get_ethtool_stats,
 	.nway_reset		= phy_ethtool_nway_reset,
 	.get_pauseparam		= mlxbf_gige_get_pauseparam,
+	.get_pause_stats	= mlxbf_gige_get_pause_stats,
 	.get_link_ksettings	= phy_ethtool_get_link_ksettings,
 	.set_link_ksettings	= phy_ethtool_set_link_ksettings,
 };
diff --git a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_regs.h b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_regs.h
index cd0973229c9b..98a8681c21b9 100644
--- a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_regs.h
+++ b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_regs.h
@@ -99,4 +99,34 @@
 #define MLXBF_GIGE_100M_IPG_SIZE                      119
 #define MLXBF_GIGE_10M_IPG_SIZE                       1199
 
+/* Offsets into OOB LLU block for pause frame counters */
+#define MLXBF_GIGE_BF2_TX_PAUSE_CNT_HI                0x33d8
+#define MLXBF_GIGE_BF2_TX_PAUSE_CNT_LO                0x33dc
+#define MLXBF_GIGE_BF2_RX_PAUSE_CNT_HI                0x3210
+#define MLXBF_GIGE_BF2_RX_PAUSE_CNT_LO                0x3214
+
+#define MLXBF_GIGE_BF3_TX_PAUSE_CNT_HI                0x3a88
+#define MLXBF_GIGE_BF3_TX_PAUSE_CNT_LO                0x3a8c
+#define MLXBF_GIGE_BF3_RX_PAUSE_CNT_HI                0x38c0
+#define MLXBF_GIGE_BF3_RX_PAUSE_CNT_LO                0x38c4
+
+#define MLXBF_GIGE_TX_PAUSE_CNT_HI ((priv->hw_version == MLXBF_GIGE_VERSION_BF2) ? \
+				    MLXBF_GIGE_BF2_TX_PAUSE_CNT_HI :    \
+				    MLXBF_GIGE_BF3_TX_PAUSE_CNT_HI)
+#define MLXBF_GIGE_TX_PAUSE_CNT_LO ((priv->hw_version == MLXBF_GIGE_VERSION_BF2) ? \
+				    MLXBF_GIGE_BF2_TX_PAUSE_CNT_LO : \
+				    MLXBF_GIGE_BF3_TX_PAUSE_CNT_LO)
+#define MLXBF_GIGE_RX_PAUSE_CNT_HI ((priv->hw_version == MLXBF_GIGE_VERSION_BF2) ? \
+				    MLXBF_GIGE_BF2_RX_PAUSE_CNT_HI : \
+				    MLXBF_GIGE_BF3_RX_PAUSE_CNT_HI)
+#define MLXBF_GIGE_RX_PAUSE_CNT_LO ((priv->hw_version == MLXBF_GIGE_VERSION_BF2) ? \
+				    MLXBF_GIGE_BF2_RX_PAUSE_CNT_LO : \
+				    MLXBF_GIGE_BF3_RX_PAUSE_CNT_LO)
+
+#define MLXBF_GIGE_BF2_LLU_GENERAL_CONFIG             0x2110
+#define MLXBF_GIGE_BF3_LLU_GENERAL_CONFIG             0x2030
+
+#define MLXBF_GIGE_BF2_LLU_COUNTERS_EN                BIT(0)
+#define MLXBF_GIGE_BF3_LLU_COUNTERS_EN                BIT(4)
+
 #endif /* !defined(__MLXBF_GIGE_REGS_H__) */
-- 
2.30.1

Re: [PATCH net-next v1] mlxbf_gige: add support to display pause frame counters

[Jakub Kicinski]

On Tue, 5 Mar 2024 10:18:51 -0500 David Thompson wrote:
> +	/* Read LLU counters only if they are enabled */
> +	if (mlxbf_gige_llu_counters_enabled(priv)) {
> +		data_lo = readl(priv->llu_base + MLXBF_GIGE_TX_PAUSE_CNT_LO);
> +		data_hi = readl(priv->llu_base + MLXBF_GIGE_TX_PAUSE_CNT_HI);
> +		pause_stats->tx_pause_frames = (data_hi << 32) | data_lo;
> +
> +		data_lo = readl(priv->llu_base + MLXBF_GIGE_RX_PAUSE_CNT_LO);
> +		data_hi = readl(priv->llu_base + MLXBF_GIGE_RX_PAUSE_CNT_HI);
> +		pause_stats->rx_pause_frames = (data_hi << 32) | data_lo;
> +	} else {
> +		pause_stats->tx_pause_frames = 0;
> +		pause_stats->rx_pause_frames = 0;

Counters are not enabled, meaning we don't know how many frames were
sent? Or pause frames are not enabled, therefore we know it's 0?

If the latter we should add a comment clarifying that, if the former:

 * @get_pause_stats: Report pause frame statistics. Drivers must not zero
 *	statistics which they don't report. The stats structure is initialized
 *	to ETHTOOL_STAT_NOT_SET indicating driver does not report statistics.
-- 
pw-bot: cr

RE: [PATCH net-next v1] mlxbf_gige: add support to display pause frame counters

[David Thompson]

> -----Original Message-----
> From: Jakub Kicinski <kuba@kernel.org>
> Sent: Tuesday, March 5, 2024 1:35 PM
> To: David Thompson <davthompson@nvidia.com>
> Cc: davem@davemloft.net; edumazet@google.com; pabeni@redhat.com;
> netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Asmaa Mnebhi
> <asmaa@nvidia.com>
> Subject: Re: [PATCH net-next v1] mlxbf_gige: add support to display pause frame
> counters
> 
> On Tue, 5 Mar 2024 10:18:51 -0500 David Thompson wrote:
> > +	/* Read LLU counters only if they are enabled */
> > +	if (mlxbf_gige_llu_counters_enabled(priv)) {
> > +		data_lo = readl(priv->llu_base +
> MLXBF_GIGE_TX_PAUSE_CNT_LO);
> > +		data_hi = readl(priv->llu_base +
> MLXBF_GIGE_TX_PAUSE_CNT_HI);
> > +		pause_stats->tx_pause_frames = (data_hi << 32) | data_lo;
> > +
> > +		data_lo = readl(priv->llu_base +
> MLXBF_GIGE_RX_PAUSE_CNT_LO);
> > +		data_hi = readl(priv->llu_base +
> MLXBF_GIGE_RX_PAUSE_CNT_HI);
> > +		pause_stats->rx_pause_frames = (data_hi << 32) | data_lo;
> > +	} else {
> > +		pause_stats->tx_pause_frames = 0;
> > +		pause_stats->rx_pause_frames = 0;
> 
> Counters are not enabled, meaning we don't know how many frames were sent?
> Or pause frames are not enabled, therefore we know it's 0?
> 
> If the latter we should add a comment clarifying that, if the former:
> 
>  * @get_pause_stats: Report pause frame statistics. Drivers must not zero
>  *	statistics which they don't report. The stats structure is initialized
>  *	to ETHTOOL_STAT_NOT_SET indicating driver does not report statistics.
> --
> pw-bot: cr

Hi Jakub, thank you for your comments.

In this case it's the former, so pause frames are enabled we just don't know how
many are sent or received.  I will update the driver patch accordingly and send v2.

Regards, Dave