[PATCH net-next v2 0/2] net: xilinx: axienet: Add statistics support

[PATCH net-next v2 0/2] net: xilinx: axienet: Add statistics support

[Sean Anderson]

Add support for hardware statistics counters (if they are enabled) in
the AXI Ethernet driver. Unfortunately, the implementation is
complicated a bit since the hardware might only support 32-bit counters.

Changes in v2:
- Switch to a seqlock-based implementation to allow fresher updates
  (rather than always using stale counter values from the previous
  refresh).
- Take stats_lock unconditionally in __axienet_device_reset
- Fix documentation mismatch

Sean Anderson (2):
  net: xilinx: axienet: Report RxRject as rx_dropped
  net: xilinx: axienet: Add statistics support

 drivers/net/ethernet/xilinx/xilinx_axienet.h  |  85 ++++++
 .../net/ethernet/xilinx/xilinx_axienet_main.c | 259 +++++++++++++++++-
 2 files changed, 343 insertions(+), 1 deletion(-)

-- 
2.35.1.1320.gc452695387.dirty

[PATCH net-next v2 1/2] net: xilinx: axienet: Report RxRject as rx_dropped

[Sean Anderson]

The Receive Frame Rejected interrupt is asserted whenever there was a
receive error (bad FCS, bad length, etc.) or whenever the frame was
dropped due to a mismatched address. So this is really a combination of
rx_otherhost_dropped, rx_length_errors, rx_frame_errors, and
rx_crc_errors. Mismatched addresses are common and aren't really errors
at all (much like how fragments are normal on half-duplex links). To
avoid confusion, report these events as rx_dropped. This better
reflects what's going on: the packet was received by the MAC but dropped
before being processed.

Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
---

(no changes since v1)

 drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index ca04c298daa2..b2d7c396e2e3 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -1296,7 +1296,7 @@ static irqreturn_t axienet_eth_irq(int irq, void *_ndev)
 		ndev->stats.rx_missed_errors++;
 
 	if (pending & XAE_INT_RXRJECT_MASK)
-		ndev->stats.rx_frame_errors++;
+		ndev->stats.rx_dropped++;
 
 	axienet_iow(lp, XAE_IS_OFFSET, pending);
 	return IRQ_HANDLED;
-- 
2.35.1.1320.gc452695387.dirty

Re: [PATCH net-next v2 1/2] net: xilinx: axienet: Report RxRject as rx_dropped

[Andrew Lunn]

On Mon, Aug 12, 2024 at 01:41:17PM -0400, Sean Anderson wrote:
> The Receive Frame Rejected interrupt is asserted whenever there was a
> receive error (bad FCS, bad length, etc.) or whenever the frame was
> dropped due to a mismatched address. So this is really a combination of
> rx_otherhost_dropped, rx_length_errors, rx_frame_errors, and
> rx_crc_errors. Mismatched addresses are common and aren't really errors
> at all (much like how fragments are normal on half-duplex links). To
> avoid confusion, report these events as rx_dropped. This better
> reflects what's going on: the packet was received by the MAC but dropped
> before being processed.
> 
> Signed-off-by: Sean Anderson <sean.anderson@linux.dev>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew

[PATCH net-next v2 2/2] net: xilinx: axienet: Add statistics support

[Sean Anderson]

Add support for reading the statistics counters, if they are enabled.
The counters may be 64-bit, but we can't detect this statically as
there's no ability bit for it and the counters are read-only. Therefore,
we assume the counters are 32-bits by default. To ensure we don't miss
an overflow, we read all counters at 13-second intervals. This should be
often enough to ensure the bytes counters don't wrap at 2.5 Gbit/s.

Another complication is that the counters may be reset when the device
is reset (depending on configuration). To ensure the counters persist
across link up/down (including suspend/resume), we maintain our own
versions along with the last counter value we saw. Because we might wait
up to 100 ms for the reset to complete, we use a mutex to protect
writing hw_stats. We can't sleep in ndo_get_stats64, so we use a seqlock
to protect readers.

We don't bother disabling the refresh work when we detect 64-bit
counters. This is because the reset issue requires us to read
hw_stat_base and reset_in_progress anyway, which would still require the
seqcount. And I don't think skipping the task is worth the extra
bookkeeping.

We can't use the byte counters for either get_stats64 or
get_eth_mac_stats. This is because the byte counters include everything
in the frame (destination address to FCS, inclusive). But
rtnl_link_stats64 wants bytes excluding the FCS, and
ethtool_eth_mac_stats wants to exclude the L2 overhead (addresses and
length/type). It might be possible to calculate the byte values Linux
expects based on the frame counters, but I think it is simpler to use
the existing software counters.

Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
---

Changes in v2:
- Switch to a seqlock-based implementation to allow fresher updates
  (rather than always using stale counter values from the previous
  refresh).
- Take stats_lock unconditionally in __axienet_device_reset
- Fix documentation mismatch

 drivers/net/ethernet/xilinx/xilinx_axienet.h  |  85 ++++++
 .../net/ethernet/xilinx/xilinx_axienet_main.c | 257 ++++++++++++++++++
 2 files changed, 342 insertions(+)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet.h b/drivers/net/ethernet/xilinx/xilinx_axienet.h
index 0d5b300107e0..373c56080dde 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet.h
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet.h
@@ -156,6 +156,7 @@
 #define XAE_TPID0_OFFSET	0x00000028 /* VLAN TPID0 register */
 #define XAE_TPID1_OFFSET	0x0000002C /* VLAN TPID1 register */
 #define XAE_PPST_OFFSET		0x00000030 /* PCS PMA Soft Temac Status Reg */
+#define XAE_STATS_OFFSET	0x00000200 /* Statistics counters */
 #define XAE_RCW0_OFFSET		0x00000400 /* Rx Configuration Word 0 */
 #define XAE_RCW1_OFFSET		0x00000404 /* Rx Configuration Word 1 */
 #define XAE_TC_OFFSET		0x00000408 /* Tx Configuration */
@@ -163,6 +164,7 @@
 #define XAE_EMMC_OFFSET		0x00000410 /* EMAC mode configuration */
 #define XAE_PHYC_OFFSET		0x00000414 /* RGMII/SGMII configuration */
 #define XAE_ID_OFFSET		0x000004F8 /* Identification register */
+#define XAE_ABILITY_OFFSET	0x000004FC /* Ability Register offset */
 #define XAE_MDIO_MC_OFFSET	0x00000500 /* MII Management Config */
 #define XAE_MDIO_MCR_OFFSET	0x00000504 /* MII Management Control */
 #define XAE_MDIO_MWD_OFFSET	0x00000508 /* MII Management Write Data */
@@ -283,6 +285,16 @@
 #define XAE_PHYC_SGLINKSPD_100		0x40000000 /* SGMII link 100 Mbit */
 #define XAE_PHYC_SGLINKSPD_1000		0x80000000 /* SGMII link 1000 Mbit */
 
+/* Bit masks for Axi Ethernet ability register */
+#define XAE_ABILITY_PFC			BIT(16)
+#define XAE_ABILITY_FRAME_FILTER	BIT(10)
+#define XAE_ABILITY_HALF_DUPLEX		BIT(9)
+#define XAE_ABILITY_STATS		BIT(8)
+#define XAE_ABILITY_2_5G		BIT(3)
+#define XAE_ABILITY_1G			BIT(2)
+#define XAE_ABILITY_100M		BIT(1)
+#define XAE_ABILITY_10M			BIT(0)
+
 /* Bit masks for Axi Ethernet MDIO interface MC register */
 #define XAE_MDIO_MC_MDIOEN_MASK		0x00000040 /* MII management enable */
 #define XAE_MDIO_MC_CLOCK_DIVIDE_MAX	0x3F	   /* Maximum MDIO divisor */
@@ -331,6 +343,7 @@
 #define XAE_FEATURE_FULL_RX_CSUM	BIT(2)
 #define XAE_FEATURE_FULL_TX_CSUM	BIT(3)
 #define XAE_FEATURE_DMA_64BIT		BIT(4)
+#define XAE_FEATURE_STATS		BIT(5)
 
 #define XAE_NO_CSUM_OFFLOAD		0
 
@@ -344,6 +357,61 @@
 #define XLNX_MII_STD_SELECT_REG		0x11
 #define XLNX_MII_STD_SELECT_SGMII	BIT(0)
 
+/* enum temac_stat - TEMAC statistics counters
+ *
+ * Index of statistics counters within the TEMAC. This must match the
+ * order/offset of hardware registers exactly.
+ */
+enum temac_stat {
+	STAT_RX_BYTES = 0,
+	STAT_TX_BYTES,
+	STAT_UNDERSIZE_FRAMES,
+	STAT_FRAGMENT_FRAMES,
+	STAT_RX_64_BYTE_FRAMES,
+	STAT_RX_65_127_BYTE_FRAMES,
+	STAT_RX_128_255_BYTE_FRAMES,
+	STAT_RX_256_511_BYTE_FRAMES,
+	STAT_RX_512_1023_BYTE_FRAMES,
+	STAT_RX_1024_MAX_BYTE_FRAMES,
+	STAT_RX_OVERSIZE_FRAMES,
+	STAT_TX_64_BYTE_FRAMES,
+	STAT_TX_65_127_BYTE_FRAMES,
+	STAT_TX_128_255_BYTE_FRAMES,
+	STAT_TX_256_511_BYTE_FRAMES,
+	STAT_TX_512_1023_BYTE_FRAMES,
+	STAT_TX_1024_MAX_BYTE_FRAMES,
+	STAT_TX_OVERSIZE_FRAMES,
+	STAT_RX_GOOD_FRAMES,
+	STAT_RX_FCS_ERRORS,
+	STAT_RX_BROADCAST_FRAMES,
+	STAT_RX_MULTICAST_FRAMES,
+	STAT_RX_CONTROL_FRAMES,
+	STAT_RX_LENGTH_ERRORS,
+	STAT_RX_VLAN_FRAMES,
+	STAT_RX_PAUSE_FRAMES,
+	STAT_RX_CONTROL_OPCODE_ERRORS,
+	STAT_TX_GOOD_FRAMES,
+	STAT_TX_BROADCAST_FRAMES,
+	STAT_TX_MULTICAST_FRAMES,
+	STAT_TX_UNDERRUN_ERRORS,
+	STAT_TX_CONTROL_FRAMES,
+	STAT_TX_VLAN_FRAMES,
+	STAT_TX_PAUSE_FRAMES,
+	STAT_TX_SINGLE_COLLISION_FRAMES,
+	STAT_TX_MULTIPLE_COLLISION_FRAMES,
+	STAT_TX_DEFERRED_FRAMES,
+	STAT_TX_LATE_COLLISIONS,
+	STAT_TX_EXCESS_COLLISIONS,
+	STAT_TX_EXCESS_DEFERRAL,
+	STAT_RX_ALIGNMENT_ERRORS,
+	STAT_TX_PFC_FRAMES,
+	STAT_RX_PFC_FRAMES,
+	STAT_USER_DEFINED0,
+	STAT_USER_DEFINED1,
+	STAT_USER_DEFINED2,
+	STAT_COUNT,
+};
+
 /**
  * struct axidma_bd - Axi Dma buffer descriptor layout
  * @next:         MM2S/S2MM Next Descriptor Pointer
@@ -434,6 +502,16 @@ struct skbuf_dma_descriptor {
  * @tx_packets: TX packet count for statistics
  * @tx_bytes:	TX byte count for statistics
  * @tx_stat_sync: Synchronization object for TX stats
+ * @hw_stat_base: Base offset for statistics counters. This may be nonzero if
+ *                the statistics counteres were reset or wrapped around.
+ * @hw_last_counter: Last-seen value of each statistic counter
+ * @reset_in_progress: Set while we are performing a reset and statistics
+ *                     counters may be invalid
+ * @hw_stats_seqcount: Sequence counter for @hw_stat_base, @hw_last_counter,
+ *                     and @reset_in_progress.
+ * @stats_lock: Lock for @hw_stats_seqcount
+ * @stats_work: Work for reading the hardware statistics counters often enough
+ *              to catch overflows.
  * @dma_err_task: Work structure to process Axi DMA errors
  * @tx_irq:	Axidma TX IRQ number
  * @rx_irq:	Axidma RX IRQ number
@@ -505,6 +583,13 @@ struct axienet_local {
 	u64_stats_t tx_bytes;
 	struct u64_stats_sync tx_stat_sync;
 
+	u64 hw_stat_base[STAT_COUNT];
+	u64 hw_last_counter[STAT_COUNT];
+	seqcount_mutex_t hw_stats_seqcount;
+	struct mutex stats_lock;
+	struct delayed_work stats_work;
+	bool reset_in_progress;
+
 	struct work_struct dma_err_task;
 
 	int tx_irq;
diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index b2d7c396e2e3..7bb25a171710 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -519,11 +519,55 @@ static void axienet_setoptions(struct net_device *ndev, u32 options)
 	lp->options |= options;
 }
 
+static u64 axienet_stat(struct axienet_local *lp, enum temac_stat stat)
+{
+	u32 counter;
+
+	if (lp->reset_in_progress)
+		return lp->hw_stat_base[stat];
+
+	counter = axienet_ior(lp, XAE_STATS_OFFSET + stat * 8);
+	return lp->hw_stat_base[stat] + (counter - lp->hw_last_counter[stat]);
+}
+
+static void axienet_stats_update(struct axienet_local *lp, bool reset)
+{
+	enum temac_stat stat;
+
+	write_seqcount_begin(&lp->hw_stats_seqcount);
+	lp->reset_in_progress = reset;
+	for (stat = 0; stat < STAT_COUNT; stat++) {
+		u32 counter = axienet_ior(lp, XAE_STATS_OFFSET + stat * 8);
+
+		lp->hw_stat_base[stat] += counter - lp->hw_last_counter[stat];
+		lp->hw_last_counter[stat] = counter;
+	}
+	write_seqcount_end(&lp->hw_stats_seqcount);
+}
+
+static void axienet_refresh_stats(struct work_struct *work)
+{
+	struct axienet_local *lp = container_of(work, struct axienet_local,
+						stats_work.work);
+
+	mutex_lock(&lp->stats_lock);
+	axienet_stats_update(lp, false);
+	mutex_unlock(&lp->stats_lock);
+
+	/* Just less than 2^32 bytes at 2.5 GBit/s */
+	schedule_delayed_work(&lp->stats_work, 13 * HZ);
+}
+
 static int __axienet_device_reset(struct axienet_local *lp)
 {
 	u32 value;
 	int ret;
 
+	/* Save statistics counters in case they will be reset */
+	guard(mutex)(&lp->stats_lock);
+	if (lp->features & XAE_FEATURE_STATS)
+		axienet_stats_update(lp, true);
+
 	/* Reset Axi DMA. This would reset Axi Ethernet core as well. The reset
 	 * process of Axi DMA takes a while to complete as all pending
 	 * commands/transfers will be flushed or completed during this
@@ -551,6 +595,23 @@ static int __axienet_device_reset(struct axienet_local *lp)
 		return ret;
 	}
 
+	/* Update statistics counters with new values */
+	if (lp->features & XAE_FEATURE_STATS) {
+		enum temac_stat stat;
+
+		write_seqcount_begin(&lp->hw_stats_seqcount);
+		lp->reset_in_progress = false;
+		for (stat = 0; stat < STAT_COUNT; stat++) {
+			u32 counter =
+				axienet_ior(lp, XAE_STATS_OFFSET + stat * 8);
+
+			lp->hw_stat_base[stat] +=
+				lp->hw_last_counter[stat] - counter;
+			lp->hw_last_counter[stat] = counter;
+		}
+		write_seqcount_end(&lp->hw_stats_seqcount);
+	}
+
 	return 0;
 }
 
@@ -1530,6 +1591,9 @@ static int axienet_open(struct net_device *ndev)
 
 	phylink_start(lp->phylink);
 
+	/* Start the statistics refresh work */
+	schedule_delayed_work(&lp->stats_work, 0);
+
 	if (lp->use_dmaengine) {
 		/* Enable interrupts for Axi Ethernet core (if defined) */
 		if (lp->eth_irq > 0) {
@@ -1554,6 +1618,7 @@ static int axienet_open(struct net_device *ndev)
 	if (lp->eth_irq > 0)
 		free_irq(lp->eth_irq, ndev);
 err_phy:
+	cancel_delayed_work_sync(&lp->stats_work);
 	phylink_stop(lp->phylink);
 	phylink_disconnect_phy(lp->phylink);
 	return ret;
@@ -1579,6 +1644,8 @@ static int axienet_stop(struct net_device *ndev)
 		napi_disable(&lp->napi_rx);
 	}
 
+	cancel_delayed_work_sync(&lp->stats_work);
+
 	phylink_stop(lp->phylink);
 	phylink_disconnect_phy(lp->phylink);
 
@@ -1692,6 +1759,35 @@ axienet_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
 		stats->tx_packets = u64_stats_read(&lp->tx_packets);
 		stats->tx_bytes = u64_stats_read(&lp->tx_bytes);
 	} while (u64_stats_fetch_retry(&lp->tx_stat_sync, start));
+
+	if (!(lp->features & XAE_FEATURE_STATS))
+		return;
+
+	do {
+		start = read_seqcount_begin(&lp->hw_stats_seqcount);
+		stats->rx_length_errors =
+			axienet_stat(lp, STAT_RX_LENGTH_ERRORS);
+		stats->rx_crc_errors = axienet_stat(lp, STAT_RX_FCS_ERRORS);
+		stats->rx_frame_errors =
+			axienet_stat(lp, STAT_RX_ALIGNMENT_ERRORS);
+		stats->rx_errors = axienet_stat(lp, STAT_UNDERSIZE_FRAMES) +
+				   axienet_stat(lp, STAT_FRAGMENT_FRAMES) +
+				   stats->rx_length_errors +
+				   stats->rx_crc_errors +
+				   stats->rx_frame_errors;
+		stats->multicast = axienet_stat(lp, STAT_RX_MULTICAST_FRAMES);
+
+		stats->tx_aborted_errors =
+			axienet_stat(lp, STAT_TX_EXCESS_COLLISIONS);
+		stats->tx_fifo_errors =
+			axienet_stat(lp, STAT_TX_UNDERRUN_ERRORS);
+		stats->tx_window_errors =
+			axienet_stat(lp, STAT_TX_LATE_COLLISIONS);
+		stats->tx_errors = axienet_stat(lp, STAT_TX_EXCESS_DEFERRAL) +
+				   stats->tx_aborted_errors +
+				   stats->tx_fifo_errors +
+				   stats->tx_window_errors;
+	} while (read_seqcount_retry(&lp->hw_stats_seqcount, start));
 }
 
 static const struct net_device_ops axienet_netdev_ops = {
@@ -1984,6 +2080,156 @@ static int axienet_ethtools_nway_reset(struct net_device *dev)
 	return phylink_ethtool_nway_reset(lp->phylink);
 }
 
+static void
+axienet_ethtools_get_pause_stats(struct net_device *dev,
+				 struct ethtool_pause_stats *pause_stats)
+{
+	struct axienet_local *lp = netdev_priv(dev);
+	unsigned int start;
+
+	if (!(lp->features & XAE_FEATURE_STATS))
+		return;
+
+	do {
+		start = read_seqcount_begin(&lp->hw_stats_seqcount);
+		pause_stats->tx_pause_frames =
+			axienet_stat(lp, STAT_TX_PAUSE_FRAMES);
+		pause_stats->rx_pause_frames =
+			axienet_stat(lp, STAT_RX_PAUSE_FRAMES);
+	} while (read_seqcount_retry(&lp->hw_stats_seqcount, start));
+}
+
+static void
+axienet_ethtool_get_eth_mac_stats(struct net_device *dev,
+				  struct ethtool_eth_mac_stats *mac_stats)
+{
+	struct axienet_local *lp = netdev_priv(dev);
+	unsigned int start;
+
+	if (!(lp->features & XAE_FEATURE_STATS))
+		return;
+
+	do {
+		start = read_seqcount_begin(&lp->hw_stats_seqcount);
+		mac_stats->FramesTransmittedOK =
+			axienet_stat(lp, STAT_TX_GOOD_FRAMES);
+		mac_stats->SingleCollisionFrames =
+			axienet_stat(lp, STAT_TX_SINGLE_COLLISION_FRAMES);
+		mac_stats->MultipleCollisionFrames =
+			axienet_stat(lp, STAT_TX_MULTIPLE_COLLISION_FRAMES);
+		mac_stats->FramesReceivedOK =
+			axienet_stat(lp, STAT_RX_GOOD_FRAMES);
+		mac_stats->FrameCheckSequenceErrors =
+			axienet_stat(lp, STAT_RX_FCS_ERRORS);
+		mac_stats->AlignmentErrors =
+			axienet_stat(lp, STAT_RX_ALIGNMENT_ERRORS);
+		mac_stats->FramesWithDeferredXmissions =
+			axienet_stat(lp, STAT_TX_DEFERRED_FRAMES);
+		mac_stats->LateCollisions =
+			axienet_stat(lp, STAT_TX_LATE_COLLISIONS);
+		mac_stats->FramesAbortedDueToXSColls =
+			axienet_stat(lp, STAT_TX_EXCESS_COLLISIONS);
+		mac_stats->MulticastFramesXmittedOK =
+			axienet_stat(lp, STAT_TX_MULTICAST_FRAMES);
+		mac_stats->BroadcastFramesXmittedOK =
+			axienet_stat(lp, STAT_TX_BROADCAST_FRAMES);
+		mac_stats->FramesWithExcessiveDeferral =
+			axienet_stat(lp, STAT_TX_EXCESS_DEFERRAL);
+		mac_stats->MulticastFramesReceivedOK =
+			axienet_stat(lp, STAT_RX_MULTICAST_FRAMES);
+		mac_stats->BroadcastFramesReceivedOK =
+			axienet_stat(lp, STAT_RX_BROADCAST_FRAMES);
+		mac_stats->InRangeLengthErrors =
+			axienet_stat(lp, STAT_RX_LENGTH_ERRORS);
+	} while (read_seqcount_retry(&lp->hw_stats_seqcount, start));
+}
+
+static void
+axienet_ethtool_get_eth_ctrl_stats(struct net_device *dev,
+				   struct ethtool_eth_ctrl_stats *ctrl_stats)
+{
+	struct axienet_local *lp = netdev_priv(dev);
+	unsigned int start;
+
+	if (!(lp->features & XAE_FEATURE_STATS))
+		return;
+
+	do {
+		start = read_seqcount_begin(&lp->hw_stats_seqcount);
+		ctrl_stats->MACControlFramesTransmitted =
+			axienet_stat(lp, STAT_TX_CONTROL_FRAMES);
+		ctrl_stats->MACControlFramesReceived =
+			axienet_stat(lp, STAT_RX_CONTROL_FRAMES);
+		ctrl_stats->UnsupportedOpcodesReceived =
+			axienet_stat(lp, STAT_RX_CONTROL_OPCODE_ERRORS);
+	} while (read_seqcount_retry(&lp->hw_stats_seqcount, start));
+}
+
+static const struct ethtool_rmon_hist_range axienet_rmon_ranges[] = {
+	{   64,    64 },
+	{   65,   127 },
+	{  128,   255 },
+	{  256,   511 },
+	{  512,  1023 },
+	{ 1024,  1518 },
+	{ 1519, 16384 },
+	{ },
+};
+
+static void
+axienet_ethtool_get_rmon_stats(struct net_device *dev,
+			       struct ethtool_rmon_stats *rmon_stats,
+			       const struct ethtool_rmon_hist_range **ranges)
+{
+	struct axienet_local *lp = netdev_priv(dev);
+	unsigned int start;
+
+	if (!(lp->features & XAE_FEATURE_STATS))
+		return;
+
+	do {
+		start = read_seqcount_begin(&lp->hw_stats_seqcount);
+		rmon_stats->undersize_pkts =
+			axienet_stat(lp, STAT_UNDERSIZE_FRAMES);
+		rmon_stats->oversize_pkts =
+			axienet_stat(lp, STAT_RX_OVERSIZE_FRAMES);
+		rmon_stats->fragments =
+			axienet_stat(lp, STAT_FRAGMENT_FRAMES);
+
+		rmon_stats->hist[0] =
+			axienet_stat(lp, STAT_RX_64_BYTE_FRAMES);
+		rmon_stats->hist[1] =
+			axienet_stat(lp, STAT_RX_65_127_BYTE_FRAMES);
+		rmon_stats->hist[2] =
+			axienet_stat(lp, STAT_RX_128_255_BYTE_FRAMES);
+		rmon_stats->hist[3] =
+			axienet_stat(lp, STAT_RX_256_511_BYTE_FRAMES);
+		rmon_stats->hist[4] =
+			axienet_stat(lp, STAT_RX_512_1023_BYTE_FRAMES);
+		rmon_stats->hist[5] =
+			axienet_stat(lp, STAT_RX_1024_MAX_BYTE_FRAMES);
+		rmon_stats->hist[6] =
+			rmon_stats->oversize_pkts;
+
+		rmon_stats->hist_tx[0] =
+			axienet_stat(lp, STAT_TX_64_BYTE_FRAMES);
+		rmon_stats->hist_tx[1] =
+			axienet_stat(lp, STAT_TX_65_127_BYTE_FRAMES);
+		rmon_stats->hist_tx[2] =
+			axienet_stat(lp, STAT_TX_128_255_BYTE_FRAMES);
+		rmon_stats->hist_tx[3] =
+			axienet_stat(lp, STAT_TX_256_511_BYTE_FRAMES);
+		rmon_stats->hist_tx[4] =
+			axienet_stat(lp, STAT_TX_512_1023_BYTE_FRAMES);
+		rmon_stats->hist_tx[5] =
+			axienet_stat(lp, STAT_TX_1024_MAX_BYTE_FRAMES);
+		rmon_stats->hist_tx[6] =
+			axienet_stat(lp, STAT_TX_OVERSIZE_FRAMES);
+	} while (read_seqcount_retry(&lp->hw_stats_seqcount, start));
+
+	*ranges = axienet_rmon_ranges;
+}
+
 static const struct ethtool_ops axienet_ethtool_ops = {
 	.supported_coalesce_params = ETHTOOL_COALESCE_MAX_FRAMES |
 				     ETHTOOL_COALESCE_USECS,
@@ -2000,6 +2246,10 @@ static const struct ethtool_ops axienet_ethtool_ops = {
 	.get_link_ksettings = axienet_ethtools_get_link_ksettings,
 	.set_link_ksettings = axienet_ethtools_set_link_ksettings,
 	.nway_reset	= axienet_ethtools_nway_reset,
+	.get_pause_stats = axienet_ethtools_get_pause_stats,
+	.get_eth_mac_stats = axienet_ethtool_get_eth_mac_stats,
+	.get_eth_ctrl_stats = axienet_ethtool_get_eth_ctrl_stats,
+	.get_rmon_stats = axienet_ethtool_get_rmon_stats,
 };
 
 static struct axienet_local *pcs_to_axienet_local(struct phylink_pcs *pcs)
@@ -2268,6 +2518,10 @@ static int axienet_probe(struct platform_device *pdev)
 	u64_stats_init(&lp->rx_stat_sync);
 	u64_stats_init(&lp->tx_stat_sync);
 
+	mutex_init(&lp->stats_lock);
+	seqcount_mutex_init(&lp->hw_stats_seqcount, &lp->stats_lock);
+	INIT_DEFERRABLE_WORK(&lp->stats_work, axienet_refresh_stats);
+
 	lp->axi_clk = devm_clk_get_optional(&pdev->dev, "s_axi_lite_clk");
 	if (!lp->axi_clk) {
 		/* For backward compatibility, if named AXI clock is not present,
@@ -2308,6 +2562,9 @@ static int axienet_probe(struct platform_device *pdev)
 	/* Setup checksum offload, but default to off if not specified */
 	lp->features = 0;
 
+	if (axienet_ior(lp, XAE_ABILITY_OFFSET) & XAE_ABILITY_STATS)
+		lp->features |= XAE_FEATURE_STATS;
+
 	ret = of_property_read_u32(pdev->dev.of_node, "xlnx,txcsum", &value);
 	if (!ret) {
 		switch (value) {
-- 
2.35.1.1320.gc452695387.dirty

Re: [PATCH net-next v2 2/2] net: xilinx: axienet: Add statistics support

[Andrew Lunn]

>  static int __axienet_device_reset(struct axienet_local *lp)
>  {
>  	u32 value;
>  	int ret;
>  
> +	/* Save statistics counters in case they will be reset */
> +	guard(mutex)(&lp->stats_lock);
> +	if (lp->features & XAE_FEATURE_STATS)
> +		axienet_stats_update(lp, true);

My understanding of guard() is that the mutex is held until the
function completes. That is much longer than you need. A
scoped_guard() would be better here, and it makes it clear when the
mutex will be released.

> +
>  	/* Reset Axi DMA. This would reset Axi Ethernet core as well. The reset
>  	 * process of Axi DMA takes a while to complete as all pending
>  	 * commands/transfers will be flushed or completed during this
> @@ -551,6 +595,23 @@ static int __axienet_device_reset(struct axienet_local *lp)
>  		return ret;
>  	}
>  
> +	/* Update statistics counters with new values */
> +	if (lp->features & XAE_FEATURE_STATS) {
> +		enum temac_stat stat;
> +
> +		write_seqcount_begin(&lp->hw_stats_seqcount);
> +		lp->reset_in_progress = false;
> +		for (stat = 0; stat < STAT_COUNT; stat++) {
> +			u32 counter =
> +				axienet_ior(lp, XAE_STATS_OFFSET + stat * 8);
> +
> +			lp->hw_stat_base[stat] +=
> +				lp->hw_last_counter[stat] - counter;
> +			lp->hw_last_counter[stat] = counter;
> +		}
> +		write_seqcount_end(&lp->hw_stats_seqcount);
> +	}
> +
>  	return 0;
>  }
>  

	Andrew

Re: [PATCH net-next v2 2/2] net: xilinx: axienet: Add statistics support

[Sean Anderson]

On 8/12/24 16:22, Andrew Lunn wrote:
>>  static int __axienet_device_reset(struct axienet_local *lp)
>>  {
>>  	u32 value;
>>  	int ret;
>>  
>> +	/* Save statistics counters in case they will be reset */
>> +	guard(mutex)(&lp->stats_lock);
>> +	if (lp->features & XAE_FEATURE_STATS)
>> +		axienet_stats_update(lp, true);
> 
> My understanding of guard() is that the mutex is held until the
> function completes. That is much longer than you need. A
> scoped_guard() would be better here, and it makes it clear when the
> mutex will be released.

We have to hold it until...

>> +
>>  	/* Reset Axi DMA. This would reset Axi Ethernet core as well. The reset
>>  	 * process of Axi DMA takes a while to complete as all pending
>>  	 * commands/transfers will be flushed or completed during this
>> @@ -551,6 +595,23 @@ static int __axienet_device_reset(struct axienet_local *lp)
>>  		return ret;
>>  	}
>>  
>> +	/* Update statistics counters with new values */
>> +	if (lp->features & XAE_FEATURE_STATS) {
>> +		enum temac_stat stat;
>> +
>> +		write_seqcount_begin(&lp->hw_stats_seqcount);
>> +		lp->reset_in_progress = false;
>> +		for (stat = 0; stat < STAT_COUNT; stat++) {
>> +			u32 counter =
>> +				axienet_ior(lp, XAE_STATS_OFFSET + stat * 8);
>> +
>> +			lp->hw_stat_base[stat] +=
>> +				lp->hw_last_counter[stat] - counter;
>> +			lp->hw_last_counter[stat] = counter;
>> +		}
>> +		write_seqcount_end(&lp->hw_stats_seqcount);

...here

Which is effectively the whole function. The main reason why I used guard() was to
simplify the error return cases.

--Sean

>> +	}
>> +
>>  	return 0;
>>  }
>>  
> 
> 	Andrew

Re: [PATCH net-next v2 2/2] net: xilinx: axienet: Add statistics support

[Andrew Lunn]

On Mon, Aug 12, 2024 at 04:25:16PM -0400, Sean Anderson wrote:
> On 8/12/24 16:22, Andrew Lunn wrote:
> >>  static int __axienet_device_reset(struct axienet_local *lp)
> >>  {
> >>  	u32 value;
> >>  	int ret;
> >>  
> >> +	/* Save statistics counters in case they will be reset */
> >> +	guard(mutex)(&lp->stats_lock);
> >> +	if (lp->features & XAE_FEATURE_STATS)
> >> +		axienet_stats_update(lp, true);
> > 
> > My understanding of guard() is that the mutex is held until the
> > function completes. That is much longer than you need. A
> > scoped_guard() would be better here, and it makes it clear when the
> > mutex will be released.
> 
> We have to hold it until...
> 
> >> +
> >>  	/* Reset Axi DMA. This would reset Axi Ethernet core as well. The reset
> >>  	 * process of Axi DMA takes a while to complete as all pending
> >>  	 * commands/transfers will be flushed or completed during this
> >> @@ -551,6 +595,23 @@ static int __axienet_device_reset(struct axienet_local *lp)
> >>  		return ret;
> >>  	}
> >>  
> >> +	/* Update statistics counters with new values */
> >> +	if (lp->features & XAE_FEATURE_STATS) {
> >> +		enum temac_stat stat;
> >> +
> >> +		write_seqcount_begin(&lp->hw_stats_seqcount);
> >> +		lp->reset_in_progress = false;
> >> +		for (stat = 0; stat < STAT_COUNT; stat++) {
> >> +			u32 counter =
> >> +				axienet_ior(lp, XAE_STATS_OFFSET + stat * 8);
> >> +
> >> +			lp->hw_stat_base[stat] +=
> >> +				lp->hw_last_counter[stat] - counter;
> >> +			lp->hw_last_counter[stat] = counter;
> >> +		}
> >> +		write_seqcount_end(&lp->hw_stats_seqcount);
> 
> ...here
> 
> Which is effectively the whole function. The main reason why I used guard() was to
> simplify the error return cases.

This is why i personally don't like guard. It is not clear you
intended the mutex to be held so long, and that this code actually
requires it. An explicit mutex_unlock() here would make your
intentions clear, or a scoped_guard. I can see guard avoiding some
error path bugs, but i suspect it will introduce other problems when
refactoring code and having to make guesses about what actually needs
the mutex.

	    Andrew

Re: [PATCH net-next v2 2/2] net: xilinx: axienet: Add statistics support

[Sean Anderson]

On 8/12/24 17:18, Andrew Lunn wrote:
> On Mon, Aug 12, 2024 at 04:25:16PM -0400, Sean Anderson wrote:
>> On 8/12/24 16:22, Andrew Lunn wrote:
>> >>  static int __axienet_device_reset(struct axienet_local *lp)
>> >>  {
>> >>  	u32 value;
>> >>  	int ret;
>> >>  
>> >> +	/* Save statistics counters in case they will be reset */
>> >> +	guard(mutex)(&lp->stats_lock);
>> >> +	if (lp->features & XAE_FEATURE_STATS)
>> >> +		axienet_stats_update(lp, true);
>> > 
>> > My understanding of guard() is that the mutex is held until the
>> > function completes. That is much longer than you need. A
>> > scoped_guard() would be better here, and it makes it clear when the
>> > mutex will be released.
>> 
>> We have to hold it until...
>> 
>> >> +
>> >>  	/* Reset Axi DMA. This would reset Axi Ethernet core as well. The reset
>> >>  	 * process of Axi DMA takes a while to complete as all pending
>> >>  	 * commands/transfers will be flushed or completed during this
>> >> @@ -551,6 +595,23 @@ static int __axienet_device_reset(struct axienet_local *lp)
>> >>  		return ret;
>> >>  	}
>> >>  
>> >> +	/* Update statistics counters with new values */
>> >> +	if (lp->features & XAE_FEATURE_STATS) {
>> >> +		enum temac_stat stat;
>> >> +
>> >> +		write_seqcount_begin(&lp->hw_stats_seqcount);
>> >> +		lp->reset_in_progress = false;
>> >> +		for (stat = 0; stat < STAT_COUNT; stat++) {
>> >> +			u32 counter =
>> >> +				axienet_ior(lp, XAE_STATS_OFFSET + stat * 8);
>> >> +
>> >> +			lp->hw_stat_base[stat] +=
>> >> +				lp->hw_last_counter[stat] - counter;
>> >> +			lp->hw_last_counter[stat] = counter;
>> >> +		}
>> >> +		write_seqcount_end(&lp->hw_stats_seqcount);
>> 
>> ...here
>> 
>> Which is effectively the whole function. The main reason why I used guard() was to
>> simplify the error return cases.
> 
> This is why i personally don't like guard. It is not clear you
> intended the mutex to be held so long, and that this code actually
> requires it. An explicit mutex_unlock() here would make your
> intentions clear, or a scoped_guard. I can see guard avoiding some
> error path bugs, but i suspect it will introduce other problems when
> refactoring code and having to make guesses about what actually needs
> the mutex.

OK, I will go back to explicit lock/unlock for v3.

--Sean