Re: [PATCH net-next 07/12] net: dsa: rzn1-a5psw: add statistics support

[Vladimir Oltean]

On Thu, Apr 14, 2022 at 02:22:45PM +0200, Clément Léger wrote:
> Add per-port statistics. This support requries to add a stat lock since
> statistics are stored in two 32 bits registers, the hi part one being
> global and latched when accessing the lo part.
> 
> Signed-off-by: Clément Léger <clement.leger@xxxxxxxxxxx>
> ---

I think for new drivers Jakub will also want to see the more specific
and less free-form get_stats64, get_eth_mac_stats, get_eth_phy_stats,
get_eth_ctrl_stats ops implemented. Your counters should map nicely over
these.

>  drivers/net/dsa/rzn1_a5psw.c | 101 +++++++++++++++++++++++++++++++++++
>  drivers/net/dsa/rzn1_a5psw.h |   2 +
>  2 files changed, 103 insertions(+)
> 
> diff --git a/drivers/net/dsa/rzn1_a5psw.c b/drivers/net/dsa/rzn1_a5psw.c
> index 5bee999f7050..7ab7d9054427 100644
> --- a/drivers/net/dsa/rzn1_a5psw.c
> +++ b/drivers/net/dsa/rzn1_a5psw.c
> @@ -16,6 +16,59 @@
>  
>  #include "rzn1_a5psw.h"
>  
> +struct a5psw_stats {
> +	u16 offset;
> +	const char *name;
> +};
> +
> +#define STAT_DESC(_offset, _name) {.offset = _offset, .name = _name}
> +
> +static const struct a5psw_stats a5psw_stats[] = {
> +	STAT_DESC(0x868, "aFrameTransmitted"),
> +	STAT_DESC(0x86C, "aFrameReceived"),
> +	STAT_DESC(0x870, "aFrameCheckSequenceErrors"),
> +	STAT_DESC(0x874, "aAlignmentErrors"),
> +	STAT_DESC(0x878, "aOctetsTransmitted"),
> +	STAT_DESC(0x87C, "aOctetsReceived"),
> +	STAT_DESC(0x880, "aTxPAUSEMACCtrlFrames"),
> +	STAT_DESC(0x884, "aRxPAUSEMACCtrlFrames"),

What does the "a" stand for?

> +	/* If */
> +	STAT_DESC(0x888, "ifInErrors"),
> +	STAT_DESC(0x88C, "ifOutErrors"),
> +	STAT_DESC(0x890, "ifInUcastPkts"),
> +	STAT_DESC(0x894, "ifInMulticastPkts"),
> +	STAT_DESC(0x898, "ifInBroadcastPkts"),
> +	STAT_DESC(0x89C, "ifOutDiscards"),
> +	STAT_DESC(0x8A0, "ifOutUcastPkts"),
> +	STAT_DESC(0x8A4, "ifOutMulticastPkts"),
> +	STAT_DESC(0x8A8, "ifOutBroadcastPkts"),
> +	/* Ether */
> +	STAT_DESC(0x8AC, "etherStatsDropEvents"),
> +	STAT_DESC(0x8B0, "etherStatsOctets"),
> +	STAT_DESC(0x8B4, "etherStatsPkts"),
> +	STAT_DESC(0x8B8, "etherStatsUndersizePkts"),
> +	STAT_DESC(0x8BC, "etherStatsetherStatsOversizePktsDropEvents"),

"etherStats" is duplicated here.

> +	STAT_DESC(0x8C0, "etherStatsPkts64Octets"),
> +	STAT_DESC(0x8C4, "etherStatsPkts65to127Octets"),
> +	STAT_DESC(0x8C8, "etherStatsPkts128to255Octets"),
> +	STAT_DESC(0x8CC, "etherStatsPkts256to511Octets"),
> +	STAT_DESC(0x8D0, "etherStatsPkts512to1023Octets"),
> +	STAT_DESC(0x8D4, "etherStatsPkts1024to1518Octets"),
> +	STAT_DESC(0x8D8, "etherStatsPkts1519toXOctets"),
> +	STAT_DESC(0x8DC, "etherStatsJabbers"),
> +	STAT_DESC(0x8E0, "etherStatsFragments"),
> +
> +	STAT_DESC(0x8E8, "VLANReceived"),
> +	STAT_DESC(0x8EC, "VLANTransmitted"),
> +
> +	STAT_DESC(0x910, "aDeferred"),
> +	STAT_DESC(0x914, "aMultipleCollisions"),
> +	STAT_DESC(0x918, "aSingleCollisions"),
> +	STAT_DESC(0x91C, "aLateCollisions"),
> +	STAT_DESC(0x920, "aExcessiveCollisions"),
> +	STAT_DESC(0x924, "aCarrierSenseErrors"),
> +};
> +
>  static void a5psw_reg_writel(struct a5psw *a5psw, int offset, u32 value)
>  {
>  	writel(value, a5psw->base + offset);
> @@ -316,6 +369,50 @@ static void a5psw_port_fast_age(struct dsa_switch *ds, int port)
>  	a5psw_port_fdb_flush(a5psw, port);
>  }
>  
> +static void a5psw_get_strings(struct dsa_switch *ds, int port, u32 stringset,
> +			      uint8_t *data)
> +{
> +	unsigned int u;
> +
> +	if (stringset != ETH_SS_STATS)
> +		return;
> +
> +	for (u = 0; u < ARRAY_SIZE(a5psw_stats); u++) {
> +		strncpy(data + u * ETH_GSTRING_LEN, a5psw_stats[u].name,
> +			ETH_GSTRING_LEN);
> +	}
> +}
> +
> +static void a5psw_get_ethtool_stats(struct dsa_switch *ds, int port,
> +				    uint64_t *data)
> +{
> +	struct a5psw *a5psw = ds->priv;
> +	u32 reg_lo, reg_hi;
> +	unsigned int u;
> +
> +	for (u = 0; u < ARRAY_SIZE(a5psw_stats); u++) {
> +		/* A5PSW_STATS_HIWORD is global and thus, access must be
> +		 * exclusive
> +		 */
> +		spin_lock(&a5psw->stats_lock);
> +		reg_lo = a5psw_reg_readl(a5psw, a5psw_stats[u].offset +
> +					 A5PSW_PORT_OFFSET(port));
> +		/* A5PSW_STATS_HIWORD is latched on stat read */
> +		reg_hi = a5psw_reg_readl(a5psw, A5PSW_STATS_HIWORD);
> +
> +		data[u] = ((u64)reg_hi << 32) | reg_lo;
> +		spin_unlock(&a5psw->stats_lock);
> +	}
> +}
> +
> +static int a5psw_get_sset_count(struct dsa_switch *ds, int port, int sset)
> +{
> +	if (sset != ETH_SS_STATS)
> +		return 0;
> +
> +	return ARRAY_SIZE(a5psw_stats);
> +}
> +
>  static int a5psw_setup(struct dsa_switch *ds)
>  {
>  	struct a5psw *a5psw = ds->priv;
> @@ -395,6 +492,9 @@ const struct dsa_switch_ops a5psw_switch_ops = {
>  	.phylink_mac_link_up = a5psw_phylink_mac_link_up,
>  	.port_change_mtu = a5psw_port_change_mtu,
>  	.port_max_mtu = a5psw_port_max_mtu,
> +	.get_sset_count = a5psw_get_sset_count,
> +	.get_strings = a5psw_get_strings,
> +	.get_ethtool_stats = a5psw_get_ethtool_stats,
>  	.set_ageing_time = a5psw_set_ageing_time,
>  	.port_bridge_join = a5psw_port_bridge_join,
>  	.port_bridge_leave = a5psw_port_bridge_leave,
> @@ -580,6 +680,7 @@ static int a5psw_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>  
>  	a5psw->dev = dev;
> +	spin_lock_init(&a5psw->stats_lock);
>  	spin_lock_init(&a5psw->lk_lock);
>  	spin_lock_init(&a5psw->reg_lock);
>  	a5psw->base = devm_platform_ioremap_resource(pdev, 0);
> diff --git a/drivers/net/dsa/rzn1_a5psw.h b/drivers/net/dsa/rzn1_a5psw.h
> index 2d96a2afbc3a..b34ea549e936 100644
> --- a/drivers/net/dsa/rzn1_a5psw.h
> +++ b/drivers/net/dsa/rzn1_a5psw.h
> @@ -177,6 +177,7 @@
>   * @mdio_freq: MDIO bus frequency requested
>   * @pcs: Array of PCS connected to the switch ports (not for the CPU)
>   * @ds: DSA switch struct
> + * @stats_lock: lock to access statistics (shared HI counter)
>   * @lk_lock: Lock for the lookup table
>   * @reg_lock: Lock for register read-modify-write operation
>   * @flooding_ports: List of ports that should be flooded
> @@ -190,6 +191,7 @@ struct a5psw {
>  	u32 mdio_freq;
>  	struct phylink_pcs *pcs[A5PSW_PORTS_NUM - 1];
>  	struct dsa_switch ds;
> +	spinlock_t stats_lock;
>  	spinlock_t lk_lock;
>  	spinlock_t reg_lock;
>  	u32 flooding_ports;
> -- 
> 2.34.1
>