[PATCH net-next 0/3] net: ethernet: am65-cpsw: Add ethtool standard MAC stats

[PATCH net-next 0/3] net: ethernet: am65-cpsw: Add ethtool standard MAC stats

[Roger Quadros]

Hi,

Gets 'ethtool -S eth0 --groups eth-mac' command to work.

Also set default TX channels to maximum available.

cheers,
-roger

Roger Quadros (3):
  net: ethernet: am65-cpsw: Add standard Ethernet MAC stats to ethtool
  net: ethernet: am65-cpsw: Set default TX channels to maximum
  net: ethernet: am65-cpsw: Error out if Enable TX/RX channel fails

 drivers/net/ethernet/ti/am65-cpsw-ethtool.c | 26 +++++++++++++++
 drivers/net/ethernet/ti/am65-cpsw-nuss.c    | 37 ++++++++++++++++-----
 2 files changed, 55 insertions(+), 8 deletions(-)


base-commit: 89cdf9d556016a54ff6ddd62324aa5ec790c05cc
-- 
2.34.1

[PATCH net-next 1/3] net: ethernet: am65-cpsw: Add standard Ethernet MAC stats to ethtool

[Roger Quadros]

Gets 'ethtool -S eth0 --groups eth-mac' command to work.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
 drivers/net/ethernet/ti/am65-cpsw-ethtool.c | 26 +++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/net/ethernet/ti/am65-cpsw-ethtool.c b/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
index c51e2af91f69..ac7276f0f77a 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
@@ -662,6 +662,31 @@ static void am65_cpsw_get_ethtool_stats(struct net_device *ndev,
 					hw_stats[i].offset);
 }
 
+static void am65_cpsw_get_eth_mac_stats(struct net_device *ndev,
+					struct ethtool_eth_mac_stats *s)
+{
+	struct am65_cpsw_port *port = am65_ndev_to_port(ndev);
+	struct am65_cpsw_stats_regs *stats;
+
+	stats = port->stat_base;
+
+	s->FramesTransmittedOK = readl_relaxed(&stats->tx_good_frames);
+	s->SingleCollisionFrames = readl_relaxed(&stats->tx_single_coll_frames);
+	s->MultipleCollisionFrames = readl_relaxed(&stats->tx_mult_coll_frames);
+	s->FramesReceivedOK = readl_relaxed(&stats->rx_good_frames);
+	s->FrameCheckSequenceErrors = readl_relaxed(&stats->rx_crc_errors);
+	s->AlignmentErrors = readl_relaxed(&stats->rx_align_code_errors);
+	s->OctetsTransmittedOK = readl_relaxed(&stats->tx_octets);
+	s->FramesWithDeferredXmissions = readl_relaxed(&stats->tx_deferred_frames);
+	s->LateCollisions = readl_relaxed(&stats->tx_late_collisions);
+	s->CarrierSenseErrors = readl_relaxed(&stats->tx_carrier_sense_errors);
+	s->OctetsReceivedOK = readl_relaxed(&stats->rx_octets);
+	s->MulticastFramesXmittedOK = readl_relaxed(&stats->tx_multicast_frames);
+	s->BroadcastFramesXmittedOK = readl_relaxed(&stats->tx_broadcast_frames);
+	s->MulticastFramesReceivedOK = readl_relaxed(&stats->rx_multicast_frames);
+	s->BroadcastFramesReceivedOK = readl_relaxed(&stats->rx_broadcast_frames);
+};
+
 static int am65_cpsw_get_ethtool_ts_info(struct net_device *ndev,
 					 struct ethtool_ts_info *info)
 {
@@ -729,6 +754,7 @@ const struct ethtool_ops am65_cpsw_ethtool_ops_slave = {
 	.get_sset_count		= am65_cpsw_get_sset_count,
 	.get_strings		= am65_cpsw_get_strings,
 	.get_ethtool_stats	= am65_cpsw_get_ethtool_stats,
+	.get_eth_mac_stats	= am65_cpsw_get_eth_mac_stats,
 	.get_ts_info		= am65_cpsw_get_ethtool_ts_info,
 	.get_priv_flags		= am65_cpsw_get_ethtool_priv_flags,
 	.set_priv_flags		= am65_cpsw_set_ethtool_priv_flags,
-- 
2.34.1

[PATCH net-next 2/3] net: ethernet: am65-cpsw: Set default TX channels to maximum

[Roger Quadros]

am65-cpsw supports 8 TX hardware queues. Set this as default.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
 drivers/net/ethernet/ti/am65-cpsw-nuss.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index ece9f8df98ae..7c440899c93c 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -136,6 +136,8 @@
 			 NETIF_MSG_IFUP	| NETIF_MSG_PROBE | NETIF_MSG_IFDOWN | \
 			 NETIF_MSG_RX_ERR | NETIF_MSG_TX_ERR)
 
+#define AM65_CPSW_DEFAULT_TX_CHNS	8
+
 static void am65_cpsw_port_set_sl_mac(struct am65_cpsw_port *slave,
 				      const u8 *dev_addr)
 {
@@ -2897,7 +2899,7 @@ static int am65_cpsw_nuss_probe(struct platform_device *pdev)
 
 	common->rx_flow_id_base = -1;
 	init_completion(&common->tdown_complete);
-	common->tx_ch_num = 1;
+	common->tx_ch_num = AM65_CPSW_DEFAULT_TX_CHNS;
 	common->pf_p0_rx_ptype_rrobin = false;
 	common->default_vlan = 1;
 
-- 
2.34.1

[PATCH net-next 3/3] net: ethernet: am65-cpsw: Error out if Enable TX/RX channel fails

[Roger Quadros]

k3_udma_glue_enable_rx/tx_chn returns error code on failure.
Bail out on error while enabling TX/RX channel.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
 drivers/net/ethernet/ti/am65-cpsw-nuss.c | 33 +++++++++++++++++++-----
 1 file changed, 26 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index 7c440899c93c..340f25bf33b1 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -372,7 +372,7 @@ static void am65_cpsw_init_port_emac_ale(struct am65_cpsw_port *port);
 static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
 {
 	struct am65_cpsw_host *host_p = am65_common_get_host(common);
-	int port_idx, i, ret;
+	int port_idx, i, ret, tx;
 	struct sk_buff *skb;
 	u32 val, port_mask;
 
@@ -453,13 +453,22 @@ static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
 		}
 		kmemleak_not_leak(skb);
 	}
-	k3_udma_glue_enable_rx_chn(common->rx_chns.rx_chn);
 
-	for (i = 0; i < common->tx_ch_num; i++) {
-		ret = k3_udma_glue_enable_tx_chn(common->tx_chns[i].tx_chn);
-		if (ret)
-			return ret;
-		napi_enable(&common->tx_chns[i].napi_tx);
+	ret = k3_udma_glue_enable_rx_chn(common->rx_chns.rx_chn);
+	if (ret) {
+		dev_err(common->dev, "couldn't enable rx chn: %d\n", ret);
+		return ret;
+	}
+
+	for (tx = 0; tx < common->tx_ch_num; tx++) {
+		ret = k3_udma_glue_enable_tx_chn(common->tx_chns[tx].tx_chn);
+		if (ret) {
+			dev_err(common->dev, "couldn't enable tx chn %d: %d\n",
+				tx, ret);
+			tx--;
+			goto fail_tx;
+		}
+		napi_enable(&common->tx_chns[tx].napi_tx);
 	}
 
 	napi_enable(&common->napi_rx);
@@ -470,6 +479,16 @@ static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
 
 	dev_dbg(common->dev, "cpsw_nuss started\n");
 	return 0;
+
+fail_tx:
+	while (tx >= 0) {
+		napi_disable(&common->tx_chns[tx].napi_tx);
+		k3_udma_glue_disable_tx_chn(common->tx_chns[tx].tx_chn);
+		tx--;
+	}
+
+	k3_udma_glue_disable_rx_chn(common->rx_chns.rx_chn);
+	return ret;
 }
 
 static void am65_cpsw_nuss_tx_cleanup(void *data, dma_addr_t desc_dma);
-- 
2.34.1

Re: [PATCH net-next 1/3] net: ethernet: am65-cpsw: Add standard Ethernet MAC stats to ethtool

[Andrew Lunn]

On Mon, Nov 13, 2023 at 01:07:06PM +0200, Roger Quadros wrote:
> Gets 'ethtool -S eth0 --groups eth-mac' command to work.
> 
> Signed-off-by: Roger Quadros <rogerq@kernel.org>

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

    Andrew

Re: [PATCH net-next 2/3] net: ethernet: am65-cpsw: Set default TX channels to maximum

[Andrew Lunn]

On Mon, Nov 13, 2023 at 01:07:07PM +0200, Roger Quadros wrote:
> am65-cpsw supports 8 TX hardware queues. Set this as default.
> 
> Signed-off-by: Roger Quadros <rogerq@kernel.org>

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

    Andrew

Re: [PATCH net-next 3/3] net: ethernet: am65-cpsw: Error out if Enable TX/RX channel fails

[Andrew Lunn]

On Mon, Nov 13, 2023 at 01:07:08PM +0200, Roger Quadros wrote:
> k3_udma_glue_enable_rx/tx_chn returns error code on failure.
> Bail out on error while enabling TX/RX channel.
> 
> Signed-off-by: Roger Quadros <rogerq@kernel.org>

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

    Andrew

Re: [PATCH net-next 1/3] net: ethernet: am65-cpsw: Add standard Ethernet MAC stats to ethtool

[Simon Horman]

On Mon, Nov 13, 2023 at 01:07:06PM +0200, Roger Quadros wrote:
> Gets 'ethtool -S eth0 --groups eth-mac' command to work.
> 
> Signed-off-by: Roger Quadros <rogerq@kernel.org>
> ---
>  drivers/net/ethernet/ti/am65-cpsw-ethtool.c | 26 +++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/net/ethernet/ti/am65-cpsw-ethtool.c b/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
> index c51e2af91f69..ac7276f0f77a 100644
> --- a/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
> +++ b/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
> @@ -662,6 +662,31 @@ static void am65_cpsw_get_ethtool_stats(struct net_device *ndev,
>  					hw_stats[i].offset);
>  }
>  
> +static void am65_cpsw_get_eth_mac_stats(struct net_device *ndev,
> +					struct ethtool_eth_mac_stats *s)
> +{
> +	struct am65_cpsw_port *port = am65_ndev_to_port(ndev);
> +	struct am65_cpsw_stats_regs *stats;

Hi Roger,

I think that stats needs an __iomem annotation
to address the issues flagged by Sparse.

drivers/net/ethernet/ti/am65-cpsw-ethtool.c:671:15: warning: incorrect type in assignment (different address spaces)
drivers/net/ethernet/ti/am65-cpsw-ethtool.c:671:15:    expected struct am65_cpsw_stats_regs *stats
drivers/net/ethernet/ti/am65-cpsw-ethtool.c:671:15:    got void [noderef] __iomem *stat_base
drivers/net/ethernet/ti/am65-cpsw-ethtool.c:673:34: warning: incorrect type in argument 1 (different address spaces)
drivers/net/ethernet/ti/am65-cpsw-ethtool.c:673:34:    expected void const volatile [noderef] __iomem *addr
drivers/net/ethernet/ti/am65-cpsw-ethtool.c:673:34:    got unsigned int *
...

> +
> +	stats = port->stat_base;
> +
> +	s->FramesTransmittedOK = readl_relaxed(&stats->tx_good_frames);
> +	s->SingleCollisionFrames = readl_relaxed(&stats->tx_single_coll_frames);
> +	s->MultipleCollisionFrames = readl_relaxed(&stats->tx_mult_coll_frames);
> +	s->FramesReceivedOK = readl_relaxed(&stats->rx_good_frames);
> +	s->FrameCheckSequenceErrors = readl_relaxed(&stats->rx_crc_errors);
> +	s->AlignmentErrors = readl_relaxed(&stats->rx_align_code_errors);
> +	s->OctetsTransmittedOK = readl_relaxed(&stats->tx_octets);
> +	s->FramesWithDeferredXmissions = readl_relaxed(&stats->tx_deferred_frames);
> +	s->LateCollisions = readl_relaxed(&stats->tx_late_collisions);
> +	s->CarrierSenseErrors = readl_relaxed(&stats->tx_carrier_sense_errors);
> +	s->OctetsReceivedOK = readl_relaxed(&stats->rx_octets);
> +	s->MulticastFramesXmittedOK = readl_relaxed(&stats->tx_multicast_frames);
> +	s->BroadcastFramesXmittedOK = readl_relaxed(&stats->tx_broadcast_frames);
> +	s->MulticastFramesReceivedOK = readl_relaxed(&stats->rx_multicast_frames);
> +	s->BroadcastFramesReceivedOK = readl_relaxed(&stats->rx_broadcast_frames);
> +};
> +
>  static int am65_cpsw_get_ethtool_ts_info(struct net_device *ndev,
>  					 struct ethtool_ts_info *info)
>  {

...

Re: [PATCH net-next 1/3] net: ethernet: am65-cpsw: Add standard Ethernet MAC stats to ethtool

[Roger Quadros]

On 13/11/2023 18:42, Simon Horman wrote:
> On Mon, Nov 13, 2023 at 01:07:06PM +0200, Roger Quadros wrote:
>> Gets 'ethtool -S eth0 --groups eth-mac' command to work.
>>
>> Signed-off-by: Roger Quadros <rogerq@kernel.org>
>> ---
>>  drivers/net/ethernet/ti/am65-cpsw-ethtool.c | 26 +++++++++++++++++++++
>>  1 file changed, 26 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/ti/am65-cpsw-ethtool.c b/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
>> index c51e2af91f69..ac7276f0f77a 100644
>> --- a/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
>> +++ b/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
>> @@ -662,6 +662,31 @@ static void am65_cpsw_get_ethtool_stats(struct net_device *ndev,
>>  					hw_stats[i].offset);
>>  }
>>  
>> +static void am65_cpsw_get_eth_mac_stats(struct net_device *ndev,
>> +					struct ethtool_eth_mac_stats *s)
>> +{
>> +	struct am65_cpsw_port *port = am65_ndev_to_port(ndev);
>> +	struct am65_cpsw_stats_regs *stats;
> 
> Hi Roger,
> 
> I think that stats needs an __iomem annotation
> to address the issues flagged by Sparse.
> 
> drivers/net/ethernet/ti/am65-cpsw-ethtool.c:671:15: warning: incorrect type in assignment (different address spaces)
> drivers/net/ethernet/ti/am65-cpsw-ethtool.c:671:15:    expected struct am65_cpsw_stats_regs *stats
> drivers/net/ethernet/ti/am65-cpsw-ethtool.c:671:15:    got void [noderef] __iomem *stat_base
> drivers/net/ethernet/ti/am65-cpsw-ethtool.c:673:34: warning: incorrect type in argument 1 (different address spaces)
> drivers/net/ethernet/ti/am65-cpsw-ethtool.c:673:34:    expected void const volatile [noderef] __iomem *addr
> drivers/net/ethernet/ti/am65-cpsw-ethtool.c:673:34:    got unsigned int *
> ...

Thanks for the catch Simon.
I'll fix it up.

> 
>> +
>> +	stats = port->stat_base;
>> +
>> +	s->FramesTransmittedOK = readl_relaxed(&stats->tx_good_frames);
>> +	s->SingleCollisionFrames = readl_relaxed(&stats->tx_single_coll_frames);
>> +	s->MultipleCollisionFrames = readl_relaxed(&stats->tx_mult_coll_frames);
>> +	s->FramesReceivedOK = readl_relaxed(&stats->rx_good_frames);
>> +	s->FrameCheckSequenceErrors = readl_relaxed(&stats->rx_crc_errors);
>> +	s->AlignmentErrors = readl_relaxed(&stats->rx_align_code_errors);
>> +	s->OctetsTransmittedOK = readl_relaxed(&stats->tx_octets);
>> +	s->FramesWithDeferredXmissions = readl_relaxed(&stats->tx_deferred_frames);
>> +	s->LateCollisions = readl_relaxed(&stats->tx_late_collisions);
>> +	s->CarrierSenseErrors = readl_relaxed(&stats->tx_carrier_sense_errors);
>> +	s->OctetsReceivedOK = readl_relaxed(&stats->rx_octets);
>> +	s->MulticastFramesXmittedOK = readl_relaxed(&stats->tx_multicast_frames);
>> +	s->BroadcastFramesXmittedOK = readl_relaxed(&stats->tx_broadcast_frames);
>> +	s->MulticastFramesReceivedOK = readl_relaxed(&stats->rx_multicast_frames);
>> +	s->BroadcastFramesReceivedOK = readl_relaxed(&stats->rx_broadcast_frames);
>> +};
>> +
>>  static int am65_cpsw_get_ethtool_ts_info(struct net_device *ndev,
>>  					 struct ethtool_ts_info *info)
>>  {
> 
> ...

-- 
cheers,
-roger

Re: [PATCH net-next 3/3] net: ethernet: am65-cpsw: Error out if Enable TX/RX channel fails

[Vladimir Oltean]

On Mon, Nov 13, 2023 at 01:07:08PM +0200, Roger Quadros wrote:
> k3_udma_glue_enable_rx/tx_chn returns error code on failure.
> Bail out on error while enabling TX/RX channel.
> 
> Signed-off-by: Roger Quadros <rogerq@kernel.org>
> ---
>  drivers/net/ethernet/ti/am65-cpsw-nuss.c | 33 +++++++++++++++++++-----
>  1 file changed, 26 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> index 7c440899c93c..340f25bf33b1 100644
> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> @@ -372,7 +372,7 @@ static void am65_cpsw_init_port_emac_ale(struct am65_cpsw_port *port);
>  static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
>  {
>  	struct am65_cpsw_host *host_p = am65_common_get_host(common);
> -	int port_idx, i, ret;
> +	int port_idx, i, ret, tx;
>  	struct sk_buff *skb;
>  	u32 val, port_mask;
>  
> @@ -453,13 +453,22 @@ static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
>  		}
>  		kmemleak_not_leak(skb);
>  	}
> -	k3_udma_glue_enable_rx_chn(common->rx_chns.rx_chn);
>  
> -	for (i = 0; i < common->tx_ch_num; i++) {
> -		ret = k3_udma_glue_enable_tx_chn(common->tx_chns[i].tx_chn);
> -		if (ret)
> -			return ret;

Can you comment on the kmemleak_not_leak(skb) call above, and its
relationship to the pre-existing error handling path in am65_cpsw_nuss_common_open()?
I see that the dev_kfree_skb_any() call is being made from am65_cpsw_nuss_rx_cleanup(),
which is only called from am65_cpsw_nuss_common_stop().

So if there are errors during am65_cpsw_nuss_common_open() and
descriptors have already been added to the RX DMA channel, they will not
be removed either from hardware or from software. How does that work?

Re: [PATCH net-next 2/3] net: ethernet: am65-cpsw: Set default TX channels to maximum

[Vladimir Oltean]

On Mon, Nov 13, 2023 at 01:07:07PM +0200, Roger Quadros wrote:
> am65-cpsw supports 8 TX hardware queues. Set this as default.

Motivation? Drawbacks / reasons why this was not done from the beginning?

Re: [PATCH net-next 3/3] net: ethernet: am65-cpsw: Error out if Enable TX/RX channel fails

[Roger Quadros]

On 14/11/2023 14:07, Vladimir Oltean wrote:
> On Mon, Nov 13, 2023 at 01:07:08PM +0200, Roger Quadros wrote:
>> k3_udma_glue_enable_rx/tx_chn returns error code on failure.
>> Bail out on error while enabling TX/RX channel.
>>
>> Signed-off-by: Roger Quadros <rogerq@kernel.org>
>> ---
>>  drivers/net/ethernet/ti/am65-cpsw-nuss.c | 33 +++++++++++++++++++-----
>>  1 file changed, 26 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
>> index 7c440899c93c..340f25bf33b1 100644
>> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
>> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
>> @@ -372,7 +372,7 @@ static void am65_cpsw_init_port_emac_ale(struct am65_cpsw_port *port);
>>  static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
>>  {
>>  	struct am65_cpsw_host *host_p = am65_common_get_host(common);
>> -	int port_idx, i, ret;
>> +	int port_idx, i, ret, tx;
>>  	struct sk_buff *skb;
>>  	u32 val, port_mask;
>>  
>> @@ -453,13 +453,22 @@ static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
>>  		}
>>  		kmemleak_not_leak(skb);
>>  	}
>> -	k3_udma_glue_enable_rx_chn(common->rx_chns.rx_chn);
>>  
>> -	for (i = 0; i < common->tx_ch_num; i++) {
>> -		ret = k3_udma_glue_enable_tx_chn(common->tx_chns[i].tx_chn);
>> -		if (ret)
>> -			return ret;
> 
> Can you comment on the kmemleak_not_leak(skb) call above, and its
> relationship to the pre-existing error handling path in am65_cpsw_nuss_common_open()?

I am not aware why it was added. It sure looks odd and I'll get rid of it
and add the necessary error handling.

> I see that the dev_kfree_skb_any() call is being made from am65_cpsw_nuss_rx_cleanup(),
> which is only called from am65_cpsw_nuss_common_stop().
> 
> So if there are errors during am65_cpsw_nuss_common_open() and
> descriptors have already been added to the RX DMA channel, they will not
> be removed either from hardware or from software. How does that work?

I believe this is a gap and I will address it in the next revision. Thanks!

-- 
cheers,
-roger

Re: [PATCH net-next 2/3] net: ethernet: am65-cpsw: Set default TX channels to maximum

[Roger Quadros]

On 14/11/2023 14:13, Vladimir Oltean wrote:
> On Mon, Nov 13, 2023 at 01:07:07PM +0200, Roger Quadros wrote:
>> am65-cpsw supports 8 TX hardware queues. Set this as default.
> 
> Motivation? Drawbacks / reasons why this was not done from the beginning?

Motivation was to get the "kselftest -t net/forwarding:ethtool_mm.sh" test to work
without requiring additional manual step of increasing the TX channels.

Another issue is that all network interfaces (can be up to 4 on some devices) have to be
brought down if TX channel count needs to change.

I am not aware why this was not done from the beginning.

-- 
cheers,
-roger