<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/drivers/net/dsa, branch v6.6-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>net: dsa: sja1105: block FDB accesses that are concurrent with a switch reset</title>
<updated>2023-09-11T07:32:30+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2023-09-08T13:33:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=86899e9e1e29e854b5f6dcc24ba4f75f792c89aa'/>
<id>86899e9e1e29e854b5f6dcc24ba4f75f792c89aa</id>
<content type='text'>
Currently, when we add the first sja1105 port to a bridge with
vlan_filtering 1, then we sometimes see this output:

sja1105 spi2.2: port 4 failed to read back entry for be:79:b4:9e:9e:96 vid 3088: -ENOENT
sja1105 spi2.2: Reset switch and programmed static config. Reason: VLAN filtering
sja1105 spi2.2: port 0 failed to add be:79:b4:9e:9e:96 vid 0 to fdb: -2

It is because sja1105_fdb_add() runs from the dsa_owq which is no longer
serialized with switch resets since it dropped the rtnl_lock() in the
blamed commit.

Either performing the FDB accesses before the reset, or after the reset,
is equally fine, because sja1105_static_fdb_change() backs up those
changes in the static config, but FDB access during reset isn't ok.

Make sja1105_static_config_reload() take the fdb_lock to fix that.

Fixes: 0faf890fc519 ("net: dsa: drop rtnl_lock from dsa_slave_switchdev_event_work")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently, when we add the first sja1105 port to a bridge with
vlan_filtering 1, then we sometimes see this output:

sja1105 spi2.2: port 4 failed to read back entry for be:79:b4:9e:9e:96 vid 3088: -ENOENT
sja1105 spi2.2: Reset switch and programmed static config. Reason: VLAN filtering
sja1105 spi2.2: port 0 failed to add be:79:b4:9e:9e:96 vid 0 to fdb: -2

It is because sja1105_fdb_add() runs from the dsa_owq which is no longer
serialized with switch resets since it dropped the rtnl_lock() in the
blamed commit.

Either performing the FDB accesses before the reset, or after the reset,
is equally fine, because sja1105_static_fdb_change() backs up those
changes in the static config, but FDB access during reset isn't ok.

Make sja1105_static_config_reload() take the fdb_lock to fix that.

Fixes: 0faf890fc519 ("net: dsa: drop rtnl_lock from dsa_slave_switchdev_event_work")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: dsa: sja1105: serialize sja1105_port_mcast_flood() with other FDB accesses</title>
<updated>2023-09-11T07:32:30+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2023-09-08T13:33:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ea32690daf4fa525dc5a4d164bd00ed8c756e1c6'/>
<id>ea32690daf4fa525dc5a4d164bd00ed8c756e1c6</id>
<content type='text'>
sja1105_fdb_add() runs from the dsa_owq, and sja1105_port_mcast_flood()
runs from switchdev_deferred_process_work(). Prior to the blamed commit,
they used to be indirectly serialized through the rtnl_lock(), which
no longer holds true because dsa_owq dropped that.

So, it is now possible that we traverse the static config BLK_IDX_L2_LOOKUP
elements concurrently compared to when we change them, in
sja1105_static_fdb_change(). That is not ideal, since it might result in
data corruption.

Introduce a mutex which serializes accesses to the hardware FDB and to
the static config elements for the L2 Address Lookup table.

I can't find a good reason to add locking around sja1105_fdb_dump().
I'll add it later if needed.

Fixes: 0faf890fc519 ("net: dsa: drop rtnl_lock from dsa_slave_switchdev_event_work")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
sja1105_fdb_add() runs from the dsa_owq, and sja1105_port_mcast_flood()
runs from switchdev_deferred_process_work(). Prior to the blamed commit,
they used to be indirectly serialized through the rtnl_lock(), which
no longer holds true because dsa_owq dropped that.

So, it is now possible that we traverse the static config BLK_IDX_L2_LOOKUP
elements concurrently compared to when we change them, in
sja1105_static_fdb_change(). That is not ideal, since it might result in
data corruption.

Introduce a mutex which serializes accesses to the hardware FDB and to
the static config elements for the L2 Address Lookup table.

I can't find a good reason to add locking around sja1105_fdb_dump().
I'll add it later if needed.

Fixes: 0faf890fc519 ("net: dsa: drop rtnl_lock from dsa_slave_switchdev_event_work")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: dsa: sja1105: fix multicast forwarding working only for last added mdb entry</title>
<updated>2023-09-11T07:32:30+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2023-09-08T13:33:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7cef293b9a634a05fcce9e1df4aee3aeed023345'/>
<id>7cef293b9a634a05fcce9e1df4aee3aeed023345</id>
<content type='text'>
The commit cited in Fixes: did 2 things: it refactored the read-back
polling from sja1105_dynamic_config_read() into a new function,
sja1105_dynamic_config_wait_complete(), and it called that from
sja1105_dynamic_config_write() too.

What is problematic is the refactoring.

The refactored code from sja1105_dynamic_config_poll_valid() works like
the previous one, but the problem is that it uses another packed_buf[]
SPI buffer, and there was code at the end of sja1105_dynamic_config_read()
which was relying on the read-back packed_buf[]:

	/* Don't dereference possibly NULL pointer - maybe caller
	 * only wanted to see whether the entry existed or not.
	 */
	if (entry)
		ops-&gt;entry_packing(packed_buf, entry, UNPACK);

After the change, the packed_buf[] that this code sees is no longer the
entry read back from hardware, but the original entry that the caller
passed to the sja1105_dynamic_config_read(), packed into this buffer.

This difference is the most notable with the SJA1105_SEARCH uses from
sja1105pqrs_fdb_add() - used for both fdb and mdb. There, we have logic
added by commit 728db843df88 ("net: dsa: sja1105: ignore the FDB entry
for unknown multicast when adding a new address") to figure out whether
the address we're trying to add matches on any existing hardware entry,
with the exception of the catch-all multicast address.

That logic was broken, because with sja1105_dynamic_config_read() not
working properly, it doesn't return us the entry read back from
hardware, but the entry that we passed to it. And, since for multicast,
a match will always exist, it will tell us that any mdb entry already
exists at index=0 L2 Address Lookup table. It is index=0 because the
caller doesn't know the index - it wants to find it out, and
sja1105_dynamic_config_read() does:

	if (index &lt; 0) { // SJA1105_SEARCH
		/* Avoid copying a signed negative number to an u64 */
		cmd.index = 0; // &lt;- this
		cmd.search = true;
	} else {
		cmd.index = index;
		cmd.search = false;
	}

So, to the caller of sja1105_dynamic_config_read(), the returned info
looks entirely legit, and it will add all mdb entries to FDB index 0.
There, they will always overwrite each other (not to mention,
potentially they can also overwrite a pre-existing bridge fdb entry),
and the user-visible impact will be that only the last mdb entry will be
forwarded as it should. The others won't (will be flooded or dropped,
depending on the egress flood settings).

Fixing is a bit more complicated, and involves either passing the same
packed_buf[] to sja1105_dynamic_config_wait_complete(), or moving all
the extra processing on the packed_buf[] to
sja1105_dynamic_config_wait_complete(). I've opted for the latter,
because it makes sja1105_dynamic_config_wait_complete() a bit more
self-contained.

Fixes: df405910ab9f ("net: dsa: sja1105: wait for dynamic config command completion on writes too")
Reported-by: Yanan Yang &lt;yanan.yang@nxp.com&gt;
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The commit cited in Fixes: did 2 things: it refactored the read-back
polling from sja1105_dynamic_config_read() into a new function,
sja1105_dynamic_config_wait_complete(), and it called that from
sja1105_dynamic_config_write() too.

What is problematic is the refactoring.

The refactored code from sja1105_dynamic_config_poll_valid() works like
the previous one, but the problem is that it uses another packed_buf[]
SPI buffer, and there was code at the end of sja1105_dynamic_config_read()
which was relying on the read-back packed_buf[]:

	/* Don't dereference possibly NULL pointer - maybe caller
	 * only wanted to see whether the entry existed or not.
	 */
	if (entry)
		ops-&gt;entry_packing(packed_buf, entry, UNPACK);

After the change, the packed_buf[] that this code sees is no longer the
entry read back from hardware, but the original entry that the caller
passed to the sja1105_dynamic_config_read(), packed into this buffer.

This difference is the most notable with the SJA1105_SEARCH uses from
sja1105pqrs_fdb_add() - used for both fdb and mdb. There, we have logic
added by commit 728db843df88 ("net: dsa: sja1105: ignore the FDB entry
for unknown multicast when adding a new address") to figure out whether
the address we're trying to add matches on any existing hardware entry,
with the exception of the catch-all multicast address.

That logic was broken, because with sja1105_dynamic_config_read() not
working properly, it doesn't return us the entry read back from
hardware, but the entry that we passed to it. And, since for multicast,
a match will always exist, it will tell us that any mdb entry already
exists at index=0 L2 Address Lookup table. It is index=0 because the
caller doesn't know the index - it wants to find it out, and
sja1105_dynamic_config_read() does:

	if (index &lt; 0) { // SJA1105_SEARCH
		/* Avoid copying a signed negative number to an u64 */
		cmd.index = 0; // &lt;- this
		cmd.search = true;
	} else {
		cmd.index = index;
		cmd.search = false;
	}

So, to the caller of sja1105_dynamic_config_read(), the returned info
looks entirely legit, and it will add all mdb entries to FDB index 0.
There, they will always overwrite each other (not to mention,
potentially they can also overwrite a pre-existing bridge fdb entry),
and the user-visible impact will be that only the last mdb entry will be
forwarded as it should. The others won't (will be flooded or dropped,
depending on the egress flood settings).

Fixing is a bit more complicated, and involves either passing the same
packed_buf[] to sja1105_dynamic_config_wait_complete(), or moving all
the extra processing on the packed_buf[] to
sja1105_dynamic_config_wait_complete(). I've opted for the latter,
because it makes sja1105_dynamic_config_wait_complete() a bit more
self-contained.

Fixes: df405910ab9f ("net: dsa: sja1105: wait for dynamic config command completion on writes too")
Reported-by: Yanan Yang &lt;yanan.yang@nxp.com&gt;
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: dsa: sja1105: propagate exact error code from sja1105_dynamic_config_poll_valid()</title>
<updated>2023-09-11T07:32:30+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2023-09-08T13:33:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c956798062b5a308db96e75157747291197f0378'/>
<id>c956798062b5a308db96e75157747291197f0378</id>
<content type='text'>
Currently, sja1105_dynamic_config_wait_complete() returns either 0 or
-ETIMEDOUT, because it just looks at the read_poll_timeout() return code.

There will be future changes which move some more checks to
sja1105_dynamic_config_poll_valid(). It is important that we propagate
their exact return code (-ENOENT, -EINVAL), because callers of
sja1105_dynamic_config_read() depend on them.

Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently, sja1105_dynamic_config_wait_complete() returns either 0 or
-ETIMEDOUT, because it just looks at the read_poll_timeout() return code.

There will be future changes which move some more checks to
sja1105_dynamic_config_poll_valid(). It is important that we propagate
their exact return code (-ENOENT, -EINVAL), because callers of
sja1105_dynamic_config_read() depend on them.

Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: dsa: sja1105: hide all multicast addresses from "bridge fdb show"</title>
<updated>2023-09-11T07:32:30+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2023-09-08T13:33:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=02c652f5465011126152bbd93b6a582a1d0c32f1'/>
<id>02c652f5465011126152bbd93b6a582a1d0c32f1</id>
<content type='text'>
Commit 4d9423549501 ("net: dsa: sja1105: offload bridge port flags to
device") has partially hidden some multicast entries from showing up in
the "bridge fdb show" output, but it wasn't enough. Addresses which are
added through "bridge mdb add" still show up. Hide them all.

Fixes: 291d1e72b756 ("net: dsa: sja1105: Add support for FDB and MDB management")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 4d9423549501 ("net: dsa: sja1105: offload bridge port flags to
device") has partially hidden some multicast entries from showing up in
the "bridge fdb show" output, but it wasn't enough. Addresses which are
added through "bridge mdb add" still show up. Hide them all.

Fixes: 291d1e72b756 ("net: dsa: sja1105: Add support for FDB and MDB management")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: phy: Provide Module 4 KSZ9477 errata (DS80000754C)</title>
<updated>2023-09-07T03:49:04+00:00</updated>
<author>
<name>Lukasz Majewski</name>
<email>lukma@denx.de</email>
</author>
<published>2023-09-05T09:33:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=08c6d8bae48c2c28f7017d7b61b5d5a1518ceb39'/>
<id>08c6d8bae48c2c28f7017d7b61b5d5a1518ceb39</id>
<content type='text'>
The KSZ9477 errata points out (in 'Module 4') the link up/down problems
when EEE (Energy Efficient Ethernet) is enabled in the device to which
the KSZ9477 tries to auto negotiate.

The suggested workaround is to clear advertisement of EEE for PHYs in
this chip driver.

To avoid regressions with other switch ICs the new MICREL_NO_EEE flag
has been introduced.

Moreover, the in-register disablement of MMD_DEVICE_ID_EEE_ADV.MMD_EEE_ADV
MMD register is removed, as this code is both; now executed too late
(after previous rework of the PHY and DSA for KSZ switches) and not
required as setting all members of eee_broken_modes bit field prevents
the KSZ9477 from advertising EEE.

Fixes: 69d3b36ca045 ("net: dsa: microchip: enable EEE support") # for KSZ9477
Signed-off-by: Lukasz Majewski &lt;lukma@denx.de&gt;
Tested-by: Oleksij Rempel &lt;o.rempel@pengutronix.de&gt; # Confirmed disabled EEE with oscilloscope.
Reviewed-by: Oleksij Rempel &lt;o.rempel@pengutronix.de&gt;
Reviewed-by: Florian Fainelli &lt;florian.fainelli@broadcom.com&gt;
Link: https://lore.kernel.org/r/20230905093315.784052-1-lukma@denx.de
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The KSZ9477 errata points out (in 'Module 4') the link up/down problems
when EEE (Energy Efficient Ethernet) is enabled in the device to which
the KSZ9477 tries to auto negotiate.

The suggested workaround is to clear advertisement of EEE for PHYs in
this chip driver.

To avoid regressions with other switch ICs the new MICREL_NO_EEE flag
has been introduced.

Moreover, the in-register disablement of MMD_DEVICE_ID_EEE_ADV.MMD_EEE_ADV
MMD register is removed, as this code is both; now executed too late
(after previous rework of the PHY and DSA for KSZ switches) and not
required as setting all members of eee_broken_modes bit field prevents
the KSZ9477 from advertising EEE.

Fixes: 69d3b36ca045 ("net: dsa: microchip: enable EEE support") # for KSZ9477
Signed-off-by: Lukasz Majewski &lt;lukma@denx.de&gt;
Tested-by: Oleksij Rempel &lt;o.rempel@pengutronix.de&gt; # Confirmed disabled EEE with oscilloscope.
Reviewed-by: Oleksij Rempel &lt;o.rempel@pengutronix.de&gt;
Reviewed-by: Florian Fainelli &lt;florian.fainelli@broadcom.com&gt;
Link: https://lore.kernel.org/r/20230905093315.784052-1-lukma@denx.de
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: dsa: sja1105: complete tc-cbs offload support on SJA1110</title>
<updated>2023-09-06T05:23:05+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2023-09-05T21:53:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=180a7419fe4adc8d9c8e0ef0fd17bcdd0cf78acd'/>
<id>180a7419fe4adc8d9c8e0ef0fd17bcdd0cf78acd</id>
<content type='text'>
The blamed commit left this delta behind:

  struct sja1105_cbs_entry {
 -	u64 port;
 -	u64 prio;
 +	u64 port; /* Not used for SJA1110 */
 +	u64 prio; /* Not used for SJA1110 */
  	u64 credit_hi;
  	u64 credit_lo;
  	u64 send_slope;
  	u64 idle_slope;
  };

but did not actually implement tc-cbs offload fully for the new switch.
The offload is accepted, but it doesn't work.

The difference compared to earlier switch generations is that now, the
table of CBS shapers is sparse, because there are many more shapers, so
the mapping between a {port, prio} and a table index is static, rather
than requiring us to store the port and prio into the sja1105_cbs_entry.

So, the problem is that the code programs the CBS shaper parameters at a
dynamic table index which is incorrect.

All that needs to be done for SJA1110 CBS shapers to work is to bypass
the logic which allocates shapers in a dense manner, as for SJA1105, and
use the fixed mapping instead.

Fixes: 3e77e59bf8cf ("net: dsa: sja1105: add support for the SJA1110 switch family")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The blamed commit left this delta behind:

  struct sja1105_cbs_entry {
 -	u64 port;
 -	u64 prio;
 +	u64 port; /* Not used for SJA1110 */
 +	u64 prio; /* Not used for SJA1110 */
  	u64 credit_hi;
  	u64 credit_lo;
  	u64 send_slope;
  	u64 idle_slope;
  };

but did not actually implement tc-cbs offload fully for the new switch.
The offload is accepted, but it doesn't work.

The difference compared to earlier switch generations is that now, the
table of CBS shapers is sparse, because there are many more shapers, so
the mapping between a {port, prio} and a table index is static, rather
than requiring us to store the port and prio into the sja1105_cbs_entry.

So, the problem is that the code programs the CBS shaper parameters at a
dynamic table index which is incorrect.

All that needs to be done for SJA1110 CBS shapers to work is to bypass
the logic which allocates shapers in a dense manner, as for SJA1105, and
use the fixed mapping instead.

Fixes: 3e77e59bf8cf ("net: dsa: sja1105: add support for the SJA1110 switch family")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: dsa: sja1105: fix -ENOSPC when replacing the same tc-cbs too many times</title>
<updated>2023-09-06T05:23:05+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2023-09-05T21:53:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=894cafc5c62ccced758077bd4e970dc714c42637'/>
<id>894cafc5c62ccced758077bd4e970dc714c42637</id>
<content type='text'>
After running command [2] too many times in a row:

[1] $ tc qdisc add dev sw2p0 root handle 1: mqprio num_tc 8 \
	map 0 1 2 3 4 5 6 7 queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 hw 0
[2] $ tc qdisc replace dev sw2p0 parent 1:1 cbs offload 1 \
	idleslope 120000 sendslope -880000 locredit -1320 hicredit 180

(aka more than priv-&gt;info-&gt;num_cbs_shapers times)

we start seeing the following error message:

Error: Specified device failed to setup cbs hardware offload.

This comes from the fact that ndo_setup_tc(TC_SETUP_QDISC_CBS) presents
the same API for the qdisc create and replace cases, and the sja1105
driver fails to distinguish between the 2. Thus, it always thinks that
it must allocate the same shaper for a {port, queue} pair, when it may
instead have to replace an existing one.

Fixes: 4d7525085a9b ("net: dsa: sja1105: offload the Credit-Based Shaper qdisc")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
After running command [2] too many times in a row:

[1] $ tc qdisc add dev sw2p0 root handle 1: mqprio num_tc 8 \
	map 0 1 2 3 4 5 6 7 queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 hw 0
[2] $ tc qdisc replace dev sw2p0 parent 1:1 cbs offload 1 \
	idleslope 120000 sendslope -880000 locredit -1320 hicredit 180

(aka more than priv-&gt;info-&gt;num_cbs_shapers times)

we start seeing the following error message:

Error: Specified device failed to setup cbs hardware offload.

This comes from the fact that ndo_setup_tc(TC_SETUP_QDISC_CBS) presents
the same API for the qdisc create and replace cases, and the sja1105
driver fails to distinguish between the 2. Thus, it always thinks that
it must allocate the same shaper for a {port, queue} pair, when it may
instead have to replace an existing one.

Fixes: 4d7525085a9b ("net: dsa: sja1105: offload the Credit-Based Shaper qdisc")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: dsa: sja1105: fix bandwidth discrepancy between tc-cbs software and offload</title>
<updated>2023-09-06T05:23:04+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2023-09-05T21:53:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=954ad9bf13c4f95a4958b5f8433301f2ab99e1f5'/>
<id>954ad9bf13c4f95a4958b5f8433301f2ab99e1f5</id>
<content type='text'>
More careful measurement of the tc-cbs bandwidth shows that the stream
bandwidth (effectively idleslope) increases, there is a larger and
larger discrepancy between the rate limit obtained by the software
Qdisc, and the rate limit obtained by its offloaded counterpart.

The discrepancy becomes so large, that e.g. at an idleslope of 40000
(40Mbps), the offloaded cbs does not actually rate limit anything, and
traffic will pass at line rate through a 100 Mbps port.

The reason for the discrepancy is that the hardware documentation I've
been following is incorrect. UM11040.pdf (for SJA1105P/Q/R/S) states
about IDLE_SLOPE that it is "the rate (in unit of bytes/sec) at which
the credit counter is increased".

Cross-checking with UM10944.pdf (for SJA1105E/T) and UM11107.pdf
(for SJA1110), the wording is different: "This field specifies the
value, in bytes per second times link speed, by which the credit counter
is increased".

So there's an extra scaling for link speed that the driver is currently
not accounting for, and apparently (empirically), that link speed is
expressed in Kbps.

I've pondered whether to pollute the sja1105_mac_link_up()
implementation with CBS shaper reprogramming, but I don't think it is
worth it. IMO, the UAPI exposed by tc-cbs requires user space to
recalculate the sendslope anyway, since the formula for that depends on
port_transmit_rate (see man tc-cbs), which is not an invariant from tc's
perspective.

So we use the offload-&gt;sendslope and offload-&gt;idleslope to deduce the
original port_transmit_rate from the CBS formula, and use that value to
scale the offload-&gt;sendslope and offload-&gt;idleslope to values that the
hardware understands.

Some numerical data points:

 40Mbps stream, max interfering frame size 1500, port speed 100M
 ---------------------------------------------------------------

 tc-cbs parameters:
 idleslope 40000 sendslope -60000 locredit -900 hicredit 600

 which result in hardware values:

 Before (doesn't work)           After (works)
 credit_hi    600                600
 credit_lo    900                900
 send_slope   7500000            75
 idle_slope   5000000            50

 40Mbps stream, max interfering frame size 1500, port speed 1G
 -------------------------------------------------------------

 tc-cbs parameters:
 idleslope 40000 sendslope -960000 locredit -1440 hicredit 60

 which result in hardware values:

 Before (doesn't work)           After (works)
 credit_hi    60                 60
 credit_lo    1440               1440
 send_slope   120000000          120
 idle_slope   5000000            5

 5.12Mbps stream, max interfering frame size 1522, port speed 100M
 -----------------------------------------------------------------

 tc-cbs parameters:
 idleslope 5120 sendslope -94880 locredit -1444 hicredit 77

 which result in hardware values:

 Before (doesn't work)           After (works)
 credit_hi    77                 77
 credit_lo    1444               1444
 send_slope   11860000           118
 idle_slope   640000             6

Tested on SJA1105T, SJA1105S and SJA1110A, at 1Gbps and 100Mbps.

Fixes: 4d7525085a9b ("net: dsa: sja1105: offload the Credit-Based Shaper qdisc")
Reported-by: Yanan Yang &lt;yanan.yang@nxp.com&gt;
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
More careful measurement of the tc-cbs bandwidth shows that the stream
bandwidth (effectively idleslope) increases, there is a larger and
larger discrepancy between the rate limit obtained by the software
Qdisc, and the rate limit obtained by its offloaded counterpart.

The discrepancy becomes so large, that e.g. at an idleslope of 40000
(40Mbps), the offloaded cbs does not actually rate limit anything, and
traffic will pass at line rate through a 100 Mbps port.

The reason for the discrepancy is that the hardware documentation I've
been following is incorrect. UM11040.pdf (for SJA1105P/Q/R/S) states
about IDLE_SLOPE that it is "the rate (in unit of bytes/sec) at which
the credit counter is increased".

Cross-checking with UM10944.pdf (for SJA1105E/T) and UM11107.pdf
(for SJA1110), the wording is different: "This field specifies the
value, in bytes per second times link speed, by which the credit counter
is increased".

So there's an extra scaling for link speed that the driver is currently
not accounting for, and apparently (empirically), that link speed is
expressed in Kbps.

I've pondered whether to pollute the sja1105_mac_link_up()
implementation with CBS shaper reprogramming, but I don't think it is
worth it. IMO, the UAPI exposed by tc-cbs requires user space to
recalculate the sendslope anyway, since the formula for that depends on
port_transmit_rate (see man tc-cbs), which is not an invariant from tc's
perspective.

So we use the offload-&gt;sendslope and offload-&gt;idleslope to deduce the
original port_transmit_rate from the CBS formula, and use that value to
scale the offload-&gt;sendslope and offload-&gt;idleslope to values that the
hardware understands.

Some numerical data points:

 40Mbps stream, max interfering frame size 1500, port speed 100M
 ---------------------------------------------------------------

 tc-cbs parameters:
 idleslope 40000 sendslope -60000 locredit -900 hicredit 600

 which result in hardware values:

 Before (doesn't work)           After (works)
 credit_hi    600                600
 credit_lo    900                900
 send_slope   7500000            75
 idle_slope   5000000            50

 40Mbps stream, max interfering frame size 1500, port speed 1G
 -------------------------------------------------------------

 tc-cbs parameters:
 idleslope 40000 sendslope -960000 locredit -1440 hicredit 60

 which result in hardware values:

 Before (doesn't work)           After (works)
 credit_hi    60                 60
 credit_lo    1440               1440
 send_slope   120000000          120
 idle_slope   5000000            5

 5.12Mbps stream, max interfering frame size 1522, port speed 100M
 -----------------------------------------------------------------

 tc-cbs parameters:
 idleslope 5120 sendslope -94880 locredit -1444 hicredit 77

 which result in hardware values:

 Before (doesn't work)           After (works)
 credit_hi    77                 77
 credit_lo    1444               1444
 send_slope   11860000           118
 idle_slope   640000             6

Tested on SJA1105T, SJA1105S and SJA1110A, at 1Gbps and 100Mbps.

Fixes: 4d7525085a9b ("net: dsa: sja1105: offload the Credit-Based Shaper qdisc")
Reported-by: Yanan Yang &lt;yanan.yang@nxp.com&gt;
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: dsa: use capital "OR" for multiple licenses in SPDX</title>
<updated>2023-08-24T19:02:53+00:00</updated>
<author>
<name>Krzysztof Kozlowski</name>
<email>krzysztof.kozlowski@linaro.org</email>
</author>
<published>2023-08-23T08:56:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=59da9885767a75df697c84c06aaf2296e10d85a4'/>
<id>59da9885767a75df697c84c06aaf2296e10d85a4</id>
<content type='text'>
Documentation/process/license-rules.rst and checkpatch expect the SPDX
identifier syntax for multiple licenses to use capital "OR".  Correct it
to keep consistent format and avoid copy-paste issues.

Signed-off-by: Krzysztof Kozlowski &lt;krzysztof.kozlowski@linaro.org&gt;
Reviewed-by: Kurt Kanzenbach &lt;kurt@linutronix.de&gt;
Reviewed-by: FLorian Fainelli &lt;florian.fainelli@broadcom.com&gt;
Link: https://lore.kernel.org/r/20230823085632.116725-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Documentation/process/license-rules.rst and checkpatch expect the SPDX
identifier syntax for multiple licenses to use capital "OR".  Correct it
to keep consistent format and avoid copy-paste issues.

Signed-off-by: Krzysztof Kozlowski &lt;krzysztof.kozlowski@linaro.org&gt;
Reviewed-by: Kurt Kanzenbach &lt;kurt@linutronix.de&gt;
Reviewed-by: FLorian Fainelli &lt;florian.fainelli@broadcom.com&gt;
Link: https://lore.kernel.org/r/20230823085632.116725-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
