[U-Boot] Rework the network stack
Hi all,
there is an issue with the current network stack using netconsole. It's impossible to use network commands as TFTP inside netconsole, because they try to run as atomic network commands.
The issue was already reported by Stefano Babic in 2010: [U-Boot] NetConsole and network API http://lists.denx.de/pipermail/u-boot/2010-August/075535.html
I run into the same problem: [U-Boot] netconsole: USB Ethernet connection dropping with ping or tftpboot http://lists.denx.de/pipermail/u-boot/2015-February/203838.html
I have looked at the current network stack. The stack is based on the concept of atomic network commands. The implementation for netconsole looks very confusing.
Sascha Hauer has reimplemented the network stack for Barebox: http://www.spinics.net/lists/u-boot-v2/msg00914.html
Looking at the current implementation of net.c looks very clean and well-designed.
What do you think about porting this to U-Boot?
Best regards Jörg Krause
Hi Jörg,
On Sat, Mar 21, 2015 at 3:33 AM, Jörg Krause joerg.krause@embedded.rocks wrote:
Hi all,
there is an issue with the current network stack using netconsole. It's impossible to use network commands as TFTP inside netconsole, because they try to run as atomic network commands.
The issue was already reported by Stefano Babic in 2010: [U-Boot] NetConsole and network API http://lists.denx.de/pipermail/u-boot/2010-August/075535.html
I worked around this problem here:
http://lists.denx.de/pipermail/u-boot/2012-August/129913.html
I run into the same problem: [U-Boot] netconsole: USB Ethernet connection dropping with ping or tftpboot http://lists.denx.de/pipermail/u-boot/2015-February/203838.html
I didn't understand what about your case was not able to work given the workaround I implemented previously. What was different about it?
I have looked at the current network stack. The stack is based on the concept of atomic network commands. The implementation for netconsole looks very confusing.
There is no doubt that netconsole is quite confusing as it exists today.
Sascha Hauer has reimplemented the network stack for Barebox: http://www.spinics.net/lists/u-boot-v2/msg00914.html
Looking at the current implementation of net.c looks very clean and well-designed.
Thanks for pointing this out. I hadn't gone to look at the network stack in barebox.
What do you think about porting this to U-Boot?
I can look into this. Naturally there are many other changes to u-boot network stack since the time barebox forked, so I expect such a port to be very intensive... most likely a near complete rewrite of Sascha's series, but I will investigate further.
Cheers, -Joe
Hi Joe,
On Sa, 2015-03-21 at 22:59 -0500, Joe Hershberger wrote:
Hi Jörg,
On Sat, Mar 21, 2015 at 3:33 AM, Jörg Krause joerg.krause@embedded.rocks wrote:
Hi all,
there is an issue with the current network stack using netconsole. It's impossible to use network commands as TFTP inside netconsole, because they try to run as atomic network commands.
The issue was already reported by Stefano Babic in 2010: [U-Boot] NetConsole and network API http://lists.denx.de/pipermail/u-boot/2010-August/075535.html
I worked around this problem here:
http://lists.denx.de/pipermail/u-boot/2012-August/129913.html
I know about this patch, and I understand the problem it tries to workaround. But it does not work for using netconsole with another protocol like ping. When for example ping enters the NetLoop() it will halt the network device.
The problem for this is here: if (eth_is_on_demand_init() || protocol != NETCONS) { eth_halt(); ... }
eth_is_on_demand_init() returns correctly with false, because PING != NETCONS. But the second expression results in true, because PING != NETCONS.
I run into the same problem: [U-Boot] netconsole: USB Ethernet connection dropping with ping or tftpboot http://lists.denx.de/pipermail/u-boot/2015-February/203838.html
I didn't understand what about your case was not able to work given the workaround I implemented previously. What was different about it?
I have looked at the current network stack. The stack is based on the concept of atomic network commands. The implementation for netconsole looks very confusing.
There is no doubt that netconsole is quite confusing as it exists today.
I tried to fix the issue, but it did not work properly.
Sascha Hauer has reimplemented the network stack for Barebox: http://www.spinics.net/lists/u-boot-v2/msg00914.html
Looking at the current implementation of net.c looks very clean and well-designed.
Thanks for pointing this out. I hadn't gone to look at the network stack in barebox.
What do you think about porting this to U-Boot?
I can look into this. Naturally there are many other changes to u-boot network stack since the time barebox forked, so I expect such a port to be very intensive... most likely a near complete rewrite of Sascha's series, but I will investigate further.
I had a look at the patches and the code base is not entirely the same. But maybe we should just stick to the crucial points of the new network stack:
1) A network device gets initialized when it becomes the current one and gets brought down when it's not used anymore or prior booting to Linux so the connection remains active all the time.
My thoughts about this one: Bringing the device down can be done in eth_unregister(). Initializing for the current device can be done in eth_current_changed(). What I like even better is to make eth_current_changed() the sole place for calling init() and halt(). It would have to be extend to take at least two parameters, eth_current and new_current. If eth_current is null just bring up the new device, if new_current is null just bring down the current device.
2) Replace the NetLoop by a connection list where each protocol uses a connection to send and receive packets.
This induce to port all protocols to use the new network, of cause.
In my opinion it would be also good to do some clean ups and restructuring of code. Put more functions into net-utils, is there a need for eth_init and so on.
Best regards Jörg Krause
Hi Jörg,
On 22 March 2015 at 14:37, Jörg Krause joerg.krause@embedded.rocks wrote:
Hi Joe,
On Sa, 2015-03-21 at 22:59 -0500, Joe Hershberger wrote:
Hi Jörg,
On Sat, Mar 21, 2015 at 3:33 AM, Jörg Krause joerg.krause@embedded.rocks wrote:
Hi all,
there is an issue with the current network stack using netconsole. It's impossible to use network commands as TFTP inside netconsole, because they try to run as atomic network commands.
The issue was already reported by Stefano Babic in 2010: [U-Boot] NetConsole and network API http://lists.denx.de/pipermail/u-boot/2010-August/075535.html
I worked around this problem here:
http://lists.denx.de/pipermail/u-boot/2012-August/129913.html
I know about this patch, and I understand the problem it tries to workaround. But it does not work for using netconsole with another protocol like ping. When for example ping enters the NetLoop() it will halt the network device.
The problem for this is here: if (eth_is_on_demand_init() || protocol != NETCONS) { eth_halt(); ... }
eth_is_on_demand_init() returns correctly with false, because PING != NETCONS. But the second expression results in true, because PING != NETCONS.
I run into the same problem: [U-Boot] netconsole: USB Ethernet connection dropping with ping or tftpboot http://lists.denx.de/pipermail/u-boot/2015-February/203838.html
I didn't understand what about your case was not able to work given the workaround I implemented previously. What was different about it?
I have looked at the current network stack. The stack is based on the concept of atomic network commands. The implementation for netconsole looks very confusing.
There is no doubt that netconsole is quite confusing as it exists today.
I tried to fix the issue, but it did not work properly.
Sascha Hauer has reimplemented the network stack for Barebox: http://www.spinics.net/lists/u-boot-v2/msg00914.html
Looking at the current implementation of net.c looks very clean and well-designed.
Thanks for pointing this out. I hadn't gone to look at the network stack in barebox.
What do you think about porting this to U-Boot?
I can look into this. Naturally there are many other changes to u-boot network stack since the time barebox forked, so I expect such a port to be very intensive... most likely a near complete rewrite of Sascha's series, but I will investigate further.
I had a look at the patches and the code base is not entirely the same. But maybe we should just stick to the crucial points of the new network stack:
- A network device gets initialized when it becomes the current one and
gets brought down when it's not used anymore or prior booting to Linux so the connection remains active all the time.
My thoughts about this one: Bringing the device down can be done in eth_unregister(). Initializing for the current device can be done in eth_current_changed(). What I like even better is to make eth_current_changed() the sole place for calling init() and halt(). It would have to be extend to take at least two parameters, eth_current and new_current. If eth_current is null just bring up the new device, if new_current is null just bring down the current device.
- Replace the NetLoop by a connection list where each protocol uses a
connection to send and receive packets.
This induce to port all protocols to use the new network, of cause.
In my opinion it would be also good to do some clean ups and restructuring of code. Put more functions into net-utils, is there a need for eth_init and so on.
Joe has done a lot of work to move U-Boot's network stack over to driver model. This is now at u-boot-dm/next waiting for the merge window to open.
The connection list idea does not sound like a hugely complex change. Are you thinking of trying it out?
Regards, Simon
Joe, Simon,
On Mo, 2015-03-23 at 10:46 -0600, Simon Glass wrote:
Hi Jörg,
On 22 March 2015 at 14:37, Jörg Krause joerg.krause@embedded.rocks wrote:
Hi Joe,
On Sa, 2015-03-21 at 22:59 -0500, Joe Hershberger wrote:
Hi Jörg,
On Sat, Mar 21, 2015 at 3:33 AM, Jörg Krause joerg.krause@embedded.rocks wrote:
Hi all,
there is an issue with the current network stack using netconsole. It's impossible to use network commands as TFTP inside netconsole, because they try to run as atomic network commands.
The issue was already reported by Stefano Babic in 2010: [U-Boot] NetConsole and network API http://lists.denx.de/pipermail/u-boot/2010-August/075535.html
I worked around this problem here:
http://lists.denx.de/pipermail/u-boot/2012-August/129913.html
I know about this patch, and I understand the problem it tries to workaround. But it does not work for using netconsole with another protocol like ping. When for example ping enters the NetLoop() it will halt the network device.
The problem for this is here: if (eth_is_on_demand_init() || protocol != NETCONS) { eth_halt(); ... }
eth_is_on_demand_init() returns correctly with false, because PING != NETCONS. But the second expression results in true, because PING != NETCONS.
I run into the same problem: [U-Boot] netconsole: USB Ethernet connection dropping with ping or tftpboot http://lists.denx.de/pipermail/u-boot/2015-February/203838.html
I didn't understand what about your case was not able to work given the workaround I implemented previously. What was different about it?
I have looked at the current network stack. The stack is based on the concept of atomic network commands. The implementation for netconsole looks very confusing.
There is no doubt that netconsole is quite confusing as it exists today.
I tried to fix the issue, but it did not work properly.
Sascha Hauer has reimplemented the network stack for Barebox: http://www.spinics.net/lists/u-boot-v2/msg00914.html
Looking at the current implementation of net.c looks very clean and well-designed.
Thanks for pointing this out. I hadn't gone to look at the network stack in barebox.
What do you think about porting this to U-Boot?
I can look into this. Naturally there are many other changes to u-boot network stack since the time barebox forked, so I expect such a port to be very intensive... most likely a near complete rewrite of Sascha's series, but I will investigate further.
I had a look at the patches and the code base is not entirely the same. But maybe we should just stick to the crucial points of the new network stack:
- A network device gets initialized when it becomes the current one and
gets brought down when it's not used anymore or prior booting to Linux so the connection remains active all the time.
My thoughts about this one: Bringing the device down can be done in eth_unregister(). Initializing for the current device can be done in eth_current_changed(). What I like even better is to make eth_current_changed() the sole place for calling init() and halt(). It would have to be extend to take at least two parameters, eth_current and new_current. If eth_current is null just bring up the new device, if new_current is null just bring down the current device.
- Replace the NetLoop by a connection list where each protocol uses a
connection to send and receive packets.
This induce to port all protocols to use the new network, of cause.
In my opinion it would be also good to do some clean ups and restructuring of code. Put more functions into net-utils, is there a need for eth_init and so on.
Joe has done a lot of work to move U-Boot's network stack over to driver model. This is now at u-boot-dm/next waiting for the merge window to open.
The connection list idea does not sound like a hugely complex change. Are you thinking of trying it out?
I have just noticed today the big series of u-boot-dm patches of Joe. I will try it out. But before I will start I want to discuss the concept. What do you think about my thoughts about bringing up and down a network device?
Best regards, Jörg
Hi,
On 23 March 2015 at 13:55, Jörg Krause joerg.krause@embedded.rocks wrote:
Joe, Simon,
On Mo, 2015-03-23 at 10:46 -0600, Simon Glass wrote:
Hi Jörg,
On 22 March 2015 at 14:37, Jörg Krause joerg.krause@embedded.rocks wrote:
Hi Joe,
On Sa, 2015-03-21 at 22:59 -0500, Joe Hershberger wrote:
Hi Jörg,
On Sat, Mar 21, 2015 at 3:33 AM, Jörg Krause joerg.krause@embedded.rocks wrote:
Hi all,
there is an issue with the current network stack using netconsole. It's impossible to use network commands as TFTP inside netconsole, because they try to run as atomic network commands.
The issue was already reported by Stefano Babic in 2010: [U-Boot] NetConsole and network API http://lists.denx.de/pipermail/u-boot/2010-August/075535.html
I worked around this problem here:
http://lists.denx.de/pipermail/u-boot/2012-August/129913.html
I know about this patch, and I understand the problem it tries to workaround. But it does not work for using netconsole with another protocol like ping. When for example ping enters the NetLoop() it will halt the network device.
The problem for this is here: if (eth_is_on_demand_init() || protocol != NETCONS) { eth_halt(); ... }
eth_is_on_demand_init() returns correctly with false, because PING != NETCONS. But the second expression results in true, because PING != NETCONS.
I run into the same problem: [U-Boot] netconsole: USB Ethernet connection dropping with ping or tftpboot http://lists.denx.de/pipermail/u-boot/2015-February/203838.html
I didn't understand what about your case was not able to work given the workaround I implemented previously. What was different about it?
I have looked at the current network stack. The stack is based on the concept of atomic network commands. The implementation for netconsole looks very confusing.
There is no doubt that netconsole is quite confusing as it exists today.
I tried to fix the issue, but it did not work properly.
Sascha Hauer has reimplemented the network stack for Barebox: http://www.spinics.net/lists/u-boot-v2/msg00914.html
Looking at the current implementation of net.c looks very clean and well-designed.
Thanks for pointing this out. I hadn't gone to look at the network stack in barebox.
What do you think about porting this to U-Boot?
I can look into this. Naturally there are many other changes to u-boot network stack since the time barebox forked, so I expect such a port to be very intensive... most likely a near complete rewrite of Sascha's series, but I will investigate further.
I had a look at the patches and the code base is not entirely the same. But maybe we should just stick to the crucial points of the new network stack:
- A network device gets initialized when it becomes the current one and
gets brought down when it's not used anymore or prior booting to Linux so the connection remains active all the time.
My thoughts about this one: Bringing the device down can be done in eth_unregister(). Initializing for the current device can be done in eth_current_changed(). What I like even better is to make eth_current_changed() the sole place for calling init() and halt(). It would have to be extend to take at least two parameters, eth_current and new_current. If eth_current is null just bring up the new device, if new_current is null just bring down the current device.
- Replace the NetLoop by a connection list where each protocol uses a
connection to send and receive packets.
This induce to port all protocols to use the new network, of cause.
In my opinion it would be also good to do some clean ups and restructuring of code. Put more functions into net-utils, is there a need for eth_init and so on.
Joe has done a lot of work to move U-Boot's network stack over to driver model. This is now at u-boot-dm/next waiting for the merge window to open.
The connection list idea does not sound like a hugely complex change. Are you thinking of trying it out?
I have just noticed today the big series of u-boot-dm patches of Joe. I will try it out. But before I will start I want to discuss the concept. What do you think about my thoughts about bringing up and down a network device?
Joe is the expert here.
With driver model the actual bring-up should be automatic (i.e. it is probed as soon as it is used).
Regards, Simon
On Mon, Mar 23, 2015 at 3:04 PM, Simon Glass sjg@chromium.org wrote:
Hi,
On 23 March 2015 at 13:55, Jörg Krause joerg.krause@embedded.rocks
wrote:
Joe, Simon,
On Mo, 2015-03-23 at 10:46 -0600, Simon Glass wrote:
Hi Jörg,
On 22 March 2015 at 14:37, Jörg Krause joerg.krause@embedded.rocks
wrote:
Hi Joe,
8<--snip
I had a look at the patches and the code base is not entirely the
same.
But maybe we should just stick to the crucial points of the new
network
stack:
- A network device gets initialized when it becomes the current
one and
gets brought down when it's not used anymore or prior booting to
Linux
so the connection remains active all the time.
I think that's a reasonable goal.
My thoughts about this one: Bringing the device down can be done in eth_unregister().
Initializing
for the current device can be done in eth_current_changed(). What I
like
even better is to make eth_current_changed() the sole place for
calling
init() and halt(). It would have to be extend to take at least two parameters, eth_current and new_current. If eth_current is null just bring up the new device, if new_current is null just bring down the current device.
This would fit into the driver model implementation differently. I'm not sure we care to change it in the old Ethernet support. All the more reason to upgrade to the DM implementation.
- Replace the NetLoop by a connection list where each protocol
uses a
connection to send and receive packets.
I wonder if that is more complex than needed. It is the case that the only concurrent operations we need is NetConsole and one other operation. ARP is already handled in sequence and should not need to be considered concurrent (even though it could be). Perhaps we can find a way to allow NetConsole to operate outside of the typical "packet handler'.
This induce to port all protocols to use the new network, of cause.
It would be nice to not need to change all protocols.
In my opinion it would be also good to do some clean ups and restructuring of code. Put more functions into net-utils, is there a need for eth_init and so on.
I certainly agree that there are more clean-ups to be done. I don't agree that they should be connected to this change. The more meaningless renames we have in the series the harder it is to see and grok the substantive changes. This is very apparent in Sascha's patch series. It would be much easier to read / port if not clouded by essentially unrelated refactoring.
Joe has done a lot of work to move U-Boot's network stack over to driver model. This is now at u-boot-dm/next waiting for the merge window to open.
The connection list idea does not sound like a hugely complex change. Are you thinking of trying it out?
Let's try to start simpler. We can refactor further if needed.
I have just noticed today the big series of u-boot-dm patches of Joe. I will try it out. But before I will start I want to discuss the concept. What do you think about my thoughts about bringing up and down a network device?
I think it can be done when probed. In fact I'm not sure there's a reason more than one cannot be started at a time. We can certainly have more than one probed at a time. We just need to remove them before booting to Linux. eth_pre_remove() already calls eth_get_ops(dev)->stop(dev).
Joe is the expert here.
With driver model the actual bring-up should be automatic (i.e. it is probed as soon as it is used).
As long as we move the call to eth_get_ops(current)->start(current); to the probe function, then this is true.
Regards, Simon
participants (3)
-
Joe Hershberger -
Jörg Krause -
Simon Glass