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Ethernet Stack restart

Posted by shaanktn on May 4, 2017

Hi all, I am in a scenario where I need to restart/reinit the Ethernet stack. I have STM32Fxx driver and code, Is there any built-in function to do the same ? I will be setting the new IP and related params before this reset. MAC ID will be same, so I believe I don't have to recreate the IP task. HALETHStart/Stop is not helping much there. I am able to get my required functionality done with just FreeRTOSSetIPAddress() and others params, but not reliable, few times I get issue(for which I am thinking of reset now) as I have multiple tasks and control is sliced to other tasks also. The issue is after I try to set new IP, I see the timeout for ping requests(nothing from stack will be responsive), I don't see any assert/hang. Is there any other way to read the device IP other than FreeRTOSGetIPAddress()?. Any input on phy/stack reset related will be helpful.

Thanks, Shaank


Ethernet Stack restart

Posted by shaanktn on May 8, 2017

I am receiving the "ETHDMAIT_RO" status in IRQ handler, even if I reset it, not helping. It toggles back to same. What are the possibilities for this and how can I resolve this ?


Ethernet Stack restart

Posted by heinbali01 on May 8, 2017

Hi Shaank, The latest version of the STM32F4 driver is not on /Labs yet, but you can download it here

I am receiving the "ETHDMAIT_RO" status in IRQ handler, even if I reset it, not helping. It toggles back to same. What are the possibilities for this and how can I resolve this ?

You're getting this error:

~~~ /* * Bit 4 ROS: Receive overflow status * This bit indicates that the receive buffer had an * overflow during frame reception. If the partial * frame is transferred to the application, the * overflow status is set in RDES0[11]. / #define ETHDMAITRO ((uint32t)0x00000010) /!< Overflow interrupt */ ~~~

My feeling says: that should never occur! Are you supplying internal SRAM to the DMA, both for the descriptors as well as for the network buffers? Do you give proper memory, or have the descriptors been corrupted? Are you using any external (S)DRAM at all? Ethernet is fast, the DMA must transport data at 10 MByte per second. Do you have concurrent DMA transports? Can you play with their priorities? I will answer your earlier question later on. Hein


Ethernet Stack restart

Posted by shaanktn on May 8, 2017

Hey Hein, I use external SDRAM for my firmware. Anyways its not the throughput/performance issue is problem for me it looks like, I have multiple threads being sliced(2ms) in my platform, doing different activities like write to flash/read/display/ etc. So when new config is being downloaded, I feel it takes the ticks away from emac task for a while. I have reduced the emac task priority and its been sliced by my task scheduler. Will that cause the problem for stack? Bwn, first qn is more of front end observation, we can ignore now ! Thanks,


Ethernet Stack restart

Posted by heinbali01 on May 9, 2017

I am in a scenario where I need to restart/reinit the Ethernet stack. I have STM32Fxx driver and code, Is there any built-in function to do the same ? I will be setting the new IP and related params before this reset. MAC ID will be same, so I believe I don't have to recreate the IP task.

That is right, both the IP-task as well as the EMAC task ( prvEMACHandlerTask ) will keep on running. The EMAC does not need a reset. If you want to change the MAC-address ( which you do not want to ), you can write the new MAC address into some registers. You could do that every time when xNetworkInterfaceInitialise() is called by calling prvMACAddressConfig().

HALETHStart/Stop is not helping much there.

Right, the EMAC settings haven't change so the EMAC is not the problem.

I am able to get my required functionality done with just FreeRTOSSetIPAddress() and others params, but not reliable, few times I get issue (for which I am thinking of reset now) as I have multiple tasks and control is sliced to other tasks also. The issue is after I try to set new IP, I see the timeout for ping requests (nothing from stack will be responsive), I don't see any assert/hang. Is there any other way to read the device IP other than FreeRTOSGetIPAddress()?. Any input on phy/stack reset related will be helpful.

I think that you won't be able to solve that problem on the embedded side. The problem is that you change a binding of a MAC-address with an IP-address. The host that you are working on is still using the old binding. If my reasoning is true, the following should help within Windows: start a command prompt as an administrator. Enter the command arp /d * to clean the local ARP tables. For Linux: sudo ip -s -s neigh flush all.

Beside that, you might see some time-outs, things might not work immediately.

Another issue that may occur is that the device does not connect through TCP after rebooting. That may be caused by the fact that your ipconfigRAND32() function does not get a unique seed after booting. When a TCP socket is bound to port 0, a random port number will be assigned. After a reboot, these port numbers should start at a different number. Another thing that should be random is the Initial Sequence Number in a TCP connection. When the device uses the same port and the same initial sequence number, the connection is bound to fail. Hein


Ethernet Stack restart

Posted by heinbali01 on May 9, 2017

Hi Shaank,

I use external SDRAM for my firmware.

Are you providing SDRAM memory to DMA? Either as data buffer or as DMA descriptors?

If so, I would try to use internal SRAM for that purpose, and the DMA error ETH_DMA_IT_RO will disappear.

Anyway, its not the throughput/performance issue is problem for me it looks like, I have multiple threads being sliced(2ms) in my platform, doing different activities like write to flash/read/display/ etc. So when new config is being downloaded, I feel it takes the ticks away from emac task for a while. I have reduced the emac task priority and its been sliced by my task scheduler. Will that cause the problem for stack?

The ETH_DMA_IT_RO error is not caused by tasks that are too late or too slow.

We advice the following scheme for priorities when using FreeRTOS+TCP:

Prio-4 High-priority tasks that do not use +TCP Prio-3 prvEMACHandlerTask, deferred EMAC interrupt handler Prio-2 IP-task ( ipconfigIPTASKPRIORITY ) Prio-1 Application tasks that do use +TCP

Regards.


Ethernet Stack restart

Posted by shaanktn on May 12, 2017

Hi Hein, Thanks for the inputs, also for thread priority scheme. Ideally its not setting IP or those API's causing it(which I thought its that time causing the issue), inbetween if I take some time away from enet thread at some particular instance, faced the issue. Are you providing SDRAM memory to DMA? Either as data buffer or as DMA descriptors? Yes, I provide SDRAM to DMA and using it as DMA descriptors. And the board starts working back after the restart. Now I increased the ETH_RXBUFNB to 16 from 4, it works better than before. Internal SRAM is rused by for bootloader and did not try moving DMA there yet.


Ethernet Stack restart

Posted by heinbali01 on May 12, 2017

Are you providing SDRAM memory to DMA? Either as data buffer or as DMA descriptors?

Yes, I provide SDRAM to DMA and using it as DMA descriptors.

Well, it doesn't matter unless you see DMA overflow (ETH_DMA_IT_RO) of underflow (ETH_DMA_IT_TU) errors.


Ethernet Stack restart

Posted by shaanktn on May 12, 2017

Hi Hein, So you suggest moving it to internal SRAM will be the best approach ? Increasing the buffer also expected to give issues at point of time ?


Ethernet Stack restart

Posted by heinbali01 on May 12, 2017

Only in case you still see one of these errors: ETH_DMA_IT_RO or ETH_DMA_IT_TU. What happens if you define ETH_RXBUFNB as 2 ? Will you see under- or overflow errors?


Ethernet Stack restart

Posted by shaanktn on May 12, 2017

When I increase it to 16 I see the ETHDMAITRO very rare. If I decrease it to 2, I see it very much easily! Between I never got ETHDMAITTU. I see it as 0x8010 (heth->Instance->DMASR in HALETHIRQHandler).


Ethernet Stack restart

Posted by heinbali01 on May 12, 2017

Thanks for trying, now I'm convinced that the overflow error only means that there are not enough buffers. And it has nothing to do with the speed of the memory itself. Regards.


Ethernet Stack restart

Posted by shaanktn on May 17, 2017

Hi, any info regarding ETHDMAIT_RBU bit being set ? This should be cleared in IRQ handler ? Or I will have to check on buffers itself ?


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