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Re: [lwip-users] Connection freeze after 29200 Bytes


From: Norbert Kleber
Subject: Re: [lwip-users] Connection freeze after 29200 Bytes
Date: Sun, 7 Aug 2016 11:57:08 +0200
User-agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0

Hi Noam,


if the connection is dropped midway the controller will not leave the bootloader. The controller boards will be connected to a switch and if the firmware should be updated a laptop with a c++ program that manages the transmission of the image. The C++ program will warn the service technician about the failed update if it is not able to finish after a cetain number of tries. Therefore it shouldn't be possible to enter an uncomplete image. Each transmitted part will be checked after being burned into FLASH via an additional Checksum transmitted over controlconnection, that also applies for the whole file after completion. As soon as the controller had Flashed the last part and evaluated the checksum it sends a command on the controll connection to signal the completion of the process.

The 64k are not a necassity but were an idea as i said i missread the amount of RAM memory. I will reduce that amount.


sincerly,


Norbert



Am 07.08.2016 um 09:39 schrieb Noam Weissman:

Hi Norbert,

 

I am sorry but I did not understood that you are trying to burn the internal FLASH.

 

We normally use a small extern SPI FLASH so we first transfer the binary to the external

FLASH and only after we have the file and that it is OK (CRC OK) we delete the CPU application

area and burn the new FW.

 

What you are doing is dangerous. If for some reason connection dropped or the transferred file

Is corrupted you are left with a device that is not working.

 

You must think on a 100% safe way to upgrade your device.

 

Why do you need 64K for BL ?  our average serial BL is 16-20K … ST has an ETH BL example that is smallcheck it as well.

 

BR,

Noam.

 

 

From: lwip-users [mailto:address@hidden] On Behalf Of Norbert Kleber
Sent: Sunday, August 07, 2016 9:00 AM
To: address@hidden
Subject: Re: [lwip-users] Connection freeze after 29200 Bytes

 

Hi everyone,

 

first of all i'ld like to thank you for your fast responds.

@Noam:

I will try the suggested LwIP 1.41 on Monday.

The FLASH size is 1 MB and the sectors are 0-3 16kB, 4 64kB, 5-11 128kB.
Since my Bootloader application will occupy at least the sectors 0-3 I thought using 64kB.
The S-RAM are 192kB including the 64kB of the CCM.  Now that I think about it i was under the impression of having 512kB RAM guess i missread something. I will try reducing the chunks of data I send.

@Jan:

Might very well be. I took the freeing of the pbuf out of an example as well:
      u16_t plen;

      plen = ptr->len;
    
      /* continue with next pbuf in chain (if any) */
      p = ptr->next;
     
      if (p != NULL)
      {
        /* increment reference count for es->p */
        pbuf_ref(p);
      }
     
      /* free pbuf: will free pbufs up to es->p (because es->p has a reference count > 0) */
      pbuf_free(ptr);

sincerly,

Norbert

Am 06.08.2016 um 17:36 schrieb Noam Weissman:

Hi,

 

STM32F4 is a micro processor and not a processor with huge amount of RAM !

 

First of all I suggest using LwIP 1.41 and not the older 1.32 that has bugs.

 

Secondly do not use such large buffers there is no reasoning for that. Use the LwIP default

536 bytes or standard TCP size 1460 or similar.

 

If you define a large window that means you need to set a few buffer with that size and that's a big

issue. My default MSS size is 536 bytes and I have no problems sending or receiving large files 600-800K

 

The reason for using a small MSS size is that I also use a TCP server (telnet) like and I do not want

to use large buffers in order to send small chunks of data. This compromise is good for me.

 

Depending on the FLASH size you use. Normally FLASH uses a page size of 256 bytes and a sub sector

or sector that has 4K bytes. I do not see why you need to collect 64K bytes before you burn it to FLASH.

At maximum I think you need 4K, but again it depends on the FLASH itself.

 

If you can burn pages of 256 bytes what I will do is collect data into a 256 byte buffer and once I have

256 I will write that page. Take more data from the TCP packet and if it does not fill the 256 byte buffer

wait for the next TCP packet and add the fragmented data...

 

Once you get the last packet write what ever is left in the temporary buffer.

 

If you use a large FLASH (more then 2M byte) that need to erase a sub sector of 4K at most I would

define a 4K buffer and do the above.

 

BR,

Noam.

 

 


From: lwip-users <address@hidden> on behalf of Norbert Kleber <address@hidden>
Sent: Saturday, August 6, 2016 2:03 PM
To: address@hidden
Subject: [lwip-users] Connection freeze after 29200 Bytes

 

Hello everyone,

I ran into a problem while implementing the LwIP stack v1.3.2 onto the STM32F4 Evalboard.
My Intention is to build a bootloader application while using Raw API. I want to transmit the .bin file in Parts of 64kB (matching the CCM) to the microcontroller, put it into the CCM and after that is filled or all data is transmitted to write the data into the FLASH. As long the file to transfer is smaller than this magical 29200 Bytes every thing works fine, but if it exceeds that limit the TCP connection freezes after transmitting the 29200Bytes. Wireshark didn't see any messages following that freeze not even a keep alive message. If i stop my terminal program that is sending the data the frame for closing the connection is send and answered. To control the data transmission i have a second tcp connection to another port where i am sending control instructions like how many bytes to expect. The acknowledgements to these frames had somehow a decreasing window size.
That happens as follows:

  1. frame window is 2920
  2. receive frame length 13
  3. ack frame window 2907

 Is there a mistake in interfacing the lwIP stack? The windowsize update function is disabled.

I took the driver as well as the interface out of the ethernet example for STM32F4Evalboar + STM32F4DIS-BB from element 14.

i would be grateful for any hint.

sincerly,

Norbert




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