From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4E26AFF4.9000208@freescale.com> From: Huang Shijie MIME-Version: 1.0 To: Wolfram Sang Subject: Re: [i.MX28 GPMI] problem overwriting all-0xff data in NAND References: <20004.12663.29494.339601@ipc1.ka-ro> <20110718164354.GA3328@S2100-06.ap.freescale.net> <4E24E804.10002@freescale.com> <20005.7677.145955.789329@ipc1.ka-ro> <4E252C51.8070900@freescale.com> <20005.21635.427202.49313@ipc1.ka-ro> <4E263AF2.60103@freescale.com> <20110720085142.GA2377@pengutronix.de> In-Reply-To: <20110720085142.GA2377@pengutronix.de> Content-Type: multipart/alternative; boundary="------------010006070700050406010800" Cc: linux-mtd@lists.infradead.org, linux-arm-kernel@lists.infradead.org, Shawn Guo , =?UTF-8?B?TG90aGFyIFdhw59tYW5u?= List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Date: Wed, 20 Jul 2011 10:34:26 -0000 --------------010006070700050406010800 Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit Hi, >>>>>>> I am debugging the DMA bug now. and I will send it out when i fix it. >>>>>>> >>>>>> What sort of DMA bug? >>>>>> >>>>> The DMA may time-out. :( >>>>> >>>>> The DMA time-out may occur in two situations: >>>>> [1] send a command DMA descriptor, see the nfc->send_command() function. >>>>> [2] read the non-ecc data from nand, see the nfc->read_data() function. >>>>> >>>>> I don't know why. Maybe caused by the timing, or something else. >>> I am confused. The send-command DMA timeout prevents any write for me. >>> You guys surely would have noticed if you have been bitten as well. Does >>> it depend on the NAND chip? >> I think It does not depend on the NAND chip. >> My test chip is Samsung K9G8G08U0M. >> Sometimes, I can run a long time while there is no DMA timeout occurring; >> Sometimes, the bug appears right away. > For me, the bug always happens right away. So, if you need logs or debug > output or can give me a pointer into some direction, I am glad to > assist. > Thanks a lot. :) I am trying to merge the two DMA descriptors into one in the send_command(). The original bsp code used only one DMA descriptor. Huang Shijie > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel --------------010006070700050406010800 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: 7bit Hi,

      

        

          

            

              

                

                  
I am debugging the DMA bug now. and I will send it out when i fix it.



                

                
What sort of DMA bug?



              

              
The DMA may time-out. :(

The DMA time-out may occur in two situations:
[1] send a command DMA descriptor, see the nfc->send_command() function.
[2] read the non-ecc data from nand, see the nfc->read_data() function.

I don't know why. Maybe caused by the timing, or something else.


            

          

          
I am confused. The send-command DMA timeout prevents any write for me.
You guys surely would have noticed if you have been bitten as well. Does
it depend on the NAND chip?


        

        
I think It does not depend on the NAND chip.
My test chip is Samsung K9G8G08U0M.
Sometimes, I can run a long time while there is no DMA timeout occurring;
Sometimes, the bug appears right away.


      

      
For me, the bug always happens right away. So, if you need logs or debug
output or can give me a pointer into some direction, I am glad to
assist.



    

    Thanks a lot. :)

    

    I am trying to merge the two DMA descriptors into one in the
    send_command().

    The original bsp code used only one DMA descriptor.

    

    

    

    Huang Shijie

    

      

      

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