Yes, I have tried the first suggestion from Matthias Fuchs. But make it working with cache is very complex. So now I am trying the way that map one TLB entry to make USB hcca and data struct in uncached region. I think it's a easy way but not suitable for other platform.
Best Regards, Ryan Chen -----Original Message----- From: Markus Klotzbücher [mailto:[EMAIL PROTECTED] Sent: Saturday, May 17, 2008 12:25 AM To: Matthias Fuchs Cc: u-boot-users@lists.sourceforge.net; Ryan CHEN; [EMAIL PROTECTED]; [EMAIL PROTECTED]; Zhang Wei Subject: Re: [U-Boot-Users] U-Boot help request for OHCI driver with CPU cache on Hi Matthias, Matthias Fuchs <[EMAIL PROTECTED]> writes: > On Thursday 15 May 2008 10:37:04 Markus Klotzbücher wrote: >> > Could you suggest me how to solve the problem? >> > Is there any specific part of USB driver that requires cache handling? >> >> None that I'm aware of, but I could imagine that enabling caches >> might cause some kind of problems. > With U-Boot's current OHCI implementation you will run into trouble at > least with cache incoherent CPUs like the 4xx PowerPCs. The 4xx_enet > driver has been modified to deal with this stuff when data caches are enabled. > The USB OHCI driver will also need that kind of fixing (making the > code very ugly). An other approach would be to put the USB DMA > accessable memory into some non-cached memory. Perhaps this is much more > simple. Thanks for the explanation. Yes I agree that this is likely the problem. I'm wondering if the benefits of having the cache enabled is worth the pain of fixing (= making the code uglier) this at all. I somehow doubt it. Best regards Markus Klotzbuecher -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: [EMAIL PROTECTED] ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ U-Boot-Users mailing list U-Boot-Users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/u-boot-users
