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From: Stefan Roese <sr@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] ELF_RELOC causes strange I-cache issues
Date: Thu, 21 Oct 2010 13:03:16 +0200	[thread overview]
Message-ID: <201010211303.16760.sr@denx.de> (raw)
In-Reply-To: <4CC01719.30706@free.fr>

On Thursday 21 October 2010 12:34:01 Albert ARIBAUD wrote:
> > But with DCACHE ON, the USB Stick is not found - maybe a timing problem:
> > 
> > TOP9000>  dc off
> > Data (writethrough) Cache is OFF
> > TOP9000>  usb reset
> > (Re)start USB...
> > USB:   scanning bus for devices... 2 USB Device(s) found
> > 
> >         scanning bus for storage devices... 1 Storage Device(s) found
> > 
> > TOP9000>  dc on
> > Data (writethrough) Cache is ON
> > TOP9000>  usb reset
> > (Re)start USB...
> > USB:   scanning bus for devices... ERROR: CTL:TIMEOUT
> > 2 USB Device(s) found
> > 
> >         scanning bus for storage devices... 0 Storage Device(s) found
> > 
> > TOP9000>
> > 
> > 
> > Reinhard
> 
> If the USB controller uses DMA, then the DCache issue probably has to do
> with making sure to flush the (relevant lines of) cache before
> memory-to-device DMAs and to invalidate the (again, relevant lines of)
> cache after device-to-memory DMAs.

Correct. Note that the EHCI driver already supports such a mode with d-cache 
enabled. You need to set CONFIG_EHCI_DCACHE to enable these cache handling 
functions.
 
> And I suggest we move this dcache issue to its own discussion thread.

Yes. This should be analysed/handled independently.

Cheers,
Stefan

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DENX Software Engineering GmbH,      MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich,  Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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  parent reply	other threads:[~2010-10-21 11:03 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-20 18:49 [U-Boot] ELF_RELOC causes strange I-cache issues Wolfgang Denk
2010-10-20 20:12 ` Albert ARIBAUD
2010-10-20 20:54   ` Wolfgang Denk
2010-10-20 22:20     ` Joakim Tjernlund
2010-10-21  9:18     ` Albert Aribaud
2010-10-21  9:51       ` Heiko Schocher
2010-10-21 10:11         ` Reinhard Meyer
2010-10-21 10:34           ` Albert ARIBAUD
2010-10-21 10:49             ` Reinhard Meyer
2010-10-21 10:50             ` Heiko Schocher
2010-10-21 11:03             ` Stefan Roese [this message]
2010-10-21 10:54           ` Wolfgang Denk
2010-10-21 10:56         ` Albert ARIBAUD
2010-10-21 11:36           ` Wolfgang Denk
2010-10-21 11:45             ` Wolfgang Denk
2010-10-21 11:52               ` Stefano Babic
2010-10-21 11:53           ` Wolfgang Denk
2010-10-21 12:00           ` Wolfgang Denk
2010-10-21 12:53             ` Albert ARIBAUD
2010-10-21 11:28         ` Joakim Tjernlund
2010-10-21 10:05       ` Wolfgang Denk
2010-10-22 12:23 ` [U-Boot] [PATCH] ehci-hcd.c: fix hanging under higher load Wolfgang Denk
2010-10-22 19:51   ` Remy Bohmer
2010-10-22 12:26 ` [U-Boot] ELF_RELOC causes strange I-cache issues Wolfgang Denk
2010-10-22 13:19   ` Albert ARIBAUD
2010-10-22 13:28     ` Wolfgang Denk

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