[U-Boot-Users] Re : MV64460 Burst reads from BootCS

Hi, Marvell MV64460 only supports burst reads/writes on 32bits width peripherals ;-( I have the same issue with a Lauterbach probe. You must deny burst on BootCS if this peripheral is not 32bits width ! This restriction also penalize boot process ! If your boot flash is 16 or 8 bits witdh, you can't directly execute instructions in flash. Because CPU like MPC74xx always load instructions with burst reads.
Regards. Sebastien.
Message: 5 Date: Sun, 1 Oct 2006 20:19:12 +0200 From: "Roel Loeffen" roel.loeffen@prodrive.nl Subject: [U-Boot-Users] MV64460 Burst reads from BootCS To: u-boot-users@lists.sourceforge.net Message-ID:
7826EB01AD927140A1DCF898FE63325D0D91B1@ExchangeSrv.Prodrive.nl
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Hi all,
We discover some serious problems accessing flash at BootCS of the Marvell MV64460. It looks like burst reads make the whole bridge hang. >From inside U-Boot as well as using only the BDI2000 debugger.
Reading the flash with bursts enabled (which is default), makes it sometimes impossible to access any registers/dram/devices anymore, only zeros can be read.
It also freezes the CPU somehow the debugger cannot halt it anymore with a normal halt (COP halt), it has to use COP freeze to take over control again.
I cannot say this problem does not occur accessing other spaces, so it can also be a problem at the PPC60x bus.
Has anyone over excpirianced this before?
Thanks in advance!
Roel
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sebastien.douheret wrote:
Hi, Marvell MV64460 only supports burst reads/writes on 32bits width peripherals ;-( I have the same issue with a Lauterbach probe. You must deny burst on BootCS if this peripheral is not 32bits width ! This restriction also penalize boot process ! If your boot flash is 16 or 8 bits witdh, you can't directly execute instructions in flash. Because CPU like MPC74xx always load instructions with burst reads.
Regards. Sebastien.
I don't believe the above is strictly correct. The 74xx does burst reads only if the cache is enabled for that memory area, so you should be able to execute out of flash but would be unable to enable caching on the boot memory area. After all, I presume the board boots out of flash.
gvb
participants (2)
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Jerry Van Baren
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sebastien.douheret