On Fri, Nov 27, 2009 at 8:58 AM, Nico Coesel <ncoe...@dealogic.nl> wrote: >> -----Original Message----- >> From: openocd-development-boun...@lists.berlios.de [mailto:openocd- >> development-boun...@lists.berlios.de] On Behalf Of Øyvind Harboe >> Sent: vrijdag 27 november 2009 7:59 >> To: openocd-development@lists.berlios.de >> Subject: [Openocd-development] Radically improving out of the boxperformance >> for armX >> >> How about enabling fast/DCC memory transfers by default? >> >> We could document a requirement that a correct target >> script would disable fast/DCC memory transfers if necessary. > > How would that affect users that a new to OpenOCD? If > there is a possibility that they run into trouble then it would > be better to leave it off and print a message instead OR > implement a fall-back scenario that tries to use DCC first > and then fall back to the standard transfer method. Otherwise > you'll see the same question repeated over and over on > the OpenOCD mailing list: 'why isn't it working?'.
Perhaps, but not necessarily. Note that memory transfers smaller than 128 bytes(?) are not done with DCC. This means that any reset init sequence that I've seen should be unaffected. It is before the CPU is running at full speed(during reset) that I see the biggest chance of DCC failing. Also DCC is only used when working memory is enabled. Presumably a new user would either take an existing script and tweak it(add working memory), here the it would fail after he tweaked it. I don't see a user starting *from scratch* and then not being able to disable parts until discovering that "working memory" makes it fail and then that working memory minus DCC does not make it fail. There was some talk about adding a simple checksum to the DCC algorithm that is read back and checked. It should be something *fast* though(a few instructions at most). Note that this may be superfluous as we detect an incorrect end address of a DCC transfer now, i.e. we catch the case where the open loop is too fast on the OpenOCD side. -- Øyvind Harboe US toll free 1-866-980-3434 / International +47 51 63 25 00 http://www.zylin.com/zy1000.html ARM7 ARM9 ARM11 XScale Cortex JTAG debugger and flash programmer _______________________________________________ Openocd-development mailing list Openocd-development@lists.berlios.de https://lists.berlios.de/mailman/listinfo/openocd-development
