Hi Scott, On Wed, 20 Mar 2013 14:36:05 -0500, Scott Wood <scottw...@freescale.com> wrote:
> On 03/20/2013 02:15:19 PM, Tom Rini wrote: > > On Wed, Mar 20, 2013 at 11:43:15AM -0500, Scott Wood wrote: > > > On 03/20/2013 09:58:36 AM, Wolfgang Denk wrote: > > > >Dear Albert, > > > > > > > >In message <20130320145927.2031b913@lilith> you wrote: > > > >> > > > >> I do understand what it does, but I still don't get why it > > should be > > > >> done, since precisely payload control transfer happens through > > > >bootm and > > > >> the like which already properly flush cache. > > > > > > It doesn't always happen through bootm. Standalone apps use the > > > "go" command. > > > > So, to try and be a bit more verbose about this, for U-Boot > > applications > > which use 'go', we still need to ensure cache coherence, which is why > > bootm does a cache flush, we need some way to flush in this case. > > It's also an issue with using the "cpu <n> release" command. > > > And in this case you aren't better served by say bootelf ? > > That wouldn't handle the "cpu release" case. In any case, "go" exists > and is currently the recommended way to launch a standalone application > in doc/README.standalone. > > > > It's a user command! How can it be dead code? I don't know of a > > > way to include a human user in a patchset... > > > > Can you hightlight what exactly causes the world today to go off and > > fail? Is the hello_world example app sufficient in this case or do we > > need something much larger? > > A user inside Freescale is running standalone performance test apps, > using both "go" and "cpu <n> release" (since the test needs to run on > all CPUs). They are seeing cache problems running on a T4240 if they > don't have this flush. This flush is architecturally required between > modifying/loading code and running it. Still, why make it a shell command? Since this user needs a flush with "go" and "cpu release", then we should add a programmatic global cache flush in the "go" and "cpu release" commands. > -Scott Amicalement, -- Albert. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
