From mboxrd@z Thu Jan 1 00:00:00 1970 From: horms@verge.net.au (Simon Horman) Date: Thu, 13 Mar 2014 11:02:35 +0900 Subject: [PATCH] ARM: shmobile: Check r8a7791 MD21 at SMP boot In-Reply-To: References: <20140226095916.15676.99394.sendpatchset@w520> Message-ID: <20140313020231.GC16719@verge.net.au> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Feb 27, 2014 at 09:08:06AM +0100, Geert Uytterhoeven wrote: > Hi Magnus, > > On Thu, Feb 27, 2014 at 4:33 AM, Magnus Damm wrote: > >>> This is a reworked version of the APMU patch previously posted as > >>> [PATCH] ARM: shmobile: Check MD21 at SMP boot in case of APMU > >> > >> Your previous version also affected r8a7790/Lager. > >> Isn't this check no longer needed there? According to the Lager manual, > >> MD21 also enables hardware debug mode, and is also controlled by > >> SW8-4. Of course the CPU may behave differently, as the CPU cores > >> are different. > > > > Yes, you are correct that the previous version of the patch also > > affected Lager. And that both r8a7790 and r8a7791 mention the MD21 bit > > together with JTAG debugging. > > > > I recently used the patch on Lager and I discovered that I apparently > > had been running with MD21 on my Lager since forever, and surprisingly > > it worked regardless. Since there is no documentation on r8a7790 or > > r8a7791 I simply decided to handle them separately and only enable > > where it is needed. > > You could have been lucky? > > On Koelsch, I only had failures after Real Cold Boot, i.e. on boot up in the > morning. And not always, so there could be a timing issue involved. > > > I've also been told that it is possible to allow SMP operation > > together with JTAG, apparently some magic with RST is needed. It seems > > that the power domains are treated differently depending on the MD21 > > setting. Not sure if this applies to both r8a7790 and r8a7791, but if > > we end up with similar fixes we can consolidate. Until then I think > > dealing with them one by one makes sense. > > Furthermore, I haven't seen any SPI timeouts after I disabled MD21 (holding > wood, and rabbit legs ;-). So the SMP memory (in)coherency I saw there > could have been caused by a wobbly SMP setup. Hi Magnus, I am a little confused about the status of this patch? Would you like me to queue it up?