From mboxrd@z Thu Jan 1 00:00:00 1970 From: Evan Green Subject: Re: [PATCH v5 12/20] memory: mtk-smi: Add gals support Date: Wed, 30 Jan 2019 10:30:55 -0800 Message-ID: References: <1546314952-15990-1-git-send-email-yong.wu@mediatek.com> <1546314952-15990-13-git-send-email-yong.wu@mediatek.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1546314952-15990-13-git-send-email-yong.wu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+glpam-linux-mediatek=m.gmane.org-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org To: Yong Wu Cc: youlin.pei-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Nicolas Boichat , Arnd Bergmann , srv_heupstream-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, Joerg Roedel , Will Deacon , LKML , Tomasz Figa , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Rob Herring , linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Matthias Brugger , yingjoe.chen-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, Robin Murphy , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: iommu@lists.linux-foundation.org On Mon, Dec 31, 2018 at 7:58 PM Yong Wu wrote: > > In some SoCs like mt8183, SMI add GALS(Global Async Local Sync) module > which can help synchronize for the modules in different clock frequency. > It can be seen as a "asynchronous fifo". This is a example diagram: > > M4U > | > ---------- > | | > gals0-rx gals1-rx > | | > | | > gals0-tx gals1-tx > | | > ------------ > SMI Common > ------------ > | > +-----+--------+-----+- ... > | | | | > | gals-rx gals-rx | > | | | | > | | | | > | gals-tx gals-tx | > | | | | > larb1 larb2 larb3 larb4 > > GALS only help transfer the command/data while it doesn't have the > configuring register, thus it has the special "smi" clock and doesn't > have the "apb" clock. From the diagram above, we add "gals0" and > "gals1" clocks for smi-common and add a "gals" clock for smi-larb. > > This patch adds gals clock supporting in the SMI. Note that some larbs > may still don't have the "gals" clock like larb1 and larb4 above. > > This is also a preparing patch for mt8183 which has GALS. > > Signed-off-by: Yong Wu So really from a software perspective the gals are just a couple of extra clocks that need to be turned on for certain larbs. Seems fine to me. Reviewed-by: Evan Green