From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756220AbcHCF7E (ORCPT ); Wed, 3 Aug 2016 01:59:04 -0400 Received: from mailgw01.mediatek.com ([210.61.82.183]:11265 "EHLO mailgw01.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753679AbcHCF66 (ORCPT ); Wed, 3 Aug 2016 01:58:58 -0400 Message-ID: <1470203182.17063.3.camel@mtksdaap41> Subject: Re: [PATCH v9 01/10] clk: fix initial state of critical clock's parents From: James Liao To: Michael Turquette CC: Stephen Boyd , Erin Lo , Matthias Brugger , Rob Herring , John Crispin , Arnd Bergmann , "Sascha Hauer" , Daniel Kurtz , Philipp Zabel , , , , , , Date: Wed, 3 Aug 2016 13:46:22 +0800 In-Reply-To: <1468225452.31247.7.camel@mtksdaap41> References: <1466581229-2342-1-git-send-email-erin.lo@mediatek.com> <1466581229-2342-2-git-send-email-erin.lo@mediatek.com> <20160702012140.GB17071@codeaurora.org> <1467604308.26485.4.camel@mtksdaap41> <146802073038.73491.6675612765998057903@resonance> <1468225452.31247.7.camel@mtksdaap41> Content-Type: text/plain; charset="us-ascii" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit MIME-Version: 1.0 X-MTK: N Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2016-07-11 at 16:24 +0800, James Liao wrote: > Hi Mike, > > On Fri, 2016-07-08 at 16:32 -0700, Michael Turquette wrote: > > Hi James, > > > > Quoting James Liao (2016-07-03 20:51:48) > > > On Fri, 2016-07-01 at 18:21 -0700, Stephen Boyd wrote: > > > > (Resending to everyone) > > > > > > > > On 06/22, Erin Lo wrote: > > > > > From: James Liao > > > > > > > > > > This patch fixed wrong state of parent clocks if they are registered > > > > > after critical clocks. > > > > > > > > > > Signed-off-by: James Liao > > > > > Signed-off-by: Erin Lo > > > > > > > > It would be nice if you included the information about the > > > > problem from James' previous mail. This says what it does, but > > > > doesn't explain what the problem is and how it is fixing it. > > > > > > > > > --- > > > > > drivers/clk/clk.c | 9 ++++++++- > > > > > 1 file changed, 8 insertions(+), 1 deletion(-) > > > > > > > > > > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c > > > > > index d584004..e9f5f89 100644 > > > > > --- a/drivers/clk/clk.c > > > > > +++ b/drivers/clk/clk.c > > > > > @@ -2388,8 +2388,15 @@ static int __clk_core_init(struct clk_core *core) > > > > > hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) { > > > > > struct clk_core *parent = __clk_init_parent(orphan); > > > > > > > > > > - if (parent) > > > > > + if (parent) { > > > > > clk_core_reparent(orphan, parent); > > > > > + > > > > > + if (orphan->prepare_count) > > > > > + clk_core_prepare(parent); > > > > > + > > > > > + if (orphan->enable_count) > > > > > + clk_core_enable(parent); > > > > > + } > > > > > } > > > > > > > > I'm pretty sure I pointed this problem out to Mike when the > > > > critical clk patches were being pushed. I can't recall what the > > > > plan was though to fix the problem. I'm pretty sure he said that > > > > clk_core_reparent() would take care of it, but obviously it is > > > > not doing that. Or perhaps it was that clk handoff should figure > > > > out that the parents of a critical clk are also on and thus keep > > > > them on. > > > > > > Hi Mike > > > > > > Is there any other patch to fix this issue? Or did I misuse critical > > > clock flag? > > > > There is no fix yes. Your fix is basically correct. I was mistaken back > > when I told you and Stephen that the framework already took care of > > this. > > > > However, instead of "open coding" this solution, I would rather re-use > > the __clk_set_parent_{before,after} helpers instead. Can you review/test > > the following patch and let me know what you think? > > > > Thanks, > > Mike > > > > > > > > From c0163b3f719b1e219b28ad425f94f9ef54a25a8f Mon Sep 17 00:00:00 2001 > > From: Michael Turquette > > Date: Fri, 8 Jul 2016 16:05:22 -0700 > > Subject: [PATCH] clk: migrate ref counts when orphans are reunited > > > > It's always nice to see families reunited, and this is equally true when > > talking about parent clocks and their children. However, if the orphan > > clk had a positive prepare_count or enable_count, then we would not > > migrate those counts up the parent chain correctly. > > > > This has manifested with the recent critical clocks feature, which often > > enables clocks very early, before their parents have been registered. > > > > Fixed by replacing the call to clk_core_reparent with calls to > > __clk_set_parent_{before,after}. > > > > Cc: James Liao > > Cc: Erin Lo > > Signed-off-by: Michael Turquette > > --- > > drivers/clk/clk.c | 10 ++++++++-- > > 1 file changed, 8 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c > > index 820a939fb6bb..70efe4c4e0cc 100644 > > --- a/drivers/clk/clk.c > > +++ b/drivers/clk/clk.c > > @@ -2449,8 +2449,14 @@ static int __clk_core_init(struct clk_core *core) > > hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) { > > struct clk_core *parent = __clk_init_parent(orphan); > > > > - if (parent) > > - clk_core_reparent(orphan, parent); > > Is it correct to remove clk_core_reparent()? It lacks > __clk_recalc_accuracies() and __clk_recalc_rates(), so the new parent's > rate will not propagate correctly. > > For example, I set vdec_sel as a critical clock. Without your patch, the > result was: > > vdecpll 0 0 338000000 > vdecpll_ck 1 1 338000000 > vdec_sel 1 1 338000000 > > With your patch, it became: > > vdecpll 1 1 338000000 > vdecpll_ck 1 1 0 > vdec_sel 1 1 0 > > The prepare_count and enable_count are correct with your patch, but the > rates of vdecpll_ck and vdec_sel become incorrect. > > > Best regards, > > James > > > + /* > > + * we could call __clk_set_parent, but that would result in a > > + * reducant call to the .set_rate op, if it exists > > + */ > > + if (parent) { > > + __clk_set_parent_before(orphan, parent); > > + __clk_set_parent_after(orphan, parent, NULL); > > + } > > } > > > > /* > Hi Mike, Do you have new patches to fix new clock parents? If not, I think we can use my patch first. Is it okay? Best regards, James