From mboxrd@z Thu Jan 1 00:00:00 1970 From: Georgi Djakov Subject: Re: [PATCH] arm64: dts: msm8916: Move smem below hwlock Date: Wed, 24 Feb 2016 12:31:48 +0200 Message-ID: <56CD8694.1070009@linaro.org> References: <1456248071-30547-1-git-send-email-georgi.djakov@linaro.org> <56CC970B.4080602@linaro.org> <56CCA95C.9070207@linaro.org> <20160223190356.GA17346@hector.attlocal.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20160223190356.GA17346@hector.attlocal.net> Sender: linux-kernel-owner@vger.kernel.org To: Andy Gross Cc: Srinivas Kandagatla , devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org, linux-kernel@vger.kernel.org, mark.rutland@arm.com List-Id: devicetree@vger.kernel.org On 02/23/2016 09:03 PM, Andy Gross wrote: > On Tue, Feb 23, 2016 at 08:47:56PM +0200, Georgi Djakov wrote: >> On 23.02.16 =D0=B3. 19:29, Srinivas Kandagatla wrote: >>> >>> >>> On 23/02/16 17:21, Georgi Djakov wrote: >>>> When the SMEM is probed it defers as it depends on the hardware lo= ck, which >>>> is not available yet. But the SMD bus and RPM regulators and clock= s depend >>>> on SMEM and they defer too. The problem with this is that the orde= r of >>>> registering the devices is not optimal and also we may end with me= ssed >>>> up serial console as the RPM clocks are not registered yet.. >>> I noticed the same issue but was wondering why would we end up with= messed up serial console? >>> >>> Could you add more details on why serial console is messed up? >>> >>> I thought, serial driver has nothing to do with the rpm clocks dire= ctly! >>> >> >> If we don't have the rpm clocks registered, the uart clock is an orp= han >> and when clk_get_rate() is called on orphan clocks it returns 0 as r= ate. >> In our case the msm_serial driver calls clk_get_rate() and gets 0 ra= te >> as the parent rpm clock has not registered yet. The result is that t= he >> baudrate is set incorrectly. >=20 > This isn't a probe defer issue w/ the SMEM and hwspinlock. That work= s properly. Ok, agree. > This is an issue with the msm_serial either not probe deferring to wa= it for the > rpm clocks or not handling the case of the clk framework giving us a = 'bogus' > clock. Can we queue off the clk_get_rate being 0 to probe defer for = the rpm > clocks? (although that is hacky). The proper solution would be to handle this in the clock framework.