From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kumar Gala Subject: Re: [RFC 0/7] Qualcomm SMEM, SMD, RPM and regulators Date: Tue, 30 Sep 2014 08:49:52 -0500 Message-ID: References: <1412037291-16880-1-git-send-email-bjorn.andersson@sonymobile.com> Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1412037291-16880-1-git-send-email-bjorn.andersson@sonymobile.com> Sender: linux-kernel-owner@vger.kernel.org To: Bjorn Andersson Cc: Andy Gross , Arnd Bergmann , Grant Likely , Ian Campbell , Lee Jones , Liam Girdwood , Mark Brown , Mark Rutland , Pawel Moll , Rob Herring , Samuel Ortiz , "open list:OPEN FIRMWARE AND..." , linux-arm-kernel@lists.infradead.org, linux-arm-msm , linux-kernel@vger.kernel.org, Jeffrey Hugo List-Id: devicetree@vger.kernel.org On Sep 29, 2014, at 7:34 PM, Bjorn Andersson wrote: > All Qualcomm platforms implements a shared heap among the processors = in the > SoC, used for sharing data with other parts of the system. >=20 > One consumer of items from this heap is the "Shared Memory Driver", a= ring > buffer based point-to-point communication mechanism used to send eith= er stream > or packet based data to remote processors. >=20 > Starting with 8x74 this system is used to talk to the Resource Power = Manager > (RPM), a power efficient "coprocessor" with responsibility of aggrega= te votes > from the various systems in the SoC related to regulators, clocks and= bus > frequencies. >=20 > The PMIC regulators and root clocks in these platforms are only acces= sible via > the RPM, so to get access to these we need the full chain of smem, sm= d, rpm and > a regulator driver implemented. And that is exactly what this series = provides. >=20 >=20 > A key outstanding question is where in the tree we should put the > implementation, for now I dropped them in drivers/soc/qcom but that's= only > because I don't know where to put it otherwise. I have not found any = equivalent > of the SMEM driver, SMD resembles mailbox and rpmsg - but comments in= that > patch on why it's neither. >=20 > RPM is a mfd and regulator is a regulator :) I still don=92t see why RPM support for either A-family or B-family sho= uld exist in MFD vis drivers/soc/qcom. What benefit is there in puttin= g this in MFD? I think both A and B-family support should be in drivers/soc/qcom for t= he current time being until we determine there is some framework that m= akes more sense in the future. I almost see RPM more like a bus contro= ller than anything else. Something like an I2C bus controller that tha= n has some set of devices off of that bus. - k --=20 Employee of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, host= ed by The Linux Foundation