From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755357Ab3HLBzH (ORCPT ); Sun, 11 Aug 2013 21:55:07 -0400 Received: from mailout4.samsung.com ([203.254.224.34]:27776 "EHLO mailout4.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755312Ab3HLBzE (ORCPT ); Sun, 11 Aug 2013 21:55:04 -0400 X-AuditID: cbfee691-b7fef6d000002d62-20-52084075e963 Date: Mon, 12 Aug 2013 10:55:01 +0900 From: Cho KyongHo To: Tomasz Figa Cc: "'Linux ARM Kernel'" , "'Linux IOMMU'" , "'Linux Kernel'" , "'Linux Samsung SOC'" , devicetree@vger.kernel.org, "'Joerg Roedel'" , "'Kukjin Kim'" , "'Prathyush'" , "'Rahul Sharma'" , "'Subash Patel'" , "'Grant Grundler'" , "'Antonios Motakis'" , kvmarm@lists.cs.columbia.edu, "'Sachin Kamat'" Subject: Re: [PATCH v9 14/16] iommu/exynos: add support for power management subsystems. Message-id: <20130812105501.d5c52155b378b5e2f4d4bb53@samsung.com> In-reply-to: <3833452.V3JQdooaWE@flatron> References: <003201ce941b$6e5a90e0$4b0fb2a0$@samsung.com> <1949492.N82v2nAcIY@flatron> <20130809164943.fe4b673e92b3f7680562f29b@samsung.com> <3833452.V3JQdooaWE@flatron> X-Mailer: Sylpheed 3.3.0 (GTK+ 2.10.14; i686-pc-mingw32) MIME-version: 1.0 Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrHIsWRmVeSWpSXmKPExsVy+t8zA91SB44ggx9nzCzu3D3HajH/CJB4 deQHk8WC/dYWnbM3sFv0LrjKZvHx1HF2i02Pr7FaXN41h81ixvl9TBYXVmxkt5iy6DCrxck/ vYwWLdd7mSxW7frD6MDv8eTgPCaP2Q0XWTx2zrrL7nHn2h42j/Ob1jB7bF5S7zH5xnJGj74t qxg9Pm+S87hy9AxTAFcUl01Kak5mWWqRvl0CV8bMqXuZClaKVPRt+c3awLiPv4uRk0NCwETi 9bsjjBC2mMSFe+vZuhi5OIQEljFKnD91mhmm6O7ny+wQiemMElP/XoOqmsQk8W5CD1MXIwcH i4CqxIKTCSANbAJaEqvnHgebKiKgLvFtSj87iM0s8INF4tM2PhBbWCBKYs/+mWA1vAKOEpdv PmQFsTkFNCVe7ZzBDDF/PaPExHvn2SCusJC40NTBDtEgKPFj8j0WiKFaEpu3NbFC2PISm9e8 BWuWEFjJIbH82wOwDSwCAhLfJh9iATlUQkBWYtMBqM8kJQ6uuMEygVFsFpKxs5CMnYVk7AJG 5lWMoqkFyQXFSelFpnrFibnFpXnpesn5uZsYIXE/cQfj/QPWhxiTgVZOZJYSTc4Hpo28knhD YzMjC1MTU2Mjc0sz0oSVxHnVW6wDhQTSE0tSs1NTC1KL4otKc1KLDzEycXBKNTCqVkXzWFWt c3kj4ftt9s21abtOrXm7c12/Sh3T3lCeNzUz31VPbJGKXN/PoSKhu8Yovb9p5+LnN1bqHl2c orxuYqbIVnX52wUHT++8fZBf1XmJQUbujHzGX59/nDzy9ajE9w1FXfwGm8Ouu8j+Y+C9t+GZ he3c/atuPqu62S7XwSMoOmmWyZ1/SizFGYmGWsxFxYkAss0fkBEDAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrNKsWRmVeSWpSXmKPExsVy+t9jQd1SB44gg9YjBhZ37p5jtZh/BEi8 OvKDyWLBfmuLztkb2C16F1xls/h46ji7xabH11gtLu+aw2Yx4/w+JosLKzayW0xZdJjV4uSf XkaLluu9TBardv1hdOD3eHJwHpPH7IaLLB47Z91l97hzbQ+bx/lNa5g9Ni+p95h8YzmjR9+W VYwenzfJeVw5eoYpgCuqgdEmIzUxJbVIITUvOT8lMy/dVsk7ON453tTMwFDX0NLCXEkhLzE3 1VbJxSdA1y0zB+gNJYWyxJxSoFBAYnGxkr4dpgmhIW66FjCNEbq+IUFwPUYGaCBhHWPGzKl7 mQpWilT0bfnN2sC4j7+LkZNDQsBE4u7ny+wQtpjEhXvr2boYuTiEBKYzSkz9ew3KmcQk8W5C D1MXIwcHi4CqxIKTCSANbAJaEqvnHmcEsUUE1CW+TekHG8Qs8INF4tM2PhBbWCBKYs/+mWA1 vAKOEpdvPmQFsTkFNCVe7ZzBDDF/PaPExHvn2SCusJC40NTBDtEgKPFj8j0WiKFaEpu3NbFC 2PISm9e8ZZ7AKDALSdksJGWzkJQtYGRexSiaWpBcUJyUnmukV5yYW1yal66XnJ+7iRGcVJ5J 72Bc1WBxiFGAg1GJh9fjC3uQEGtiWXFl7iFGCQ5mJRHeemOOICHelMTKqtSi/Pii0pzU4kOM ycDQmMgsJZqcD0x4eSXxhsYmZkaWRmYWRibm5qQJK4nzHmy1DhQSSE8sSc1OTS1ILYLZwsTB KdXAKPHs7sfrXC+9w2yLPl2weG77ccPbxVOyjTJP8X9c7LW/9rHutoktu/hLRWYHyUWl+Hec 6NFRsg7hTbk7b8eW5N8L1dZf/9ormTP9cpdbYmj1tzcOnSuvfvVbrDphcsDK6MoDd77MipGK exj8fH1wX+27J/bzd0dV+PWc2rZXQ9OcVfng7zmu+5RYijMSDbWYi4oTAQ+TVUVuAwAA DLP-Filter: Pass X-MTR: 20000000000000000@CPGS X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 09 Aug 2013 10:32:40 +0200, Tomasz Figa wrote: > On Friday 09 of August 2013 16:49:43 Cho KyongHo wrote: > > On Fri, 09 Aug 2013 01:03:05 +0200, Tomasz Figa wrote: > > > Hi KyongHo, > > > > > > nit: Please drop the trailing dot at the end of patch subject. > > > > Oh. I didn't catch that. > > Thank you. > > > > > On Thursday 08 of August 2013 18:41:17 Cho KyongHo wrote: > > > > This adds support for Advance Power Management and Runtime Power > > > > Management. > > > > > > This patch adds support for system-wide and runtime power management. > > > > Ok. > > > > > > Since System MMU is located in the same local power domain of its > > > > master H/W, System MMU must be initialized before it is working if > > > > its power domain was ever turned off. TLB invalidation according to > > > > unmapping on page tables must also be performed while power domain > > > > is > > > > turned on. > > > > > > > > This patch ensures that resume and runtime_resume(restore_state) > > > > functions in this driver is called before the calls to resume and > > > > runtime_resume callback functions in the drivers of master H/Ws. > > > > Likewise, suspend and runtime_suspend(save_state) functions in this > > > > driver is called after the calls to suspend and runtime_suspend in > > > > the > > > > drivers of master H/Ws. > > > > > > > > In order to get benefit of this support, the master H/W and its > > > > System > > > > MMU must resides in the same power domain in terms of Linux kernel. > > > > If > > > > a master H/W does not use generic I/O power domain, its driver must > > > > call iommu_attach_device() after its local power domain is turned > > > > on, > > > > iommu_detach_device before turned off. > > > > > > I don't get the point of this last paragraph. What a power domain can > > > be in other terms? Is there any other way to support power domains on > > > Exynos than generic power domains? > > > > I just addressed the case a device driver turns off local power of its > > device without the help of generic I/O powerdomain. > > Out of curiosity, do we have such cases for Exynos in mainline kernel? > IMHO this is what the generic PM core is for and drivers shouldn't care > about such low level PM details. I don't know if there is the case and I also agree with you. I hope that there is no case that I addressed. I just mentioned an exceptional case. The best way is that all device drivers of master H/W of System MMU register their defvice in a generic i/o powerdomain. Thank you. KyongHo.