From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [PATCH v17 3/4] soc: rockchip: power-domain: Add power domain driver Date: Wed, 02 Sep 2015 11:28:13 -0700 Message-ID: <7hbndkptfm.fsf@linaro.org> References: <1441184380-13827-1-git-send-email-wxt@rock-chips.com> <1441184380-13827-4-git-send-email-wxt@rock-chips.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <1441184380-13827-4-git-send-email-wxt@rock-chips.com> (Caesar Wang's message of "Wed, 2 Sep 2015 16:59:39 +0800") Sender: linux-kernel-owner@vger.kernel.org To: Caesar Wang Cc: heiko@sntech.de, ulf.hansson@linaro.org, devicetree@vger.kernel.org, linux@arm.linux.org.uk, arnd@arndb.de, ijc+devicetree@hellion.org.uk, linux-kernel@vger.kernel.org, linus.walleij@linaro.org, dmitry.torokhov@gmail.com, dianders@chromium.org, tomasz.figa@gmail.com, linux-rockchip@lists.infradead.org, robh+dt@kernel.org, galak@codeaurora.org, linux-arm-kernel@lists.infradead.org, mturquette@baylibre.com, "jinkun.hong" List-Id: devicetree@vger.kernel.org Caesar Wang writes: > This driver is found on RK3288 SoCs. > > In order to meet high performance and low power requirements, a power > management unit is designed or saving power when RK3288 in low power > mode. > The RK3288 PMU is dedicated for managing the power of the whole chip. > > PMU can work in the Low Power Mode by setting bit[0] of PMU_PWRMODE_CON > register. After setting the register, PMU would enter the Low Power mode. > In the low power mode, pmu will auto power on/off the specified power > domain, send idle req to specified power domain, shut down/up pll and > so on. All of above are configurable by setting corresponding registers. > > Signed-off-by: jinkun.hong > Signed-off-by: Caesar Wang [...] > +static void rockchip_pm_remove_one_domain(struct rockchip_pm_domain *pd) > +{ > + int i; > + > + for (i = 0; i < pd->num_clks; i++) { > + clk_unprepare(pd->clks[i]); > + clk_put(pd->clks[i]); > + } You don't set pd->num_clks = 0 here, which means other places that iterate over the clocks might race with this and try to use clocks that have been unprepared/put. This might be over-paranoid, but in particular, this could race with rockchip_pd_power(). Also not setting the pd->num_clks to zero would be a problem for a power-controller that is configured as a module which could be unloaded and reloaded (I know that doesn't really work now, but it will eventually, I hope.) Maybe use the mutex here? It should at least protect the zeroing of pm->num_clks. Kevin