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[104.188.17.28]) by smtp.gmail.com with ESMTPSA id t16sm9912477pgo.80.2020.02.14.23.33.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Feb 2020 23:33:24 -0800 (PST) Date: Fri, 14 Feb 2020 23:32:33 -0800 From: Bjorn Andersson To: Mike Tipton Cc: sboyd@kernel.org, tdas@codeaurora.org, mturquette@baylibre.com, agross@kernel.org, linux-arm-msm@vger.kernel.org, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] clk: qcom: clk-rpmh: Wait for completion when enabling clocks Message-ID: <20200215073233.GR955802@ripper> References: <20200215021232.1149-1-mdtipton@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200215021232.1149-1-mdtipton@codeaurora.org> Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Fri 14 Feb 18:12 PST 2020, Mike Tipton wrote: > The current implementation always uses rpmh_write_async, which doesn't > wait for completion. That's fine for disable requests since there's no > immediate need for the clocks and they can be disabled in the > background. However, for enable requests we need to ensure the clocks > are actually enabled before returning to the client. Otherwise, clients > can end up accessing their HW before the necessary clocks are enabled, > which can lead to bus errors. > > Use the synchronous version of this API (rpmh_write) for enable requests > in the active set to ensure completion. > > Completion isn't required for sleep/wake sets, since they don't take > effect until after we enter sleep. All rpmh requests are automatically > flushed prior to entering sleep. > > Fixes: 9c7e47025a6b ("clk: qcom: clk-rpmh: Add QCOM RPMh clock driver") > Signed-off-by: Mike Tipton Reviewed-by: Bjorn Andersson Regards, Bjorn > --- > drivers/clk/qcom/clk-rpmh.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > diff --git a/drivers/clk/qcom/clk-rpmh.c b/drivers/clk/qcom/clk-rpmh.c > index 12bd8715dece..3137595a736b 100644 > --- a/drivers/clk/qcom/clk-rpmh.c > +++ b/drivers/clk/qcom/clk-rpmh.c > @@ -143,6 +143,19 @@ static inline bool has_state_changed(struct clk_rpmh *c, u32 state) > != (c->aggr_state & BIT(state)); > } > > +static int clk_rpmh_send(struct clk_rpmh *c, enum rpmh_state state, > + struct tcs_cmd *cmd, bool wait_for_completion) > +{ > + int ret; > + > + if (wait_for_completion) > + ret = rpmh_write(c->dev, state, cmd, 1); > + else > + ret = rpmh_write_async(c->dev, state, cmd, 1); > + > + return ret; > +} > + > static int clk_rpmh_send_aggregate_command(struct clk_rpmh *c) > { > struct tcs_cmd cmd = { 0 }; > @@ -159,7 +172,8 @@ static int clk_rpmh_send_aggregate_command(struct clk_rpmh *c) > if (cmd_state & BIT(state)) > cmd.data = on_val; > > - ret = rpmh_write_async(c->dev, state, &cmd, 1); > + ret = clk_rpmh_send(c, state, &cmd, > + cmd_state && state == RPMH_ACTIVE_ONLY_STATE); > if (ret) { > dev_err(c->dev, "set %s state of %s failed: (%d)\n", > !state ? "sleep" : > @@ -267,7 +281,7 @@ static int clk_rpmh_bcm_send_cmd(struct clk_rpmh *c, bool enable) > cmd.addr = c->res_addr; > cmd.data = BCM_TCS_CMD(1, enable, 0, cmd_state); > > - ret = rpmh_write_async(c->dev, RPMH_ACTIVE_ONLY_STATE, &cmd, 1); > + ret = clk_rpmh_send(c, RPMH_ACTIVE_ONLY_STATE, &cmd, enable); > if (ret) { > dev_err(c->dev, "set active state of %s failed: (%d)\n", > c->res_name, ret); > -- > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > a Linux Foundation Collaborative Project