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Thu, 14 May 2020 06:45:54 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 1886DC43636; Thu, 14 May 2020 06:45:54 +0000 (UTC) Received: from [10.206.24.246] (blr-c-bdr-fw-01_GlobalNAT_AllZones-Outside.qualcomm.com [103.229.19.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: akashast) by smtp.codeaurora.org (Postfix) with ESMTPSA id A0AD8C433D2; Thu, 14 May 2020 06:45:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org A0AD8C433D2 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=akashast@codeaurora.org Subject: Re: [PATCH V5 2/7] soc: qcom-geni-se: Add interconnect support to fix earlycon crash To: Matthias Kaehlcke Cc: gregkh@linuxfoundation.org, agross@kernel.org, bjorn.andersson@linaro.org, wsa@the-dreams.de, broonie@kernel.org, mark.rutland@arm.com, robh+dt@kernel.org, linux-i2c@vger.kernel.org, linux-spi@vger.kernel.org, devicetree@vger.kernel.org, swboyd@chromium.org, mgautam@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-serial@vger.kernel.org, dianders@chromium.org, evgreen@chromium.org, georgi.djakov@linaro.org References: <1588919619-21355-1-git-send-email-akashast@codeaurora.org> <1588919619-21355-3-git-send-email-akashast@codeaurora.org> <20200508175938.GB4525@google.com> From: Akash Asthana Message-ID: <294b33e5-cf5a-8abc-2152-afa01664d962@codeaurora.org> Date: Thu, 14 May 2020 12:15:44 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200508175938.GB4525@google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Hi Matthias, On 5/8/2020 11:29 PM, Matthias Kaehlcke wrote: > Hi Akash, > > overall this looks good to me, a few comments inline > > On Fri, May 08, 2020 at 12:03:34PM +0530, Akash Asthana wrote: >> QUP core clock is shared among all the SE drivers present on particular >> QUP wrapper, the system will reset(unclocked access) if earlycon used after >> QUP core clock is put to 0 from other SE drivers before real console comes >> up. >> >> As earlycon can't vote for it's QUP core need, to fix this add ICC >> support to common/QUP wrapper driver and put vote for QUP core from >> probe on behalf of earlycon and remove vote during earlycon exit call. >> >> Signed-off-by: Akash Asthana >> Reported-by: Matthias Kaehlcke >> --- >> Change in V3: >> - Add geni_remove_earlycon_icc_vote API that will be used by earlycon >> exit function to remove ICC vote for earlyconsole. >> - Remove suspend/resume hook for geni-se driver as we are no longer >> removing earlyconsole ICC vote from system suspend, we are removing >> from earlycon exit. >> >> Change in V4: >> - As per Matthias comment make 'earlycon_wrapper' as static structure. >> >> Changes in V5: >> - Vote for core path only after checking whether "qcom_geni" earlycon is >> actually present or not by traversing over structure "console_drivers". >> >> drivers/soc/qcom/qcom-geni-se.c | 63 +++++++++++++++++++++++++++++++++++ >> drivers/tty/serial/qcom_geni_serial.c | 7 ++++ >> include/linux/qcom-geni-se.h | 2 ++ >> 3 files changed, 72 insertions(+) >> >> diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c >> index 63403bf..66fe6f2 100644 >> --- a/drivers/soc/qcom/qcom-geni-se.c >> +++ b/drivers/soc/qcom/qcom-geni-se.c >> @@ -3,6 +3,7 @@ >> >> #include >> #include >> +#include >> #include >> #include >> #include >> @@ -90,11 +91,14 @@ struct geni_wrapper { >> struct device *dev; >> void __iomem *base; >> struct clk_bulk_data ahb_clks[NUM_AHB_CLKS]; >> + struct geni_icc_path to_core; >> }; >> >> static const char * const icc_path_names[] = {"qup-core", "qup-config", >> "qup-memory"}; >> >> +static struct geni_wrapper *earlycon_wrapper; >> + >> #define QUP_HW_VER_REG 0x4 >> >> /* Common SE registers */ >> @@ -812,11 +816,33 @@ int geni_icc_disable(struct geni_se *se) >> } >> EXPORT_SYMBOL(geni_icc_disable); >> >> +void geni_remove_earlycon_icc_vote(void) >> +{ >> + struct geni_wrapper *wrapper = earlycon_wrapper; >> + struct device_node *parent = of_get_next_parent(wrapper->dev->of_node); > Do we need to check that earlycon_wrapper != NULL before dereferencing it? > In theory this should not happen, but better be safe. Ok, I will add NULL check. > >> + struct device_node *child; >> + >> + for_each_child_of_node(parent, child) { >> + if (of_device_is_compatible(child, "qcom,geni-se-qup")) { >> + wrapper = platform_get_drvdata(of_find_device_by_node( >> + child)); >> + icc_put(wrapper->to_core.path); >> + wrapper->to_core.path = NULL; > nit: setting the path to NULL isn't really needed IIUC. icc_put just free the path and don't reinitialize the path to NULL, if the path is used after it is put target will crash. So just for safety I am setting this path to NULL. > >> + } >> + } >> + of_node_put(parent); >> + >> + earlycon_wrapper = NULL; >> +} >> +EXPORT_SYMBOL(geni_remove_earlycon_icc_vote); >> + >> static int geni_se_probe(struct platform_device *pdev) >> { >> struct device *dev = &pdev->dev; >> struct resource *res; >> struct geni_wrapper *wrapper; >> + struct console *bcon; >> + int earlycon_present = 0; > use bool & true/false > > The variable is only used when CONFIG_SERIAL_EARLYCON is set, I think > you need to add '__maybe_unused' to avoid a compiler warning then earlycon > support is disabled. > > bikeshed: 'has_earlycon' would be slightly more concise (feel free to ignore). Ok > >> int ret; >> >> wrapper = devm_kzalloc(dev, sizeof(*wrapper), GFP_KERNEL); >> @@ -839,6 +865,43 @@ static int geni_se_probe(struct platform_device *pdev) >> } >> } >> >> +#ifdef CONFIG_SERIAL_EARLYCON >> + if (console_drivers) > The loop should have curly braces ("use braces when a loop contains more than > a single simple statement"), even though the compiler doesn't need them in > this case. This is not a loop, but I was told by a maintainer that it equally > applies, which makes sense. > > You could avoid one level of indentation through: Ok > > if (!console_drivers) > goto exit; I think I can omit this extra check because "for_each_console" will take care of this. > >> + for_each_console(bcon) > ditto (braces) > >> + if (!strcmp(bcon->name, "qcom_geni")) { >> + earlycon_present = 1; >> + break; >> + } >> + if (!earlycon_present) >> + goto exit; >> + >> + wrapper->to_core.path = devm_of_icc_get(dev, "qup-core"); >> + if (IS_ERR(wrapper->to_core.path)) >> + return PTR_ERR(wrapper->to_core.path); >> + /* >> + * Put minmal BW request on core clocks on behalf of early console. >> + * The vote will be removed earlycon exit function. >> + * >> + * Note: We are putting vote on each QUP wrapper instead only to which >> + * earlycon is connected because QUP core clock of different wrapper >> + * share same voltage domain. If core1 is put to 0, then core2 will >> + * also run at 0, if not voted. Default ICC vote will be removed ASA >> + * we touch any of the core clock. >> + * core1 = core2 = max(core1, core2) >> + */ >> + ret = icc_set_bw(wrapper->to_core.path, GENI_DEFAULT_BW, >> + GENI_DEFAULT_BW); > nit: the indentation is a bit odd. Align with 'wrapper->to_core.path' or a > nearby tab stop? ok Thanks for providing the feedback. Regards, Akash -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,\na Linux Foundation Collaborative Project