From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 36A97C83000 for ; Tue, 28 Apr 2020 10:22:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0D93E206C0 for ; Tue, 28 Apr 2020 10:22:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="jvnMpYc0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727771AbgD1KWD (ORCPT ); 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Tue, 28 Apr 2020 10:22:01 -0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 519CBC432C2; Tue, 28 Apr 2020 10:22:01 +0000 (UTC) Received: from [192.168.43.98] (unknown [157.48.58.87]) (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 34FE7C433CB; Tue, 28 Apr 2020 10:21:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 34FE7C433CB 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 V4 4/9] 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, georgi.djakov@linaro.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 References: <1586946198-13912-1-git-send-email-akashast@codeaurora.org> <1586946198-13912-5-git-send-email-akashast@codeaurora.org> <20200416003112.GA199755@google.com> From: Akash Asthana Message-ID: <146cf8db-3c09-39a6-2886-bec0db289948@codeaurora.org> Date: Tue, 28 Apr 2020 15:51:44 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200416003112.GA199755@google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org Hi Matthias, On 4/16/2020 6:01 AM, Matthias Kaehlcke wrote: > Hi Akash, > > On Wed, Apr 15, 2020 at 03:53:13PM +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. >> >> drivers/soc/qcom/qcom-geni-se.c | 50 +++++++++++++++++++++++++++++++++++ >> drivers/tty/serial/qcom_geni_serial.c | 7 +++++ >> include/linux/qcom-geni-se.h | 2 ++ >> 3 files changed, 59 insertions(+) >> >> diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c >> index 1527bc4..727ad2e 100644 >> --- a/drivers/soc/qcom/qcom-geni-se.c >> +++ b/drivers/soc/qcom/qcom-geni-se.c >> @@ -90,8 +90,11 @@ 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 struct geni_wrapper *earlycon_wrapper; >> + >> #define QUP_HW_VER_REG 0x4 >> >> /* Common SE registers */ >> @@ -781,6 +784,26 @@ int geni_icc_vote_off(struct geni_se *se) >> } >> EXPORT_SYMBOL(geni_icc_vote_off); >> >> +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); >> + 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; >> + } >> + } >> + 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; >> @@ -808,6 +831,33 @@ static int geni_se_probe(struct platform_device *pdev) >> } >> } >> >> +#ifdef CONFIG_SERIAL_EARLYCON >> + 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, 0); >> + if (ret) { >> + dev_err(&pdev->dev, "%s: ICC BW voting failed for core\n", >> + __func__); >> + return ret; >> + } >> + >> + if (of_get_compatible_child(pdev->dev.of_node, "qcom,geni-debug-uart")) >> + earlycon_wrapper = wrapper; >> + of_node_put(pdev->dev.of_node); >> +#endif >> + >> dev_set_drvdata(dev, wrapper); >> dev_dbg(dev, "GENI SE Driver probed\n"); >> return devm_of_platform_populate(dev); >> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c >> index 6119090..8c5d97c 100644 >> --- a/drivers/tty/serial/qcom_geni_serial.c >> +++ b/drivers/tty/serial/qcom_geni_serial.c >> @@ -1090,6 +1090,12 @@ static void qcom_geni_serial_earlycon_write(struct console *con, >> __qcom_geni_serial_console_write(&dev->port, s, n); >> } >> >> +static int qcom_geni_serial_earlycon_exit(struct console *con) >> +{ >> + geni_remove_earlycon_icc_vote(); >> + return 0; >> +} >> + >> static int __init qcom_geni_serial_earlycon_setup(struct earlycon_device *dev, >> const char *opt) >> { >> @@ -1135,6 +1141,7 @@ static int __init qcom_geni_serial_earlycon_setup(struct earlycon_device *dev, >> writel(stop_bit_len, uport->membase + SE_UART_TX_STOP_BIT_LEN); >> >> dev->con->write = qcom_geni_serial_earlycon_write; >> + dev->con->exit = qcom_geni_serial_earlycon_exit; > The idea of using the exit handler of the early console to remove the > votes seemed appealing at first, however it has a drawback: the bandwidth > requests in geni_se_probe() are always made when CONFIG_SERIAL_EARLYCON=y, > also when the system doesn't actually use an early console. On such a > system the votes would never be removed. > > A possible alternative could seem to remove the vote at the end of > qcom_geni_serial_probe() of the 'normal' console, but it has a similar > problem: the system could not even have a normal console. One could > possibly argue that CONFIG_SERIAL_QCOM_GENI_CONSOLE shouldn't be set > on such a system, however it could be enabled to have a console for > development, and in production the same kernel config is used, but > with the console disabled through the device tree. > > I don't really have a good idea at this point, maybe we just need > something as ugly as a delayed work to remove the votes. Other > suggestions are welcome :) I think we can do something like below. Before voting we are checking whether earlyconsole ("qcom_geni") exits or not.  The name is fixed from earlycon declaration file@drivers/tty/serial/qcom_geni_serial.c OF_EARLYCON_DECLARE(qcom_geni, "qcom,geni-debug-uart",                                 qcom_geni_serial_earlycon_setup); ==================================================================================== @@ -809,6 +809,8 @@ static int geni_se_probe(struct platform_device *pdev)         struct device *dev = &pdev->dev;         struct resource *res;         struct geni_wrapper *wrapper; +       struct console *bcon = NULL; +       int earlycon_present = 0;         int ret;         wrapper = devm_kzalloc(dev, sizeof(*wrapper), GFP_KERNEL); @@ -832,6 +834,15 @@ static int geni_se_probe(struct platform_device *pdev)         }  #ifdef CONFIG_SERIAL_EARLYCON +       if (console_drivers) +               for_each_console(bcon) +                       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); @@ -858,6 +869,7 @@ static int geni_se_probe(struct platform_device *pdev)         of_node_put(pdev->dev.of_node);  #endif +exit:         dev_set_drvdata(dev, wrapper);         dev_dbg(dev, "GENI SE Driver probed\n");         return devm_of_platform_populate(dev); ====================================================================================== Regards, Akash -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,\na Linux Foundation Collaborative Project