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,USER_AGENT_SANE_1 autolearn=unavailable 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 5C20CC4332B for ; Fri, 20 Mar 2020 10:35:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2885C2072D for ; Fri, 20 Mar 2020 10:35:30 +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="NVaCJNc6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726955AbgCTKf3 (ORCPT ); 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Fri, 20 Mar 2020 10:35:17 -0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id A5057C432C2; Fri, 20 Mar 2020 10:35:15 +0000 (UTC) Received: from [192.168.0.13] (unknown [183.83.138.47]) (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 B5CCAC433D2; Fri, 20 Mar 2020 10:35:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org B5CCAC433D2 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 V2 4/8] tty: serial: qcom_geni_serial: Add interconnect support 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 References: <1584105134-13583-1-git-send-email-akashast@codeaurora.org> <1584105134-13583-5-git-send-email-akashast@codeaurora.org> <20200313212833.GK144492@google.com> <20200317190804.GS144492@google.com> <20200319204248.GA204494@google.com> From: Akash Asthana Message-ID: Date: Fri, 20 Mar 2020 16:05:06 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200319204248.GA204494@google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit 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 3/20/2020 2:12 AM, Matthias Kaehlcke wrote: > On Wed, Mar 18, 2020 at 05:53:22PM +0530, Akash Asthana wrote: >> Hi Matthias, >> >> On 3/18/2020 12:38 AM, Matthias Kaehlcke wrote: >>> On Tue, Mar 17, 2020 at 05:18:34PM +0530, Akash Asthana wrote: >>>> Hi Matthias, >>>> >>>> On 3/14/2020 2:58 AM, Matthias Kaehlcke wrote: >>>>> Hi Akash, >>>>> >>>>> On Fri, Mar 13, 2020 at 06:42:10PM +0530, Akash Asthana wrote: >>>>>> Get the interconnect paths for Uart based Serial Engine device >>>>>> and vote according to the baud rate requirement of the driver. >>>>>> >>>>>> Signed-off-by: Akash Asthana >>>>>> --- >>>>>> Changes in V2: >>>>>> - As per Bjorn's comment, removed se == NULL check from geni_serial_icc_get >>>>>> - As per Bjorn's comment, removed code to set se->icc_path* to NULL in failure >>>>>> - As per Bjorn's comment, introduced and using devm_of_icc_get API for getting >>>>>> path handle >>>>>> - As per Matthias comment, added error handling for icc_set_bw call >>>>>> >>>>>> drivers/tty/serial/qcom_geni_serial.c | 69 +++++++++++++++++++++++++++++++++-- >>>>>> 1 file changed, 65 insertions(+), 4 deletions(-) >>>>>> >>>>>> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c >>>>>> index 272bae0..c8ad7e9 100644 >>>>>> --- a/drivers/tty/serial/qcom_geni_serial.c >>>>>> +++ b/drivers/tty/serial/qcom_geni_serial.c >>>>>> >>>>>> ... >>>>>> >>>>>> static int qcom_geni_serial_request_port(struct uart_port *uport) >>>>>> { >>>>>> struct platform_device *pdev = to_platform_device(uport->dev); >>>>>> @@ -962,6 +975,7 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport, >>>>>> struct qcom_geni_serial_port *port = to_dev_port(uport, uport); >>>>>> unsigned long clk_rate; >>>>>> u32 ver, sampling_rate; >>>>>> + int ret; >>>>>> qcom_geni_serial_stop_rx(uport); >>>>>> /* baud rate */ >>>>>> @@ -983,6 +997,18 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport, >>>>>> ser_clk_cfg = SER_CLK_EN; >>>>>> ser_clk_cfg |= clk_div << CLK_DIV_SHFT; >>>>>> + /* >>>>>> + * Put BW vote only on CPU path as driver supports FIFO mode only. >>>>>> + * Assume peak_bw as twice of avg_bw. >>>>>> + */ >>>>>> + port->se.avg_bw_cpu = Bps_to_icc(baud); >>>>>> + port->se.peak_bw_cpu = Bps_to_icc(2 * baud); >>>>>> + ret = icc_set_bw(port->se.icc_path_cpu_to_geni, port->se.avg_bw_cpu, >>>>>> + port->se.peak_bw_cpu); >>>>>> + if (ret) >>>>>> + dev_err(uport->dev, "%s: ICC BW voting failed for cpu\n", >>>>>> + __func__); >>>>> Should this return an error? The port might not operate properly if the ICC >>>>> bandwidth couldn't be configured >>>> This is void function we can't return error from here. I guess it would be >>>> somewhat okay if BW voting failed for CPU path but clk_set_rate failure is >>>> more serious which is called from this function, I don't think it can be >>>> move to somewhere else. >>> ok, I missed that _set_termios() is void. >>> >>>>>> static const struct uart_ops qcom_geni_console_pops = { >>>>>> @@ -1308,6 +1358,17 @@ static int qcom_geni_serial_probe(struct platform_device *pdev) >>>>>> port->rx_fifo_depth = DEF_FIFO_DEPTH_WORDS; >>>>>> port->tx_fifo_width = DEF_FIFO_WIDTH_BITS; >>>>>> + ret = geni_serial_icc_get(&port->se); >>>>>> + if (ret) >>>>>> + return ret; >>>>>> + /* Set the bus quota to a reasonable value */ >>>>>> + port->se.avg_bw_core = console ? Bps_to_icc(1000) : >>>>>> + Bps_to_icc(CORE_2X_50_MHZ); >>>>> Why different settings for console vs. non-console? >>>> QUP FW runs on core clock. To support higher throughput we want FW to run at >>>> higher speed. >>>> >>>> Since Console operate at 115200bps and BT operate at 3.2Mbps baud. We are >>>> voting higher on core for BT usecase. >>>> >>>> These value are recommended from HW team. >>> IIUC none of the values you mention are set in stone. 115200bps seems to be a >>> 'standard' value for the serial console, but it could be a different baudrate. >>> I guess you are referring to Qualcomm Bluetooth controllers, which are only one >>> of many things that could be connected to the port. And what happens when a >>> QCA BT controller is connected to a non-geni/QCA port, which doesn't know about >>> its 'requirements'? The answer is that both the BT controller and the serial >>> console configure the baudrate they need, hence using different values in >>> _probe() is pointless. >> Are you refering other UART drivers(not based on geni HW) as non-geni/QCA >> port? >> >> We are not scaling core BW request based on real time need like we are doing >> for other paths(CPU/DDR) instead we are using some fail proof value because, >> FW runs on core clock and core behaves a bit different than other NOCs. >> >> We don't have any functional relation which maps actual throughput >> requirement to core frequency need. In the past we faced few latency issues >> because of core slowness (Although it was running much higher than actual >> throughput requirement). To avoid such scenario we are using recommend value >> from HW team. These fix value can support SE drivers operating at their max >> possible speed(4Mbps in case of non-console). > ok, I missed that the core clocks aren't scaled based on the configured > baudrate. Apparently experience shows that it is not practical due to the > latency issues you mention. Yeah That is correct. >> I agree that 115200bps seems to be a 'standard' value for the serial >> console, but it could be a different baudrate. >> >> We are voting 1000 in case of console because it  has low power mode >> use-case in android, where voting CORE_2X_50_MHZ can be reported as a power >> issue. >> >> Actually we wanted to vote 960 for console but that is not possible with >> current ICC design where the minimum value is 1000bps.  So any way core is >> running at 50 MHz as 1000 crosses the threshold for 19.2 MHz (960) >> >> only with console. > Thanks for the clarification. So if a board wanted to use a higher baudrate > for the console it (currently) shouldn't be a problem. While it would be nice > to have uniform settings for all UARTs it's also not a big deal to have two > values, just wanted to make sure it's needed Okay, but I would like to keep as it is with above mentioned reason. Thanks, Akash -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,\na Linux Foundation Collaborative Project From mboxrd@z Thu Jan 1 00:00:00 1970 From: Akash Asthana Subject: Re: [PATCH V2 4/8] tty: serial: qcom_geni_serial: Add interconnect support Date: Fri, 20 Mar 2020 16:05:06 +0530 Message-ID: References: <1584105134-13583-1-git-send-email-akashast@codeaurora.org> <1584105134-13583-5-git-send-email-akashast@codeaurora.org> <20200313212833.GK144492@google.com> <20200317190804.GS144492@google.com> <20200319204248.GA204494@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20200319204248.GA204494-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> Content-Language: en-US Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Matthias Kaehlcke Cc: gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, agross-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, bjorn.andersson-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org, broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, swboyd-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, mgautam-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, evgreen-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org List-Id: linux-i2c@vger.kernel.org Hi Matthias, On 3/20/2020 2:12 AM, Matthias Kaehlcke wrote: > On Wed, Mar 18, 2020 at 05:53:22PM +0530, Akash Asthana wrote: >> Hi Matthias, >> >> On 3/18/2020 12:38 AM, Matthias Kaehlcke wrote: >>> On Tue, Mar 17, 2020 at 05:18:34PM +0530, Akash Asthana wrote: >>>> Hi Matthias, >>>> >>>> On 3/14/2020 2:58 AM, Matthias Kaehlcke wrote: >>>>> Hi Akash, >>>>> >>>>> On Fri, Mar 13, 2020 at 06:42:10PM +0530, Akash Asthana wrote: >>>>>> Get the interconnect paths for Uart based Serial Engine device >>>>>> and vote according to the baud rate requirement of the driver. >>>>>> >>>>>> Signed-off-by: Akash Asthana >>>>>> --- >>>>>> Changes in V2: >>>>>> - As per Bjorn's comment, removed se == NULL check from geni_serial_icc_get >>>>>> - As per Bjorn's comment, removed code to set se->icc_path* to NULL in failure >>>>>> - As per Bjorn's comment, introduced and using devm_of_icc_get API for getting >>>>>> path handle >>>>>> - As per Matthias comment, added error handling for icc_set_bw call >>>>>> >>>>>> drivers/tty/serial/qcom_geni_serial.c | 69 +++++++++++++++++++++++++++++++++-- >>>>>> 1 file changed, 65 insertions(+), 4 deletions(-) >>>>>> >>>>>> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c >>>>>> index 272bae0..c8ad7e9 100644 >>>>>> --- a/drivers/tty/serial/qcom_geni_serial.c >>>>>> +++ b/drivers/tty/serial/qcom_geni_serial.c >>>>>> >>>>>> ... >>>>>> >>>>>> static int qcom_geni_serial_request_port(struct uart_port *uport) >>>>>> { >>>>>> struct platform_device *pdev = to_platform_device(uport->dev); >>>>>> @@ -962,6 +975,7 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport, >>>>>> struct qcom_geni_serial_port *port = to_dev_port(uport, uport); >>>>>> unsigned long clk_rate; >>>>>> u32 ver, sampling_rate; >>>>>> + int ret; >>>>>> qcom_geni_serial_stop_rx(uport); >>>>>> /* baud rate */ >>>>>> @@ -983,6 +997,18 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport, >>>>>> ser_clk_cfg = SER_CLK_EN; >>>>>> ser_clk_cfg |= clk_div << CLK_DIV_SHFT; >>>>>> + /* >>>>>> + * Put BW vote only on CPU path as driver supports FIFO mode only. >>>>>> + * Assume peak_bw as twice of avg_bw. >>>>>> + */ >>>>>> + port->se.avg_bw_cpu = Bps_to_icc(baud); >>>>>> + port->se.peak_bw_cpu = Bps_to_icc(2 * baud); >>>>>> + ret = icc_set_bw(port->se.icc_path_cpu_to_geni, port->se.avg_bw_cpu, >>>>>> + port->se.peak_bw_cpu); >>>>>> + if (ret) >>>>>> + dev_err(uport->dev, "%s: ICC BW voting failed for cpu\n", >>>>>> + __func__); >>>>> Should this return an error? The port might not operate properly if the ICC >>>>> bandwidth couldn't be configured >>>> This is void function we can't return error from here. I guess it would be >>>> somewhat okay if BW voting failed for CPU path but clk_set_rate failure is >>>> more serious which is called from this function, I don't think it can be >>>> move to somewhere else. >>> ok, I missed that _set_termios() is void. >>> >>>>>> static const struct uart_ops qcom_geni_console_pops = { >>>>>> @@ -1308,6 +1358,17 @@ static int qcom_geni_serial_probe(struct platform_device *pdev) >>>>>> port->rx_fifo_depth = DEF_FIFO_DEPTH_WORDS; >>>>>> port->tx_fifo_width = DEF_FIFO_WIDTH_BITS; >>>>>> + ret = geni_serial_icc_get(&port->se); >>>>>> + if (ret) >>>>>> + return ret; >>>>>> + /* Set the bus quota to a reasonable value */ >>>>>> + port->se.avg_bw_core = console ? Bps_to_icc(1000) : >>>>>> + Bps_to_icc(CORE_2X_50_MHZ); >>>>> Why different settings for console vs. non-console? >>>> QUP FW runs on core clock. To support higher throughput we want FW to run at >>>> higher speed. >>>> >>>> Since Console operate at 115200bps and BT operate at 3.2Mbps baud. We are >>>> voting higher on core for BT usecase. >>>> >>>> These value are recommended from HW team. >>> IIUC none of the values you mention are set in stone. 115200bps seems to be a >>> 'standard' value for the serial console, but it could be a different baudrate. >>> I guess you are referring to Qualcomm Bluetooth controllers, which are only one >>> of many things that could be connected to the port. And what happens when a >>> QCA BT controller is connected to a non-geni/QCA port, which doesn't know about >>> its 'requirements'? The answer is that both the BT controller and the serial >>> console configure the baudrate they need, hence using different values in >>> _probe() is pointless. >> Are you refering other UART drivers(not based on geni HW) as non-geni/QCA >> port? >> >> We are not scaling core BW request based on real time need like we are doing >> for other paths(CPU/DDR) instead we are using some fail proof value because, >> FW runs on core clock and core behaves a bit different than other NOCs. >> >> We don't have any functional relation which maps actual throughput >> requirement to core frequency need. In the past we faced few latency issues >> because of core slowness (Although it was running much higher than actual >> throughput requirement). To avoid such scenario we are using recommend value >> from HW team. These fix value can support SE drivers operating at their max >> possible speed(4Mbps in case of non-console). > ok, I missed that the core clocks aren't scaled based on the configured > baudrate. Apparently experience shows that it is not practical due to the > latency issues you mention. Yeah That is correct. >> I agree that 115200bps seems to be a 'standard' value for the serial >> console, but it could be a different baudrate. >> >> We are voting 1000 in case of console because it  has low power mode >> use-case in android, where voting CORE_2X_50_MHZ can be reported as a power >> issue. >> >> Actually we wanted to vote 960 for console but that is not possible with >> current ICC design where the minimum value is 1000bps.  So any way core is >> running at 50 MHz as 1000 crosses the threshold for 19.2 MHz (960) >> >> only with console. > Thanks for the clarification. So if a board wanted to use a higher baudrate > for the console it (currently) shouldn't be a problem. While it would be nice > to have uniform settings for all UARTs it's also not a big deal to have two > values, just wanted to make sure it's needed Okay, but I would like to keep as it is with above mentioned reason. Thanks, Akash -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,\na Linux Foundation Collaborative Project