From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Mon, 14 Apr 2025 13:16:33 +0200 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1u4Hnl-000cQy-24 for lore@lore.pengutronix.de; Mon, 14 Apr 2025 13:16:33 +0200 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1u4Hnk-0003hM-Rt for lore@pengutronix.de; Mon, 14 Apr 2025 13:16:33 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=35aT6u9bKJvJJ6zHeZ2lX6wnf2PohI5JDianjtFbbPQ=; b=yaZumD9gq0lH4eKw+eUnBL1e9x gzL8x01CVHd0Mc7LpbI7bpw8H25M6XqdFG3W/8MZBAt3K6DtH6ORpulvoUi6jTRQN340Tzdjzqq3n ocISvZ6xH4p9BNXw6fnfNGXB8Ax4aPZ1zM14Hw19a7LkewwHJ3SpcLX7q8r0qb+YemDMzv2fpGdF7 weFnJeSIff9yUe6gGDatYeKobEueTX0bgPoyqQorWoLlPwTfbadYSf95NAhLMGJHpYegJd82vACMx fPWij+3orN+ibTXfDtJnP4qKoyq7Zs3VLLtbeZ7OR96hGcfIqUtY2h3l9snGlWj+vVyisEp8ZuH++ /jCrtWRg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u4HnH-00000001ihc-2XtZ; Mon, 14 Apr 2025 11:16:03 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1u4Hic-00000001gqv-1nMw for barebox@lists.infradead.org; Mon, 14 Apr 2025 11:11:16 +0000 Received: from ptz.office.stw.pengutronix.de ([2a0a:edc0:0:900:1d::77] helo=[127.0.0.1]) by metis.whiteo.stw.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1u4Hib-0001XB-46; Mon, 14 Apr 2025 13:11:13 +0200 Message-ID: Date: Mon, 14 Apr 2025 13:11:12 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Marco Felsch Cc: barebox@lists.infradead.org, Kim Christensen , Oleksij Rempel References: <20250414065009.2770749-1-a.fatoum@pengutronix.de> <20250414065009.2770749-4-a.fatoum@pengutronix.de> <20250414084043.j5v2xjh2bnadoicc@pengutronix.de> <20250414092134.glztg7o6nqqsxqdr@pengutronix.de> <7161d8ec-3f19-4504-b9f5-03b512c4f84d@pengutronix.de> <20250414105638.uxzlbcigm765uyyg@pengutronix.de> From: Ahmad Fatoum Content-Language: en-US, de-DE, de-BE In-Reply-To: <20250414105638.uxzlbcigm765uyyg@pengutronix.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250414_041114_478453_B8C5014A X-CRM114-Status: GOOD ( 27.53 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-5.2 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH 4/6] ARM: i.MX8MP: skov: halt startup until power is good X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) Hello Marco, On 4/14/25 12:56, Marco Felsch wrote: > On 25-04-14, Ahmad Fatoum wrote: >> Hello Marco, >> >> On 14.04.25 11:21, Marco Felsch wrote: >>> On 25-04-14, Ahmad Fatoum wrote: >>>> Hello Marco, >>>> >>>> On 14.04.25 10:40, Marco Felsch wrote: >>>>> Hi, >>>>> >>>>> On 25-04-14, Ahmad Fatoum wrote: >>>>>> The 24V regulator supplying the system can indicate via a GPIO imminent >>>>>> voltage loss. The board's capacitors hold enough charge to power the system >>>>>> a while longer in such a state, but eventually, unless external power is >>>>>> restored, the brownout detection of the PMIC will kick in. >>>>>> >>>>>> For the span of time between voltage drop detection and PMIC brownout, >>>>>> let's detect this situation and delay startup. This way, Linux can >>>>>> detect the ongoing voltage loss, power down the eMMC, reboot into >>>>>> barebox and barebox will delay boot as long as the problem persists. >>>>>> >>>>>> Co-developed-by: Kim Christensen >>>>>> Signed-off-by: Ahmad Fatoum >>>>>> --- >>>>>> arch/arm/boards/skov-imx8mp/lowlevel.c | 60 ++++++++++++++++++++++++++ >>>>>> 1 file changed, 60 insertions(+) >>>>>> >>>>>> diff --git a/arch/arm/boards/skov-imx8mp/lowlevel.c b/arch/arm/boards/skov-imx8mp/lowlevel.c >>>>>> index 637fc50b3f30..d7bd771f259d 100644 >>>>>> --- a/arch/arm/boards/skov-imx8mp/lowlevel.c >>>>>> +++ b/arch/arm/boards/skov-imx8mp/lowlevel.c >>>>>> @@ -20,6 +20,9 @@ >>>>>> >>>>>> extern char __dtb_z_imx8mp_skov_start[]; >>>>>> >>>>>> +#define PGOOD_PAD_CTRL MUX_PAD_CTRL(MX8MP_PAD_CTL_PUE | \ >>>>>> + MX8MP_PAD_CTL_PE) >>>>>> + >>>>>> #define UART_PAD_CTRL MUX_PAD_CTRL(MX8MP_PAD_CTL_DSE6 | \ >>>>>> MX8MP_PAD_CTL_FSEL | \ >>>>>> MX8MP_PAD_CTL_PUE | \ >>>>>> @@ -30,6 +33,12 @@ extern char __dtb_z_imx8mp_skov_start[]; >>>>>> MX8MP_PAD_CTL_PUE | \ >>>>>> MX8MP_PAD_CTL_PE) >>>>>> >>>>>> +static inline void led_d1_toggle(bool *on) >>>>>> +{ >>>>>> + imx8m_gpio_direction_output(IOMEM(MX8MP_GPIO1_BASE_ADDR), 5, *on); >>>>>> + *on = !*on; >>>>>> +} >>>>>> + >>>>>> static void setup_uart(void) >>>>>> { >>>>>> void __iomem *uart = IOMEM(MX8M_UART2_BASE_ADDR); >>>>>> @@ -67,6 +76,55 @@ static struct pmic_config pca9450_cfg[] = { >>>>>> { PCA9450_BUCK2OUT_DVS0, 0x14 }, >>>>>> }; >>>>>> >>>>>> +static inline bool power_good(void) >>>>>> +{ >>>>>> + /* IMX_SHDN_MF in schematics */ >>>>>> + return imx8m_gpio_val(IOMEM(MX8MP_GPIO4_BASE_ADDR), 23); >>>>>> +} >>>>>> + >>>>>> +static void wait_for_power_good(void) >>>>>> +{ >>>>>> + void __iomem *gpio4 = IOMEM(MX8MP_GPIO4_BASE_ADDR); >>>>>> + int timeout_ms = 0; >>>>>> + bool led_active = true; >>>>>> + >>>>>> + imx8mp_setup_pad(MX8MP_PAD_SAI2_RXD0__GPIO4_IO23 | PGOOD_PAD_CTRL); >>>>>> + imx8m_gpio_direction_input(gpio4, 23); >>>>>> + >>>>>> + led_d1_toggle(&led_active); >>>>>> + >>>>>> + if (power_good()) >>>>>> + return; >>>>>> + >>>>>> + pr_warn("\nDelaying boot until power stabilizes\n"); >>>>>> + >>>>>> + /* If we reach this, because Linux did a hw_protection_reboot, we don't >>>>>> + * want to continue booting right away. >>>>>> + * >>>>>> + * Thus let's either wait for the condition to subscede or for voltage >>>>>> + * to reach a low enough level for the PMIC to detect VSYS_UVLO going >>>>>> + * lower than allowed >>>>>> + */ >>>>>> + >>>>>> + while (1) { >>>>>> + if (power_good()) { >>>>>> + /* wait 10ms longer and check if it still good */ >>>>>> + udelay(10000); >>>>>> + if (power_good()) { >>>>>> + pr_info("IMX_SHDN_MF stuck low for ~%ums.\n", timeout_ms); >>>>>> + break; >>>>>> + } >>>>>> + } >>>>>> + /* fast blink LED D1 */ >>>>>> + if (timeout_ms % 100 == 0) { >>>>>> + pr_debug("."); >>>>>> + led_d1_toggle(&led_active); >>>>>> + } >>>>>> + udelay(1000); >>>>>> + timeout_ms++; >>>>>> + } >>>>>> +} >>>>>> + >>>>>> static void power_init_board(void) >>>>>> { >>>>>> struct pbl_i2c *i2c; >>>>>> @@ -77,6 +135,8 @@ static void power_init_board(void) >>>>>> imx8mp_setup_pad(MX8MP_PAD_SAI3_TXD__GPIO5_IO01); >>>>>> imx8m_gpio_direction_output(IOMEM(MX8MP_GPIO5_BASE_ADDR), 1, 0); >>>>>> >>>>>> + wait_for_power_good(); >>>>> >>>>> out of curiosity, wouldn't it be more useful to do the check right >>>>> before the system wants to boot the kernel and abort in that case? >>>> >>>> How so? >>>> >>>> When we have brownout, we usually never make it out of the PBL, >>> >>> Okay, since your backup charge is really low already. >>> >>>> so I prefer the SoC gets powered off during this loop instead >>>> of during the RAM setup. >>> >>> I understand that to wait for the power to become good again, but what >>> if the power is getting good and changes to bad again once you entered >>> barebox? Do you get notified about such an event? >>> >>> IMHO the later point a bit more important since this ensures that the >>> system was in power-good state before we the system starts. >> >> Checking just before booting is insufficient anyway, because power good >> may fluctuate before the Linux driver starts taking care of the power >> good GPIO. Given that we need to handle this anyway, I don't think >> it makes much difference whether when we check the power good GPIO >> during barebox runtime. > > I know, but still it is good to check and to wait for power-good state > before you cont. booting. Like you do for barebox: you wait till the > power is good or die within the PBL. I will take note of this, so I can revisit it with Oleksij in the future. Thanks, Ahmad > > Regards, > Marco > > >> >> Cheers, >> Ahmad >> >>> >>> Regards, >>> Marco >>> >> >> >> -- >> Pengutronix e.K. | | >> Steuerwalder Str. 21 | http://www.pengutronix.de/ | >> 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | >> Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | >> > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |