From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Mon, 14 Apr 2025 11:07:32 +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 1u4Fmu-000Zu8-0j for lore@lore.pengutronix.de; Mon, 14 Apr 2025 11:07:32 +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 1u4Fmt-0007tw-6k for lore@pengutronix.de; Mon, 14 Apr 2025 11:07:32 +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=pVzVKk+rre0uLEaslVQB9j8h5GECh+uEjm5xmKibNro=; b=vXvubfXBuvBKHl2n1M5IiXxLdK I6q0IM94RKvCYm/8PUjSbOZoZUjwg6EGCbBCjOrbj9A+f2nguAmFtttgnqm3/15WhTJNRYkhN3OCX tgkq+IhsZmVDaXkUQeyRyLRSeWGJGY8Ds4kR5pCC9NqPm9z9u4i6+ZS/9cRnyxoomOPN1I5hL/nnJ JPxo+rUuoSwvKyAcmj7aRPaMk3VC7C6ZUptYzX+tI4UT+Kyl68HY2w5HZz81DHJE0whvTSY496L4m bRnHCMyR1cCA2kj4HItajs2ZUUDZfqcTseo0xZZUsy0Of9AjauCJ+rg8yUrUWKnAcU7k5nIyGmEbG Co4YI9vQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u4FmK-00000001DQP-0wXl; Mon, 14 Apr 2025 09:06:56 +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 1u4FSr-000000019zQ-1G9b for barebox@lists.infradead.org; Mon, 14 Apr 2025 08:46:50 +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 1u4FSq-0000qF-4U; Mon, 14 Apr 2025 10:46:48 +0200 Message-ID: Date: Mon, 14 Apr 2025 10:46:47 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Marco Felsch Cc: barebox@lists.infradead.org, Kim Christensen References: <20250414065009.2770749-1-a.fatoum@pengutronix.de> <20250414065009.2770749-4-a.fatoum@pengutronix.de> <20250414084043.j5v2xjh2bnadoicc@pengutronix.de> Content-Language: en-US From: Ahmad Fatoum In-Reply-To: <20250414084043.j5v2xjh2bnadoicc@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_014649_342359_45292AF5 X-CRM114-Status: GOOD ( 24.46 ) 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 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, so I prefer the SoC gets powered off during this loop instead of during the RAM setup. Cheers, ahmad > > Regards, > Marco > > >> + >> imx8mp_setup_pad(MX8MP_PAD_I2C1_SCL__I2C1_SCL | I2C_PAD_CTRL); >> imx8mp_setup_pad(MX8MP_PAD_I2C1_SDA__I2C1_SDA | I2C_PAD_CTRL); >> >> -- >> 2.39.5 >> >> >> > -- 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 |