From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from vsmx011.vodafonemail.xion.oxcs.net ([153.92.174.89]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jpvjq-0003xg-7m for barebox@lists.infradead.org; Mon, 29 Jun 2020 15:30:38 +0000 Date: Mon, 29 Jun 2020 17:30:19 +0200 (CEST) From: Giorgio Dal Molin Message-ID: <429834562.114102.1593444620511@mail.vodafone.de> In-Reply-To: <595dc8c8-09c8-81ad-d730-23781e207cbd@pengutronix.de> References: <925732743.424285.1592919941556@mail.vodafone.de> <245646662.425432.1592925096458@mail.vodafone.de> <517310923.70062.1593427992397@mail.vodafone.de> <595dc8c8-09c8-81ad-d730-23781e207cbd@pengutronix.de> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: reset / watchdog on an imx7d soc To: Ahmad Fatoum , Fabio Estevam Cc: Barebox List Hi, > On June 29, 2020 at 3:30 PM Ahmad Fatoum wrote: > > > Hello, > > On 6/29/20 12:53 PM, Giorgio Dal Molin wrote: > > Hi, > > > >> On June 29, 2020 at 10:44 AM Ahmad Fatoum wrote: > >> > >> > >> Hello Giorgio, > >> > >> On 6/23/20 5:11 PM, Giorgio Dal Molin wrote: > >>> Hi Fabio, > >>> > >>> thank you for your quick reply. > >>> > >>> I've already found the errata you linked in your mail but I had no success > >>> applying the suggestion there; maybe I'm doing it wrong. > >>> Let's take the Option 3 there: > >> > >> Does reset within Linux (with say the imx_v6_v7_defconfg) work? > > > > No. I see the same behavior also with the kernel: after a 'shutdown -r' > > the system 'goes down' but doesn't reboot, it just hang: > > > > ~ # shutdown -r > > system is going down for reboot NOW > > ... > > [ 46.248222] 000: ci_hdrc ci_hdrc.0: remove, state 1 > > [ 46.248253] 000: usb usb1: USB disconnect, device number 1 > > [ 46.248263] 000: usb 1-1: USB disconnect, device number 2 > > > > > > The same happens if I kill the 'watchdog' process: after ~2 seconds > > the system just hangs. > > > > I'm sure there must be a solution because the original u-boot bootloader > > for the cpu module I'm using reboots the system as expected, through the wdog1; > > unfortunately it's not so trivial to find what makes the difference. > > Linux probably attempts reset via PSCI. Check for psci_system_reset > in your vendor's U-Boot and transplant it into barebox. U-Boot has actually a psci_system_reset(), it also rely on wdog1: __secure void psci_system_reset(void) { struct wdog_regs *wdog = (struct wdog_regs *)WDOG1_BASE_ADDR; /* make sure WDOG1 clock is enabled */ writel(0x1 << 28, CCM_BASE_ADDR + CCM_ROOT_WDOG); writel(0x3, CCM_BASE_ADDR + CCM_CCGR_WDOG1); writew(WCR_WDE, &wdog->wcr); while (1) wfi(); } It is also compiled in the uboot image, because if I add a syntax error in its body the compiler tells me; anyway I think it's not called when I issue the 'reset' command at the prompt because the 'reset' works properly even if I comment out the whole body of the function or if I add an endless loop like while(1); to it. Anyway I ported it to barebox, defining a void psci_system_reset(void) in arch/arm/mach-imx/imx7.c: ... #define CCM_BASE_ADDR 0x30380000 #define CCM_ROOT_WDOG 0xbb80 #define CCM_CCGR_WDOG1 0x49c8 #define WCR_WDE 0x04 #define WDOG1_WCR 0x30280000 #define wfi() __asm__ __volatile__ ("wfi" : : : "memory") static void imx7_system_reset(void) { printf("%s: called now.\n",__func__); // make sure WDOG1 clock is enabled writel(0x1 << 28, CCM_BASE_ADDR + CCM_ROOT_WDOG); writel(0x3, CCM_BASE_ADDR + CCM_CCGR_WDOG1); writew(WCR_WDE, WDOG1_WCR); while (1) wfi(); }; static struct psci_ops imx7_psci_ops = { .cpu_on = imx7_cpu_on, .cpu_off = imx7_cpu_off, .system_reset = imx7_system_reset, }; and the following case to smc.c: static int do_smc(int argc, char *argv[]) { ... case 'r': printf("issue psci reset...\n"); arm_smccc_smc(ARM_PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0, 0, 0, 0, 0, &res); printf("reset issued...\n"); break; ... to be able to call it. Now, using the modified 'smc' command I can see my printf's: samx7: / smc -n samx7: / smc -r issue psci reset... psci_system_reset called. imx7_system_reset: called now. but the soc still just hangs. giorgio > > > > > giorgio > > > > > >> > >> -- > >> 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 | > >> > >> _______________________________________________ > >> barebox mailing list > >> barebox@lists.infradead.org > >> http://lists.infradead.org/mailman/listinfo/barebox > > > > -- > 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 | > > _______________________________________________ > barebox mailing list > barebox@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/barebox _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox