From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from vsmx012.vodafonemail.xion.oxcs.net ([153.92.174.90]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jpwGB-00060A-Uo for barebox@lists.infradead.org; Mon, 29 Jun 2020 16:03:57 +0000 Date: Mon, 29 Jun 2020 18:03:43 +0200 (CEST) From: Giorgio Dal Molin Message-ID: <1874617325.108865.1593446626706@mail.vodafone.de> In-Reply-To: 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> <429834562.114102.1593444620511@mail.vodafone.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 5:35 PM Ahmad Fatoum wrote: > > > Hello Giorgio, > > On 6/29/20 5:30 PM, Giorgio Dal Molin wrote: > > 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. > > Yes. It should be called by the kernel when CONFIG_ARM_PSCI_FW=y > and the device tree has the correct node. > > 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. > > What does U-Boot's reset commando do on an i.MX7? It ends up calling this function in the imx_watchdog.c: void __attribute__((weak)) reset_cpu(ulong addr) { struct watchdog_regs *wdog = (struct watchdog_regs *)WDOG1_BASE_ADDR; printf("%s: called now\n",__func__); udelay(500); clrsetbits_le16(&wdog->wcr, WCR_WT_MSK, WCR_WDE); writew(0x5555, &wdog->wsr); writew(0xaaaa, &wdog->wsr); /* load minimum 1/2 second timeout */ while (1) { /* * spin for .5 seconds before reset */ } } I added the printf / udelay to be sure. WCR_WT_MSK is (0xff << 8). What I also observed is that if I upload the uboot image with the imx-usb-loader it boots and runs normally but the reset in this case also just hangs the soc without rebooting it, like barebox; so there must be a difference between an 'usb uploaded' boot and a 'qspi native' boot. giorgio > > > > > 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 > > > > -- > 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