From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gwCgw-00037s-Op for barebox@lists.infradead.org; Tue, 19 Feb 2019 21:12:40 +0000 Received: from gallifrey.ext.pengutronix.de ([2001:67c:670:201:5054:ff:fe8d:eefb] helo=a3f-osx.local) by metis.ext.pengutronix.de with esmtp (Exim 4.89) (envelope-from ) id 1gwCgv-00071h-8L for barebox@lists.infradead.org; Tue, 19 Feb 2019 22:12:37 +0100 References: <20190219120612.728-1-a.fatoum@pengutronix.de> <20190219120612.728-3-a.fatoum@pengutronix.de> <20190219204233.GA14204@ravnborg.org> <7820ced1-0a40-9bad-85ac-f3711161b96a@pengutronix.de> From: Ahmad Fatoum Message-ID: <11c78a49-dd9e-50bb-9781-81761672c2b5@pengutronix.de> Date: Tue, 19 Feb 2019 22:12:35 +0100 MIME-Version: 1.0 In-Reply-To: <7820ced1-0a40-9bad-85ac-f3711161b96a@pengutronix.de> Content-Language: en-US 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: [PATCH 2/4] ARM: at91: debug_ll: make UART base address configurable To: barebox@lists.infradead.org Hello, On 19/2/19 22:10, Ahmad Fatoum wrote: > Hello Sam, > > On 19/2/19 21:42, Sam Ravnborg wrote: >> Hi Ahmad. >> >> On Tue, Feb 19, 2019 at 01:06:10PM +0100, Ahmad Fatoum wrote: >>> This is in line with other platforms such as i.MX, which allow >>> specifying a debug port. As we can't use port indices because >>> the UARTs aren't mapped consecutively, allow specifying a hex >>> base at configuration time. >>> >>> A side effect of this patch is that sama5d4's HAVE_AT91_DBGU2 >>> is now honored as well. Previously anything besides DBGU0 >>> defaulted to DBGU1. >> >> This approch hardcoded the DBGU address based on the configuration. >> Can you somehow come up with something that is run-time configured? > > I think it should remain build-time configurable, to account for cases > such as when the designated debug port isn't usable for whatever reason > (e.g. its exposed via a USB-to-UART bridge and you want to use a proper > UART, because you hate that the disconnection on power cycle..). > > The hard coded values are just some often applicable defaults. > >> So we can continue towards the goal to have multi-image support >> for at91. >> The current approch will limit us to a single type of SOC - >> and we may try to combine more than one SOC in the same multi-iamge >> sometime in the future. >> >> Maybe each board have to call an debug_ll_init(address) function or similar. >> If not called we can use the default which is the common address >> for most at91 SOCs. > > It's a low level debug option, my understanding is that you only enable it > when one specific entry point fails to load on your board and you need some early > output to start debugging. > It shouldn't be kept on by default. Indeed only 6 defconfigs out of 126 ARM defconfigs > turn it on. (One of them my fresh microchip_ksz9477_evb_bootstrap_mmc_defconfig, oops..) Thinking about it, I think its ok to leave it on for a bootstrap defconfig. multi-image and size-constrained first stage bootloaders aren't a good mix anyway. > > For the general task of having a console in PBL, there is pbl_set_putc, > which boards code could configure. > >> Or maybe something smarter. >> >> Sam >> > -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 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