From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Babic Date: Mon, 7 Dec 2015 15:24:36 +0100 Subject: [U-Boot] [PATCH] imx_common: check for Serial Downloader in spl_boot_device In-Reply-To: <566592F4.4090901@nelint.com> References: <1449219732-5396-1-git-send-email-sbabic@denx.de> <56634586.6050200@nelint.com> <5665579F.1080808@denx.de> <566592F4.4090901@nelint.com> Message-ID: <566596A4.4000703@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Eric, On 07/12/2015 15:08, Eric Nelson wrote: >> I agree with you, in fact it does not work - but I do not see a way to >> inform the ROM that next time it should run with USB as boot device. >> From the fusemap, I tried to set BOOT_CFG4 as 0x40 ("Reserved for serial >> ROM"), and fixing BOOT_CFG1 to 0x30, but it was only a try. In fact, we >> need to change BMODE from internal to serial, and I do not see a way in >> the "official" documentation. >> > > It doesn't help that all of this is undocumented :), but reverse- > engineering the bmode command :-) > > The "bmode usb" command sets gpr9 to 1, which isn't used for anything > else, so something like this will work: > > diff --git a/arch/arm/imx-common/spl.c b/arch/arm/imx-common/spl.c > index 28217d2..54f22e6 100644 > --- a/arch/arm/imx-common/spl.c > +++ b/arch/arm/imx-common/spl.c > @@ -26,8 +26,10 @@ u32 spl_boot_device(void) > * Check for BMODE if serial downloader is enabled > * BOOT_MODE - see IMX6DQRM Table 8-1 > */ > - if ((bmode >> 24) == 0x01) /* Serial Downloader */ > + if (((bmode >> 24) == 0x01) /* Serial Downloader */ > + || (gpr10_boot && (1 == reg))) > return BOOT_DEVICE_UART; > > AFAIK, there isn't any other way to get a value of 1 into GPR9, > so the test is safe. > This is a nice trick - I cannot see as well any combination for obtaining a 0x01 in GPR9. > Secondarily, since the low four bits are discarded in the switch(), > this prevents an almost-always-wrong interpretation of 1 as > OneNAND/NOR (I think there are very few if any i.MX6 boards using > OneNAND or NOR for boot). Agree. I add your proposal in V2, thanks ! Best regards, Stefano -- ===================================================================== DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de =====================================================================