Hi Stefan, Eric, On 05/09/2017 06:50, Stefan Agner wrote: > On 2017-09-04 19:57, Eric Nelson wrote: >> Hi Stefan, >> >> On 09/04/2017 06:21 PM, Stefan Agner wrote: >>> From: Stefan Agner <stefan.ag...@toradex.com> >>> >>> This macro allows to detect whether the boot ROM initialized USB >>> already (serial downloader). This is helpful to reliably detect >>> if the system has been recovered via USB serial downloader. >>> >>> Signed-off-by: Stefan Agner <stefan.ag...@toradex.com> >>> Acked-by: Marcel Ziswiler <marcel.ziswi...@toradex.com> >>> --- >>> Hi Stefano, >>> >>> I noted already in my initial post that detection of serial >>> downloader mode is somewhat brittle: >>> https://lists.denx.de/pipermail/u-boot/2017-August/301952.html >>> >>> This came up quite fast now also for other boards: >>> https://www.mail-archive.com/u-boot@lists.denx.de/msg262234.html >>> >>> We use this patches since quite some time. Also NXP uses this >>> detection method to start their mfgr tools... Altough a hack, >>> maybe we should still add it upstream? >>> >>> -- >>> Stefan >>> >>> >>> arch/arm/include/asm/arch-mx6/imx-regs.h | 7 +++++++ >>> 1 file changed, 7 insertions(+) >>> >>> diff --git a/arch/arm/include/asm/arch-mx6/imx-regs.h >>> b/arch/arm/include/asm/arch-mx6/imx-regs.h >>> index 86e267087a..895ef4de83 100644 >>> --- a/arch/arm/include/asm/arch-mx6/imx-regs.h >>> +++ b/arch/arm/include/asm/arch-mx6/imx-regs.h >>> @@ -985,5 +985,12 @@ struct pwm_regs { >>> u32 pr; >>> u32 cnr; >>> }; >> >> It seems as if you've already named a constant, so you might as well >> #define and use it (USBPH0_PWD or USB0_PWD). > > Agreed. > >> >> The reference manual seems to call it RXPWDRX though. > > I guess taking the latest naming from the manual make sense. Will update > in v2. > > Before I send out v2, I'd like to know from Stefano whether he agrees > with the general direction of the patch. >
Green light from my side :-) > > >> >>> + >>> +/* >>> + * If ROM fell back to USB recover mode, USBPH0_PWD will be clear to use >>> USB >>> + * If boot from the other mode, USB0_PWD will keep reset value >>> + */ >>> +#define is_boot_from_usb(void) (!(readl(USB_PHY0_BASE_ADDR) & (1<<20))) >>> + >>> #endif /* __ASSEMBLER__*/ >>> #endif /* __ASM_ARCH_MX6_IMX_REGS_H__ */ >>> >> If I'm reading your comment correctly, the RXPWDRX bit will be set (the >> PHY will be powered down) unless it was enabled by the Boot ROM. >> >> Won't this also be clear if you've run 'usb start' under U-Boot? > > Yes, this only works before a USB initialization... > > This should be fine for the use case I have in mind (see patch 2). Agree. We want to detect just in SPL which was the (last) bootdevice and rather we cannot detect them from SCR/GPR that just reflect the configured booting device and not a fallback. > > Note this idea is borrowed from NXP downstream and seems to work here: > http://git.freescale.com/git/cgit.cgi/imx/uboot-imx.git/tree/arch/arm/include/asm/arch-mx7/imx-regs.h?h=imx_v2016.03_4.1.15_2.0.0_ga#n1204 > 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: sba...@denx.de ===================================================================== _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
