[U-Boot] [PATCH 1/2] arm: mvebu: fix boot from UART on ClearFog Base

[Baruch Siach]

Hi Stefan,

On Tue, Sep 19, 2017 at 06:48:59AM +0200, Stefan Roese wrote:
> On 18.09.2017 19:57, Baruch Siach wrote:
> > On Mon, Sep 18, 2017 at 06:00:23PM +0200, Stefan Roese wrote:
> > > On 20.08.2017 15:46, Baruch Siach wrote:
> > > > The ClearFog Base boot from UART when setting the DIP switches to 01001.
> > > > Unfortunately, the SPL code sometimes fails to detect the UART boot
> > > > method at run-time. Add an alternative SAR UART boot value to fix this.
> > > > 
> > > > Signed-off-by: Baruch Siach <baruch at tkos.co.il>
> > > > ---
> > > >    arch/arm/mach-mvebu/include/mach/soc.h | 1 +
> > > >    arch/arm/mach-mvebu/spl.c              | 1 +
> > > >    2 files changed, 2 insertions(+)
> > > > 
> > > > diff --git a/arch/arm/mach-mvebu/include/mach/soc.h b/arch/arm/mach-mvebu/include/mach/soc.h
> > > > index 0900e4008c12..44bac63b4447 100644
> > > > --- a/arch/arm/mach-mvebu/include/mach/soc.h
> > > > +++ b/arch/arm/mach-mvebu/include/mach/soc.h
> > > > @@ -139,6 +139,7 @@
> > > >    #define BOOT_DEV_SEL_MASK	(0x3f << BOOT_DEV_SEL_OFFS)
> > > >    #define BOOT_FROM_UART		0x28
> > > > +#define BOOT_FROM_UART_ALT	0x3f
> > > >    #define BOOT_FROM_SPI		0x32
> > > >    #define BOOT_FROM_MMC		0x30
> > > >    #define BOOT_FROM_MMC_ALT	0x31
> > > > diff --git a/arch/arm/mach-mvebu/spl.c b/arch/arm/mach-mvebu/spl.c
> > > > index 3cf02a54cea2..4b9c41360589 100644
> > > > --- a/arch/arm/mach-mvebu/spl.c
> > > > +++ b/arch/arm/mach-mvebu/spl.c
> > > > @@ -42,6 +42,7 @@ static u32 get_boot_device(void)
> > > >    		return BOOT_DEVICE_MMC1;
> > > >    #endif
> > > >    	case BOOT_FROM_UART:
> > > > +	case BOOT_FROM_UART_ALT:
> > > >    		return BOOT_DEVICE_UART;
> > > >    	case BOOT_FROM_SPI:
> > > >    	default:
> > > 
> > > This patch produces this error for some MVEBU boards:
> > > 
> > > [stefan at stefan-work u-boot-marvell (master)]$ make db-mv784mp-gp_defconfig
> > >    HOSTCC  scripts/basic/fixdep
> > >    HOSTCC  scripts/kconfig/conf.o
> > >    SHIPPED scripts/kconfig/zconf.tab.c
> > >    SHIPPED scripts/kconfig/zconf.lex.c
> > >    SHIPPED scripts/kconfig/zconf.hash.c
> > >    HOSTCC  scripts/kconfig/zconf.tab.o
> > >    HOSTLD  scripts/kconfig/conf
> > > #
> > > # configuration written to .config
> > > #
> > > [stefan at stefan-work u-boot-marvell (master)]$ make -s -j10
> > > arch/arm/mach-mvebu/spl.c: In function ‘get_boot_device’:
> > > arch/arm/mach-mvebu/spl.c:45:7: error: ‘BOOT_FROM_UART_ALT’ undeclared (first use in this function)
> > >    case BOOT_FROM_UART_ALT:
> > >         ^~~~~~~~~~~~~~~~~~
> > > arch/arm/mach-mvebu/spl.c:45:7: note: each undeclared identifier is reported only once for each function it appears in
> > > scripts/Makefile.build:280: recipe for target 'spl/arch/arm/mach-mvebu/spl.o' failed
> > 
> > Sorry about that.
> > 
> > > Could you please fix this by either adding this UART_ALT for other
> > > MVEBUs as well (AXP, I didn't check if its available), or restricting
> > > its usage on the A38x?
> > 
> > How about:
> > 
> > #ifdef BOOT_FROM_UART_ALT
> >      case BOOT_FROM_UART_ALT:
> > #endif
> >          return BOOT_DEVICE_UART;
> 
> If there is no such "alternative UART" for the other MVEBU SoCs (did
> you check this btw?), then this is most likely the best solution.

The relevant documentation appears to be table 48 in §7.5.1 of the 38x 
Hardware Specification. Unfortunately, the 0x3f value for the Boot Mode Select 
field is not documented there. I only found it in experimentation.

> Please resubmit v2 and I'll apply soon.

Will do after some more build and run-time testing.

baruch

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