[PATCH RFC u-boot-mvebu 4/6] arm: mvebu: Define all options for A38x BOOT_FROM_* macros

[Martin Rowe]

On Sat, 4 Mar 2023 at 11:20, Pali Rohár <pali at kernel.org> wrote:

> On Saturday 04 March 2023 11:50:34 Pali Rohár wrote:
> > Disassembling A385 BootROM binary reveal how BootROM interprets strapping
> > pins for Boot Device Mode. All possible options are:
> >
> > 0x00..0x07 -> Parallel NOR
> > 0x08..0x15 -> Parallel NAND
> > 0x16..0x17 -> Parallel NOR
> > 0x18..0x25 -> Parallel NAND
> > 0x26..0x27 -> SPI NAND
> > 0x28..0x29 -> UART xmodem
> > 0x2a..0x2b -> SATA
> > 0x2c..0x2d -> PCI Express
> > 0x2e..0x2f -> Parallel NOR
> > 0x30..0x31 -> SD / eMMC
> > 0x32..0x39 -> SPI NOR
> > 0x3a..0x3c -> Parallel NOR
> > 0x3d..0x3e -> UART debug console
> > 0x3f       -> Invalid
>
> Clearfog has 5-bit DIP switch and seems that it is directly mapped to
> the Boot Device mode with most significant bit of boot mode pulled to
> high (sixth bit not present on the switch) and flipped second, third and
> fifth bits of the boot mode.
>
> Based on documentation Clearfog DIP switch should be set to 11100 for
> SATA booting, by flipping bits it is 01010, by adding MSB it is 101010,
> which is hex 0x2a --> matches A385 SATA boot mode.
>

The Clearfog schematics indicate the switch is internally pulled to 0x36 /
110110. 110110 XOR 11100 = 101010 = 0x2a. The math checks out and
corresponds to the documented modes as well as the enumeration I did a few
years ago:
00000 nothing [0x36]
00001 nothing [0x37]
00010 SPI [0x34] (documented SPI)
00011 SPI [0x35]
00100 SPI [0x32]
00101 SPI [0x33]
00110 MMC (Card did not respond to voltage select!) [0x30]
00111 MMC [0x31] (documented SD/eMMC)
01000 nothing [0x3e]
01001 UART [0x3f] (documented UART)
01010 NOR [0x3c]
01011 nothing [0x3d]
01100 NOR [0x3a]
01101 NOR [0x3b]
01110 nothing [0x38]
01111 nothing [0x39]
10000 nothing [0x26]
10001 nothing [0x27]
10010 NAND [0x24]
10011 NAND [0x25]
10100 NAND [0x22]
10101 NAND [0x23]
10110 NAND [0x20]
10111 NAND [0x21]
11000 NOR [0x2e]
11001 nothing [0x2f]
11010 PEX0 (00) [0x2c]
11011 PEX0 (1A) [0x2d]
11100 nothing [0x2a] (I don't think I had a SATA card attached, but this is
documented SATA)
11101 nothing [0x2b]
11110 nothing [0x28]
11111 nothing [0x29]
Where "nothing" indicates no BootROM output


> Can somebody check if UART debug console boot mode works on Clearfog?
> It is boot mode when BootROM enters into simple debug console with few
> commands. Via kwboot it is possible to enter into this mode (it sends
> magic sequence) but from this information it looks like that it should
> be possible also without magic sequence, just by configuring boot mode.
>

I didn't know about this before. I tried with the magic sequence and it
works (though it needs the A38x output workaround mentioned here [1]. The
boot mode is the one set by 0x3d / 111101 or 0x3e / 111110, right?
0x3d: 111101 XOR 110110 = 01011
0x3e: 111110 XOR 110110 = 01000
Neither of those gives an interactive serial console, and even if the
output workaround is entered there is never anything that appears in the
console. It doesn't even echo the data I type in.

[1] https://manpages.debian.org/testing/u-boot-tools/kwboot.1.en.html


> > Note that Boot Device Mode Options in A38x Hardware Specifications is
> > incomplete.
> >
> > Signed-off-by: Pali Rohár <pali at kernel.org>
> > ---
> >  arch/arm/mach-mvebu/include/mach/soc.h | 11 +++++++----
> >  1 file changed, 7 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/arm/mach-mvebu/include/mach/soc.h
> b/arch/arm/mach-mvebu/include/mach/soc.h
> > index aa42db36a1ee..698b70339436 100644
> > --- a/arch/arm/mach-mvebu/include/mach/soc.h
> > +++ b/arch/arm/mach-mvebu/include/mach/soc.h
> > @@ -160,11 +160,14 @@
> >  #define BOOT_DEV_SEL_OFFS    4
> >  #define BOOT_DEV_SEL_MASK    (0x3f << BOOT_DEV_SEL_OFFS)
> >
> > -#define BOOT_FROM_NAND(x)    (x == 0x0A)
> > -#define BOOT_FROM_SATA(x)    (x == 0x2A)
> > -#define BOOT_FROM_UART(x)    (x == 0x28)
> > -#define BOOT_FROM_SPI(x)     (x == 0x32)
> > +#define BOOT_FROM_NOR(x)     ((x >= 0x00 && x <= 0x07) || x == 0x16 ||
> x == 0x17 || x == 0x2E || x == 0x2F || (x >= 0x3A && x <= 0x3C))
> > +#define BOOT_FROM_NAND(x)    ((x >= 0x08 && x <= 0x15) || (x >= 0x18 &&
> x <= 0x25))
> > +#define BOOT_FROM_SPINAND(x) (x == 0x26 || x == 0x27)
> > +#define BOOT_FROM_UART(x)    (x == 0x28 || x == 0x29)
> > +#define BOOT_FROM_SATA(x)    (x == 0x2A || x == 0x2B)
> > +#define BOOT_FROM_PEX(x)     (x == 0x2C || x == 0x2D)
> >  #define BOOT_FROM_MMC(x)     (x == 0x30 || x == 0x31)
> > +#define BOOT_FROM_SPI(x)     (x >= 0x32 && x <= 0x39)
> >
> >  #define CONFIG_SYS_TCLK              ((readl(CONFIG_SAR_REG) & BIT(15))
> ? \
> >                                200000000 : 250000000)
> > --
> > 2.20.1
> >
>