On Tue, Jan 11, 2022 at 6:16 PM Andre Przywara <[email protected]> wrote: > > On the Allwinner H6 SoC both the SPI0 and the eMMC device share one pin, > so cannot be used simultaneously. On Linux this is a showstopper, since > only one of them would be able to claim the pin, and the probe order is > somewhat random. The DT consequently disables SPI0 in favour of the more > useful eMMC. > > But a comment in the DT actually suggests that this could be reversed by > U-Boot, if no eMMC is actually connected. Let's now implement this: > When we fix up the device tree before booting a kernel, we iterate over > all MMC devices, and check if there is an eMMC device among them. If none > can be found, we enable SPI0 instead, to allow Linux access to the SPI > flash.
> Since this fixup is not really universally applicable to all boards, > let's hide it behind a Kconfig option, and enable it only on the one > supported board where this makes sense: the Pine H64. > > Please note that the SPI functionality is still disabled in U-Boot > proper, the pinmux clash affects us too: it would always disable the eMMC > and so spoil this algorithm here. > > Signed-off-by: Andre Przywara <[email protected]> > --- > arch/arm/mach-sunxi/Kconfig | 10 ++++++++ > board/sunxi/board.c | 50 +++++++++++++++++++++++++++++++++++++ > configs/pine_h64_defconfig | 1 + > 3 files changed, 61 insertions(+) > > diff --git a/arch/arm/mach-sunxi/Kconfig b/arch/arm/mach-sunxi/Kconfig > index 56ff1e197c..ce66453029 100644 > --- a/arch/arm/mach-sunxi/Kconfig > +++ b/arch/arm/mach-sunxi/Kconfig > @@ -1047,6 +1047,16 @@ config BLUETOOTH_DT_DEVICE_FIXUP > The used address is "bdaddr" if set, and "ethaddr" with the LSB > flipped elsewise. > > +config SUNXI_H6_ENABLE_SPIFLASH > + bool "Enable H6 SPI flash vs. eMMC enablement" > + depends on MACH_SUN50I_H6 > + default n > + help > + Enable this option if you want U-Boot check for an eMMC device > + on Allwinner H6 boards, and enable the SPI flash if none is found. > + SPI0 and MMC2 share one pin, so cannot coexist in Linux. The > + DT prefers eMMC, but if none is used, we can safely enable SPI. Why we need a separate macro, cannot we check it H6 globally as it SoC design? Jagan.
