[PATCH] arm: rpi: explicitly enumerate mmc boot targets

[Ben Wolsieffer]

Hi Peter,

On Sun, Oct 08, 2023 at 07:21:57PM +0100, Peter Robinson wrote:
> On Sat, Oct 7, 2023 at 4:55 PM Ben Wolsieffer <benwolsieffer at gmail.com> wrote:
> >
> > Using the unqualified "mmc" boot target causes the Raspberry Pi 4 to
> > fail to boot. c771e5b explains this approach as follows:
> >
> > > We don't need to specify the mmc devices individually, since they are
> > > used in order from 0 to 2, and standard boot uses that order anyway.
> >
> > In practice, U-Boot first attempts to boot from the unconnected mmc1
> > interface, and, when this fails, moves on to attempt the USB and network
> > boot targets rather than trying mmc0.
> 
> Really? It shouldn't be enumerating it if it's not defined in device
> tree, I've not seen this in my testing.

It does seem odd, but U-Boot definitely sees two MMC interfaces:

U-Boot> mmc list
mmcnr at 7e300000: 1
mmc at 7e340000: 0 (SD)

> 
> > This patch explicitly enumerates the mmc interfaces, causing each to be
> > attempted in turn. This matches what is done on other boards, and allows
> > the system to boot successfully.
> >
> > Fixes: c771e5b8c2 ("arm: rpi: Switch to standard boot")
> > Signed-off-by: Ben Wolsieffer <benwolsieffer at gmail.com>
> > ---
> >  board/raspberrypi/rpi/rpi.env | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/board/raspberrypi/rpi/rpi.env b/board/raspberrypi/rpi/rpi.env
> > index 30228285ed..02210b97b5 100644
> > --- a/board/raspberrypi/rpi/rpi.env
> > +++ b/board/raspberrypi/rpi/rpi.env
> > @@ -74,4 +74,4 @@ pxefile_addr_r=0x02500000
> >  fdt_addr_r=0x02600000
> >  ramdisk_addr_r=0x02700000
> >
> > -boot_targets=mmc usb pxe dhcp
> > +boot_targets=mmc0 mmc1 mmc2 usb pxe dhcp
> 
> Why are you adding mmc1 and mmc2 if they're not connected?

I was trying to match the old distro boot behavior, which had three MMC
interfaces listed.