[U-Boot] [PATCH v7 2/3] mmc: meson: add MMC driver for Meson GX (S905)

[Heinrich Schuchardt]

On 04/15/2017 11:51 PM, Andreas Färber wrote:
> Am 15.04.2017 um 23:16 schrieb Andreas Färber:
>> Am 15.04.2017 um 23:04 schrieb Alexander Graf:
>>>> Am 15.04.2017 um 22:34 schrieb Andreas Färber <afaerber at suse.de>:
>>>>> Am 15.04.2017 um 20:27 schrieb Alexander Graf:
>>>>>> On 15.04.17 20:18, Heiner Kallweit wrote:
>>>>>>> Am 15.04.2017 um 17:05 schrieb Andreas Färber:
>>>>>>> But for the Vega S95 Telos I needed to disable the first of three MMC
>>>>>>> nodes (SDIO) - otherwise U-Boot would happily iterate over them for
>>>>>>> distro boot with Heinrich's patch, but GRUB would come up with no disks,
>>>>>>> so that booting failed. I'm not yet sure why, maybe it's a UEFI-side
>>>>>>> problem in that it is the first MMC device that is absent rather than
>>>>>>> the last one?
>>>>>>>
>>>>>> I don't own this device so I can just provide a guess.
>>>>>> Based on DT the device ordering most likely is:
>>>>>> mmc0: SDIO
>>>>>> mmc1: SD
>>>>>> mmc2: eMMC
>>>> [...]
>>>>> If grub comes up, distro boot has successfully found the target binary
>>>>> and executed it. For some reason, grub can not find its boot origin though.
>>>>>
>>>>> Andreas, please add debug prints like the ones below and check that the
>>>>> device names match:
>>>>
>>>> U-Boot 2017.05-rc1-00318-g082535f-dirty (Apr 15 2017 - 22:29:17 +0200)
>>>> vega-s95
>>>>
>>>> DRAM:  2 GiB
>>>> MMC:   mmc at 70000: 0, mmc at 72000: 1, mmc at 74000: 2
>>>> Using default environment
>>>>
>>>> In:    serial at 4c0
>>>> Out:   serial at 4c0
>>>> Err:   serial at 4c0
>>>> Net:   eth0: ethernet at c9410000
>>>> Hit any key to stop autoboot:  0
>>>> mmc_init: -95, time 1806
>>>> MMC Device 0 not found
>>>> no mmc device at slot 0
>>>> switch to partitions #0, OK
>>>> mmc1 is current device
>>>> Scanning mmc 1:1...
>>>> Setting boot device name to '//boot/dtb/amlogic/meson-gxbb-v'
>>>> 20335 bytes read in 43 ms (460.9 KiB/s)
>>>> Found EFI removable media binary efi/boot/bootaa64.efi
>>>> Setting boot device name to '/efi/boot/bootaa64.efi'
>>>> reading efi/boot/bootaa64.efi
>>>> 129024 bytes read in 13 ms (9.5 MiB/s)
>>>> ## Starting EFI application at 01080000 ...
>>>> mmc_init: -95, time 1807
>>>> Found 0 disks
>>>
>>> That looks like efi_disk didn't manage to enumerate any devices?
>>
>> Apparently. The last line comes from
>> lib/efi_loader_efi_disk:efi_disk_register(), and CONFIG_BLK=y. As you
>> can see, there is not a single "Scanning disk" line, so I guess we do
>> not iterate over uclass devices properly?
>>
>> On the Odroid-C2 I get this:
>>
>> Scanning disk mmc at 72000.blk...
>> Card did not respond to voltage select!
>> mmc_init: -95, time 9
>> Found 1 disks
>>
>> Therefore my guess that it matters at what point in time - before or
>> after the disk we want - the error accessing an MMC device happens.
> 
> For comparison, Vega S95 with first MMC node disabled in DT:
> 
> Scanning disk mmc at 72000.blk...
> Adding disk device 'mmc at 72000.blk'
> ** First descriptor is NOT a primary desc on 1:1 **
> Scanning disk mmc at 74000.blk...
> Adding disk device 'mmc at 74000.blk'
> Found 2 disks
> 
> Regards,
> Andreas
> 
By adding sd_mmc_a to the odroid-c2.dts I was able to reproduce the
problem on the Odroid C2.

While booting from SD card via booti still worked
bootefi would not find any block device:

=> bootefi hello
## Starting EFI application at 01000000 ...
WARNING: Invalid device tree, expect boot to fail
efi_add_memory_map: 0x7cf53000 0x1 2 yes
uclass_find_device_by_seq: 0 -1
uclass_find_device_by_seq: 0 0
   - -1 -1
   - -1 -1
   - -1 -1
   - not found
set_state_simple op missing
blk_get_device: if_type=6, devnum=0: mmc at 70000.blk, 6, 0
mmc_init: -95, time 1807
Found 0 disks
efi_add_memory_map: 0x7cf52000 0x1 6 yes
do_bootefi_exec:234 Jumping to 0x7cf53148
EFI: Entry efi_cout_output_string(000000007ff94b38, 000000007cf53280)
Hello, world!
EFI: Entry efi_exit(000000007ffa4598, 0, 0, 0000000000000000)
## Application terminated, r = 0

In the debug output you can see that after trying non-existant
mmc at 70000.blk no further devices are scanned. mmc at 72000.blk which has
the SD card is not enumerated.

Best regards

Heinrich Schuchardt