[U-Boot] ZynqMP breakage

[Simon Glass]

Hi Michal,

On 6 September 2016 at 07:40, Michal Simek <michal.simek at xilinx.com> wrote:
> Hi,
>
> On 6.9.2016 14:57, Simon Glass wrote:
>> Hi Alex,
>>
>> On 6 September 2016 at 06:55, Alexander Graf <agraf at suse.de> wrote:
>>> On 09/06/2016 02:52 PM, Simon Glass wrote:
>>>>
>>>> Hi Alex,
>>>>
>>>> On 6 September 2016 at 03:09, Alexander Graf <agraf at suse.de> wrote:
>>>>>
>>>>> On 09/06/2016 03:05 AM, Simon Glass wrote:
>>>>>>
>>>>>> Hi Alex,
>>>>>>
>>>>>> On 5 September 2016 at 04:51, Alexander Graf <agraf at suse.de> wrote:
>>>>>>>
>>>>>>> On 08/19/2016 08:45 AM, Michal Simek wrote:
>>>>>>>>
>>>>>>>> On 16.8.2016 20:39, Alexander Graf wrote:
>>>>>>>>>
>>>>>>>>> Hi Michal,
>>>>>>>>>
>>>>>>>>> I just tried to run the latest u-boot master + a few patches to
>>>>>>>>> implement
>>>>>>>>> generic PSCI RTS support on zynqmp and got this:
>>>>>>>>>
>>>>>>>>> e
>>>>>>>>> U-Boot 2016.09-rc1-00453-ga0592f1 (Aug 16 2016 - 20:27:40 +0200)
>>>>>>>>> Xilinx
>>>>>>>>> ZynqMP ZCU102
>>>>>>>>>
>>>>>>>>> I2C:   ready
>>>>>>>>> DRAM:  4 GiB
>>>>>>>>> EL Level:       EL2
>>>>>>>>> MMC:   sdhci at ff170000: 0
>>>>>>>>> Using default environment
>>>>>>>>>
>>>>>>>>> In:    serial at ff000000
>>>>>>>>> Out:   serial at ff000000
>>>>>>>>> Err:   serial at ff000000
>>>>>>>>> Bootmode: SD_MODE1
>>>>>>>>> SCSI:  SATA link 0 timeout.
>>>>>>>>> Target spinup took 0 ms.
>>>>>>>>> AHCI 0001.0301 32 slots 2 ports 6 Gbps 0x3 impl SATA mode
>>>>>>>>> flags: 64bit ncq pm clo only pmp fbss pio slum part ccc apst
>>>>>>>>> scanning bus for devices...
>>>>>>>>> "Synchronous Abort" handler, esr 0x96000004
>>>>>>>>> ELR:     7ff42d20
>>>>>>>>> LR:      7ff3ff10
>>>>>>>>> x0 : 0000000000000000 x1 : 0000000000000000
>>>>>>>>> x2 : 0000000000000001 x3 : 000000007df1aa80
>>>>>>>>> x4 : aaaaaaaaaaaaaaaa x5 : 0000000000000001
>>>>>>>>> x6 : 0000000000000200 x7 : 0000000000000004
>>>>>>>>> x8 : 000000007ff9f800 x9 : 0000000000000008
>>>>>>>>> x10: 000000007ff9f8f0 x11: 0000000000000000
>>>>>>>>> x12: 00000000ffffffff x13: 00000000ffffffff
>>>>>>>>> x14: 000000007ff8242f x15: 000000007ff82435
>>>>>>>>> x16: 000000007ff84388 x17: 000000007ff84388
>>>>>>>>> x18: 000000007df1ade8 x19: 000000007df1aa80
>>>>>>>>> x20: 000000007ff92cb8 x21: 000000007ff9f800
>>>>>>>>> x22: 000000007ff9f000 x23: 0000000000000078
>>>>>>>>> x24: 000000007ff9f8f0 x25: 0000000000000000
>>>>>>>>> x26: 000000007ff9f800 x27: 000000007ff9f000
>>>>>>>>> x28: 000000007ff9fb00 x29: 000000007df1aca0
>>>>>>>>>
>>>>>>>>> Resetting CPU ...
>>>>>>>>>
>>>>>>>>> resetting …
>>>>>>>>>
>>>>>>>>> Is this a known problem?
>>>>>>>>
>>>>>>>> Is this issue with usb?
>>>>>>>> I have usb off on zcu102 that's why if this usb issue
>>>>>>>> I am not aware about it.
>>>>>>>
>>>>>>>
>>>>>>> After a bit of digging, turns out it's CONFIG_BLK. If I disable that
>>>>>>> things
>>>>>>> work again (albeit without mmc access, since that one requires
>>>>>>> CONFIG_BLK
>>>>>>> now).
>>>>>>
>>>>>> I don't have a zynqmp device, so cannot test with that unfortunately.
>>>>>
>>>>>
>>>>> Well, QEMU supports zcu102 emulation in the latest version, so you could
>>>>> use
>>>>> that to emulate the board:
>>>>>
>>>>>    $ qemu-system-aarch64 -M xlnx-zcu102 -kernel u-boot.elf -nographic -m
>>>>> 2G
>>>>> -drive file=u-boot,id=d,if=none -device ide-drive,drive=d,bus=ide.0
>>>>>
>>>>> However, I don't see the data abort with the emulated device, only with
>>>>> actual hardware. Probably because real hardware is more upset about
>>>>> reading
>>>>> from address 0 ;). But I can provoke the oops even in QEMU if I unmap the
>>>>> first page from the memory map using the patch below.
>>>>>
>>>>> The oops happens in blk_dread because block_dev->bdev is NULL.
>>>>
>>>> Yes, this field really should be removed. As the comment says it's a
>>>> hangover from pre-CONFIG_BLK where functions use a struct blk_dev * to
>>>> specify the block device instead of a struct udevice *. It came up
>>>> recently on a patch you sent also which is why I am so against using
>>>> it.
>>>>
>>>> That said, I'm not sure why it is unset. The path should be:
>>>>
>>>> sdhci_bind()
>>>> mmc_bind()
>>>> blk_create_devicef()
>>>> blk_create_device()
>>>> which sets:
>>>>
>>>> desc->bdev = dev;
>>>>
>>>> [snip]
>>>
>>>
>>> The special case about ZynqMP is that it has 2 storage backends, one that
>>> uses DM (the sdhc controller) and one that isn't converted to DM (the AHCI
>>> controller). I guess something goes wrong with the latter.
>>
>> OK, well it would be good to convert it. It certainly won't work
>> without it and I'm a little surprised that it compiles :-)
>
> probably good time to convert it. Driver itself has only sata init
> sequence and then it is just compatible with ahci. That's why conversion
> should be pretty easy.
>
> Simon: Which driver should I use as inspiration for conversion?

I looked at sata a while back, so here are a few ideas...

Existing sata.h functions should be #ifdef'd out

- init_sata() should be handled by the driver probe() method
- hopefully sata_stop() can be handled by driver remove() method
- the block device can handle read and write
- we probably need sata methods for scan and reset

There is also ahci.h.

There is a sata_sandbox.c driver which you could convert to DM,
perhaps with a new DM_SATA option (like DM_MMC).

Regards,
Simon