[U-Boot] U-Boot, dm, ubi: struct device is declared twice

[Simon Glass]

Hi Heiko,

On 4 May 2014 23:55, Heiko Schocher <hs at denx.de> wrote:
> Hello Simon,
>
> Am 02.05.2014 16:29, schrieb Simon Glass:
>
>> Hi,
>>
>> On 2 May 2014 01:16, Heiko Schocher<hs at denx.de>  wrote:
>>>
>>> Hello Marek,
>>>
>>> Am 02.05.2014 08:06, schrieb Marek Vasut:
>>>
>>>> On Friday, May 02, 2014 at 07:19:01 AM, Heiko Schocher wrote:
>>>>>
>>>>>
>>>>> Hello Simon, Marek,
>>>>>
>>>>> just updating to current mainline code and defining
>>>>> CONFIG_SYS_GENERIC_BOARD pops up the following error:
>>>>>
>>>>>     CC      common/board_r.o
>>>>> In file included from include/linux/mtd/flashchip.h:21:0,
>>>>>                     from include/linux/mtd/nand.h:31,
>>>>>                     from include/nand.h:39,
>>>>>                     from common/board_r.c:40:
>>>>> include/ubi_uboot.h:202:8: error: redefinition of 'struct device'
>>>>>     struct device {
>>>>>            ^
>>>>> In file included from include/dm.h:10:0,
>>>>>                     from common/board_r.c:21:
>>>>> include/dm/device.h:56:8: note: originally defined here
>>>>>     struct device {
>>>>>            ^
>>>>> make[1]: *** [common/board_r.o] Fehler 1
>>>>> make: *** [common] Fehler 2
>>>>> pollux:u-boot hs [20140502] $
>>>>>
>>>>> for a not yet mainlined imx6 board using UBI/UBIFS on nand. I am
>>>>> currently sync current Linux MTD/UBI and UBIFS code to U-Boot, but
>>>>> I think this error should pop up for all boards using DM and UBI ...
>>>>
>>>>
>>>>
>>>> In the ideal case, we should use the same struct device for both UBI and
>>>> DM, but
>>>
>>>
>>>
>>> Yes, that was also my first thought ...
>>>
>>>
>>>> we cannot do that. Thus, renaming the DM struct device would be the best
>>>> option
>>>> for now.
>>>
>>>
>>>
>>> Ok. I prepare a patch for this.
>>
>>
>> Linux also has struct device, so I wondered how it avoids this problem
>> and took a look.
>
>
> Yes, the MTD/UBI and UBIFS subsystem is Code from Linux and it uses
> the linux "struct device". I wonder, how DM and UBI compile together.
>
> Is this tried somewhere?

Not yet, but it sounds like we are hitting the problem now.

>
> (As I see drivers/usb/musb-new uses also "struct device" ...)
>
>
>> This header file seems like a special thing for U-Boot - I wonder if
>
>
> Yes, it includes some missing defines, structs for the UBI Subsystem,
> so we could use Linux Code ... but we have also "include/linux/compat.h
> for this ... Maybe it is worth to delete this include/ubi_uboot.h
> and move the missing symbols to include/linux/compat.h?
>
>
>> it would be better to use #define at the top of the C file for the
>
>
> Yes, I thought about this too ...
>
> The UBI subsystem in U-Boot has defined "UBI_LINUX" instead of
> "__UBOOT__" ... which surprised me too.
>
>  maybe I prepare such a change (delete "UBI_LINUX" and use
> "__UBOOT__") for the new sync with current Linux MTD/UBI and UBIFS
> layer?
>
>
>> compatibility stuff (#define device ubi_device) rather than modify dm?
>
>
> Hmm... I can try this ... but I am not really happy to have
> such a define.

Me neither, but the justification is that we are trying to make
incompatible code work with minimal changes.

>
>
>> It does seem very strange to me, particularly as from what I can tell,
>> struct device is just a cut down version of the Linux struct.
>
>
> Wouldn;t it be better to move this to include/linux/device.h then?
>
> Looking in U-Boot:include/dm/device.h "struct device":
>
> struct device {
> *        struct driver *driver;
> *        const char *name;
> *        void *platdata;
> *        int of_offset;
>         struct device *parent;
> *        void *priv;
> *        struct uclass *uclass;
> *        void *uclass_priv;
> *        struct list_head uclass_node;
> *        struct list_head child_head;
> *        struct list_head sibling_node;
> *        uint32_t flags;
> };
>
> All "*" are different to current mainline linux or not in it ...
> so I prefer first to rename the DM "struct device" into for example
> "struct u_device" ... Maybe we can sync them once with the linux
> "struct device"

OK, I prefer not to do this, since we are renaming U-Boot files to
make Linux source work in the U-Boot tree. But this is not my decision
and it may be a more widespread problem in the future. So if you think
this is better, how about udevice? You will then need to rename all
the APIs.

Regards,
Simon