[U-Boot] [PATCH] global_data: Move x86 specific GD flags into common flags

[Stefan Roese]

Hi Simon,

On 15.08.19 09:35, Simon Goldschmidt wrote:
> Hi Stefan,
> 
> On Thu, Aug 15, 2019 at 9:05 AM Stefan Roese <sr at denx.de> wrote:
>>
>> Currently the upper 16 bits of the GD flags are reserved for
>> architecture specific flags. But only x86 uses 2 bits of these 16 bits
>> and sprinkling those flags in multiple headers is confusing and does not
>> scale.
>>
>> This patch now moves the x86 flags into the common header and removes
>> the comment about the reservation of the upper 16 bits.
>>
>> Signed-off-by: Stefan Roese <sr at denx.de>
>> Cc: Bin Meng <bmeng.cn at gmail.com>
>> Cc: Simon Glass <sjg at chromium.org>
>> Cc: Tom Rini <trini at konsulko.com>
>> Cc: Simon Goldschmidt <simon.k.r.goldschmidt at gmail.com>
>> ---
>>   arch/x86/include/asm/global_data.h | 6 ------
>>   include/asm-generic/global_data.h  | 6 +++++-
>>   2 files changed, 5 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/global_data.h b/arch/x86/include/asm/global_data.h
>> index 797397e697..17a4d34491 100644
>> --- a/arch/x86/include/asm/global_data.h
>> +++ b/arch/x86/include/asm/global_data.h
>> @@ -137,10 +137,4 @@ static inline __attribute__((no_instrument_function)) gd_t *get_fs_gd_ptr(void)
>>
>>   #endif
>>
>> -/*
>> - * Our private Global Data Flags
>> - */
>> -#define GD_FLG_COLD_BOOT       0x10000 /* Cold Boot */
>> -#define GD_FLG_WARM_BOOT       0x20000 /* Warm Boot */
>> -
>>   #endif /* __ASM_GBL_DATA_H */
>> diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
>> index 5372d5d8cd..42ae61c781 100644
>> --- a/include/asm-generic/global_data.h
>> +++ b/include/asm-generic/global_data.h
>> @@ -150,7 +150,7 @@ typedef struct global_data {
>>   #endif
>>
>>   /*
>> - * Global Data Flags - the top 16 bits are reserved for arch-specific flags
>> + * Common Global Data Flags
>>    */
>>   #define GD_FLG_RELOC           0x00001 /* Code was relocated to RAM       */
>>   #define GD_FLG_DEVINIT         0x00002 /* Devices have been initialized   */
>> @@ -170,4 +170,8 @@ typedef struct global_data {
>>   #define GD_FLG_LOG_READY       0x08000 /* Log system is ready for use     */
>>   #define GD_FLG_WDT_READY       0x10000 /* Watchdog is ready for use       */
>>
>> +/* x86 specific GD flags */
>> +#define GD_FLG_COLD_BOOT       0x20000 /* Cold Boot */
>> +#define GD_FLG_WARM_BOOT       0x40000 /* Warm Boot */
> 
> I think this change is generally good, but I failed to find code using the flag
> GD_FLG_WARM_BOOT (it's only set, not checked). Only the cold-boot flag is used
> (in coreboot's last_stage_init).
> 
> So, since we don't have too many bits free here, instead of wasting 2 for x86,
> could we probably remove one of these. Especially since you can either have
> warm OR cold, but not both (so the absence of 'WARM' could mean 'COLD')?

Yes. I already commented on those 2 x86 bits and their (non-)usage:

https://lists.denx.de/pipermail/u-boot/2019-August/380634.html
&
https://lists.denx.de/pipermail/u-boot/2019-August/380800.html

My suggestion is to apply this patch now and re-work the x86 flags usage
in a later patch (most likely remove one of those bits). The main reason
being that this double usage of 0x10000 needs to get fixed quickly.

Thanks,
Stefan