svn commit: r285270 - head/sys/sys

[Zbigniew Bodek]

Because machdep header includes this file (not the other way).

Best regards
zbb

2015-07-08 16:30 GMT+02:00 Adrian Chadd <adrian.chadd at gmail.com>:
> Why is this implemented in sys/sys/bus_dma.h, rather than in a machdep header?
>
>
> -a
>
>
> On 8 July 2015 at 06:53, Zbigniew Bodek <zbb at freebsd.org> wrote:
>> Author: zbb
>> Date: Wed Jul  8 13:52:59 2015
>> New Revision: 285270
>> URL: https://svnweb.freebsd.org/changeset/base/285270
>>
>> Log:
>>   Add memory barrier to bus_dmamap_sync()
>>
>>   On platforms which are fully IO-coherent, the map might be null.
>>   We need to guarantee that all data is observable after the
>>   sync operation is called. Add a memory barrier to ensure that on ARM.
>>
>>   Reviewed by:   andrew, kib
>>   Obtained from: Semihalf
>>   Sponsored by:  The FreeBSD Foundation
>>   Differential Revision: https://reviews.freebsd.org/D3012
>>
>> Modified:
>>   head/sys/sys/bus_dma.h
>>
>> Modified: head/sys/sys/bus_dma.h
>> ==============================================================================
>> --- head/sys/sys/bus_dma.h      Wed Jul  8 13:19:13 2015       (r285269)
>> +++ head/sys/sys/bus_dma.h      Wed Jul  8 13:52:59 2015        (r285270)
>> @@ -282,13 +282,25 @@ int bus_dmamem_alloc(bus_dma_tag_t dmat,
>>  void bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map);
>>
>>  /*
>> - * Perform a synchronization operation on the given map.
>> + * Perform a synchronization operation on the given map. If the map
>> + * is NULL we have a fully IO-coherent system. On every ARM architecture
>> + * there must be a memory barrier placed to ensure that all data
>> + * accesses are visible before going any further.
>>   */
>>  void _bus_dmamap_sync(bus_dma_tag_t, bus_dmamap_t, bus_dmasync_op_t);
>> +#if defined(__arm__)
>> +       #define __BUS_DMAMAP_SYNC_DEFAULT               mb();
>> +#elif defined(__aarch64__)
>> +       #define __BUS_DMAMAP_SYNC_DEFAULT               dmb(sy);
>> +#else
>> +       #define __BUS_DMAMAP_SYNC_DEFAULT               {}
>> +#endif
>>  #define bus_dmamap_sync(dmat, dmamap, op)                      \
>>         do {                                                    \
>>                 if ((dmamap) != NULL)                           \
>>                         _bus_dmamap_sync(dmat, dmamap, op);     \
>> +               else                                            \
>> +                       __BUS_DMAMAP_SYNC_DEFAULT               \
>>         } while (0)
>>
>>  /*
>>
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