Re: [dpdk-dev] [PATCH] fm10k: fix the compilation on big endian platforms

[Chao Zhu <chaozhu@linux.vnet.ibm.com>]

On 2015/8/3 17:06, Thomas Monjalon wrote:
> 2015-08-03 14:31, Chao Zhu:
>> The rte_cpu_to_le_32 function can't be used to define const variables
>> because it has different implementation on big endian platforms. If
>> doing so, it will cause 'initializer element is not constant' compiling
>> error. This patch fixes this problem.
>> --- a/drivers/net/fm10k/base/fm10k_tlv.c
>> +++ b/drivers/net/fm10k/base/fm10k_tlv.c
> You cannot change a base driver file except the osdep header where
> FM10K_CPU_TO_LE32 is defined.
>
> I don't understand why it doesn't give you a constant, given this definition:
>
> #define rte_bswap32(x) ((uint32_t)(__builtin_constant_p(x) ?        \
>                     rte_constant_bswap32(x) :        \
>                     rte_arch_bswap32(x)))
>
> Have you tried CONFIG_RTE_FORCE_INTRINSICS=y ?
> It should trigger this definition:
>
> #define rte_bswap32(x) __builtin_bswap32(x)
Yes.  CONFIG_RTE_FORCE_INTRINSICS=y works on Power Big endian.  But if I 
turn off this, the error happens.  Seems rte_constant_bswap32 doesn't 
work on Power8? I'll try to check it.
>
>> -STATIC const __le32 test_le[2] = { FM10K_CPU_TO_LE32(0x12345678),
>> -				   FM10K_CPU_TO_LE32(0x9abcdef0)};
>> +#if RTE_BYTE_ORDER == RTE_BIG_ENDIAN
>> +STATIC const __le32 test_le[2] = {0x78563412,0xf0debc9a};
>> +#else
>> +STATIC const __le32 test_le[2] = {0x12345678,0x9abcdef0};
>> +#endif