diff options
Diffstat (limited to 'drivers/net/ethernet/sfc/io.h')
| -rw-r--r-- | drivers/net/ethernet/sfc/io.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/net/ethernet/sfc/io.h b/drivers/net/ethernet/sfc/io.h index 96ce507d860..afb94aa2c15 100644 --- a/drivers/net/ethernet/sfc/io.h +++ b/drivers/net/ethernet/sfc/io.h @@ -66,6 +66,18 @@ #define EFX_USE_QWORD_IO 1 #endif +/* Hardware issue requires that only 64-bit naturally aligned writes + * are seen by hardware. Its not strictly necessary to restrict to + * x86_64 arch, but done for safety since unusual write combining behaviour + * can break PIO. + */ +#ifdef CONFIG_X86_64 +/* PIO is a win only if write-combining is possible */ +#ifdef ARCH_HAS_IOREMAP_WC +#define EFX_USE_PIO 1 +#endif +#endif + #ifdef EFX_USE_QWORD_IO static inline void _efx_writeq(struct efx_nic *efx, __le64 value, unsigned int reg) |