diff options
| author | Neil Turton <nturton@solarflare.com> | 2011-04-11 11:42:43 +0100 |
|---|---|---|
| committer | Ben Hutchings <bhutchings@solarflare.com> | 2011-04-12 23:52:44 +0100 |
| commit | fcfa060468a4edcf776f0c1211d826d5de1668c1 (patch) | |
| tree | 3e8387932c5cc10facffa248ecfb648564a9ae5e /drivers/net/sfc/io.h | |
| parent | d4fabcc8e8ecac21262b1a5b9684fe415b128bd2 (diff) | |
sfc: Use rmb() to ensure reads occur in order
Enabling write-combining may also enable read reordering. The BIU is
only guaranteed to read from a 128-bit CSR or 64-bit SRAM word when
the host reads from its lowest address; otherwise the BIU may use the
latched value. Therefore we need to reinstate the read memory
barriers after the first read operation for each CSR or SRAM word.
Signed-off-by; Ben Hutchings <bhutchings@solarflare.com>
Diffstat (limited to 'drivers/net/sfc/io.h')
| -rw-r--r-- | drivers/net/sfc/io.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/net/sfc/io.h b/drivers/net/sfc/io.h index d9d8c2ef107..cc978803d48 100644 --- a/drivers/net/sfc/io.h +++ b/drivers/net/sfc/io.h @@ -152,6 +152,7 @@ static inline void efx_reado(struct efx_nic *efx, efx_oword_t *value, spin_lock_irqsave(&efx->biu_lock, flags); value->u32[0] = _efx_readd(efx, reg + 0); + rmb(); value->u32[1] = _efx_readd(efx, reg + 4); value->u32[2] = _efx_readd(efx, reg + 8); value->u32[3] = _efx_readd(efx, reg + 12); @@ -174,6 +175,7 @@ static inline void efx_sram_readq(struct efx_nic *efx, void __iomem *membase, value->u64[0] = (__force __le64)__raw_readq(membase + addr); #else value->u32[0] = (__force __le32)__raw_readl(membase + addr); + rmb(); value->u32[1] = (__force __le32)__raw_readl(membase + addr + 4); #endif spin_unlock_irqrestore(&efx->biu_lock, flags); |