| Message ID | 1521988761-30344-7-git-send-email-okaya@codeaurora.org (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Sun, Mar 25, 2018 at 7:39 AM, Sinan Kaya <okaya@codeaurora.org> wrote: > Code includes wmb() followed by writel(). writel() already has a barrier on > some architectures like arm64. > > This ends up CPU observing two barriers back to back before executing the > register write. > > Create a new wrapper function with relaxed write operator. Use the new > wrapper when a write is following a wmb(). > > Since code already has an explicit barrier call, changing writel() to > writel_relaxed(). > > Also add mmiowb() so that write code doesn't move outside of scope. This line in the patch description is not needed anymore. Other than that, Acked-by: Michael Chan <michael.chan@broadcom.com> Thanks. > > Signed-off-by: Sinan Kaya <okaya@codeaurora.org> -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c index 1500243..befb538 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c @@ -1922,7 +1922,7 @@ static int bnxt_poll_work(struct bnxt *bp, struct bnxt_napi *bnapi, int budget) /* Sync BD data before updating doorbell */ wmb(); - bnxt_db_write(bp, db, DB_KEY_TX | prod); + bnxt_db_write_relaxed(bp, db, DB_KEY_TX | prod); } cpr->cp_raw_cons = raw_cons; diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h index 1989c47..5e453b9 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h @@ -1401,6 +1401,15 @@ static inline u32 bnxt_tx_avail(struct bnxt *bp, struct bnxt_tx_ring_info *txr) ((txr->tx_prod - txr->tx_cons) & bp->tx_ring_mask); } +/* For TX and RX ring doorbells with no ordering guarantee*/ +static inline void bnxt_db_write_relaxed(struct bnxt *bp, void __iomem *db, + u32 val) +{ + writel_relaxed(val, db); + if (bp->flags & BNXT_FLAG_DOUBLE_DB) + writel_relaxed(val, db); +} + /* For TX and RX ring doorbells */ static inline void bnxt_db_write(struct bnxt *bp, void __iomem *db, u32 val) {
Code includes wmb() followed by writel(). writel() already has a barrier on some architectures like arm64. This ends up CPU observing two barriers back to back before executing the register write. Create a new wrapper function with relaxed write operator. Use the new wrapper when a write is following a wmb(). Since code already has an explicit barrier call, changing writel() to writel_relaxed(). Also add mmiowb() so that write code doesn't move outside of scope. Signed-off-by: Sinan Kaya <okaya@codeaurora.org> --- drivers/net/ethernet/broadcom/bnxt/bnxt.c | 2 +- drivers/net/ethernet/broadcom/bnxt/bnxt.h | 9 +++++++++ 2 files changed, 10 insertions(+), 1 deletion(-)