The endpoint device will only read the context wp when the host rings the doorbell. And moreover the doorbell write is using writel(). This guarantess that the prior writes will be completed before ringing doorbell. So there is no need of an additional dma_wmb() to order the coherent memory writes w.r.t each other. Even if the writes gets reordered, it won't affect the endpoint device. Cc: Loic Poulain <loic.poulain@xxxxxxxxxx> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> --- drivers/bus/mhi/host/main.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c index 966ffc2458b9..6706a82d3aa8 100644 --- a/drivers/bus/mhi/host/main.c +++ b/drivers/bus/mhi/host/main.c @@ -138,11 +138,6 @@ void mhi_ring_chan_db(struct mhi_controller *mhi_cntrl, db = ring->iommu_base + (ring->wp - ring->base); - /* - * Writes to the new ring element must be visible to the hardware - * before letting h/w know there is new element to fetch. - */ - dma_wmb(); *ring->ctxt_wp = cpu_to_le64(db); mhi_chan->db_cfg.ring_db(mhi_cntrl, &mhi_chan->db_cfg, -- 2.25.1
