From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754220AbdCNAmf (ORCPT ); Mon, 13 Mar 2017 20:42:35 -0400 Received: from mail-qt0-f196.google.com ([209.85.216.196]:33106 "EHLO mail-qt0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754118AbdCNAm3 (ORCPT ); Mon, 13 Mar 2017 20:42:29 -0400 From: Doug Berger To: f.fainelli@gmail.com Cc: robh+dt@kernel.org, mark.rutland@arm.com, davem@davemloft.net, rafal@milecki.pl, xow@google.com, joel@jms.id.au, jon.mason@broadcom.com, netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, pgynther@google.com, jaedon.shin@gmail.com, Doug Berger Subject: [PATCH net-next 07/12] net: bcmgenet: clear status to reduce spurious interrupts Date: Mon, 13 Mar 2017 17:41:37 -0700 Message-Id: <20170314004142.4746-8-opendmb@gmail.com> X-Mailer: git-send-email 2.11.1 In-Reply-To: <20170314004142.4746-1-opendmb@gmail.com> References: <20170314004142.4746-1-opendmb@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since the DMA interrupt status is latched and the DMA servicing can be polled, it is a good idea to clear the latched status of a DMA interrupt before performing the service that would be invoked by the interrupt. This prevents old status from causing spurious interrupts when the interrupt is unmasked at a later time. Signed-off-by: Doug Berger --- drivers/net/ethernet/broadcom/genet/bcmgenet.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c index 661ca1b39c89..1f94ba1773dd 100644 --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c @@ -1174,6 +1174,14 @@ static unsigned int __bcmgenet_tx_reclaim(struct net_device *dev, unsigned int txbds_ready; unsigned int txbds_processed = 0; + /* Clear status before servicing to reduce spurious interrupts */ + if (ring->index == DESC_INDEX) + bcmgenet_intrl2_0_writel(priv, UMAC_IRQ_TXDMA_DONE, + INTRL2_CPU_CLEAR); + else + bcmgenet_intrl2_1_writel(priv, (1 << ring->index), + INTRL2_CPU_CLEAR); + /* Compute how many buffers are transmitted since last xmit call */ c_index = bcmgenet_tdma_ring_readl(priv, ring->index, TDMA_CONS_INDEX) & DMA_C_INDEX_MASK; @@ -1584,10 +1592,21 @@ static unsigned int bcmgenet_desc_rx(struct bcmgenet_rx_ring *ring, unsigned long dma_flag; int len; unsigned int rxpktprocessed = 0, rxpkttoprocess; - unsigned int p_index; + unsigned int p_index, mask; unsigned int discards; unsigned int chksum_ok = 0; + /* Clear status before servicing to reduce spurious interrupts */ + if (ring->index == DESC_INDEX) { + bcmgenet_intrl2_0_writel(priv, UMAC_IRQ_RXDMA_DONE, + INTRL2_CPU_CLEAR); + } else { + mask = 1 << (UMAC_IRQ1_RX_INTR_SHIFT + ring->index); + bcmgenet_intrl2_1_writel(priv, + mask, + INTRL2_CPU_CLEAR); + } + p_index = bcmgenet_rdma_ring_readl(priv, ring->index, RDMA_PROD_INDEX); discards = (p_index >> DMA_P_INDEX_DISCARD_CNT_SHIFT) & -- 2.11.1