From patchwork Fri Jan 2 22:15:59 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Felipe Balbi X-Patchwork-Id: 425066 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 86F3314007D for ; Sat, 3 Jan 2015 09:16:42 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752366AbbABWQd (ORCPT ); Fri, 2 Jan 2015 17:16:33 -0500 Received: from bear.ext.ti.com ([192.94.94.41]:46448 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752190AbbABWQb (ORCPT ); Fri, 2 Jan 2015 17:16:31 -0500 Received: from dflxv15.itg.ti.com ([128.247.5.124]) by bear.ext.ti.com (8.13.7/8.13.7) with ESMTP id t02MGT7H023771; Fri, 2 Jan 2015 16:16:29 -0600 Received: from DLEE71.ent.ti.com (dlee71.ent.ti.com [157.170.170.114]) by dflxv15.itg.ti.com (8.14.3/8.13.8) with ESMTP id t02MGTat009694; Fri, 2 Jan 2015 16:16:29 -0600 Received: from dflp32.itg.ti.com (10.64.6.15) by DLEE71.ent.ti.com (157.170.170.114) with Microsoft SMTP Server id 14.3.174.1; Fri, 2 Jan 2015 16:16:28 -0600 Received: from localhost (ileax41-snat.itg.ti.com [10.172.224.153]) by dflp32.itg.ti.com (8.14.3/8.13.8) with ESMTP id t02MGSMa026768; Fri, 2 Jan 2015 16:16:28 -0600 From: Felipe Balbi To: David Miller CC: Mugunthan V N , Yegor Yefremov , Linux OMAP Mailing List , , Felipe Balbi , Subject: [PATCH] net: ethernet: cpsw: fix hangs with interrupts Date: Fri, 2 Jan 2015 16:15:59 -0600 Message-ID: <1420236959-32444-1-git-send-email-balbi@ti.com> X-Mailer: git-send-email 2.2.0 MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The CPSW IP implements pulse-signaled interrupts. Due to that we must write a correct, pre-defined value to the CPDMA_MACEOIVECTOR register so the controller generates a pulse on the correct IRQ line to signal the End Of Interrupt. The way the driver is written today, all four IRQ lines are requested using the same IRQ handler and, because of that, we could fall into situations where a TX IRQ fires but we tell the controller that we ended an RX IRQ (or vice-versa). This situation triggers an IRQ storm on the reserved IRQ 127 of INTC which will in turn call ack_bad_irq() which will, then, print a ton of: unexpected IRQ trap at vector 00 In order to fix the problem, we are moving all calls to cpdma_ctlr_eoi() inside the IRQ handler and making sure we *always* write the correct value to the CPDMA_MACEOIVECTOR register. Note that the algorithm assumes that IRQ numbers and value-to-be-written-to-EOI are proportional, meaning that a write of value 0 would trigger an EOI pulse for the RX_THRESHOLD Interrupt and that's the IRQ number sitting in the 0-th index of our irqs_table array. This, however, is safe at least for current implementations of CPSW so we will refrain from making the check smarter (and, as a side-effect, slower) until we actually have a platform where IRQ lines are swapped. This patch has been tested for several days with AM335x- and AM437x-based platforms. AM57x was left out because there are still pending patches to enable ethernet in mainline for that platform. A read of the TRM confirms the statement on previous paragraph. Reported-by: Yegor Yefremov Fixes: 510a1e7 (drivers: net: davinci_cpdma: acknowledge interrupt properly) Cc: # v3.9+ Signed-off-by: Felipe Balbi Acked-by: Tony Lindgren --- should be applied on 'net' for current -rc drivers/net/ethernet/ti/cpsw.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c index c560f9a..e61ee83 100644 --- a/drivers/net/ethernet/ti/cpsw.c +++ b/drivers/net/ethernet/ti/cpsw.c @@ -757,6 +757,14 @@ requeue: static irqreturn_t cpsw_interrupt(int irq, void *dev_id) { struct cpsw_priv *priv = dev_id; + int value = irq - priv->irqs_table[0]; + + /* NOTICE: Ending IRQ here. The trick with the 'value' variable above + * is to make sure we will always write the correct value to the EOI + * register. Namely 0 for RX_THRESH Interrupt, 1 for RX Interrupt, 2 + * for TX Interrupt and 3 for MISC Interrupt. + */ + cpdma_ctlr_eoi(priv->dma, value); cpsw_intr_disable(priv); if (priv->irq_enabled == true) { @@ -786,8 +794,6 @@ static int cpsw_poll(struct napi_struct *napi, int budget) int num_tx, num_rx; num_tx = cpdma_chan_process(priv->txch, 128); - if (num_tx) - cpdma_ctlr_eoi(priv->dma, CPDMA_EOI_TX); num_rx = cpdma_chan_process(priv->rxch, budget); if (num_rx < budget) { @@ -795,7 +801,6 @@ static int cpsw_poll(struct napi_struct *napi, int budget) napi_complete(napi); cpsw_intr_enable(priv); - cpdma_ctlr_eoi(priv->dma, CPDMA_EOI_RX); prim_cpsw = cpsw_get_slave_priv(priv, 0); if (prim_cpsw->irq_enabled == false) { prim_cpsw->irq_enabled = true; @@ -1310,8 +1315,6 @@ static int cpsw_ndo_open(struct net_device *ndev) napi_enable(&priv->napi); cpdma_ctlr_start(priv->dma); cpsw_intr_enable(priv); - cpdma_ctlr_eoi(priv->dma, CPDMA_EOI_RX); - cpdma_ctlr_eoi(priv->dma, CPDMA_EOI_TX); prim_cpsw = cpsw_get_slave_priv(priv, 0); if (prim_cpsw->irq_enabled == false) { @@ -1578,9 +1581,6 @@ static void cpsw_ndo_tx_timeout(struct net_device *ndev) cpdma_chan_start(priv->txch); cpdma_ctlr_int_ctrl(priv->dma, true); cpsw_intr_enable(priv); - cpdma_ctlr_eoi(priv->dma, CPDMA_EOI_RX); - cpdma_ctlr_eoi(priv->dma, CPDMA_EOI_TX); - } static int cpsw_ndo_set_mac_address(struct net_device *ndev, void *p) @@ -1620,9 +1620,6 @@ static void cpsw_ndo_poll_controller(struct net_device *ndev) cpsw_interrupt(ndev->irq, priv); cpdma_ctlr_int_ctrl(priv->dma, true); cpsw_intr_enable(priv); - cpdma_ctlr_eoi(priv->dma, CPDMA_EOI_RX); - cpdma_ctlr_eoi(priv->dma, CPDMA_EOI_TX); - } #endif