From mboxrd@z Thu Jan 1 00:00:00 1970 From: Fabio Estevam Subject: [PATCH v2] net: fec: Fix the disabling of RX interrupt Date: Mon, 18 Feb 2013 17:04:55 -0300 Message-ID: <1361217895-17143-1-git-send-email-fabio.estevam@freescale.com> Mime-Version: 1.0 Content-Type: text/plain Cc: , , , , , Fabio Estevam To: Return-path: Received: from co9ehsobe001.messaging.microsoft.com ([207.46.163.24]:21526 "EHLO co9outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757302Ab3BRUIZ (ORCPT ); Mon, 18 Feb 2013 15:08:25 -0500 Sender: netdev-owner@vger.kernel.org List-ID: The correct way to disable FEC RX interrupt is to clean only the FEC_ENET_RXF bit. Since commit dc975382d2e (net: fec: add napi support to improve proformance) FEC_RX_DISABLED_IMASK is being written to the FEC_IMASK register, which also incorrectly sets other bits as per the definitions below: #define FEC_DEFAULT_IMASK (FEC_ENET_TXF | FEC_ENET_RXF | FEC_ENET_MII) #define FEC_RX_DISABLED_IMASK (FEC_DEFAULT_IMASK & (~FEC_ENET_RXF)) This fixes the following kernel crash: Unable to handle kernel NULL pointer dereference at virtual address 00000002 pgd = 80004000 [00000002] *pgd=00000000 Internal error: Oops: 5 [#1] SMP ARM Modules linked in: CPU: 0 Not tainted (3.8.0-rc7-next-20130218+ #1192) PC is at fec_enet_interrupt+0xd0/0x354 LR is at fec_enet_interrupt+0xb8/0x354 pc : [<8034592c>] lr : [<80345914>] psr: 60000193 Signed-off-by: Fabio Estevam --- Changes since v1: - Fix it also inside fec_enet_init and fix the kernel crash. drivers/net/ethernet/freescale/fec.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/freescale/fec.c b/drivers/net/ethernet/freescale/fec.c index 0fe68c4..4eb0201 100644 --- a/drivers/net/ethernet/freescale/fec.c +++ b/drivers/net/ethernet/freescale/fec.c @@ -811,6 +811,7 @@ fec_enet_interrupt(int irq, void *dev_id) struct fec_enet_private *fep = netdev_priv(ndev); uint int_events; irqreturn_t ret = IRQ_NONE; + int reg; do { int_events = readl(fep->hwp + FEC_IEVENT); @@ -821,8 +822,9 @@ fec_enet_interrupt(int irq, void *dev_id) /* Disable the RX interrupt */ if (napi_schedule_prep(&fep->napi)) { - writel(FEC_RX_DISABLED_IMASK, - fep->hwp + FEC_IMASK); + reg = readl(fep->hwp + FEC_IMASK); + reg &= ~FEC_ENET_RXF; + writel(reg, fep->hwp + FEC_IMASK); __napi_schedule(&fep->napi); } } @@ -1598,7 +1600,7 @@ static int fec_enet_init(struct net_device *ndev) struct fec_enet_private *fep = netdev_priv(ndev); struct bufdesc *cbd_base; struct bufdesc *bdp; - int i; + int i, reg; /* Allocate memory for buffer descriptors. */ cbd_base = dma_alloc_coherent(NULL, PAGE_SIZE, &fep->bd_dma, @@ -1628,7 +1630,10 @@ static int fec_enet_init(struct net_device *ndev) ndev->netdev_ops = &fec_netdev_ops; ndev->ethtool_ops = &fec_enet_ethtool_ops; - writel(FEC_RX_DISABLED_IMASK, fep->hwp + FEC_IMASK); + reg = readl(fep->hwp + FEC_IMASK); + reg &= ~FEC_ENET_RXF; + writel(reg, fep->hwp + FEC_IMASK); + netif_napi_add(ndev, &fep->napi, fec_enet_rx_napi, FEC_NAPI_WEIGHT); /* Initialize the receive buffer descriptors. */ -- 1.7.9.5