From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jakub =?UTF-8?B?S2ljacWEc2tp?= Subject: Re: [PATCH 4/4] bgmac: fix DMA rx corruption Date: Sun, 12 Apr 2015 12:31:34 +0200 Message-ID: <20150412123134.3e1c4fea@north> References: <1428833292-15356-1-git-send-email-nbd@openwrt.org> <1428833292-15356-4-git-send-email-nbd@openwrt.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, zajec5@gmail.com, hauke@hauke-m.de To: Felix Fietkau Return-path: Received: from mx3.wp.pl ([212.77.101.10]:28285 "EHLO mx3.wp.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751237AbbDLKiQ (ORCPT ); Sun, 12 Apr 2015 06:38:16 -0400 In-Reply-To: <1428833292-15356-4-git-send-email-nbd@openwrt.org> Sender: netdev-owner@vger.kernel.org List-ID: On Sun, 12 Apr 2015 12:08:12 +0200, Felix Fietkau wrote: > The driver needs to inform the hardware about the first invalid (not yet > filled) rx slot, by writing its DMA descriptor pointer offset to the > BGMAC_DMA_RX_INDEX register. > > This register was set to a value exceeding the rx ring size, effectively > allowing the hardware constant access to the full ring, regardless of > which slots are initialized. > > Fix this by updating the register in bgmac_dma_rx_setup_desc. > > Signed-off-by: Felix Fietkau > --- > drivers/net/ethernet/broadcom/bgmac.c | 14 +++++++------- > 1 file changed, 7 insertions(+), 7 deletions(-) > > diff --git a/drivers/net/ethernet/broadcom/bgmac.c b/drivers/net/ethernet/broadcom/bgmac.c > index e332de8..856ceee 100644 > --- a/drivers/net/ethernet/broadcom/bgmac.c > +++ b/drivers/net/ethernet/broadcom/bgmac.c > @@ -380,6 +380,12 @@ static void bgmac_dma_rx_setup_desc(struct bgmac *bgmac, > dma_desc->addr_high = cpu_to_le32(upper_32_bits(ring->slots[desc_idx].dma_addr)); > dma_desc->ctl0 = cpu_to_le32(ctl0); > dma_desc->ctl1 = cpu_to_le32(ctl1); > + > + desc_idx = (desc_idx + 1) % BGMAC_RX_RING_SLOTS; > + > + bgmac_write(bgmac, ring->mmio_base + BGMAC_DMA_RX_INDEX, > + ring->index_base + > + desc_idx * sizeof(struct bgmac_dma_desc)); > } Newb question if I may: why is no mem barrier necessary in this case?