From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756540AbcK2J7v (ORCPT ); Tue, 29 Nov 2016 04:59:51 -0500 Received: from mail-io0-f169.google.com ([209.85.223.169]:34017 "EHLO mail-io0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755261AbcK2J70 (ORCPT ); Tue, 29 Nov 2016 04:59:26 -0500 MIME-Version: 1.0 In-Reply-To: References: From: Marcin Wojtas Date: Tue, 29 Nov 2016 10:59:25 +0100 Message-ID: Subject: Re: [PATCH v3 net-next 2/6] net: mvneta: Use cacheable memory to store the rx buffer virtual address To: Gregory CLEMENT Cc: "David S. Miller" , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Jisheng Zhang , Arnd Bergmann , Jason Cooper , Andrew Lunn , Sebastian Hesselbarth , Thomas Petazzoni , "linux-arm-kernel@lists.infradead.org" , Nadav Haklai , Dmitri Epshtein , Yelena Krivosheev Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Gregory, Another remark below, sorry for noise. 2016-11-29 10:37 GMT+01:00 Gregory CLEMENT : > Until now the virtual address of the received buffer were stored in the > cookie field of the rx descriptor. However, this field is 32-bits only > which prevents to use the driver on a 64-bits architecture. > > With this patch the virtual address is stored in an array not shared with > the hardware (no more need to use the DMA API). Thanks to this, it is > possible to use cache contrary to the access of the rx descriptor member. > > The change is done in the swbm path only because the hwbm uses the cookie > field, this also means that currently the hwbm is not usable in 64-bits. > > Signed-off-by: Gregory CLEMENT > --- > drivers/net/ethernet/marvell/mvneta.c | 93 ++++++++++++++++++++++++---- > 1 file changed, 81 insertions(+), 12 deletions(-) > > diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c > index 1b84f746d748..32b142d0e44e 100644 > --- a/drivers/net/ethernet/marvell/mvneta.c > +++ b/drivers/net/ethernet/marvell/mvneta.c > @@ -561,6 +561,9 @@ struct mvneta_rx_queue { > u32 pkts_coal; > u32 time_coal; > > + /* Virtual address of the RX buffer */ > + void **buf_virt_addr; > + > /* Virtual address of the RX DMA descriptors array */ > struct mvneta_rx_desc *descs; > > @@ -1573,10 +1576,14 @@ static void mvneta_tx_done_pkts_coal_set(struct mvneta_port *pp, > > /* Handle rx descriptor fill by setting buf_cookie and buf_phys_addr */ > static void mvneta_rx_desc_fill(struct mvneta_rx_desc *rx_desc, > - u32 phys_addr, u32 cookie) > + u32 phys_addr, void *virt_addr, > + struct mvneta_rx_queue *rxq) > { > - rx_desc->buf_cookie = cookie; > + int i; > + > rx_desc->buf_phys_addr = phys_addr; > + i = rx_desc - rxq->descs; > + rxq->buf_virt_addr[i] = virt_addr; > } > > /* Decrement sent descriptors counter */ > @@ -1781,7 +1788,8 @@ EXPORT_SYMBOL_GPL(mvneta_frag_free); > > /* Refill processing for SW buffer management */ > static int mvneta_rx_refill(struct mvneta_port *pp, > - struct mvneta_rx_desc *rx_desc) > + struct mvneta_rx_desc *rx_desc, > + struct mvneta_rx_queue *rxq) > > { > dma_addr_t phys_addr; > @@ -1799,7 +1807,7 @@ static int mvneta_rx_refill(struct mvneta_port *pp, > return -ENOMEM; > } > > - mvneta_rx_desc_fill(rx_desc, phys_addr, (u32)data); > + mvneta_rx_desc_fill(rx_desc, phys_addr, data, rxq); > return 0; > } > > @@ -1861,7 +1869,12 @@ static void mvneta_rxq_drop_pkts(struct mvneta_port *pp, > > for (i = 0; i < rxq->size; i++) { > struct mvneta_rx_desc *rx_desc = rxq->descs + i; > - void *data = (void *)rx_desc->buf_cookie; > + void *data; > + > + if (!pp->bm_priv) > + data = rxq->buf_virt_addr[i]; > + else > + data = (void *)(uintptr_t)rx_desc->buf_cookie; Dropping packets for HWBM (in fact returning dropped buffers to the pool) is done a couple of lines above. This point will never be reached with HWBM enabled (and it's also incorrect). Best regards, Marcin