Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932763AbcK2Ju4 (ORCPT ); Tue, 29 Nov 2016 04:50:56 -0500 Received: from mail-io0-f172.google.com ([209.85.223.172]:33100 "EHLO mail-io0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756576AbcK2Jul (ORCPT ); Tue, 29 Nov 2016 04:50:41 -0500 MIME-Version: 1.0 In-Reply-To: References: From: Marcin Wojtas Date: Tue, 29 Nov 2016 10:50:39 +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 Content-Length: 8646 Lines: 205 Hi Gregory, Apparently HWBM had a mistake in implementation, please see below. 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; > > dma_unmap_single(pp->dev->dev.parent, rx_desc->buf_phys_addr, > MVNETA_RX_BUF_SIZE(pp->pkt_size), DMA_FROM_DEVICE); > @@ -1894,12 +1907,13 @@ static int mvneta_rx_swbm(struct mvneta_port *pp, int rx_todo, > unsigned char *data; > dma_addr_t phys_addr; > u32 rx_status, frag_size; > - int rx_bytes, err; > + int rx_bytes, err, index; > > rx_done++; > rx_status = rx_desc->status; > rx_bytes = rx_desc->data_size - (ETH_FCS_LEN + MVNETA_MH_SIZE); > - data = (unsigned char *)rx_desc->buf_cookie; > + index = rx_desc - rxq->descs; > + data = (unsigned char *)rxq->buf_virt_addr[index]; > phys_addr = rx_desc->buf_phys_addr; > > if (!mvneta_rxq_desc_is_first_last(rx_status) || > @@ -1938,7 +1952,7 @@ static int mvneta_rx_swbm(struct mvneta_port *pp, int rx_todo, > } > > /* Refill processing */ > - err = mvneta_rx_refill(pp, rx_desc); > + err = mvneta_rx_refill(pp, rx_desc, rxq); > if (err) { > netdev_err(dev, "Linux processing - Can't refill\n"); > rxq->missed++; > @@ -2020,7 +2034,7 @@ static int mvneta_rx_hwbm(struct mvneta_port *pp, int rx_todo, > rx_done++; > rx_status = rx_desc->status; > rx_bytes = rx_desc->data_size - (ETH_FCS_LEN + MVNETA_MH_SIZE); > - data = (unsigned char *)rx_desc->buf_cookie; > + data = (u8 *)(uintptr_t)rx_desc->buf_cookie; > phys_addr = rx_desc->buf_phys_addr; > pool_id = MVNETA_RX_GET_BM_POOL_ID(rx_desc); > bm_pool = &pp->bm_priv->bm_pools[pool_id]; > @@ -2708,6 +2722,56 @@ static int mvneta_poll(struct napi_struct *napi, int budget) > return rx_done; > } > > +/* Refill processing for HW buffer management */ > +static int mvneta_rx_hwbm_refill(struct mvneta_port *pp, > + struct mvneta_rx_desc *rx_desc) > + > +{ > + dma_addr_t phys_addr; > + void *data; > + > + data = mvneta_frag_alloc(pp->frag_size); > + if (!data) > + return -ENOMEM; > + > + phys_addr = dma_map_single(pp->dev->dev.parent, data, > + MVNETA_RX_BUF_SIZE(pp->pkt_size), > + DMA_FROM_DEVICE); > + if (unlikely(dma_mapping_error(pp->dev->dev.parent, phys_addr))) { > + mvneta_frag_free(pp->frag_size, data); > + return -ENOMEM; > + } > + > + rx_desc->buf_phys_addr = phys_addr; > + rx_desc->buf_cookie = (uintptr_t)data; > + > + return 0; > +} > + > +/* Handle rxq fill: allocates rxq skbs; called when initializing a port */ > +static int mvneta_rxq_bm_fill(struct mvneta_port *pp, > + struct mvneta_rx_queue *rxq, > + int num) > +{ > + int i; > + > + for (i = 0; i < num; i++) { > + memset(rxq->descs + i, 0, sizeof(struct mvneta_rx_desc)); > + if (mvneta_rx_hwbm_refill(pp, rxq->descs + i) != 0) { > + netdev_err(pp->dev, "%s:rxq %d, %d of %d buffs filled\n", > + __func__, rxq->id, i, num); > + break; > + } > + } > + > + /* Add this number of RX descriptors as non occupied (ready to > + * get packets) > + */ > + mvneta_rxq_non_occup_desc_add(pp, rxq, i); > + > + return i; > +} > + > /* Handle rxq fill: allocates rxq skbs; called when initializing a port */ > static int mvneta_rxq_fill(struct mvneta_port *pp, struct mvneta_rx_queue *rxq, > int num) > @@ -2716,7 +2780,7 @@ static int mvneta_rxq_fill(struct mvneta_port *pp, struct mvneta_rx_queue *rxq, > > for (i = 0; i < num; i++) { > memset(rxq->descs + i, 0, sizeof(struct mvneta_rx_desc)); > - if (mvneta_rx_refill(pp, rxq->descs + i) != 0) { > + if (mvneta_rx_refill(pp, rxq->descs + i, rxq) != 0) { > netdev_err(pp->dev, "%s:rxq %d, %d of %d buffs filled\n", > __func__, rxq->id, i, num); > break; > @@ -2784,14 +2848,14 @@ static int mvneta_rxq_init(struct mvneta_port *pp, > mvneta_rxq_buf_size_set(pp, rxq, > MVNETA_RX_BUF_SIZE(pp->pkt_size)); > mvneta_rxq_bm_disable(pp, rxq); > + mvneta_rxq_fill(pp, rxq, rxq->size); > } else { > mvneta_rxq_bm_enable(pp, rxq); > mvneta_rxq_long_pool_set(pp, rxq); > mvneta_rxq_short_pool_set(pp, rxq); > + mvneta_rxq_bm_fill(pp, rxq, rxq->size); Manual filling descriptors with new buffers is redundant. For HWBM, all buffers are allocated in mvneta_bm_construct() and in runtime they are put into descriptors by hardware. I think it's enough to add here: mvneta_rxq_non_occup_desc_add(pp, rxq, rxq->size); And remove mvneta_rxq_bm_fill and mvneta_rx_hwbm_refill. Best regards, Marcin