Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753019AbcLHJya (ORCPT ); Thu, 8 Dec 2016 04:54:30 -0500 Received: from mx07-00178001.pphosted.com ([62.209.51.94]:17181 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751639AbcLHJy1 (ORCPT ); Thu, 8 Dec 2016 04:54:27 -0500 Subject: Re: [PATCH v3 3/6] net: stmmac: stmmac_platform: fix parsing of DT binding To: Niklas Cassel , Giuseppe Cavallaro References: <1481120409-18103-1-git-send-email-niklass@axis.com> <1481120409-18103-4-git-send-email-niklass@axis.com> <62474778-78da-d34e-bc36-022b2206a8db@st.com> <3f1ee075-0c21-f162-451d-e87882f8f55e@axis.com> CC: , From: Alexandre Torgue Message-ID: <90ea49d4-91de-0a5b-d379-11c60b6ccb73@st.com> Date: Thu, 8 Dec 2016 10:54:20 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <3f1ee075-0c21-f162-451d-e87882f8f55e@axis.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.48.0.2] X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-12-08_05:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4716 Lines: 114 Hi On 12/08/2016 10:46 AM, Niklas Cassel wrote: > On 12/08/2016 10:02 AM, Alexandre Torgue wrote: >> Hi Niklas >> >> On 12/07/2016 03:20 PM, Niklas Cassel wrote: >>> From: Niklas Cassel >>> >>> commit 64c3b252e9fc ("net: stmmac: fixed the pbl setting with DT") >>> changed the parsing of the DT binding. >>> >>> Before 64c3b252e9fc, snps,fixed-burst and snps,mixed-burst were parsed >>> regardless if the property snps,pbl existed or not. >>> After the commit, fixed burst and mixed burst are only parsed if >>> snps,pbl exists. Now when snps,aal has been added, it too is only >>> parsed if snps,pbl exists. >>> >>> Since the DT binding does not specify that fixed burst, mixed burst >>> or aal depend on snps,pbl being specified, undo changes introduced >>> by 64c3b252e9fc. >>> >>> The issue commit 64c3b252e9fc ("net: stmmac: fixed the pbl setting with >>> DT") tries to address is solved in another way: >>> The databook specifies that all values other than >>> 1, 2, 4, 8, 16, or 32 results in undefined behavior, >>> so snps,pbl = <0> is invalid. >>> >>> If pbl is 0 after parsing, set pbl to DEFAULT_DMA_PBL. >>> This handles the case where the property is omitted, and also handles >>> the case where the property is specified without any data. >>> >>> Signed-off-by: Niklas Cassel >>> --- >>> drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 +-- >>> .../net/ethernet/stmicro/stmmac/stmmac_platform.c | 29 +++++++++++----------- >>> 2 files changed, 17 insertions(+), 16 deletions(-) >>> >>> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c >>> index b1e42ddf0370..b5188122bc15 100644 >>> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c >>> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c >>> @@ -1581,8 +1581,8 @@ static int stmmac_init_dma_engine(struct stmmac_priv *priv) >>> int atds = 0; >>> int ret = 0; >>> >>> - if (!priv->plat->dma_cfg) { >>> - dev_err(priv->device, "DMA configuration not found\n"); >>> + if (!priv->plat->dma_cfg || !priv->plat->dma_cfg->pbl) { >> >> How "priv->plat->dma_cfg->pbl" could be equal to 0 if you force it to DEFAULT_DMA_PBL in "stmmac_probe_config_dt" in case of DT doesn't set pbl value? > > The PCI glue code does not call stmmac_probe_config_dt. > > Also any glue driver could override the value set by stmmac_probe_config_dt > before calling stmmac_dvr_probe. So I guess if we want any trustworthy > sanity-checking, it actually has to be done in stmmac_main.c. Ok I see, it is more safe. You can add my Acked-by. Thanks Alex > > >> >> >>> + dev_err(priv->device, "Invalid DMA configuration\n"); >>> return -EINVAL; >>> } >>> >>> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c >>> index d3b6f92f350a..81800f23a9c4 100644 >>> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c >>> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c >>> @@ -304,21 +304,22 @@ stmmac_probe_config_dt(struct platform_device *pdev, const char **mac) >>> plat->force_sf_dma_mode = 1; >>> } >>> >>> - if (of_find_property(np, "snps,pbl", NULL)) { >>> - dma_cfg = devm_kzalloc(&pdev->dev, sizeof(*dma_cfg), >>> - GFP_KERNEL); >>> - if (!dma_cfg) { >>> - stmmac_remove_config_dt(pdev, plat); >>> - return ERR_PTR(-ENOMEM); >>> - } >>> - plat->dma_cfg = dma_cfg; >>> - of_property_read_u32(np, "snps,pbl", &dma_cfg->pbl); >>> - dma_cfg->aal = of_property_read_bool(np, "snps,aal"); >>> - dma_cfg->fixed_burst = >>> - of_property_read_bool(np, "snps,fixed-burst"); >>> - dma_cfg->mixed_burst = >>> - of_property_read_bool(np, "snps,mixed-burst"); >>> + dma_cfg = devm_kzalloc(&pdev->dev, sizeof(*dma_cfg), >>> + GFP_KERNEL); >>> + if (!dma_cfg) { >>> + stmmac_remove_config_dt(pdev, plat); >>> + return ERR_PTR(-ENOMEM); >>> } >>> + plat->dma_cfg = dma_cfg; >>> + >>> + of_property_read_u32(np, "snps,pbl", &dma_cfg->pbl); >>> + if (!dma_cfg->pbl) >>> + dma_cfg->pbl = DEFAULT_DMA_PBL; >>> + >>> + dma_cfg->aal = of_property_read_bool(np, "snps,aal"); >>> + dma_cfg->fixed_burst = of_property_read_bool(np, "snps,fixed-burst"); >>> + dma_cfg->mixed_burst = of_property_read_bool(np, "snps,mixed-burst"); >>> + >>> plat->force_thresh_dma_mode = of_property_read_bool(np, "snps,force_thresh_dma_mode"); >>> if (plat->force_thresh_dma_mode) { >>> plat->force_sf_dma_mode = 0; >>> >