Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752900AbcLHJqj (ORCPT ); Thu, 8 Dec 2016 04:46:39 -0500 Received: from bes.se.axis.com ([195.60.68.10]:60487 "EHLO bes.se.axis.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752220AbcLHJqh (ORCPT ); Thu, 8 Dec 2016 04:46:37 -0500 Subject: Re: [PATCH v3 3/6] net: stmmac: stmmac_platform: fix parsing of DT binding To: Alexandre Torgue , 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> CC: , From: Niklas Cassel Message-ID: <3f1ee075-0c21-f162-451d-e87882f8f55e@axis.com> Date: Thu, 8 Dec 2016 10:46:33 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Icedove/45.4.0 MIME-Version: 1.0 In-Reply-To: <62474778-78da-d34e-bc36-022b2206a8db@st.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.0.5.60] X-ClientProxiedBy: XBOX04.axis.com (10.0.5.18) To XBOX02.axis.com (10.0.5.16) X-TM-AS-GCONF: 00 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4489 Lines: 104 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. > > >> + 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; >>