From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AC185C54FD0 for ; Thu, 23 Apr 2020 07:07:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8860621655 for ; Thu, 23 Apr 2020 07:07:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587625622; bh=dqOAH6f+q0EsFhUG8mK6iVhk6XGZrFa8diYIKEfHARs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=NdeWLxzQpy50Ok0JTzb8T3DKHXJqSkJ5q7D/DNs4HVCq6nycm9+ldGW1rWJOwM9Bs 6GdwDSqa1ItKFyFA5lq9ALLjD76AFW7ebR8dGJTqNa9nXvHx/nG/nDuBWBHmcVJoOk j6p8VDXSFBULhoAKhr7B3fwXNmHrJkzvnNr1esUE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726448AbgDWHHC (ORCPT ); Thu, 23 Apr 2020 03:07:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:52252 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726027AbgDWHHC (ORCPT ); Thu, 23 Apr 2020 03:07:02 -0400 Received: from localhost (unknown [49.207.59.230]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D4995208E4; Thu, 23 Apr 2020 07:07:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587625621; bh=dqOAH6f+q0EsFhUG8mK6iVhk6XGZrFa8diYIKEfHARs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YWXxvT27gIOMUwaVeCCRelYlSwvfPbErLib5+ZaS+D6wXfO4XdOb9Ew3kYjK4iZz4 dTnTJ91p2Kw+fLQo4f/j1ta5Q3PMBEClBwYOOTWjorHL3eBm5CUKi8DLHEQpIveHSg U0T+P78Jxc4r2EK1rVS1INybje4pUz5lyxCZoFXI= Date: Thu, 23 Apr 2020 12:36:57 +0530 From: Vinod Koul To: Lubomir Rintel Cc: Dan Williams , dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/7] dmaengine: mmp_tdma: Validate the transfer direction Message-ID: <20200423070657.GW72691@vkoul-mobl> References: <20200419164912.670973-1-lkundrak@v3.sk> <20200419164912.670973-4-lkundrak@v3.sk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200419164912.670973-4-lkundrak@v3.sk> Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 19-04-20, 18:49, Lubomir Rintel wrote: > We only support DMA_DEV_TO_MEM and DMA_MEM_TO_DEV. Let's not do > undefined things with other values and reject them. > > Signed-off-by: Lubomir Rintel > --- > drivers/dma/mmp_tdma.c | 37 ++++++++++++++++++++++++++++--------- > 1 file changed, 28 insertions(+), 9 deletions(-) > > diff --git a/drivers/dma/mmp_tdma.c b/drivers/dma/mmp_tdma.c > index d559bb4d6a31d..d574641791598 100644 > --- a/drivers/dma/mmp_tdma.c > +++ b/drivers/dma/mmp_tdma.c > @@ -207,10 +207,17 @@ static int mmp_tdma_config_chan(struct dma_chan *chan) > > mmp_tdma_disable_chan(chan); > > - if (tdmac->dir == DMA_MEM_TO_DEV) > - tdcr = TDCR_DSTDIR_ADDR_HOLD | TDCR_SRCDIR_ADDR_INC; > - else if (tdmac->dir == DMA_DEV_TO_MEM) > + switch (tdmac->dir) { > + case DMA_DEV_TO_MEM: > tdcr = TDCR_SRCDIR_ADDR_HOLD | TDCR_DSTDIR_ADDR_INC; > + break; > + case DMA_MEM_TO_DEV: > + tdcr = TDCR_DSTDIR_ADDR_HOLD | TDCR_SRCDIR_ADDR_INC; > + break; > + default: > + dev_err(tdmac->dev, "invalid transfer direction\n"); > + return -EINVAL; > + } You can use macros is_slave_direction() to validate > if (tdmac->type == MMP_AUD_TDMA) { > tdcr |= TDCR_PACKMOD; > @@ -455,12 +462,18 @@ static struct dma_async_tx_descriptor *mmp_tdma_prep_dma_cyclic( > desc->nxt_desc = tdmac->desc_arr_phys + > sizeof(*desc) * (i + 1); > It would make more sense to use is_slave_direction() and reject up early in the function and proceed only when good :) > - if (direction == DMA_MEM_TO_DEV) { > - desc->src_addr = dma_addr; > - desc->dst_addr = tdmac->dev_addr; > - } else { > + switch (direction) { > + case DMA_DEV_TO_MEM: > desc->src_addr = tdmac->dev_addr; > desc->dst_addr = dma_addr; > + break; > + case DMA_MEM_TO_DEV: > + desc->src_addr = dma_addr; > + desc->dst_addr = tdmac->dev_addr; > + break; > + default: > + dev_err(tdmac->dev, "invalid transfer direction\n"); > + goto err_out; > } > desc->byte_cnt = period_len; > dma_addr += period_len; > @@ -510,14 +523,20 @@ static int mmp_tdma_config_write(struct dma_chan *chan, > { > struct mmp_tdma_chan *tdmac = to_mmp_tdma_chan(chan); > > - if (dir == DMA_DEV_TO_MEM) { > + switch (dir) { > + case DMA_DEV_TO_MEM: > tdmac->dev_addr = dmaengine_cfg->src_addr; > tdmac->burst_sz = dmaengine_cfg->src_maxburst; > tdmac->buswidth = dmaengine_cfg->src_addr_width; > - } else { > + break; > + case DMA_MEM_TO_DEV: > tdmac->dev_addr = dmaengine_cfg->dst_addr; > tdmac->burst_sz = dmaengine_cfg->dst_maxburst; > tdmac->buswidth = dmaengine_cfg->dst_addr_width; > + break; > + default: > + dev_err(tdmac->dev, "invalid transfer direction\n"); > + return -EINVAL; is this required, if you have checked in all _prep() fns then you are guaranteed that this will never hit, right? -- ~Vinod