From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E977E339874; Tue, 16 Dec 2025 13:00:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765890012; cv=none; b=RU8awzhCciVLPEsSsOmxry3hq40wD438XqONaSWJZjrIi2wVNevjH9Er5t49zfuEBvBYQjliTEfqqsKI16A9h2Xslf9Io1KQEaRYmeTcDD7trWtSlyVkKtvBSVInI3r+5d4w49tJ5aAiF+Ralv+KOpvH+5/sSTtb04kPEYiseK4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765890012; c=relaxed/simple; bh=mQBluV4vo6oktVQMR47MWjsZkZHvF2VHMeD3tqW78+Y=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ixXeHfbuFKK+5n3BrvNZYDNvh99QjjE76B/RRgAAoM9hPDwWMiqJ3m13jDQoBKnm5v9u8J6kNOkAIIbJaydCwVgoAa+H/zf4k1hjATfxEETS6+4aQ2r8/mlxyZpi6PweM+AQjzvA9mnQtMvgcaT1pG7insxGj+wbi98bmsfjxlg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=d/mH6mX0; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="d/mH6mX0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1E575C4CEF1; Tue, 16 Dec 2025 13:00:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765890011; bh=mQBluV4vo6oktVQMR47MWjsZkZHvF2VHMeD3tqW78+Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=d/mH6mX0eV2p9m7sYxhd3qcf37tLj1VmfJt7vEv1GsrZWMEkcY1dHcUW73Z60Nzds cWCIqM4gY0hwzYxK5rT52lPxMBFfIv9esPpLkPVpFRQp6t56HAnArMzaOtuxGZzxft OsMqKHkYP1TwMTdsFqEHM3Usjhg475XALpCMK/pUFaGAW20gLipDJqU0UCzratyv7N mBXvX6HS9s+6xpRIeGW/mgZOqB8vCGfvvkH1Rdt1jDmBVC0kV02cbZ6vClscrWkzc9 sFBlYPqiOSqMahw2Yz3H2ISEjmR68Q0yTx2t02J/BlYQldHlj5cMMqYA/kx1J52gk7 BUSGWdUOsjmRQ== Date: Tue, 16 Dec 2025 18:30:07 +0530 From: Vinod Koul To: Bartosz Golaszewski Cc: Jonathan Corbet , Thara Gopinath , Herbert Xu , "David S. Miller" , Udit Tiwari , Daniel Perez-Zoghbi , Md Sadre Alam , Dmitry Baryshkov , dmaengine@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-crypto@vger.kernel.org, Bartosz Golaszewski Subject: Re: [PATCH v9 03/11] dmaengine: qcom: bam_dma: implement support for BAM locking Message-ID: References: <20251128-qcom-qce-cmd-descr-v9-0-9a5f72b89722@linaro.org> <20251128-qcom-qce-cmd-descr-v9-3-9a5f72b89722@linaro.org> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251128-qcom-qce-cmd-descr-v9-3-9a5f72b89722@linaro.org> On 28-11-25, 12:44, Bartosz Golaszewski wrote: > From: Bartosz Golaszewski > > Use metadata operations in DMA descriptors to allow BAM users to pass > additional information to the engine. To that end: define a new > structure - struct bam_desc_metadata - as a medium and define two new > commands: for locking and unlocking the BAM respectively. Handle the > locking in the .attach() callback. > > Signed-off-by: Bartosz Golaszewski > --- > drivers/dma/qcom/bam_dma.c | 59 +++++++++++++++++++++++++++++++++++++++- > include/linux/dma/qcom_bam_dma.h | 12 ++++++++ > 2 files changed, 70 insertions(+), 1 deletion(-) > > diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c > index c9ae1fffe44d79c5eb59b8bbf7f147a8fa3aa0bd..d1dc80b29818897b333cd223ec7306a169cc51fd 100644 > --- a/drivers/dma/qcom/bam_dma.c > +++ b/drivers/dma/qcom/bam_dma.c > @@ -30,6 +30,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -391,6 +392,8 @@ struct bam_chan { > struct list_head desc_list; > > struct list_head node; > + > + bool bam_locked; > }; > > static inline struct bam_chan *to_bam_chan(struct dma_chan *common) > @@ -655,6 +658,53 @@ static int bam_slave_config(struct dma_chan *chan, > return 0; > } > > +static int bam_metadata_attach(struct dma_async_tx_descriptor *desc, void *data, size_t len) > +{ > + struct virt_dma_desc *vd = container_of(desc, struct virt_dma_desc, tx); > + struct bam_async_desc *async_desc = container_of(vd, struct bam_async_desc, vd); > + struct bam_desc_hw *hw_desc = async_desc->desc; > + struct bam_desc_metadata *metadata = data; > + struct bam_chan *bchan = to_bam_chan(metadata->chan); > + struct bam_device *bdev = bchan->bdev; > + > + if (!data) > + return -EINVAL; > + > + if (metadata->op == BAM_META_CMD_LOCK || metadata->op == BAM_META_CMD_UNLOCK) { > + if (!bdev->dev_data->bam_pipe_lock) > + return -EOPNOTSUPP; > + > + /* Expecting a dummy write when locking, only one descriptor allowed. */ > + if (async_desc->num_desc != 1) > + return -EINVAL; > + } > + > + switch (metadata->op) { > + case BAM_META_CMD_LOCK: > + if (bchan->bam_locked) > + return -EBUSY; > + > + hw_desc->flags |= DESC_FLAG_LOCK; Why does this flag imply for the hardware. I do not like the interface designed here. This is overloading. Can we look at doing something better here. -- ~Vinod