From nobody Wed Nov 27 02:35:51 2024 Received: from mx07-00178001.pphosted.com (mx07-00178001.pphosted.com [185.132.182.106]) (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 755E21EC004; Tue, 15 Oct 2024 12:16:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.132.182.106 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728994590; cv=none; b=ppV99MGt7AT8SVp9R6Gl8eg1lWbiBTTN5i5nJaLlo8tNWY8gFSX0ItLw9mgt6XHDdLmzCaKZu49FzlOITVY6DAJ8N2MvcbpJusgHD2hJd2ITUIH7rK4v0gTmxlXNMK3vNpaWVF1l/B3/NEuZCZ/Xitl7psTnAboAnceFmI+E1Ko= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728994590; c=relaxed/simple; bh=dJQWkcrhwk0Vkj1AihIMxNRLDfQsHXxazUmkVVKOLlY=; h=From:Date:Subject:MIME-Version:Content-Type:Message-ID:References: In-Reply-To:To:CC; b=OMBK7KOoOZHZX//V6K6mVEf+ftuPfQ8638KmY0rJx/Lt/2+VnIigeIED5+R5dcf6ZYqw3E8g7eoowgCbQ2pCKbXUZzXcM/lfvWkI8b8xxk8p+UWIbPD41MHUZOjajGJpjWnpVxJhY7BDYkJ1NButKGKOjzz3ksRIxqvkKcMegC4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=foss.st.com; spf=pass smtp.mailfrom=foss.st.com; dkim=pass (2048-bit key) header.d=foss.st.com header.i=@foss.st.com header.b=i+EpCeJP; arc=none smtp.client-ip=185.132.182.106 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=foss.st.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=foss.st.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=foss.st.com header.i=@foss.st.com header.b="i+EpCeJP" Received: from pps.filterd (m0241204.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 49F8bYfA027894; Tue, 15 Oct 2024 14:16:16 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foss.st.com; h= cc:content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=selector1; bh= 1FmGrSANQn07iSNnWCRz9WCfIaMI09hSsfRbqu2gnOU=; b=i+EpCeJP2v5lQoKP 7wHXFfPiAb0MUdQuYdomotUyZGBeM3pWQhTsJz7KvjBqh8qg+8N7owPlycG9D/Uh l5akDnfr+1U+B81/BrulzujahyC1ij3h5eEUPTtyJXuXHuiJdzKxHGTEY+o2DA02 ek3J2DIa+YrcnoETc85jrpccnTkJHlsDi6S22hsFiZ8KMQG86vTdoJD3t7OGF0p6 hd0fY84V4HJpfbiIngHCdXo/1tQUnG/5hamgUBJJquiBrNYQT3a8IvcS92V6c5sY cy8mobAO4dO7ccFKQuvAjGk6P3McC9T+zTaHVInYrwTG+OR/IFd9gFMIPb6ebkf1 jQV8zQ== Received: from beta.dmz-ap.st.com (beta.dmz-ap.st.com [138.198.100.35]) by mx07-00178001.pphosted.com (PPS) with ESMTPS id 427gewwakg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 15 Oct 2024 14:16:16 +0200 (MEST) Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-ap.st.com (STMicroelectronics) with ESMTP id 084CB4004F; Tue, 15 Oct 2024 14:15:28 +0200 (CEST) Received: from Webmail-eu.st.com (shfdag1node3.st.com [10.75.129.71]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 4CA2322233B; Tue, 15 Oct 2024 14:14:47 +0200 (CEST) Received: from localhost (10.48.87.35) by SHFDAG1NODE3.st.com (10.75.129.71) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.37; Tue, 15 Oct 2024 14:14:47 +0200 From: Amelie Delaunay Date: Tue, 15 Oct 2024 14:14:37 +0200 Subject: [PATCH v2 1/9] dt-bindings: dma: stm32-dma3: prevent packing/unpacking mode Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-ID: <20241015-dma3-mp25-updates-v2-1-b63e21556ec8@foss.st.com> References: <20241015-dma3-mp25-updates-v2-0-b63e21556ec8@foss.st.com> In-Reply-To: <20241015-dma3-mp25-updates-v2-0-b63e21556ec8@foss.st.com> To: Vinod Koul , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Maxime Coquelin , Alexandre Torgue CC: , , , , , Amelie Delaunay X-Mailer: b4 0.14.2 X-ClientProxiedBy: EQNCAS1NODE4.st.com (10.75.129.82) To SHFDAG1NODE3.st.com (10.75.129.71) X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.680,FMLib:17.12.60.29 definitions=2024-09-06_09,2024-09-06_01,2024-09-02_01 When source data width/burst and destination data width/burst are different, data are packed or unpacked in DMA3 channel FIFO. Data are pushed out from DMA3 channel FIFO when the destination burst length (=3D data width * burst) is reached. If the channel is stopped before the transfer end, and if some bytes are packed/unpacked in the DMA3 channel FIFO, these bytes are lost. Indeed, DMA3 channel FIFO has no flush capability, only reset. To avoid potential bytes lost, pack/unpack must be prevented by setting memory data width/burst equal to peripheral data width/burst. Memory accesses will be penalized. But it is the only way to avoid bytes lost. Some devices (e.g. cyclic RX like UART) need this, so add the possibility to prevent pack/unpack feature, by setting bit 16 of the 'DMA transfer requirements' bit mask. Acked-by: Rob Herring (Arm) Signed-off-by: Amelie Delaunay --- Documentation/devicetree/bindings/dma/stm32/st,stm32-dma3.yaml | 3 +++ 1 file changed, 3 insertions(+) diff --git a/Documentation/devicetree/bindings/dma/stm32/st,stm32-dma3.yaml= b/Documentation/devicetree/bindings/dma/stm32/st,stm32-dma3.yaml index 7fdc44b2e6467928622a5bb25d9e0c74bb1790ae..5484848735f8ac3d2050104bbab= 1d986e82ba6a7 100644 --- a/Documentation/devicetree/bindings/dma/stm32/st,stm32-dma3.yaml +++ b/Documentation/devicetree/bindings/dma/stm32/st,stm32-dma3.yaml @@ -96,6 +96,9 @@ properties: including the update of the LLI if any 0x3: at channel level, the transfer complete event is generated = at the end of the last LLI + -bit 16: Prevent packing/unpacking mode + 0x0: pack/unpack enabled when source data width/burst !=3D desti= nation data width/burst + 0x1: memory data width/burst forced to peripheral data width/bur= st to prevent pack/unpack =20 required: - compatible --=20 2.25.1