From nobody Wed Dec 31 21:40:12 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0D88C4332F for ; Sun, 29 Oct 2023 17:01:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230185AbjJ2RBX (ORCPT ); Sun, 29 Oct 2023 13:01:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41020 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230207AbjJ2RBU (ORCPT ); Sun, 29 Oct 2023 13:01:20 -0400 Received: from hutie.ust.cz (hutie.ust.cz [IPv6:2a03:3b40:fe:f0::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 60517F1; Sun, 29 Oct 2023 10:01:14 -0700 (PDT) From: =?UTF-8?q?Martin=20Povi=C5=A1er?= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cutebit.org; s=mail; t=1698598869; bh=3obvFsIjM96yZObtxW8n9rYv9PO/4hd8o4iHKP3fPHU=; h=From:To:Cc:Subject:Date; b=oy969q+11rxbPH9cmRXxn2HzOTPuGmb0VMsz2ddR9KK/ynvf7bXNiYZ59vwv4s2By i0bAABtuznqJQtxeSHwIhKUpL9GgtlZLi2tLJi4Es2OLo/FehsMGXHRSPmEROM6Cj2 9/C9VVpp43XUb2TQFXhnEdPFw/Geu2MCQp+l5uZE= To: Hector Martin , Sven Peter , Vinod Koul Cc: Alyssa Rosenzweig , asahi@lists.linux.dev, linux-arm-kernel@lists.infradead.org, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, =?UTF-8?q?Martin=20Povi=C5=A1er?= Subject: [PATCH] dmaengine: apple-admac: Keep upper bits of REG_BUS_WIDTH Date: Sun, 29 Oct 2023 18:00:53 +0100 Message-Id: <20231029170053.82146-1-povik+lin@cutebit.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Hector Martin For RX channels, REG_BUS_WIDTH seems to default to a value of 0xf00, and macOS preserves the upper bits when setting the configuration in the lower ones. If we reset the upper bits to 0, this causes framing errors on suspend/resume (the data stream "tears" and channels get swapped around). Keeping the upper bits untouched, like the macOS driver does, fixes this issue. Signed-off-by: Hector Martin Reviewed-by: Martin Povi=C5=A1er Signed-off-by: Martin Povi=C5=A1er --- drivers/dma/apple-admac.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/dma/apple-admac.c b/drivers/dma/apple-admac.c index 5b63996640d9..9588773dd2eb 100644 --- a/drivers/dma/apple-admac.c +++ b/drivers/dma/apple-admac.c @@ -57,6 +57,8 @@ =20 #define REG_BUS_WIDTH(ch) (0x8040 + (ch) * 0x200) =20 +#define BUS_WIDTH_WORD_SIZE GENMASK(3, 0) +#define BUS_WIDTH_FRAME_SIZE GENMASK(7, 4) #define BUS_WIDTH_8BIT 0x00 #define BUS_WIDTH_16BIT 0x01 #define BUS_WIDTH_32BIT 0x02 @@ -740,7 +742,8 @@ static int admac_device_config(struct dma_chan *chan, struct admac_data *ad =3D adchan->host; bool is_tx =3D admac_chan_direction(adchan->no) =3D=3D DMA_MEM_TO_DEV; int wordsize =3D 0; - u32 bus_width =3D 0; + u32 bus_width =3D readl_relaxed(ad->base + REG_BUS_WIDTH(adchan->no)) & + ~(BUS_WIDTH_WORD_SIZE | BUS_WIDTH_FRAME_SIZE); =20 switch (is_tx ? config->dst_addr_width : config->src_addr_width) { case DMA_SLAVE_BUSWIDTH_1_BYTE: --=20 2.38.3