From nobody Wed Dec 17 13:56:20 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 17A08C77B7F for ; Fri, 12 May 2023 10:48:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240875AbjELKs4 (ORCPT ); Fri, 12 May 2023 06:48:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48238 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240907AbjELKso (ORCPT ); Fri, 12 May 2023 06:48:44 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C15C512EB4 for ; Fri, 12 May 2023 03:48:06 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-b9a7c58ec19so11706023276.2 for ; Fri, 12 May 2023 03:48:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1683888486; x=1686480486; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=y049PmC5C0PnSAgiyWvWPHzKRIJST3guVG5ES+MeGns=; b=vzvkdCR8kM136SsZBU8U6eQlSFq1oB+ZzglgeMJUx1D0MI+o/WQSVOCyw//1P3LZVw npUlZM10hPgXVQ2Cbmr3lZeebUN8Dq/7w4re/xNNrVEEkLgVTQanyAPt3J/qxl47Phag wuurc+OhIsCI3v0IoO8V0okHUzfS0FGRIzDdTTWooGPJwGl8oIsmiPAtSaFkLnDb42V9 b8DR3HLqasuktNv8yBUjuMR4SLdhfbr+/9pa2ApIj/0mcwTdK1LP7S1arT74S1rq/Nxs IQFoe2LN/ptkKD5ZFlVg1wDRkKW4VPHyVVaVC05WFrmDOaBiRbdwfPUroOXRCZ4Wl2Jy J3+w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683888486; x=1686480486; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=y049PmC5C0PnSAgiyWvWPHzKRIJST3guVG5ES+MeGns=; b=KBj4gKlpwXVhLkHIsZX+StmhTeYHPHzVW+fM0l3a9yKDnie4VwGfsKtgJn7CS/2Dk0 zFpK1eOqn3rfguZsoDqN7x/TIKrNaO3WijDn0DFDTuvUew3L0/OCixCKr3AjgpQl74Gb ra/Jg1j8iFETKrW7Eiht4A+fl2neAx7zocMf4SED26Y7I8C8FbwNWYChap0xeCxYPjID G4qjbZ/Q6nGXVivLhnroVzK/T3ikhPOxEqioOS5ULuDtxa4OmSLcFf4Ny0vh5l1DKCxY Asmn7WEZpyEAwTYbgZ2wh7WxNJIv44Ru6efWV3mSqxWap2w1EKxV6muRG0GjhmOBMTbm OU+Q== X-Gm-Message-State: AC+VfDwQUZkws6+KAJuMcbz+bpg3luCp1AMJfyk5wcMn+/vdtwO3t6/t CvWW6mYp5uqf2ArKP9Syxg1Nlz1FHmYg4A== X-Google-Smtp-Source: ACHHUZ79BFgMVJJIcvfFqvQAo8l+zEZEgcjfLxAouTj2iS04W2IVqnCTc6w1YLTXDa6JDILsajqrPA3xjrT+Jw== X-Received: from joychakr.c.googlers.com ([fda3:e722:ac3:cc00:4f:4b78:c0a8:6ea]) (user=joychakr job=sendgmr) by 2002:a05:6902:1890:b0:b96:7676:db4a with SMTP id cj16-20020a056902189000b00b967676db4amr15756188ybb.0.1683888485998; Fri, 12 May 2023 03:48:05 -0700 (PDT) Date: Fri, 12 May 2023 10:47:45 +0000 In-Reply-To: <20230512104746.1797865-1-joychakr@google.com> Mime-Version: 1.0 References: <20230512104746.1797865-1-joychakr@google.com> X-Mailer: git-send-email 2.40.1.606.ga4b1b128d6-goog Message-ID: <20230512104746.1797865-4-joychakr@google.com> Subject: [PATCH v11 3/3] spi: dw: Round of n_bytes to power of 2 From: Joy Chakraborty To: Mark Brown Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, manugautam@google.com, Joy Chakraborty , Andy Shevchenko , Serge Semin Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" n_bytes variable in the driver represents the number of bytes per word that needs to be sent/copied to fifo. Bits/word can be between 8 and 32 bits from the client but in memory they are a power of 2, same is mentioned in spi.h header: " * @bits_per_word: Data transfers involve one or more words; word sizes * like eight or 12 bits are common. In-memory wordsizes are * powers of two bytes (e.g. 20 bit samples use 32 bits). * This may be changed by the device's driver, or left at the * default (0) indicating protocol words are eight bit bytes. * The spi_transfer.bits_per_word can override this for each transfer. " Hence, round of n_bytes to a power of 2 to avoid values like 3 which would generate unalligned/odd accesses to memory/fifo. Fixes: a51acc2400d4 ("spi: dw: Add support for 32-bits max xfer size") Suggested-by: Andy Shevchenko Signed-off-by: Joy Chakraborty Reviewed-by: Serge Semin Tested-by: Serge Semin * tested on Baikal-T1 based system with DW SPI-looped back interface transferring a chunk of data with DFS:8,12,16. --- drivers/spi/spi-dw-core.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c index ae3108c70f50..7778b19bcb6c 100644 --- a/drivers/spi/spi-dw-core.c +++ b/drivers/spi/spi-dw-core.c @@ -426,7 +426,10 @@ static int dw_spi_transfer_one(struct spi_controller *= master, int ret; =20 dws->dma_mapped =3D 0; - dws->n_bytes =3D DIV_ROUND_UP(transfer->bits_per_word, BITS_PER_BYTE); + dws->n_bytes =3D + roundup_pow_of_two(DIV_ROUND_UP(transfer->bits_per_word, + BITS_PER_BYTE)); + dws->tx =3D (void *)transfer->tx_buf; dws->tx_len =3D transfer->len / dws->n_bytes; dws->rx =3D transfer->rx_buf; --=20 2.40.1.606.ga4b1b128d6-goog