From nobody Thu Oct 2 00:49:07 2025 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 5147730B51F for ; Wed, 24 Sep 2025 15:03:07 +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=1758726190; cv=none; b=KgEKJBll9YoVjqoJIsAD2VPlDpi37nfn21K/iNYvg6A7TLV5Y0/Tg0EfdY2c5aX+M3bZuhqSGs+wm8fxtxjpX3nNMYTTwclHTHc2O8O6UsuhrsXk9P6NkEzCH9+rrRE+tSjTj3O/DZ0JnVJ30RsPM+lL4feuSJlAbprx1oXW7tM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758726190; c=relaxed/simple; bh=NHdaRaD3D0V/u38JlJWZFkww+I34dCOx77Sm+WqQ4E4=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=hw0NO0GLMPOYoVzDpQzTx+5cS1vgAX7KJKaFIFLUl4EnX6CP1MYkhiP90Uw9NiML5g/FJtYbEODkGYU1i8LnhGh2meEKxXUboei9lSYljaym3xrYqHsnzMb2I61TD0KA1Yw237Zxkp1pgz4xiKABzIgYQ57SZlxq5xRBoMmFHGY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oqUjFlZ9; 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="oqUjFlZ9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 07A9EC4CEE7; Wed, 24 Sep 2025 15:03:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758726187; bh=NHdaRaD3D0V/u38JlJWZFkww+I34dCOx77Sm+WqQ4E4=; h=From:To:Cc:Subject:Date:From; b=oqUjFlZ9Gv5Em/Ipd0DIbSyJNrIXgyjvqXFpcVeFsMHJP+hAPQGVdXyBnDJEQ2evu jFEXm7AtkfUTpC6bLNBtY770dMIB+mFc2qqH54sJA1ESdf/292x688Ln1PYnCUJOhC LbxRwAngvm4IoYZyYTwkJ8aVUCwW2N30xFYPMG3FR5Zh7x7AkiUh+eal5BeezD+uwT 2W51kiodc7aI/PuFTTbC/IxB7cKPU5CfyRTeth398J6pGJVVIXeUfu02sQ8EHsuCzz FgMz0kHeo/LCtn/XQVRI01tbY9J8dAHQsYOsocyYk198KBDgBBk3qYZ3S5sX6BdDgF iOEcIpMLQFRSg== From: Arnd Bergmann To: Alexandre Belloni , Wolfram Sang , Jorge Marques , Frank Li Cc: Arnd Bergmann , Manikanta Guntupalli , linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] i3c: fix big-endian FIFO transfers Date: Wed, 24 Sep 2025 17:02:53 +0200 Message-Id: <20250924150303.3601429-1-arnd@kernel.org> X-Mailer: git-send-email 2.39.5 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Arnd Bergmann Short MMIO transfers that are not a multiple of four bytes in size need a special case for the final bytes, however the existing implementation is not endian-safe and introduces an incorrect byteswap on big-endian kernels. This usually does not cause problems because most systems are little-endian and most transfers are multiple of four bytes long, but still needs to be fixed to avoid the extra byteswap. Change the special case for both i3c_writel_fifo() and i3c_readl_fifo() to use non-byteswapping writesl() and readsl() with a single element instead of the byteswapping writel()/readl() that are meant for individual MMIO registers. The earlier versions in the dw-i3c and i3c-master-cdns had a correct implementation, but the generic version that was recently added broke it. Fixes: 733b439375b4 ("i3c: master: Add inline i3c_readl_fifo() and i3c_writ= el_fifo()") Cc: Manikanta Guntupalli Signed-off-by: Arnd Bergmann --- This was a recent regression, the version in 6.16 still works, but 6.17-rc is broken. --- drivers/i3c/internals.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/i3c/internals.h b/drivers/i3c/internals.h index 0d857cc68cc5..0f8a25cb71e7 100644 --- a/drivers/i3c/internals.h +++ b/drivers/i3c/internals.h @@ -38,7 +38,7 @@ static inline void i3c_writel_fifo(void __iomem *addr, co= nst void *buf, u32 tmp =3D 0; =20 memcpy(&tmp, buf + (nbytes & ~3), nbytes & 3); - writel(tmp, addr); + writesl(addr, &buf, 1); } } =20 @@ -55,7 +55,7 @@ static inline void i3c_readl_fifo(const void __iomem *add= r, void *buf, if (nbytes & 3) { u32 tmp; =20 - tmp =3D readl(addr); + readsl(addr, &tmp, 1); memcpy(buf + (nbytes & ~3), &tmp, nbytes & 3); } } --=20 2.39.5