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 B39BE31A805; Mon, 13 Oct 2025 15:28:50 +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=1760369330; cv=none; b=R4k5XzLQbB7kmDvofJynMhTvjYWaSRXpZNDONGZR7EP3lsBObmeHdQXTnb1kXD3haJ1B7yASNdu6nCNMPctk9p1qF6CEUpHJ5XilsihpfgbPJre2uuNQN3rbzkmvSzJ+26jRqY1DjxgHuJtlgv5abMUnpTit685F5aWcauOSt7A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760369330; c=relaxed/simple; bh=5zZwYoh/NuQkij9+yefiYZAfwJJW7obrLAZ4chrPKwc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GzOeUo7EfkBb60EOJBCA6yKGjVuA8lISrKLQa/gNuFekpH7eLnqf/4id6pj6g4XtSuFR9o46I/yQj6FDbh8Ec2Tq70+Dlb8ZUAqp2fhqRhB26rii/wmuSXC57MROqRtgk+Jy5gfvCRcSFlmlMSTZOVUwLRYeat56wmBzjSeOR6s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TbGiNPXu; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="TbGiNPXu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF745C4CEFE; Mon, 13 Oct 2025 15:28:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1760369330; bh=5zZwYoh/NuQkij9+yefiYZAfwJJW7obrLAZ4chrPKwc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TbGiNPXufKPjJHqHGhI9QQlb8HCKUI0l9EA7R6iuWExSXdpm4QtjwFCLBaaMFb/7+ k8Im+f6pnrDrx53+c2ZdO35+GCSLUhIR0TM7uic8IHkgKMSwXr0UUki4GIo9Zx9RMw /yqsl+XTzdRpvuaj5R2fyRuxrjJBpSMfm6KD3c3g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Manikanta Guntupalli , Arnd Bergmann , Jorge Marques , Alexandre Belloni , Sasha Levin Subject: [PATCH 6.17 209/563] i3c: fix big-endian FIFO transfers Date: Mon, 13 Oct 2025 16:41:10 +0200 Message-ID: <20251013144418.857494703@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251013144411.274874080@linuxfoundation.org> References: <20251013144411.274874080@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnd Bergmann [ Upstream commit d6ddd9beb1a5c32acb9b80f5c2cd8b17f41371d1 ] 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. As data is copied between a FIFO and a memory buffer, the writesl()/readsl() loops are typically based on __raw_readl()/ __raw_writel(), resulting in the order of bytes in the FIFO to match the order in the buffer, regardless of the CPU endianess. 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_writel_fifo()") Cc: Manikanta Guntupalli Signed-off-by: Arnd Bergmann Reviewed-by: Jorge Marques Link: https://lore.kernel.org/r/20250924201837.3691486-1-arnd@kernel.org Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin --- drivers/i3c/internals.h | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/i3c/internals.h b/drivers/i3c/internals.h index 0d857cc68cc5d..79ceaa5f5afd6 100644 --- a/drivers/i3c/internals.h +++ b/drivers/i3c/internals.h @@ -38,7 +38,11 @@ static inline void i3c_writel_fifo(void __iomem *addr, const void *buf, u32 tmp = 0; memcpy(&tmp, buf + (nbytes & ~3), nbytes & 3); - writel(tmp, addr); + /* + * writesl() instead of writel() to keep FIFO + * byteorder on big-endian targets + */ + writesl(addr, &tmp, 1); } } @@ -55,7 +59,11 @@ static inline void i3c_readl_fifo(const void __iomem *addr, void *buf, if (nbytes & 3) { u32 tmp; - tmp = readl(addr); + /* + * readsl() instead of readl() to keep FIFO + * byteorder on big-endian targets + */ + readsl(addr, &tmp, 1); memcpy(buf + (nbytes & ~3), &tmp, nbytes & 3); } } -- 2.51.0