From nobody Fri Dec 19 20:04:21 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 2583764CF7; Wed, 13 Mar 2024 16:43:50 +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=1710348230; cv=none; b=dEnwYEUX2aF53olW4s9D2UdUtzczeDZOK+Ki4+K+wCXbBYLsPNpHdQTAfa+GcWxYNfGUWc0ytijjW5sfyMcQVwsjBDK3vNnDSJHO2b60AcAIVZyoeho2NAjk5kVvRKsUeuRWJuC7I1hHLLCng/DSscWE08hq+vl5ZnfSJXDtG6k= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710348230; c=relaxed/simple; bh=j+1HcfbnqtQLFCt/+wgkCnxHewRTQth12vYb5SjsB1Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=sZSNn+VcahcspCtkqXaWSsmUs12Vx4lLplZQAWB+NUPBqMCx/LCWPUFwJq+i78nvNtXrUC/nDGzofUnYDEABj8yXinmw/QnHlrhQOYza7TtYreXzTremphqwsKpeQFWVIjG/ArTmKmMwHbCFtCori3gj2/Tc+dl66WNu1YA+GrI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=T3dVMaiR; 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="T3dVMaiR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 29CE8C433F1; Wed, 13 Mar 2024 16:43:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1710348230; bh=j+1HcfbnqtQLFCt/+wgkCnxHewRTQth12vYb5SjsB1Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=T3dVMaiR6FfSP+z9i0LUXLirzqx3QiyCNF5pkMH4w8sMwy1uSWY/ixL4DqKLMdjya iyaiNZOTKikqaSq2BVl5B43OzooTsbJeL+iFfRNWtP9QnKuuJtA3XKV6jdJtiFMeRf zGc4oZJS61o4QfAzUAAGpU5JYuVxfIdTfeQAGB/VZ83cpRuLfbJOi5jy8Yl5RHLl6q e0lvG5+o8Mr5/a/yfZHiDZPn0oHmtSlGAxDB56t896kaVHmBL2V11JqQyWV5NU9ItF LsWSstvsp1BuSjpPg7OOjiOpahhfIu076tVAQh0uu3PEZ79sfOkTfYAAiKuCTIcblb /KC417gWb7v8g== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: =?UTF-8?q?Jan=20Kundr=C3=A1t?= , Andy Shevchenko , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 5.15 75/76] serial: max310x: fix IO data corruption in batched operations Date: Wed, 13 Mar 2024 12:42:22 -0400 Message-ID: <20240313164223.615640-76-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240313164223.615640-1-sashal@kernel.org> References: <20240313164223.615640-1-sashal@kernel.org> 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" X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.15.152-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-5.15.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 5.15.152-rc1 X-KernelTest-Deadline: 2024-03-15T16:42+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: quoted-printable From: Jan Kundr=C3=A1t [ Upstream commit 3f42b142ea1171967e40e10e4b0241c0d6d28d41 ] After upgrading from 5.16 to 6.1, our board with a MAX14830 started producing lots of garbage data over UART. Bisection pointed out commit 285e76fc049c as the culprit. That patch tried to replace hand-written code which I added in 2b4bac48c1084 ("serial: max310x: Use batched reads when reasonably safe") with the generic regmap infrastructure for batched operations. Unfortunately, the `regmap_raw_read` and `regmap_raw_write` which were used are actually functions which perform IO over *multiple* registers. That's not what is needed for accessing these Tx/Rx FIFOs; the appropriate functions are the `_noinc_` versions, not the `_raw_` ones. Fix this regression by using `regmap_noinc_read()` and `regmap_noinc_write()` along with the necessary `regmap_config` setup; with this patch in place, our board communicates happily again. Since our board uses SPI for talking to this chip, the I2C part is completely untested. Fixes: 285e76fc049c ("serial: max310x: use regmap methods for SPI batch ope= rations") Cc: stable@vger.kernel.org Reviewed-by: Andy Shevchenko Signed-off-by: Jan Kundr=C3=A1t Link: https://lore.kernel.org/r/79db8e82aadb0e174bc82b9996423c3503c8fb37.16= 80732084.git.jan.kundrat@cesnet.cz Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/max310x.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c index 4299211183a74..c122e7e90fc89 100644 --- a/drivers/tty/serial/max310x.c +++ b/drivers/tty/serial/max310x.c @@ -511,6 +511,11 @@ static bool max310x_reg_precious(struct device *dev, u= nsigned int reg) return false; } =20 +static bool max310x_reg_noinc(struct device *dev, unsigned int reg) +{ + return reg =3D=3D MAX310X_RHR_REG; +} + static int max310x_set_baud(struct uart_port *port, int baud) { unsigned int mode =3D 0, div =3D 0, frac =3D 0, c =3D 0, F =3D 0; @@ -645,14 +650,14 @@ static void max310x_batch_write(struct uart_port *por= t, u8 *txbuf, unsigned int { struct max310x_one *one =3D to_max310x_port(port); =20 - regmap_raw_write(one->regmap, MAX310X_THR_REG, txbuf, len); + regmap_noinc_write(one->regmap, MAX310X_THR_REG, txbuf, len); } =20 static void max310x_batch_read(struct uart_port *port, u8 *rxbuf, unsigned= int len) { struct max310x_one *one =3D to_max310x_port(port); =20 - regmap_raw_read(one->regmap, MAX310X_RHR_REG, rxbuf, len); + regmap_noinc_read(one->regmap, MAX310X_RHR_REG, rxbuf, len); } =20 static void max310x_handle_rx(struct uart_port *port, unsigned int rxlen) @@ -1481,6 +1486,10 @@ static struct regmap_config regcfg =3D { .writeable_reg =3D max310x_reg_writeable, .volatile_reg =3D max310x_reg_volatile, .precious_reg =3D max310x_reg_precious, + .writeable_noinc_reg =3D max310x_reg_noinc, + .readable_noinc_reg =3D max310x_reg_noinc, + .max_raw_read =3D MAX310X_FIFO_SIZE, + .max_raw_write =3D MAX310X_FIFO_SIZE, }; =20 #ifdef CONFIG_SPI_MASTER --=20 2.43.0