From mboxrd@z Thu Jan 1 00:00:00 1970 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 C895BC77B75 for ; Mon, 8 May 2023 09:52:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232160AbjEHJwU (ORCPT ); Mon, 8 May 2023 05:52:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49132 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233581AbjEHJwR (ORCPT ); Mon, 8 May 2023 05:52:17 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 283932383F for ; Mon, 8 May 2023 02:52:16 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id ADF35621DF for ; Mon, 8 May 2023 09:52:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BEFCAC433D2; Mon, 8 May 2023 09:52:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1683539535; bh=8CzwNqCKKKnedw56dv1I0GxLmR3opeDahK5Tq1C8qiE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LC+1xfrTt/RmgggVLa4So9xK9iilHtn0WrdNu/BW7yBxavbWFTVBoFWnwOHF7Lplw OzW7TurDYb2tD3Ac0lfYzjGxrVjQMCIKC+Dw2+hpFRdWUeDnOELXlHoqJSaUJEGWf7 eHNdxgDPaEngPRLgd84RZNPipnzt7c0Qdro/qZOc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Andy Shevchenko , =?UTF-8?q?Jan=20Kundr=C3=A1t?= Subject: [PATCH 6.1 053/611] serial: max310x: fix IO data corruption in batched operations Date: Mon, 8 May 2023 11:38:15 +0200 Message-Id: <20230508094423.634344138@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230508094421.513073170@linuxfoundation.org> References: <20230508094421.513073170@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jan Kundrát commit 3f42b142ea1171967e40e10e4b0241c0d6d28d41 upstream. 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 operations") Cc: stable@vger.kernel.org Reviewed-by: Andy Shevchenko Signed-off-by: Jan Kundrát Link: https://lore.kernel.org/r/79db8e82aadb0e174bc82b9996423c3503c8fb37.1680732084.git.jan.kundrat@cesnet.cz Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/max310x.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) --- a/drivers/tty/serial/max310x.c +++ b/drivers/tty/serial/max310x.c @@ -525,6 +525,11 @@ static bool max310x_reg_precious(struct return false; } +static bool max310x_reg_noinc(struct device *dev, unsigned int reg) +{ + return reg == MAX310X_RHR_REG; +} + static int max310x_set_baud(struct uart_port *port, int baud) { unsigned int mode = 0, div = 0, frac = 0, c = 0, F = 0; @@ -651,14 +656,14 @@ static void max310x_batch_write(struct u { struct max310x_one *one = to_max310x_port(port); - regmap_raw_write(one->regmap, MAX310X_THR_REG, txbuf, len); + regmap_noinc_write(one->regmap, MAX310X_THR_REG, txbuf, len); } static void max310x_batch_read(struct uart_port *port, u8 *rxbuf, unsigned int len) { struct max310x_one *one = to_max310x_port(port); - regmap_raw_read(one->regmap, MAX310X_RHR_REG, rxbuf, len); + regmap_noinc_read(one->regmap, MAX310X_RHR_REG, rxbuf, len); } static void max310x_handle_rx(struct uart_port *port, unsigned int rxlen) @@ -1472,6 +1477,10 @@ static struct regmap_config regcfg = { .writeable_reg = max310x_reg_writeable, .volatile_reg = max310x_reg_volatile, .precious_reg = max310x_reg_precious, + .writeable_noinc_reg = max310x_reg_noinc, + .readable_noinc_reg = max310x_reg_noinc, + .max_raw_read = MAX310X_FIFO_SIZE, + .max_raw_write = MAX310X_FIFO_SIZE, }; #ifdef CONFIG_SPI_MASTER @@ -1557,6 +1566,10 @@ static struct regmap_config regcfg_i2c = .volatile_reg = max310x_reg_volatile, .precious_reg = max310x_reg_precious, .max_register = MAX310X_I2C_REVID_EXTREG, + .writeable_noinc_reg = max310x_reg_noinc, + .readable_noinc_reg = max310x_reg_noinc, + .max_raw_read = MAX310X_FIFO_SIZE, + .max_raw_write = MAX310X_FIFO_SIZE, }; static const struct max310x_if_cfg max310x_i2c_if_cfg = {