From patchwork Mon May 25 12:25:02 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukas Wunner X-Patchwork-Id: 214539 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0FABC433E0 for ; Mon, 25 May 2020 12:27:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C58B72087D for ; Mon, 25 May 2020 12:27:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390505AbgEYM1b (ORCPT ); Mon, 25 May 2020 08:27:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55472 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390500AbgEYM1b (ORCPT ); Mon, 25 May 2020 08:27:31 -0400 Received: from mailout1.hostsharing.net (mailout1.hostsharing.net [IPv6:2a01:37:1000::53df:5fcc:0]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 25909C061A0E for ; Mon, 25 May 2020 05:27:31 -0700 (PDT) Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "*.hostsharing.net", Issuer "COMODO RSA Domain Validation Secure Server CA" (not verified)) by mailout1.hostsharing.net (Postfix) with ESMTPS id 7F47E10030146; Mon, 25 May 2020 14:27:29 +0200 (CEST) Received: from localhost (unknown [87.130.102.138]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by h08.hostsharing.net (Postfix) with ESMTPSA id 4711B6029C6E; Mon, 25 May 2020 14:27:29 +0200 (CEST) X-Mailbox-Line: From 834c446b1cf3284d2660f1bee1ebe3e737cd02a9 Mon Sep 17 00:00:00 2001 Message-Id: <834c446b1cf3284d2660f1bee1ebe3e737cd02a9.1590408496.git.lukas@wunner.de> In-Reply-To: References: From: Lukas Wunner Date: Mon, 25 May 2020 14:25:02 +0200 Subject: [PATCH 2/3] spi: pxa2xx: Fix controller unregister order To: Mark Brown Cc: Andy Shevchenko , Jarkko Nikula , linux-spi@vger.kernel.org, Tsuchiya Yuto , Daniel Mack , Haojian Zhuang , Robert Jarzmik Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org The PXA2xx SPI driver uses devm_spi_register_controller() on bind. As a consequence, on unbind, __device_release_driver() first invokes pxa2xx_spi_remove() before unregistering the SPI controller via devres_release_all(). This order is incorrect: pxa2xx_spi_remove() disables the chip, rendering the SPI bus inaccessible even though the SPI controller is still registered. When the SPI controller is subsequently unregistered, it unbinds all its slave devices. Because their drivers cannot access the SPI bus, e.g. to quiesce interrupts, the slave devices may be left in an improper state. As a rule, devm_spi_register_controller() must not be used if the ->remove() hook performs teardown steps which shall be performed after unregistering the controller and specifically after unbinding of slaves. Fix by reverting to the non-devm variant of spi_register_controller(). An alternative approach would be to use device-managed functions for all steps in pxa2xx_spi_remove(), e.g. by calling devm_add_action_or_reset() on probe. However that approach would add more LoC to the driver and it wouldn't lend itself as well to backporting to stable. The improper use of devm_spi_register_controller() was introduced in 2013 by commit a807fcd090d6 ("spi: pxa2xx: use devm_spi_register_master()"), but all earlier versions of the driver going back to 2006 were likewise broken because they invoked spi_unregister_master() at the end of pxa2xx_spi_remove(), rather than at the beginning. Fixes: e0c9905e87ac ("[PATCH] SPI: add PXA2xx SSP SPI Driver") Link: https://bugzilla.kernel.org/show_bug.cgi?id=206403#c1 Signed-off-by: Lukas Wunner Cc: stable@vger.kernel.org # v2.6.17+ Cc: Tsuchiya Yuto --- drivers/spi/spi-pxa2xx.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c index 20dcbd35611a..2ecf0d8cd9f7 100644 --- a/drivers/spi/spi-pxa2xx.c +++ b/drivers/spi/spi-pxa2xx.c @@ -1885,7 +1885,7 @@ static int pxa2xx_spi_probe(struct platform_device *pdev) /* Register with the SPI framework */ platform_set_drvdata(pdev, drv_data); - status = devm_spi_register_controller(&pdev->dev, controller); + status = spi_register_controller(controller); if (status != 0) { dev_err(&pdev->dev, "problem registering spi controller\n"); goto out_error_pm_runtime_enabled; @@ -1917,6 +1917,8 @@ static int pxa2xx_spi_remove(struct platform_device *pdev) pm_runtime_get_sync(&pdev->dev); + spi_unregister_controller(drv_data->controller); + /* Disable the SSP at the peripheral and SOC level */ pxa2xx_spi_write(drv_data, SSCR0, 0); clk_disable_unprepare(ssp->clk);