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 25B20C7EE43 for ; Mon, 12 Jun 2023 10:44:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231419AbjFLKoJ (ORCPT ); Mon, 12 Jun 2023 06:44:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48152 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229451AbjFLKnv (ORCPT ); Mon, 12 Jun 2023 06:43:51 -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 014BADC3D for ; Mon, 12 Jun 2023 03:28:43 -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 8326E61500 for ; Mon, 12 Jun 2023 10:28:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 98804C433EF; Mon, 12 Jun 2023 10:28:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1686565722; bh=vVfu/yhtb8jpTRLd5LKyjm6bBEySkG9iaI9UBTXP9UU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0zmI3XCFnN3H2K2mJmEV7VNsk1Zu/PUAv1wNvOXcfKN4bEfF3AYzCPMIy5DPg9+lS VkbAVSOh76dWPjQy/tZclVVE/N10ZSUftIIt2Vx0oUyGKzcP/NZnMCMGdSZ7RdzuHn xwHFAmk7oIaOfsPhxh/nCiZjjvtOq+7bezPndwtI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Stephan Gerhold , Mark Brown , Sasha Levin Subject: [PATCH 4.14 03/21] spi: qup: Request DMA before enabling clocks Date: Mon, 12 Jun 2023 12:25:58 +0200 Message-ID: <20230612101651.190474682@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230612101651.048240731@linuxfoundation.org> References: <20230612101651.048240731@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: Stephan Gerhold [ Upstream commit 0c331fd1dccfba657129380ee084b95c1cedfbef ] It is usually better to request all necessary resources (clocks, regulators, ...) before starting to make use of them. That way they do not change state in case one of the resources is not available yet and probe deferral (-EPROBE_DEFER) is necessary. This is particularly important for DMA channels and IOMMUs which are not enforced by fw_devlink yet (unless you use fw_devlink.strict=1). spi-qup does this in the wrong order, the clocks are enabled and disabled again when the DMA channels are not available yet. This causes issues in some cases: On most SoCs one of the SPI QUP clocks is shared with the UART controller. When using earlycon UART is actively used during boot but might not have probed yet, usually for the same reason (waiting for the DMA controller). In this case, the brief enable/disable cycle ends up gating the clock and further UART console output will halt the system completely. Avoid this by requesting the DMA channels before changing the clock state. Fixes: 612762e82ae6 ("spi: qup: Add DMA capabilities") Signed-off-by: Stephan Gerhold Link: https://lore.kernel.org/r/20230518-spi-qup-clk-defer-v1-1-f49fc9ca4e02@gerhold.net Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/spi/spi-qup.c | 37 ++++++++++++++++++------------------- 1 file changed, 18 insertions(+), 19 deletions(-) diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c index 1ca678bcb5279..933f9342529a4 100644 --- a/drivers/spi/spi-qup.c +++ b/drivers/spi/spi-qup.c @@ -1003,23 +1003,8 @@ static int spi_qup_probe(struct platform_device *pdev) return -ENXIO; } - ret = clk_prepare_enable(cclk); - if (ret) { - dev_err(dev, "cannot enable core clock\n"); - return ret; - } - - ret = clk_prepare_enable(iclk); - if (ret) { - clk_disable_unprepare(cclk); - dev_err(dev, "cannot enable iface clock\n"); - return ret; - } - master = spi_alloc_master(dev, sizeof(struct spi_qup)); if (!master) { - clk_disable_unprepare(cclk); - clk_disable_unprepare(iclk); dev_err(dev, "cannot allocate master\n"); return -ENOMEM; } @@ -1065,6 +1050,19 @@ static int spi_qup_probe(struct platform_device *pdev) spin_lock_init(&controller->lock); init_completion(&controller->done); + ret = clk_prepare_enable(cclk); + if (ret) { + dev_err(dev, "cannot enable core clock\n"); + goto error_dma; + } + + ret = clk_prepare_enable(iclk); + if (ret) { + clk_disable_unprepare(cclk); + dev_err(dev, "cannot enable iface clock\n"); + goto error_dma; + } + iomode = readl_relaxed(base + QUP_IO_M_MODES); size = QUP_IO_M_OUTPUT_BLOCK_SIZE(iomode); @@ -1094,7 +1092,7 @@ static int spi_qup_probe(struct platform_device *pdev) ret = spi_qup_set_state(controller, QUP_STATE_RESET); if (ret) { dev_err(dev, "cannot set RESET state\n"); - goto error_dma; + goto error_clk; } writel_relaxed(0, base + QUP_OPERATIONAL); @@ -1118,7 +1116,7 @@ static int spi_qup_probe(struct platform_device *pdev) ret = devm_request_irq(dev, irq, spi_qup_qup_irq, IRQF_TRIGGER_HIGH, pdev->name, controller); if (ret) - goto error_dma; + goto error_clk; pm_runtime_set_autosuspend_delay(dev, MSEC_PER_SEC); pm_runtime_use_autosuspend(dev); @@ -1133,11 +1131,12 @@ static int spi_qup_probe(struct platform_device *pdev) disable_pm: pm_runtime_disable(&pdev->dev); +error_clk: + clk_disable_unprepare(cclk); + clk_disable_unprepare(iclk); error_dma: spi_qup_release_dma(master); error: - clk_disable_unprepare(cclk); - clk_disable_unprepare(iclk); spi_master_put(master); return ret; } -- 2.39.2