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 0C90EC7EE2E for ; Mon, 12 Jun 2023 10:52:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229695AbjFLKw4 (ORCPT ); Mon, 12 Jun 2023 06:52:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55640 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235771AbjFLKwl (ORCPT ); Mon, 12 Jun 2023 06:52:41 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CC2441BC1 for ; Mon, 12 Jun 2023 03:37:01 -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 65EA7612A1 for ; Mon, 12 Jun 2023 10:37:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7B9F9C433EF; Mon, 12 Jun 2023 10:37:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1686566220; bh=2qs5QvqZHdL2ahqf7G6zHKoc8BemV4eshuUutC96v/E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=X58hqZkmkest2tsmgzu0HBjHN7EnD4lKO6w2PXuo8rUdgeMY9G4p31y2BOZUxG+Hf V50pkkbwwkE6zWHHfmKt2Z7Qq+t5sZ5AU/h/JsWMp6dX0VRy+zMAJpgcNDXO1drZ5e yWWRfNvmnRYiUxljIW455bYTyw7zaFv3dAYa82no= 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 5.15 12/91] spi: qup: Request DMA before enabling clocks Date: Mon, 12 Jun 2023 12:26:01 +0200 Message-ID: <20230612101702.596380860@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230612101702.085813286@linuxfoundation.org> References: <20230612101702.085813286@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 8bf58510cca6d..2cc9bb413c108 100644 --- a/drivers/spi/spi-qup.c +++ b/drivers/spi/spi-qup.c @@ -1030,23 +1030,8 @@ 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; } @@ -1092,6 +1077,19 @@ 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); @@ -1121,7 +1119,7 @@ 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); @@ -1145,7 +1143,7 @@ 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); @@ -1160,11 +1158,12 @@ 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