From patchwork Thu May 18 13:04:25 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Gerhold X-Patchwork-Id: 13246766 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 8244EC77B7A for ; Thu, 18 May 2023 13:08:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230334AbjERNIN (ORCPT ); Thu, 18 May 2023 09:08:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230305AbjERNIM (ORCPT ); Thu, 18 May 2023 09:08:12 -0400 X-Greylist: delayed 184 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Thu, 18 May 2023 06:07:56 PDT Received: from mo4-p01-ob.smtp.rzone.de (mo4-p01-ob.smtp.rzone.de [81.169.146.164]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0F32F1726; Thu, 18 May 2023 06:07:55 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1684415090; cv=none; d=strato.com; s=strato-dkim-0002; b=jHp5siR+mpF442a5tGnVIsTWCOu67V55rUPcoVou53WJKCWN+qTAmII+Pu7TU8ex/D ySc9MtPECNPRnckq8ffAVuhWY3mWc/KQ02u7XxRUW17+KlUrEjaSL9ImXRvFPzRRWKol T71KZYiJsYr4gC96Z2zjELQQK+JhoCs81WVtBkXj/p34f4eRtWIrU2t580mxujVcEXJT G1ygOstO9LGws1Qvj3qMkD91qtCp2gBluqD0pMam7Bov9bdNLV95awDdWfV8in14ble1 n1unqDIZPTjwKjQ5sA8XcuejNLKxgoPWfLwj0xa8ta5lOfB0E+wELt4DPjZicgOir1J5 vQhg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; t=1684415090; s=strato-dkim-0002; d=strato.com; h=Cc:To:Message-Id:Subject:Date:From:Cc:Date:From:Subject:Sender; bh=1A4pWdRSyRquDJYOJ8/0StLwGPzYcPJ+8wTjCsISdD8=; b=mqzczOcU5K6zxym1zhKJ27g9oD2QhWKdq3EdsIrVgkimBlyZBrFfQXOljU/+/RCH25 8fyIEDniNEt0KIkzKIHH2E+oULCE7lVxi86Xxji3q9xD1vzBZSLCA0ZnHQtAuPRy6RA5 mp/YBNaxbQNQojX/Vuj101TvU2lWPkOjNqEzIRfoWMM8pMiMKCWtYNHOyA4SA+AHGQ4Q 7aROCLu6uGh/wsTMaMQfrZEPLIwgMdMKzOvzgnahRlVn/TR6RG5HK5fcSfHIDd6EA4lG 4qUQWq23DngjEYt1c/AyhBmYspLWrfwjO5X2lGtoL9MArqlgRUtl9JEufiIUI4O0eCJ9 oEgw== ARC-Authentication-Results: i=1; strato.com; arc=none; dkim=none X-RZG-CLASS-ID: mo01 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1684415090; s=strato-dkim-0002; d=gerhold.net; h=Cc:To:Message-Id:Subject:Date:From:Cc:Date:From:Subject:Sender; bh=1A4pWdRSyRquDJYOJ8/0StLwGPzYcPJ+8wTjCsISdD8=; b=bMshw8duaax9aITLuq2vz4VCipAk+DcXI85nhKezpsY8LVVBtlG6dTZcX4xYDv2/77 iEfY6hurG0RjWXSq97qNkyCEQa3wy8DVpAjuQIZ5+Q29Vauu12m5AUVJo5YUBubesoZQ F/UB6WkPa9O3IShE+ABpnRS/tBWGNXteaXAwcjzTnnpz/RlVKxKnn0/6LgfwgpM7t6qY +3YFpntevYSlXTlPUm/UBYS6X/kPC3Enjuzehl+8Xg5SVDfM4nKHl4DzPZQlGT5ra1uS yGSlF8zgAfGd08Q2KSHPcJH4UaqvDx4KPt2cgkHe7+TccuiAUPOw5Rfck4vjy/IJjqzW JkFA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; t=1684415090; s=strato-dkim-0003; d=gerhold.net; h=Cc:To:Message-Id:Subject:Date:From:Cc:Date:From:Subject:Sender; bh=1A4pWdRSyRquDJYOJ8/0StLwGPzYcPJ+8wTjCsISdD8=; b=yR1zUV+6SNnB74h2L/cWgn5U5zo14cpDUHP5THYm7utMH3ChNq/dMEz/+zkdzZFBlv uAgFYXaxT8wdiC72HDDQ== X-RZG-AUTH: ":P3gBZUipdd93FF5ZZvYFPugejmSTVR2nRPhVOQjVd4CteZ/7jYgS+mLFY+H0JAn8u4p1/zY=" Received: from [192.168.244.3] by smtp.strato.de (RZmta 49.4.0 DYNA|AUTH) with ESMTPSA id j6420az4ID4oCWf (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Thu, 18 May 2023 15:04:50 +0200 (CEST) From: Stephan Gerhold Date: Thu, 18 May 2023 15:04:25 +0200 Subject: [PATCH] spi: qup: Request DMA before enabling clocks MIME-Version: 1.0 Message-Id: <20230518-spi-qup-clk-defer-v1-1-f49fc9ca4e02@gerhold.net> X-B4-Tracking: v=1; b=H4sIAFgiZmQC/x2N0QrCMAwAf2Xk2UC7MhF/RXzo2tQFS60JG8LYv xv2eAfH7aAkTAr3YQehjZU/zcBfBkhLbC9CzsYwujG4yd9QO+N37ZjqGzMVEswlhkRXHxwFsG6 OSjhLbGmxsq21muxChX/n6PE8jj/UF+p5eAAAAA== To: Mark Brown Cc: Bjorn Andersson , Andy Gross , Konrad Dybcio , Stanimir Varbanov , linux-arm-msm@vger.kernel.org, linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, Stephan Gerhold X-Mailer: b4 0.12.2 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org 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 --- drivers/spi/spi-qup.c | 37 ++++++++++++++++++------------------- 1 file changed, 18 insertions(+), 19 deletions(-) --- base-commit: 5e41763e97db00125dec847e54a1827436d34cd3 change-id: 20230518-spi-qup-clk-defer-dfa3ce6130e3 Best regards, diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c index 944ef6b42bce..00e5e88e72c4 100644 --- a/drivers/spi/spi-qup.c +++ b/drivers/spi/spi-qup.c @@ -1028,23 +1028,8 @@ 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; }