From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay7-d.mail.gandi.net (relay7-d.mail.gandi.net [217.70.183.200]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ADB343987A; Thu, 22 Feb 2024 10:12:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.200 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708596758; cv=none; b=CPbwKFM/GgQGFsiuOXCPdVpNtiB9SpJTetLd+qdguv5qF1tduXq6C3rYMXUlII2RbNOBNB9BHJ+bnTGNlZBb5T3sjen9KbVdV1FxmLUrXAGcXOzu1PHkAIdnltHFQj9i3bqNKy+D+snMZHVMy/trSRYU/8lyR6FJvxtWMP1toIk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708596758; c=relaxed/simple; bh=U+gzS1ckVJjVA+ftOBxZZr+oCPKKnY2akQ+FTUE4Vlo=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=JimIglmSvNhdVYyTGbFWrp98VTI8397ueBQi9hXVABdFLl8F/mqyqIrRymuhGwtd7urMrXbmw3BxT+bF+lAkVY5rUw86EHautfhaapToPBYZwMnndauHdY+FwJcWV5qtoTFugSo7gzHAA3KRmz8pZGOPddlp2Hllfd1THCNfJa0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=dsw6aMVe; arc=none smtp.client-ip=217.70.183.200 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="dsw6aMVe" Received: by mail.gandi.net (Postfix) with ESMTPSA id 538872000D; Thu, 22 Feb 2024 10:12:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1708596751; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Kr+jGKZ7wa4euSb09lk+qCqBrZfe1hy6OrbVIm5KELU=; b=dsw6aMVe503SzQB89/ddzyuJ08+ZL7xstYhTijpcje0Wv9Zr92DVNUljvFTlOHNMCg0TFY NSDq8XEDWEvjkbsXHhxTXNBHcGwmwLH9CRFP17TfJVWJZ12xX/oyKLs3NwcFgu0Gnvlwpm ft6uzCM7UCQ96ffobAChRCH1vFNm6YyukGTRAZZ/TRnXboUVmFN38QcZ6CWVvVK0FcF+0h fFtlhR14w0ApR5fUA58MefDhqH5oeFxBkGhZ8XAs5VdPLEpYU57EGuwTZiZsft+4mEVvyT ZvsFuIk4OQ4FsvaOWA4Tlu7lQaU38ZKCUbrV8RNoQhFHL5ev2LL6ZuWqvDX7BQ== From: =?utf-8?q?Th=C3=A9o_Lebrun?= Date: Thu, 22 Feb 2024 11:12:30 +0100 Subject: [PATCH v4 2/4] spi: cadence-qspi: remove system-wide suspend helper calls from runtime PM hooks Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Message-Id: <20240222-cdns-qspi-pm-fix-v4-2-6b6af8bcbf59@bootlin.com> References: <20240222-cdns-qspi-pm-fix-v4-0-6b6af8bcbf59@bootlin.com> In-Reply-To: <20240222-cdns-qspi-pm-fix-v4-0-6b6af8bcbf59@bootlin.com> To: Mark Brown , Apurva Nandan , Dhruva Gole Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, Gregory CLEMENT , Vladimir Kondratiev , Thomas Petazzoni , Tawfik Bayouk , =?utf-8?q?Th=C3=A9o_Lebrun?= X-Mailer: b4 0.13.0 X-GND-Sasl: theo.lebrun@bootlin.com The ->runtime_suspend() and ->runtime_resume() callbacks are not expected to call spi_controller_suspend() and spi_controller_resume(). Remove calls to those in the cadence-qspi driver. Those helpers have two roles currently: - They stop/start the queue, including dealing with the kworker. - They toggle the SPI controller SPI_CONTROLLER_SUSPENDED flag. It requires acquiring ctlr->bus_lock_mutex. Step one is irrelevant because cadence-qspi is not queued. Step two however has two implications: - A deadlock occurs, because ->runtime_resume() is called in a context where the lock is already taken (in the ->exec_op() callback, where the usage count is incremented). - It would disallow all operations once the device is auto-suspended. Here is a brief call tree highlighting the mutex deadlock: spi_mem_exec_op() ... spi_mem_access_start() mutex_lock(&ctlr->bus_lock_mutex) cqspi_exec_mem_op() pm_runtime_resume_and_get() cqspi_resume() spi_controller_resume() mutex_lock(&ctlr->bus_lock_mutex) ... spi_mem_access_end() mutex_unlock(&ctlr->bus_lock_mutex) ... Fixes: 0578a6dbfe75 ("spi: spi-cadence-quadspi: add runtime pm support") Signed-off-by: Théo Lebrun --- drivers/spi/spi-cadence-quadspi.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c index d19ba024c80b..809bbbb876ad 100644 --- a/drivers/spi/spi-cadence-quadspi.c +++ b/drivers/spi/spi-cadence-quadspi.c @@ -1930,14 +1930,10 @@ static void cqspi_remove(struct platform_device *pdev) static int cqspi_suspend(struct device *dev) { struct cqspi_st *cqspi = dev_get_drvdata(dev); - int ret; - ret = spi_controller_suspend(cqspi->host); cqspi_controller_enable(cqspi, 0); - clk_disable_unprepare(cqspi->clk); - - return ret; + return 0; } static int cqspi_resume(struct device *dev) @@ -1950,8 +1946,7 @@ static int cqspi_resume(struct device *dev) cqspi->current_cs = -1; cqspi->sclk = 0; - - return spi_controller_resume(cqspi->host); + return 0; } static DEFINE_RUNTIME_DEV_PM_OPS(cqspi_dev_pm_ops, cqspi_suspend, -- 2.43.2