From patchwork Fri Feb 9 13:55:51 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Th=C3=A9o_Lebrun?= X-Patchwork-Id: 13551246 Received: from relay8-d.mail.gandi.net (relay8-d.mail.gandi.net [217.70.183.201]) (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 C561B286AF; Fri, 9 Feb 2024 13:56:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707486976; cv=none; b=oviaPrGKTr92sc4z4+Pxc3/D4HtT5RVvkEmhpuZm/oU24LPbmC/Tnsuiab2VmY9b/7CU6X/awQ4tdDbgK6C3euGqwqfhtn/e2BDyO49CyBdHHFbbVR02fGprV4UL411h6uS4uygc5gly07Jfn1RSxtaTa9GOtcSqmOwI0uCfg8g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707486976; c=relaxed/simple; bh=MJODknsNdPWKKihYzzcpVIfotVeSxNrGrwbmt2FA684=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Y6JwHb3WmsuQbIwmmcD+YIMsboiYxkouMVy7ytm0inFL4e/IlvBbv7aaQ10gCYTE9LwP2gVZ5oKL0WfTwJx0sSzQL1wQANFZvD1zErzGhfpkZ0XqjxUbg5kFQ4IMbH+mCA9xSba931REHO3OOlXEezi/uxXxu/BSE3fsJUv0qas= 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=VOlPNAV+; arc=none smtp.client-ip=217.70.183.201 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="VOlPNAV+" Received: by mail.gandi.net (Postfix) with ESMTPSA id 3393D1BF20A; Fri, 9 Feb 2024 13:56:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1707486965; 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=mHHh5pthlaRvRNGcIbfyZm+1KloZJQv9bQbNMTFQ/6M=; b=VOlPNAV+tLPiurdzfe97v46AUhH37VsDMw1b/jI6cao5J1q0Kp5XtEJtH7jsDKnozdlOg/ DKyakZx3/Y02haNkXr8PaUtg1obtMx81vPp0ZRAb3zbymAod1GTg+fSrAx5gilmbU1vdy2 EWuW14fIZB31iqm31NFrLyIGG0xAgVM5EgrmkYFXYJ4/vNbqvr5aZa0glNeMW6cC63DQPh M3W4gY8wZdQ8mhLVDkRbCvgck34H5fKTyf4eu4iaSzrdk6LAKdk8KlpVekSoHgr42QSQqn V0NKiQWm+uMZbDUFhdcZ8E07HQaSDe7cLVjukk2mR1nTv+aJus4/xIVALJDaIw== From: =?utf-8?q?Th=C3=A9o_Lebrun?= Date: Fri, 09 Feb 2024 14:55:51 +0100 Subject: [PATCH v3 2/4] spi: cadence-qspi: remove system-wide suspend helper calls from runtime PM hooks Precedence: bulk X-Mailing-List: linux-spi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240209-cdns-qspi-pm-fix-v3-2-540ac222f26b@bootlin.com> References: <20240209-cdns-qspi-pm-fix-v3-0-540ac222f26b@bootlin.com> In-Reply-To: <20240209-cdns-qspi-pm-fix-v3-0-540ac222f26b@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 0.12.4 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,