From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753686AbaIPIxQ (ORCPT ); Tue, 16 Sep 2014 04:53:16 -0400 Received: from mailout1.w1.samsung.com ([210.118.77.11]:14444 "EHLO mailout1.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753524AbaIPIwS (ORCPT ); Tue, 16 Sep 2014 04:52:18 -0400 X-AuditID: cbfec7f5-b7f776d000003e54-9b-5417fa3a5b89 From: Krzysztof Kozlowski To: Russell King , Dan Williams , Vinod Koul , linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, Ulf Hansson , Grant Likely , Lars-Peter Clausen , Michal Simek , "Rafael J. Wysocki" , Len Brown , Pavel Machek , Randy Dunlap , Alan Stern , linux-doc@vger.kernel.org, linux-pm@vger.kernel.org Cc: Kyungmin Park , Marek Szyprowski , Bartlomiej Zolnierkiewicz , Krzysztof Kozlowski Subject: [PATCH v4 3/4] amba: Don't unprepare the clocks if device driver wants IRQ safe runtime PM Date: Tue, 16 Sep 2014 10:51:33 +0200 Message-id: <1410857494-15936-4-git-send-email-k.kozlowski@samsung.com> X-Mailer: git-send-email 1.9.1 In-reply-to: <1410857494-15936-1-git-send-email-k.kozlowski@samsung.com> References: <1410857494-15936-1-git-send-email-k.kozlowski@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrILMWRmVeSWpSXmKPExsVy+t/xy7pWv8RDDNbf1rLYOGM9q8X0qRcY LVZP/ctqceDPDkaL1y8MLc42vWG3WDJ5PqvFrCl7mSwWti1hsbi8aw6bxefeI4wWty/zWqw9 cpfd4t3LCIu7p46yWby9M53F4szpS6wWE35fYLM4vjbc4mXffhYHEY+W5h42j80rtDwW73nJ 5HHn2h42jyVvDrF6bLnazuIx++4PRo++LasYPVas/s7u8XmTnMfez79ZArijuGxSUnMyy1KL 9O0SuDIu/j3EWrBDtOJm11b2BsZFgl2MnBwSAiYSS+7/ZYKwxSQu3FvPBmILCSxllLjw0r+L kQvI7mOSWPL0FjNIgk3AWGLz8iVsIAkRgSMsEs/uPQFzmAWOMkpM730LNkpYIFWi/cwZsA4W AVWJ0/9vgo3lFXCXeL7jMxvEOjmJk8cms4LYnAIeEpPmXmeHWO0ucWDvHfYJjLwLGBlWMYqm liYXFCel5xrpFSfmFpfmpesl5+duYoREw9cdjEuPWR1iFOBgVOLhnbFRLESINbGsuDL3EKME B7OSCO+DT+IhQrwpiZVVqUX58UWlOanFhxiZODilGhjVr/H2bhS79vS1pXN70d8Fn//ma3Ls 414X5+7Gf6lG6JH+og/Pm/kznPPed6atufdEIdUhY2GRwJONDy9Hsgn5f+hUDRU5F5+35lb9 yVMefEsirfTXbpT6b8h+RpZFpbTQOONZrXJn3KSyaZLP7YyeKk3jOW+7Z2PkxY1/0tKN7Jr3 bpWt11ViKc5INNRiLipOBAAhQ11dZAIAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The AMBA bus driver defines runtime Power Management functions which disable and unprepare AMBA bus clock. This is problematic for runtime PM because unpreparing a clock might sleep so it is not interrupt safe. However some drivers may want to implement runtime PM functions in interrupt-safe way (see pm_runtime_irq_safe()). In such case the AMBA bus driver should not unprepare/prepare the clock in runtime suspend and resume callbacks. Detect the device driver behavior after calling its probe function and store it. During runtime suspend/resume deal with clocks according to stored value. Signed-off-by: Krzysztof Kozlowski --- drivers/amba/bus.c | 30 ++++++++++++++++++++++++++---- include/linux/amba/bus.h | 1 + 2 files changed, 27 insertions(+), 4 deletions(-) diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c index 3cf61a127ee5..4aee6e61bed2 100644 --- a/drivers/amba/bus.c +++ b/drivers/amba/bus.c @@ -94,8 +94,18 @@ static int amba_pm_runtime_suspend(struct device *dev) struct amba_device *pcdev = to_amba_device(dev); int ret = pm_generic_runtime_suspend(dev); - if (ret == 0 && dev->driver) - clk_disable_unprepare(pcdev->pclk); + if (ret == 0 && dev->driver) { + /* + * Drivers should not change pm_runtime_irq_safe() + * after probe. + */ + WARN_ON(pcdev->irq_safe != pm_runtime_is_irq_safe(dev)); + + if (pcdev->irq_safe) + clk_disable(pcdev->pclk); + else + clk_disable_unprepare(pcdev->pclk); + } return ret; } @@ -106,7 +116,16 @@ static int amba_pm_runtime_resume(struct device *dev) int ret; if (dev->driver) { - ret = clk_prepare_enable(pcdev->pclk); + /* + * Drivers should not change pm_runtime_irq_safe() + * after probe. + */ + WARN_ON(pcdev->irq_safe != pm_runtime_is_irq_safe(dev)); + + if (pcdev->irq_safe) + ret = clk_enable(pcdev->pclk); + else + ret = clk_prepare_enable(pcdev->pclk); /* Failure is probably fatal to the system, but... */ if (ret) return ret; @@ -191,8 +210,11 @@ static int amba_probe(struct device *dev) pm_runtime_enable(dev); ret = pcdrv->probe(pcdev, id); - if (ret == 0) + if (ret == 0) { + if (pm_runtime_is_irq_safe(dev)) + pcdev->irq_safe = 1; break; + } pm_runtime_disable(dev); pm_runtime_set_suspended(dev); diff --git a/include/linux/amba/bus.h b/include/linux/amba/bus.h index ad52027a9cbf..ce101e4497d6 100644 --- a/include/linux/amba/bus.h +++ b/include/linux/amba/bus.h @@ -32,6 +32,7 @@ struct amba_device { struct clk *pclk; unsigned int periphid; unsigned int irq[AMBA_NR_IRQS]; + unsigned int irq_safe:1; }; struct amba_driver { -- 1.9.1