From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753545AbaIVJrF (ORCPT ); Mon, 22 Sep 2014 05:47:05 -0400 Received: from mailout2.w1.samsung.com ([210.118.77.12]:34911 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751678AbaIVJq5 (ORCPT ); Mon, 22 Sep 2014 05:46:57 -0400 X-AuditID: cbfec7f4-b7f156d0000063c7-24-541ff00f03c2 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 v6 3/4] amba: Don't unprepare the clocks if device driver wants IRQ safe runtime PM Date: Mon, 22 Sep 2014 11:46:28 +0200 Message-id: <1411379189-3017-4-git-send-email-k.kozlowski@samsung.com> X-Mailer: git-send-email 1.9.1 In-reply-to: <1411379189-3017-1-git-send-email-k.kozlowski@samsung.com> References: <1411379189-3017-1-git-send-email-k.kozlowski@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrILMWRmVeSWpSXmKPExsVy+t/xq7r8H+RDDF42mFtsnLGe1WL61AuM Fqun/mW1OPBnB6PF6xeGFmeb3rBbLJk8n9Vi1pS9TBYL25awWFzeNYfN4nPvEUaL25d5LdYe uctu8e5lhMXdU0fZLN7emc5iceb0JVaLCb8vsFkcXxtu8bJvP4uDiEdLcw+bx+YVWh6L97xk 8rhzbQ+bx5I3h1g9tlxtZ/GYffcHo0ffllWMHitWf2f3+LxJzmPv598sAdxRXDYpqTmZZalF +nYJXBmH5/xiL1ghWnFoykHWBsaZgl2MnBwSAiYSfXu/skDYYhIX7q1n62Lk4hASWMooMX/H GUYIp49J4v6TRcwgVWwCxhKbly8BqxIROMIi8ezeEzCHWeAoo8T03rdMIFXCAqkSt15vA+rg 4GARUJVoWJ4MEuYVcJP4smo+O8Q6OYmTxyazgticAu4S+5+1gMWFgGqOHJrNNIGRdwEjwypG 0dTS5ILipPRcQ73ixNzi0rx0veT83E2MkGj4soNx8TGrQ4wCHIxKPLwLmuRDhFgTy4orcw8x SnAwK4nwPn0OFOJNSaysSi3Kjy8qzUktPsTIxMEp1cDo1ddzUPZN/YTVM8wYX4WvjLz4RFky 7eMlCx6+nZHhMef6F2nqaYbd/2eoneO92UJb4snNldsbgj+mP1St0xA4cs/mwYrfG9+HbXu6 lXv9z++5672Wf1Ls/jXrSOG3J0nZyb9nmW7YdFs65/XqP08mlR+/MLPs5K/Kddkubpvvqce2 f1m4Y+sSVSWW4oxEQy3mouJEAFJIypVkAgAA 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 only disable/enable 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 | 29 +++++++++++++++++++++++++---- include/linux/amba/bus.h | 1 + 2 files changed, 26 insertions(+), 4 deletions(-) diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c index 3cf61a127ee5..e8fd5706954f 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 +210,10 @@ static int amba_probe(struct device *dev) pm_runtime_enable(dev); ret = pcdrv->probe(pcdev, id); - if (ret == 0) + if (ret == 0) { + pcdev->irq_safe = pm_runtime_is_irq_safe(dev); 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