From: Krzysztof Kozlowski <k.kozlowski@samsung.com>
To: Russell King <linux@arm.linux.org.uk>,
Dan Williams <dan.j.williams@intel.com>,
Vinod Koul <vinod.koul@intel.com>,
linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org,
Ulf Hansson <ulf.hansson@linaro.org>,
Grant Likely <grant.likely@linaro.org>,
Lars-Peter Clausen <lars@metafoo.de>,
Michal Simek <michal.simek@xilinx.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
Randy Dunlap <rdunlap@infradead.org>,
Alan Stern <stern@rowland.harvard.edu>,
linux-doc@vger.kernel.org, linux-pm@vger.kernel.org
Cc: Kyungmin Park <kyungmin.park@samsung.com>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
Krzysztof Kozlowski <k.kozlowski@samsung.com>
Subject: [PATCH v5 3/4] amba: Don't unprepare the clocks if device driver wants IRQ safe runtime PM
Date: Tue, 16 Sep 2014 14:59:19 +0200 [thread overview]
Message-ID: <1410872360-27029-4-git-send-email-k.kozlowski@samsung.com> (raw)
In-Reply-To: <1410872360-27029-1-git-send-email-k.kozlowski@samsung.com>
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 <k.kozlowski@samsung.com>
---
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
next prev parent reply other threads:[~2014-09-16 13:01 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-16 12:59 [PATCH v5 0/4] amba/dma: pl330: add Power Management support Krzysztof Kozlowski
2014-09-16 12:59 ` [PATCH v5 1/4] PM / Runtime: Add getter for quering the IRQ safe option Krzysztof Kozlowski
2014-09-16 18:27 ` Ulf Hansson
2014-09-16 12:59 ` [PATCH v5 2/4] amba: Add helper macros for (un)preparing AMBA clock Krzysztof Kozlowski
2014-09-16 12:59 ` Krzysztof Kozlowski [this message]
2014-09-16 18:25 ` [PATCH v5 3/4] amba: Don't unprepare the clocks if device driver wants IRQ safe runtime PM Ulf Hansson
2014-09-16 19:52 ` Russell King - ARM Linux
2014-09-17 17:59 ` Ulf Hansson
2014-09-16 12:59 ` [PATCH v5 4/4] dma: pl330: add Power Management support Krzysztof Kozlowski
2014-09-16 16:18 ` [PATCH v5 0/4] amba/dma: " Russell King - ARM Linux
2014-09-16 16:28 ` Krzysztof Kozlowski
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