From: Grygorii Strashko <grygorii.strashko@ti.com>
Date: Mon, 12 Dec 2016 19:37:52 +0000 (-0600)
Subject: usb: dwc3: omap: fix race of pm runtime with irq handler in probe
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=12a7f17fac5b370bec87259e4c718faf563ce900;p=linux-beck.git

usb: dwc3: omap: fix race of pm runtime with irq handler in probe

Now races can happen between interrupt handler execution and PM runtime in
error handling code path in probe and in dwc3_omap_remove() which will lead
to system crash:

in probe:
...
 err1:
	pm_runtime_put_sync(dev);
^^ PM runtime can race with IRQ handler when deferred probing happening
   due to extcon
	pm_runtime_disable(dev);

	return ret;

in dwc3_omap_remove:
...
	dwc3_omap_disable_irqs(omap);
^^ IRQs are disabled in HW, but handler may still run
	of_platform_depopulate(omap->dev);
	pm_runtime_put_sync(&pdev->dev);
^^ PM runtime can race with IRQ handler
	pm_runtime_disable(&pdev->dev);

	return 0;

So, OMAP DWC3 IRQ need to be disabled before calling
pm_runtime_put() in probe and in dwc3_omap_remove().

Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
---

diff --git a/drivers/usb/dwc3/dwc3-omap.c b/drivers/usb/dwc3/dwc3-omap.c
index 29e80cc9b634..eb1b9cb3f9d1 100644
--- a/drivers/usb/dwc3/dwc3-omap.c
+++ b/drivers/usb/dwc3/dwc3-omap.c
@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
+#include <linux/irq.h>
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
 #include <linux/platform_data/dwc3-omap.h>
@@ -510,7 +511,7 @@ static int dwc3_omap_probe(struct platform_device *pdev)
 
 	/* check the DMA Status */
 	reg = dwc3_omap_readl(omap->base, USBOTGSS_SYSCONFIG);
-
+	irq_set_status_flags(omap->irq, IRQ_NOAUTOEN);
 	ret = devm_request_threaded_irq(dev, omap->irq, dwc3_omap_interrupt,
 					dwc3_omap_interrupt_thread, IRQF_SHARED,
 					"dwc3-omap", omap);
@@ -531,7 +532,7 @@ static int dwc3_omap_probe(struct platform_device *pdev)
 	}
 
 	dwc3_omap_enable_irqs(omap);
-
+	enable_irq(omap->irq);
 	return 0;
 
 err2:
@@ -552,6 +553,7 @@ static int dwc3_omap_remove(struct platform_device *pdev)
 	extcon_unregister_notifier(omap->edev, EXTCON_USB, &omap->vbus_nb);
 	extcon_unregister_notifier(omap->edev, EXTCON_USB_HOST, &omap->id_nb);
 	dwc3_omap_disable_irqs(omap);
+	disable_irq(omap->irq);
 	of_platform_depopulate(omap->dev);
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);