usb: dwc3: pci: Runtime resume child device from wq

Driver currently resumes and increments pm usage_count
of its child device (dwc3 main) from its runtime_resume
handler. This requires dwc3 runtime_resume to perform
pm_runtime_put to decrement the pm usage_count. However
runtime_put from dwc3 happens for non pci drivers
(e.g. dwc3-if-simple.c) as well which results in dwc3
pm usage_count becoming negative after couple of
runtime suspend resume iterations. Fix this by
performing runtime_get/put from dwc3-pci driver only
using workqueue.

Signed-off-by: Manu Gautam <mgautam@codeaurora.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index f75613f..23bb192 100644 (file)
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1391,7 +1391,6 @@ static int dwc3_runtime_resume(struct device *dev)
        }
 
        pm_runtime_mark_last_busy(dev);
-       pm_runtime_put(dev);
 
        return 0;
 }

diff --git a/drivers/usb/dwc3/dwc3-pci.c b/drivers/usb/dwc3/dwc3-pci.c
index 54343fb..261ee80 100644 (file)
--- a/drivers/usb/dwc3/dwc3-pci.c
+++ b/drivers/usb/dwc3/dwc3-pci.c
@@ -20,6 +20,7 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/pci.h>
+#include <linux/workqueue.h>
 #include <linux/pm_runtime.h>
 #include <linux/platform_device.h>
 #include <linux/gpio/consumer.h>
@@ -61,6 +62,7 @@ struct dwc3_pci {
        guid_t guid;
 
        unsigned int has_dsm_for_pm:1;
+       struct work_struct wakeup_work;
 };
 
 static const struct acpi_gpio_params reset_gpios = { 0, 0, false };
@@ -174,6 +176,22 @@ static int dwc3_pci_quirks(struct dwc3_pci *dwc)
        return 0;
 }
 
+#ifdef CONFIG_PM
+static void dwc3_pci_resume_work(struct work_struct *work)
+{
+       struct dwc3_pci *dwc = container_of(work, struct dwc3_pci, wakeup_work);
+       struct platform_device *dwc3 = dwc->dwc3;
+       int ret;
+
+       ret = pm_runtime_get_sync(&dwc3->dev);
+       if (ret)
+               return;
+
+       pm_runtime_mark_last_busy(&dwc3->dev);
+       pm_runtime_put_sync_autosuspend(&dwc3->dev);
+}
+#endif
+
 static int dwc3_pci_probe(struct pci_dev *pci,
                const struct pci_device_id *id)
 {
@@ -232,6 +250,9 @@ static int dwc3_pci_probe(struct pci_dev *pci,
        device_init_wakeup(dev, true);
        pci_set_drvdata(pci, dwc);
        pm_runtime_put(dev);
+#ifdef CONFIG_PM
+       INIT_WORK(&dwc->wakeup_work, dwc3_pci_resume_work);
+#endif
 
        return 0;
 err:
@@ -243,6 +264,9 @@ static void dwc3_pci_remove(struct pci_dev *pci)
 {
        struct dwc3_pci         *dwc = pci_get_drvdata(pci);
 
+#ifdef CONFIG_PM
+       cancel_work_sync(&dwc->wakeup_work);
+#endif
        device_init_wakeup(&pci->dev, false);
        pm_runtime_get(&pci->dev);
        platform_device_unregister(dwc->dwc3);
@@ -318,14 +342,15 @@ static int dwc3_pci_runtime_suspend(struct device *dev)
 static int dwc3_pci_runtime_resume(struct device *dev)
 {
        struct dwc3_pci         *dwc = dev_get_drvdata(dev);
-       struct platform_device  *dwc3 = dwc->dwc3;
        int                     ret;
 
        ret = dwc3_pci_dsm(dwc, PCI_INTEL_BXT_STATE_D0);
        if (ret)
                return ret;
 
-       return pm_runtime_get(&dwc3->dev);
+       queue_work(pm_wq, &dwc->wakeup_work);
+
+       return 0;
 }
 #endif /* CONFIG_PM */