usb: musb: add a work_struct to recover from babble errors

Handle BABBLE interrupt error conditions from a work struct handler.
This indirection is necessary as we can't be certain that the phy
functions don't sleep.

Platform layer implementation may pass a babble error down to the core
in order to handle it.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

2 files changed, 36 insertions, 0 deletions

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index 07576907e2c6..61da471b7aed 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -848,6 +848,10 @@ b_host:
                 }
         }
 
+        /* handle babble condition */
+        if (int_usb & MUSB_INTR_BABBLE)
+                schedule_work(&musb->recover_work);
+
 #if 0
 /* REVISIT ... this would be for multiplexing periodic endpoints, or
  * supporting transfer phasing to prevent exceeding ISO bandwidth
@@ -1746,6 +1750,34 @@ static void musb_irq_work(struct work_struct *data)
         }
 }
 
+/* Recover from babble interrupt conditions */
+static void musb_recover_work(struct work_struct *data)
+{
+        struct musb *musb = container_of(data, struct musb, recover_work);
+        int status;
+
+        musb_platform_reset(musb);
+
+        usb_phy_vbus_off(musb->xceiv);
+        udelay(100);
+
+        usb_phy_vbus_on(musb->xceiv);
+        udelay(100);
+
+        /*
+         * When a babble condition occurs, the musb controller removes the
+         * session bit and the endpoint config is lost.
+         */
+        if (musb->dyn_fifo)
+                status = ep_config_from_table(musb);
+        else
+                status = ep_config_from_hw(musb);
+
+        /* start the session again */
+        if (status == 0)
+                musb_start(musb);
+}
+
 /* --------------------------------------------------------------------------
  * Init support
  */
@@ -1913,6 +1945,7 @@ musb_init_controller(struct device *dev, int nIrq, void __iomem *ctrl)
 
         /* Init IRQ workqueue before request_irq */
         INIT_WORK(&musb->irq_work, musb_irq_work);
+        INIT_WORK(&musb->recover_work, musb_recover_work);
         INIT_DELAYED_WORK(&musb->deassert_reset_work, musb_deassert_reset);
         INIT_DELAYED_WORK(&musb->finish_resume_work, musb_host_finish_resume);
 
@@ -2008,6 +2041,7 @@ fail4:
 
 fail3:
         cancel_work_sync(&musb->irq_work);
+        cancel_work_sync(&musb->recover_work);
         cancel_delayed_work_sync(&musb->finish_resume_work);
         cancel_delayed_work_sync(&musb->deassert_reset_work);
         if (musb->dma_controller)
@@ -2073,6 +2107,7 @@ static int musb_remove(struct platform_device *pdev)
                 dma_controller_destroy(musb->dma_controller);
 
         cancel_work_sync(&musb->irq_work);
+        cancel_work_sync(&musb->recover_work);
         cancel_delayed_work_sync(&musb->finish_resume_work);
         cancel_delayed_work_sync(&musb->deassert_reset_work);
         musb_free(musb);
diff --git a/drivers/usb/musb/musb_core.h b/drivers/usb/musb/musb_core.h
index 5514e4c82932..47e88747e3a7 100644
--- a/drivers/usb/musb/musb_core.h
+++ b/drivers/usb/musb/musb_core.h
@@ -297,6 +297,7 @@ struct musb {
 
         irqreturn_t             (*isr)(int, void *);
         struct work_struct      irq_work;
+        struct work_struct      recover_work;
         struct delayed_work     deassert_reset_work;
         struct delayed_work     finish_resume_work;
         u16                     hwvers;