usb: musb: core: add clear_ep_rxintr() to musb_platform_ops

commit 6def85a396ce7796bd9f4561c6ae8138833f7a52 upstream.

During dma teardown for dequque urb, if musb load is high, musb might
generate bogus rx ep interrupt even when the rx fifo is flushed. In such
case any of the follow log messages could happen.

	musb_host_rx 1853: BOGUS RX2 ready, csr 0000, count 0

	musb_host_rx 1936: RX3 dma busy, csr 2020

As mentioned in the current inline comment, clearing ep interrupt in the
teardown path avoids the bogus interrupt.

Clearing ep interrupt is platform dependent, so this patch adds a
platform callback to allow glue driver to clear the ep interrupt.

This bug seems to be existing since the initial driver for musb support,
but I only validated the fix back to v4.1, so only cc stable for v4.1+.

Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/musb/musb_core.h b/drivers/usb/musb/musb_core.h
index 91817d77d59c8ecd226e25fb6ce9e07b5a597d3f..47331dbdde29e2f54de5b61e98807922f942742f 100644 (file)
--- a/drivers/usb/musb/musb_core.h
+++ b/drivers/usb/musb/musb_core.h
@@ -216,6 +216,7 @@ struct musb_platform_ops {
        void    (*pre_root_reset_end)(struct musb *musb);
        void    (*post_root_reset_end)(struct musb *musb);
        int     (*phy_callback)(enum musb_vbus_id_status status);
+       void    (*clear_ep_rxintr)(struct musb *musb, int epnum);
 };
 
 /*
@@ -626,4 +627,10 @@ static inline void musb_platform_post_root_reset_end(struct musb *musb)
                musb->ops->post_root_reset_end(musb);
 }
 
+static inline void musb_platform_clear_ep_rxintr(struct musb *musb, int epnum)
+{
+       if (musb->ops->clear_ep_rxintr)
+               musb->ops->clear_ep_rxintr(musb, epnum);
+}
+
 #endif /* __MUSB_CORE_H__ */

diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index 53bc4ceefe89ad16dcb576fb2fd18c37ad404e23..806451418cfe24fa5974b78554dc71de0614b608 100644 (file)
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -2374,12 +2374,11 @@ static int musb_cleanup_urb(struct urb *urb, struct musb_qh *qh)
        int                     is_in = usb_pipein(urb->pipe);
        int                     status = 0;
        u16                     csr;
+       struct dma_channel      *dma = NULL;
 
        musb_ep_select(regs, hw_end);
 
        if (is_dma_capable()) {
-               struct dma_channel      *dma;
-
                dma = is_in ? ep->rx_channel : ep->tx_channel;
                if (dma) {
                        status = ep->musb->dma_controller->channel_abort(dma);
@@ -2395,10 +2394,9 @@ static int musb_cleanup_urb(struct urb *urb, struct musb_qh *qh)
                /* giveback saves bulk toggle */
                csr = musb_h_flush_rxfifo(ep, 0);
 
-               /* REVISIT we still get an irq; should likely clear the
-                * endpoint's irq status here to avoid bogus irqs.
-                * clearing that status is platform-specific...
-                */
+               /* clear the endpoint's irq status here to avoid bogus irqs */
+               if (is_dma_capable() && dma)
+                       musb_platform_clear_ep_rxintr(musb, ep->epnum);
        } else if (ep->epnum) {
                musb_h_tx_flush_fifo(ep);
                csr = musb_readw(epio, MUSB_TXCSR);