dmaengine: usb-dmac: check CHCR.DE bit in usb_dmac_isr_channel()

The USB-DMAC's interruption happens even if the CHCR.DE is not set to 1
because CHCR.NULLE is set to 1. So, this driver should call
usb_dmac_isr_transfer_end() if the DE bit is set to 1 only. Otherwise,
the desc is possible to be NULL in the usb_dmac_isr_transfer_end().

Fixes: 0c1c8ff32fa2 ("dmaengine: usb-dmac: Add Renesas USB DMA Controller (USB-DMAC) driver)
Cc: <stable@vger.kernel.org> # v4.1+
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 11 insertions, 8 deletions

diff --git a/drivers/dma/sh/usb-dmac.c b/drivers/dma/sh/usb-dmac.c
index 749f1bd5d65d..06ecdc38cee0 100644
--- a/drivers/dma/sh/usb-dmac.c
+++ b/drivers/dma/sh/usb-dmac.c
@@ -600,27 +600,30 @@ static irqreturn_t usb_dmac_isr_channel(int irq, void *dev)
 {
         struct usb_dmac_chan *chan = dev;
         irqreturn_t ret = IRQ_NONE;
-        u32 mask = USB_DMACHCR_TE;
-        u32 check_bits = USB_DMACHCR_TE | USB_DMACHCR_SP;
+        u32 mask = 0;
         u32 chcr;
+        bool xfer_end = false;
 
         spin_lock(&chan->vc.lock);
 
         chcr = usb_dmac_chan_read(chan, USB_DMACHCR);
-        if (chcr & check_bits)
-                mask |= USB_DMACHCR_DE | check_bits;
+        if (chcr & (USB_DMACHCR_TE | USB_DMACHCR_SP)) {
+                mask |= USB_DMACHCR_DE | USB_DMACHCR_TE | USB_DMACHCR_SP;
+                if (chcr & USB_DMACHCR_DE)
+                        xfer_end = true;
+                ret |= IRQ_HANDLED;
+        }
         if (chcr & USB_DMACHCR_NULL) {
                 /* An interruption of TE will happen after we set FTE */
                 mask |= USB_DMACHCR_NULL;
                 chcr |= USB_DMACHCR_FTE;
                 ret |= IRQ_HANDLED;
         }
-        usb_dmac_chan_write(chan, USB_DMACHCR, chcr & ~mask);
+        if (mask)
+                usb_dmac_chan_write(chan, USB_DMACHCR, chcr & ~mask);
 
-        if (chcr & check_bits) {
+        if (xfer_end)
                 usb_dmac_isr_transfer_end(chan);
-                ret |= IRQ_HANDLED;
-        }
 
         spin_unlock(&chan->vc.lock);