[PATCH 4.4 093/113] dmaengine: usb-dmac: check CHCR.DE bit in usb_dmac_isr_channel()

Greg Kroah-Hartman
2016-09-05T17:11:00Z

From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>

commit 626d2f07de89bf6be3d7301524d0ab3375b81b9c upstream.

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)
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/dma/sh/usb-dmac.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)

--- 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(
{
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);