usb: dwc2: Fix DMA cache alignment issues

commit 4a4863bf2e7932e584a3a462d3c6daf891142ddc upstream.

Insert a padding between data and the stored_xfer_buffer pointer to
ensure they are not on the same cache line.

Otherwise, the stored_xfer_buffer gets corrupted for IN URBs on
non-cache-coherent systems. (In my case: Lantiq xRX200 MIPS)

Fixes: 3bc04e28a030 ("usb: dwc2: host: Get aligned DMA in a more supported way")
Fixes: 56406e017a88 ("usb: dwc2: Fix DMA alignment to start at allocated boundary")
Cc: <stable@vger.kernel.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Minas Harutyunyan <hminas@synopsys.com>
Signed-off-by: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index 260010abf9d81cc78564d6ccfe9171f236341508..9221a02e795801f9794f6957b644f47e93db9596 100644 (file)
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -2673,8 +2673,10 @@ static void dwc2_free_dma_aligned_buffer(struct urb *urb)
                return;
 
        /* Restore urb->transfer_buffer from the end of the allocated area */
-       memcpy(&stored_xfer_buffer, urb->transfer_buffer +
-              urb->transfer_buffer_length, sizeof(urb->transfer_buffer));
+       memcpy(&stored_xfer_buffer,
+              PTR_ALIGN(urb->transfer_buffer + urb->transfer_buffer_length,
+                        dma_get_cache_alignment()),
+              sizeof(urb->transfer_buffer));
 
        if (usb_urb_dir_in(urb)) {
                if (usb_pipeisoc(urb->pipe))
@@ -2706,6 +2708,7 @@ static int dwc2_alloc_dma_aligned_buffer(struct urb *urb, gfp_t mem_flags)
         * DMA
         */
        kmalloc_size = urb->transfer_buffer_length +
+               (dma_get_cache_alignment() - 1) +
                sizeof(urb->transfer_buffer);
 
        kmalloc_ptr = kmalloc(kmalloc_size, mem_flags);
@@ -2716,7 +2719,8 @@ static int dwc2_alloc_dma_aligned_buffer(struct urb *urb, gfp_t mem_flags)
         * Position value of original urb->transfer_buffer pointer to the end
         * of allocation for later referencing
         */
-       memcpy(kmalloc_ptr + urb->transfer_buffer_length,
+       memcpy(PTR_ALIGN(kmalloc_ptr + urb->transfer_buffer_length,
+                        dma_get_cache_alignment()),
               &urb->transfer_buffer, sizeof(urb->transfer_buffer));
 
        if (usb_urb_dir_out(urb))