DMA-API: usb: ohci-sa1111: add a note about DMA masks

Add a comment to explain why this driver doesn't call any of the DMA
API dma_set_mask() functions.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/usb/host/ohci-sa1111.c b/drivers/usb/host/ohci-sa1111.c
index 17b2a7dad77b..aa9e127bbe71 100644
--- a/drivers/usb/host/ohci-sa1111.c
+++ b/drivers/usb/host/ohci-sa1111.c
@@ -185,6 +185,12 @@ static int ohci_hcd_sa1111_probe(struct sa1111_dev *dev)
         if (usb_disabled())
                 return -ENODEV;
 
+        /*
+         * We don't call dma_set_mask_and_coherent() here because the
+         * DMA mask has already been appropraitely setup by the core
+         * SA-1111 bus code (which includes bug workarounds.)
+         */
+
         hcd = usb_create_hcd(&ohci_sa1111_hc_driver, &dev->dev, "sa1111");
         if (!hcd)
                 return -ENOMEM;