From: Robert Morell <rmorell@xxxxxxxxxx> The Tegra2 USB controller doesn't properly deal with misaligned DMA buffers, causing corruption. This is especially prevalent with USB network adapters, where skbuff alignment is often in the middle of a 4-byte dword. To avoid this, allocate a temporary buffer for the DMA if the provided buffer isn't sufficiently aligned. Signed-off-by: Robert Morell <rmorell@xxxxxxxxxx> Signed-off-by: Benoit Goby <benoit@xxxxxxxxxxx> --- drivers/usb/host/ehci-tegra.c | 90 +++++++++++++++++++++++++++++++++++++++++ 1 files changed, 90 insertions(+), 0 deletions(-) diff --git a/drivers/usb/host/ehci-tegra.c b/drivers/usb/host/ehci-tegra.c index 5c5ee91..c64d629 100644 --- a/drivers/usb/host/ehci-tegra.c +++ b/drivers/usb/host/ehci-tegra.c @@ -28,6 +28,8 @@ #define TEGRA_USB_PORTSC1_PTC(x) (((x) & 0xf) << 16) +#define TEGRA_USB_DMA_ALIGN 32 + struct tegra_ehci_hcd { struct ehci_hcd *ehci; struct tegra_usb_phy *phy; @@ -388,6 +390,92 @@ static int tegra_ehci_bus_resume(struct usb_hcd *hcd) } #endif +struct temp_buffer { + void *kmalloc_ptr; + void *old_xfer_buffer; + u8 data[0]; +}; + +static void free_temp_buffer(struct urb *urb) +{ + enum dma_data_direction dir; + struct temp_buffer *temp; + + if (!(urb->transfer_flags & URB_ALIGNED_TEMP_BUFFER)) + return; + + dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE; + + temp = container_of(urb->transfer_buffer, struct temp_buffer, + data); + + if (dir == DMA_FROM_DEVICE) + memcpy(temp->old_xfer_buffer, temp->data, + urb->transfer_buffer_length); + urb->transfer_buffer = temp->old_xfer_buffer; + kfree(temp->kmalloc_ptr); + + urb->transfer_flags &= ~URB_ALIGNED_TEMP_BUFFER; +} + +static int alloc_temp_buffer(struct urb *urb, gfp_t mem_flags) +{ + enum dma_data_direction dir; + struct temp_buffer *temp, *kmalloc_ptr; + size_t kmalloc_size; + + if (urb->num_sgs || urb->sg || + urb->transfer_buffer_length == 0 || + !((uintptr_t)urb->transfer_buffer & (TEGRA_USB_DMA_ALIGN - 1))) + return 0; + + dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE; + + /* Allocate a buffer with enough padding for alignment */ + kmalloc_size = urb->transfer_buffer_length + + sizeof(struct temp_buffer) + TEGRA_USB_DMA_ALIGN - 1; + + kmalloc_ptr = kmalloc(kmalloc_size, mem_flags); + if (!kmalloc_ptr) + return -ENOMEM; + + /* Position our struct temp_buffer such that data is aligned */ + temp = PTR_ALIGN(kmalloc_ptr + 1, TEGRA_USB_DMA_ALIGN) - 1; + + temp->kmalloc_ptr = kmalloc_ptr; + temp->old_xfer_buffer = urb->transfer_buffer; + if (dir == DMA_TO_DEVICE) + memcpy(temp->data, urb->transfer_buffer, + urb->transfer_buffer_length); + urb->transfer_buffer = temp->data; + + urb->transfer_flags |= URB_ALIGNED_TEMP_BUFFER; + + return 0; +} + +static int tegra_ehci_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb, + gfp_t mem_flags) +{ + int ret; + + ret = alloc_temp_buffer(urb, mem_flags); + if (ret) + return ret; + + ret = usb_hcd_map_urb_for_dma(hcd, urb, mem_flags); + if (ret) + free_temp_buffer(urb); + + return ret; +} + +static void tegra_ehci_unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb) +{ + usb_hcd_unmap_urb_for_dma(hcd, urb); + free_temp_buffer(urb); +} + static const struct hc_driver tegra_ehci_hc_driver = { .description = hcd_name, .product_desc = "Tegra EHCI Host Controller", @@ -403,6 +491,8 @@ static const struct hc_driver tegra_ehci_hc_driver = { .shutdown = tegra_ehci_shutdown, .urb_enqueue = ehci_urb_enqueue, .urb_dequeue = ehci_urb_dequeue, + .map_urb_for_dma = tegra_ehci_map_urb_for_dma, + .unmap_urb_for_dma = tegra_ehci_unmap_urb_for_dma, .endpoint_disable = ehci_endpoint_disable, .endpoint_reset = ehci_endpoint_reset, .get_frame_number = ehci_get_frame, -- 1.7.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html