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>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
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 6202102..a516af2 100644
--- a/drivers/usb/host/ehci-tegra.c
+++ b/drivers/usb/host/ehci-tegra.c
@@ -23,6 +23,8 @@
#include <linux/usb/otg.h>
#include <mach/usb_phy.h>
+#define TEGRA_USB_DMA_ALIGN 32
+
struct tegra_ehci_hcd {
struct ehci_hcd *ehci;
struct tegra_usb_phy *phy;
@@ -383,6 +385,92 @@ 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",
@@ -398,6 +486,8 @@ 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,
--
1.7.4.1
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
