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authorRobert Morell <rmorell@nvidia.com>2011-03-10 01:28:57 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2011-03-11 23:22:12 +0100
commitfbf9865c6d96f4a131092d2018056e86113e5cea (patch)
treeee9c5f63d8709bf50817a730360464031761fa27
parentusb: host: Add EHCI driver for NVIDIA Tegra SoCs (diff)
downloadlinux-fbf9865c6d96f4a131092d2018056e86113e5cea.tar.xz
linux-fbf9865c6d96f4a131092d2018056e86113e5cea.zip
USB: ehci: tegra: Align DMA transfers to 32 bytes
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@nvidia.com> Signed-off-by: Benoit Goby <benoit@android.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/usb/host/ehci-tegra.c90
1 files changed, 90 insertions, 0 deletions
diff --git a/drivers/usb/host/ehci-tegra.c b/drivers/usb/host/ehci-tegra.c
index 6202102a6d75..a516af28c29b 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,