From: Robert Morell <rmorell@nvidia.com>
To: David Brownell <dbrownell@users.sourceforge.net>,
Greg Kroah-Hartman <gregkh@suse.de>,
Benoit Goby <benoit@android.com>,
Alan Stern <stern@rowland.harvard.edu>,
Sarah Sharp <sarah.a.sharp@linux.intel.com>,
Matthew Wilcox <willy@linux.intel.com>,
Ming Lei <tom.leiming@gmail.com>,
Jacob Pan <jacob.jun.pan@intel.com>
Cc: Olof Johansson <olof@lixom.net>,
Erik Gilling <konkers@android.com>,
Colin Cross <ccross@android.com>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-tegra@vger.kernel.org, Robert Morell <rmorell@nvidia.com>
Subject: [PATCH 2/2] USB: ehci: tegra: Align DMA transfers to 32 bytes
Date: Sun, 19 Dec 2010 13:38:18 -0800 [thread overview]
Message-ID: <1292794698-19534-3-git-send-email-rmorell@nvidia.com> (raw)
In-Reply-To: <1292636971-17701-1-git-send-email-rmorell@nvidia.com>
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>
---
drivers/usb/host/ehci-tegra.c | 91 +++++++++++++++++++++++++++++++++++++++++
1 files changed, 91 insertions(+), 0 deletions(-)
diff --git a/drivers/usb/host/ehci-tegra.c b/drivers/usb/host/ehci-tegra.c
index d990c1c..9030fa5 100644
--- a/drivers/usb/host/ehci-tegra.c
+++ b/drivers/usb/host/ehci-tegra.c
@@ -32,6 +32,8 @@
#define TEGRA_USB_USBMODE_HOST (3 << 0)
#define TEGRA_USB_PORTSC1_PTC(x) (((x) & 0xf) << 16)
+#define TEGRA_USB_DMA_ALIGN 32
+
struct tegra_ehci_context {
bool valid;
u32 command;
@@ -457,6 +459,93 @@ 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;
+ void *data;
+
+ 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",
@@ -472,6 +561,8 @@ 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,
--
1.7.2.2
next prev parent reply other threads:[~2010-12-19 21:42 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-17 21:58 [RFC] Align tegra-ehci DMA transfers to 32B Robert Morell
2010-12-17 21:58 ` [PATCH 1/2] USB: Add driver hooks for (un)?map_urb_for_dma Robert Morell
2010-12-17 21:58 ` [PATCH 2/2] USB: ehci: tegra: Align DMA transfers to 32 bytes Robert Morell
2010-12-17 22:35 ` Greg KH
2010-12-17 22:42 ` rmorell
2010-12-17 23:09 ` Greg KH
2010-12-17 23:17 ` Oliver Neukum
2010-12-17 23:35 ` Greg KH
2010-12-17 23:50 ` rmorell
2010-12-17 23:40 ` rmorell
2010-12-18 0:37 ` Greg KH
2010-12-18 1:29 ` rmorell
2010-12-17 22:32 ` [RFC] Align tegra-ehci DMA transfers to 32B Greg KH
2010-12-17 22:44 ` rmorell
2010-12-17 23:07 ` Greg KH
2010-12-17 23:07 ` David Brownell
2010-12-18 1:49 ` [PATCH v2] " Robert Morell
2010-12-19 21:38 ` [PATCH] " Robert Morell
2011-01-06 23:20 ` [PATCH v4] " Robert Morell
2011-01-20 21:41 ` [PATCH v5] " Robert Morell
2011-01-27 3:06 ` [PATCH v6] " Robert Morell
2011-01-27 3:06 ` [PATCH 1/3] USB: HCD: Add usb_hcd prefix to exported functions Robert Morell
2011-01-27 16:01 ` Alan Stern
2011-01-27 3:06 ` [PATCH 2/3] USB: HCD: Add driver hooks for (un)?map_urb_for_dma Robert Morell
2011-01-27 16:01 ` Alan Stern
2011-01-27 3:06 ` [PATCH 3/3] USB: ehci: tegra: Align DMA transfers to 32 bytes Robert Morell
2011-02-04 19:49 ` Greg KH
2011-02-04 20:14 ` Olof Johansson
2011-02-04 20:16 ` Greg KH
2011-02-04 20:26 ` rmorell
2011-02-04 20:35 ` Greg KH
2011-01-20 21:41 ` [PATCH 1/2] USB: HCD: Add driver hooks for (un)?map_urb_for_dma Robert Morell
2011-01-23 3:46 ` Greg KH
2011-01-24 16:32 ` Alan Stern
2011-01-20 21:41 ` [PATCH 2/2] USB: ehci: tegra: Align DMA transfers to 32 bytes Robert Morell
2011-01-24 16:36 ` Alan Stern
2011-01-24 22:53 ` rmorell
2011-01-25 2:59 ` Alan Stern
2011-01-06 23:20 ` [PATCH v4 1/2] USB: HCD: Add driver hooks for (un)?map_urb_for_dma Robert Morell
2011-01-06 23:20 ` [PATCH v4 2/2] USB: ehci: tegra: Align DMA transfers to 32 bytes Robert Morell
2010-12-19 21:38 ` [PATCH 1/2] USB: Add driver hooks for (un)?map_urb_for_dma Robert Morell
2010-12-19 21:38 ` Robert Morell [this message]
2010-12-19 21:57 ` [PATCH 2/2] USB: ehci: tegra: Align DMA transfers to 32 bytes Oliver Neukum
2010-12-18 1:49 ` [PATCH v2 1/2] USB: Add driver hooks for (un)?map_urb_for_dma Robert Morell
2010-12-18 17:51 ` Greg KH
2010-12-18 1:49 ` [PATCH v2 2/2] USB: ehci: tegra: Align DMA transfers to 32 bytes Robert Morell
2010-12-18 17:52 ` Greg KH
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