+++ /dev/null
-From 028c9191bdf88f120f65626920a6a679170fcc3e Mon Sep 17 00:00:00 2001
-From: =?UTF-8?q?Antti=20Sepp=C3=A4l=C3=A4?= <a.seppala@gmail.com>
-Date: Thu, 5 Jul 2018 11:37:03 +0300
-Subject: [PATCH 1/2] usb: dwc2: Fix DMA alignment to start at allocated
- boundary
-MIME-Version: 1.0
-Content-Type: text/plain; charset=UTF-8
-Content-Transfer-Encoding: 8bit
-
-The commit 3bc04e28a030 ("usb: dwc2: host: Get aligned DMA in a more
-supported way") introduced a common way to align DMA allocations.
-The code in the commit aligns the struct dma_aligned_buffer but the
-actual DMA address pointed by data[0] gets aligned to an offset from
-the allocated boundary by the kmalloc_ptr and the old_xfer_buffer
-pointers.
-
-This is against the recommendation in Documentation/DMA-API.txt which
-states:
-
- Therefore, it is recommended that driver writers who don't take
- special care to determine the cache line size at run time only map
- virtual regions that begin and end on page boundaries (which are
- guaranteed also to be cache line boundaries).
-
-The effect of this is that architectures with non-coherent DMA caches
-may run into memory corruption or kernel crashes with Unhandled
-kernel unaligned accesses exceptions.
-
-Fix the alignment by positioning the DMA area in front of the allocation
-and use memory at the end of the area for storing the orginal
-transfer_buffer pointer. This may have the added benefit of increased
-performance as the DMA area is now fully aligned on all architectures.
-
-Tested with Lantiq xRX200 (MIPS) and RPi Model B Rev 2 (ARM).
-
-Fixes: 3bc04e28a030 ("usb: dwc2: host: Get aligned DMA in a more
-supported way")
-
-Signed-off-by: Antti Seppälä <a.seppala@gmail.com>
----
- drivers/usb/dwc2/hcd.c | 44 +++++++++++++++++++++++---------------------
- 1 file changed, 23 insertions(+), 21 deletions(-)
-
---- a/drivers/usb/dwc2/hcd.c
-+++ b/drivers/usb/dwc2/hcd.c
-@@ -2628,34 +2628,29 @@ static void dwc2_hc_init_xfer(struct dwc
-
- #define DWC2_USB_DMA_ALIGN 4
-
--struct dma_aligned_buffer {
-- void *kmalloc_ptr;
-- void *old_xfer_buffer;
-- u8 data[0];
--};
--
- static void dwc2_free_dma_aligned_buffer(struct urb *urb)
- {
-- struct dma_aligned_buffer *temp;
-+ void *stored_xfer_buffer;
-
- if (!(urb->transfer_flags & URB_ALIGNED_TEMP_BUFFER))
- return;
-
-- temp = container_of(urb->transfer_buffer,
-- struct dma_aligned_buffer, data);
-+ /* Restore urb->transfer_buffer from the end of the allocated area */
-+ memcpy(&stored_xfer_buffer, urb->transfer_buffer +
-+ urb->transfer_buffer_length, sizeof(urb->transfer_buffer));
-
- if (usb_urb_dir_in(urb))
-- memcpy(temp->old_xfer_buffer, temp->data,
-+ memcpy(stored_xfer_buffer, urb->transfer_buffer,
- urb->transfer_buffer_length);
-- urb->transfer_buffer = temp->old_xfer_buffer;
-- kfree(temp->kmalloc_ptr);
-+ kfree(urb->transfer_buffer);
-+ urb->transfer_buffer = stored_xfer_buffer;
-
- urb->transfer_flags &= ~URB_ALIGNED_TEMP_BUFFER;
- }
-
- static int dwc2_alloc_dma_aligned_buffer(struct urb *urb, gfp_t mem_flags)
- {
-- struct dma_aligned_buffer *temp, *kmalloc_ptr;
-+ void *kmalloc_ptr;
- size_t kmalloc_size;
-
- if (urb->num_sgs || urb->sg ||
-@@ -2663,22 +2658,29 @@ static int dwc2_alloc_dma_aligned_buffer
- !((uintptr_t)urb->transfer_buffer & (DWC2_USB_DMA_ALIGN - 1)))
- return 0;
-
-- /* Allocate a buffer with enough padding for alignment */
-+ /*
-+ * Allocate a buffer with enough padding for original transfer_buffer
-+ * pointer. This allocation is guaranteed to be aligned properly for
-+ * DMA
-+ */
- kmalloc_size = urb->transfer_buffer_length +
-- sizeof(struct dma_aligned_buffer) + DWC2_USB_DMA_ALIGN - 1;
-+ sizeof(urb->transfer_buffer);
-
- kmalloc_ptr = kmalloc(kmalloc_size, mem_flags);
- if (!kmalloc_ptr)
- return -ENOMEM;
-
-- /* Position our struct dma_aligned_buffer such that data is aligned */
-- temp = PTR_ALIGN(kmalloc_ptr + 1, DWC2_USB_DMA_ALIGN) - 1;
-- temp->kmalloc_ptr = kmalloc_ptr;
-- temp->old_xfer_buffer = urb->transfer_buffer;
-+ /*
-+ * Position value of original urb->transfer_buffer pointer to the end
-+ * of allocation for later referencing
-+ */
-+ memcpy(kmalloc_ptr + urb->transfer_buffer_length,
-+ &urb->transfer_buffer, sizeof(urb->transfer_buffer));
-+
- if (usb_urb_dir_out(urb))
-- memcpy(temp->data, urb->transfer_buffer,
-+ memcpy(kmalloc_ptr, urb->transfer_buffer,
- urb->transfer_buffer_length);
-- urb->transfer_buffer = temp->data;
-+ urb->transfer_buffer = kmalloc_ptr;
-
- urb->transfer_flags |= URB_ALIGNED_TEMP_BUFFER;
-
+++ /dev/null
-From 81da1738eee68f1961e03bdeb2d60cf0eb4dd713 Mon Sep 17 00:00:00 2001
-From: =?UTF-8?q?Antti=20Sepp=C3=A4l=C3=A4?= <a.seppala@gmail.com>
-Date: Thu, 5 Jul 2018 12:06:18 +0300
-Subject: [PATCH 2/2] usb: dwc2: Fix inefficient copy of unaligned buffers
-MIME-Version: 1.0
-Content-Type: text/plain; charset=UTF-8
-Content-Transfer-Encoding: 8bit
-
-Make sure only to copy any actual data rather than the whole buffer,
-when releasing the temporary buffer used for unaligned non-isochronous
-transfers.
-
-Taken directly from commit 0efd937e27d5e ("USB: ehci-tegra: fix inefficient
-copy of unaligned buffers")
-
-Tested with Lantiq xRX200 (MIPS) and RPi Model B Rev 2 (ARM)
-
-Signed-off-by: Antti Seppälä <a.seppala@gmail.com>
----
- drivers/usb/dwc2/hcd.c | 12 +++++++++---
- 1 file changed, 9 insertions(+), 3 deletions(-)
-
---- a/drivers/usb/dwc2/hcd.c
-+++ b/drivers/usb/dwc2/hcd.c
-@@ -2631,6 +2631,7 @@ static void dwc2_hc_init_xfer(struct dwc
- static void dwc2_free_dma_aligned_buffer(struct urb *urb)
- {
- void *stored_xfer_buffer;
-+ size_t length;
-
- if (!(urb->transfer_flags & URB_ALIGNED_TEMP_BUFFER))
- return;
-@@ -2639,9 +2640,14 @@ static void dwc2_free_dma_aligned_buffer
- memcpy(&stored_xfer_buffer, urb->transfer_buffer +
- urb->transfer_buffer_length, sizeof(urb->transfer_buffer));
-
-- if (usb_urb_dir_in(urb))
-- memcpy(stored_xfer_buffer, urb->transfer_buffer,
-- urb->transfer_buffer_length);
-+ if (usb_urb_dir_in(urb)) {
-+ if (usb_pipeisoc(urb->pipe))
-+ length = urb->transfer_buffer_length;
-+ else
-+ length = urb->actual_length;
-+
-+ memcpy(stored_xfer_buffer, urb->transfer_buffer, length);
-+ }
- kfree(urb->transfer_buffer);
- urb->transfer_buffer = stored_xfer_buffer;
-