Commit 2ae61a25 authored by Michał Mirosław's avatar Michał Mirosław Committed by Greg Kroah-Hartman
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usb: chipidea: Simplify Tegra DMA alignment code 



The USB host on Tegra3 works with 32-bit alignment. Previous code tried
to align the buffer, but it did align the wrapper struct instead, so
the buffer was at a constant offset of 8 bytes (two pointers) from
expected alignment.  Since kmalloc() guarantees at least 8-byte
alignment already, the alignment-extending is removed.

Fixes: fc53d527 ("usb: chipidea: tegra: Support host mode")
Signed-off-by: default avatarMichał Mirosław <mirq-linux@rere.qmqm.pl>
Link: https://lore.kernel.org/r/a0d917d492b1f91ee0019e68b8e8bca9c585393f.1695934946.git.mirq-linux@rere.qmqm.pl


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7ab87167

drivers/usb/chipidea/host.c

+18 −27
Original line number Diff line number Diff line
@@ -30,8 +30,7 @@ struct ehci_ci_priv { 
};



struct ci_hdrc_dma_aligned_buffer {

	void *kmalloc_ptr;

	void *old_xfer_buffer;

	void *original_buffer;

	u8 data[];

};
@@ -380,60 +379,52 @@ static int ci_ehci_bus_suspend(struct usb_hcd *hcd) 
	return 0;

}



static void ci_hdrc_free_dma_aligned_buffer(struct urb *urb)

static void ci_hdrc_free_dma_aligned_buffer(struct urb *urb, bool copy_back)

{

	struct ci_hdrc_dma_aligned_buffer *temp;

	size_t length;



	if (!(urb->transfer_flags & URB_ALIGNED_TEMP_BUFFER))

		return;

	urb->transfer_flags &= ~URB_ALIGNED_TEMP_BUFFER;



	temp = container_of(urb->transfer_buffer,

			    struct ci_hdrc_dma_aligned_buffer, data);

	urb->transfer_buffer = temp->original_buffer;



	if (copy_back && usb_urb_dir_in(urb)) {

		size_t length;



	if (usb_urb_dir_in(urb)) {

		if (usb_pipeisoc(urb->pipe))

			length = urb->transfer_buffer_length;

		else

			length = urb->actual_length;



		memcpy(temp->old_xfer_buffer, temp->data, length);

		memcpy(temp->original_buffer, temp->data, length);

	}

	urb->transfer_buffer = temp->old_xfer_buffer;

	kfree(temp->kmalloc_ptr);



	urb->transfer_flags &= ~URB_ALIGNED_TEMP_BUFFER;

	kfree(temp);

}



static int ci_hdrc_alloc_dma_aligned_buffer(struct urb *urb, gfp_t mem_flags)

{

	struct ci_hdrc_dma_aligned_buffer *temp, *kmalloc_ptr;

	const unsigned int ci_hdrc_usb_dma_align = 32;

	size_t kmalloc_size;

	struct ci_hdrc_dma_aligned_buffer *temp;



	if (urb->num_sgs || urb->sg || urb->transfer_buffer_length == 0)

		return 0;

	if (!((uintptr_t)urb->transfer_buffer & (ci_hdrc_usb_dma_align - 1)) && !(urb->transfer_buffer_length & 3))

	if (IS_ALIGNED((uintptr_t)urb->transfer_buffer, 4)

	    && IS_ALIGNED(urb->transfer_buffer_length, 4))

		return 0;



	/* Allocate a buffer with enough padding for alignment */

	kmalloc_size = ALIGN(urb->transfer_buffer_length, 4) +

		       sizeof(struct ci_hdrc_dma_aligned_buffer) +

		       ci_hdrc_usb_dma_align - 1;



	kmalloc_ptr = kmalloc(kmalloc_size, mem_flags);

	if (!kmalloc_ptr)

	temp = kmalloc(sizeof(*temp) + ALIGN(urb->transfer_buffer_length, 4), mem_flags);

	if (!temp)

		return -ENOMEM;



	/* Position our struct dma_aligned_buffer such that data is aligned */

	temp = PTR_ALIGN(kmalloc_ptr + 1, ci_hdrc_usb_dma_align) - 1;

	temp->kmalloc_ptr = kmalloc_ptr;

	temp->old_xfer_buffer = urb->transfer_buffer;

	if (usb_urb_dir_out(urb))

		memcpy(temp->data, urb->transfer_buffer,

		       urb->transfer_buffer_length);

	urb->transfer_buffer = temp->data;



	temp->original_buffer = urb->transfer_buffer;

	urb->transfer_buffer = temp->data;

	urb->transfer_flags |= URB_ALIGNED_TEMP_BUFFER;



	return 0;
@@ -450,7 +441,7 @@ static int ci_hdrc_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb, 


	ret = usb_hcd_map_urb_for_dma(hcd, urb, mem_flags);

	if (ret)

		ci_hdrc_free_dma_aligned_buffer(urb);

		ci_hdrc_free_dma_aligned_buffer(urb, false);



	return ret;

}
@@ -458,7 +449,7 @@ static int ci_hdrc_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb, 
static void ci_hdrc_unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)

{

	usb_hcd_unmap_urb_for_dma(hcd, urb);

	ci_hdrc_free_dma_aligned_buffer(urb);

	ci_hdrc_free_dma_aligned_buffer(urb, true);

}



#ifdef CONFIG_PM_SLEEP