Re: [PATCH v2] USB: xHCI: Sync non-coherent DMA buffers

From: Lucas Stach <l.stach@pengutronix.de>
To: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH v2] USB: xHCI: Sync non-coherent DMA buffers
Date: Wed, 15 Apr 2015 11:10:07 +0200	[thread overview]
Message-ID: <1429089007.3365.9.camel@pengutronix.de> (raw)
In-Reply-To: <1428934950-6836-1-git-send-email-sebastian.hesselbarth@gmail.com>

Am Montag, den 13.04.2015, 16:22 +0200 schrieb Sebastian Hesselbarth:
> When working with non-coherent transfer buffers, we have to sync
> device and cpu for outgoing and incoming buffers. Fix the driver where
> non-coherent buffers are used in device context.
> 
> Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>

Reviewed-by: Lucas Stach <l.stach@pengutronix.de>

> ---
> Changelog:
> v1->v2:
> - balance dma_sync_single_foo() calls (Reported by Lucas Stach)
> 
> Cc: barebox@lists.infradead.org
> Cc: Lucas Stach <dev@lynxeye.de>
> ---
>  drivers/usb/host/xhci-hcd.c | 23 ++++++++++++++++++++++-
>  1 file changed, 22 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/host/xhci-hcd.c b/drivers/usb/host/xhci-hcd.c
> index c3d623e91f51..a44a1a4dffa5 100644
> --- a/drivers/usb/host/xhci-hcd.c
> +++ b/drivers/usb/host/xhci-hcd.c
> @@ -1024,6 +1024,11 @@ static int xhci_submit_normal(struct usb_device *udev, unsigned long pipe,
>  		GET_SLOT_STATE(le32_to_cpu(vdev->out_ctx->slot.dev_state)), epi,
>  		vdev->in_ctx, vdev->out_ctx);
>  
> +	/* pass ownership of data buffer to device */
> +	dma_sync_single_for_device((unsigned long)buffer, length,
> +				   usb_pipein(pipe) ?
> +				   DMA_FROM_DEVICE : DMA_TO_DEVICE);
> +
>  	/* Normal TRB */
>  	memset(&trb, 0, sizeof(union xhci_trb));
>  	trb.event_cmd.cmd_trb = cpu_to_le64((dma_addr_t)buffer);
> @@ -1037,6 +1042,11 @@ static int xhci_submit_normal(struct usb_device *udev, unsigned long pipe,
>  	ret = xhci_wait_for_event(xhci, TRB_TRANSFER, &trb);
>  	xhci_print_trb(xhci, &trb, "Response Normal");
>  
> +	/* Regain ownership of data buffer from device */
> +	dma_sync_single_for_cpu((unsigned long)buffer, length,
> +				usb_pipein(pipe) ?
> +				DMA_FROM_DEVICE : DMA_TO_DEVICE);
> +
>  	switch (ret) {
>  	case -COMP_SHORT_TX:
>  		udev->status = 0;
> @@ -1094,6 +1104,11 @@ static int xhci_submit_control(struct usb_device *udev, unsigned long pipe,
>  			return ret;
>  	}
>  
> +	/* Pass ownership of data buffer to device */
> +	dma_sync_single_for_device((unsigned long)buffer, length,
> +				   (req->requesttype & USB_DIR_IN) ?
> +				   DMA_FROM_DEVICE : DMA_TO_DEVICE);
> +
>  	/* Setup TRB */
>  	memset(&trb, 0, sizeof(union xhci_trb));
>  	trb.generic.field[0] = le16_to_cpu(req->value) << 16 |
> @@ -1141,11 +1156,17 @@ static int xhci_submit_control(struct usb_device *udev, unsigned long pipe,
>  		if (ret == -COMP_SHORT_TX)
>  			length -= EVENT_TRB_LEN(trb.event_cmd.status);
>  		else if (ret < 0)
> -			return ret;
> +			goto dma_regain;
>  	}
>  
>  	ret = xhci_wait_for_event(xhci, TRB_TRANSFER, &trb);
>  	xhci_print_trb(xhci, &trb, "Response Status");
> +
> +dma_regain:
> +	/* Regain ownership of data buffer from device */
> +	dma_sync_single_for_cpu((unsigned long)buffer, length,
> +				(req->requesttype & USB_DIR_IN) ?
> +				DMA_FROM_DEVICE : DMA_TO_DEVICE);
>  	if (ret < 0)
>  		return ret;
>  

-- 
Pengutronix e.K.             | Lucas Stach                 |
Industrial Linux Solutions   | http://www.pengutronix.de/  |


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