Re: [PATCH v2 09/12] usb: chipidea: udc: add the define TD_PAGE_COUNT and fix all users

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Hi,

On Tue, Mar 26, 2013 at 05:58:45PM +0100, Michael Grzeschik wrote:
> A static count of transfer descriptors was used everywhere in the driver
> with the fixed number 5. This patch adds a define, named TD_PAGE_COUNT,
> and replaces all users of this value. This way its possible to have only
> one parameter to change and limit the amount of buffer pointers per TD.
> 
> Signed-off-by: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx>
> ---
> Changes since v1:
>  - renamed TD_COUNT to more precise TD_PAGE_COUNT
>  - changed TD_PAGE_COUNT to 5 based on the previous patch
>  - fixed patch description to address the tds buffers not the td itself
> 
>  drivers/usb/chipidea/ci.h  | 1 +
>  drivers/usb/chipidea/udc.c | 6 +++---
>  2 files changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/chipidea/ci.h b/drivers/usb/chipidea/ci.h
> index 7dcd390..4ca3373 100644
> --- a/drivers/usb/chipidea/ci.h
> +++ b/drivers/usb/chipidea/ci.h
> @@ -21,6 +21,7 @@
>  /******************************************************************************
>   * DEFINE
>   *****************************************************************************/
> +#define TD_PAGE_COUNT      5
>  #define CI13XXX_PAGE_SIZE  4096ul /* page size for TD's */
>  #define ENDPT_MAX          32
>  #define RX        0  /* similar to USB_DIR_OUT but can be used as an index */
> diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
> index e779870..4294c2c 100644
> --- a/drivers/usb/chipidea/udc.c
> +++ b/drivers/usb/chipidea/udc.c
> @@ -445,7 +445,7 @@ _hardware_enqueue(struct ci13xxx_ep *mEp, struct ci13xxx_req *mReq,
>  			mReq->ptr->token  |= TD_IOC;
>  	}
>  	mReq->ptr->page[0]  = mReq->req.dma;
> -	for (i = 1; i < 5; i++)
> +	for (i = 1; i < TD_PAGE_COUNT; i++)
>  		mReq->ptr->page[i] =
>  			(mReq->req.dma + i * CI13XXX_PAGE_SIZE) & ~TD_RESERVED_MASK;
>  
> @@ -697,8 +697,8 @@ static int _ep_queue(struct usb_ep *ep, struct usb_request *req,
>  		goto done;
>  	}
>  
> -	if (req->length > 4 * CI13XXX_PAGE_SIZE) {
> -		req->length = 4 * CI13XXX_PAGE_SIZE;
> +	if (req->length > (TD_PAGE_COUNT - 1) * CI13XXX_PAGE_SIZE) {
> +		req->length = (TD_PAGE_COUNT - 1) * CI13XXX_PAGE_SIZE;

this is a bug. You shouldn't change req->length, you might completely
screw up a gadget driver. Don't change anything what the gadget driver
passes to you, ever. Change some private structure instead.

(yeah, I know it's not part of $subject)

Reviewed-by: Felipe Balbi <balbi@xxxxxx>


-- 
balbi

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