Re: [PATCH 1/5] USB: gadget: Use Zero Interrupt Threshold Control for ci13xxx_msm

[Sergei Shtylyov <sshtylyov@mvista.com>]

Hello.

On 28-04-2011 12:01, Pavankumar Kondeti wrote:

> From: Anji jonnala <anjir@codeaurora.org>

> ITC (Interrupt Threshold Control) field is to set the maximum rate at which
> the device controller will issue interrupts.  The maximum interrupt interval
> is measured in micro frames.  Valid values are 0, 1, 2, 4, 8, 16, 32, 64.
> The default value is 8 micro frames.  Set ITC to zero for MSM to gain
> performance.

> Signed-off-by: Anji jonnala<anjir@codeaurora.org>
> Signed-off-by: Pavankumar Kondeti<pkondeti@codeaurora.org>
> ---
>   drivers/usb/gadget/ci13xxx_msm.c |    3 ++-
>   drivers/usb/gadget/ci13xxx_udc.c |   11 +++++++++++
>   drivers/usb/gadget/ci13xxx_udc.h |    3 +++
>   3 files changed, 16 insertions(+), 1 deletions(-)

> diff --git a/drivers/usb/gadget/ci13xxx_udc.c b/drivers/usb/gadget/ci13xxx_udc.c
> index e09178b..bd1a059 100644
> --- a/drivers/usb/gadget/ci13xxx_udc.c
> +++ b/drivers/usb/gadget/ci13xxx_udc.c
> @@ -318,6 +318,17 @@ static int hw_device_reset(struct ci13xxx *udc)
>   	hw_cwrite(CAP_USBMODE, USBMODE_CM, USBMODE_CM_DEVICE);
>   	hw_cwrite(CAP_USBMODE, USBMODE_SLOM, USBMODE_SLOM);  /* HW>= 2.3 */
>
> +	/*
> +	 * ITC (Interrupt Threshold Control) field is to set the maximum
> +	 * rate at which the device controller will issue interrupts.
> +	 * The maximum interrupt interval measured in micro frames.
> +	 * Valid values are 0, 1, 2, 4, 8, 16, 32, 64. The default value is
> +	 * 8 micro frames. If CPU can handle interrupts at faster rate, ITC
> +	 * can be set to lesser value to gain performance.
> +	 */
> +	if (udc->udc_driver->flags && CI13XXX_ZERO_ITC)

    I think you meant bitwise AND (&) here.

WBR, Sergei