Re: [PATCH 2/2] usb: host: ehci-msm: Use posted data writes on AHB

From: Alan Stern
Date: Fri Nov 06 2015 - 10:41:14 EST


On Fri, 6 Nov 2015, Georgi Djakov wrote:

> On 11/06/2015 08:04 AM, Andy Gross wrote:
> > This patch sets the AHBMODE to allow for posted data writes. This
> > results in higher performance.
> >
> > Signed-off-by: Andy Gross <agross@xxxxxxxxxxxxxx>
>
> With these patches I see significant improvement in throughput
> on my db410c board.
>
> Tested-by: Georgi Djakov <georgi.djakov@xxxxxxxxxx>
>
> > ---
> > drivers/usb/host/ehci-msm.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/usb/host/ehci-msm.c b/drivers/usb/host/ehci-msm.c
> > index c4f84c8..c23e285 100644
> > --- a/drivers/usb/host/ehci-msm.c
> > +++ b/drivers/usb/host/ehci-msm.c
> > @@ -57,8 +57,8 @@ static int ehci_msm_reset(struct usb_hcd *hcd)
> >
> > /* bursts of unspecified length. */
> > writel(0, USB_AHBBURST);
> > - /* Use the AHB transactor */
> > - writel(0, USB_AHBMODE);
> > + /* Use the AHB transactor, allow posted data writes */
> > + writel(0x8, USB_AHBMODE);
> > /* Disable streaming mode and select host mode */
> > writel(0x13, USB_USBMODE);

Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>

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