On Tuesday 21 April 2009, Robert Jarzmik wrote:
> Got pxa27x_udc working on the pxa320 Nomad platform. The
> problem was that the pxa3xx UDC is not quite compatible with
> the pxa27x UDC in how it handles back-to-back control
> packets. The pxa27x probably drops them by default, but the
> pxa320 does not, and you have to detect it and set the OPC
> bit to clear the zero-length packet.
>
> Signed-off-by: Aric Blumer <aric@xxxxxxxxxxxxxx>
> Signed-off-by: Robert Jarzmik <robert.jarzmik@xxxxxxx>
Acked-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
> ---
> drivers/usb/gadget/Kconfig | 2 +-
> drivers/usb/gadget/pxa27x_udc.c | 13 ++++++++++++-
> 2 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
> index 080bb1e..772dd3b 100644
> --- a/drivers/usb/gadget/Kconfig
> +++ b/drivers/usb/gadget/Kconfig
> @@ -253,7 +253,7 @@ config USB_PXA25X_SMALL
>
> config USB_GADGET_PXA27X
> boolean "PXA 27x"
> - depends on ARCH_PXA && PXA27x
> + depends on ARCH_PXA && (PXA27x || PXA3xx)
> select USB_OTG_UTILS
> help
> Intel's PXA 27x series XScale ARM v5TE processors include
> diff --git a/drivers/usb/gadget/pxa27x_udc.c b/drivers/usb/gadget/pxa27x_udc.c
> index ffe6e0a..51790b0 100644
> --- a/drivers/usb/gadget/pxa27x_udc.c
> +++ b/drivers/usb/gadget/pxa27x_udc.c
> @@ -1892,6 +1892,15 @@ static void handle_ep0_ctrl_req(struct pxa_udc *udc,
>
> nuke(ep, -EPROTO);
>
> + /*
> + * In the PXA320 manual, in the section about Back-to-Back setup
> + * packets, it describes this situation. The solution is to set OPC to
> + * get rid of the status packet, and then continue with the setup
> + * packet. Generalize to pxa27x CPUs.
> + */
> + if (epout_has_pkt(ep) && (ep_count_bytes_remain(ep) == 0))
> + udc_ep_writel(ep, UDCCSR, UDCCSR0_OPC);
> +
> /* read SETUP packet */
> for (i = 0; i < 2; i++) {
> if (unlikely(ep_is_empty(ep)))
> @@ -1965,6 +1974,8 @@ stall:
> * cleared by software.
> * - clearing UDCCSR0_OPC always flushes ep0. If in setup stage, never do it
> * before reading ep0.
> + * This is true only for PXA27x. This is not true anymore for PXA3xx family
> + * (check Back-to-Back setup packet in developers guide).
> * - irq can be called on a "packet complete" event (opc_irq=1), while
> * UDCCSR0_OPC is not yet raised (delta can be as big as 100ms
> * from experimentation).
> @@ -2575,7 +2586,7 @@ static struct platform_driver udc_driver = {
>
> static int __init udc_init(void)
> {
> - if (!cpu_is_pxa27x())
> + if (!cpu_is_pxa27x() && !cpu_is_pxa3xx())
> return -ENODEV;
>
> printk(KERN_INFO "%s: version %s\n", driver_name, DRIVER_VERSION);
> --
> 1.6.2.1
>
>
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