musb: am335x: disable bulk split-combine feature

On TI AM335x devices, MUSB has bulk split/combine feature enabled
in the ConfigData register, but the current MUSB driver does not
support it yet. Therefore, disable the feature for now, until the
driver adds the support.

One usecase which is broken because of this feature is that Ether
gadget stops working in Fullspeed mode (by un-defining
CONFIG_USB_GADGET_DUALSPEED)

After desabled this feature, MUSB driver send packets in proper size
(no more than 64 bytes) in Fullspeed mode.

This has been validated with Ether gadget in Fullspeed mode on AM335x
EVM.

Signed-off-by: Bin Liu <b-liu@ti.com>

drivers/usb/musb-new/musb_core.c

@@ -1421,6 +1421,7 @@ static int __devinit musb_core_init(u16 musb_type, struct musb *musb)
 		strcat(aInfo, ", dyn FIFOs");
 		musb->dyn_fifo = true;
 	}
+#ifndef CONFIG_MUSB_DISABLE_BULK_COMBINE_SPLIT
 	if (reg & MUSB_CONFIGDATA_MPRXE) {
 		strcat(aInfo, ", bulk combine");
 		musb->bulk_combine = true;
@@ -1429,6 +1430,10 @@ static int __devinit musb_core_init(u16 musb_type, struct musb *musb)
 		strcat(aInfo, ", bulk split");
 		musb->bulk_split = true;
 	}
+#else
+	musb->bulk_combine = false;
+	musb->bulk_split = false;
+#endif
 	if (reg & MUSB_CONFIGDATA_HBRXE) {
 		strcat(aInfo, ", HB-ISO Rx");
 		musb->hb_iso_rx = true;

include/configs/am335x_evm.h

@@ -352,6 +352,7 @@
 #define CONFIG_ARCH_MISC_INIT
 #define CONFIG_MUSB_GADGET
 #define CONFIG_MUSB_PIO_ONLY
+#define CONFIG_MUSB_DISABLE_BULK_COMBINE_SPLIT
 #define CONFIG_USB_GADGET_DUALSPEED
 #define CONFIG_MUSB_HOST
 #define CONFIG_AM335X_USB0