usb: fixes for v3.7-rc4

We're reverting MUSB Mode 1 DMA patch which caused many regressions. Meanwhile
 Roger is cooking a better version of that patch, which will hopefully be ready
 for v3.8 merge window.
 
 We also fix an undeclared error in ux5000_remove() and another build error
 when we try to build USB_MUSB_OMAP2PLUS as a module.
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Merge tag 'fixes-for-v3.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb into usb-linus

usb: fixes for v3.7-rc4

We're reverting MUSB Mode 1 DMA patch which caused many regressions. Meanwhile
Roger is cooking a better version of that patch, which will hopefully be ready
for v3.8 merge window.

We also fix an undeclared error in ux5000_remove() and another build error
when we try to build USB_MUSB_OMAP2PLUS as a module.

drivers/usb/musb/musb_gadget.c

@@ -707,11 +707,12 @@ static void rxstate(struct musb *musb, struct musb_request *req)
 		fifo_count = musb_readw(epio, MUSB_RXCOUNT);
 
 		/*
-		 *  use mode 1 only if we expect data of at least ep packet_sz
-		 *  and have not yet received a short packet
+		 * Enable Mode 1 on RX transfers only when short_not_ok flag
+		 * is set. Currently short_not_ok flag is set only from
+		 * file_storage and f_mass_storage drivers
 		 */
-		if ((request->length - request->actual >= musb_ep->packet_sz) &&
-			(fifo_count >= musb_ep->packet_sz))
+
+		if (request->short_not_ok && fifo_count == musb_ep->packet_sz)
 			use_mode_1 = 1;
 		else
 			use_mode_1 = 0;
@@ -727,6 +728,27 @@ static void rxstate(struct musb *musb, struct musb_request *req)
 				c = musb->dma_controller;
 				channel = musb_ep->dma;
 
+	/* We use DMA Req mode 0 in rx_csr, and DMA controller operates in
+	 * mode 0 only. So we do not get endpoint interrupts due to DMA
+	 * completion. We only get interrupts from DMA controller.
+	 *
+	 * We could operate in DMA mode 1 if we knew the size of the tranfer
+	 * in advance. For mass storage class, request->length = what the host
+	 * sends, so that'd work.  But for pretty much everything else,
+	 * request->length is routinely more than what the host sends. For
+	 * most these gadgets, end of is signified either by a short packet,
+	 * or filling the last byte of the buffer.  (Sending extra data in
+	 * that last pckate should trigger an overflow fault.)  But in mode 1,
+	 * we don't get DMA completion interrupt for short packets.
+	 *
+	 * Theoretically, we could enable DMAReq irq (MUSB_RXCSR_DMAMODE = 1),
+	 * to get endpoint interrupt on every DMA req, but that didn't seem
+	 * to work reliably.
+	 *
+	 * REVISIT an updated g_file_storage can set req->short_not_ok, which
+	 * then becomes usable as a runtime "use mode 1" hint...
+	 */
+
 				/* Experimental: Mode1 works with mass storage use cases */
 				if (use_mode_1) {
 					csr |= MUSB_RXCSR_AUTOCLEAR;

drivers/usb/musb/ux500.c

@@ -65,7 +65,7 @@ static int __devinit ux500_probe(struct platform_device *pdev)
 	struct platform_device		*musb;
 	struct ux500_glue		*glue;
 	struct clk			*clk;
-
+	int				musbid;
 	int				ret = -ENOMEM;
 
 	glue = kzalloc(sizeof(*glue), GFP_KERNEL);

drivers/usb/otg/Kconfig

@@ -58,7 +58,7 @@ config USB_ULPI_VIEWPORT
 
 config TWL4030_USB
 	tristate "TWL4030 USB Transceiver Driver"
-	depends on TWL4030_CORE && REGULATOR_TWL4030
+	depends on TWL4030_CORE && REGULATOR_TWL4030 && USB_MUSB_OMAP2PLUS
 	select USB_OTG_UTILS
 	help
 	  Enable this to support the USB OTG transceiver on TWL4030
@@ -68,7 +68,7 @@ config TWL4030_USB
 
 config TWL6030_USB
 	tristate "TWL6030 USB Transceiver Driver"
-	depends on TWL4030_CORE && OMAP_USB2
+	depends on TWL4030_CORE && OMAP_USB2 && USB_MUSB_OMAP2PLUS
 	select USB_OTG_UTILS
 	help
 	  Enable this to support the USB OTG transceiver on TWL6030