Commit 38c5df22 authored by Felipe Balbi's avatar Felipe Balbi
Browse files

usb: musb: gadget: delete wrong comment 



Those comments haven't been updated for a long
time, so much that they don't make sense anymore.

Best to remove them.

Signed-off-by: default avatarFelipe Balbi <balbi@ti.com>
parent b42f7f30

drivers/usb/musb/musb_gadget.c

+0 −108
Original line number Diff line number Diff line
@@ -46,48 +46,6 @@ 
#include "musb_core.h"





/* MUSB PERIPHERAL status 3-mar-2006:

 *

 * - EP0 seems solid.  It passes both USBCV and usbtest control cases.

 *   Minor glitches:

 *

 *     + remote wakeup to Linux hosts work, but saw USBCV failures;

 *       in one test run (operator error?)

 *     + endpoint halt tests -- in both usbtest and usbcv -- seem

 *       to break when dma is enabled ... is something wrongly

 *       clearing SENDSTALL?

 *

 * - Mass storage behaved ok when last tested.  Network traffic patterns

 *   (with lots of short transfers etc) need retesting; they turn up the

 *   worst cases of the DMA, since short packets are typical but are not

 *   required.

 *

 * - TX/IN

 *     + both pio and dma behave in with network and g_zero tests

 *     + no cppi throughput issues other than no-hw-queueing

 *     + failed with FLAT_REG (DaVinci)

 *     + seems to behave with double buffering, PIO -and- CPPI

 *     + with gadgetfs + AIO, requests got lost?

 *

 * - RX/OUT

 *     + both pio and dma behave in with network and g_zero tests

 *     + dma is slow in typical case (short_not_ok is clear)

 *     + double buffering ok with PIO

 *     + double buffering *FAILS* with CPPI, wrong data bytes sometimes

 *     + request lossage observed with gadgetfs

 *

 * - ISO not tested ... might work, but only weakly isochronous

 *

 * - Gadget driver disabling of softconnect during bind() is ignored; so

 *   drivers can't hold off host requests until userspace is ready.

 *   (Workaround:  they can turn it off later.)

 *

 * - PORTABILITY (assumes PIO works):

 *     + DaVinci, basically works with cppi dma

 *     + OMAP 2430, ditto with mentor dma

 *     + TUSB 6010, platform-specific dma in the works

 */



/* ----------------------------------------------------------------------- */



#define is_buffer_mapped(req) (is_dma_capable() && \
@@ -275,41 +233,6 @@ static inline int max_ep_writesize(struct musb *musb, struct musb_ep *ep) 
		return ep->packet_sz;

}





#ifdef CONFIG_USB_INVENTRA_DMA



/* Peripheral tx (IN) using Mentor DMA works as follows:

	Only mode 0 is used for transfers <= wPktSize,

	mode 1 is used for larger transfers,



	One of the following happens:

	- Host sends IN token which causes an endpoint interrupt

		-> TxAvail

			-> if DMA is currently busy, exit.

			-> if queue is non-empty, txstate().



	- Request is queued by the gadget driver.

		-> if queue was previously empty, txstate()



	txstate()

		-> start

		  /\	-> setup DMA

		  |     (data is transferred to the FIFO, then sent out when

		  |	IN token(s) are recd from Host.

		  |		-> DMA interrupt on completion

		  |		   calls TxAvail.

		  |		      -> stop DMA, ~DMAENAB,

		  |		      -> set TxPktRdy for last short pkt or zlp

		  |		      -> Complete Request

		  |		      -> Continue next request (call txstate)

		  |___________________________________|



 * Non-Mentor DMA engines can of course work differently, such as by

 * upleveling from irq-per-packet to irq-per-buffer.

 */



#endif



/*

 * An endpoint is transmitting data. This can be called either from

 * the IRQ routine or from ep.queue() to kickstart a request on an
@@ -616,37 +539,6 @@ void musb_g_tx(struct musb *musb, u8 epnum) 


/* ------------------------------------------------------------ */



#ifdef CONFIG_USB_INVENTRA_DMA



/* Peripheral rx (OUT) using Mentor DMA works as follows:

	- Only mode 0 is used.



	- Request is queued by the gadget class driver.

		-> if queue was previously empty, rxstate()



	- Host sends OUT token which causes an endpoint interrupt

	  /\      -> RxReady

	  |	      -> if request queued, call rxstate

	  |		/\	-> setup DMA

	  |		|	     -> DMA interrupt on completion

	  |		|		-> RxReady

	  |		|		      -> stop DMA

	  |		|		      -> ack the read

	  |		|		      -> if data recd = max expected

	  |		|				by the request, or host

	  |		|				sent a short packet,

	  |		|				complete the request,

	  |		|				and start the next one.

	  |		|_____________________________________|

	  |					 else just wait for the host

	  |					    to send the next OUT token.

	  |__________________________________________________|



 * Non-Mentor DMA engines can of course work differently.

 */



#endif



/*

 * Context: controller locked, IRQs blocked, endpoint selected

 */